CN103687043A - A method for establishing a radio resource control protocol connection - Google Patents

Abstract

The invention discloses a method of setting up a radio resource control protocol connection. The method comprises the following steps: cluster UE (User Equipment) sends a RRC (Radio Resource Control) protocol connection request and carries user access instruction information in an Msg3 corresponding to the RRC connection request; an eNB (evolved Node B) receives the Msg3, and confirms that the UE grains access to a cluster group calling service according to the user access instruction information; the eNB sends the RRC connection setup message to the UE and distributes an uplink resource for the UE; the cluster UE is configured according to the RRC connection setup message, and transmits the RRC connection setup complete message according to the uplink resource. By the application of the method, the time for setting up the RRC connection can be shortened.

Description

A method for establishing a radio resource control protocol connection

technical field

The present application relates to the field of communication technologies, and more specifically, to a method for establishing a radio resource control protocol connection (RRC).

Background technique

The broadband multimedia trunking system based on TD-LTE technology can not only support various multimedia services of the TD-LTE mobile communication system itself, but also provide basic trunking call services and trunking multimedia services, such as voice group calls, voice single calls, video Services such as group call, video individual call, web browsing, mobile office, video surveillance, video playback, and video conferencing. In these services, trunking communication has extremely strict requirements on the time for group call establishment. In order to achieve the purpose of fast establishment of group call service, it is necessary to take a series of measures to guarantee the broadband multimedia trunking system based on TD-LTE technology.

When a trunking user (UE) in an idle state initiates a group call, it triggers an RRC connection establishment process to establish an RRC connection. Referring to accompanying drawing 1, it is a schematic diagram of the successful establishment of the RRC connection in the LTE system, which mainly includes three steps:

Step 101, the UE sends an RRC Connection Request (RRC Connection Request) message on the Signaling Radio Bearer (SRB) 0 through the uplink common control (UL-CCCH) channel, which mainly carries information such as the initial user identity of the UE and the establishment reason. The high-level message triggers the low-level entity of the UE to perform a contention-based random access process, and the RRC connection request message corresponds to Msg3 in the low-level random access process.

Step 102, eNode B replies with an RRC Connection Setup (RRC Connection Setup) message on SRB0 through the downlink common control (DL-CCCH) channel, which usually corresponds to Msg4 in the low-level random access process, which carries the complete information of SRB1 Configuration information, including configuration parameters of each entity such as PHY/MAC/RLC/PDCP.

Step 103: After configuring SRB1 according to the RRC connection establishment message, the UE sends an RRC Connection Setup Complete (RRC Connection Setup Complete) message on SRB1 through the UL-DCCH channel, which carries an initial NAS message in the uplink direction, such as Attach Request, TAU Request, ServiceRequest, Detach Request, etc. After receiving the RRC connection establishment completion message, the eNode B forwards the NAS message to the mobility management entity (MME) to establish the S1 connection.

Random access is a necessary step for establishing a wireless link between the UE and the network. In the LTE system, random access is divided into contention random access and non-contention random access. Contention random access means that the eNode B does not assign a dedicated Preamble code to the UE, but the UE randomly selects the Preamble code and initiates random access. In the scenario of initial access in RRC IDLE state (that is, RRC connection establishment), UE autonomously triggers contention random access, and eNode B does not have any prior information.

Accompanying drawing 2 is the schematic diagram of contention random access procedure in LTE system, mainly includes four steps:

In step 201, the UE randomly selects a random access Preamble code on an uplink random access channel (PRACH) and sends it in a message (Msg) 1 .

In step 202, the eNode B transmits the random access response generated by the MAC layer, that is, Msg2, on the DL-SCH channel.

In step 203, the UE transmits the scheduling information of the first uplink transmission, that is, Msg3, on the UL-SCH channel.

After receiving Msg2 correctly, the UE transmits Msg3 according to the uplink resource allocated to it in the uplink grant in the random access response. For different scenarios, Msg3 contains different content. In the initial access scenario, the RRC connection request message generated by the RRC layer will be carried, and the NAS message will not be included.

In step 204, the eNode B transmits contention resolution information, namely Msg4, on the DL-SCH channel.

Only after the random access procedure is completed, can the eNode B and UE perform regular data transmission and reception. When a UE requests uplink resources for a new transmission from the eNode B, the UE needs to send a Scheduling Request (SR). The SR is triggered by the BSR. When the regular BSR is triggered but no uplink resource is available, the UE will send the SR. For the RRC Connection Setup Complete (RRC Connection Setup Complete) message sent by the UE, the UE usually needs to send an SR. SR has the following two forms:

(1) Dedicated SR: The eNode B allocates specific PUCCH resources for the UE to send scheduling requests, and the dedicated SR is periodically valid. When the UE needs to send an SR, if a dedicated SR is configured, the dedicated SR will be used preferentially, and when the subframe of the dedicated SR arrives, the sending of the dedicated SR will be triggered.

(2) Random access SR: If no dedicated SR resources are assigned to the UE, or if the uplink scheduling from the eNode B is not received when the dedicated SR transmission reaches the maximum number of transmissions, the UE will stop using the dedicated SR and use random access SR . In this way, the UE can send the BSR to the eNode B through the random access procedure. The random access SR adopts the random access process of competition, and the BSR will be sent to the eNode B in Msg3.

When the trunking UE in the idle state initiates a group call, it will trigger an RRC connection establishment process to complete the RRC connection establishment. During the establishment of a successful RRC connection, the UE needs to send two messages to the eNode B successively. For the RRC connection request message, after receiving the Msg2 correctly, the UE transmits according to the uplink resource allocated to it in the uplink grant in the random access response. For the RRC connection establishment completion message, Msg4 in the LTE protocol does not carry an uplink authorization like Msg2, and usually the UE needs to send an SR. If the UE is configured with a dedicated SR, it needs to wait until the arrival of the subframe of the dedicated SR to trigger the sending of the dedicated SR. After receiving the SR, the eNode B will send an uplink authorization to allocate few uplink resources for the UE to transmit BSR. After receiving the BSR sent by the UE, the eNode B allocates uplink resources to it according to the amount of logical channel buffer data reported by the UE. The UE then completes the transmission of the RRC connection establishment completion message according to the uplink resource allocated to it by the uplink grant.

It can be seen that there is a certain processing delay in the process from receiving the RRC connection establishment message to sending the RRC connection establishment complete message by the UE. If the UE is not configured with a dedicated SR or has not received the uplink scheduling from the eNode B when the dedicated SR has been sent to the maximum number of transmissions, the UE will stop using the dedicated SR and use a random access SR. Sending to eNode B also has processing delay.

Contents of the invention

The embodiment of the present invention proposes a method for establishing a radio resource control protocol connection, which shortens the time for establishing an RRC connection.

The technical scheme of the embodiment of the present invention is as follows:

A method for establishing a radio resource control protocol connection, the method comprising:

The cluster user UE sends a radio resource control protocol RRC connection request, and carries information indicating user access in a message Msg3 corresponding to the RRC connection request;

The base station eNB receives the Msg3, and determines that the UE accesses the trunking group call service according to the indicated user access information;

After the eNB sends an RRC connection establishment message to the UE, it allocates uplink resources for the UE;

The cluster UE is configured according to the RRC connection establishment message, and transmits the RRC connection establishment complete message according to the uplink resource.

Said carrying the information indicating user access includes carrying the information indicating user access through a reserved bit of the information element of the RRC connection request.

The carrying the information indicating user access includes carrying the information indicating user access through a reserved value of the establishment cause.

The carrying information indicating user access includes indicating user access information by establishing emergency in the cause.

The allocating the uplink resource for the UE includes: allocating the uplink resource for the UE by sending an uplink grant.

The allocating uplink resource for the UE by sending the uplink grant includes: allocating the uplink resource for the UE by sending the uplink grant on the physical downlink control channel PDCCH.

After the eNB sends an RRC connection establishment request message to the UE, allocating uplink resources for the UE includes: the eNB first sends an RRC connection establishment request to the UE, and allocates uplink resources for the UE after an interval T, T≥T1+T2+T3, T1 is The time for the UE to parse the RRC connection establishment request, T2 is the time for the UE to configure the signaling radio bearer SRB1, and T3 is the time for assembling the RRC connection establishment complete message.

The configuration of the cluster UE according to the RRC connection establishment message includes: the cluster UE monitors the PDCCH, and performs configuration according to the RRC connection establishment message.

The configuration of the cluster UE according to the RRC connection establishment message includes: the cluster UE configures SRB1 according to the RRC connection establishment message.

It can be seen from the above technical solutions that in the embodiment of the present invention, the cluster UE sends an RRC connection request including user access information, and carries the user access information in Msg3 corresponding to the RRC connection request; eNB receives the Msg3, determine that the UE accesses the trunking group call service according to the user access information; after the eNB sends the RRC connection establishment message to the UE, allocates uplink resources for the UE; the UE configures according to the RRC connection establishment message, and transmits RRC according to the uplink resources Connection establishment complete message. The cluster UE does not need to send a scheduling request, but can send an RRC connection establishment completion message on the corresponding uplink resource in advance, shortening the time for establishing the RRC connection and speeding up the establishment of the RRC connection.

Description of drawings

FIG. 1 is a schematic diagram of a successful RRC connection establishment process in an LTE system;

FIG. 2 is a schematic diagram of a contention random access process in an LTE system;

FIG. 3 is a schematic flowchart of a method for establishing a radio resource control protocol connection;

Fig. 4 is a schematic flow diagram of eNB receiving Msg3 sent by UE.

Detailed ways

In order to make the object, technical solution and advantages of the present invention more clearly, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

In the embodiment of the present invention, the cluster UE sends an RRC connection request, and the RRC connection request triggers the underlying entity of the UE to perform a contention-based random access process, and carries information indicating user access in Msg3 corresponding to the RRC connection request; eNB receives The Msg3 determines that the UE accesses the cluster group call service according to the user access information; the eNB allocates uplink resources for the UE after sending the RRC connection establishment message to the UE; the UE configures according to the RRC connection establishment message, and according to the uplink resource An RRC connection establishment complete message is transmitted. In this way, the cluster UE does not need to send a scheduling request, but can send an RRC connection establishment completion message on the uplink resource allocated to it in advance, which speeds up the time of the RRC connection establishment process and further accelerates the establishment of the cluster group call.

In the broadband multimedia trunking system based on TD-LTE technology, when the trunking UE in the idle state (RRC-Idle) initiates a group call call, the RRC connection establishment process is triggered to establish an RRC connection, and the trunking UE is converted from the RRC-Idle state It is the RRC-Connection state. The RRC connection establishment process involves a random access process in which lower layers compete.

The cluster UE sends an RRC connection request message, which corresponds to Msg3 in the lower layer random access procedure. The cluster UE will carry information that can indicate user access in Msg3, so that the eNodeB can learn the establishment reason of the UE. The eNode B obtains the user access information according to the user access information carried in the contention random access process Msg3, and determines that the user wants to access the trunking group call service. After the eNode B sends the Msg4 corresponding to the RRC connection establishment message, Then send the uplink grant to allocate uplink resources for the UE. The cluster UE can send an RRC connection establishment complete message without sending a scheduling request.

Referring to accompanying drawing 3, it is a schematic flowchart of a method for establishing a radio resource control protocol connection, which specifically includes the following steps:

Step 301, the trunking UE sends an RRC connection request, and carries information indicating user access in Msg3 corresponding to the RRC connection request.

Specifically, the UE sends an RRC Connection Request (RRCConnection Request) message on the SRB0 through the UL-CCCH channel, and the message triggers the low-level entities of the UE to perform a contention-based random access procedure. The RRC connection request message corresponds to Msg3 in the lower layer random access procedure. Msg3 is transmitted according to the uplink resource allocated to it by the uplink authorization in the random access response that the UE correctly receives Msg2, and Msg3 will carry information indicating user access. The user access information includes an identifier that the user needs to access the trunking group call service.

Use the reserved bit of the information element in the RRC connection request message in Msg3 and/or the reserved value of the establishment cause to carry the user access information. The establishment cause refers to the EstablishmentCause in the RRC Connection Request information element. User access information can also be indicated by utilizing the emergency event "emergency" in the existing established reasons. According to the user access information, it can be judged whether the user wants to access the trunking group call service.

Step 302, eNB receives Msg3, and determines UE access to trunking group call service according to the user access information indicated; eNB allocates uplink resource for UE after sending RRC connection establishment message to UE.

After receiving the Msg3 sent by the trunking UE, the eNode B judges whether the user wants to access the trunking group call service according to the user access information carried in the received Msg3. If the user needs to access the trunking group call service, eNode B will send an uplink authorization to allocate uplink resources for the UE after sending Msg4 (including the RRC connection establishment message at this time), which is used for the UE to send the RRC connection establishment complete message.

The eNB first sends an RRC connection establishment request to the UE, and allocates uplink resources for the UE after an interval T, T≥T1+T2+T3, T1 is the time for the UE to resolve the RRC connection establishment request, and T2 is the time for the UE to configure the signaling radio bearer SRB1 , T3 is the time for assembling the RRC connection establishment complete message. Wherein, T1, T2, and T3 depend on hardware implementation, and are not limited in the present invention.

Specifically, after the eNB receives the Msg3 sent by the UE, the eNode B performs the following operations, see Figure 4:

401. The eNB obtains the indicated user access information according to the indicated user access information carried in Msg3.

402. The eNodeB judges whether the UE performs an RRC connection establishment process because of accessing the trunking group call service according to the access information of the indicated user. If yes, go to 403; otherwise, go to 404.

403. The eNB replies an RRC Connection Setup (RRC ConnectionSetup) message on SRB0 through the DL-DCCH. The RRC connection request message corresponds to Msg4 in the low-level random access process, which carries complete configuration information of SRB1, including configuration parameters of various entities such as PHY/MAC/RLC/PDCP. After eNode B sends Msg4, it sends the uplink authorization of the UE through PDCCH.

404. The eNB executes subsequent processing procedures according to the requirements of the standard LTE protocol.

Step 103, the cluster UE configures according to the RRC connection establishment message, and transmits an RRC connection establishment complete message according to the uplink resource.

Specifically, after receiving the Msg4 sent by the eNode B, the cluster UE will perform configuration according to the RRC connection establishment message in Msg4. At the same time, the UE has been monitoring the PDCCH and receiving the uplink grant belonging to the UE. After SRB1 is configured, UE sends an RRC Connection Setup Complete (RRC Connection Setup Complete) message on SRB1 through the UL-DCCH channel, which carries the initial NAS message in the uplink direction.

Three SRBs are defined in the LTE system, namely SRB0, SRB1 and SRB2. SRB1 is used to carry RRC messages on the DCCH, and before SRB2 is established, SRB1 may also be used to carry NAS messages. The SRB2 is used to bear the NAS message on the DCCH. The priority of the SRB2 is lower than that of the SRB1. The network must establish and use the SRB2 after the security is activated. Therefore, the cluster UE configures SRB1 according to the RRC connection establishment message.

The RRC connection establishment complete message is transmitted on the uplink resource allocated for the UE by the uplink grant. In this way, the cluster UE can send an RRC connection establishment completion message on the uplink resource allocated to it in advance without sending a scheduling request, thereby speeding up the establishment of the RRC connection.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (9)

1. A method for establishing a radio resource control protocol connection, characterized in that the method comprises: The cluster user UE sends a radio resource control protocol RRC connection request, and carries information indicating user access in a message Msg3 corresponding to the RRC connection request; The base station eNB receives the Msg3, and determines that the UE accesses the trunking group call service according to the indicated user access information; After the eNB sends an RRC connection establishment message to the UE, it allocates uplink resources for the UE; The cluster UE is configured according to the RRC connection establishment message, and transmits the RRC connection establishment complete message according to the uplink resource. 2 . The method for establishing a radio resource control protocol connection according to claim 1 , wherein said carrying information indicating user access includes carrying information indicating user access through a reserved bit of an information element of an RRC connection request. 3 . 3 . The method for establishing a radio resource control protocol connection according to claim 1 , wherein the carrying the user access indication information comprises carrying the user access information through a reserved value of the establishment cause. 4 . 4 . The method for establishing a radio resource control protocol connection according to claim 1 , wherein said carrying information indicating user access includes indicating user access information through emergency in the establishment reason. 5 . 5 . The method for establishing a radio resource control protocol connection according to claim 1 , wherein the allocating uplink resources for the UE comprises: allocating uplink resources for the UE by sending an uplink grant. 6. The method for establishing a radio resource control protocol connection according to claim 5, wherein said allocating uplink resources for the UE by sending an uplink grant comprises: allocating uplink resources for the UE by sending an uplink grant on a Physical Downlink Control Channel (PDCCH) . 7. The method for establishing a radio resource control protocol connection according to claim 1, wherein after the eNB sends an RRC connection establishment request message to the UE, allocating uplink resources for the UE comprises: the eNB first sends an RRC connection establishment request to the UE , allocate uplink resources to the UE after an interval T, T≥T1+T2+T3, T1 is the time for the UE to resolve the RRC connection establishment request, T2 is the time for the UE to configure the signaling radio bearer SRB1, and T3 is the time for assembling the RRC connection establishment completion message time. 8. The method for establishing a radio resource control protocol connection according to claim 1, wherein the configuration of the cluster UE according to the RRC connection establishment message comprises: the cluster UE monitors the PDCCH, and configures according to the RRC connection establishment message. 9 . The method for establishing a radio resource control protocol connection according to claim 1 , wherein the configuring the cluster UE according to the RRC connection establishment message comprises: configuring the cluster UE to configure SRB1 according to the RRC connection establishment message.

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