CN100461901C - A Realization Method of CDMA Digital Trunking Group Call Process - Google Patents

Abstract

A method for realizing a CDMA digital trunking traditional group call conversation process, which is applied to a CDMA digital trunking system. During the group call establishment process, the STDL between the PDS and the BSC in the group dispatching service area is established, and these All BTSs under the BSC establish a shared forward service channel and a shared reverse service channel, and enter the call state; during the call, the terminal that obtains the right to speak sends voice and signaling to the BSS through the time-shared reverse service channel, and the BSS The STDL of this call is transmitted to the PDS; the PDS sends the voice and signaling to the corresponding BSS through all the established STDL of this call, and the corresponding BSS sends the shared forward traffic channel under it, and the terminal is in the shared forward traffic channel. Voice and signaling are received on the forward traffic channel. The method of the invention can meet the needs of a large number of users talking at the same time in the CDMA digital trunking system.

Description

A Realization Method of CDMA Digital Trunking Group Call Process

technical field

The invention relates to a digital trunking system, in particular to a method for controlling group calls and channel resource allocation in the digital trunking system of the CDMA system.

Background technique

Mobile communication technology has been developed to the third generation, among which trunking communication has increasingly become an indispensable communication service. Trunking communication refers to a dedicated dispatching communication method, including dedicated command and dispatching communication. During use, trunking users can join calls at the same time, and calls are made in simplex or half-duplex mode.

Trunking communication has experienced the development process from simple intercom system to single base station small system, and then to large-capacity multi-area system, and then experienced the leap from analog trunking to digital trunking, making trunking communication in signaling coding, using multiple access More reliable digital processing methods can be used in aspects such as mode, voice coding, modulation and demodulation technology, synchronization technology, error detection and error correction and diversity technology. Two digital trunking systems widely used at present are iDEN (integrated Digital Enhanced Network) and TETRA (Terrestrial Trunked Radio) based on TDMA (Time Division Multiple Access) technology. These systems are applied to specific departments and units, all of which belong to dedicated clusters. In order to promote the large-scale application of digital trunking systems and further improve the utilization of frequency resources, a new application trend of The trunking system is combined for unified use and management, so as to achieve the purpose of sharing channels and channels, sharing coverage areas, communication services, and sharing expenses, and finally develops the trunking application from individual professional users to multi-group users to achieve shared network operate.

Calls in the trunking system are usually limited to a certain geographical range. If the trunking terminal exceeds this limit range, the system will not provide trunking call services. This limit range is called the dispatching area. According to the actual needs of network planning, the coverage network of the system can be divided into several dispatch location areas (Dispatch Location Area, DLA). The dispatch location area can be the whole network or a part of the network. As the smallest unit, a cluster call is designated as a dispatch service area (Dispatch Service Area, DSA). The dispatch service area is a collection of dispatch location areas. When a cluster call exceeds the dispatch service area specified by the system, the system will no longer provide services for it.

The development of trunking communication from private network to public network has promoted the research on the realization of trunking technology on the existing GSM (Global System for Mobile Communications, Global System for Mobile Communications) and CDMA (Code Division Multiple Access, Code Division Multiple Access) networks.

The Chinese patent application whose application number is CN200410027538 discloses a control method for the call process of a CDMA2000 digital trunking system. The call process includes: (1) the terminal sends a call establishment request message to request activation of the group; (2) the system calls the terminal The call establishment request is processed; (3) the group enters the conversation state, that is, the group is activated, or the call is successfully established, at this time, the successfully paging terminal can apply for the right to speak; (4) the terminal requests to end the call, and sends a call end request, The system is required to release all resources of this call, and the group is set to be inactive; (5) The system processes the call end request.

This method assigns an air channel separately for each cluster user terminal when performing a cluster call, and the user terminal is paging according to the existing CDMA2000 1X ordinary voice call, that is, by IMSI (International Mobile Subscriber Identity, International Mobile Station Identification Code) ) paging, and when the terminal accesses a call, the channel allocation method for the terminal is also used in the channel allocation method of ordinary voice calls, so that this kind of group call can even break through the geographical restrictions and achieve roaming by independently allocating channels, and the performance is consistent with the current situation. It is different from professional group calling, which is called enhanced group calling in the text.

According to this group call mode, the air interface channel resource occupancy is related to the number of group users. If the number of users is N, the number of channel usage is 2N+1, that is, the air interface resource occupancy increases linearly with the number of users, and the channel resource on the base station side It is limited. In places where a large number of group users are concentrated, such as large-scale sports events, this enhanced group call method cannot meet the requirements.

In addition, a call of this enhanced group call includes the specific process of the terminal side, the base station side, and the network side, and the call control is to control the call process of each terminal. Channel allocation for the terminal also adopts the channel allocation method of ordinary voice calls, so this method must require the terminal to be controlled by the mobile switching center, which increases the signaling interaction with the cluster-independent network elements.

Contents of the invention

The technical problem to be solved by the invention is to propose a method for realizing the CDMA digital trunking group call process, which can meet the needs of a large number of users for simultaneous calls.

In order to solve the above-mentioned technical problems, the present invention provides a kind of realization method of CDMA digital trunking group call process, is applied to the digital trunking system of CDMA standard, and this method comprises the following steps:

(a) During the group call establishment process, establish a dedicated shared trunking data link between the dispatching server and the base station subsystems in the group dispatching service area, and establish a shared forward link on all transceivers in these base station subsystems The traffic channel and the shared reverse traffic channel enter the conversation state, wherein the shared forward traffic channel established under a base station transceiver includes a shared forward basic traffic channel and a shared forward supplementary traffic channel, and the base station subsystem passes The forward basic service channel sends voice to the terminal side, or voice plus signaling, and sends signaling to the terminal side through the shared forward supplementary service channel;

(b) During the call, the terminal that obtains the right to speak sends voice and signaling to the base station subsystem through the time-sharing reverse traffic channel, and the base station subsystem transmits the voice and signaling through the dedicated shared cluster data link of this call The signaling is transmitted to the scheduling server;

(c) The dispatching server sends the voice and signaling to the corresponding base station subsystem through all the established dedicated shared cluster data links of this call, and the corresponding shared forward traffic channel of the transceiver of the base station subsystem sends the For the voice and signaling, the terminal receives the voice and signaling on the shared forward traffic channel.

Further, the above implementation method may also have the following characteristics: in the step (a), the shared reverse traffic channel established under a base transceiver station includes at least two shared reverse basic traffic channels, during the conversation, The terminal that has obtained the speaking right occupies a time-sharing shared reverse basic service channel to send reverse signaling and voice to the base station subsystem, and all the terminals that do not have the speaking right use one or more simultaneously shared reverse basic service channels to send Reverse signaling.

Further, the above implementation method may also have the following characteristics: during the conversation, the terminal that obtains the speaking right sends the voice to the base station subsystem through the exclusive time-sharing shared reverse traffic channel, and the base station subsystem transmits the voice to the base station subsystem through a dedicated shared digital trunking The data link is sent to the dispatching server, and the dispatching server forwards the voice to all base station subsystems that have established the dedicated shared digital trunking data link for this call, and these base station subsystems then send the voice through the shared forward basic service channel , received by the terminal itself on the shared forward basic service channel.

Further, the above-mentioned implementation method may also have the following characteristics: the application for the right to speak is completed through the following steps during the call:

(h) The user sends the speaking right application signaling through the terminal held by the user, and the application signaling is sent to the base station subsystem through the reverse basic service channel shared at the same time, and then sent to the dispatching server through the dedicated shared digital trunking data link;

(i) After the dispatching server receives the application signaling, it judges whether it has the right to speak according to the information obtained from the dispatching home register when the call is established. If the terminal has the right to speak and its priority is among the terminals applying for the right to speak highest, then send a speaking authorization instruction to the base station subsystem where the terminal is located via the dedicated shared digital trunking data link, and send the instruction on the shared forward supplementary traffic channel corresponding to the transceiver of the base station subsystem, and the terminal will the indication is received on the channel;

(j) After the terminal receives the speaking authorization instruction, it sends the speaking right confirmation signaling to the base station subsystem on the exclusive time-sharing shared reverse basic service channel, and the base station subsystem sends the This signaling is sent to the dispatch server.

Further, the above implementation method may also have the following features: after the step (j), it also includes a step (k): after the dispatching server receives the confirmation of the right to speak, it sends a prompt of "there is a user speaking" to all non-speaking users in the call , the prompt is first sent to all base station subsystems that have established a dedicated shared digital trunking data link for this call with the dispatching server, and is sent on the shared forward supplementary traffic channel corresponding to the transceiver of the base station subsystem, and the terminal Receive the prompt yourself on that channel.

Further, the above-mentioned implementation method may also have the following characteristics: the release of the right to speak is completed through the following steps during the call:

(o) When a user with the right to speak wants to give up the right to speak, the operating terminal sends an application signaling for releasing the right to speak to the scheduling server, and the release application signaling is sent to the base station subsystem through the time-sharing shared reverse basic service channel it has monopolized , and then sent to the dispatching server through the dedicated shared digital trunking data link, and then the terminal exits its exclusive reverse channel;

(p) When the dispatching server receives the release application, it sends a speech right release confirmation signaling to the base station subsystem where the terminal is located via the dedicated shared digital trunking data link, and the corresponding shared The signaling is sent on the forward supplementary traffic channel, and the terminal receives the signaling on the channel.

Further, the above-mentioned implementation method may also have the following characteristics: step (q) is also included after the step (p): the dispatching server sends a "no user to speak" prompt to all users in the call, and the prompt is first sent to all dispatchers and dispatchers. The server establishes the base station subsystem of the dedicated shared digital trunking data link for this call, and sends it on the shared forward supplementary service channel corresponding to the transceiver of the base station subsystem, and the terminal receives the prompt on this channel by itself.

Furthermore, the above implementation method may also have the following characteristics: when the step (a) enters the talking state, the dispatching server grants the speaking right to the calling terminal by default.

As can be seen from the above, the method of the present invention adopts the channel sharing method of the traditional group call in the way of channel resource allocation, so that the digital trunking system originally limited to the number of users in the community becomes an unlimited number of single group users system, greatly improving the system capacity of cluster communication. Furthermore, through the reasonable allocation of channel resources, the system congestion probability of trunking communication is reduced, and a large number of users can be accommodated at the same time.

Description of drawings

Fig. 1 is a network structure diagram of a method in an embodiment of the present invention.

Fig. 2 is a flow chart of updating terminal information in the method of the embodiment of the present invention.

Fig. 3 is a flow chart of call establishment in the method of the embodiment of the present invention.

Fig. 4 is a flow chart of member conversation in the method of the embodiment of the present invention.

Fig. 5 is a flow chart of call release in the method of the embodiment of the present invention.

Detailed ways

The present invention will be further introduced below in conjunction with the accompanying drawings and specific embodiments, but it is not intended to limit the present invention.

With reference to shown in Fig. 1, it is a network structure diagram supporting the CDMA digital trunking traditional group call control method of the present invention, and its main components are first introduced as follows:

MS: Trunking terminal, also referred to as terminal in this article, is a terminal device capable of storing user information, group information, scheduling area judgment, and responding to trunking services such as traditional group calling and paging.

BSS: Base station subsystem, including a transceiver (BTS) that supports trunking calls, a base station controller (BSC) and a dispatch client (PDC) that interacts with the network side;

PDS: Dispatch server to realize call control and talk right management of group calls;

PHR: Scheduling belonging register, which saves the registration information and location information of cluster users and groups, and realizes the authentication, authorization and billing functions of cluster users, as well as the location update and group management functions.

In this document, the PDS and the PHR are collectively referred to as the network side or the dispatching system. The system side includes the base station subsystem and dispatching system.

In order to realize unlimited capacity and fast access, the present invention adopts a resource allocation method of sharing wireless channels. In the PCT international application with the publication number WO2004/110085 A1, a cluster communication method of the CDMA2000 mobile communication system is disclosed. The base station system allocates a common forward traffic channel for the same group under the same cell, and the group terminal uses The common long code mask monitors the common forward service channel, and uses a shared service channel in the reverse direction to provide reverse service support for group terminals through scheduling. This patent focuses on establishing the forward and reverse shared channels on the wireless side, that is, between the terminal and the base station, and the way the terminal captures the forward shared service channel to access the call, but in fact, this resource allocation method is still difficult to use in actual calls. application (which will be discussed below), and the patent application does not involve the control methods of the terminal side, the base station side and the network side in the group call process. For example, how many forward and reverse shared traffic channels are established between the base station side and the terminal side, how to implement signaling and voice interaction between the network side and the terminal side, and so on.

In order to distinguish it from the enhanced group call mode of the existing CDMA system trunking system, the call mode of the present invention is called traditional group call in the text. Before introducing the implementation method of the traditional group call process of the present invention, the relevant terminal information update process and call establishment process are introduced first.

Terminal information update process

In order to improve the access speed of the system, to realize functions such as group call terminal responding to paging according to the group identifier (GID) and realizing restricted calls in the dispatching area, it is necessary to record corresponding information on the terminal and the information on the terminal needs to be consistent with the content recorded in the PHR To be consistent, after PHR adds, deletes and modifies the information corresponding to the terminal, it needs to update the terminal information accordingly, or it is called information synchronization.

The terminal information update process of this embodiment is shown in Figure 2, including the following steps:

Step 201: MS initiates a location registration request for trunking services;

To update the information, the terminal needs to be in the idle state, and the PDS will page it into the PTT service state before proceeding. If the terminal based on the CDMA2000 technology is in a business state (the business state includes: ordinary CDMA1X voice service, data service, PTT (Push-To-Talk) service), sending a message with a large amount of information on the control channel will be very slow, so It leads to occupying resources for too long, and if the existing service channel of the terminal is used to send the update information, it will lead to the confusion of functions and affect the release of the basic call. Because a terminal based on CDMA technology must be out of service if it can perform location registration, this embodiment takes the location registration initiated by the terminal as the starting point of the terminal information update process.

Step 202: The PHR returns a location update registration acceptance message to the MS via the PDS;

This message notifies the MS that the registration is successful, and a corresponding icon may be displayed on the terminal interface as success.

Step 203: The PHR judges whether the information change flag of the MS is set, if it is set, it means that the MS needs information update, and sends the terminal information update notification of the MS to the PDS;

Whether the information change flag of the MS is set depends on whether the information stored in the PHR that needs to be updated by the MS is changed. If the information related to the MS is changed, the flag is set.

Step 204: After the server PDS receives the terminal information update notification from the PHR, if the MS is in an idle state, it initiates paging to the user;

The paging here is an enhanced paging, because this update is only for this user.

Step 205: The MS returns a paging response to the system, and the BSS system establishes a traffic channel for it, and notifies the PDS of the completion of the traffic channel establishment;

The service channel established by the system for this MS is also an enhanced type, which is exclusively occupied by this MS.

Step 206: After the PDS learns that the service channel of the updated user is established, it requests the PHR for update information;

Step 207: The PHR returns to the PDS the terminal information that needs to be modified by the MS;

The terminal information is divided into user information and group information. The user information mainly includes the scheduling area to which the MS belongs, Do Not Disturb, MDN (Mobile Directory Number, mobile phone number) information, etc. The group information mainly includes the GID of the group, GMDN ( Group MDN, group mobile phone number), group name, member priority, group scheduling area, etc. User information and group information are independent of each other and can be updated separately.

Step 208: The PDS sends a terminal information update request message to the MS, carrying terminal information to be modified;

Step 209: The MS returns a terminal information update response message to the PDS after performing corresponding add, modify, and delete operations according to the requirements in the terminal information update request message, and carries the updated result;

Step 210: After receiving the terminal information update response message returned by the MS, the PDS notifies the PHR that the terminal information update is completed;

Step 211: the PDS sends a release message to the MS;

Step 212: MS returns a release response and sends a release complete message to the BSS;

Step 213: After receiving the release completion message of the terminal, the BSS releases the radio side resources and returns a release completion message to the PDS to complete the terminal information update.

In some special cases, for example, during dynamic reorganization, terminal information needs to be updated in time when individual users in the group are deleted. The trigger point of this update can be learned by the PDS, and when it judges that the MS is not in the service state, it initiates paging to the user, and then performs step 205, and the subsequent steps are the same as the above-mentioned process.

call setup process

Before the MS calls, the BSS has been sending overhead messages to the MS. For MSs that support traditional group calls, the base station needs to send overhead messages, and the MS will only be considered to have captured the system when it receives the message. The overhead message will include the scheduling location area. Information (DLA). The MS sets a service identifier for each group. After receiving the overhead message, it compares the DLA in the message with the dispatching service area (DSA) supported by each group in the group information stored locally. If the MS is currently in If the DLA belongs to the DSA of a certain group, set the service identifier of the group as "servable".

The call establishment process in the method of this embodiment is shown in Figure 3, wherein the interaction process between the network side and the base station side includes the following steps:

Step 301: The caller selects a group that supports the current dispatching area of the terminal (that is, the group identified as "servable") to initiate a call, and the caller terminal sends a call request to the BSS;

The traditional and enhanced resource allocation methods mentioned above are transparent to the user, because these two calls are actually different resource allocation methods on the system side, and the user does not need to know the difference. Therefore, the user's call on the terminal The operation and calling method are the same. Of course, since the current dispatch location area of the terminal will be used later, the value of the current dispatch location area will be included in the calling signaling.

If the user selects a group that does not support the current scheduling area of the terminal, the terminal side can prompt an error message, or try to access, and the network side will also make a judgment on this.

Step 302: The call request is sent to the PDS via the BSS, and the PDS requests the PHR for authentication and receives the authentication result;

The authentication of the call in the PHR is mainly to judge whether the terminal has the right to initiate a call, and whether it is in the group it wants to initiate a call. If there are both traditional and enhanced group attributes, when returning the authentication result to the PDS, the PDS should also be notified of the attributes of the paging group.

Step 303: After the PDS receives the authentication result returned by the PHR, if the caller is a traditional group, continue to judge whether the dispatching area where the terminal is currently located is in the dispatching service area of the group returned by the authentication, and if so, then The PDS can call this group, send a traditional group call paging request with calling information to the BSC where the caller is located, and send a paging request without calling information to all non-calling BSCs in the dispatching service area of the group traditional group paging request;

If the dispatching location area where the terminal is currently located is not in the dispatching service area of the group returned through authentication, the call is rejected. However, in another embodiment, if the system incorporates the function of the enhanced group call, it can also provide services for it, that is, provide the function of unlimited dispatching area.

The so-called "traditional" group call paging request (with GID) here just means that the paging request indicates that the call is a traditional group call, and the BSC will establish a wireless channel according to the resource allocation method of the traditional group call. The difference between the paging request with caller information and without caller information is that the paging request with caller information includes the information of the originating terminal, and the BSC receives a traditional group call with caller In addition to the common shared channel, it also informs the calling terminal that it can use the time-sharing shared reverse basic service channel.

Step 304: After receiving the group call paging sent by the PDS, the BSC requests the PDS to establish a dedicated shared trunking data link (STDL) for this call. Dedicated shared cluster data link;

The shared trunking data link is the bearer of voice forwarding in the CDMA trunking system, and its life cycle is the same as that of the current call, that is, this STDL will not be released until the end of the group call. If there is an abnormal release, the base station side and the network side will monitor and rebuild at any time.

On the other hand, the BSC notifies all BTSs under it to establish wireless channel resources, including 1 forward basic service channel, 1 forward supplementary service channel and 2 reverse basic service channels. After the BTS wireless channels under the BSC are successfully established , notify the PDS through the establishment completion message, and at the same time, periodically broadcast and send the group paging message addressed by the GID on the paging channel;

MS receives the paging message, after judging that it is a traditional group paging paging, it matches the GID in the paging with the GID in the stored group information, if the match is successful, it uses the long code mask in the paging signaling Such information captures the established forward basic service channel and forward supplementary service channel for the group in the area to which it belongs, and automatically accesses the group without returning enhanced access response signaling to the BSS;

That is, the BSS only needs to send a traditional group paging paging message (that is, a broadcast channel assignment message) on the paging channel, regardless of whether the called party accesses or not.

Step 305: The PDS receives the establishment completion message of the originating BSC, the call is established successfully, and enters the conversation state, and the PDS notifies the PHR to start charging.

As long as the calling BSC completes the establishment of the wireless channel and STDL, it can be considered that the call has been established, because there may be multiple group users under the BSC who will be called.

Through the above process, the shared forward traffic channel and the shared reverse traffic channel between the BSS and the terminal side, and the dedicated shared cluster data link between the BSS and the PDS have been established. How to use these channels to transmit signaling and voice, and how to control the call process, can effectively use these resources and realize simultaneous calls of a large number of users, which are the concerns of the present invention.

In this embodiment, the BSS uses the established forward basic service channel to send voice, and uses the forward supplementary service channel to send signaling. Sending voice and signaling separately can avoid signaling conflicts caused by sending a large amount of voice data, resulting in communication failure. However, in another embodiment, according to the voice data traffic, the BSS may also package and send the signaling to be sent to the terminal while sending the voice to the terminal through the basic service channel.

In the reverse direction, one of the two reverse basic service channels is shared by all the terminals under a BTS without the speaking right during the conversation, so as to send reverse signaling, such as speaking right application signaling. The other is time-sharing, which is temporarily monopolized by the terminal that has obtained the speaking right to send the terminal's voice and reverse signaling. In this way, signaling conflicts on the same channel can be avoided when a large amount of voice data is sent. In another embodiment, more reverse basic service channels can be established to accommodate more terminal access calls.

For the calling terminal, there is no need to apply for the speaking right when the group call is just established, and the PDS will grant the speaking right to it by default according to the PTT (Push To Talk) principle after the group call is established. The system then sends the user's voice to the various endpoints that receive the call. In this embodiment, the voice transmission during the call is completed in the following ways:

Step 1: After the call is established, the calling terminal that has obtained the right to speak monopolizes a time-shared reverse basic service channel to send reverse signaling and voice;

Step 2: After the voice is sent to the BSS, the BSS sends it to the PDS through a dedicated shared digital trunking data link;

Step 3, the PDS is forwarded to all BSSs that have established the dedicated shared digital trunking data link for this call, and the BSS sends it to the terminal through the shared forward basic service channel under it;

Specifically, the PDS is first forwarded to the BSC, and the BSC then distributes the voice to all BTSs that have established shared channel resources for this call, and the BTS sends the voice through the shared forward basic service channel.

Step 4, the terminal receives the voice by itself on the forward shared basic service channel.

During the call, the right to speak can be released and applied for, and the applicant for the right to speak can obtain the right to speak after three parties interact on the terminal side, the base station side, and the network side. Assume that MS_A is the terminal held by user A, who applies for and temporarily obtains the right to speak during the call, and MS_B represents all terminals that do not have the right to speak temporarily. As shown in Figure 4, this embodiment implements the above process through the following steps:

Step 401, user A sends the speaking right application signaling through the terminal MS_A held by the user, and the speaking right application signaling is sent to the BSS through the reverse basic service channel shared at the same time, and the BSS sends it to the PDS through the dedicated shared digital trunking data link;

Step 402: After receiving the application signaling, the PDS judges whether it has the right to speak according to the information obtained from the PHR when the call is established. If the terminal has the right to speak and has the highest priority among the terminals applying for the right to speak, the PDS Send a speaking authorization instruction to MS_A, after the instruction is sent to the BSS where MS_A is located via STDL, the BSS sends it on the shared forward supplementary service channel under it, and MS_A receives the signaling on this channel by itself;

It should be noted that the conversation of members is limited by the conversation state machine. The essence of the conversation state machine is a queuing mechanism based on the priority of the speaking right in the user group. If there are multiple terminals applying for the speaking right, the speaking right will be granted to the pre-set The terminal with the highest right priority, usually the caller is ranked first, and the right to speak is granted to it in time.

Step 403: MS_A returns an authorization confirmation to the PDS. At this time, MS_A has monopolized a time-shared reverse basic service channel, which is still transmitted between the BSS and the network side through a dedicated shared digital trunking data link;

Step 404: After receiving MS_A's right to speak confirmation, the PDS sends a "user is speaking" prompt to all non-speaking users in the call. In a traditional group call, this prompt will be sent to all parties who have established this call with the PDS according to the GID The BSS of STDL is sent by the BSS on the shared forward supplementary service channel under it, and the terminal receives the prompt on this channel by itself;

The voice and signaling transmission mode of user A talking through MS_A has been mentioned in the description of the calling terminal above, and will not be repeated here;

Step 405: When user A wants to release the speaking right, operate MS_A to send a signaling for releasing the speaking right to the PDS. The transmission path of the signaling is the same as the signaling for applying for the speaking right, and then exit its exclusive reverse channel;

Step 406: The PDS sends a confirmation signaling to the MS to release the session right, and the transmission path of the signaling is the same as that of the authorization indication signaling;

Step 407: The PDS sends a "no user speaking" prompt to all users in the call, and the transmission path of the signaling is the same as that of the "user is speaking" prompt signaling.

It can be seen from the above steps that during the call, the base station subsystem (BSS) is controlled by the network side, and there is no need to establish a point-to-point PPP connection directly to the terminal, thus reducing the connection time. At the same time, the complete sharing of the channel realizes the terminal unlimited capacity. Therefore, it can meet the requirements of a large number of users talking at the same time.

It should be noted that the process of applying for and releasing the speaking right is not necessary in one call.

Let's introduce the call end process again

Call release may be initiated by multiple parties, and the initiators can be divided into terminal side, base station side, and network side. Here, the release initiated by the terminal is taken as an example. Assume that MS_A is the terminal held by user A and initiates the release during the call, and MS_B represents all terminals that do not have the right to speak temporarily. As shown in Figure 5, the call ending process includes the following steps:

Step 501: When user A wants to end the group call, operate MS_A to send a call release request, which is forwarded to the PDS via the BSS;

Step 502: After the PDS receives the release request, if the user has the right to release the group call, it sends a call release instruction to all BSCs in this call;

The enhanced end signaling is actually sent to each terminal in the group, while the network side of the traditional group call controls the base station instead of the terminal, so that the release instruction is actually notified to the base station side instead of the same notification as the enhanced type For each member in the group, the calling BSC and the non-calling BSC are no longer distinguished when released.

Step 503: After the BSC receives the call release instruction from the PDS, it notifies all the BTSs under it to send the call end notification to the supplementary traffic channel, release the air interface resources, and apply to the PDS for releasing the dedicated shared trunking data link for this call ( STDL);

The call end notification is received by the terminal itself on the forward supplementary traffic channel.

When the BSC releases the air interface resources, it notifies all the BTSs under it to cancel the forward shared channel allocated for this call. The channel automatically exits the service state. The MS_B that withdraws from this call can accept other paging again after going through the pilot frequency and synchronization process required by CDMA.

Step 504: The PDS responds to the STDL release request of the BSS, and no longer forwards the voice;

Step 505: After the air interface resources and the STDL link are released, the BSC returns a release complete message to the PDS;

Step 506: After receiving the release completion message of all BSCs for this call, the PDS clears the resources on the network side, notifies the PHR of the release of this call, and ends the charging.

When the call release is initiated by the base station, especially when the BSC finds that the wireless side of the call is abnormal, it will apply to end the traditional group call, and the processing of the PDS after receiving the request is the same as the above steps 502-506. The same is true when the call release is initiated by the dispatcher or PDS on the network side.

Claims (8)

1. an implementation method of CDMA digital trunking group call process, applied to the digital trunking system of CDMA system, it is characterized in that, the method may further comprise the steps: a. During the group call establishment process, establish a dedicated shared trunking data link between the dispatching server and the base station subsystems in the group dispatching service area, and establish a shared forward service on all transceivers in these base station subsystems channel and the shared reverse traffic channel, and enter the conversation state, wherein the shared forward traffic channel established under a base transceiver station includes a shared forward basic traffic channel and a shared forward supplementary traffic channel, and the base station subsystem passes the The forward basic service channel sends voice to the terminal side, or voice plus signaling, and sends signaling to the terminal side through the shared forward supplementary service channel; b. During the call, the terminal that has obtained the right to speak sends voice and signaling to the base station subsystem through the time-sharing reverse traffic channel, and the base station subsystem transmits the voice and signaling through the dedicated shared cluster data link of this call The command is transmitted to the dispatch server; c. The dispatching server sends the voice and signaling to the corresponding base station subsystem through all the established dedicated shared cluster data links of this call, and the shared forward traffic channel corresponding to the transceiver of the base station subsystem sends the The voice and signaling, the terminal receives the voice and signaling on the shared forward traffic channel. 2. The implementation method as claimed in claim 1, wherein in said step a, the shared reverse traffic channel set up under a base transceiver station comprises at least two shared reverse basic traffic channels, during a call , the terminal that obtains the right to speak exclusively occupies a time-sharing shared reverse basic service channel to send reverse signaling and voice to the base station subsystem, and all terminals in the group that do not have the right to speak use one or more reverse basic service channels shared at the same time Send reverse signaling. 3. The realization method as claimed in claim 2, characterized in that, during the conversation, the terminal that obtains the right to speak sends the voice to the base station subsystem through the exclusive time-sharing shared reverse traffic channel, and the base station subsystem transmits the voice to the base station subsystem through a dedicated shared digital channel. The trunking data link sends the voice to the dispatching server, and the dispatching server forwards the speech to all base station subsystems that have established the dedicated shared digital trunking data link for this call, and these base station subsystems then share the forward basic service channel The voice is sent and received by the terminal itself on the shared forward basic service channel. 4. The implementation method according to claim 2, characterized in that, the application for speaking right is completed through the following steps during the conversation: h. The user sends the speaking right application signaling through the terminal held by the user, and the application signaling is sent to the base station subsystem through the reverse basic service channel shared at the same time, and then sent to the dispatching server through the dedicated shared digital trunking data link; i. After the dispatching server receives the application signaling, it judges whether it has the right to speak according to the information obtained from the dispatching home register when the call is established. If the terminal has the right to speak and its priority is the highest among the terminals applying for the right to speak , then send a speaking authorization instruction to the base station subsystem where the terminal is located via the dedicated shared digital trunking data link, and send the instruction on the shared forward supplementary traffic channel corresponding to the transceiver of the base station subsystem, and the terminal is on the Receive the indication on the channel; j. After receiving the speaking authorization instruction, the terminal sends a speaking right confirmation signaling to the base station subsystem on the exclusive time-sharing shared reverse basic service channel. The signaling is sent to the dispatch server. 5. The implementation method according to claim 4, characterized in that, after step j, step k is further included: after the scheduling server receives the right to speak confirmation, it sends a prompt of "there is a user speaking" to all non-speaking users in the call , the prompt is first sent to all base station subsystems that have established a dedicated shared digital trunking data link for this call with the dispatching server, and is sent on the shared forward supplementary traffic channel corresponding to the transceiver of the base station subsystem, and the terminal Receive the prompt yourself on that channel. 6. The implementation method according to claim 2, characterized in that, the release of the right to speak is completed through the following steps during the conversation: o. When a user with the right to speak wants to give up the right to speak, the operating terminal sends an application signaling for releasing the right to speak to the scheduling server, and the release application signaling is sent to the base station subsystem through the time-sharing shared reverse basic service channel that it has monopolized, Then send it to the dispatching server through the dedicated shared digital trunking data link, and then the terminal exits its exclusive reverse channel; p. When the dispatching server receives the release application, it sends a speech right release confirmation signaling to the base station subsystem where the terminal is located via the dedicated shared digital trunking data link. and sending the confirmation signaling to the terminal on a supplementary traffic channel. 7. The implementation method according to claim 6, characterized in that, after the step p, step q is also included: the dispatching server sends a "no user to speak" prompt to all users in the call, and the prompt is first sent to all dispatchers and dispatchers. The server establishes the base station subsystem of the dedicated shared digital trunking data link for this call, and sends it on the shared forward supplementary service channel corresponding to the transceiver of the base station subsystem, and the terminal receives the prompt on this channel by itself. 8. The implementation method according to claim 1, characterized in that, when the step a enters into a talking state, the scheduling server grants the speaking right to the calling terminal by default.

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