CN100442876C - A method for realizing shared reverse traffic channel to transmit reverse signaling - Google Patents

Abstract

The invention relates to a method for realizing a shared reverse service channel to transmit reverse signaling in the technical field of communication. The method comprises: the mobile station MS sends the reverse signaling with the user identification through the reverse traffic channel; the base station controller sends the response message with the user identification to the MS after receiving the reverse signaling; the MS receives After receiving the response message, turn off the transmit power on the reverse traffic channel. Utilizing the method of the invention can enable users under the carrier frequency of the same sector to share one or more service channels to transmit reverse signaling, thereby saving system resources and increasing system capacity.

Description

A method for realizing shared reverse traffic channel to transmit reverse signaling

technical field

The invention relates to the technical field of communication, in particular to a method for realizing a shared reverse service channel to transmit reverse signaling.

Background technique

The CDMA system is one of the current mainstream mobile communication systems, and has the advantages of large system capacity, high voice quality, and strong confidentiality. In the CDMA system, there are two types of reverse logical signaling channels: r-csch (reverse common signaling channel) and r-dsch (reverse dedicated signaling channel). Among them, r-csch is usually mapped to R-ACH (reverse access channel); r-dsch is usually mapped to R-FCH (reverse fundamental channel) or R-DCCH (reverse dedicated control channel). Reverse physical channels may be collectively referred to as R-TCH (Reverse Traffic Channel).

The CDMA protocol stipulates that r-csch is used to transmit reverse call signaling when a call is established, and users under the carrier frequency of the same sector can share this channel; while r-dsch is exclusive to the user, and is used by the system after the call is established. Assigned by the user, the user can use it to transmit his own switching, power control and other signaling. In short, r-csch or R-ACH is a common signaling channel; r-dsch or R-TCH is a dedicated signaling channel.

As a dedicated dispatching communication system, the trunking communication system has the characteristics of channel resource sharing, user grouping, multi-level priority control, and large system capacity. The trunking system is also called PTT (Push To Talk) system, and its communication mode is half-duplex, which can be performed between a pair of users, that is, a single call; it can also be performed between users in a group, that is, a group call. When the user needs to speak, press the PTT button to request the right to speak from the system. After authorization, the system will give the user a prompt. At this time, the user can start speaking, and the other party or users in the group can hear the speaker's voice, and the speaker releases the PTT button to stop. Speaking, there can be multiple such PTT interactions during a call. The half-duplex communication feature of PTT enables the trunking system to share the forward and reverse channels, that is, forward a service channel to broadcast voices to users in the group, and a reverse channel to transmit uplink voices for speaking users.

At present, realizing the function of the trunking system on the CDMA system is a research direction concerned in this field. Different from the time-division system, due to the limitations of the CDMA protocol and chip, the CDMA mobile station cannot work on the r-csch at the same time when it is in the traffic channel state, that is, in the call state, so the PTT talk right request signaling must be sent in the business channel, while the CDMA service channel is assigned independently to each user in the call and cannot be shared.

In response to the above problems, OMA (Open Mobile Alliance) has formulated the PoC (cellular network-based PTT) standard, which is suitable for cellular systems with certain data service capabilities. Each user needs to use a pair of dedicated front and back channels to pass data PTT signaling is transmitted in the form of business. However, this method cannot realize channel sharing, and has the defects of slow call establishment speed and high voice delay.

The prior art proposes a PTT scheme, which can only be used in the CDMA 1x system. Each user needs to use a pair of dedicated forward and reverse channels, and PTT signaling is sent on the dedicated channel. This solution also has the defect that channel sharing cannot be realized. At the same time, the performance on CDMA 1x Release 0 is poor, and only on CDMA 1X Release A can it have better performance.

Contents of the invention

The purpose of the present invention is to provide a method for realizing the sharing of reverse traffic channels to transmit reverse signaling, which can enable users under the carrier frequency of the same sector to share one or more traffic channels to transmit reverse signaling, saving system resources , Increase system capacity.

The purpose of the present invention is achieved through the following technical solutions:

A method for implementing a shared reverse traffic channel to transmit reverse signaling, comprising:

A, the mobile station MS selects a reverse traffic channel from the reverse traffic channels that have been established, and sends the reverse signaling with the user identification through the selected reverse traffic channel;

B. Receive a response message with the user identifier sent by the base station controller.

Before the MS sends the reverse signaling with the user identifier, the method further includes:

The MS sends the preamble to enable the base transceiver station to capture the MS;

The base transceiver station forwards the preamble to the base station controller.

Described step A further comprises:

After receiving the preamble, the base station controller sends a response message to the MS, and the MS sends the reverse signaling with the user identification after receiving the response message.

The method further comprises:

After sending the reverse signaling, the MS turns off the transmit power on the reverse traffic channel after receiving the response message; or,

If the MS does not receive a response message after sending reverse signaling for many times, it will be terminated automatically.

The transmission power of the MS for sending reverse signaling is obtained through open-loop power control, the initial power is estimated in open-loop according to the strength of the forward signal, and the subsequent retransmission increases by a predetermined power step value each time.

It can be seen from the above technical solution provided by the present invention that the present invention realizes that the CDMA trunking system can share the reverse signaling channel, thereby saving system resources and increasing system capacity.

Description of drawings

Fig. 1 is an operation flowchart of an embodiment of the method of the present invention.

Detailed ways

The core idea of the present invention is to provide a method for realizing the shared reverse traffic channel to transmit reverse signaling, which can enable users under the carrier frequency of the same sector to share one or more traffic channels to transmit reverse signaling, thereby saving System resources, increase system capacity.

The present invention provides a method for realizing the shared reverse traffic channel to transmit reverse signaling. The method can be applied to CDMA2000, WCDMA or TD-SCDMA. This embodiment takes the method applied to CDMA2000 as an example for illustration. Any kind of R-TCH, including: R-FCH (reverse fundamental channel), R-DCCH (reverse dedicated control channel), R-SCH (direction supplementary channel), etc., these reverse business Channels are collectively referred to as R-TCHs; F-TCH (Forward Traffic Channel) can be any physical channel, including: F-FCH (Forward Fundamental Channel), F-DCCH (Forward Dedicated Control Channel), F-SCH (forward supplementary channel) etc.; a kind of embodiment operation process of method of the present invention is as shown in Figure 1, specifically comprises the following steps:

Step 1: The MS sends the preamble to the system on the reverse pilot channel R-PICH to make the BTS capture the MS;

The BTS detects the transmission of the MS and can start to demodulate its transmitted signal;

Step 2: After the BTS captures the Preamble transmitted by the MS, it forwards it to the BSC through the reverse service frame Abis-IS2000TCH Reverse;

Step 3: After receiving the Preamble, the BSC sends a response to the BTS through the forward service frame Abis-IS2000 TCHForward;

Step 4: After receiving the response, the BTS sends a response message BS AckOrder to the MS through the F-TCH;

Since the Preamble on the R-PICH does not contain the IMSI of the MS, this message does not carry the user ID;

Step 5: After receiving the response message, the MS starts to send reverse signaling on the R-TCHs. Since each MS shares the reverse traffic channel, the signaling needs to carry the MS's user identifier IMSI;

The transmit power of the MS is obtained through open-loop power control, that is, the initial power is estimated in an open-loop manner according to the strength of the forward signal, and the power is increased by a certain power step each time during subsequent retransmissions; in order to meet the requirements of a large number of MSs sharing the reverse traffic channel If necessary, multiple R-TCHs can be established, and the MS can randomly select one R-TCHs to send each time it sends signaling;

Step 6: After receiving the signaling, the BTS forwards it to the BSC through the reverse service frame Abis-IS2000TCHReverse;

Step 7: After receiving the signaling, the BSC sends a response to the BTS through the forward service frame Abis-IS2000TCHForward;

Step 8: After the BTS receives the response, it sends a response message BS AckOrder to the MS through the F-TCH, which also carries the user's identifier IMSI;

Step 9: After receiving the response, the MS turns off the transmit power on the R-TCHs for use by other MSs or itself next time.

In the above operation process, the MS sends the reverse signaling after receiving the response message, and the following method can also be used: when the MS sends the Preamble for a period of time, it starts to send the reverse signaling regardless of whether the response is received; If the response message BS Ack Order is not received within a period of time, it is considered that the transmission has failed. In order to prevent multiple MSs from preempting the R-TCHs at the same time, the MS needs to randomly delay for a period of time before retransmitting. If multiple retransmissions fail, the transmission will stop.

In summary, the present invention realizes that the CDMA trunking system can share the reverse service channel, thereby saving system resources and increasing system capacity.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present invention can easily think of changes or Replacement should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (5)

1, a kind of realization shared the method that reverse traffic channel transmits backward signaling, it is characterized in that, comprising:

A, mobile station MS are selected a reverse traffic channel from the reverse traffic channel of having set up, send the backward signaling that has user ID by the reverse traffic channel of selecting;

The response message that has described user ID that B, reception base station controller send.

2, a kind of realization as claimed in claim 1 shared the method that reverse traffic channel transmits backward signaling, it is characterized in that, before MS sent the described backward signaling that has a user ID, described method also comprised:

MS sends lead code makes base transceiver station catch MS;

Base transceiver station is transmitted to base station controller with described lead code.

3, a kind of realization as claimed in claim 2 shared the method that reverse traffic channel transmits backward signaling, it is characterized in that described steps A further comprises:

After base station controller receives described lead code, send response message to MS, MS sends the described backward signaling that has user ID after receiving response message.

4, a kind of realization as claimed in claim 1 shared the method that reverse traffic channel transmits backward signaling, it is characterized in that described method further comprises:

MS sends described backward signaling and finishes, receive response message after, be closed in the transmitting power on the described reverse traffic channel; Or,

MS does not receive response message after sending backward signaling many times yet, then stops automatically.

5, a kind of method that reverse traffic channel transmits backward signaling that realizes sharing as claimed in claim 1, it is characterized in that, the transmitting power that described MS sends backward signaling obtains by open loop power control, initial power is done open loop according to the intensity of forward signal and is estimated, the subsequent retransmissions predetermined electric power step value that at every turn rises.