JP7742734B2 - Terminal device and communication method - Google Patents

Description

The present invention relates to a terminal device and a communication method.

A radio access method and a radio network for cellular mobile communications (hereinafter also referred to as "Long Term Evolution (LTE)" or "EUTRA: Evolved Universal Terrestrial Radio Access") are being studied by the ^3rd Generation Partnership Project (3GPP). In LTE, a base station device is also referred to as an evolved NodeB (eNodeB), and a terminal device is also referred to as a User Equipment (UE). LTE is a cellular communication system in which multiple areas covered by a base station device are arranged in the form of cells. A single base station device may manage multiple serving cells.

3GPP has been working on formulating a wireless communication standard (NR: New Radio). 3GPP is also studying further expansion of the wireless communication standard (Non-Patent Document 1).

“Release 17 package for RAN”, RP-193216, RAN chairman, RAN1 chairman, RAN2 chairman, RAN3 chairman, 3GPP TSG RAN Meeting #86, Sitges, Spain, 9th ― 12th December, 2019

The present invention provides a terminal device that communicates efficiently and a communication method used in the terminal device.

(1) A first aspect of the present invention is a terminal device comprising a medium access control layer processing unit and a physical layer processing unit, wherein the medium access control layer processing unit determines whether a random access preamble group B is configured for a PRACH resource group used for a random access procedure that requests the application of repeated transmission for message 3 PUSCH, and the medium access control layer processing unit determines whether to request the application of repeated transmission for message 3 based on the determination and instructs the physical layer processing unit to transmit a PRACH.

(2) A second aspect of the present invention is a communication method used in a terminal device, comprising:
The method includes the steps of: determining whether a random access preamble group B is configured for a PRACH resource group used for a random access procedure that requests the application of repeated transmission for a PUSCH; determining whether to request the application of repeated transmission for a message 3 based on the determination; and instructing the transmission of a PRACH.

This invention allows terminal devices to communicate efficiently.

1 is a conceptual diagram of a wireless communication system 9 according to an aspect of the present embodiment. FIG. 1 is a diagram illustrating an example of the configuration of a resource grid according to an aspect of the present embodiment. FIG. 2 is a schematic block diagram illustrating an example of the configuration of a base station device 3 according to one aspect of the present embodiment. 1 is a schematic block diagram illustrating an example of the configuration of a terminal device 1 according to an aspect of the present embodiment. A figure showing an example of a random access procedure performed in a medium access control layer processing unit 15 in one aspect of this embodiment. A diagram showing an example of a random access resource selection process 5002 performed by the medium access control layer processing unit 15 according to one aspect of this embodiment. A figure showing an example of a random access resource selection process 5032X performed by the medium access control layer processing unit 15 according to one aspect of this embodiment. A figure showing an example of a random access procedure performed in a medium access control layer processing unit 15 in one aspect of this embodiment. A diagram showing the procedure for selecting "RA_TYPE" by the media access control layer processing unit 15 according to one aspect of this embodiment.

The following describes an embodiment of the present invention.

floor(C) may be a floor function for real number C. For example, floor(C) may be a function that outputs the largest integer that does not exceed real number C. ceil(D) may be a ceiling function for real number D. For example, ceil(D) may be a function that outputs the smallest integer that does not fall below real number D. mod(E,F) may be a function that outputs the remainder when E is divided by F. mod(E,F) may be a function that outputs a value corresponding to the remainder when E is divided by F. exp(G) = e^G, where e is Napier's constant. H^I represents H to the Ith power. max(J,K) is a function that outputs the maximum value of J and K. Here, max(J,K) is a function that outputs J or K when J and K are equal. min(L,M) is a function that outputs the maximum value of L and M. Here, when L and M are equal, min(L, M) is a function that outputs L or M. round(N) is a function that outputs the integer value closest to N. "・" indicates multiplication.

Figure 1 is a conceptual diagram of a wireless communication system 9 according to one aspect of this embodiment. In Figure 1, the wireless communication system includes terminal devices 1A-1C and a base station device 3 (BS#3: Base station#3). Hereinafter, terminal devices 1A-1C will be collectively referred to as terminal device 1 (UE#1: User Equipment#1), and the terminal device communicating with base station device 3 will also be referred to as terminal device 1 (UE#1: User Equipment#1).

In the wireless communication system 9, the terminal device 1 and the base station device 3 may use one or more communication methods. For example, CP-OFDM (Cyclic Prefix - Orthogonal Frequency Division Multiplexing) may be used in the downlink of the wireless communication system 9. Furthermore, either CP-OFDM or DFT-s-OFDM (Discrete Fourier Transform - Spread - Orthogonal Frequency Division Multiplexing) may be used in the uplink of the wireless communication system 9. Here, DFT-s-OFDM is a communication method in which transformed precoding is applied prior to signal generation in CP-OFDM. Here, transformed precoding is also referred to as DFT precoding.

As shown in FIG. 1, the base station device 3 may be configured with one transceiver device (or transmission point, transmission device, reception point, reception device, transmission/reception point). Alternatively, in some cases, the base station device 3 may be configured to include multiple transceivers. When the base station device 3 is configured with multiple transceivers, each of the multiple transceivers may be located in a different geographical location.

The base station device 3 may provide one or more serving cells. A serving cell may be defined as a set of resources used in the wireless communication system 9. Here, a serving cell is also referred to as a cell.

A serving cell may be configured to include one downlink component carrier and/or one uplink component carrier. A serving cell may be configured to include two or more downlink component carriers and/or two or more uplink component carriers. Downlink component carriers and uplink component carriers are also collectively referred to as component carriers.

For a component carrier, one or more SCS-specific carriers
One subcarrier-spacing configuration μ may be associated with one SCS-specific carrier.

Resources in the wireless communication system 9 may be managed using a resource grid that uses subcarrier indexes and OFDM symbol indexes.

The subcarrier spacing (SCS) Δf for a certain subcarrier spacing setting μ may be Δf= ^2μ ·15 kHz. For example, the subcarrier spacing setting μ may represent any of 0, 1, 2, 3, or 4.

A time unit _Tc = 1/( _Δfmax · _Nf ) may be used to express the length of the time domain. Here, _Δfmax = 480 kHz. _Nf = 4096. The constant κ may be κ = _Δfmax · _Nf /( _Δfref ·Nf _,ref ) = 64. _Δfref may be 15 kHz. _Nf,ref is 2048.

The transmission of downlink/uplink signals may be organized into radio frames (system frames, frames) of length _Tf , where _Tf = ( _Δfmax · _Nf /100)· _Ts = 10 ms.

A radio frame may include 10 subframes, where the length of a subframe T _sf = (Δf _max · N _f /1000) · T _s = 1 ms, and the number of OFDM symbols per subframe may be N ^subframe,μ _symb = N ^slot _symb · N ^subframe,μ _slot .

OFDM symbols are used as the time domain unit for the communication method used in wireless communication system 9. For example, OFDM symbols may be used as the time domain unit for CP-OFDM. Furthermore, OFDM symbols may be used as the time domain unit for DFT-s-OFDM.

A slot may be configured to include multiple OFDM symbols. For example, one slot may be configured by N ^slot _symb consecutive OFDM symbols. For example, in the normal CP setting, N ^slot _symb = 14. Also, in the extended CP setting, N ^slot _symb = 12.

The slots may be indexed in the time domain. For example, the slot index n ^μ _s may be given in ascending order as integer values ranging from 0 to N ^subframe,μ _slot −1 in a subframe. Also, the slot index n ^μ _s,f may be given in ascending order as integer values ranging from 0 to N ^frame,μ _slot −1 in a radio frame.

Figure 2 is a diagram showing an example of the configuration of a resource grid according to one aspect of this embodiment. In the resource grid of Figure 2, the horizontal axis represents the OFDM symbol index l _sym and the vertical axis represents the subcarrier index k _sc . The resource grid of Figure 2 includes N ^size,μ _grid,x ·N ^RB _sc subcarriers and N ^subframe,μ _symb OFDM symbols. Here, N ^size,μ _grid,x represents the bandwidth of the SCS-specific carrier. The value of N ^size,μ _grid,x is expressed in resource blocks.

Within the resource grid, a resource identified by a subcarrier index k _sc and an OFDM symbol index l _sym is called a resource element (RE).
It is also called the Element.

A resource block (RB) includes N ^RB _sc consecutive subcarriers. The resource block is a collective term for a common resource block, a physical resource block (PRB), and a virtual resource block (VRB). For example, N ^RB _sc may be 12.

A BWP (BandWidth Part) may be configured as a subset of the resource grid. Here, the BWP configured for the downlink is also referred to as the downlink BWP. The BWP configured for the uplink is also referred to as the uplink BWP.

An antenna port may be defined such that the channel over which a symbol on the antenna port is conveyed can be inferred from the channel over which another symbol on the same antenna port is conveyed. For example, a channel may correspond to a physical channel. Alternatively, a symbol may correspond to a modulation symbol assigned to a resource element. Here, "channel" may mean "propagation path." Alternatively, "channel" may mean "physical channel."

Two antenna ports are considered to be in a Quasi Co-Located (QCL) relationship if the large-scale properties of the channel through which symbols are transmitted at one antenna port can be estimated from the channel through which symbols are transmitted at the other antenna port. Here, the large-scale properties may include long-range channel properties. The large-scale properties may include some or all of delay spread, Doppler spread, Doppler shift, average gain, average delay, and spatial Rx parameters. A first antenna port and a second antenna port being QCL with respect to beam parameters may mean that the receive beam assumed by the receiver for the first antenna port and the receive beam assumed by the receiver for the second antenna port are the same (or correspond to each other). The first antenna port and the second antenna port being QCL with respect to beam parameters may mean that the transmit beam assumed by the receiving side for the first antenna port and the transmit beam assumed by the receiving side for the second antenna port are the same (or correspond to each other). The terminal device 1 may assume that the two antenna ports are QCL if the large-scale characteristics of the channel through which symbols are transmitted at one antenna port can be estimated from the channel through which symbols are transmitted at another antenna port. The two antenna ports being QCL may mean that the two antenna ports are assumed to be QCL.

Carrier aggregation may involve communication using multiple aggregated serving cells. Carrier aggregation may also involve communication using multiple aggregated component carriers. Carrier aggregation may also involve communication using multiple aggregated downlink component carriers. Carrier aggregation may also involve communication using multiple aggregated uplink component carriers.

Figure 3 is a schematic block diagram showing an example configuration of a base station device 3 according to one aspect of this embodiment. As shown in Figure 3, the base station device 3 includes a physical layer processing unit (radio transmission/reception unit) 30 and/or part or all of a higher layer processing unit 34. The physical layer processing unit 30 includes an antenna unit 31, an RF (Radio Frequency) processing unit 32, and part or all of a baseband processing unit 33. The higher layer processing unit 34 includes a medium access control layer (MAC layer) processing unit 35 and part or all of a radio resource control (RRC) layer processing unit 36.

The physical layer processing unit 30 performs physical layer processing. Here, physical layer processing may include some or all of the following: generating a baseband signal for a physical channel, generating a baseband signal for a physical signal, detecting information transmitted by the physical channel, and detecting information transmitted by the physical signal. Furthermore, physical layer processing may include mapping a transport channel to a physical channel. Here, a baseband signal is also referred to as a time-continuous signal.

For example, the physical layer processing unit 30 may generate a baseband signal for a downlink physical channel. Here, a transport block delivered from a higher layer on the DL-SCH may be placed on the downlink physical channel.

For example, the physical layer processing unit 30 may generate a baseband signal for the downlink physical signal.

For example, the physical layer processing unit 30 may attempt to detect information transmitted by the uplink physical channel. Here, the transport block of the information transmitted by the uplink physical channel may be delivered to higher layers on the UL-SCH.

For example, the physical layer processing unit 30 may attempt to detect information transmitted by an uplink physical signal.

The upper layer processing unit 34 performs some or all of the processing for the MAC (Medium Access Control) layer, Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer, and RRC layer. Here, the MAC layer is also referred to as the MAC sublayer. The PDCP layer is also referred to as the PDCP sublayer. The RLC layer is also referred to as the RLC sublayer. The RRC layer is also referred to as the RRC sublayer.

The medium access control layer processing unit (MAC layer processing unit) 35 performs MAC layer processing, which includes mapping between logical channels and transport channels, multiplexing one or more MAC SDUs (Service Data Units) into a transport block, and multiplexing one or more MAC SDUs of a transport block delivered from the physical layer on the UL-SCH.
This may include some or all of the following: disassembly into SDUs, application of Hybrid Automatic Repeat reQuest (HARQ) to transport blocks, and processing of scheduling requests.

The radio resource control layer processing unit 36 performs RRC layer processing. RRC layer processing may include some or all of broadcast signal management, RRC connection/RRC idle state management, and RRC reconfiguration.

The radio resource control layer processing unit 36 may manage RRC parameters used for various settings of the terminal device 1. For example, the radio resource control layer processing unit 36 may include the RRC parameters in an RRC message on a certain logical channel and transmit the RRC message to the terminal device 1. Here, the RRC message may be mapped to any of the BCCH (Broadcast Control CHannel), CCCH (Common Control CHannel), and DCCH (Dedicated Control CHannel).

The radio resource control layer processing unit 36 may determine the RRC parameters to be transmitted to the terminal device 1 based on the RRC parameters included in the RRC message transmitted from the terminal device 1. Here, the RRC message transmitted from the terminal device 1 may be related to a functional information report of the terminal device 1.

The physical layer processing unit 30 may perform some or all of the modulation processing, encoding processing, and transmission processing. The physical layer processing unit 30 may generate a physical signal based on some or all of the encoding processing, modulation processing, and baseband signal generation processing for the transport block. The physical layer processing unit 30 may place the physical signal in a certain BWP. The physical layer processing unit 30 may transmit the generated physical signal.

The physical layer processing unit 30 may perform either or both of demodulation and decoding. The physical layer processing unit 30 may deliver transport blocks of information detected based on the demodulation and decoding processes of the received physical signal to higher layers on the UL-SCH.

If carrier sensing is required in the band of the serving cell, the physical layer processing unit 30 may perform carrier sensing prior to transmitting the physical signal.

The RF unit 32 converts the signal received via the antenna unit 31 into a baseband signal.
The RF unit 32 outputs the baseband signal to the baseband unit 33.

The baseband unit 33 may digitize the baseband signal input from the RF unit 32. The baseband unit 33 may remove a portion corresponding to a cyclic prefix (CP) from the digitized baseband signal. The baseband unit 33 may perform a fast Fourier transform (FFT) on the baseband signal from which the CP has been removed to extract a frequency domain signal.

The baseband unit 33 may generate a baseband signal by performing an Inverse Fast Fourier Transform (IFFT) on the physical signal. The baseband unit 33 may add a CP to the generated baseband signal. The baseband unit 33 may convert the baseband signal to which the CP has been added into an analog signal. The baseband unit 33 may output the analog baseband signal to the RF unit 32.

The RF unit 32 may remove unnecessary frequency components from the baseband signal input from the baseband unit 33. The RF unit 32 may upconvert the baseband signal to a carrier frequency to generate an RF signal. The RF unit 32 may transmit the RF signal via the antenna unit 31. The RF unit 32 may also have a function for controlling transmission power.

One or more serving cells (or component carriers, downlink component carriers, uplink component carriers) may be configured for the terminal device 1.

Each of the serving cells configured for the terminal device 1 may be a PCell (Primary cell), a PSCell (Primary SCG cell), or an SCell (Secondary Cell).

The PCell is a serving cell included in the MCG (Master Cell Group). The PCell is the cell in which the terminal device 1 performs the initial connection establishment procedure or the connection re-establishment procedure (the cell in which the procedure was performed).

The PSCell is a serving cell included in an SCG (Secondary Cell Group). The PSCell is a serving cell in which the random access procedure is performed by the terminal device 1.

The SCell may be included in either the MCG or the SCG.

Serving cell group (cell group) is a general term for MCG, SCG, and PUCCH cell group. A serving cell group may include one or more serving cells (or component carriers). One or more serving cells (or component carriers) included in a serving cell group may be operated using carrier aggregation.

One or more downlink BWPs may be configured for the terminal device 1. One or more uplink BWPs may be configured for the terminal device 1.

Of one or more downlink BWPs configured for the terminal device 1, one downlink BWP may be set as the active downlink BWP (or one downlink BWP may be activated). Of one or more uplink BWPs configured for the terminal device 1, one uplink BWP may be set as the active uplink BWP (or one uplink BWP may be activated).

The physical layer processing unit 30 may attempt to transmit the PDSCH, PDCCH, and CSI-RS on the active downlink BWP. The physical layer processing unit 10 may attempt to receive the PDSCH, PDCCH, and CSI-RS on the active downlink BWP. The physical layer processing unit 30 may attempt to receive the PUCCH and PUSCH on the active uplink BWP. The physical layer processing unit 10 may attempt to transmit the PUCCH and PUSCH on the active uplink BWP. Here, the active downlink BWP and the active uplink BWP are collectively referred to as the active BWP.

The physical layer processing unit 30 may not attempt to transmit the PDSCH, PDCCH, or CSI-RS on an inactive downlink BWP (a downlink BWP that is not an active downlink BWP). The physical layer processing unit 10 may not attempt to receive the PDSCH, PDCCH, or CSI-RS on an inactive downlink BWP. The physical layer processing unit 30 may not attempt to receive the PUCCH or PUSCH on an inactive uplink BWP (an uplink BWP that is not an active uplink BWP). The physical layer processing unit 10 may not attempt to transmit the PUCCH or PUSCH on an inactive uplink BWP. Here, the inactive downlink BWP and the inactive uplink BWP are collectively referred to as the inactive BWP.

Downlink BWP switch is a procedure for deactivating one active downlink BWP of a serving cell and activating one of the inactive downlink BWPs of the serving cell. Downlink BWP switch may be controlled by the physical layer, MAC layer, or RRC layer.

Uplink BWP switching is used to deactivate one active uplink BWP of a serving cell and activate one of the inactive uplink BWPs of the serving cell. Uplink BWP switching may be controlled by the physical layer, MAC layer, or RRC layer.

Of the one or more downlink BWPs configured for the terminal device 1, two or more downlink BWPs may not be set as active downlink BWPs. For a given component carrier, one downlink BWP may be active at a given time.

Of the one or more uplink BWPs configured for the terminal device 1, two or more uplink BWPs may not be set as active uplink BWPs. For a given component carrier, one uplink BWP may be active at a given time.

For each downlink component carrier, one downlink BWP may be set as the active BWP. In other words, for a given downlink component carrier, two or more downlink BWPs may not be set as the active downlink BWP.

For each uplink component carrier, one uplink BWP may be set as the active BWP. In other words, for a given uplink component carrier, two or more uplink BWPs may not be set as the active uplink BWP.

Figure 4 is a schematic block diagram showing an example configuration of a terminal device 1 according to one aspect of this embodiment. As shown in Figure 4, the terminal device 1 includes a physical layer processing unit (radio transceiver unit) 10 and part or all of an upper layer processing unit 14. The radio transceiver unit 10 includes an antenna unit 11, an RF unit 12, and part or all of a baseband unit 13. The upper layer processing unit 14 includes a medium access control layer processing unit 15 and part or all of a radio resource control layer processing unit 16.

The physical layer processing unit 10 performs physical layer processing.

For example, the physical layer processing unit 10 may generate a baseband signal of an uplink physical channel, where a transport block delivered from a higher layer on the UL-SCH may be mapped to the uplink physical channel.

For example, the physical layer processing unit 10 may generate a baseband signal for the uplink physical signal.

For example, the physical layer processing unit 10 may attempt to detect information transmitted by the downlink physical channel. Here, the transport block of the information transmitted by the downlink physical channel may be delivered to higher layers on the DL-SCH.

For example, the physical layer processing unit 10 may attempt to detect information transmitted by a downlink physical signal.

The upper layer processing unit 14 performs some or all of the processing of the MAC (Medium Access Control) layer, Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer, and RRC layer.

The media access control layer processing unit (MAC layer processing unit) 15 performs MAC layer processing.

The radio resource control layer processing unit 16 performs RRC layer processing.

The radio resource control layer processing unit 16 may manage RRC parameters transmitted from the base station device 3. For example, the radio resource control layer processing unit 16 may acquire RRC parameters contained in an RRC message on a certain logical channel and set the acquired RRC parameters in a memory area of the terminal device 1. The RRC parameters set in the memory area of the terminal device 1 may be provided to a lower layer.

The radio resource control layer processing unit 16 may include functional information generated based on the functions provided by the terminal device 1 in an RRC message and transmit it to the base station device 3.

The physical layer processing unit 10 may perform some or all of the modulation processing, encoding processing, and transmission processing. The physical layer processing unit 10 may generate a physical signal based on some or all of the encoding processing, modulation processing, and baseband signal generation processing for the transport block. The physical layer processing unit 10 may place the physical signal in a certain BWP. The physical layer processing unit 10 may transmit the generated physical signal.

The physical layer processing unit 10 may perform either or both of demodulation and decoding. The physical layer processing unit 10 may deliver transport blocks of information detected based on the demodulation and decoding processes of the received physical signal to higher layers on the DL-SCH.

If carrier sensing is required in the band of the serving cell, the physical layer processing unit 10 may perform carrier sensing prior to transmitting the physical signal.

The RF unit 12 converts the signal received via the antenna unit 11 into a baseband signal.
The RF unit 12 outputs the baseband signal to the baseband unit 13.

The baseband unit 13 may digitize the baseband signal input from the RF unit 12. The baseband unit 13 derives a CP (Cy
The baseband unit 13 may perform a fast Fourier transform (FFT) on the baseband signal from which the CP has been removed, to extract a signal in the frequency domain.

The baseband unit 13 may generate a baseband signal by performing an Inverse Fast Fourier Transform (IFFT) on the physical signal. The baseband unit 13 may add a CP to the generated baseband signal. The baseband unit 13 may convert the baseband signal to which the CP has been added into an analog signal. The baseband unit 13 may output the analog baseband signal to the RF unit 12.

The RF unit 12 may remove unnecessary frequency components from the baseband signal input from the baseband unit 13. The RF unit 12 may upconvert the baseband signal to a carrier frequency to generate an RF signal. The RF unit 12 may transmit the RF signal via the antenna unit 31. The RF unit 12 may also have a function for controlling transmission power.

The physical signals are explained below.

Physical signal is a general term for downlink physical channel, downlink physical signal, uplink physical channel, and uplink physical channel. Physical channel is a general term for downlink physical channel and uplink physical channel. Physical signal is a general term for downlink physical signal and uplink physical signal.

The uplink physical channel may correspond to a set of resource elements that convey information generated in a higher layer. The uplink physical channel may be a physical channel used in an uplink component carrier. The uplink physical channel may be transmitted by the physical layer processing unit 10. The uplink physical channel may be received by the physical layer processing unit 30. In the uplink of the wireless communication system according to one aspect of the present embodiment, some or all of the following uplink physical channels may be used.
・PUCCH (Physical Uplink Control CHannel)
・PUSCH (Physical Uplink Shared CHannel)
・PRACH (Physical Random Access CHannel)

The PUCCH may be transmitted to deliver, transmit, or convey uplink control information (UCI). The uplink control information may be mapped to the PUCCH. The physical layer processing unit 10 may transmit the PUCCH in which the uplink control information is mapped. The physical layer processing unit 30 may receive the PUCCH in which the uplink control information is mapped.

Uplink control information (uplink control information bits, uplink control information sequence, uplink control information type) includes some or all of the channel state information (CSI), scheduling request (SR), and hybrid automatic repeat request ACKnowledgement (HARQ-ACK) information.

Channel state information is also referred to as channel state information bits or channel state information sequences. Scheduling requests are also referred to as scheduling request bits or scheduling request sequences. HARQ-ACK information is also referred to as HARQ-ACK information bits or HARQ-ACK information sequences.

The HARQ-ACK information may be configured by HARQ-ACK bits corresponding to a transport block (TB). A HARQ-ACK bit may indicate an acknowledgement (ACK) or a negative acknowledgement (NACK) corresponding to the transport block. An ACK may indicate that the decoding of the transport block has been successfully completed. A NACK may indicate that the decoding of the transport block has not been successfully completed. The HARQ-ACK information may include one or more HARQ-ACK bits.

HARQ-ACK for a transport block is also referred to as HARQ-ACK for a PDSCH. Here, "HARQ-ACK for a PDSCH" refers to a HARQ-ACK for a transport block included in the PDSCH.

The scheduling request may be used to request UL-SCH resources for an initial transmission. The scheduling request bit may be used to indicate either a positive SR or a negative SR. When the scheduling request bit indicates a positive SR, this is also referred to as "a positive SR is transmitted." A positive SR may indicate that UL-SCH resources for the initial transmission are requested by the media access control layer processing unit 15. When the scheduling request bit indicates a negative SR, this is also referred to as "a negative SR is transmitted." A negative SR may indicate that UL-SCH resources for the initial transmission are not requested by the media access control layer processing unit 15.

The channel state information may include some or all of a Channel Quality Indicator (CQI), a Precoder Matrix Indicator (PMI), and a Rank Indicator (RI). The CQI is an indicator related to the quality of the propagation path (e.g., propagation strength) or the quality of the physical channel, and the PMI is an indicator related to the precoder. The RI is an indicator related to the transmission rank (or the number of transmission layers).

Channel state information is an indicator related to the reception state of a physical signal (e.g., CSI-RS) used for channel measurement. The value of the channel state information may be determined by the terminal device 1 based on the reception state assumed by the physical signal used for channel measurement. Channel measurement may include interference measurement.

The PUCCH may be accompanied by a certain PUCCH format. Here, the PUCCH format may be the format of the physical layer processing of the PUCCH. The PUCCH format may also be the format of the information transmitted using the PUCCH.

The PUSCH may be transmitted to transmit uplink control information and/or a transport block. The PUSCH may be used to transmit uplink control information and/or a transport block. The terminal device 1 may transmit a PUSCH in which uplink control information and/or a transport block are allocated. The base station device 3 may receive a PUSCH in which uplink control information and/or a transport block are allocated.

The PRACH may be transmitted to convey the index of the random access preamble. The terminal device 1 may transmit the PRACH. The base station device 3 may receive the PRACH. The terminal device 1 may transmit the random access preamble on the PRACH. The base station device 3 may receive the random access preamble on the PRACH.

The uplink physical signal may correspond to a set of resource elements. The uplink physical signal does not have to be used to transmit information generated in a higher layer. The uplink physical signal may be used to transmit information generated in the physical layer. The uplink physical signal may be a physical signal used in an uplink component carrier. The physical layer processing unit 10 may transmit the uplink physical signal. The physical layer processing unit 30 may receive the uplink physical signal. In the uplink of the wireless communication system according to one aspect of the present embodiment, some or all of the following uplink physical signals may be used.
・UL DMRS (UpLink Demodulation Reference Signal)
・SRS (Sounding Reference Signal)
・UL PTRS (UpLink Phase Tracking Reference Signal)

UL DMRS is a general term for DMRS for PUSCH and DMRS for PUCCH.

The set of antenna ports for DMRS for PUSCH (DMRS associated with PUSCH, DMRS included in PUSCH, DMRS corresponding to PUSCH) may be determined based on the set of antenna ports for the PUSCH. For example, the set of antenna ports for DMRS for PUSCH may be the same as the set of antenna ports for the PUSCH.

The propagation path of the PUSCH may be estimated from the DMRS for the PUSCH.

The set of antenna ports for DMRS for PUCCH (DMRS associated with PUCCH, DMRS included in PUCCH, DMRS corresponding to PUCCH) may be the same as the set of antenna ports for PUCCH.

The propagation path of the PUCCH may be estimated from the DMRS for that PUCCH.

The downlink physical channel may correspond to a set of resource elements that convey information generated in a higher layer. The downlink physical channel may be a physical channel used in a downlink component carrier. The physical layer processing unit 30 may transmit the downlink physical channel. The physical layer processing unit 10 may receive the downlink physical channel. In the downlink of the wireless communication system according to one aspect of the present embodiment, some or all of the following downlink physical channels may be used.
・PBCH (Physical Broadcast Channel)
・PDCCH (Physical Downlink Control Channel)
・PDSCH (Physical Downlink Shared Channel)

The PBCH may be transmitted to convey one or both of the MIB (Master Information Block) and physical layer control information. Here, physical layer control information is information generated in the physical layer. The MIB is an RRC message delivered from higher layers on the BCCH (Broadcast Control Channel).

The PDCCH may be transmitted to convey downlink control information (DCI). The downlink control information may be allocated to the PDCCH. The terminal device 1 may receive the PDCCH in which the downlink control information is allocated. The base station device 3 may transmit the PDCCH in which the downlink control information is allocated.

The downlink control information may be transmitted in a DCI format.
The format may be interpreted as a form of downlink control information, and the DCI format may be interpreted as a set of downlink control information set to a certain downlink control information form.

The base station device 3 may notify the terminal device 1 of downlink control information using a PDCCH with a DCI format. Here, the terminal device 1 may monitor the PDCCH to acquire the downlink control information. Unless otherwise specified, the DCI format and downlink control information may be described as equivalent. For example, the base station device 3 may include the downlink control information in a DCI format and transmit it to the terminal device 1. Furthermore, the terminal device 1 may control the physical layer processing unit 10 using the downlink control information included in the detected DCI format.

DCI format 0_0, DCI format 0_1, DCI format 1_0, and DCI format 1_1 are DCI formats. The uplink DCI format is a general term for DCI format 0_0 and DCI format 0_1. The downlink DCI format is a general term for DCI format 1_0 and DCI format 1_1.

DCI format 0_0 is used for scheduling a PUSCH located in a certain cell, and may include some or all of fields 1A to 1E.
1A) Identifier field for DCI formats
1B) Frequency domain resource assignment field
field)
1C) Time Domain Resource Assignment Field
1D) Frequency hopping flag field
1E) MCS field (Modulation and Coding Scheme field)

The DCI format specification field may indicate whether the DCI format including the DCI format specification field is an uplink DCI format or a downlink DCI format. That is, the DCI format specification field may be included in both the uplink DCI format and the downlink DCI format. Here, the DCI format specification field included in DCI format 0_0 may indicate 0.

The frequency domain resource allocation field included in DCI format 0_0 may be used to indicate the allocation of frequency resources for the PUSCH scheduled by DCI format 0_0.

The time domain resource allocation field included in DCI format 0_0 may be used to indicate the allocation of time resources for the PUSCH scheduled by DCI format 0_0.

The frequency hopping flag field may be used to indicate whether frequency hopping is applied to the PUSCH scheduled by DCI format 0_0.

The MCS field included in DCI format 0_0 may be used to indicate one or both of a modulation scheme for a PUSCH scheduled by DCI format 0_0 and a target coding rate scheduled by DCI format 0_1. The target coding rate may be a target coding rate for a transport block assigned to the PUSCH. The size of the transport block (TBS) assigned to the PUSCH may be determined based on part or all of the target coding rate and the modulation scheme for the PUSCH.

DCI format 0_0 may not include fields used for CSI requests.

DCI format 0_0 may not include a carrier indicator field. In other words, the serving cell to which the uplink component carrier on which the PUSCH scheduled by DCI format 0_0 is allocated may be the same as the serving cell of the downlink component carrier on which the PDCCH including DCI format 0_0 is allocated. Based on detecting DCI format 0_0 on a downlink component carrier of a serving cell, the terminal device 1 may recognize that the PUSCH scheduled by DCI format 0_0 is to be allocated on the uplink component carrier of the serving cell.

DCI format 0_0 may not include a BWP field. Here, DCI format 0_0 may be a DCI format for scheduling a PUSCH without changing the active uplink BWP. Based on detecting DCI format 0_0 used for scheduling a PUSCH, the terminal device 1 may recognize that the PUSCH will be transmitted without switching the active uplink BWP.

DCI format 0_1 is used for scheduling a PUSCH allocated to a certain cell, and is configured to include some or all of fields 2A to 2H.
2A) DCI format specific field 2B) Frequency domain resource allocation field 2C) Uplink time domain resource allocation field 2D) Frequency hopping flag field 2E) MCS field 2F) CSI request field
2G) BWP field
2H) Carrier Indicator Field

The DCI format specific field included in DCI format 0_1 may indicate 0.

The frequency domain resource allocation field included in DCI format 0_1 may be used to indicate the allocation of frequency resources for the PUSCH scheduled by DCI format 0_1.

The time domain resource allocation field included in DCI format 0_1 may be used to indicate the allocation of time resources for the PUSCH scheduled by DCI format 0_1.

The MCS field included in DCI format 0_1 may be used to indicate one or both of the modulation scheme for the PUSH scheduled by DCI format 0_1 and the target coding rate for the PUSH scheduled by DCI format 0_1.

The BWP field of DCI format 0_1 may be used to indicate the uplink BWP in which the PUSCH scheduled by DCI format 0_1 is allocated. In other words, DCI format 0_1 may or may not involve a change in the active uplink BWP. The terminal device 1 may recognize the uplink BWP in which the PUSCH is allocated based on detecting DCI format 0_1 used for scheduling the PUSCH.

DCI format 0_1 that does not include a BWP field may be a DCI format that schedules a PUSCH without changing the active uplink BWP. Based on detecting DCI format 0_1 that is used for scheduling a PUSCH and does not include a BWP field, the terminal device 1 may recognize that the PUSCH will be transmitted without switching the active uplink BWP.

If DCI format 0_1 includes a BWP field but the terminal device 1 does not support the BWP switching function using DCI format 0_1, the BWP field may be ignored by the terminal device 1. In other words, a terminal device 1 that does not support the BWP switching function may recognize that it will transmit the PUSCH without switching the active uplink BWP based on detecting DCI format 0_1 that is used for PUSCH scheduling and includes a BWP field. Here, if the BWP switching function is supported, the radio resource control layer processing unit 16 may include function information indicating that the BWP switching function is supported in the RRC message.

The CSI request field may be used to indicate the reporting of CSI.

When DCI format 0_1 includes a carrier indicator field, the carrier indicator field may be used to indicate the serving cell of the uplink component carrier on which the PUSCH is allocated. Based on detecting DCI format 0_1 on the downlink component carrier of a serving cell, the terminal device 1 may recognize that the PUSCH scheduled by the DCI format 0_1 is allocated to the uplink component carrier of the serving cell indicated by the carrier indicator field included in the DCI format 0_1.

If DCI format 0_1 does not include a carrier indicator field, the serving cell to which the uplink component carrier on which the PUSCH scheduled by DCI format 0_1 is allocated may be the same as the serving cell of the downlink component carrier on which the PDCCH including DCI format 0_1 is allocated. Based on detecting DCI format 0_1 on a downlink component carrier of a serving cell, the terminal device 1 may recognize that the PUSCH scheduled by DCI format 0_1 is to be allocated on the uplink component carrier of the serving cell.

DCI format 1_0 is used for scheduling a PDSCH allocated to a certain cell, and is configured by including some or all of DCI format 3A to 3F.
3A) DCI format specific field 3B) Frequency domain resource allocation field 3C) Time domain resource allocation field 3D) MCS field 3E) PDSCH to HARQ feedback timing indicator field
3F) PUCCH resource indicator field

The DCI format specific field included in DCI format 1_0 may indicate 1.

The frequency domain resource allocation field included in DCI format 1_0 may be used to indicate the allocation of frequency resources for the PDSCH scheduled by that DCI format.

The time domain resource allocation field included in DCI format 1_0 may be used to indicate the allocation of time resources for the PDSCH scheduled by that DCI format.

The MCS field included in DCI format 1_0 may be used to indicate one or both of the modulation scheme for the PDSCH scheduled by that DCI format and the target coding rate for the PDSCH scheduled by that DCI format. The target coding rate may be the target coding rate for the transport block assigned to the PDSCH. The size of the transport block (TBS) assigned to the PDSCH may be determined based on one or both of the target coding rate and the modulation scheme for the PDSCH.

The PDSCH_HARQ feedback timing indication field may be used to indicate the offset from the slot containing the last OFDM symbol of the PDSCH to the slot containing the first OFDM symbol of the PUCCH.

The PUCCH resource indication field may be used to indicate the PUCCH resource.

DCI format 1_0 may not include a carrier indicator field. In other words, the downlink component carrier on which the PDSCH scheduled by DCI format 1_0 is allocated may be the same as the downlink component carrier on which the PDCCH including DCI format 1_0 is allocated. Based on detecting DCI format 1_0 on a certain downlink component carrier, the terminal device 1 may recognize that the PDSCH scheduled by DCI format 1_0 is to be allocated to that downlink component carrier.

DCI format 1_0 may not include a BWP field. Here, DCI format 1_0 may be a DCI format that schedules PDSCH without changing the active downlink BWP. Based on detecting DCI format 1_0 used for scheduling PDSCH, the terminal device 1 may recognize that it will receive the PDSCH without switching the active downlink BWP.

DCI format 1_1 is used for scheduling a PDSCH allocated to a certain cell, and is configured to include some or all of 4A to 4I.
4A) DCI format specific field 4B) Frequency domain resource allocation field 4C) Time domain resource allocation field 4E) MCS field 4F) PDSCH_HARQ feedback timing indication field 4G) PUCCH resource indication field 4H) BWP field 4I) Carrier indicator field

The DCI format specific field included in DCI format 1_1 may indicate 1.

The frequency domain resource allocation field included in DCI format 1_1 may be used to indicate the allocation of frequency resources for the PDSCH scheduled by DCI format 1_1.

The time domain resource allocation field included in DCI format 1_1 may be used to indicate the allocation of time resources for the PDSCH scheduled by DCI format 1_1.

The MCS field included in DCI format 1_1 may be used to indicate one or both of the modulation scheme for the PDSCH scheduled by DCI format 1_1 and the target coding rate for the PDSCH scheduled by DCI format 1_1.

If DCI format 1_1 includes a PDSCH_HARQ feedback timing indication field, the PDSCH_HARQ feedback timing indication field may be used to indicate the offset from the slot containing the last OFDM symbol of the PDSCH to the slot containing the first OFDM symbol of the PUCCH. If DCI format 1_1 does not include a PDSCH_HARQ feedback timing indication field, a parameter indicating the offset from the slot containing the last OFDM symbol of the PDSCH to the slot containing the first OFDM symbol of the PUCCH may be provided by the RRC layer.

The PUCCH resource indication field may be used to indicate the PUCCH resource.

The BWP field of DCI format 1_1 may be used to indicate the downlink BWP in which the PDSCH scheduled by DCI format 1_1 is allocated. In other words, DCI format 1_1 may or may not involve a change in the active downlink BWP. The terminal device 1 may recognize the downlink BWP in which the PDSCH is allocated based on detecting DCI format 1_1 used for scheduling the PDSCH.

The DCI format 1_1 that does not include a BWP field may be a DCI format that schedules the PDSCH without changing the active downlink BWP. The terminal device 1 may recognize that it will receive the PDSCH without switching the active downlink BWP based on detecting the DCI format 1_1 that is used for scheduling the PDSCH and does not include a BWP field.

If DCI format 1_1 includes a BWP field but the terminal device 1 does not support the BWP switching function using DCI format 1_1, the BWP field may be ignored by the terminal device 1. In other words, a terminal device 1 that does not support the BWP switching function may recognize that it will receive the PDSCH without switching the active downlink BWP based on detecting DCI format 1_1 that is used for PDSCH scheduling and includes a BWP field. Here, if the BWP switching function is supported, the radio resource control layer processing unit 16 may include function information indicating that the BWP switching function is supported in the RRC message.

When DCI format 1_1 includes a carrier indicator field, the carrier indicator field may be used to indicate the serving cell of the downlink component carrier on which the PDSCH scheduled by DCI format 1_1 is allocated. Based on detecting DCI format 1_1 on the downlink component carrier of a serving cell, the terminal device 1 may recognize that the PDSCH scheduled by DCI format 1_1 is allocated on the downlink component carrier of the serving cell indicated by the carrier indicator field included in DCI format 1_1.

If DCI format 1_1 does not include a carrier indicator field, the downlink component carrier on which the PDSCH scheduled by DCI format 1_1 is allocated may be the same as the downlink component carrier on which the PDCCH including DCI format 1_1 is allocated. Based on detecting DCI format 1_1 on a certain downlink component carrier, the terminal device 1 may recognize that the PDSCH scheduled by DCI format 1_1 is allocated to that downlink component carrier.

The PDSCH may be transmitted to transmit a transport block. The PDSCH may be used to transmit a transport block. The transport block may be allocated to the PDSCH. The base station device 3 may transmit a PDSCH in which a transport block is allocated. The terminal device 1 may receive a PDSCH in which a transport block is allocated.

The downlink physical signal may correspond to a set of resource elements. The downlink physical signal does not have to be used to transmit information generated in a higher layer. The downlink physical signal may be used to transmit information generated in the physical layer. The downlink physical signal may be a physical signal used in a downlink component carrier. The physical layer processing unit 10 may transmit the downlink physical signal. The physical layer processing unit 30 may receive the downlink physical signal. In the downlink of the wireless communication system according to one aspect of the present embodiment, at least some or all of the following downlink physical signals may be used.
・Synchronization signal (SS)
・DL DMRS (DownLink DeModulation Reference Signal)
・CSI-RS (Channel State Information-Reference Signal)
・DL PTRS (DownLink Phase Tracking Reference Signal)

The synchronization signal may be used by the terminal device 1 to synchronize one or both of the frequency domain and the time domain of the downlink. The synchronization signal is a general term for a PSS (Primary Synchronization Signal) and an SSS (Secondary Synchronization Signal).

The antenna ports for PSS, SSS, PBCH, and DMRS for PBCH may be the same.

The PBCH on which the PBCH symbols are transmitted at a certain antenna port may be estimated by the DMRS for the PBCH that is placed in the slot to which the PBCH is mapped and that is included in the SS/PBCH block to which the PBCH belongs.

DL DMRS is a general term for DMRS for PBCH, DMRS for PDSCH, and DMRS for PDCCH.

The set of antenna ports for DMRS for a PDSCH (DMRS associated with a PDSCH, DMRS included in a PDSCH, DMRS corresponding to a PDSCH) may be determined based on the set of antenna ports for the PDSCH. For example, the set of antenna ports for DMRS for a PDSCH may be the same as the set of antenna ports for the PDSCH.

The propagation path of a PDSCH may be estimated from the DMRS for that PDSCH. If the set of resource elements on which a certain PDSCH symbol is transmitted and the set of resource elements on which a DMRS symbol for that PDSCH is transmitted are included in the same precoding resource group (PRG), the PDSCH on which the PDSCH symbol is transmitted at a certain antenna port may be estimated from the DMRS for that PDSCH.

The antenna port for DMRS for PDCCH (DMRS associated with PDCCH, DMRS included in PDCCH, DMRS corresponding to PDCCH) may be the same as the antenna port for PDCCH.

The propagation path of a PDCCH may be estimated from the DMRS for that PDCCH. If the same precoder is applied (or is assumed to be applied, or is assumed to be applied) to the set of resource elements on which a certain PDCCH symbol is transmitted and the set of resource elements on which a DMRS symbol for that PDCCH is transmitted, the PDCCH on which the PDCCH symbol is transmitted at a certain antenna port may be estimated from the DMRS for that PDCCH.

BCH (Broadcast CHannel), UL-SCH (Uplink-Shared CHannel), and DL-SCH (Downlink-Shared CHannel) are transport channels.

The BCH of the transport layer may be mapped to the PBCH of the physical layer. That is, a transport block delivered from a higher layer on the BCH of the transport layer may be placed on the PBCH of the physical layer. The UL-SCH of the transport layer may be mapped to the PUSCH of the physical layer. That is, a transport block delivered from a higher layer on the UL-SCH of the transport layer may be placed on the PUSCH of the physical layer. The DL-SCH of the transport layer may be mapped to the PDSCH of the physical layer. That is, a transport block delivered from a higher layer on the DL-SCH of the transport layer may be placed on the PDSCH of the physical layer.

The transport layer may apply HARQ (Hybrid Automatic Repeat reQuest) to the transport block.

The BCCH (Broadcast Control CHannel), CCCH (Common Control CHannel), and DCCH (Dedicated Control CHannel) are logical channels. For example, the BCCH may be used to deliver RRC messages including an MIB or RRC messages including system information. The CCCH may also be used to transmit RRC messages including RRC parameters common to multiple terminal devices 1. Here, the CCCH may be used, for example, for terminal devices 1 that are not RRC-connected. The DCCH may also be used to transmit RRC messages dedicated to a certain terminal device 1. Here, the DCCH may be used, for example, for terminal devices 1 that are RRC-connected.

The BCCH may be mapped to the BCH or DL-SCH. In other words, RRC messages containing MIB information may be delivered on the BCH. RRC messages containing system information other than MIB may be delivered on the DL-SCH. The CCCH is mapped to the DL-SCH or UL-SCH. In other words, RRC messages mapped to the CCCH may be delivered on the DL-SCH or UL-SCH. The DCCH may be mapped to the DL-SCH or UL-SCH. In other words, RRC messages mapped to the DCCH may be delivered on the DL-SCH or UL-SCH.

The medium access control layer processing unit 15 may also perform a random access procedure.

Figure 5 is a diagram showing an example of a random access procedure performed by the media access control layer processing unit 15 according to one aspect of this embodiment. In the random access procedure shown in Figure 5, the media access control layer processing unit 15 may first perform judgment 5001. Here, judgment 5001 may determine the type of random access procedure. Furthermore, the type of random access procedure may be either a four-step random access procedure or a two-step random access procedure. In other words, judgment 5001 may select either a four-step random access procedure or a two-step random access procedure.

Here, "RA_TYPE" is a variable in which a value corresponding to the random access procedure selected in decision 5001 is stored. For example, the value corresponding to the four-step random access procedure may be "4STEP_RA", and the value corresponding to the two-step random access procedure may be "2STEP_RA". For example, if the media access control layer processing unit 15 selects the two-step random access procedure in decision 5001, "2STEP_RA" may be input into the variable "RA_TYPE".

In decision 5001, a determination regarding the strength of the downlink signal may be made. Here, the determination regarding the strength of the downlink signal in decision 5001 may be based at least on comparing the RSRP value of the downlink pathloss reference with a predetermined threshold #5001. For example, if the RSRP value of the downlink pathloss reference is greater than the predetermined threshold #5001, the media access control layer processing unit 15 may select a two-step random access procedure. Alternatively, if the RSRP value of the downlink pathloss reference is less than the predetermined threshold #5001, the media access control layer processing unit 15 may select a four-step random access procedure. Alternatively, if the RSRP value of the downlink pathloss reference is equal to the predetermined threshold #5001, the media access control layer processing unit 15 may select either the two-step random access procedure or the four-step random access procedure. For example, the downlink pathloss reference may be a physical signal used to determine a pathloss estimate used in uplink power control. The downlink path loss reference may also be the SS/PBCH block selected in the random access procedure.

If the media access control layer processing unit 15 selects the four-step random access procedure in decision 5001, the media access control layer processing unit 15 may perform random access resource selection process 5002. Here, in the random access resource selection process 5002, one or both of the following may be performed: selection of a random access preamble group and selection of a PRACH resource group.

Figure 6 is a diagram showing an example of the random access resource selection process 5002 performed by the media access control layer processing unit 15 according to one aspect of this embodiment. First, the media access control layer processing unit 15 may perform judgment 6001. Here, in judgment 6001, the media access control layer processing unit 15 may make a judgment regarding the strength of the downlink signal. For example, the judgment regarding the strength of the downlink signal in judgment 6001 may be made based on comparing the RSRP value of the downlink path loss reference with a predetermined threshold #6001. For example, if the RSRP value of the downlink path loss reference is smaller than the predetermined threshold #6001, the media access control layer processing unit 15 may proceed to judgment 6005. Also, if the RSRP value of the downlink path loss reference is greater than the predetermined threshold #6001, the media access control layer processing unit 15 may select judgment 6002. Furthermore, if the RSRP value of the downlink path loss reference is equal to the predetermined threshold #6001, the media access control layer processing unit 15 may proceed to either decision 6002 or decision 6005. Here, the downlink path loss reference may be a physical signal used to determine a path loss estimation value used in uplink power control. Alternatively, the downlink path loss reference may be an SS/PBCH block selected in the random access procedure.

If the media access control layer processing unit 15 proceeds to decision 6002, the media access control layer processing unit 15 may perform decision 6002. Here, in decision 6002, the media access control layer processing unit 15 may perform one or both of a decision regarding the strength of the downlink signal and a decision regarding the size of the uplink data. For example, the decision regarding the downlink signal strength in decision 6002 may be made based on comparing a path loss value measured based on a certain physical signal with threshold value #6002a. Here, threshold value #6002a may be a threshold determined based on one or more parameters. For example, the one or more parameters in decision 6002 may be parameters used for uplink transmission power control. For example, threshold #6002a may be determined based on the maximum transmit power PCMAX set in the serving cell in which the random access procedure is performed, the target received power of the random access preamble preambleReceivedTargetPower, the offset value msg3-DeltaPreamble between the target received power of the message 3 PUSCH and the target received power of the random access preamble, and the offset value messagePowerOffsetGroupB for decision 6002. For example, threshold #6002a may be determined by calculating PCMAX-preambleReceivedTargetPower-msg3-DeltaPreamble-messagePowerOffsetGroupB.

For example, the serving cell configured maximum transmit power PCMAX for performing the random access procedure may be a value set according to the frequency band (frequency position, band, frequency band) to which the serving cell belongs. Furthermore, the target received power of the random access preamble preambleReceivedTargetPower may be provided by the RRC layer. Furthermore, the offset value msg3-DeltaPreamble between the target received power of message 3 PUSCH and the target received power of the random access preamble may be provided by the RRC layer. Furthermore, the offset value messagePowerOffsetGroupB may be provided by the RRC layer.

For example, the determination regarding the size of the uplink data in decision 6002 may be made based on comparing the size of the uplink data with threshold #6002b. For example, in decision 6002, the uplink data may be the payload of a potential Message 3 PUSCH. Here, the payload of the potential Message 3 PUSCH may be a transport block placed on the Message 3 PUSCH expected to be transmitted in the random access procedure. Also, the payload of the potential Message 3 PUSCH may be one or both of a MAC SDU and a MAC subheader multiplexed into a transport block placed on the Message 3 PUSCH expected to be transmitted in the random access procedure. Here, the MAC SDU may be a MAC SDU delivered by a higher layer on the CCCH, or may be a MAC SDU delivered by a higher layer on a logical channel other than the CCCH. A MAC SDU delivered by a higher layer on the CCCH is also referred to as a CCCH SDU. Note that when the media access control layer processing unit 15 performs decision 6002, message 3 PUSCH transmission may not have been performed yet, so the decision is made based on the payload of the "potential" message 3 PUSCH.

For example, decision 6002 may be based on one or both of the truth or falsity of proposition 6002a and the truth or falsity of proposition 6002b. For example, the media access control layer processing unit 15 may proceed to process 6004 based on the determination that proposition 6002a is true. Alternatively, the media access control layer processing unit 15 may proceed to process 6004 based on the determination that proposition 6002b is true. Alternatively, the media access control layer processing unit 15 may proceed to process 6003 based on the determination that proposition 6002a is false and the determination that proposition 6002b is false.

For example, proposition 6002a may be that the size of the uplink data is greater than threshold #6002b and the path loss value is less than threshold #6002a. Alternatively, proposition 6002a may be that the size of the uplink data is not less than threshold #6002b and the path loss value is less than threshold #6002a. Alternatively, proposition 6002a may be that the size of the uplink data is greater than threshold #6002b and the path loss value is not greater than threshold #6002a. Alternatively, proposition 6002a may be that the size of the uplink data is not less than threshold #6002b and the path loss value is not greater than threshold #6002a.

The physical signal used in determining the downlink physical signal strength in process 6002 may be one SS/PBCH block selected from multiple SS/PBCH blocks. Here, the multiple SS/PBCH blocks may be multiple SS/PBCH blocks configured in the serving cell. The media access control layer processing unit 15 may select one SS/PBCH block from the multiple SS/PBCH blocks based on a comparison of the RSRP value for at least one SS/PBCH block with threshold #6002x. For example, if the RSRP value for at least one SS/PBCH block is greater than threshold #6002x, the media access control layer processing unit 15 may select one SS/PBCH block from among the SS/PBCH blocks whose RSRP values are greater than threshold #6002x. Furthermore, if the RSRP value for any SS/PBCH block is smaller than threshold #6002x, the media access control layer processing unit 15 may select one SS/PBCH block from multiple SS/PBCH blocks.

For example, threshold #6002x may be provided by a higher layer.

For example, proposition 6002b may be that a random access procedure is initiated for CCCH and the size of the uplink data is greater than threshold #6002b. Alternatively, proposition 6002b may be that a random access procedure is initiated for CCCH and the size of the uplink data is not less than threshold #6002b.

In process 6003, the media access control layer processing unit 15 may select random access preamble group A. Also, in process 6003, the media access control layer processing unit 15 may decide not to request the application of repeated transmission to the message 3 PUSCH.

In process 6004, the media access control layer processing unit 15 may select random access preamble group B. Also, in process 6004, the media access control layer processing unit 15 may decide not to request the application of repeated transmission to the message 3 PUSCH.

The terminal device 1 may notify the base station device 3 of information indicating whether to request the application of repeat transmission to the message 3 PUSCH using the PRACH transmitted during the random access procedure. For example, transmitting the PRACH based on the first PRACH resource group may correspond to requesting the application of repeat transmission to the message 3 PUSCH. Also, transmitting the PRACH based on the second PRACH resource group may correspond to not requesting the application of repeat transmission to the message 3 PUSCH.

In other words, when the media access control layer processing unit 15 requests the application of repeat transmission to the message 3 PUSCH, it may mean that the media access control layer processing unit 15 selects the first PRACH resource group. Also, when the media access control layer processing unit 15 does not request the application of repeat transmission to the message 3 PUSCH, it may mean that the media access control layer processing unit 15 selects the second PRACH resource group.

A PRACH resource group may be configured to include one or more PRACH resources. Here, one PRACH resource may be a resource identified by one or both of a time-frequency resource (e.g., a PRACH opportunity) and a random access preamble index.

Here, whether or not to configure random access preamble group B may be determined for each PRACH resource group. For example, random access preamble group B may not be configured for the first PRACH resource group. Also, a parameter indicating whether or not to configure random access preamble group B for the first PRACH resource group may be provided by the RRC layer.

For example, a parameter indicating whether or not to configure random access preamble group B for each PRACH resource group may be provided by the RRC layer.

In decision 6005, the media access control layer processing unit 15 may make a decision regarding the size of the uplink data. For example, the decision regarding the size of the uplink data in decision 6005 may be made based on comparing the size of the uplink data with threshold value #6002b.

For example, the medium access control layer processing unit 15 may proceed to decision 6007 if the random access procedure is initiated for the CCCH and the size of the uplink data is greater than threshold #6002b. Alternatively, the medium access control layer processing unit 15 may proceed to decision 6006 if the random access procedure is initiated for the CCCH and the size of the uplink data is less than threshold #6002b. Alternatively, the medium access control layer processing unit 15 may proceed to either step 6006 or step 6007 if the random access procedure is initiated for the CCCH and the size of the uplink data is equal to threshold #6002b. Alternatively, the medium access control layer processing unit 15 may proceed to step 6006 if the random access procedure is not initiated for the CCCH. In another example, the medium access control layer processing unit 15 may proceed to decision 6002 if the random access procedure is not initiated for the CCCH.

In process 6006, the media access control layer processing unit 15 may select random access preamble group A. Also, in process 6006, the media access control layer processing unit 15 may decide to request the application of repeated transmission to the message 3 PUSCH.

In judgment 6007, the media access control layer processing unit 6007 may determine whether random access preamble group B is configured for the first PRACH resource group. For example, if random access preamble group B is configured for the first PRACH resource group, the media access control layer processing unit 15 may proceed to processing 6009. Also, if random access preamble group B is not configured for the first PRACH resource group, the media access control layer processing unit 15 may proceed to processing 6008.

In process 6008, the media access control layer processing unit 15 may select random access preamble group B. Also, in process 6008, the media access control layer processing unit 15 may decide not to request the application of repeated transmission to the message 3 PUSCH.

In process 6009, the media access control layer processing unit 15 may select random access preamble group B. Also, in process 6009, the media access control layer processing unit 15 may decide to request the application of repeated transmission to message 3 PUSCH.

As described above, in the random access procedure, whether or not the media access control layer processing unit 15 requests the application of repeated transmission to message 3 PUSCH may be determined based on one or both of the RSRP value of the downlink path loss reference and whether or not random access preamble group B is configured for the first PRACH resource group.

For example, the media access control layer processing unit 15 may not request the application of repeat transmission to the message 3 PUSCH based on the RSRP value of the downlink path loss reference being greater than threshold #6001. Also, the media access control layer processing unit 15 may not request the application of repeat transmission to the message 3 PUSCH based on the RSRP value of the downlink path loss reference being not less than threshold #6001.

For example, the medium access control layer processing unit 15 may request the application of repeat transmission to the message 3 PUSCH based on the fact that the RSRP value of the downlink path loss reference is smaller than threshold #6001 and that random access preamble group B is configured for the first PRACH resource group. Also, the medium access control layer processing unit 15 may request the application of repeat transmission to the message 3 PUSCH based on the fact that the RSRP value of the downlink path loss reference is not greater than threshold #6001 and that random access preamble group B is configured for the first PRACH resource group.

For example, the media access control layer processing unit 15 may not request the application of repeat transmission to the message 3 PUSCH based on the fact that the RSRP value of the downlink path loss reference is smaller than threshold #6001 and that random access preamble group B is not configured for the first PRACH resource group. Also, the media access control layer processing unit 15 may not request the application of repeat transmission to the message 3 PUSCH based on the fact that the RSRP value of the downlink path loss reference is not greater than threshold #6001 and that random access preamble group B is not configured for the first PRACH resource group.

Here, the base station device 3 may set the information contained in message 2 PDSCH (random access response grant) based on whether or not a request has been transmitted from the terminal device 1.

For example, the media access control layer processing unit 15 may select one PRACH opportunity in the random access resource selection process 5002. Here, the media access control layer processing unit 15 may select one PRACH opportunity from among the PRACH opportunities associated with the PRACH resource group.

For example, the media access control layer processing unit 15 may select one random access preamble based on the selected PRACH resource group and the selected random access preamble group.

After performing process 5002, the medium access control layer processing unit 15 may perform process 5003. Here, process 5003 may include a process for transmitting a random access preamble and a process for receiving a random access response.

Here, the random access preamble transmission process may be a process of instructing the physical layer processing unit 10 to transmit one selected random access preamble in one PRACH opportunity selected by the medium access control layer processing unit 15. In other words, the medium access control layer processing unit 15 may instruct the physical layer processing unit 10 to transmit one selected random access preamble in one selected PRACH opportunity.

Furthermore, the process of receiving a random access response may be a process in which the media access control layer processing unit 15 monitors the PDCCH for a predetermined period of time. Here, the predetermined period is also referred to as the random access response window. Here, even if the PDCCH monitoring is actually performed by the physical layer processing unit 10, the monitoring may be considered to have been performed by the media access control layer processing unit 15.

For example, the media access control layer processing unit 15 may start the random access response window at the first PDCCH monitoring occasion from the end of the transmission of the random access preamble, where a parameter (ra-ResponseWindow) determining the duration of the random access response window may be provided by the RRC layer.

For example, different parameters may be used to determine the duration of the random access response window depending on whether or not the application of repeated transmission to the message 3 PUSCH is requested. For example, a first parameter and a second parameter may be provided by the RRC layer. Here, if the application of repeated transmission to the message 3 PUSCH is requested, the medium access control layer processing unit 15 may determine the duration of the random access response window based on the value indicated by the first parameter. Also, if the application of repeated transmission to the message 3 PUSCH is not requested, the medium access control layer processing unit 15 may determine the duration of the random access response window based on the value indicated by the second parameter.

For example, if a random access response including a field indicating the index of the selected random access preamble is received during the duration of the random access response window, the media access control layer processing unit 15 may consider the reception of the random access response to have been successfully completed. On the other hand, if the random access response window has expired and a random access response including a field indicating the index of the selected random access preamble has not been received, the media access control layer processing unit 15 may consider the reception of the random access response to have been unsuccessful.

If the random access response is not successfully received, the media access control layer processing unit 15 may increment the preamble transmission counter. If the value of the preamble transmission counter reaches a predetermined value #5003, the media access control layer processing unit 15 may notify the upper layer that a problem has occurred in the implementation of the random access procedure (random access problem).

Here, the predetermined value #5003 may be determined by a parameter provided by the RRC layer. For example, different parameters may be used to determine the predetermined value #5003 depending on whether or not the application of repeated transmission to the message 3 PUSCH is requested. For example, a third parameter and a fourth parameter may be provided by the RRC layer. Here, if the application of repeated transmission to the message 3 PUSCH is requested, the medium access control layer processing unit 15 may determine the predetermined value #5003 based on the value indicated by the third parameter. Also, if the application of repeated transmission to the message 3 PUSCH is not requested, the medium access control layer processing unit 15 may determine the predetermined value #5003 based on the value indicated by the fourth parameter.

If the random access response has been successfully received, the media access control layer processing unit 15 may process the uplink grant (random access response grant) included in the random access response. In processing the uplink grant, the physical layer processing unit 10 may be instructed to transmit message 3 PUSCH.

For example, if the random access response has been successfully received, the media access control layer processing unit 15 may proceed to process 5004. Here, process 5004 may include contention resolution processing.

For example, in the collision resolution process, a contention window may be initiated each time a message 3 PUSCH transmission occurs. During the duration of the contention window, the medium access control layer processing unit 15 may monitor the PDCCH.

For example, if a PDCCH detected during the contention window duration and the collision resolution identifier included in a transport block included in a PDSCH scheduled by that PDCCH is equal to the value of the collision resolution identifier transmitted in message 3 PUSCH, the media access control layer processing unit 15 may consider collision resolution to have been successfully completed.

For example, if no PDSCH including a collision resolution identifier indicating a value equal to the value of the collision resolution identifier transmitted in message 3 PUSCH is detected during the duration of the contention window, the media access control layer processing unit 15 may determine that collision resolution has not been completed successfully. For example, if the contention window expires, the media access control layer processing unit 15 may determine that collision resolution has not been completed successfully.

For example, if collision resolution is not completed successfully, the media access control layer processing unit 15 may increment the preamble transmission counter.

If the media access control layer processing unit 15 selects the two-step random access procedure in decision 5001, the media access control layer processing unit 15 may perform random access resource selection process 5005. Here, in the random access resource selection process 5005, a random access preamble group may be selected.

In the random access resource selection process 5005, the media access control layer processing unit 15 may perform judgment 5005. Here, in judgment 5005, the media access control layer processing unit 15 may perform one or both of a judgment regarding the strength of the downlink signal and a judgment regarding the size of the uplink signal.

For example, the determination of downlink signal strength in decision 5005 may be made based on comparing a path loss value measured based on a certain physical signal with threshold value #5005a. Here, threshold value #5005a may be a threshold determined based on one or more parameters. For example, the one or more parameters in decision 5005 may be parameters used for uplink transmission power control. For example, threshold value #5005a may be determined based on the serving cell configured maximum transmission power PCMAX in which the random access procedure is performed, the target received power of the random access preamble msgA-preambleReceivedTargetPower, the offset value msgA-DeltaPreamble between the target received power of the message A PUSCH and the target received power of the random access preamble, and the offset value messagePowerOffsetGroupB for decision 5005. For example, threshold #5005a may be determined by calculating PCMAX-msgA-preambleReceivedTargetPower-msgA-DeltaPreamble-messagePowerOffsetGroupB.

For example, the target received power of the random access preamble, msgA-preambleReceivedTargetPower, may be provided by the RRC layer. Also, the offset value msgA-DeltaPreamble between the target received power of the message A PUSCH and the target received power of the random access preamble may be provided by the RRC layer.

For example, the determination regarding the size of the uplink data in decision 5005 may be based on comparing the size of the uplink data with threshold # 5005b. For example, the uplink data in decision 5005 may be the payload of a potential Message A PUSCH. For example, the payload of a potential Message A PUSCH may be a transport block to be placed in a Message A PUSCH expected to be transmitted in a random access procedure.
The payload of the PUSCH may be one or both of a MAC SDU and a MAC subheader multiplexed into a transport block allocated to a message A PUSCH expected to be transmitted in the random access procedure. Note that, when the medium access control layer processing unit 15 performs decision 5005, the message A PUSCH may not have been transmitted yet, so the decision is made based on the payload of the “potential” message A PUSCH.

For example, judgment 5005 may be a judgment based on one or both of the truth or falsity of proposition 5005a and the truth or falsity of proposition 5005b. For example, the medium access control layer processing unit 15 may select random access preamble group A based on the judgment that proposition 5005a is true. Furthermore, the medium access control layer processing unit 15 may select random access preamble group A based on the judgment that proposition 5005b is true. Furthermore, the medium access control layer processing unit 15 may select random access preamble group B based on the judgment that proposition 5005a is false and the judgment that proposition 5005b is false.

For example, proposition 5005a may be that the size of uplink data is greater than threshold #5005b and the path loss value is less than threshold #5005a. Alternatively, proposition 5005a may be that the size of uplink data is not less than threshold #5005b and the path loss value is less than threshold #5005a. Alternatively, proposition 5005a may be that the size of uplink data is greater than threshold #5005b and the path loss value is not greater than threshold #5005a. Alternatively, proposition 5005a may be that the size of uplink data is not less than threshold #5005b and the path loss value is not greater than threshold #5005a.

For example, proposition 5005b may be that a random access procedure is initiated for CCCH and the size of the uplink data is greater than threshold #5005b. Alternatively, proposition 5005b may be that a random access procedure is initiated for CCCH and the size of the uplink data is not less than threshold #5005b.

In contention-based two-step random access, the media access control layer processing unit 15 may perform decision 5005. On the other hand, in non-contention-based two-step random access, the media access control layer processing unit 15 may not perform decision 5005. Here, if decision 5005 is not performed in non-contention-based two-step random access, the media access control layer processing unit 15 may proceed to process 5006 after performing decision 5001.

After performing process 5005, the media access control layer processing unit 15 may perform process 5006. Here, process 5006 may include a process for sending message A and a process for receiving message B.

Here, message A is a term that includes the random access preamble and message A PUSCH. In other words, the process of transmitting message A may include the process of transmitting the random access preamble and the process of transmitting message A PUSCH.

In addition, the message B reception process may be a process in which the media access control layer processing unit 15 monitors the PDCCH for a predetermined period of time. Here, the predetermined period is also referred to as the message B window.

For example, the media access control layer processing unit 15 may start the message B window at the first PDCCH monitoring occasion after the end of the transmission of the random access preamble. Here, the parameter (msgB-ResponseWindow) that determines the duration of the message B window may be provided by the RRC layer.

For example, if message B including a first data unit is received during the duration of the message B window, and a random access response including a field indicating the index of the selected random access preamble is received, the media access control layer processing unit 15 may consider that reception of the random access response has been successfully completed. If reception of the random access response has been successfully completed, the media access control layer processing unit 15 may proceed to processing 5004.

Here, the data unit may be in a data format or form recognized by the MAC layer.

For example, if message B including a second data unit different from the first data unit is received during the duration of the message B window, and the collision resolution identifier included in the second data unit is equal to the value of the collision resolution identifier transmitted in the message A PUSCH, the media access control layer processing unit 15 may consider reception of message B to be successfully completed. If reception of message B is successfully completed, the media access control layer processing unit 15 may consider reception of the random access response to be successfully completed. Also, if reception of message B is successfully completed, the media access control layer processing unit 15 may consider the random access procedure to be successfully completed.

If the message B window expires and the reception of the random access response is not completed successfully, the media access control layer processing unit 15 may increment the preamble transmission counter. If the value of the preamble transmission counter reaches a predetermined value #5006, the media access control layer processing unit 15 may change "RA_TYPE" to "4STEP_RA". Also, if the value of the preamble transmission counter reaches a predetermined value #5006, the media access control layer processing unit 15 may proceed to process 5002.

When "RA_TYPE" is changed from "2STEP_RA" to "4STEP_RA" in the random access procedure, the medium access control layer processing unit 15 may perform random access resource selection process 5002X instead of random access resource selection process 5002. Here, random access resource selection process 5002X may select one or both of a random access preamble group and a PRACH resource group.

In the random access resource selection process 5002X, the media access control layer processing unit 15 may perform decision 5002X. Here, in decision 5002X, the media access control layer processing unit 15 may perform one or both of a decision regarding the strength of the downlink signal and a decision regarding the selection of a random access preamble group. For example, the decision regarding the strength of the downlink signal in decision 5002X may be made based on comparing the RSRP value of the downlink path loss reference with a predetermined threshold #5002X. Here, the downlink path loss reference may be a physical signal used to determine a path loss estimation value used in uplink power control. Alternatively, the downlink path loss reference may be an SS/PBCH block selected in the random access procedure.

For example, in the determination regarding the selection of a random access preamble group in decision 5002X, the media access control layer processing unit 15 may determine whether or not a random access preamble group has already been selected. For example, in decision 5002X, it may be determined whether or not a random access preamble group has already been selected in a two-step random access performed prior to decision 5002X.

For example, if the RSRP value of the downlink path loss reference is greater than a predetermined threshold #5002X and a random access preamble group has not yet been selected, the media access control layer processing unit 15 may perform process 5012X. Also, if the RSRP value of the downlink path loss reference is not less than the predetermined threshold #5002X and a random access preamble group has not yet been selected, the media access control layer processing unit 15 may perform process 5012X. Also, if the RSRP value of the downlink path loss reference is greater than the predetermined threshold #5002X and a random access preamble group has already been selected, the media access control layer processing unit 15 may perform process 5022X. Also, if the RSRP value of the downlink path loss reference is not less than the predetermined threshold #5002X and a random access preamble group has already been selected, the media access control layer processing unit 15 may perform process 5022X. Furthermore, if the RSRP value of the downlink path loss reference is smaller than the predetermined threshold #5002X and a random access preamble group has not yet been selected, the media access control layer processing unit 15 may perform operation 5032X. Furthermore, if the RSRP value of the downlink path loss reference is not greater than the predetermined threshold #5002X and a random access preamble group has not yet been selected, the media access control layer processing unit 15 may perform operation 5032X. Furthermore, if the RSRP value of the downlink path loss reference is smaller than the predetermined threshold #5002X and a random access preamble group has already been selected, the media access control layer processing unit 15 may perform operation 5042X. Furthermore, if the RSRP value of the downlink path loss reference is not greater than the predetermined threshold #5002X and a random access preamble group has already been selected, the media access control layer processing unit 15 may perform operation 5042X. Furthermore, if the RSRP value of the downlink path loss reference is not greater than the predetermined threshold #5002X and a random access preamble group has already been selected, the media access control layer processing unit 15 may perform operation 5042X.

For example, in the random access resource selection process 5012X, one or both of a determination regarding the setting of random access preamble group B and a determination regarding the payload size of message A may be performed. Here, in the determination regarding the setting of random access preamble group B in the random access resource selection process 5012X, the medium access control layer processing unit 15 may determine whether random access preamble group B is set for the second PRACH resource group. Furthermore, the determination regarding the payload size of message A in the random access resource selection process 5012X may be made based on a comparison between the payload size of message A and a threshold value 5012X. For example, the payload size may be the size of the payload transport block.

For example, in random access resource selection process X, the medium access control layer processing unit 15 may select random access preamble group B based on the fact that proposition 5012Xa is true and proposition 5012Xb is true. Also, in random access resource selection process 5012X, random access preamble group A may be selected based on the fact that proposition 5012Xa is false. Also, in random access resource selection process 5012X, random access preamble group A may be selected based on the fact that proposition 5012Xb is false.

For example, proposition 5012Xa may be that random access preamble group B is configured for the second PRACH resource group.

Proposition 5012Xb may also be that the size of the transport block of the payload of message A corresponds to the size of the transport block of the payload of message A for random access preamble group B. Here, the fact that the size of the transport block of the payload of message A corresponds to the size of the transport block of the payload of message A for random access preamble group B may mean that the size of the transport block of the payload of message A is greater than threshold value #5005b. Proposition 5012Xb may also be that the size of the transport block of the payload of message A corresponds to the size of the transport block of the payload of message A for random access preamble group B may mean that the size of the transport block of the payload of message A is not smaller than threshold value #5005b. Proposition 5012Xb may also be that the size of the transport block of the payload of message A corresponds to the size of the transport block of the payload of message A for random access preamble group B may mean that the size of the transport block of the payload of message A is greater than threshold value #6002b. Furthermore, the size of the transport block of the payload of message A corresponding to the size of the transport block of the payload of message A related to random access preamble group B may be such that the size of the transport block of the payload of message A is not smaller than threshold value #6002b.

For example, in the random access resource selection process 5022X, the media access control layer processing unit 15 may select the same random access preamble group as the already selected random access preamble group.

Figure 7 is a diagram showing an example of the random access resource selection process 5032X performed by the media access control layer processing unit 15 according to one aspect of this embodiment. First, in the random access resource selection process 5032X, the media access control layer processing unit 15 may perform decision 7001. Here, decision 7001 may be a decision regarding random access preamble group B configuration. For example, in decision 7001, the media access control layer processing unit 15 may proceed to decision 7005 based on the fact that random access preamble group B is not configured for the first PRACH resource group. Also, in decision 7001, the media access control layer processing unit 15 may proceed to decision 7002 based on the fact that random access preamble group B is configured for the first PRACH resource group.

For example, the media access control layer processing unit 15 may determine whether proposition 5012Xb is true or false in decision 7002. For example, the media access control layer processing unit 15 may proceed to process 7004 based on the fact that proposition 5012Xb is true in decision 7002. Alternatively, the media access control layer processing unit 15 may proceed to process 7003 based on the fact that proposition 5012Xb is false in decision 7002.

In process 7003, the media access control layer processing unit 15 may select random access preamble group A. Also, in process 7003, the media access control layer processing unit 15 may decide not to request the application of repeated transmission to the message 3 PUSCH.

In process 7004, the media access control layer processing unit 15 may select random access preamble group B. Also, in process 7004, the media access control layer processing unit 15 may decide not to request the application of repeated transmission to the message 3 PUSCH.

For example, the media access control layer processing unit 15 may determine whether proposition 5012Xb is true or false in judgment 7005. For example, the media access control layer processing unit 15 may proceed to process 7006 based on the fact that proposition 5012Xb is true in judgment 7005. Alternatively, the media access control layer processing unit 15 may proceed to process 7007 based on the fact that proposition 5012Xb is false in judgment 7005.

In process 7006, the media access control layer processing unit 15 may select random access preamble group A. Also, in process 7006, the media access control layer processing unit 15 may decide to request the application of repeated transmission to message 3 PUSCH.

In process 7007, the media access control layer processing unit 15 may select random access preamble group B. Also, in process 7007, the media access control layer processing unit 15 may decide not to request the application of repeated transmission to the message 3 PUSCH.

For example, whether or not to request repeated transmission for the PUSCH in message 3 may be determined based on one or both of the transport block size of the payload of message A and whether or not random access preamble group B is configured for the first PRACH resource group.

For example, in process 5042X, a determination regarding random access preamble group B configuration may be made. For example, in process 5042X, the media access control layer processing unit 15 may decide not to request the application of repeated transmission to the message 3 PUSCH based on the fact that random access preamble group B is not configured for the first PRACH resource group. Also, in process 5042X, the media access control layer processing unit 15 may decide to request the application of repeated transmission to the message 3 PUSCH based on the fact that random access preamble group B is configured for the first PRACH resource group.

Figure 8 is a diagram showing an example of a random access procedure performed by the media access control layer processing unit 15 according to one aspect of this embodiment. In the random access procedure shown in Figure 8, the media access control layer processing unit 15 may first perform decision 8001. Here, in decision 8001, the type of random access procedure may be determined. Furthermore, the type of random access procedure may be any of a four-step random access procedure without requesting the application of repeat transmission to the message 3 PUSCH, a four-step random access procedure with requesting the application of repeat transmission to the message 3 PUSCH, and a two-step random access procedure. In other words, in decision 8001, any of a four-step random access procedure without requesting the application of repeat transmission to the message 3 PUSCH, a four-step random access procedure with requesting the application of repeat transmission to the message 3 PUSCH, and a two-step random access procedure may be selected.

Here, "RA_TYPE" is a variable in which a value corresponding to the random access procedure selected in decision 8001 is stored. For example, the value corresponding to the four-step random access procedure without requesting the application of repeat transmission to the message 3 PUSCH may be "4STEP_RA", and the value corresponding to the two-step random access procedure may be "2STEP_RA". Also, the value corresponding to the four-step random access procedure with requesting the application of repeat transmission to the message 3 PUSCH may be "4STEP_RAreq". For example, if, in decision 8001, the medium access control layer processing unit 15 selects the four-step random access procedure with requesting the application of repeat transmission to the message 3 PUSCH, "4STEP_RAreq" may be input to the variable "RA_TYPE".

In decision 8001, a determination regarding the strength of the uplink signal may be made. Here, the determination regarding the strength of the downlink signal in decision 8001 may be based on one or both of comparing the RSRP value of the downlink path loss reference with a predetermined threshold #5001 and comparing the RSRP value of the downlink path loss reference with a predetermined threshold #8001. For example, if the RSRP value of the downlink path loss reference is greater than the predetermined threshold #5001, the media access control layer processing unit 15 may select a two-step random access procedure. Also, if the RSRP value of the downlink path loss reference is less than the predetermined threshold #8001, the media access control layer processing unit 15 may select a four-step random access procedure involving requesting the application of repeated transmission for message 3 PUSCH. Furthermore, if the RSRP value of the downlink path loss reference is smaller than predetermined threshold #5001 and larger than predetermined threshold #8001, the media access control layer processing unit 15 may select a four-step random access procedure that does not involve a request for repeat transmission for message 3 PUSCH. Furthermore, if the RSRP value of the downlink path loss reference is equal to predetermined threshold #5001, the media access control layer processing unit 15 may select either a two-step random access procedure or a four-step random access procedure that does not involve a request for repeat transmission for message 3 PUSCH. Furthermore, if the RSRP value of the downlink path loss reference is equal to predetermined threshold #8001, the media access control layer processing unit 15 may select either a four-step random access procedure that does not involve a request for repeat transmission for message 3 PUSCH or a four-step random access procedure that involves a request for repeat transmission for message 3 PUSCH.

If the media access control layer processing unit 15 selects a four-step random access procedure that does not request the application of repetitive transmission to the message 3 PUSCH in decision 8001, the media access control layer processing unit 15 may proceed to process 8002. Here, the media access control layer processing unit 15 may proceed to process 8002 and select a second PRACH resource group.

In process 8002, the media access control layer processing unit 15 may select a random access preamble group. For example, in process 8002, the media access control layer processing unit 15 may select random access preamble group B based on a determination that proposition 6002a is true. Also, in process 8002, the media access control layer processing unit 15 may select random access preamble group B based on a determination that proposition 6002b is true. Also, in process 8002, the media access control layer processing unit 15 may select random access preamble group A based on a determination that proposition 6002a is false and a determination that proposition 6002b is false.

Process 8003 is similar to process 5003, so a detailed explanation will be omitted.

For example, if the reception of the random access response in process 8003 is successfully completed, the media access control layer processing unit 15 may proceed to process 8004. Here, process 8004 may include a collision resolution process.

For example, in the collision resolution process, a contention window may be initiated each time a message 3 PUSCH transmission occurs. During the duration of the contention window, the medium access control layer processing unit 15 may monitor the PDCCH.

For example, if a PDCCH detected during the contention window duration and the collision resolution identifier included in a transport block included in a PDSCH scheduled by that PDCCH is equal to the value of the collision resolution identifier transmitted in message 3 PUSCH, the media access control layer processing unit 15 may consider collision resolution to have been successfully completed.

For example, if no PDSCH including a collision resolution identifier indicating a value equal to the value of the collision resolution identifier transmitted in message 3 PUSCH is detected during the duration of the contention window, the media access control layer processing unit 15 may determine that collision resolution has not been completed successfully. For example, if the contention window expires, the media access control layer processing unit 15 may determine that collision resolution has not been completed successfully.

For example, if collision resolution is not completed successfully, the media access control layer processing unit 15 may increment the preamble transmission counter.

For example, if collision resolution is not completed successfully, the media access control layer processing unit 15 may increment a request counter. If the request counter reaches a predetermined value #8004, the media access control layer processing unit 15 may recognize that the four-step random access procedure without requesting the application of repeated transmissions for message 3 PUSCH has failed.

For example, if the media access control layer processing unit 15 recognizes that the four-step random access procedure without requesting the application of repeat transmission for message 3 PUSCH has failed, the media access control layer processing unit 15 may proceed to process 8005.

For example, whether the media access control layer processing unit 15 proceeds to step 8005 depends on message 3
The determination may be based on some or all of the following: whether it has been recognized that the four-step random access procedure without requesting the application of repetitive transmission to the PUSCH has failed; whether the random access preamble group B has been configured for the first PRACH resource group; and whether the random access preamble group B has already been selected. Here, the medium access control layer processing unit 15 may proceed to process 8005 and change “RA_TYPE” from “4STEP_RA” to “4STEP_RAreq”.

For example, if the media access control layer processing unit 15 recognizes that the four-step random access procedure without a request for application of repetitive transmission to the message 3 PUSCH has failed, if the random access preamble group B has been configured for the first PRACH resource group, and if the random access preamble group B has been selected in process 8002, the media access control layer processing unit 15 may proceed to process 8005. Also, if the media access control layer processing unit 15 recognizes that the four-step random access procedure without a request for application of repetitive transmission to the message 3 PUSCH has failed, if the random access preamble group B has been configured for the first PRACH resource group, and if the random access preamble group A has been selected in process 8002, the media access control layer processing unit 15 may proceed to process 8005. Furthermore, if the media access control layer processing unit 15 recognizes that the four-step random access procedure without a request for application of repetitive transmission to the message 3 PUSCH has failed, if the random access preamble group B has not been configured for the first PRACH resource group, and if the random access preamble group B has been selected in process 8002, the media access control layer processing unit 15 does not need to proceed to process 8005. Furthermore, if the media access control layer processing unit 15 recognizes that the four-step random access procedure without a request for application of repetitive transmission to the message 3 PUSCH has failed, if the random access preamble group B has not been configured for the first PRACH resource group, and if the random access preamble group A has been selected in process 8002, the media access control layer processing unit 15 may proceed to process 8005.

Here, the predetermined value #8004 may be determined based on parameters provided by the RRC layer.

If the media access control layer processing unit 15 selects a four-step random access procedure involving requesting the application of repetitive transmission to the message 3 PUSCH in decision 8001, the media access control layer processing unit 15 may proceed to process 8005. Here, in process 8005, a random access preamble group may be selected. Here, the media access control layer processing unit 15 may proceed to process 8005 and select the first PRACH resource group.

In process 8005, the media access control layer processing unit 15 may select a random access preamble group. For example, if random access preamble group B is configured for the first PRACH resource group, in process 8005, selection of a random access preamble group based on a determination regarding the size of the uplink data may be performed. Here, the determination regarding the size of the uplink data in process 8005 may be based on comparing the size of the uplink data with threshold value #8005a. For example, in process 8005, the uplink data may be the payload of a potential message 3 PUSCH.

For example, in process 8005, the truth or falsity of proposition 8005 may be determined. For example, proposition 8005 may be that a random access procedure is initiated for CCCH and the size of uplink data is greater than threshold #8005. Also, proposition 8005 may be that a random access procedure is initiated for CCCH and the size of uplink data is not smaller than threshold #8005.

For example, if proposition 8005 is determined to be true, the medium access control layer processing unit 15 may select random access preamble group B. Also, if proposition 8005 is determined to be false, the medium access control layer processing unit 15 may select random access preamble group A.

For example, if random access preamble group B is configured for the first PRACH resource group, in operation 8005, the random access preamble group may be selected based on one or both of a determination of downlink signal strength and a determination regarding the size of uplink data. For example, the determination of downlink signal strength in operation 8005 may be based on comparing a path loss value measured based on a certain physical signal with threshold value 8005a. Here, threshold value 8005a may be a threshold determined based on one or more parameters. For example, the one or more parameters in operation 8005 may be parameters used for uplink transmission power control. For example, threshold value #8005a may be determined based on the maximum transmit power PCMAX set in the serving cell in which the random access procedure is performed, the target received power of the random access preamble preambleReceivedTargetPowerReq, the offset value msg3-DeltaPreambleReq between the target received power of the message 3 PUSCH and the target received power of the random access preamble, and the offset value messagePowerOffsetGroupBReq for decision 8005. For example, threshold value #8005a may be determined by calculating PCMAX-preambleReceivedTargetPowerReq-msg3-DeltaPreambleReq-messagePowerOffsetGroupBReq.

For example, the target received power of the random access preamble, preambleReceivedTargetPowerReq, may be provided by the RRC layer. Also, the offset value msg3-DeltaPreambleReq between the target received power of the message 3 PUSCH and the target received power of the random access preamble may be provided by the RRC layer. Also, the offset value messagePowerOffsetGroupBReq may be provided by the RRC layer.

For example, judgment 8005 may be a judgment based on one or both of the truth or falsity of proposition 8005 and the truth or falsity of proposition 8005a. For example, the medium access control layer processing unit 15 may select random access preamble group B based on the judgment that proposition 8005 is true. Also, the medium access control layer processing unit 15 may select random access preamble group B based on the judgment that proposition 8005a is true. Also, the medium access control layer processing unit 15 may select random access preamble group A based on the judgment that proposition 8005 is false and the judgment that proposition 8005a is false.

For example, proposition 8005a may be that the size of the uplink data is greater than threshold #8005 and the path loss value is less than threshold #8005a. Proposition 8005a may also be that the size of the uplink data is not less than threshold #8005 and the path loss value is less than threshold #8005a. Proposition 8005a may also be that the size of the uplink data is greater than threshold #8005 and the path loss value is not greater than threshold #8005a. Proposition 8005a may also be that the size of the uplink data is not less than threshold #8005 and the path loss value is not greater than threshold #8005a.

The physical signal used in determining the downlink physical signal strength in process 8005 may be one SS/PBCH block selected from multiple SS/PBCH blocks. Here, the multiple SS/PBCH blocks may be multiple SS/PBCH blocks configured in the serving cell. The media access control layer processing unit 15 may select one SS/PBCH block from the multiple SS/PBCH blocks based on a comparison of the RSRP value for at least one SS/PBCH block with threshold #8005x. For example, if the RSRP value for at least one SS/PBCH block is greater than threshold #8005x, the media access control layer processing unit 15 may select one SS/PBCH block from among the SS/PBCH blocks whose RSRP values are greater than threshold #8005x. Furthermore, if the RSRP value for any SS/PBCH block is smaller than threshold #8005x, the media access control layer processing unit 15 may select one SS/PBCH block from multiple SS/PBCH blocks.

For example, threshold #8005x may be provided by the RRC layer.

Process 8006 is similar to process 5003, so a detailed explanation will be omitted.

For example, if the reception of the random access response in step 8006 is successfully completed, the media access control layer processing unit 15 may proceed to step 8007. Here, step 8007 may include a collision resolution process.

For example, in the collision resolution process, a contention window may be initiated each time a message 3 PUSCH transmission occurs. During the duration of the contention window, the medium access control layer processing unit 15 may monitor the PDCCH.

For example, if repeated transmission is applied to the message 3 PUSCH, a contention window may be started for each repeated transmission of the message 3 PUSCH. Also, if repeated transmission is applied to the message 3 PUSCH, a contention window may be started for the first repeated transmission of the message 3 PUSCH, and a contention window may not be started for repeated transmissions of the message 3 PUSCH other than the first.

For example, if a PDCCH detected during the contention window duration and the collision resolution identifier included in a transport block included in a PDSCH scheduled by that PDCCH is equal to the value of the collision resolution identifier transmitted in message 3 PUSCH, the media access control layer processing unit 15 may consider collision resolution to have been successfully completed.

For example, if no PDSCH including a collision resolution identifier indicating a value equal to the value of the collision resolution identifier transmitted in message 3 PUSCH is detected during the duration of the contention window, the media access control layer processing unit 15 may determine that collision resolution has not been completed successfully. For example, if the contention window expires, the media access control layer processing unit 15 may determine that collision resolution has not been completed successfully.

For example, if collision resolution is not completed successfully, the media access control layer processing unit 15 may increment the preamble transmission counter.

For example, if collision resolution is not completed successfully, the media access control layer processing unit 15 may increment a request counter. If the request counter reaches a predetermined value #8007, the media access control layer processing unit 15 may recognize that the four-step random access procedure involving a request to apply repeat transmission to message 3 PUSCH has failed. For example, if the media access control layer processing unit 15 recognizes that the four-step random access procedure involving a request to apply repeat transmission to message 3 PUSCH has failed, the media access control layer processing unit 15 may notify upper layers of a random access problem.

Here, the predetermined value #8007 may be determined based on parameters provided by the RRC layer.

Process 8008 is similar to process 5005, so a detailed explanation will be omitted.

After performing process 8008, the media access control layer processing unit 15 may perform process 8009. Here, process 8009 may include a process for sending message A and a process for receiving message B.

In addition, the message B reception process may be a process in which the media access control layer processing unit 15 monitors the PDCCH for a predetermined period of time. Here, the predetermined period is also referred to as the message B window.

For example, the media access control layer processing unit 15 may start the message B window at the first PDCCH monitoring opportunity after the end of the transmission of the random access preamble.

For example, if message B including a first data unit is received during the duration of the message B window and a random access response including a field indicating the index of the selected random access preamble is received, the media access control layer processing unit 15 may consider that reception of the random access response has been successfully completed. If reception of the random access response has been successfully completed, the media access control layer processing unit 15 may proceed to operation 8004 or operation 8007. Here, the random access response may include information instructing the media access control layer processing unit 15 whether to proceed to operation 8004 or operation 8007. The media access control layer processing unit 15 may select either operation 8004 or operation 8007 based on the information included in the random access response.

Here, the data unit may be in a data format or form recognized by the MAC layer.

For example, if message B including a second data unit different from the first data unit is received during the duration of the message B window, and the collision resolution identifier included in the second data unit is equal to the value of the collision resolution identifier transmitted in the message A PUSCH, the media access control layer processing unit 15 may consider reception of message B to be successfully completed. If reception of message B is successfully completed, the media access control layer processing unit 15 may consider reception of the random access response to be successfully completed. Also, if reception of message B is successfully completed, the media access control layer processing unit 15 may consider the random access procedure to be successfully completed.

If the message B window expires and the reception of the random access response is not completed successfully, the media access control layer processing unit 15 may increment the preamble transmission counter. If the value of the preamble transmission counter reaches a predetermined value #5006, the media access control layer processing unit 15 may change "RA_TYPE" to "4STEP_RA" or "4STEP_RAreq". Also, if the value of the preamble transmission counter reaches a predetermined value #5006, the media access control layer processing unit 15 may proceed to process 8002 or process 8005.

Whether the media access control layer processing unit 15 changes "RA_TYPE" to "4STEP_RA" or "4STEP_RAreq" when the value of the preamble transmission counter reaches a predetermined value #5006 may be determined based on some or all of the following: whether the value of the preamble transmission counter has reached the predetermined value #5006; whether random access preamble group B has been configured for the first PRACH resource group; whether random access preamble group B has already been selected; and the uplink signal strength.

Figure 9 is a diagram showing an example of a procedure for selecting "RA_TYPE" by the media access control layer processing unit 15 according to one aspect of this embodiment. First, the media access control layer processing unit 15 may proceed to decision 9001. In decision 9001, a decision regarding the strength of the downlink signal may be made. Here, the decision regarding the strength of the downlink signal in decision 9001 may be made at least based on comparing the RSRP value of the downlink path loss reference with a predetermined threshold #8001. For example, if the RSRP value of the downlink path loss reference is smaller than the predetermined threshold #8001, the media access control layer processing unit 15 may proceed to decision 9002. Alternatively, if the RSRP value of the downlink path loss reference is greater than the predetermined threshold #8001, the media access control layer processing unit 15 may proceed to process 8002. Alternatively, if the RSRP value of the downlink path loss reference is equal to the predetermined threshold #8001, the media access control layer processing unit 15 may proceed to process 8002 or decision 9002.

In decision 9002, the medium access control layer processing unit 15 may determine whether random access preamble group B is configured for the first PRACH resource group. For example, if random access preamble group B is not configured for the first PRACH resource group, the medium access control layer processing unit 15 may proceed to decision 9003. Also, if random access preamble group B is configured for the first PRACH resource group, the medium access control layer processing unit 15 may proceed to process 8005.

In judgment 9003, the media access control layer processing unit 15 may determine whether a random access preamble group has already been selected. If random access preamble group A has already been selected, the media access control layer processing unit 15 may proceed to processing 8005. Alternatively, if random access preamble group B has already been selected, the media access control layer processing unit 15 may proceed to processing 8002. Alternatively, if a random access preamble group has not yet been selected and the transport block size of the payload of message A does not correspond to the transport block size of the payload of message A for random access preamble group B, the media access control layer processing unit 15 may proceed to processing 8005. Alternatively, if a random access preamble group has not yet been selected and the transport block size of the payload of message A corresponds to the transport block size of the payload of message A for random access preamble group B, the media access control layer processing unit 15 may proceed to processing 8002.

The following describes various aspects of the device according to one aspect of this embodiment.

(1) In order to achieve the above object, aspects of the present invention employ the following means. That is, a first aspect of the present invention is a terminal device comprising a medium access control layer processing unit and a physical layer processing unit, wherein the medium access control layer processing unit determines whether a random access preamble group B is configured for a PRACH resource group used for a random access procedure that requests the application of repeated transmission for message 3 PUSCH, and the medium access control layer processing unit determines whether to request the application of repeated transmission for message 3 based on the determination, and instructs the physical layer processing unit to transmit a PRACH.

The programs running on the base station device 3 and terminal device 1 related to the present invention may be programs that control a CPU (Central Processing Unit) or the like (programs that cause a computer to function) so as to realize the functions of the above-described embodiments related to the present invention. Information handled by these devices is temporarily stored in RAM (Random Access Memory) during processing, and is then stored in various types of ROM such as Flash ROM (Read Only Memory) or HDD (Hard Disk Drive), from which it is read, modified, and written by the CPU as needed.

In addition, parts of the terminal device 1 and base station device 3 in the above-described embodiments may be implemented by a computer. In this case, the program for implementing this control function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed to implement the function.

The "computer system" referred to here is a computer system built into the terminal device 1 or base station device 3, and includes hardware such as the OS and peripheral devices. Also, the "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, CD-ROMs, and storage devices such as hard disks built into the computer system.

Furthermore, "computer-readable recording medium" may include something that dynamically stores a program for a short period of time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, or something that stores a program for a fixed period of time, such as volatile memory within a computer system that serves as a server or client in such cases. Furthermore, the above program may be one that realizes some of the functions described above, or may be one that can realize the functions described above in combination with a program already recorded in the computer system.

Furthermore, the base station device 3 in the above-described embodiment can also be realized as a collection (device group) consisting of multiple devices. Each of the devices constituting the device group may have some or all of the functions or functional blocks of the base station device 3 related to the above-described embodiment. It is sufficient for the device group to have all of the functions or functional blocks of the base station device 3. Furthermore, the terminal device 1 related to the above-described embodiment can also communicate with the base station device as a collection.

Furthermore, the base station device 3 in the above-described embodiments may be an EUTRAN (Evolved Universal Terrestrial Radio Access Network) and/or an NG-RAN (NextGen RAN, NR RAN). Furthermore, the base station device 3 in the above-described embodiments may have some or all of the functions of an upper node for an eNodeB and/or a gNB.

Furthermore, some or all of the terminal device 1 and base station device 3 in the above-described embodiments may be realized as an LSI, which is typically an integrated circuit, or as a chipset. Each functional block of the terminal device 1 and base station device 3 may be individually formed into a chip, or some or all may be integrated into a chip. Furthermore, the integrated circuit method is not limited to LSI, and may be realized using a dedicated circuit or a general-purpose processor. Furthermore, if an integrated circuit technology that can replace LSI emerges due to advances in semiconductor technology, it may also be possible to use an integrated circuit based on that technology.

Furthermore, while the above-described embodiment describes a terminal device as an example of a communications device, the present invention is not limited to this and can also be applied to terminal devices or communications devices such as stationary or non-mobile electronic devices installed indoors or outdoors, such as AV equipment, kitchen equipment, cleaning/washing equipment, air conditioning equipment, office equipment, vending machines, and other household appliances.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment and includes design modifications within the scope of the invention. Furthermore, the present invention is susceptible to various modifications within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included within the technical scope of the present invention. Furthermore, configurations in which elements described in the above embodiments are substituted for elements that achieve similar effects are also included.

1 (1A, 1B, 1C) Terminal device 3 Base station device 9 Wireless communication system 10, 30 Physical layer control unit 10a, 30a Radio transmission unit 10b, 30b Radio reception unit 11, 31 Antenna unit 12, 32 RF unit 13, 33 Baseband unit 14, 34 Upper layer processing unit 15, 35 Media access control layer processing unit 16, 36 Radio resource control layer processing unit 5001, 6001, 6002, 6005, 6007, 7001, 7002, 7005, 8001, 9001, 9002, 9003 Decisions 5002, 5003, 5004, 5005, 5006, 6003, 6004, 6006, 6008, 6009, 7003, 7004, 7006, 7007, 8002, 8003, 8004, 8005, 8006, 8007, 8008, 8009 Processing

Claims (2)

a medium access control layer processing unit;
a physical layer processing unit;
Equipped with
The medium access control layer processing unit configures a first PRACH resource group used for a random access procedure requesting application of repetitive transmission for a PUSCH in a message 3 and a second PRACH resource group used for not requesting application of the repetitive transmission to the PUSCH;
selecting one of the first process and the second process based on comparing the RSRP value of the downlink path loss reference with a predetermined threshold;
In the first process, the second PRACH resource group is selected;
In the second process, a first determination is made as to whether a random access preamble group B is configured for the first PRACH resource group;
selecting either a third process or a fourth process based on the first determination;
In the third process, the first PRACH resource group is selected;
In the fourth process, a second determination is made as to whether the random access preamble group B is selected ;
selecting either the first PRACH resource group or the second PRACH resource group based on the second determination;
determining whether to request to apply the repeated transmission for the message 3 PUSCH based on the selected PRACH resource group;
Instructing the physical layer processing unit to transmit a PRACH;
Terminal device. A communication method used in a terminal device, comprising:
Message 3: Configure a first PRACH resource group to be used for a random access procedure requesting application of repetitive transmission for a PUSCH and a second PRACH resource group to be used for not requesting application of the repetitive transmission to the PUSCH;
selecting one of the first process and the second process based on comparing the RSRP value of the downlink path loss reference with a predetermined threshold;
In the first process, the second PRACH resource group is selected;
In the second process, a first determination is made as to whether a random access preamble group B is configured for the first PRACH resource group;
selecting either a third process or a fourth process based on the first determination;
In the third process, the first PRACH resource group is selected;
In the fourth process, a second determination is made as to whether the random access preamble group B is selected ;
selecting either the first PRACH resource group or the second PRACH resource group based on the second determination;
determining whether to request repeated transmission for the message 3 based on the selected PRACH resource group;
Instructing the transmission of PRACH;
Communication method.