HK1242895B - Otdoa (observed time difference of arrival) positioning enhancement by using heterogeneous reference signals - Google Patents

Description

OTDOA (Observed Time Difference of Arrival) positioning enhancement using heterogeneous reference signals

Citation of Related Applications

This application claims priority to U.S. Provisional Patent Application No. 62/107,627, filed January 26, 2015, and entitled “OTDOA POSITIONING ENHANCEMENT BUUSING HETEROGENEOUS REFERENCE SIGNALS,” which is hereby incorporated by reference in its entirety.

Technical Field

The present disclosure relates to wireless technologies, and more particularly to techniques for improving positioning via OTDOA techniques through enhanced Reference Signal Time Difference (RSTD) measurement techniques.

Background Art

Observed Time Difference of Arrival (OTDOA) is a downlink positioning method in LTE. OTDOA is a multi-lateration positioning method in which the UE (User Equipment) measures the time of arrival (TOA) of signals received from multiple base stations (evolved Node Bs (eNBs)) and calculates the Reference Signal Time Difference (RSTD) that is reported to the network. 3GPP (3rd Generation Partnership Project) defines OTDOA using Positioning Reference Signals (PRS).

When the eNB is located outdoors, indoor UEs experience more path loss than outdoor UEs. Consequently, due to the lower SINR (Signal to Interference and Noise Ratio), the number of detectable cells for indoor UEs may be reduced. Currently, 3GPP RAN (Radio Access Network) WG1 (Working Group 1) for Rel-13 (Release 13 of the 3GPP specification) is studying indoor positioning.

In 3GPP TS (Technical Specification) 36.133, E-UTRAN (Evolved Universal Terrestrial RAN) OTD ARS TTD measurements are described, and the UE physical layer can report RSTD for a reference cell with (PRS SINR) >= -6dB and all neighbor cells with (PRS SINR) >= -13dB. These SINRs are set based on considerations related to outdoor UEs. For indoor UEs, the SINR may be more stringent because the signal needs to penetrate buildings.

Summary of the Invention

According to a first aspect of the present disclosure, there is provided an apparatus configured for use within a user equipment (UE). The apparatus includes: a receiver circuit configured to receive one or more RSs of each of a plurality of different types of RSs from each of a plurality of base stations; a processor configured to: determine, for each of the plurality of base stations, a time of arrival (TOA) of the one or more RSs of each of the plurality of different types of RSs; and, for each of the plurality of base stations, calculate a reference signal time difference (RSTD) based at least in part on the TOA of the one or more RSs of each of the plurality of different types of RSs; and a transmitter circuit configured to transmit the RSTD calculated for each of the plurality of base stations.

According to a second aspect of the present disclosure, a machine-readable medium comprising instructions is provided, which, when executed, causes a user equipment (UE) to: receive a set of positioning reference symbols (PRS) from each of a plurality of base stations; receive a set of one or more sets of additional RSs from each of the plurality of base stations, wherein each of the additional RSs is an RS of a different type from the PRSs; measure, for each of the plurality of base stations, a time of arrival (TOA) of each PRS in a set of PRSs and a TOA of each additional RS in a set of one or more sets of additional RSs; calculate, for each of the plurality of base stations, a reference signal time difference (RSTD) based at least in part on the TOA of each PRS in a set of PRSs and the TOA of each additional RS in a set of one or more sets of additional RSs; and send the RSTD for each of the plurality of base stations.

According to a third aspect of the present disclosure, a device configured to be used in a base station is provided. The device includes: a processor configured to: generate a configuration message that assists in implementing a reference signal time difference (RSTD) calculation based on at least two different types of reference signals (RS); and generate multiple RSs, the multiple RSs including a group of one or more RSs of each type of at least two different types of RSs; a transmitter circuit configured to send the configuration message and the multiple RSs to a user equipment (UE); and a receiver circuit configured to receive a set of RSTD measurement results from the UE, one of the RSTD measurement results being based at least in part on the at least two different types of RSs generated by the processor, wherein the processor is further configured to estimate a position of the UE based at least in part on the set of RSTD measurement results.

According to a fourth aspect of the present disclosure, a method for improving positioning at a user equipment (UE) is provided. The method includes: receiving a set of positioning reference symbols (PRS) from each of a plurality of base stations; receiving a set of one or more additional RSs from each of the plurality of base stations, wherein each RS in the additional RSs is an RS of a different type from the PRSs; measuring, for each of the plurality of base stations, a time of arrival (TOA) of each PRS in the set of PRSs and a TOA of each additional RS in the set of one or more additional RSs; calculating, for each of the plurality of base stations, a reference signal time difference (RSTD) based at least in part on the TOA of each PRS in the set of PRSs and the TOA of each additional RS in the set of one or more additional RSs; and sending the RSTD for each of the plurality of base stations.

According to a fifth aspect of the present disclosure, there is provided an apparatus for improving positioning at a user equipment (UE). The apparatus includes: a device for receiving a set of positioning reference symbols (PRS) from each of a plurality of base stations; a device for receiving a set of one or more additional RSs from each of the plurality of base stations, wherein each RS in the additional RSs is an RS of a different type from the PRSs; a device for measuring, for each of the plurality of base stations, a time of arrival (TOA) of each PRS in the set of PRSs and a TOA of each additional RS in the set of one or more additional RSs; a device for calculating, for each of the plurality of base stations, a reference signal time difference (RSTD) based at least in part on the TOA of each PRS in the set of PRSs and the TOA of each additional RS in the set of one or more additional RSs; and a device for sending the RSTD for each of the plurality of base stations.

According to a sixth aspect of the present disclosure, a method for improving positioning at a base station is provided. The method includes: generating a configuration message that assists in implementing a reference signal time difference (RSTD) calculation based on at least two different types of reference signals (RSs); generating multiple RSs, the multiple RSs including a group of one or more RSs of each type of at least two different types of RSs; sending the configuration message and the multiple RSs to a user equipment (UE); receiving a group of RSTD measurement results from the UE, one of the RSTD measurement results being based at least in part on the at least two different types of RSs; and estimating the position of the UE based at least in part on the group of RSTD measurement results.

According to a seventh aspect of the present disclosure, a device for improving positioning at a base station is provided. The device includes: a device for generating a configuration message, the configuration message assisting in implementing a reference signal time difference (RSTD) calculation based on at least two different types of reference signals (RS); a device for generating multiple RSs, the multiple RSs including a group of one or more RSs of each type of at least two different types of RSs; a device for sending the configuration message and the multiple RSs to a user equipment (UE); a device for receiving a group of RSTD measurement results from the UE, one of the RSTD measurement results being based at least in part on at least two different types of RSs; and a device for estimating a position of the UE based at least in part on the group of RSTD measurement results.

According to an eighth aspect of the present disclosure, a machine-readable medium comprising instructions is provided, which, when executed, causes a base station to: generate a configuration message that assists in implementing a reference signal time difference (RSTD) calculation based on at least two different types of reference signals (RS); generate multiple RSs, the multiple RSs comprising a group of one or more RSs of each type of at least two different types of RSs; send the configuration message and the multiple RSs to a user equipment (UE); receive a group of RSTD measurement results from the UE, one of the RSTD measurement results being based at least in part on at least two different types of RSs; and estimate the position of the UE based at least in part on the group of RSTD measurement results.

BRIEF DESCRIPTION OF THE DRAWINGS

1 is a block diagram illustrating an example user equipment (UE) that can be used in conjunction with various aspects described herein.

2 is a block diagram of a system that facilitates RSTD measurement via heterogeneous reference signals (RSs) in accordance with various aspects described herein.

3 is a block diagram of a system that facilitates improved positioning via OTDOA techniques through enhanced reference signal time difference (RSTD) measurement techniques in accordance with various aspects described herein.

4 is a flow chart of a method for facilitating RSTD measurement of a user equipment (UE) via heterogeneous reference signals (RSs) in accordance with various aspects described herein.

5 is a flow chart of a method for facilitating RSTD measurement for one or more UEs based on a set of heterogeneous RSs in accordance with various aspects described herein.

6 is a timing diagram illustrating cell-specific reference signal (CRS) mapping for a normal cyclic prefix (CP), which may be used for enhanced reference signal time difference (RSTD) determination, in accordance with various aspects described herein.

7 is a timing diagram illustrating CRS mapping for an extended CP, which may be used for enhanced RSTD determination, in accordance with various aspects described herein.

FIG8 is a pair of graphs showing the autocorrelation profile (a very important factor for the accuracy of RSTD) for CRS obtained by coherent accumulation within a subframe.

9 is a timing diagram illustrating channel state information reference signal (CSI-RS) mapping for a normal CP, which may be used for enhanced RSTD determination, in accordance with various aspects described herein.

10 is a timing diagram illustrating CSI-RS mapping for an extended CP, which may be used for enhanced RSTD determination, in accordance with various aspects described herein.

11A is a timing diagram illustrating positioning parameter signal (PRS) mapping for a normal CP, which may be used for enhanced RSTD determination, in accordance with various aspects described herein.

11B is a timing diagram illustrating PRS mapping for an extended CP, which may be used for enhanced RSTD determination, in accordance with various aspects described herein.

FIG12 is a pair of graphs showing the autocorrelation profile (a very important factor for the accuracy of RSTD) for PRS obtained by coherent accumulation within a subframe.

13 is a diagram illustrating link layer simulation results comparing the beneficial effects of multiple embodiments according to various aspects described herein.

DETAILED DESCRIPTION

The present disclosure will now be described with reference to the accompanying drawings, wherein similar reference numerals are used to refer to similar elements throughout the accompanying drawings, and the structures and equipment shown therein are not necessarily drawn to scale. As used herein, the terms "component," "system," "interface," etc. are intended to refer to computer-related entities, hardware, software (e.g., in execution) and/or firmware. For example, a component can be a processor (e.g., a microprocessor, a controller or other processing device), the processing, controller, object, executable file, program, storage device, computer, tablet PC, and/or user equipment (e.g., mobile phone, etc.) running on the processor. By way of example, the application and server running on the server can also be a component. One or more components can be located within the processing, and a component can be located on a computer and/or distributed between two or more computers. A group of elements or a group of other components can be described herein, wherein the term "group" can be interpreted as "one or more."

In addition, these components can execute, for example, from various computer-readable storage media having various data structures (e.g., modules) stored thereon. These components can communicate via local and/or remote processes, for example, based on signals having one or more data packets (e.g., data from a component interacting via signals with another component in a local system, in a distributed system, and/or across a network, such as the Internet, a local area network, a wide area network, or similar networks of other systems).

As another example, a component can be a device that has a specific functionality provided by mechanical parts operated by electrical or electronic circuitry, where the electrical or electronic circuitry can be operated by a software application or firmware application executed by one or more processors. The one or more processors can be internal or external to the device and can execute at least a portion of the software or firmware application. As another example, a component can be a device that provides a specific functionality through an electronic component without mechanical parts; the electronic component can include one or more processors to execute the software and/or firmware that at least partially imparts the functionality to the electronic component.

The use of the word "example" is intended to present concepts in a specific way. As used in this application, the word "or" is intended to mean an inclusive "or" rather than an exclusive "or". That is, unless otherwise specified or clear from the context, "X utilizes A or B" is intended to mean any of the naturally included permutations. That is, if X utilizes A; X utilizes B; or X utilizes A and B, then any of these examples satisfies "X utilizes A or B". In addition, the articles "a" and "an" as used in this application and the appended claims should generally be understood to mean "one or more" unless otherwise specified or clear from the context to refer to the singular form. In addition, to the extent that the words "comprises," "has," "with," or variations thereof are used in the specification and claims, these words are intended to be understood as inclusive in a manner similar to the word "comprises."

As used herein, the term "circuit" may refer to, be part of, or include an application-specific integrated circuit (ASIC) that executes one or more software or firmware programs, an electronic circuit, a (shared, dedicated, or clustered) processor and/or (shared, dedicated, or clustered) memory, a combinational logic circuit, and/or other suitable hardware components that provide the described functionality. In some embodiments, the circuit may be implemented in one or more software or firmware modules, or the functionality associated with the circuit may be implemented by one or more software or firmware modules. In some embodiments, the circuit may include logic that is at least partially operable in hardware.

The embodiments described herein can be implemented into a system using any appropriately configured hardware and/or software. FIG1 illustrates example components of a user equipment (UE) device 100 for one embodiment. In some embodiments, the UE device 100 may include application circuitry 102, baseband circuitry 104, radio frequency (RF) circuitry 106, front-end module (FEM) circuitry 108, and one or more antennas 110, coupled together at least as shown.

The application circuitry 102 may include one or more application processors. For example, the application circuitry 102 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The processor(s) may include any combination of general-purpose processors and specialized processors (e.g., graphics processors, application processors, etc.). The processor(s) may be coupled to and/or include a memory/storage device and may be configured to execute instructions stored in the memory/storage device to enable various applications and/or operating systems to run on the system.

The baseband circuitry 104 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The baseband circuitry 104 may include one or more baseband processors and/or control logic to process baseband signals received from the receive signal path of the RF circuitry 106 and generate baseband signals for the transmit signal path of the RF circuitry 106. The baseband processing circuitry 104 may interface with the application circuitry 102 to generate and process baseband signals and control the operation of the RF circuitry 106. For example, in some embodiments, the baseband circuitry 104 may include a second generation (2G) baseband processor 104a, a third generation (3G) baseband processor 104b, a fourth generation (4G) baseband processor 104c, and/or other baseband processors 104d for other existing, developing, or future generations (e.g., fifth generation (5G), 6G, etc.). The baseband circuitry 104 (e.g., one or more of the baseband processors 104a-d) may handle various radio control functions that enable communication with one or more radio networks via the RF circuitry 106. Radio control functions may include, but are not limited to, signal modulation/demodulation, encoding/decoding, radio frequency offset, etc. In some embodiments, the modulation/demodulation circuitry of baseband circuitry 104 may include fast Fourier transform (FFT), precoding, and/or constellation mapping/demapping functions. In some embodiments, the encoding/decoding circuitry of baseband circuitry 104 may include convolution, tail-biting convolution, turbo, Viterbi, and/or low-density parity check (LDPC) encoder/decoder functions. The embodiments of the modulation/demodulation and encoder/decoder functions are not limited to these examples and may include other suitable functions in other embodiments.

In some embodiments, the baseband circuitry 104 may include elements of a protocol stack, such as elements of the Evolved Universal Terrestrial Radio Access Network (EUTRAN) protocol, including, for example, physical (PHY), medium access control (MAC), radio link control (RLC), packet data convergence protocol (PDCP), and/or radio resource control (RRC) elements. The central processing unit (CPU) 104e of the baseband circuitry 104 may be configured to run elements of the protocol stack to implement signaling at the PHY, MAC, RLC, PDCP, and/or RRC layers. In some embodiments, the baseband circuitry may include one or more audio digital signal processors (DSPs) 104f. In other embodiments, the audio DSPs 104f may include elements for compression/decompression and echo cancellation and may include other suitable processing elements. In some embodiments, the components of the baseband circuitry may be appropriately combined in a single chip, a single chipset, or provided on the same circuit board. In some embodiments, some or all of the components of the baseband circuitry 104 and the application circuitry 102 may be implemented together, for example, on a system on a chip (SOC).

In some embodiments, the baseband circuitry 104 can provide communications compatible with one or more radio technologies. For example, in some embodiments, the baseband circuitry 104 can support communications with the Evolved Universal Terrestrial Radio Access Network (EUTRAN) and/or other Wireless Metropolitan Area Networks (WMANs), Wireless Local Area Networks (WLANs), and Wireless Personal Area Networks (WPANs). Embodiments in which the baseband circuitry 104 is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuitry.

RF circuitry 106 can enable communication with a wireless network using modulated electromagnetic radiation through a non-solid medium. In various embodiments, RF circuitry 106 can include switches, filters, amplifiers, etc. to facilitate communication with the wireless network. RF circuitry 106 can include a receive signal path, which can include circuitry for down-converting RF signals received from FEM circuitry 108 and providing a baseband signal to baseband circuitry 104. RF circuitry 106 can also include a transmit signal path, which can include circuitry for up-converting baseband signals provided by baseband circuitry 104 and providing an RF output signal to FEM circuitry 108 for transmission.

In some embodiments, RF circuitry 106 may include a receive signal path and a transmit signal path. The receive signal path of RF circuitry 106 may include mixer circuitry 106a, amplifier circuitry 106b, and filter circuitry 106c. The transmit signal path of RF circuitry 106 may include filter circuitry 106c and mixer circuitry 106a. RF circuitry 106 may also include synthesizer circuitry 106d for synthesizing frequencies for use by mixer circuitry 106a in the receive and transmit signal paths. In some embodiments, mixer circuitry 106a in the receive signal path may be configured to downconvert the RF signal received from FEM circuitry 108 based on the synthesized frequency provided by synthesizer circuitry 106d. Amplifier circuitry 106b may be configured to amplify the downconverted signal, and filter circuitry 106c may be a low-pass filter (LPF) or a band-pass filter (BPF) configured to remove unwanted signals from the downconverted signal to generate an output baseband signal. The output baseband signal may be provided to baseband circuitry 104 for further processing. In some embodiments, the output baseband signal may be a zero-frequency baseband signal, but this is not required.In some embodiments, the mixer circuit 106a of the receive signal path may include a passive mixer, but the scope of the embodiments is not limited in this regard.

In some embodiments, mixer circuit 106a of the transmit signal path may be configured to upconvert an input baseband signal based on a synthesized frequency provided by synthesizer circuit 106d to generate an RF output signal for FEM circuit 108. The baseband signal may be provided by baseband circuit 104 and may be filtered by filter circuit 106c. Filter circuit 106c may include a low-pass filter (LPF), but the scope of the embodiments is not limited in this respect.

In some embodiments, the mixer circuit 106a of the receive signal path and the mixer circuit 106a of the transmit signal path may include two or more mixers and may be arranged to perform quadrature down-conversion and/or up-conversion, respectively. In some embodiments, the mixer circuit 106a of the receive signal path and the mixer circuit 106a of the transmit signal path may include two or more mixers and may be arranged to perform image rejection (e.g., Hartley image rejection). In some embodiments, the mixer circuit 106a of the receive signal path and the mixer circuit 106a of the transmit signal path may be arranged to perform direct down-conversion and/or direct up-conversion, respectively. In some embodiments, the mixer circuit 106a of the receive signal path and the mixer circuit 106a of the transmit signal path may be configured to perform superheterodyne operation.

In some embodiments, the output baseband signal and the input baseband signal may be analog baseband signals, but the scope of the embodiments is not limited in this respect. In some alternative embodiments, the output baseband signal and the input baseband signal may be digital baseband signals. In these alternative embodiments, the RF circuit 106 may include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuits, and the baseband circuit 104 may include a digital baseband interface to communicate with the RF circuit 106.

In some dual-mode embodiments, separate radio IC circuitry may be provided for processing signals for each spectrum, although the scope of the embodiments is not limited in this regard.

In some embodiments, synthesizer circuit 106 d may be a fractional-N synthesizer or a fractional-N/N+1 synthesizer, but the scope of the embodiments is not limited in this respect, as other types of frequency synthesizers may also be suitable. For example, synthesizer circuit 106 d may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer including a phase-locked loop with a frequency divider.

Synthesizer circuit 106d may be configured to synthesize an output frequency based on the frequency input and the divider control input for use by mixer circuit 106a of RF circuit 106. In some embodiments, synthesizer circuit 106d may be a fractional-N/N+1 synthesizer.

In some embodiments, the frequency input may be provided by a voltage-controlled oscillator (VCO), but this is not required. Depending on the desired output frequency, the divider control input may be provided by baseband circuitry 104 or application processor 102. In some embodiments, the divider control input (e.g., N) may be determined from a lookup table based on the channel indicated by application processor 102.

The synthesizer circuit 106d of the RF circuit 106 may include a frequency divider, a delay-locked loop (DLL), a multiplexer, and a phase accumulator. In some embodiments, the frequency divider may be a dual-modulus divider (DMD) and the phase accumulator may be a digital phase accumulator (DPA). In some embodiments, the DMD may be configured to divide the input signal by N or N+1 (e.g., based on a one-shot execution) to provide a fractional division ratio. In some example embodiments, the DLL may include a set of cascaded tunable delay elements, a phase detector, a charge pump, and a D-type flip-flop. In these embodiments, the delay elements may be configured to divide the VCO cycle into Nd equal phase packets, where Nd is the number of delay elements in the delay line. In this way, the DLL provides negative feedback to help ensure that the total delay through the delay line is one VCO cycle.

In some embodiments, the synthesizer circuit 106 d can be configured to generate a carrier frequency as an output frequency, but in other embodiments, the output frequency can be a multiple of the carrier frequency (e.g., twice the carrier frequency, four times the carrier frequency) and combined with a quadrature generator and divider circuit to generate multiple signals at the carrier frequency with multiple different phases relative to each other. In some embodiments, the output frequency can be an LO frequency (f _LO ). In some embodiments, the RF circuit 106 can include an IQ/polarity converter.

FEM circuitry 108 may include a receive signal path that may include circuitry that operates on RF signals received from one or more antennas 110, amplifies the received signals, and provides the amplified versions of the received signals to RF circuitry 106 for further processing. FEM circuitry 108 may also include a transmit signal path that may include circuitry configured to amplify transmit signals provided by RF circuitry 106 for transmission by one or more of one or more antennas 110.

In some embodiments, the FEM circuitry 108 may include a TX/RX switch to switch between transmit and receive modes of operation. The FEM circuitry may include a receive signal path and a transmit signal path. The receive signal path of the FEM circuitry may include a low noise amplifier (LNA) to amplify a received RF signal and provide the amplified received RF signal as an output (e.g., to the RF circuitry 106). The transmit signal path of the FEM circuitry 108 may include a power amplifier (PA) to amplify an input RF signal (e.g., provided by the RF circuitry 106), and one or more filters to generate an RF signal for subsequent transmission (e.g., by one or more of the one or more antennas 110).

In some embodiments, the UE device 100 may include additional elements, such as memory/storage, a display, a camera, sensors, and/or input/output (I/O) interfaces.

In various aspects, heterogeneous signals can be used for RSTD measurements for OTDOA. Accordingly, by increasing the energy, the overall location accuracy can also be improved. In various embodiments, the following example combinations can provide better RSTD measurement performance: (1) a combination of PRS (positioning reference signal) and CRS (cell-specific reference signal); (2) a combination of PRS and CSI-RS (channel state information reference signal); or (3) a combination of PRS, CRS, and CSI-RS.

In the receiving UE, the correlation outputs from multiple signals can be coherently or non-coherently combined. Alternatively, independent RSTD measurements performed by different signals can be combined to obtain a weighted average channel estimate (or correlation output) to obtain RSTD (e.g., w0*CH_CRS+w1*CH_PRS). In order to assist in achieving coherent combination between heterogeneous signals, heterogeneous reference signals can be defined as common antenna ports. In addition, heterogeneous reference signals can be quasi-collocated for coherent and non-coherent combinations (e.g., at least for non-coherent combinations) to prevent the occurrence of scattered RSTD measurement results from different signals. More details about common antenna ports and quasi-collocated (QCL) are discussed below.

In order to obtain accurate measurements from multiple eNBs, time and frequency reuse of low-interference subframes can be utilized as much as possible. However, given a time-frequency reuse factor (3 for CRS and 6 for PRS), additional CRS-IC (interference cancellation), PRS-IC, CSI-IC, or a combination thereof can be used to obtain estimates from as many sources as possible and improve RSTD measurement accuracy. Intelligent interference cancellation technology can measure reference signal received power (RSRP) or quality (RSRQ) from multiple sources and can apply iterative compensation and/or cancellation in cases where conflicting CRS, PRS, CSI-RS patterns are used.

Various embodiments described herein may provide enhanced RSTD measurements based on heterogeneous reference signals, which may help improve positioning over traditional OTDOA positioning techniques.

2, a block diagram of a system 200 for assisting in RSTD measurements via heterogeneous reference signals (RS) according to various aspects described herein is shown. The system 200 may include a receiver circuit 210, a processor 220, a transmitter circuit 230, and a memory 240 (the memory may include any memory in various storage media and may store instructions and/or data associated with one or more of the receiver circuit 210, the processor 220, or the transmitter circuit 230). In various aspects, the system 200 may be included in a user equipment (UE). As will be described in more detail below, the system 200 may assist in achieving improved OTDOA positioning of the UE by RSTD measurements based on heterogeneous RSs.

The receiver circuit 210 may receive a set of RSs from each of a plurality of evolved Node Bs (eNBs), the set of RSs including two or more different types of RSs, such as PRS, CRS, CSI-RS, etc. Based on the location of the UE and the one or more eNBs, these RSs may generally be received at different times.

Optionally, in various aspects, the receiver circuit 210 may receive one or more configuration messages via higher layer signaling (e.g., RRC (Radio Resource Control) and/or LPP (LTE (Long Term Evolution) Positioning Protocol), etc.) that may assist in implementing RSTD measurements of the system 200.

As a first example, a configuration message may specify a common antenna port (AP) associated with two or more completely different types of RS from one or more eNBs. In some such aspects, a common AP (e.g., based on a common precoding vector, etc.) may be associated with two or more completely different types of RS from one or more eNBs until a new configuration message indicates otherwise. In other such aspects, a common AP may be associated with two or more completely different types of RS from one or more eNBs only during a specific designated time period (e.g., a subframe, etc.). Using a common AP for completely different types of RS may facilitate coherent combining as discussed herein.

As a second example, the configuration message may specify one or more APs associated with different RSs from the eNB and indicate that those APs are quasi-collocated (QCLed) to indicate that one or more large-scale properties (e.g., one or more of delay spread, Doppler spread, Doppler shift, average gain, or average delay) of the channel over which a symbol on one of those APs is transmitted can be inferred from the channel over which a symbol on one of the other APs is transmitted.

The processor 220 may determine the time of arrival (TOA) of each RS received from each eNB. Based on the TOA calculated from the RS received from the eNB, the processor 220 may calculate a received signal time difference (RSTD) associated with the eNB. The RSTD for the eNB may be calculated in various ways, which may depend on the specific embodiment and/or the characteristics of the RS received from the eNB (and in embodiments utilizing certain types of interference cancellation (e.g., interference mitigation), the characteristics of the RS received from one or more other eNBs).

As a first example embodiment, the processor 220 may process each of the different types of RS separately and may calculate an RS-specific RSTD associated with the type of RS (e.g., one or more of PRS-RSTD, CRS-RSTD, CSI-RS-RSTD, etc.). Two or more RS-specific RSTDs for an eNB may be combined in various ways to calculate the RSTD for the eNB, such as based on a weighted average. In various aspects, different RS-specific RSTDs may be assigned the same or different weights, where the different weights may be based on various factors, such as the type of RS (e.g., PRS may receive a higher weight), the signal quality associated with the received RS, etc.

As a second example embodiment, processor 220 may combine different types of RSs. For example, if different types of RSs are associated with a common AP (e.g., the common AP is configured via higher-layer signaling), then those different types of RSs may be combined using coherent or non-coherent accumulation. As another example, RSs may be combined based on information that the APs transmitting those RSs are quasi-colocated (e.g., information that may be configured via higher-layer signaling).

The transmitter circuit 230 may transmit the RSTD calculated for each eNB to a master eNB among the multiple eNBs.

3 , a block diagram of a system 300 according to various aspects described herein is shown, which assists in achieving improved positioning via OTDOA technology through enhanced reference signal time difference (RSTD) measurement technology. The system 300 may include a processor 310, a transmitter circuit 320, an optional receiver circuit 330, and a memory 340 (which may include any of a variety of storage media and may store instructions and/or data associated with one or more of the processor 310, the transmitter circuit 320, or the receiver circuit 330). In various aspects, the system 300 may be included in an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) Node B (evolved Node B, eNodeB, or eNB) or other base stations in a wireless communication network. As will be described in more detail below, the system 300 may assist in achieving improved OTDOA positioning technology through heterogeneous reference signals.

In accordance with one or more aspects discussed herein, the processor 310 may optionally generate a configuration message that may configure the UE to perform enhanced RSTD measurements. For example, the configuration message may configure a common AP for one or more different types of RS (e.g., until reconfigured, or specifying a particular subframe, or according to a predetermined or specified subframe pattern, etc.). Alternatively or additionally, the configuration message may configure the UE with information that the APs associated with two or more different types of RS are quasi-colocated. In the same or other aspects, a message that traditionally includes only a CP length for a PRS may also be generated by the processor 310 to additionally include a CP length for one or more different types of RS.

Furthermore, the processor 310 may generate a plurality of RSs that may include two or more different types of RSs that may be used by a UE to determine an RSTD associated with an eNB utilizing the system 300 .

The transmitter circuit 320 may transmit multiple RSs to the UE, and when the processor 310 generates one or more configuration messages, the transmitter circuit 320 may transmit the one or more configuration messages to the UE via higher layer signaling (eg, RRC and/or LPP, etc.).

The receiver circuit 330 may receive a set of RSTD measurement results from the UE, wherein one of the RSTD measurement results is based at least in part on two or more different types of RS generated by the processor 310 .

Based on the received RSTDs and the known locations of the eNBs associated with the respective RSTDs, the processor 310 can estimate the location of the UE. Because the various techniques discussed herein can be used to more accurately determine the RSTDs, the resulting location estimate will also be more accurate than the location estimate obtained by conventional techniques.

4, a flow chart of a method 400 is shown, according to various aspects described herein, for assisting RSTD measurements of a user equipment (UE) via heterogeneous reference signals (RS). In some aspects, the method 400 may be performed at the UE. In other aspects, a machine-readable medium may store instructions associated with the method 400 that, when executed, may cause the UE to perform the steps of the method 400.

At 410, the UE may be optionally configured in one or more of the manners discussed herein for performing enhanced RSTD measurements, such as via a configuration message indicating (either generally or for a specified subframe) a common AP for one or more different types of RS, indicating QCLs of two or more APs associated with different types of RS, indicating additional information to assist in implementing RSTD determination based on multiple different types of RS (e.g., not only the CP length of the PRS, but also the CP length of the CRS and/or CSI-RS, etc.), and the like.

At 420, a set of PRSs may be received from each of a plurality of eNBs.

At 430, additional one or more sets of RS (eg, CRS, CSI-RS, etc.) may be received from each of the plurality of eNBs.

At 440, for each eNB, TOA may be measured for each of the PRSs received from the eNB, and TOA may be measured for each RS in the set of additional different RSs from the eNB.

At 450, based on the TOA measured for the PRS and one or more additional RSs, the RSTD for each eNB can be determined. Depending on the specific embodiment and scenario, one or more different techniques can be applied to determine the RSTD for a given eNB. For example, in some cases (such as when a public AP is configured), a coherent or incoherent combination of PRS with different types of RSs can be utilized. In some cases, for example, if a public AP is utilized and specific RSs from two or more eNBs collide while other RSs do not collide, interference cancellation can be utilized to assist in determining the RSTD. As another example, whether a public AP is utilized or assuming that different APs are QCL, a weighted average of multiple RS-specific RSTDs can be determined, which can provide an improved estimate compared to the RSTD generated based on only one RS.

At 460 , the determined RSTD may be sent to an eNB of a primary cell associated with the eNB utilizing method 400 .

5 , a flow chart of a method 500 is shown for facilitating RSTD measurements for one or more UEs based on a set of heterogeneous RSs, in accordance with various aspects described herein. In some aspects, the method 500 may be performed at an eNB. In other aspects, a machine-readable medium may store instructions associated with the method 500 that, when executed, may cause the eNB to perform the steps of the method 500.

At 510 , the UE may optionally be configured to utilize one or more techniques for enhanced RSTD determination in accordance with various aspects discussed herein.

At 520, two or more different types of RS (eg, PRS, CRS, CSI-RS, etc.) may be generated that may be used by the UE for RSTD determination.

At 530, two or more different types of RS may be sent to the UE.

At 540, a set of RSTD measurements may be received from the UE, each RSTD measurement in the set of RSTD measurements being associated with a different eNB, and a first RSTD in the set of RSTDs being associated with the eNB utilizing method 500. By utilizing one or more enhanced RSTD determination techniques discussed herein, at least the first RSTD may be based on two or more different types of RS.

At 550, the location of the UE can be determined based on the set of RSTD measurements and the known locations of eNBs associated with the RSTD measurements.

6 and 7 , CRS (cell-specific reference signal) mapping for normal CP (cyclic prefix) is shown in FIG6 , and CRS mapping for extended CP is shown in FIG7 . In various embodiments, CRS may be combined with one or more other RSs for OTDOA.

Referring to FIG8 , an autocorrelation profile for the CRS (a very important factor for RSTD accuracy) obtained by coherent accumulation within a subframe is shown at 800, as well as an expanded view of the area within the dashed oval at 810. As shown in the autocorrelation profile of FIG8 , due to the alternating mapping at every third subcarrier in the frequency domain (as can be seen in FIG6 and FIG7 ), the CRS has a fuzzy peak, resulting in three repetitive waveforms in the time domain. The strongest fuzzy peak occurs at -3 dB relative to the target peak.

To reduce fuzzy peaks, one or more of smoothing, interpolation, or filtering may be used in the frequency domain so that an interpolated channel may be estimated for each RE (resource element) and an IFFT (Inverse Fast Fourier Transform) may be employed to estimate the time of the first path of the channel impulse response or the actual peak.

9 and 10, CSI-RS (Channel State Information Reference Signal) mapping for a normal CP (Cyclic Prefix) is shown in FIG9, and CSI-RS mapping for an extended CP is shown in FIG10. In various embodiments, CSI-RS may be combined with one or more other RSs for OTDOA.

Referring to FIG12, the autocorrelation profile for PRS (a very important factor for RSTD accuracy) obtained by coherent accumulation within a subframe is shown at 1200, as well as an expanded view of the area within the dashed oval at 1210. As shown in FIG11A and FIG11B, PRS occupies as many REs as possible, excluding OFDM (Orthogonal Frequency Division Multiplexing) symbols that may contain CRSs, providing a better autocorrelation profile. For example, as shown in FIG12, the strongest fuzzy peak appears near -13 dB relative to the target peak.

In LTE (Long Term Evolution), antenna ports are configured so that the channel on which a symbol on the antenna port is transmitted can be inferred from the channel on which another symbol on the same antenna port is transmitted. For each of the various types of reference signals, such as MBSFN (Multimedia Broadcast Multicast Service Single Frequency Network) reference signals, positioning reference signals, UE-specific reference signals associated with PDSCH (Physical Downlink Shared Channel), and demodulation reference signals associated with EPDCCH (Enhanced Physical Downlink Control Channel), the following provides constraints on the channel of one symbol that can be inferred from the channel of another symbol on the same antenna port. There is one resource grid per antenna port. The set of antenna ports supported depends on the reference signal configuration in the cell, and the reference signal can be any of the following types of reference signals: cell-specific reference signals, MBSFN reference signals, UE-specific reference signals, demodulation reference signals, positioning reference signals, CSI reference signals, etc.

The cell-specific reference signal supports configurations with one, two, or four antenna ports and is transmitted on antenna ports p=0, p∈{0,1}, and p∈{0,1,2,3}, respectively.

The MBSFN reference signal is transmitted on antenna port p = 4. When the two symbols correspond to subframes of the same MBSFN area, the channel on which the symbol on antenna port p = 4 is transmitted can be inferred from the channel on which the other symbol on the same antenna port is transmitted.

The UE-specific reference signal associated with the PDSCH is transmitted on one or more of antenna ports p = 5, p = 7, p = 8, or p ∈ {7, 8, 9, 10, 11, 12, 13, 14}. When two symbols are in the same subframe and in the same PRG (precoding resource block cluster) (when PRB (physical resource block) bundling is used) or in the same PRB pair (when PRB bundling is not used), the channel on which the symbol on one of these antenna ports is transmitted can be inferred from the channel on which the other symbol on the same antenna port is transmitted.

The demodulation reference signal associated with the EPDCCH is sent on one or several antenna ports among p∈{107,108,109,110}. When two symbols are in the same PRB pair, the channel on which the symbol on one of these antenna ports is transmitted can be inferred from the channel on which the other symbol on the same antenna port is transmitted.

A positioning reference signal is sent on antenna port p = 6. The channel on which the symbol on antenna port p = 6 is transmitted can be inferred from the channel on which another symbol on the same antenna port is transmitted within one positioning reference signal occasion consisting of N _PRS consecutive downlink subframes, where N _PRS is configured by higher layers.

The CSI reference signal supports configurations with one, two, four, or eight antenna ports and is transmitted on antenna ports p=15; p=15, 16; p=15, ..., 18; and p=15, ..., 22, respectively.

Two antenna ports are referred to herein as quasi-collocated (QCL) when one or more large-scale properties of the channel over which symbols on one antenna port are transmitted can be inferred from the channel over which symbols on the other antenna port are transmitted. The large-scale properties include one or more of delay spread, Doppler spread, Doppler shift, average gain, or average delay.

Thus, coherent combining between different antenna ports is not possible. Furthermore, in case of different QCL assumptions between different antenna ports, combining reference signals (either coherently or non-coherently) may degrade the RSTD measurement performance.

In a first set of embodiments, heterogeneous reference signals may be combined in one or more ways for RSTD measurement. Thus, in various aspects, more than one RS may be used when a UE measures RSTD. Example combinations include PRS+CRS, PRS+CSI-RS, or PRS+CRS+CSI-RS.

In a second set of embodiments, a common antenna port (AP) may be employed for heterogeneous reference signals, which may facilitate coherent accumulation at the receiving UE. In various aspects, the UE may be configured to assume the use of a common AP for heterogeneous reference signals via higher layer signaling (e.g., RRC (Radio Resource Control) or LPP (LTE (Long Term Evolution) Positioning Protocol) signaling, etc.).

In a third set of embodiments, a receiving UE may assume that antenna ports for heterogeneous reference signals are quasi-collocated. In various aspects, the UE may be configured via higher layer signaling (e.g., RRC or LPP signaling) to assume that antenna ports for heterogeneous reference signals are quasi-collocated.

With reference to Figure 13, a diagram of link layer simulation results comparing the beneficial effects of multiple embodiments according to various aspects discussed herein is shown. The simulation was performed assuming an AWGN (Additive White Gaussian Noise) environment. Assuming a system bandwidth of 10 MHz and RSTD measurements in a single subframe. When the measured RSTD is within ±5T (e.g., as defined in 3GPP TS 36.133), the measurement is considered successful; otherwise, it is considered an erroneous measurement. For the results shown for PRS+CRS using coherent accumulation and incoherent accumulation, it is assumed that the APs for different types of RS are quasi-colocated in accordance with the third group of embodiments discussed above.

As shown in Figure 13, the simulation results show that: the SNR of the existing PRS-based RSTD measurement is 3.13dB stronger than the SNR of the existing CRS-based RSTD measurement, the SNR of the PRS+CRS-based RSTD measurement using incoherent accumulation according to the embodiment discussed in this article is 4.36dB stronger than the SNR of the existing CRS-based RSTD measurement and 1.23dB stronger than the SNR of the existing PRS-based RSTD measurement, and the SNR of the PRS+CRS-based RSTD measurement using coherent accumulation according to the embodiment discussed in this article is 5.03dB stronger than the SNR of the existing CRS-based RSTD measurement and 1.90dB stronger than the SNR of the existing PRS-based RSTD measurement.

In a fourth set of embodiments, the CP (cyclic prefix) length for different reference signals can be signaled together with the PRS CP length. According to 3GPP TS 36.355, cpLength is signaled to the reference cell and (one or more) neighboring cells. However, as shown below, if PRS information is configured, there is no CP information for other RSs. Therefore, other CP-related information for other RSs (e.g., CRS and/or CSI-RS, etc.) (e.g., CP information itself or implicit information about the CP for other RSs, e.g., the CP for other RSs is the same as the CP for PRS) can be signaled together with the PRS CP length.

cpLength

If the prsInfo field is present, the cpLength field specifies the cyclic prefix length of the auxiliary data reference cell PRS; otherwise, the cpLength field specifies the cyclic prefix length of the auxiliary data reference cell CRS.

In a fifth set of embodiments, heterogeneous signals may be utilized in a TDM (time division multiplexing) manner as described herein.

Given that the PRS antenna port and the (one or more) CRS antenna port do not necessarily represent the same physical antenna and can utilize different antenna precoding vectors, coherent combining at the receiver may not be appropriate. However, if multiple RSTD measurements are used, spatial diversity can be advantageously exploited and different precoding can be utilized for PRS transmissions at different time instances. For example, at a particular time instance, the PRS precoding can be the same as the precoding used for one of the CRS antenna ports. If the number of CRS antenna ports is greater than 1, the receiving UE can be configured with information about whether the PRS antenna port is consistent with the (one or more) CRS antenna port at a particular subframe, so that coherent combining can be utilized in such cases.

In some aspects, rules can be defined and staggered PRS transmissions from the same ports as those used by CRS (at the subframe level) can be enabled so that the receiver can be informed at which time instances "Y" (e.g., subframe Y, etc.) the PRS port is aligned with the CRS antenna port "X". In addition, there may be time instances where the PRS and CRS ports are different (e.g., using different precoding). In the latter case, instead of coherent combining, non-coherent combining can be utilized, or a combination of RSTD measurements (e.g., as a weighted average, etc.) can be utilized.

In the sixth group of embodiments, RSTD measurement performance can be improved by assuming that both QCL and common CP can be used for heterogeneous RS. When the QCL assumption is applied and the common AP is reused between two or more RSs (such as CRS and PRS, etc.), one (or more) of the RSs can be used for channel estimation, and interference cancellation can also be applied. As an example, if the CRSs from different cells collide, but the PRSs do not conflict, the PRSs (in different aspects, they can also be combined with CRSs, etc.) for a more accurate initial channel estimation in the frequency domain. The channel can then be used for CRS-IC to facilitate estimation of the channel for the adjacent cell that conflicts in terms of CRS.

In addition, in different aspects, one or more embodiments may include more than one group of embodiments discussed herein (for example, the first to sixth groups of embodiments listed above) or aspects of other embodiments described herein (for example, the example embodiments utilize two or more of the following items: heterogeneous RS combinations, common AP assumptions for heterogeneous RSs, QCL assumptions between APs for heterogeneous RSs, etc.).

Examples herein may include subject matter such as methods, apparatuses for performing steps or blocks of methods, at least one machine-readable medium comprising executable instructions, apparatuses or systems for enabling simultaneous communications using multiple communication technologies, and the like according to the described embodiments and examples, wherein the executable instructions, when executed by a machine (e.g., a processor with memory, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), etc.), cause the machine to perform the steps of the method.

Example 1 is an apparatus configured for use within a user equipment (UE), comprising a receiver circuit, a processor, and a transmitter circuit. The receiver circuit is configured to receive one or more RSs of each of a plurality of different types of RSs from each of a plurality of evolved Node Bs (eNBs). The processor is configured to: determine, for each of the plurality of eNBs, a time of arrival (TOA) of the one or more RSs of each of the plurality of different types of RSs; and, for each of the plurality of eNBs, calculate a reference signal time difference (RSTD) based at least in part on the TOA of the one or more RSs of each of the plurality of different types of RSs. The transmitter circuit is configured to transmit the RSTD calculated for each of the plurality of eNBs.

Example 2 includes the subject matter of Example 1, wherein the one or more RSs of each of the plurality of different types of RSs include one or more positioning RSs (PRSs).

Example 3 includes the subject matter of Example 1, wherein the one or more RSs of each of the plurality of different types of RSs include one or more cell-specific RSs (CRSs).

Example 4 includes the subject matter of Example 1, wherein the one or more RSs of each of the plurality of different types of RSs include one or more channel state information RSs (CSI-RSs).

Example 5 includes the subject matter of any of Examples 1-4, including or omitting the optional features, wherein, for at least one eNB of the plurality of eNBs, the processor is further configured to combine one or more RSs of each type of multiple different types of RSs, wherein each RSTD for the at least one eNB is based at least in part on the combined one or more RSs of each type of the multiple different types of RSs.

Example 6 includes the subject matter of any variation of Example 5, wherein the processor is configured to coherently combine one or more RSs of each type of a plurality of different types of RSs.

Example 7 includes the subject matter of any variation of Example 5, wherein the processor is configured to non-coherently combine one or more RSs of each type of a plurality of different types of RSs.

Example 8 includes the subject matter of any of Examples 1-4, including or omitting the optional features, wherein, for at least one eNB among the plurality of eNBs, the processor is further configured to calculate, for each of a plurality of different types of RSs, an RS-specific RSTD based on one or more RSs of such type, wherein the RSTD for at least one eNB among the plurality of eNBs is based on a weighted combination of the RS-specific RSTDs.

Example 9 includes the subject matter of any of Examples 1-4, including or omitting the optional features, wherein the receiver circuit is further configured to receive a configuration message indicating quasi-colocation of one or more RS of each of a plurality of different types of RS received from a first eNB in the plurality of eNBs.

Example 10 includes the subject matter of any of Examples 1-2, including or omitting the optional features, wherein the one or more RSs of each of the plurality of different types of RSs include one or more cell-specific RSs (CRSs).

Example 11 includes the subject matter of any of Examples 1-3, including or omitting the optional features, wherein the one or more RSs of each of the multiple different types of RSs include one or more channel state information RSs (CSI-RSs).

Example 12 includes the subject matter of any of Examples 1-8, including or omitting the optional features, wherein the receiver circuit is further configured to receive a configuration message indicating quasi-colocation of one or more RSs of each of a plurality of different types of RSs received from a first eNB in the plurality of eNBs.

Example 13 includes the subject matter of Example 1, wherein, for at least one eNB of the plurality of eNBs, the processor is further configured to combine one or more RSs of each type of multiple different types of RSs, wherein each RSTD for the at least one eNB is based at least in part on the combined one or more RSs of each type of the multiple different types of RSs.

Example 14 includes the subject matter of Example 1, wherein, for at least one eNB among the plurality of eNBs, the processor is further configured to calculate, for each of a plurality of different types of RSs, an RS-specific RSTD based on one or more RSs of such type, wherein the RSTD for the at least one eNB among the plurality of eNBs is based on a weighted combination of the RS-specific RSTDs.

Example 15 includes the subject matter of Example 1, wherein the receiver circuit is further configured to receive a configuration message indicating quasi-colocation of one or more RSs of each of a plurality of different types of RSs received from a first eNB of the plurality of eNBs.

Example 16 is a non-transitory machine-readable medium comprising instructions that, when executed, cause a user equipment (UE) to: receive a set of positioning reference symbols (PRS) from each of a plurality of evolved Node Bs (eNBs); receive a set of one or more sets of additional RSs from each of the plurality of eNBs, wherein each of the additional RSs is an RS of a different type than the PRSs; measure, for each of the plurality of eNBs, a time of arrival (TOA) of each PRS in the set of PRSs and a TOA of each additional RS in the set of one or more sets of additional RSs; calculate, for each of the plurality of eNBs, a reference signal time difference (RSTD) based at least in part on the TOA of each PRS in the set of PRSs and the TOA of each additional RS in the set of one or more sets of additional RSs; and transmit the RSTD for each of the plurality of eNBs.

Example 17 includes the subject matter of Example 16, wherein the instructions, when executed, further cause the UE to: receive a configuration message indicating a common antenna port associated with a set of PRSs and one or more sets of additional RSs received from a first eNB among a plurality of eNBs, and combine the set of PRSs from the first eNB with the one or more sets of additional RSs from the first eNB, wherein an RSTD for the first eNB is calculated based at least in part on the combined set of PRSs and one or more sets of additional RSs from the first eNB.

Example 18 includes the subject matter of Example 17, wherein the instructions, when executed, cause the UE to coherently combine a set of PRSs from the first eNB with one or more sets of additional RSs from the first eNB.

Example 19 includes the subject matter of Example 18, wherein the instructions, when executed, cause the UE to receive an additional message indicating one or more subframes in which antenna ports associated with a set of PRS received from the first eNB are aligned with one or more antenna ports associated with one or more sets of additional RS received from the first eNB.

Example 20 includes the subject matter of Example 17, wherein the instructions, when executed, cause the UE to non-coherently combine a set of PRSs from the first eNB with one or more sets of additional RSs from the first eNB.

Example 21 includes the subject matter of Example 17, wherein the instructions, when executed, cause the UE to perform interference cancellation between one or more sets of additional RSs received from a first eNB in the plurality of eNBs and one or more sets of additional RSs received from a second eNB in the plurality of eNBs.

Example 22 includes the subject matter of Example 16, wherein the instructions, when executed, further cause the UE to: receive a configuration message indicating quasi-colocation of antenna ports associated with a set of PRSs and one or more antenna ports associated with one or more sets of additional RSs received from a first eNB among the plurality of eNBs, and combine the set of PRSs from the first eNB with the one or more sets of additional RSs from the first eNB, wherein RSTD for the first eNB is calculated based at least in part on the combined set of PRSs and the one or more sets of additional RSs from the first eNB.

Example 23 includes the subject matter of Example 22, wherein the instructions, when executed, cause the UE to non-coherently combine a set of PRSs from the first eNB with one or more sets of additional RSs from the first eNB.

Example 24 includes the subject matter of any of Examples 16-23, including or omitting the optional features, wherein the instructions, when executed, further cause the UE to receive a configuration message indicating a cyclic prefix (CP) length associated with a set of PRSs and one or more CP lengths associated with one or more sets of additional RSs received from a first eNB among the multiple eNBs.

Example 25 includes the subject matter of Example 16, wherein the instructions, when executed, further cause the UE to calculate, for at least a first eNB among the plurality of eNBs, a PRS-RSTD based on a set of PRSs received from the first eNB and one or more additional RS-specific RSTDs based on one or more sets of additional RSs received from the first eNB, wherein the RSTD is calculated based on a weighted combination of the PRS-RSTD and the one or more additional RS-specific RSTDs.

Example 26 includes the subject matter of Example 16, wherein the instructions, when executed, further cause the UE to receive a configuration message indicating a cyclic prefix (CP) length associated with a set of PRSs and one or more CP lengths associated with one or more sets of additional RSs received from a first eNB among the plurality of eNBs.

Example 27 is an apparatus configured for use within an evolved Node B (eNB), comprising a processor, a transmitter circuit, and a receiver circuit. The processor is configured to: generate a configuration message that assists in implementing a reference signal time difference (RSTD) calculation based on at least two different types of reference signals (RS); and generate multiple RSs, the multiple RSs including a group of one or more RSs of each type of at least two different types of RSs. The transmitter circuit is configured to send the configuration message and the multiple RSs to a user equipment (UE). The receiver circuit is configured to receive a set of RSTD measurement results from the UE. The processor is further configured to estimate the position of the UE based at least in part on the set of RSTD measurement results.

Example 28 includes the subject matter of Example 27, wherein the configuration message indicates a common antenna port associated with each of the at least two different types of RS.

Example 29 includes the subject matter of Example 27, wherein the configuration message indicates quasi-colocation of antenna ports associated with each of the at least two different types of RS.

Example 30 includes the subject matter of any of Examples 27-29, including or omitting the optional features, wherein the transmitter circuit is configured to send the configuration message as a radio resource control (RRC) message.

Example 31 includes the subject matter of any of Examples 27-29, including or omitting the optional features, wherein the transmitter circuit is configured to transmit the configuration message as a Long Term Evolution (LTE) Positioning Protocol (LPP) message.

Example 32 includes the subject matter of any of Examples 27-29, including or omitting the optional features, wherein the transmitter circuit is configured to send a cyclic prefix (CP) length associated with each of at least two different types of RS to the UE.

Example 33 includes the subject matter of any of Examples 27-29, including or omitting the optional features, wherein the transmitter circuit is configured to send a cyclic prefix (CP) length associated with each of at least two different types of RS to the UE.

Example 34 includes the subject matter of Example 27, wherein the transmitter circuit is configured to transmit the configuration message as a radio resource control (RRC) message.

Example 35 includes the subject matter of Example 27, wherein the transmitter circuit is configured to transmit the configuration message as a Long Term Evolution (LTE) Positioning Protocol (LPP) message.

Example 36 includes the subject matter of Example 27, wherein the transmitter circuit is configured to transmit, to the UE, a cyclic prefix (CP) length associated with each of the at least two different types of RS.

Example 37 is a device configured for use within a user equipment (UE), comprising a device for receiving, a device for processing, and a device for sending. The device for receiving is configured to receive one or more RSs of each of a plurality of different types of RSs from each of a plurality of evolved Node Bs (eNBs). The device for processing is configured to: determine, for each of the plurality of eNBs, a time of arrival (TOA) of the one or more RSs of each of the plurality of different types of RSs; and calculate, for each of the plurality of eNBs, a reference signal time difference (RSTD) based at least in part on the TOA of the one or more RSs of each of the plurality of different types of RSs. The device for sending is configured to send the RSTD calculated for each of the plurality of eNBs.

Example 38 is a device configured for use within an evolved Node B (eNB), comprising a device for processing, a device for sending, and a device for receiving. The device for processing is configured to: generate a configuration message that assists in implementing a reference signal time difference (RSTD) calculation based on at least two different types of reference signals (RS); and generate multiple RSs, the multiple RSs including a group of one or more RSs of each type of at least two different types of RSs. The device for sending is configured to send a configuration message and multiple RSs to a user equipment (UE). The device for receiving is configured to receive a set of RSTD measurement results from the UE. The device for processing is also configured to estimate the position of the UE based at least in part on a set of RSTD measurement results.

The above description of the illustrated embodiments of the present disclosure (including what is described in the Abstract) is not intended to be exhaustive or to limit the disclosed embodiments to the precise forms disclosed. Although specific embodiments and examples are described herein for illustrative purposes, those skilled in the relevant art will recognize that various modifications are possible that are considered to be within the scope of these embodiments and examples.

In view of this, although the disclosed subject matter is described in conjunction with various applicable embodiments and corresponding drawings, it should be understood that other similar embodiments may be used or modifications and additions may be made to the described embodiments to achieve the same, similar, alternative or replacement functionality without departing from the disclosed subject matter. Therefore, the disclosed subject matter should not be limited to any single embodiment described herein, but should be construed in accordance with the scope of the appended claims.

In particular, with respect to the various functions performed by the above-described components or structures (assemblies, devices, circuits, systems, etc.), the terms used to describe these components (including references to "means") are intended to correspond (unless otherwise indicated) to any component or structure (e.g., a functionally equivalent component) that performs the specified function of the described component, even if the component or structure is not structurally equivalent to the disclosed structure that performs the described function in the exemplary implementations shown herein. In addition, although a particular feature may be disclosed for only one of several implementations, such feature may be combined with one or more other features of other implementations as desired and advantageous for any given or particular application.

Claims (63)

1. An apparatus configured for use within a user equipment (UE), comprising: A receiver circuit configured to receive one or more RSs of each of multiple different types from each of a plurality of base stations; The processor is configured as follows: For each of the plurality of base stations, determine the Time of Arrival (TOA) of one or more RSs of each of the plurality of different types of RSs; and For each of the plurality of base stations, the reference signal time difference (RSTD) is calculated at least in part based on the TOA of one or more RSs of each of the plurality of different types of RSs; and A transmitter circuit configured to transmit an RSTD calculated for each of the plurality of base stations. 2. The apparatus of claim 1, wherein each of the multiple different types of RS comprises one or more positioning RSs (PRS). 3. The apparatus of claim 1, wherein each of the multiple different types of RS comprises one or more cell-specific RSs (CRS). 4. The apparatus of claim 1, wherein each of the multiple different types of RSs comprises one or more Channel State Information RSs (CSI-RS). 5. The apparatus according to any one of claims 1-4, wherein, for at least one of the plurality of base stations, the processor is further configured to combine one or more RSs of each of the plurality of different types of RSs, wherein each RSTD for the at least one base station is based at least in part on one or more RSs of each of the plurality of different types of RSs combined. 6. The apparatus of claim 5, wherein the processor is configured to coherently combine one or more RSs of each of the plurality of different types of RSs. 7. The apparatus of claim 5, wherein the processor is configured to incoherently combine one or more RSs of each of the plurality of different types of RSs. 8. The apparatus according to any one of claims 1-4, wherein, for at least one of the plurality of base stations, the processor is further configured to calculate an RS-specific RSTD based on one or more RSs of each of the plurality of different types of RSs, wherein the RSTD for the at least one of the plurality of base stations is based on a weighted combination of the RS-specific RSTDs. 9. The apparatus according to any one of claims 1-4, wherein the receiver circuitry is further configured to receive a configuration message indicating quasi-co-location of one or more RSs of each of the plurality of different types received from a first base station of the plurality of base stations. 10. A machine-readable medium including instructions that, when executed, cause a user equipment (UE) to: Receive a set of Positioning Reference Symbols (PRS) from each of multiple base stations; Receive one or more additional RSs from each of the plurality of base stations, wherein each of the additional RSs is an RS of a different type from the PRS; For each of the plurality of base stations, the time of arrival (TOA) of each PRS in the set of PRS and the TOA of each additional RS in the set or plurality of additional RS are measured; For each of the plurality of base stations, the reference signal time difference (RSTD) is calculated at least in part based on the time of arrival (TOA) of each PRS in the set of PRS and the TOA of each additional RS in the set or more additional RS; and The RSTD is sent for each of the plurality of base stations. 11. The machine-readable medium of claim 10, wherein the instructions, when executed, further cause the UE to: Receive a configuration message indicating the common antenna port associated with the set of PRS and the set or more additional RS received from the first base station of the plurality of base stations, and The set of PRS from the first base station is combined with the set of one or more additional RS from the first base station. The RSTD for the first base station is calculated at least in part based on a combined set of PRS and one or more additional sets of RS from the first base station. 12. The machine-readable medium of claim 11, wherein the instructions, when executed, cause the UE to coherently combine the set of PRS from the first base station with the set or more additional RS from the first base station. 13. The machine-readable medium of claim 12, wherein the instructions, when executed, cause the UE to receive an additional message indicating one or more subframes, wherein an antenna port associated with the set of PRS received from the first base station is aligned with one or more antenna ports associated with the set or more additional RS received from the first base station. 14. The machine-readable medium of claim 11, wherein the instructions, when executed, cause the UE to incoherently combine the set of PRS from the first base station with the set or more additional RS from the first base station. 15. The machine-readable medium of claim 11, wherein the instructions, when executed, cause the UE to perform interference cancellation between the set of or more additional RS received from a first base station of the plurality of base stations and the set of or more additional RS received from a second base station of the plurality of base stations. 16. The machine-readable medium of claim 10, wherein the instructions, when executed, further cause the UE to: Receive a configuration message indicating quasi-co-location of antenna ports associated with the set of PRS and one or more antenna ports associated with the set or more additional RS received from a first base station among the plurality of base stations, and The set of PRS from the first base station is combined with the set of one or more additional RS from the first base station. The RSTD for the first base station is calculated at least in part based on a combined set of PRS and one or more additional sets of RS from the first base station. 17. The machine-readable medium of claim 16, wherein the instructions, when executed, cause the UE to incoherently combine the set of PRS from the first base station with the set or more additional RS from the first base station. 18. The machine-readable medium according to any one of claims 10-17, wherein the instructions, when executed, further cause the UE to receive a configuration message indicating a cyclic prefix (CP) length associated with the set of PRSs and one or more CP lengths associated with the set or sets of additional RSs received from a first base station of the plurality of base stations. 19. The machine-readable medium of claim 10, wherein the instructions, when executed, further cause the UE to calculate, for at least a first base station among the plurality of base stations, a PRS-RSTD based on the set of PRS received from the first base station and one or more additional RS-specific RSTDs based on the set or more additional RSs received from the first base station, wherein the RSTDs are calculated based on a weighted combination of the PRS-RSTDs and the one or more additional RS-specific RSTDs. 20. An apparatus configured for use within a base station, comprising: The processor is configured as follows: Generate a configuration message that assists in calculating the Reference Signal Time Difference (RSTD) based on at least two different types of reference signals (RS); and Generate multiple RSs, which include one or more RSs of each of the at least two different types of RSs; A transmitter circuit configured to transmit the configuration message and the plurality of RSs to a user equipment (UE); and A receiver circuit configured to receive a set of RSTD measurement results from the UE, wherein one of the RSTD measurement results is based at least in part on the at least two different types of RS generated by the processor. The processor is also configured to estimate the location of the UE based at least in part on the set of RSTD measurements. 21. The apparatus of claim 20, wherein the configuration message indicates a common antenna port associated with each of the at least two different types of RS. 22. The apparatus of claim 20, wherein the configuration message indicates quasi-co-location of the antenna port associated with each of the at least two different types of RS. 23. The apparatus according to any one of claims 20-22, wherein the transmitter circuitry is configured to transmit the configuration message as a Radio Resource Control (RRC) message. 24. The apparatus of any one of claims 20-22, wherein the transmitter circuitry is configured to transmit the configuration message as a Long Term Evolution (LTE) Positioning Protocol (LPP) message. 25. The apparatus of any one of claims 20-22, wherein the transmitter circuitry is further configured to transmit to the UE a cyclic prefix (CP) length associated with each of the at least two different types of RS. 26. A method for improving positioning at a user equipment (UE), comprising: Receive a set of Positioning Reference Symbols (PRS) from each of multiple base stations; Receive one or more additional RSs from each of the plurality of base stations, wherein each of the additional RSs is an RS of a different type from the PRS; For each of the plurality of base stations, the time of arrival (TOA) of each PRS in the set of PRS and the TOA of each additional RS in the set or plurality of additional RS are measured; For each of the plurality of base stations, the reference signal time difference (RSTD) is calculated at least in part based on the time of arrival (TOA) of each PRS in the set of PRS and the TOA of each additional RS in the set or plurality of additional RS; and The RSTD is sent for each of the plurality of base stations. 27. The method of claim 26, further comprising: Receive a configuration message indicating the common antenna port associated with the set of PRS and the set or more additional RS received from the first base station of the plurality of base stations, and The set of PRS from the first base station is combined with the set of one or more additional RS from the first base station. The RSTD for the first base station is calculated at least in part based on a combined set of PRS and one or more additional sets of RS from the first base station. 28. The method of claim 27, wherein combining the set of PRS from the first base station with the set or more additional RS from the first base station comprises coherently combining the set of PRS from the first base station with the set or more additional RS from the first base station. 29. The method of claim 28, further comprising: receiving an additional message indicating one or more subframes, wherein an antenna port associated with the set of PRS received from the first base station is aligned with one or more antenna ports associated with the set or more additional RS received from the first base station. 30. The method of claim 27, wherein combining the set of PRS from the first base station with the set or more additional RS from the first base station comprises incoherently combining the set of PRS from the first base station with the set or more additional RS from the first base station. 31. The method of claim 27, further comprising: performing interference cancellation between the set of or more additional RS received from a first base station of the plurality of base stations and the set of or more additional RS received from a second base station of the plurality of base stations. 32. The method of claim 26, further comprising: Receive a configuration message indicating quasi-co-location of antenna ports associated with the set of PRS and one or more antenna ports associated with the set or more additional RS received from a first base station among the plurality of base stations, and The set of PRS from the first base station is combined with the set of one or more additional RS from the first base station. The RSTD for the first base station is calculated at least in part based on a combined set of PRS and one or more additional sets of RS from the first base station. 33. The method of claim 32, wherein combining the set of PRS from the first base station with the set or more additional RS from the first base station comprises incoherently combining the set of PRS from the first base station with the set or more additional RS from the first base station. 34. The method according to any one of claims 26-33, further comprising receiving a configuration message indicating a cyclic prefix (CP) length associated with the set of PRSs and one or more CP lengths associated with the set or sets of additional RSs received from a first base station of the plurality of base stations. 35. The method of claim 26, further comprising, for at least a first base station of the plurality of base stations, calculating a PRS-RSTD based on the set of PRS received from the first base station and one or more additional RS-specific RSTDs based on the set or more additional RS received from the first base station, wherein the RSTD is calculated based on a weighted combination of the PRS-RSTD and the one or more additional RS-specific RSTDs. 36. An apparatus for improving positioning at a user equipment (UE), comprising: A means for receiving a set of positioning reference symbols (PRS) from each of a plurality of base stations; A means for receiving one or more sets of additional RSs from each of the plurality of base stations, wherein each of the additional RSs is an RS of a different type from the PRS; A means for measuring the time of arrival (TOA) of each PRS in a set of PRSs and the TOA of each additional RS in a set or more sets of additional RSs for each of the plurality of base stations; A means for calculating, at least in part, the reference signal time difference (RSTD) for each of the plurality of base stations based on the time of arrival (TOA) of each PRS in the set of PRSs and the TOA of each additional RS in the set or plurality of additional RSs; and A means for transmitting the RSTD for each of the plurality of base stations. 37. The apparatus of claim 36, further comprising: A means for receiving a configuration message indicating a common antenna port associated with the set of PRS and the set or more additional RS received from a first base station of the plurality of base stations, and A means for combining the set of PRS from the first base station with the set or more additional RS from the first base station. The RSTD for the first base station is calculated at least in part based on a combined set of PRS and one or more additional sets of RS from the first base station. 38. The apparatus of claim 37, wherein the means for combining the set of PRS from the first base station with the set or more additional RS from the first base station includes means for coherently combining the set of PRS from the first base station with the set or more additional RS from the first base station. 39. The apparatus of claim 38, further comprising: means for receiving additional messages indicating one or more subframes, wherein an antenna port associated with the set of PRS received from the first base station is aligned with one or more antenna ports associated with the set or more additional RS received from the first base station. 40. The apparatus of claim 37, wherein the means for combining the set of PRS from the first base station with the set or more additional RS from the first base station includes means for incoherently combining the set of PRS from the first base station with the set or more additional RS from the first base station. 41. The apparatus of claim 37, further comprising: means for performing interference cancellation between the set of or more additional RS received from a first base station of the plurality of base stations and the set of or more additional RS received from a second base station of the plurality of base stations. 42. The device according to claim 36, further comprising: A means for receiving a configuration message indicating quasi-co-location of antenna ports associated with the set of PRS and one or more antenna ports associated with the set or more additional RS received from a first base station of the plurality of base stations, and A means for combining the set of PRS from the first base station with the set or more additional RS from the first base station. The RSTD for the first base station is calculated at least in part based on a combined set of PRS and one or more additional sets of RS from the first base station. 43. The apparatus of claim 42, wherein the means for combining the set of PRS from the first base station with the set or more additional RS from the first base station includes means for incoherently combining the set of PRS from the first base station with the set or more additional RS from the first base station. 44. The apparatus according to any one of claims 36-43, further comprising means for receiving a configuration message indicating a cyclic prefix (CP) length associated with the set of PRSs and one or more CP lengths associated with the set or sets of additional RSs received from a first base station of the plurality of base stations. 45. The apparatus of claim 36, further comprising means for calculating, for at least a first base station among the plurality of base stations, a PRS-RSTD based on the set of PRS received from the first base station and one or more additional RS-specific RSTDs based on the set or more additional RS received from the first base station, wherein the RSTD is calculated based on a weighted combination of the PRS-RSTD and the one or more additional RS-specific RSTDs. 46. A method for improving positioning at a base station, comprising: Generate a configuration message that assists in the calculation of the reference signal time difference (RSTD) based on at least two different types of reference signals (RS); Generate multiple RSs, which include one or more RSs of each of the at least two different types of RSs; Send the configuration message and the plurality of RS to the user equipment (UE); Receives a set of RSTD measurement results from the UE, wherein one of the RSTD measurement results is based at least in part on the at least two different types of RS; and The location of the UE is estimated at least in part based on the set of RSTD measurements. 47. The method of claim 46, wherein the configuration message indicates a common antenna port associated with each of the at least two different types of RS. 48. The method of claim 46, wherein the configuration message indicates quasi-co-location of the antenna port associated with each of the at least two different types of RS. 49. The method according to any one of claims 46-48, wherein sending the configuration message to the UE and the plurality of RSs further comprises sending the configuration message as a Radio Resource Control (RRC) message. 50. The method according to any one of claims 46-48, wherein sending the configuration message to the UE and the plurality of RSs further comprises sending the configuration message as a Long Term Evolution (LTE) Positioning Protocol (LPP) message. 51. The method according to any one of claims 46-48, wherein sending the configuration message and the plurality of RSs to the UE further comprises sending to the UE a cyclic prefix (CP) length associated with each of the at least two different types of RSs. 52. An apparatus for improving positioning at a base station, comprising: A means for generating a configuration message that assists in the calculation of reference signal time difference (RSTD) based on at least two different types of reference signals (RS); A means for generating a plurality of RS, the plurality of RS including a set of one or more RS of each of the at least two different types of RS; A means for sending the configuration message and the plurality of RSs to a user equipment (UE); A means for receiving a set of RSTD measurement results from the UE, wherein one of the RSTD measurement results is based at least in part on the at least two different types of RS; and A means for estimating the location of the UE based at least in part on the set of RSTD measurements. 53. The device of claim 52, wherein the configuration message indicates a common antenna port associated with each of the at least two different types of RS. 54. The device of claim 52, wherein the configuration message indicates quasi-co-location of the antenna port associated with each of the at least two different types of RS. 55. The apparatus according to any one of claims 52-54, wherein the means for sending the configuration message and the plurality of RSs to the UE further comprises means for sending the configuration message as a Radio Resource Control (RRC) message. 56. The apparatus according to any one of claims 52-54, wherein the means for sending the configuration message and the plurality of RSs to the UE further comprises means for sending the configuration message as a Long Term Evolution (LTE) Positioning Protocol (LPP) message. 57. The device according to any one of claims 52-54, wherein the means for sending the configuration message and the plurality of RSs to the UE further comprises means for sending to the UE a cyclic prefix (CP) length associated with each of the at least two different types of RSs. 58. A machine-readable medium including instructions, which, when executed, cause a base station to: Generate a configuration message that assists in the calculation of the reference signal time difference (RSTD) based on at least two different types of reference signals (RS); Generate multiple RSs, which include one or more RSs of each of the at least two different types of RSs; Send the configuration message and the plurality of RS to the user equipment (UE); Receives a set of RSTD measurement results from the UE, wherein one of the RSTD measurement results is based at least in part on the at least two different types of RS; and The location of the UE is estimated at least in part based on the set of RSTD measurements. 59. The machine-readable medium of claim 58, wherein the configuration message indicates a common antenna port associated with each of the at least two different types of RS. 60. The machine-readable medium of claim 58, wherein the configuration message indicates quasi-co-location of the antenna port associated with each of the at least two different types of RS. 61. The machine-readable medium according to any one of claims 58-60, wherein the instructions, when executed, cause the base station to send the configuration message as a radio resource control (RRC) message. 62. The machine-readable medium according to any one of claims 58-60, wherein the instructions, when executed, cause the base station to send the configuration message as a Long Term Evolution (LTE) Positioning Protocol (LPP) message. 63. The machine-readable medium according to any one of claims 58-60, wherein the instructions, when executed, cause the base station to send to the UE a cyclic prefix (CP) length associated with each of the at least two different types of RS.