CN101047881A - Method and system for providing multicast bear - Google Patents

Abstract

The invention discloses a method for providing multicast bearer. A logical channel for transmitting multicast data is established between the network side and the UE side, and default multicast radio bearer parameters are set on the network side and the UE side. When When the UE requests the multicast streaming media service, the network side sends the RRC state transition command carrying the RAB identifier to the UE requesting the multicast streaming media service; after receiving the command, the UE side converts its own state to the common channel state, and according to The set default multicast radio bearer parameters establish a multicast radio bearer; the network side bears the multicast data on the established logical channel, and maps it to the common channel for transmission to the UE side; the UE side receives the bearer from the common channel on the Multicast data for the established logical channel. The invention also discloses a system for providing multicast bearer. According to the method and system disclosed in the invention, the channel mapping structure of the existing unicast streaming media service is slightly modified to realize the multicast streaming media service.

Description

A method and system for providing multicast bearer

technical field

The present invention relates to multicast technology, in particular to a method and system for providing multicast bearer.

Background technique

The radio link control (RLC) protocol implements data transmission modes on the air interface into three working modes: transparent mode (TM), unacknowledged mode (UM) and acknowledged mode (AM). In transparent mode and unacknowledged mode, there is a sending entity and a receiving entity, and in acknowledged mode there is only one entity combining sending and receiving. In the transparent mode, the RLC sending entity does not perform any processing on the upper layer data, and directly transmits it to the RLC receiving entity through a logical channel. In the non-confirmation mode, the RLC sending entity receives the upper layer data, segments and concatenates the data into several data blocks, adds a continuous sequence number to each data block, and transmits it to the RLC receiving entity through a logical channel; RLC The receiving entity receives the data blocks from the logical channel, de-segments and concatenates the received data blocks, restores the upper layer data, and submits them to the upper layer. The receiving entity can also check whether the sequence numbers of the received data blocks are continuous or not , to detect whether data is lost during transmission. In acknowledgment mode, in addition to realizing the functions of the above-mentioned non-acknowledgment mode, the RLC receiving entity also indicates to the RLC sending entity through the reverse channel which data blocks corresponding to the sequence numbers have not been received correctly, and requires the RLC sending entity to resend the corresponding sequence Number of data blocks to ensure reliable data transmission.

In the Radio Resource Control (RRC) protocol, an RRC entity controls user equipment (UE) transitions between dedicated channel states and common channel states. Figure 1 is a schematic diagram of RRC state transition, as shown in Figure 1, the RRC entity on the network side sends an RRC state transition command message to the RRC entity on the UE side, indicating the target state that the UE needs to transfer in the message, and the RRC entity on the UE side receives After the message, transfer to the corresponding target state, and return an RRC state completion response to the RRC entity on the network side.

The common channel acts as a random access channel (RACH) on the uplink and forward access channel (FACH) on the downlink. When the UE is in the common channel state, multiple UEs share a common channel. The network side assigns different cell radio network temporary identifiers (C-RNTI) to each UE, so that when each UE's data block is transmitted on a FACH channel, the network example adds the UE's C-RNTI to the header of each data block. RNTI, after the UE receives all the data blocks on the common channel, it uses the C-RNTI in the data blocks to distinguish whether each data block is sent to the UE.

Figure 2 is a schematic diagram of the channel mapping relationship at the initiation stage of the unicast streaming media service. Figure 2 includes the channel mapping relationship when UE A and UE B initiate the unicast service, as shown in A and B in Figure 2, respectively. Figure 3 is a schematic diagram of the channel mapping relationship in the receiving stage of the unicast streaming media service. Figure 3 includes the channel mapping relationship when UE A and UE B receive the unicast service, as shown in A and B in Figure 3, respectively.

The channel mapping structure shown in Figure 2 and Figure 3 includes: the network side and the UE side, the network side and the UE side respectively include a service layer and a transport layer, wherein the service layer includes a streaming media control plane, and the transport layer includes an RRC entity, an RLC entity And the logical channel, including the UE's dedicated channel between the network side and the UE side. In Fig. 3, the service layer further includes a streaming media user plane.

There is a corresponding relationship between the network service access point of the service layer and the radio access bearer of the transport layer. The streaming media control plane entity and the streaming media user plane entity use the same network service access point, and transmit unicast data on the same radio bearer. The streaming media control plane entity performs bidirectional data transmission, and the streaming media user plane entity performs downlink unidirectional data transmission. The RLC entity provides the radio bearer function. The unicast data is transmitted on the logical channel through the RLC entity, and different logical channels can be carried on the dedicated channel. The header of the data block transmitted on the dedicated channel of the UE includes a logical channel identifier, and the logical channel identifier is used to distinguish different logical channels, so that multiple logical channels can be multiplexed on one dedicated channel. The definition of the logical channel identifier is shown in Table 1. There are four bits in total, and the values are 0 to 15, among which, 0 to 14 are used to indicate logical channel 1 to logical channel 15, and 15 is reserved and not used.

Logical Channel ID express 0000 Logical channel 1 0001 Logical channel 2 ... ... 1110 Logical channel 15 1111 reserve

Table 1

In FIG. 2 and FIG. 3 , logical channel 1 is used to transmit RRC messages, and logical channel 2 is used to transmit streaming media service data.

As shown in Figure 2 and Figure 3, UE A and UE B have their own dedicated channels. When the UE is in the dedicated channel state, use the dedicated channel to distinguish different channels. When the UE is in the public channel state, use C in the business data transmitted on the public channel. -RNTI distinguishes between different channels.

With the continuous development of communication services, unicast services and multicast services coexist, so it is hoped that the multicast bearer can be realized without changing the above-mentioned channel mapping relationship when implementing unicast transmission.

In the prior art, without changing the above-mentioned channel mapping relationship when implementing unicast transmission, when implementing multicast streaming media services, the channel mapping relationship at the initiation stage of multicast streaming media services is the same as that shown in Figure 2 relationship, while the channel mapping relationship in the receiving phase of the multicast streaming media service is shown in Figure 4.

Figure 4 includes UE A and UE B. Each UE has its own dedicated channel, and the UE is in the public channel state. When the UE receives multicast data, the two-way logical channel uses UM mode, and the multicast data sent by the network side passes through the downlink logical channel transmitted to the UE side. As shown in Figure 4, on the basis of unicast bearer, multicast bearer has the following characteristics:

(1) The downlink logical channel is used to bear downlink multicast data, and is no longer used to bear downlink unicast data. The reason why downlink unicast data and downlink multicast data cannot be transmitted through the same downlink logical channel is that downlink multicast data is shared by all multicast UEs in a cell, and has its own characteristics of segmented data cascading and adding sequence numbers. If the downlink unicast data of a single UE is added, the desegmentation and concatenation function of the RLC receiving entity will be disturbed, resulting in that the downlink unicast data and multicast data of the UE cannot be received normally. Therefore, when multicast transmission is implemented, downlink unicast data cannot be transmitted to the UE side through the downlink logical channel, that is, the downlink unicast channel is interrupted.

(2) The downlink multicast data is transmitted in the unacknowledged mode of RLC, that is, the UM RLC sending entity on the network side carries the downlink multicast data in a logical channel and sends it to the UM RLC receiving entity on the UE side. Because, if the downlink multicast data adopts RLC acknowledgment mode, after receiving the downlink multicast data, the RLC entities on the UE side will feed back the reception status of the multicast data to the RLC entity on the network side, resulting in the processing of the RLC entity on the network side It's complex and prone to problems. However, if the transmission of the downlink multicast data adopts the unacknowledged mode of the RLC, the transmission of the uplink unicast data also adopts the unacknowledged mode, thus causing the transmission of the uplink unicast data to be unreliable.

(3) When the multicast transmission needs to be realized, the multicast data does not need to be encrypted on the air interface, and the UE side does not need to start the encryption function. Because, under normal circumstances, during unicast transmission, unicast data is generally encrypted on the air interface, and each UE has its own specific encryption key, and the encryption process in the existing protocol cannot be stopped once a connection process is started. However, the downlink multicast data needs to be sent to multiple UEs, so it cannot be encrypted on the air interface, and the UE that needs to realize the multicast service cannot start the encryption function when the connection is established.

To sum up, in the prior art solution, the implementation of multicast bearing in the existing channel mapping structure for bearing unicast has the following disadvantages, which are summarized as follows: when implementing multicast bearing, the downlink logical channel is only used for Transmission of downlink multicast data, so the transmission channel of downlink unicast data is interrupted during the transmission of multicast data; when implementing multicast bearer, the unacknowledged mode of RLC is used, so the uplink unicast data cannot be transmitted reliably; When the multicast bearer is used, since the downlink multicast data is not encrypted on the air interface, the UE that wants to start the multicast service cannot start the encryption function when the connection is established.

Contents of the invention

In view of this, the main purpose of the present invention is to provide a method for providing multicast bearer, which requires less modification to the channel mapping structure of the existing unicast streaming media service, and realizes the multicast streaming media service.

Another main purpose of the present invention is to provide a system for providing multicast bearer, which can realize the multicast streaming service with less modification to the channel mapping structure of the existing unicast streaming media service.

In order to achieve the above object, the present invention provides a method for providing multicast bearer, which establishes a logical channel for transmitting multicast data between the network instance and the user equipment UE side, and sets a default group Broadcasting radio bearer parameters, the method includes:

When the UE requests the multicast streaming media service, the network side sends a radio resource control RRC state transition command to the UE requesting the multicast streaming media service, and the command carries the radio access bearer RAB identifier; the UE side receives the RRC state transition command After that, convert its own state to a common channel state, and establish a multicast radio bearer according to the set default multicast radio bearer parameters;

The network side carries the multicast data on the established logical channel, and maps it to the common channel for transmission to the UE side; the UE side receives the multicast data carried on the established logical channel from the common channel.

The RAB corresponding to the RAB identifier is the RAB used when the UE requests the multicast streaming media service.

The logical channel established between the network side and the UE side is: a logical channel whose logical channel identifier is 15;

The network side further assigns a group radio network temporary identifier G-RNTI for each multicast streaming media service;

The network side further judges whether the cell radio network temporary identifier C-RNTI of the UE belongs to the multicast group indicated by the G-RNTI according to the corresponding G-RNTI of the multicast streaming media service requested by the UE, if If not, re-allocate the C-RNTI belonging to the multicast group to the UE;

When the network side maps the logical channel carrying multicast data on the public channel, the media access control MAC protocol data unit PDU carries the G-RNTI corresponding to the multicast streaming media service requested by the UE;

When the UE side receives the multicast data carried on the logical channel from the common channel, it obtains the G-RNTI in the MAC PDU, and judges whether it belongs to the same multicast group as its own C-RNTI, and if so, receives the corresponding multicast data, and forward the multicast data to the upper-layer application through the network service access point NSAPI corresponding to the RAB identifier carried in the RRC state transition command, otherwise discard the data.

The judging whether the C-RNTI of the UE belongs to the multicast group represented by the G-RNTI is as follows: obtaining the group identifier Group-Id from the C-RNTI and the G-RNTI respectively, and comparing the obtained C-RNTI and the G-RNTI Whether the Group-Ids are the same.

The logical channel established between the network side and the UE side is a multimedia broadcast multicast service channel MTCH;

The RRC state transition command sent by the network side to the UE further carries a multimedia broadcast multicast service identifier MBMS-Id, and the value of the MBMS-Id is the MBMS-Id of the multicast streaming media service requested by the UE;

The network side sets the MBMS-Id of the MTCH carrying multicast data as the MBMS-Id of the multicast streaming media service requested by the UE; the UE side obtains the MBMS-Id from the MTCH carrying multicast data, and judges whether it is compatible with the RRC Whether the MBMS-Id carried in the state transition command is the same, if so, receive the corresponding multicast streaming media service data, and forward the multicast data to the upper layer through the NSAPI corresponding to the RAB identifier carried in the RRC state transition command applied, otherwise the data is discarded.

The default multicast radio bearer parameter of the setting is: setting the multicast data transmission mode as UM mode;

The network side sets the UM RLC entity, and the UM RLC entity carries the multicast data on the established logical channel, and maps it to the common channel for transmission to the UE side;

The UE side sets a UM RLC entity, and the UM RLC entity receives the multicast data carried on the established logical channel from the common channel.

The default multicast radio bearer parameter for setting is: setting does not enable the encryption function;

When the network side sends multicast data, the multicast data is not encrypted on the air interface;

When the UE side receives the multicast data, it does not decrypt the multicast data.

After receiving the RRC state transition command, the UE side further includes: returning an RRC state transition completion response to the network side.

The method further includes: maintaining the dedicated logical channel used when the UE requests the multicast streaming media service.

In order to achieve the above second objective, the present invention provides a system for providing multicast bearer, including a network side and a UE side, and a logical channel for carrying unicast data between the network side and the UE side, characterized in that, The system further includes: a logical channel between the network side and the UE side for carrying multicast data.

The network side and the UE side respectively include an RRC entity and an RLC entity;

The network side further includes: a UM RLC sending entity for sending multicast data;

The UE side further includes: a UM RLC receiving entity for receiving multicast data.

The RRC entity on the network side is used to allocate the C-RNTI belonging to the G-RNTI multicast group to the UE according to the G-RNTI allocated by the network side corresponding to the multicast streaming media service identifier, and is used to send the C-RNTI carrying the radio access to the UE side. Enter the RRC state transition command of the bearer identifier;

The RRC entity on the UE side is used to convert its own state to a common channel state according to the RRC state transition command on the network side, and establish a multicast bearer according to the radio access bearer identifier, and receive multicast streaming media data.

In the method and system provided by the present invention, on the basis of the existing channel mapping structure for unicast bearer, a logical channel for carrying multicast data is added, and multicast bearer is realized by setting multicast wireless bearer parameters in advance. The following beneficial effects:

1) The transmission of uplink/downlink unicast data can still be realized through the existing channel mapping structure of unicast bearer;

2) Encryption functions can be enabled and disabled for unicast and multicast services respectively;

3) The channel mapping structure of the existing unicast bearer can use the unicast data transmission in the confirmation mode, so the transmission reliability of the uplink unicast data can be guaranteed;

4) The existing unicast bearer channel mapping structure can also use unacknowledged mode and transparent mode unicast data transmission, and can be realized on the basis of unacknowledged mode and transparent mode unicast bearer channel mapping structure For multicast bearer, there is little or no change to the existing channel mapping structure for unicast bearer.

Description of drawings

FIG. 1 is a schematic diagram of RRC state transition in the prior art;

FIG. 2 is a schematic diagram of the channel mapping relationship in the initiation stage of the unicast streaming media service in the prior art;

FIG. 3 is a schematic diagram of the channel mapping relationship in the receiving phase of the unicast streaming media service in the prior art;

FIG. 4 is a schematic diagram of channel mapping in the receiving phase of a multicast streaming media service in the prior art;

FIG. 5 is a schematic diagram of the channel mapping relationship in the receiving phase of the multicast streaming media service using the dedicated logical channel whose logical channel identifier is 15 in the first embodiment of the present invention;

FIG. 6 is a schematic diagram of the channel mapping relationship in the receiving stage of the multicast streaming media service using MTCH in the second embodiment of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, specific examples are given below to further describe the present invention in detail.

The general idea of providing multicast bearer in the present invention is: on the basis of the existing unicast bearer, add a logical channel for transmitting multicast data, and set default parameters for multicast wireless bearer parameters; when the network side determines After the UE side requests the multicast service, it initiates the RRC state transfer process to the UE side, and then sends the multicast data bearer on the added logical channel to the UE side according to the set default parameters of the multicast radio bearer; Set default parameters of the multicast radio bearer to receive the multicast data.

Embodiment 1: A multicast bearer solution using a dedicated logical channel whose logical channel ID is 15

Figure 5 is a schematic diagram of the channel mapping relationship in the receiving stage of the multicast streaming media service using the dedicated logical channel whose logical channel identifier is 15. As shown in Figure 5, the channel mapping relationship includes the receiving stage of the unicast streaming media service shown in Figure 3 In addition to the channel mapping structure, it further includes: a logical channel with a logical channel ID of 15 for transmitting multicast data, an RLC entity that provides multicast radio bearer, and a multicast channel that carries the logical channel.

In order to realize the multicast streaming media service, on the basis of the existing unicast bearer system, a multicast channel is added between the network side and the UE side, and the added multicast channel is used to bear the logical channel for transmitting multicast data. In addition, in order to distinguish the multicast channel carrying different multicast data, the group radio network temporary identifier (G-RNTI) is set for the UE identification extension in the MAC protocol data unit (PDU) transmitted in the multicast channel. The G-RNTI is the network side The parameters assigned to each different service for distinguishing different multicast services, that is, the G-RNTI corresponds one-to-one with the identifier of the multicast streaming media service. Wherein, the configured G-RNTI structure includes a group identifier (Group-Id) for distinguishing different multicast groups.

The logical channel identifier of the logical channel used to transmit multicast data is configured as the reserved logical channel identifier 15 .

The multicast radio bearer parameters adopt preset default parameters, and the preset default parameters refer to: the multicast data transmission mode adopts UM mode, that is, the RLC entity adopts UM mode; the air interface encryption function is not activated during multicast data transmission , that is, the network side does not encrypt the multicast data sent on the air interface, and the UE side does not decrypt the received multicast data.

The setting of the multicast radio bearer corresponds to the radio access bearer (RAB), which is the network service access point (NSAPI) of the control plane for transmitting streaming media.

In the multicast bearer system shown in Figure 5, the method for realizing multicast bearer is as follows:

Step 101: After the service initiation phase is completed, the streaming media control plane entity of the service layer on the network side determines that the UE needs to initiate a multicast streaming media service, and notifies the RRC entity of the transport layer on the network side, and the notification message includes the multicast streaming media service identifier.

Step 102: The RRC entity of the transport layer on the network side judges whether the C-RNTI of the UE belongs to the multicast group represented by the G-RNTI according to the G-RNTI corresponding to the multicast streaming service identifier, if the C-RNTI of the UE does not If the UE belongs to the multicast group indicated by the G-RNTI, a new C-RNTI belonging to the multicast group is allocated to the UE. After the RRC entity allocates a new C-RNTI to the UE, the network side can send the C-RNTI to the UE side through the signaling interaction process between the network side and the UE side, and the UE updates its own C-RNTI to be assigned by the network side For example, when the network side sends the RRC state transition command to the UE side, the C-RNTI can be carried to the UE. Wherein, the allocated C-RNTI structure includes a group identifier (Group-Id) for distinguishing different multicast groups.

The method for judging whether the C-RNTI belongs to the multicast group represented by the G-RNTI is: since both the C-RNTI and the G-RNTI contain the Group-Id, the Group-Id is respectively obtained from the C-RNTI and the G-RNTI, And judge whether the two Group-Ids are the same, if they are the same, it is considered that the C-RNTI belongs to the multicast group indicated by the G-RNTI; otherwise, it is considered that the C-RNTI does not belong to the multicast group indicated by the G-RNTI.

Step 103: The RNC obtains the radio access bearer identifier, and the radio access bearer identifier corresponds to the network service access point identifier of the transmission streaming media control plane, therefore, by obtaining the network service access point identifier of the streaming media control plane The radio access bearer identifier; or, since the radio access bearer is the radio access bearer when the UE requests the multicast service, the radio access bearer identifier may be acquired by acquiring the context of the UE.

Step 104: The RRC entity of the transport layer on the network side sends an RRC state transition command to the RRC entity of the transport layer on the UE side, and the RRC state transition command indicates that the target state of the transfer is a common channel state, and the message includes the extended information element "and multicast The radio access bearer identification corresponding to the radio bearer", whose value is the identification of the radio access bearer currently transmitting streaming media control plane data, that is, the RAB identification obtained in step 103; the "multicast radio bearer radio access The bearer identifier' IE indicates that a multicast radio bearer is to be established.

Step 105: After receiving the RRC state transition command, the RRC entity of the transport layer on the UE side transfers its own state to the common channel state, establishes a multicast radio bearer according to the "radio access bearer identifier of the multicast radio bearer", and Return an RRC state transition completion response to the RRC entity on the network side.

The process of establishing a multicast radio bearer is the process of configuring the multicast radio bearer parameters. When configuring the multicast radio bearer parameters, you need to configure the RLC entity in UM mode according to the preset default parameters, and configure it not to start when transmitting multicast data. encryption function.

At this time, the UE can receive the multicast data sent by the network side.

If the UE is the first UE to receive the multicast data, the streaming user at the service layer on the network side sends the multicast data to the streaming user plane at the service layer on the UE side, and the multicast data is carried by the multicast radio The parameters are carried by the UM RLC entity on the network side on the logical channel with the logical channel ID 15, and are mapped to the common channel and transmitted to the UE side. The common channel is the common channel that the UE starts to monitor after receiving the RRC state transition command. When the network side transmits multicast data on a common channel, set the G-RNTI used to represent the multicast streaming service identifier in the UE ID in the PDU of the MAC to distinguish between groups that carry different multicast streaming services. broadcast channel, and according to the pre-setting of the multicast radio bearer parameters, the multicast data is not encrypted on the air interface.

If the UE is not the first UE to receive the multicast data, the network side is sending the multicast data, so the UE can immediately receive the multicast data.

The process of receiving multicast data by the streaming user plane of the service layer on the UE side is as follows: the streaming user plane of the service layer on the UE side extracts the G-RNTI from the multicast streaming service data carried in the common channel, and judges the Whether the C-RNTI has the same Group-Id, if yes, receive the corresponding multicast streaming media service data, and forward the multicast data to the upper layer through the NSAPI corresponding to the RAB identifier carried in the RRC state transition command applied, otherwise the data is discarded.

As described in Embodiment 1, when the logical channel with the logical channel identifier 15 is used as the logical channel of the multicast radio bearer, after the UE identifies its own data packet through the identifiers such as C-RNTI or G-RNTI, it will also use the logical channel identifier Differentiate logical channels. If a UE currently has multiple logical channels, it may use logical channels with logical channel IDs 1 to 14 for its own dedicated data, but the multicast logical channel must be a logical channel with logical channel ID 15, so the UE receives When there are multiple service data, there will be no conflict; if the multicast logical channel uses the logical channel with the logical channel ID of 14, assuming that the user has a unicast logical channel that is also the logical channel with the logical channel ID of 14, then the two The data may be considered as the data of the same logical channel, and there will be problems when the UE side receives the data. In order to ensure that the logical channel identifier that may be used by unicast will not be used, the present invention uses the logical channel whose logical channel identifier is 15, because the logical channel identifier 15 is reserved in the prior art.

Embodiment 2: Multicast bearer solution using MTCH

Fig. 6 is a schematic diagram of the channel mapping relationship in the receiving stage of the multicast streaming media service using MTCH. It includes: MTCH for transmitting multicast data, an RLC entity providing multicast radio bearer, and a common channel carrying logical channels, and the common channel may be FACH.

The logical channel used to carry multicast data adopts MTCH. When MTCH is carried on the downlink common channel, the value of the TCTF field contained in the data block header is 0110, indicating that the service currently carried is MBMS service, and the MBMS- Id is 4 bits, its value is 0 to 14, 15 is reserved, the value of MBMS-Id can be configured arbitrarily, and is used to distinguish multiple MTCHs mapped to the same downlink common channel.

The channel structure of MTCH is shown in Table 2.

Table 2

The multicast radio bearer parameters adopt preset default parameters, and the preset default parameters refer to: the multicast data transmission mode adopts UM mode, that is, the RLC entity adopts UM mode; the air interface encryption function is not activated during multicast data transmission , that is, the network side does not encrypt the multicast data sent on the air interface, and the UE side does not decrypt the received multicast data.

The setting of the multicast radio bearer corresponds to the network service access point of the transmission stream media control plane, that is, the radio access bearer.

In the multicast bearer system shown in Figure 6, the method for realizing multicast bearer is as follows:

Step 201: After the service initiation phase is completed, the streaming media control plane entity of the service layer on the network side determines that the UE needs to initiate a multicast streaming media service, and notifies the RRC entity of the transport layer on the network side, and the notification message includes the multicast streaming media service identifier.

Step 202: The RNC obtains the radio access bearer identifier, and the radio access bearer identifier corresponds to the network service access point identifier of the transmission streaming media control plane, therefore, by obtaining the network service access point identifier of the streaming media control plane The radio access bearer identifier; or, since the radio access bearer is the radio access bearer when the UE requests the multicast service, the radio access bearer identifier may be acquired by acquiring the context of the UE.

Step 203: The RRC entity of the transport layer on the network side sends an RRC state transition command to the RRC entity of the transport layer on the UE side, and the RRC state transition command indicates that the target state of the transfer is a common channel state, and the message contains the extended information element "and multicast "Radio Access Bearer Identifier Corresponding to Radio Bearer" and "MBMS-Id", where the value of "Radio Access Bearer Identifier Corresponding to Multicast Radio Bearer" is the identifier of the radio access bearer that currently transmits streaming media control plane data , that is, the RAB identifier obtained in step 202, the value of "MBMS-Id" is the MBMS-Id of the streaming multicast media service that the UE needs to read, and the extended information element indicates that a multicast radio bearer is to be established.

Step 204: After receiving the RRC state transition command, the RRC entity of the transport layer on the UE side transfers its own state to the common channel state, and according to the "radio access bearer identity of the multicast radio bearer" and "MBMS-Id" Establish a multicast radio bearer, and return an RRC state transition completion response to the RRC entity on the network side.

The process of establishing a multicast radio bearer is the process of configuring the multicast radio bearer parameters. When configuring the multicast radio bearer parameters, you need to configure the RLC entity in UM mode according to the preset default parameters, and configure it not to start when transmitting multicast data. encryption function.

At this time, the UE can receive the multicast data sent by the network side.

If the UE is the first UE to receive the multicast data, the streaming user at the service layer on the network side sends the multicast data to the streaming user plane at the service layer on the UE side, and the multicast data is carried by the multicast radio bearer The parameters are carried on the MTCH by the UM RLC entity on the network side, and are mapped to the common channel for transmission to the UE side. When the network side sends multicast data, the MBMS-Id of the multicast streaming media service that the UE needs to read is set in the MBMS-Id of the MTCH, and according to the pre-setting of the multicast radio bearer parameters, the multicast data is not performed on the air interface. encryption.

If the UE is not the first UE to receive the multicast data, the network side is sending the multicast data, so the UE can immediately receive the multicast data.

The process for the streaming user plane of the service layer on the UE side to start receiving multicast data is: the streaming user plane of the service layer on the UE side extracts the MBMS-Id from the multicast streaming service data carried in the MTCH on the common channel, And judge whether it is the same as the MBMS-Id carried in the RRC state transition command, if yes, then receive the corresponding multicast streaming media service data, and pass the multicast data through the corresponding RAB identifier carried in the RRC state transition command NSAPI forwards to the upper layer application, otherwise the data is discarded.

In Embodiment 1 and Embodiment 2 described above, no change is made to the channel mapping structure in the receiving phase of the existing unicast streaming media service shown in FIG. The data can be transmitted in TM, UM, and AM modes respectively, and the encryption function can still be activated for the transmission of unicast data.

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

Claims (11)

1. A method for providing multicast bearer, characterized in that a logical channel for transmitting multicast data is established between the network side and the user equipment UE side, and a default multicast wireless channel is set between the network side and the UE side Bearer parameters, the method includes: When the UE requests the multicast streaming media service, the network side sends a radio resource control RRC state transition command to the UE requesting the multicast streaming media service, and the command carries the radio access bearer RAB identifier; the UE side receives the RRC state transition command After that, convert its own state to a common channel state, and establish a multicast radio bearer according to the set default multicast radio bearer parameters; The network side carries the multicast data on the established logical channel, and maps it to the common channel for transmission to the UE side; the UE side receives the multicast data carried on the established logical channel from the common channel. 2. The method according to claim 1, wherein the RAB corresponding to the RAB identifier is the RAB used when the UE requests a multicast streaming media service. 3. The method of claim 1, wherein: The logical channel established between the network side and the UE side is: a logical channel whose logical channel identifier is 15; The network side further assigns a group radio network temporary identifier G-RNTI for each multicast streaming media service; The network side further judges whether the cell radio network temporary identifier C-RNTI of the UE belongs to the multicast group indicated by the G-RNTI according to the corresponding G-RNTI of the multicast streaming media service requested by the UE, if If not, re-allocate the C-RNTI belonging to the multicast group to the UE; When the network side maps the logical channel carrying multicast data on the public channel, the media access control MAC protocol data unit PDU carries the G-RNTI corresponding to the multicast streaming media service requested by the UE; When the UE side receives the multicast data carried on the logical channel from the common channel, it obtains the G-RNTI in the MAC PDU, and judges whether it belongs to the same multicast group as its own C-RNTI, and if so, receives the corresponding group Broadcast data, and forward the multicast data to the upper-layer application through the network service access point NSAPI corresponding to the RAB identifier carried in the RRC state transition command, otherwise discard the data. 4. The method according to claim 3, wherein the judging whether the C-RNTI of the UE belongs to the multicast group represented by the G-RNTI is: obtaining the group identifier Group from the C-RNTI and the G-RNTI respectively -Id, and compare whether the obtained C-RNTI is the same as the Group-Id in the G-RNTI. 5. The method of claim 1, wherein: The logical channel established between the network side and the UE side is a multimedia broadcast multicast service channel MTCH; The RRC state transition command sent by the network side to the UE further carries a multimedia broadcast multicast service identifier MBMS-Id, and the value of the MBMS-Id is the MBMS-Id of the multicast streaming media service requested by the UE; The network side sets the MBMS-Id of the MTCH carrying multicast data as the MBMS-Id of the multicast streaming media service requested by the UE; the UE side obtains the MBMS-Id from the MTCH carrying multicast data, and judges whether it is compatible with the RRC Whether the MBMS-Id carried in the state transition command is the same, if so, receive the corresponding multicast streaming media service data, and forward the multicast data to the upper layer through the NSAPI corresponding to the RAB identifier carried in the RRC state transition command applied, otherwise the data is discarded. 6. The method according to any one of claims 1 to 5, wherein the setting of the default multicast radio bearer parameters is: setting the multicast data transmission mode to UM mode; The network side sets the UM RLC entity, and the UM RLC entity carries the multicast data on the established logical channel, and maps it to the common channel for transmission to the UE side; The UE side sets a UM RLC entity, and the UM RLC entity receives the multicast data carried on the established logical channel from the common channel. 7. The method according to any one of claims 1 to 5, wherein the setting of the default multicast radio bearer parameters is: setting the encryption function not enabled; When the network side sends multicast data, the multicast data is not encrypted on the air interface; When the UE side receives the multicast data, it does not decrypt the multicast data. 8. The method according to any one of claims 1 to 5, characterized in that after the UE side receives the RRC state transition command, it further comprises: returning an RRC state transition completion response to the network side. 9. A method according to any one of claims 1 to 5, characterized in that, The method further includes: maintaining the dedicated logical channel used when the UE requests the multicast streaming media service. 10. A system for providing multicast bearer, including a logical channel between the network side and the UE side, and between the network side and the UE side for carrying unicast data, characterized in that the system further includes: the network side and the UE side A logical channel between two parties for carrying multicast data. 11. The system of claim 10, wherein: The network side and the UE side respectively include an RRC entity and an RLC entity; The network side further includes: a UM RLC sending entity for sending multicast data; The UE side further includes: a UM RLC receiving entity for receiving multicast data. The RRC entity on the network side is used to allocate the C-RNTI belonging to the G-RNTI multicast group to the UE according to the G-RNTI allocated by the network side corresponding to the multicast streaming media service identifier, and is used to send the C-RNTI carrying the radio access to the UE side. Enter the RRC state transition command of the bearer identifier; The RRC entity on the UE side is used to convert its own state to a common channel state according to the RRC state transition command on the network side, and establish a multicast bearer according to the radio access bearer identifier, and receive multicast streaming media data.

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