CN1716830A - Method for realizing multimedia broadcast and multi cast service by air interface - Google Patents

Abstract

The invention discloses a method for realizing multimedia broadcast and multicast services through an air interface. The method firstly sets an air interface user plane structure including RLC, MAC and PHY. Based on the air interface user plane structure, RNC transmits multimedia broadcast data When sending to the UE, first copy the multimedia broadcast data sent by the SGSN to all the RLCs corresponding to each cell contained in the multimedia broadcast multicast service area through the multimedia service data relay; the RLC processes the multimedia broadcast data and sends it through the CTCH To the MAC, the MAC processes the received multimedia broadcast data and sends it to the Node B, and the Node B sends the received multimedia broadcast data through the air interface; the UE receives the multimedia broadcast data sent by the Node B through the air interface. The invention solves the problem that the multimedia broadcast data cannot be broadcast through the existing logical channel at present. The solution provided by the invention realizes the broadcasting of multimedia broadcasting data through the existing logical channel.

Description

A method for realizing multimedia broadcast multicast service through air interface

technical field

The present invention relates to the technical field of multimedia broadcast multicast (MBMS) service, more precisely, relates to a method for realizing multimedia broadcast multicast service through an air interface.

Background technique

The broadcast services of the third generation mobile communication include Cell Broadcast Service (CBS) and MBMS. With the development of multimedia technology, more and more users pay attention to MBMS, which includes information such as video, audio, picture and text in business content.

These two broadcasting services require a single-point-to-multipoint service bearer between the Terrestrial Radio Access Network (UTRAN) and the User Equipment (UE) of the Universal Mobile Communications System, where the UTRAN includes a Radio Network Controller (RNC) and Base station (Node B). For the current CBS, the application layers of the CBS are respectively located in the Cell Broadcast Center (CBC) and the UE, and the cell broadcast service data needs to be transmitted through the Iu-BC interface and the air interface (Uu). Specifically, referring to Fig. 1, CBC and RNC in UTRAN communicate through the Service Area Broadcast Protocol (SABP) message, that is, the cell broadcast service data in the CBC is sent from the Iu-BC interface to the RNC through the SABP message, and the broadcast in the RNC The multicast control (BMC) obtains cell broadcast service data and related information from the received SABP message, assembles these information into a BMC message, and repeatedly broadcasts the BMC message on Uu through the common traffic channel (CTCH) at a certain period. Only when the BMC receives the SABP message from the CBC again, does it stop repeating the original BMC message and process the newly received SABP message.

In the protocol stack shown in Figure 1, there is no user plane dedicated to carrying cell broadcast service data between CBC and RNC, and the BMC needs to transmit cell broadcast service data through SABP messages. The real-time performance of this message communication mechanism is poor. It is only suitable for transmitting short messages, but not for services with high real-time requirements such as streaming services. In addition, the SABP message can only carry cell broadcast service data with a maximum length of 1230 bytes, which is not suitable for transmitting multimedia services with a large amount of information. In addition, the air interface user plane structure of the cell broadcast service includes the BMC entity for assembling and broadcasting the BMC message. Due to the limited length of the BMC message and the considerable delay introduced by mechanisms such as storage and retransmission in the BMC, it cannot meet the High real-time service requirements, therefore, the CBS user plane structure including the BMC entity cannot meet the rate and real-time requirements of the multimedia broadcast multicast service with streaming service characteristics. Therefore, the user plane structure and protocol stack for CBS are not suitable for broadcasting multimedia messages with streaming service characteristics such as video and audio.

In order to realize multimedia broadcasting, the industry has proposed a multimedia broadcasting user plane structure for sending multimedia messages. This structure is shown in Figure 2. The application layers of multimedia broadcasting and multicasting services are respectively distributed in the broadcasting and multicasting service center (BM-SC) And in UE, Gateway General Packet Radio Service (GPRS) Support Node (GGSN), Service GPRS Support Node (SGSN) and UTRAN are located between BM-SC and UE, and these entities complete the transparent forwarding of multimedia broadcast multicast service data. Wherein, the MBMS air interface user plane structure is determined by the MTCH protocol structure shown in FIG. 3 .

The MBMS protocol defines two logical channels for multimedia broadcast multicast services: MBMS Control Channel (MCCH) and MBMS Traffic Channel (MTCH). Among them, MCCH is used to carry MTCH configuration information and service-related control information, and MTCH is Used to carry broadcast service data. The configuration information of MCCH is carried by broadcast control channel (BCCH). The protocol structure of MTCH specifically includes sublayers such as packet data control protocol (PDCP), RLC, MAC, and PHY. Refer to FIG. 3 for the protocol structure.

The PDCP in Figure 3 is mainly used to complete the header compression/decompression function of the MBMS service. On the UTRAN side, the MBMS service of each MBMS cell group corresponds to a PDCP; on the UE side, each MBMS service corresponds to a PDCP entity. The PDCP at the UTRAN side also copies the processed PDCP protocol data unit to the RLC entities of all cells in the cell group. For RLC, on the UTRAN side, each MBMS service in each cell corresponds to one RLC entity; on the UE side, each MBMS service also corresponds to one RLC entity. For MAC, on the UTRAN side, each cell corresponds to a MAC entity; on the UE side, each UE corresponds to a MAC entity.

Based on the MTCH protocol structure shown in Figure 3, when broadcasting multimedia broadcast data through the air interface, that is, when the UTRAN broadcasts the multimedia broadcast data sent by the BM-SC via the GGSN and SGSN to the UE through the air interface, the multimedia data relay First, the multimedia broadcast data sent by the SGSN is forwarded to its own PDCP, and the PDCP performs header compression processing on the received data, and copies the processed data to the RLC entities of all cells in the cell group. After processing the data, entities such as RLC and MAC send the data to the physical layer (PHY) located in the Node B, and the Node B sends the data through the PHY. When the UE receives data, the PHY in the UE first receives the data sent by the Node B through the air interface, and then delivers it to the upper layer protocol entities such as MAC, RLC, and PDCP for processing, which corresponds to the header compression processing performed by PDCP in the RNC. The PDCP needs to decompress the received data.

As mentioned above, one function of setting PDCP in the MTCH protocol structure is to compress the IP header of the PDCP data packet, so as to reduce the length of the PDCP packet. Although this can save some transmission resources, it increases the complexity and processing delay of data processing. Moreover, this solution requires that the UE side also supports PDCP to decompress the received data packets, which increases the implementation complexity of the UE side.

In addition, since the MAC c/sh defined by the MAC protocol does not support MTCH, it is necessary to add MAC-m supporting MTCH on the basis of the original MAC c/sh. In this way, the protocol structure of MTCH includes PDCP and MAC-m at the same time, and this protocol structure is different from all existing logical channel structures, so it is impossible to use the existing logical channel to realize the function of MTCH. Both PDCP and MAC-m are introduced into the channel structure. In addition, MTCH configuration information needs to be configured through MCCH, so it is necessary to introduce MCCH into the existing Uu structure, and at the same time add MCCH configuration information to BCCH to realize multimedia broadcast multicast services. The existing Uu structure is greatly modified.

That is to say, the MTCH and MCCH defined by the MBMS protocol cannot be implemented based on the existing air interface structure, and the current MBMS protocol is not yet mature and relatively incomplete. Make more changes to the existing structure.

Contents of the invention

In view of this, the main purpose of the present invention is to provide a method for implementing multimedia broadcast multicast services through the air interface, so as to implement multimedia broadcasting through existing logical channels.

In order to achieve the above object, the technical solution of the present invention is realized in the following way: a method for realizing multimedia broadcast multicast service through the air interface, the multimedia broadcast data in the broadcast multicast service center BM-SC is supported successively by the gateway general packet radio service The node GGSN, the service general packet radio service support node SGSN and the radio network controller RNC are processed, and are sent to the user equipment UE by the RNC through the air interface. The method includes: setting radio link control RLC, medium access control MAC and physical Layer PHY air interface user plane structure;

Based on the air interface user plane structure, the RNC sending the multimedia broadcast data to the UE through the air interface includes the following steps:

a. The RNC copies the multimedia broadcast data sent by the SGSN to all RLCs corresponding to each cell contained in the multimedia broadcast multicast service area through the multimedia service data relay;

b. RLC processes the received multimedia broadcast data, and sends the processed multimedia broadcast data to MAC through CTCH, MAC processes the received multimedia broadcast data, and sends it to the base station Node B, and Node B passes the air interface Send the received multimedia broadcast data;

c. The UE receives the multimedia broadcast data sent by the Node B through the air interface.

The air interface user plane structure comprising RLC, MAC and PHY is set as follows: RLC, MAC and PHY are set on the UE side of the air interface user plane structure, RLC and MAC are set on the RNC side, and PHY is set on the Node B side.

In the step b, the MAC sends the processed multimedia broadcast data to the Node B as follows: the MAC sends the processed multimedia broadcast data to the PHY located at the Node B;

In step c, the UE receiving the broadcast data sent by the Node B is: the UE receives the broadcast data sent by the Node B through its own PHY.

After the step c, it further includes: the UE processes the received multimedia broadcast data through MAC and RLC in sequence.

The method may further include: setting the interface between the GGSN and the SGSN as a General Packet Radio Service Tunneling Protocol (GTP) tunnel bearer.

The method may further include: setting the interface between the SGSN and the RNC as a GTP tunnel bearer.

The solution of the present invention provides a CTCH-based multimedia broadcast air interface user plane structure, so that while realizing the multimedia broadcast multicast service, it is not necessary to define a new logical channel, reducing the cost of realizing the multimedia broadcast multicast service in the existing RNC-UE system Difficulty, and reduce the modification of the existing RNC-UE system structure to realize the multimedia broadcast multicast service.

In addition, there is no BMC entity in the air interface user plane structure of the existing cell broadcast service in the air interface user plane structure of the multimedia broadcast multicast service provided by the present invention, so it will not be limited by the length of the BMC message and the BMC scheduling function, and thus will not affect The rate and real-time performance of multimedia broadcast multicast services characterized by streaming services.

The present invention sets the multimedia service data relay for duplicating the multimedia broadcast data to all RLCs corresponding to each sub-district included in the MBMS service area, so that the duplication of the broadcast data can be realized without adding PDCP.

Description of drawings

FIG. 1 is a schematic diagram of an existing cell broadcast service protocol stack;

FIG. 2 is a schematic diagram of a multimedia broadcast user plane structure specified in the existing MBMS protocol;

FIG. 3 is a schematic structural diagram of the multimedia broadcast air interface user plane protocol specified in the existing MBMS protocol;

FIG. 4 is a schematic structural diagram of the multimedia broadcast air interface user plane protocol provided by the present invention;

FIG. 5 is a schematic structural diagram of a multimedia broadcast user plane provided by the present invention;

FIG. 6 is a flow chart of sending and receiving multimedia broadcast data in the present invention.

Detailed ways

The scheme of the present invention mainly pre-sets an air interface user plane structure based on CTCH and does not include PDCP, and sets the air interface user plane structure in the multimedia broadcast user plane structure.

Refer to Figure 4 for the set air interface user plane structure. In order to facilitate data processing, the structure only includes three protocol entities, RLC, MAC, and PHY on the UE side, and only includes two protocol entities, RLC and MAC, on the RNC side. Node B side is still only PHY. Neither the UE side nor the RNC side includes the PDCP, and the function of the PDCP to replicate data is implemented by the multimedia service data relay in the RNC. That is to say, PDCP does not need to be added to the air interface user plane structure, but the multimedia service data relay in the RNC needs to transparently copy the multimedia service data to the RLC corresponding to each cell included in the MBMS service area.

Since the MAC c/sh defined by the existing MAC protocol supports CTCH, and CTCH meets the requirements of single-point-to-multipoint transmission of broadcast services, there is no need to define a new MAC-m like the MTCH protocol structure, and RLC can directly pass CTCH Send broadcast data to MAC. And the configuration information of CTCH is carried by BCCH, so there is no need to define a new logical control channel like the MTCH protocol structure.

Based on the air interface user plane structure set above, see Figure 5 for the user plane structure of multimedia broadcasting. UE includes RLC, MAC, and PHY, RNC in UTRAN includes RLC and MAC, and Node B in UTRAN includes PHY.

The multimedia broadcast data transmission process based on the user plane structure shown in Figure 5 is shown in Figure 6, corresponding to the following steps:

Step 601, when broadcasting MBMS service data through Uu, UTRAN first copies the broadcast data from SGSN through the multimedia service data relay, and forwards the copied broadcast data to each All RLCs corresponding to cells.

Step 602, the RLC processes the multimedia broadcast data, and then sends it to the MAC through the CTCH.

Step 603, the MAC processes the received multimedia broadcast data, and sends the processed multimedia broadcast data to the PHY located in the Node B.

Step 604, the Node B sends the received multimedia broadcast data through the air interface.

Steps 605-606, the UE receives the multimedia broadcast data sent by the Node B through its own PHY, and sends it to its own MAC, RLC and other upper layer protocol entities for processing.

Through the above sending and receiving process, the broadcast process of the multimedia broadcast data on the air interface can be completed.

In order to ensure the bearer requirements of the high-speed stream service, the interface of the entity between the BM-SC and the UE can also be set, for example, the Gn interface between the GGSN and the SGSN and the Iu interface between the SGSN and the RNC are both set to GPRS Tunneling Protocol (GTP) tunnel bearer to meet the bearer requirements of high-speed streaming services.

The above descriptions are only preferred embodiments of the solutions of the present invention, and are not intended to limit the protection scope of the present invention.

Claims (6)

1. A method for realizing multimedia broadcast and multicast services through the air interface. The multimedia broadcast data in the broadcast and multicast service center BM-SC passes through the gateway general packet radio service support node GGSN, the service general packet radio service support node SGSN and the wireless network in turn. The network controller RNC performs processing, and is sent to the user equipment UE by the RNC through the air interface, and it is characterized in that the method includes: setting the air interface user plane structure including the radio link control RLC, the medium access control MAC and the physical layer PHY; Based on the air interface user plane structure, the RNC sending the multimedia broadcast data to the UE through the air interface includes the following steps: a. The RNC copies the multimedia broadcast data sent by the SGSN to all RLCs corresponding to each cell contained in the multimedia broadcast multicast service area through the multimedia service data relay; b. RLC processes the received multimedia broadcast data, and sends the processed multimedia broadcast data to MAC through CTCH, MAC processes the received multimedia broadcast data, and sends it to the base station Node B, and Node B passes the air interface Send the received multimedia broadcast data; c. The UE receives the multimedia broadcast data sent by the Node B through the air interface. 2. The method according to claim 1, wherein said setting includes the air interface user plane structure of RLC, MAC and PHY as follows: RLC, MAC and PHY are set on the UE side of the air interface user plane structure, and the RNC Set RLC and MAC on the Node B side, and set PHY on the Node B side. 3. The method according to claim 2, characterized in that in the step b, the MAC sends the processed multimedia broadcast data to the Node B as follows: MAC sends the processed multimedia broadcast data to the node located at the Node B PHY; In step c, the UE receiving the broadcast data sent by the Node B is: the UE receives the broadcast data sent by the Node B through its own PHY. 4. The method according to claim 2 or 3, characterized in that after the step c, it further comprises: the UE sequentially processes the received multimedia broadcast data through MAC and RLC. 5. The method according to claim 1, further comprising: setting the interface between the GGSN and the SGSN as a General Packet Radio Service Tunneling Protocol (GTP) tunnel bearer. 6. The method according to claim 1, further comprising: setting the interface between the SGSN and the RNC as a GTP tunnel bearer.

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