CN101242552A - Data Synchronization Method - Google Patents

Abstract

A method for transmitting data synchronously on an air interface, comprising steps: the MBMS control module receives a message and knows that a certain MBMS service is about to start; the MBMS control module notifies the MBMS data processing module of data multiplexing configuration; the MBMS control module notifies the enhanced Configuration of base station data multiplexing; BM-SC sends MBMS data to the MBMS data processing module. The multiplexed data packets of the present invention may belong to different data streams of the same MBMS service, or may belong to different MBMS services, or even all MBMS services sent in the same frequency band. If the SFN areas of different services are in the same A geographical area, and these services use the same frequency band, the MBMS control module can select the same data processing module for these services, and tell the data processing module and all enhanced base stations under the SFN area that these services are multiplexed together Synchronous processing.

Description

Data Synchronization Method

technical field

The present invention relates to the field of communication, especially in the long-term evolution system, when transmitting broadcast and multicast service (MBMS), how to transmit data synchronously on the air interface.

Background technique

The Mobility Management Entity (MME) and the User Plane Entity (UPE) in the enhanced wireless communication system can be combined in the same entity, and multiple MMEs/UPEs are connected to multiple ENBs , an ENB is linked to an adjacent ENB. In the communication system, the MME and the UPE may also be two entities separated from each other, and the system structure at this time is shown in FIG. 1 . Multiple MMEs are connected to multiple ENBs through S1 interfaces, multiple UPEs are connected to multiple ENBs through S1 interfaces, and one ENB is connected to adjacent ENBs through X2 interfaces. Referring to Fig. 1, the wireless communication system includes a communication backbone network 100, a group of enhanced base stations E-Node B 104 and 105, which together provide services in the routing area TA. The wireless communication system may be, but not limited to, an FDMA-based communication system, a TDMA-based communication system, or a CDMA-based communication system. The communication backbone network 109 includes a mobile management MME103 and a user plane entity UPE102. Each enhanced base station 104 and 105 provides service within a respective communication cell 106 and 107 throughout the routing area. MME103, UPE102, E-NodeB 105, in compliance with practical and feasible standards, provide wireless communication services for mobile phones (hereinafter referred to as MS) 108 working in the communication cell, UPE102 is connected to Anchor101, and receives data sent by the external network from the Anchor. Each of the system components mentioned above are also contemplated to be commercially available.

In order to effectively utilize the resources of the air interface, some services are provided to users in the form of broadcast and multicast, and these services are called Multimedia Broadcast and Multicast Service (Multimedia Broadcast and Multicast Service, hereinafter referred to as MBMS service). Each MBMS service provides services in its own service area. Each cell in the service area has a dedicated control channel to transmit MBMS signaling. In the enhanced wireless communication system, the transmission method of MBMS service is somewhat different from that under 3G. MBMS service can be transmitted in a single-carrier cell. If adjacent cells use the same single carrier to transmit the same MBMS service, and synchronized The way to transmit this MBMS service, the signal received by the user is the superposition of the two signal energies, if the adjacent cell uses the same carrier and transmits the same MBMS service asynchronously, the signal received by the user from the adjacent cell is an interference signal , affecting the user's quality of MBMS reception. Therefore, in the enhanced wireless communication system, a continuous area is defined, and in this area, each enhanced base station uses the same carrier to transmit signals synchronously to improve the quality of MBMS reception of users. This continuous area is called the SFN area.

The SFN (Single Frequency Network) area includes a group of geographically continuous cells, and these cells use the same radio resources to transmit a specific MBMS service synchronously. The SFN area belongs to and uniquely belongs to one MBMS service area. A SFN area only contains cells that are transmitting data.

The service area of MBMS is a specific MBMS Session data transmission area. A multi-cell MBMS synchronization area is a group of cells that cover a continuous area and allocate the same frequency band to MBMS services. This group of cells has the ability and possibility to transmit MBMS data through SFN mode. A multi-cell MBMS synchronization area does not depend on an MBMS service area, and a multi-cell MBMS synchronization area can support one or more SFN areas. For a geographical area and a designated frequency band, only one multi-cell MBMS synchronization area is defined. If multiple multi-cell MBMS synchronization areas are defined in the same geographic area, these multi-cell MBMS synchronization areas are assigned different frequency bands.

Multiple SFN areas may be included in a multi-cell MBMS synchronization area. To reduce interference, adjacent SFNs cannot use the same frequency. If different SFN areas want to use the same frequency, there must be a protection area in between. The protection area is also a group of cells, and the frequency used in the protection area is different from the frequency used in the surrounding SFN area.

Studies have shown that synchronous transmission of MBMS data by all enhanced base stations will bring significant performance improvements. There are different techniques to achieve synchronization of data transmission between enhanced base stations. One is the synchronization method provided by the network. The transmission network achieves synchronization through a clock, and the IEEE1588 protocol can be used. This protocol can coordinate a series of clocks on the enhanced base station and synchronize them with an accuracy of at least a few microseconds. One method is to send synchronization signals to the enhanced base station via a common satellite signal, such as GPS. One method is UE-assisted air interface signal synchronization, which wastes air resources. The method to be adopted has not yet been finalized. No matter which method is adopted, the purpose is to hope that the signals sent by the enhanced base station are synchronized, so as to achieve the best performance.

To receive MBMS data sent by the enhanced base station synchronously, the UE not only requires the enhanced base station to be synchronized, but also needs the data packets sent by the enhanced base station to be the same, so that the UE can jointly receive signals sent by different enhanced base stations. To ensure that the data packets sent by the enhanced base station are the same, the enhanced base station needs to have the same data processing link, then a centralized control node is needed to configure the data processing link of the enhanced base station, for example, the configuration of the enhanced base station has Same RLC/MAC protocol parameters. Hereinafter, we refer to the physical entity where the control module is located as the MCE, and the MCE is set to have the same RLC/MAC configuration for the enhanced base stations in the same SFN range.

MBMS data transmission also needs a data module to forward the data sent from BM-SC to the enhanced base station. Hereinafter, the physical entity where the data module is located is referred to as the DGW. DGW is responsible for sending data to the enhanced base station. DGW includes user plane processing and some Session control functions, such as PDCP function, Session start and end. The interface between the DGW and the enhanced base station is called the S1 interface. The data sent by the DGW is transmitted on the S1 interface of the entire SFN range. When the data is transmitted on an S1 interface, it will be lost or lag behind. Some mechanisms are needed to ensure that even In the case of data loss or lag, the data sent by the enhanced base station can also maintain synchronization.

The control module and the data module may be in one physical entity, or in different physical entities. The MCE and the DGW may be one physical entity, may also be independent physical entities, or may exist on an existing physical entity.

Currently, there are different ways to solve this problem. One way is that it is not necessary to add an absolute time stamp to each packet sent by the DGW. There is a synchronous protocol layer on the DGW. This layer adds a sequence number to each PDCP packet. This sequence number indicates which bit or byte of the data stream the packet starts from, that is, the sequence number is bit-level. Or a sequence number at the byte level. The MCE configures the physical layer resources of all enhanced base stations within the SFN range for a certain MBMS service. After the enhanced base station receives the sequence number, the enhanced base station calculates when it should send it on the air interface. If a packet is lost at the S1 interface, the enhanced base station can calculate when the next packet should be transmitted. When the MBMS service starts, the MCE needs to set when the enhanced base station starts sending the first packet, and this time is an absolute time. Subsequently, data synchronization is maintained spontaneously.

In the current solution, on which physical layer frequency and time resources to send data is configured by the MCE at the beginning of data transmission. Frequency resources can be set at the beginning of data, but at the beginning of data, it is difficult for MCE to know exactly when the MBMS service should be sent. This method does not support the multiplexing of MBMS services. If the rate of MBMS business is very low, it may cause waste of air resources. Therefore, the present invention proposes a method to support multiplexing of MBMS services.

Contents of the invention

Therefore, the purpose of the present invention is to invent how a data processing module adds synchronization information to MBMS data, and then sends it to the enhanced base station, and the base station transmits data synchronously on the air interface according to the synchronization information.

In order to achieve the above object, a method for transmitting data synchronously on an air interface, comprising steps:

a) The MBMS control module receives the message and knows that a certain MBMS service is about to start;

b) The MBMS control module notifies the MBMS data processing module of the data multiplexing configuration;

c) The MBMS control module notifies the enhanced base station of the configuration of data multiplexing;

d) BM-SC sends MBMS data to the MBMS data processing module.

According to the present invention, when the MBMS service starts, the MBMS control module needs to notify the data processing module and the enhanced base station about the configuration of MBMS data multiplexing. The multiplexed data may be different data streams belonging to the same MBMS service, or may belong to different MBMS services, or even all MBMS services sent in the same frequency band. If the SFN areas of these services are in the same geographical area, and these services use the same frequency band, the MBMS control module can set these services to be multiplexed together, and select the same data processing module for these multiplexed services to transmit and process data . If multiple SFN areas are configured for one MBMS service, different SFN areas have different multiplexing configurations. The MBMS control module can select the same data processing module for different SFN areas, or select a corresponding data processing module for each SFN area. The MBMS control module informs the data processing module and the enhanced base station ENB which services are multiplexed together for synchronous processing.

Description of drawings

Fig. 1 is a block diagram of the wireless communication system of the present invention;

Fig. 2 is a schematic diagram of the present invention;

Fig. 3 is the protocol stack of data processing in the present invention;

Fig. 4 is the data data processing process of DGW;

Fig. 5 is the data data processing process of ENB;

Fig. 6 is the first embodiment of the signaling process that MBMS Session starts;

Fig. 7 is the second embodiment of the signaling process that MBMS Session starts;

Fig. 8 is the third embodiment of the signaling process that MBMS Session starts;

Fig. 9 is the fourth embodiment of the signaling flow of MBMS Session initiation.

Detailed ways

Fig. 2 is a schematic structural diagram of MBMS transmission in the LTE system. MCE is the MBMS control module and is responsible for configuring the user plane. MCE configures the enhanced base station through the S3 interface. The configuration of all enhanced base stations within the scope of a SFN is the same. In the example shown in the figure, for a certain MBMS service, the configuration There are two SFN regions. DGW is an MBMS data processing module. DGW receives data from BMSC, processes it, and sends it to all enhanced base stations below the SFN range. There is a control interface S2 between the MCE and the DGW, and the MCE notifies the DGW of data multiplexing information and configuration of the SFN area through S2. The BMSC can send a Session start message to the MCE through the S1 interface.

Fig. 3 is each module and protocol stack of MBMS data processing. The BMSC of the 304 module transmits the MBMS data to the 303 module DGW through the transport layer. After the 303 module DGW receives the MBMS data, it first processes the PDCP data. The PDCP processing includes the header compression function, and then it is processed by the synchronization layer. The synchronization layer is based on Data multiplexing is configured. If there are multiple SFN areas, the configuration of data multiplexing in each SFN area does not have to be the same. Therefore, each SFN area can have a synchronization layer. The PDCP protocol layer is for an MBMS service or an MBMS data flow, and the synchronization layer is for multiplexing MBMS data within a SFN range. The synchronization layer mainly adds a serial number to the data packet, and the ENB sorts the data packet according to the serial number, and transmits data on the air interface in order. If there is multiplexed data, multiple MBMS data are transmitted through one wireless resource, and the synchronization layer adds a serial number to the multiplexed data packet. If there is no data multiplexing, the synchronization layer adds a sequence number to the MBMS data packet processed by PDCP a serial number. This sequence number is at the byte or bit level. The data packets processed by the synchronization layer are transmitted to the enhanced base station ENB through the transport layer. The enhanced base station is processed by the synchronization layer. The synchronization layer arranges the data in order. If lost, the synchronization layer calculates the number of bits of the lost data packet. Data calculation corresponds to the air resource, and no data is transmitted on the corresponding air resource. After the data processed by the synchronization layer is processed by RLC/MAC, it is sent to the air interface through the physical layer. The reception of the UE is the same as that of ordinary services.

Fig. 4 illustrates the data processing flow of module 303 DGW. After the 401DGW receives the data sent from the BMSC of the 304 module, it first performs PDCP processing. In the example shown in the figure, two MBMS data streams are processed by two PDCP entities. The two data streams may belong to the same MBMS service or may belong to different MBMS services. Data stream 1 is processed by 402PDCP1, and data stream 2 is processed by 403PDCP2. As shown in the figure, after data stream 1 is processed by 402PDCP1, two data packets are formed, and the length of each data packet is 100 bits. Data stream 2 is processed by 403PDCP2 to form a data packet with a length of 200 bits. These three data packets are then processed by the synchronization layer. This synchronization layer is for a certain SFN range. At the beginning of MBMS, the synchronization layer knows that data stream 1 and data stream 2 need to be multiplexed, and the synchronization layer will uniformly add sequence numbers to the three data packets. The data processed by the synchronization layer is 405. For example, the first packet of data stream 1 is the first packet to be processed synchronously. The sequence number added by the synchronization layer to this packet is 0, because this data packet starts from 0 bits. of. The second packet processed by the synchronization layer is the packet of data stream 2, and the sequence number added to it by the synchronization layer is 100, because the length of the previous packet is 100 bits. The second packet starts with 100 bits. The sequence number of the third packet is 300 because the packets preceding it totaled 300 bits. Then, the data packet is sent to all enhanced base stations below the SFN range through the transport layer.

Figure 5 is the process of data processing by ENB. In step 501, the synchronization layer of the ENB receives the MBMS data packet, and the multiplexed data packets are sent to the same synchronization layer entity. In step 502, the ENB judges whether there is packet loss according to the bit or byte sequence number of the packet header. For example, if ENB receives a packet with SN 100 and length 200, and then ENB receives another packet with SN 400, ENB can know that a packet with length 100 is lost. If there is a data packet loss, go to step 503, and the ENB synchronization layer will form a special packet of the same length according to the length of the lost data. There are some special values in this packet, and then go to step 504, and the RLC and MAC layers can send this packet It is processed in the same way as a normal data packet, except that this data packet is not transmitted on the air interface. Or, the synchronization layer notifies the MAC layer that a packet is lost, the length of the loss and the bit from which it is lost. The MAC layer calculates the corresponding air interface resource according to the lost length and the starting position, and does not transmit any data on this resource. If there is no data packet loss, the synchronization layer removes the SN of the data packet, and then sends the data packet to the lower layer, and carries out the processing of the 504 step RLC and the MAC layer.

In order to realize the data processing process in Figure 4 and Figure 5, in the signaling process at the beginning of the MBMS Session, the MCE needs to configure the DGW data multiplexing information, and the DGW adds sequence numbers to the multiplexed data packets according to the data multiplexing information. Fig. 6 is the first embodiment of the signaling flow of MBMS Session initiation.

Step 601, when the MBMS service starts, the BMSC sends a "Session Start" message to the MBMS control entity MCE. The message includes the MBMS service identifier, the service quality parameters of the service, and the time when the MBMS data starts to be sent.

Step 602, after the MCE receives the message, the MCE saves the information, determines the scope of the SFN area, which ENBs are included in the SFN area, the configuration of the data protocol layer of all ENBs in the SFN area, and the configuration of data multiplexing. The quality of service determines whether to multiplex with existing services. If the service being transmitted on a certain air resource cannot fully use this air resource, for example, the rate of the service being transmitted is very low, and the allocated resource block can Supports higher transmission rates. If the MBMS service to be started immediately can use the remaining resources, that is, the allocated resource block can support the simultaneous transmission of these two MBMS services, the MCE can determine the MBMS service and the ongoing transmission. The services are multiplexed in the same air resource, or the MCE receives two MBMS service start messages, and the MCE can decide that the two MBMS services are multiplexed in the same air resource. Of course, the multiplexing is not limited to two MBMS services, and more MBMS services can be multiplexed together. The MCE sends a 602 message "Session Start" to the DGW. The message includes SFN configuration information and data multiplexing information. The data multiplexing information includes at least different MBMS service identifiers multiplexed on the same air resource.

The Session start message at step 602 includes:

-sfn-locale-settings

-Settings for data multiplexing

The DGW sends a 603 message "Session Start Response" to the MCE, indicating that the message in step 602 has been received.

Step 604, the MCE sends a "Session Start" message to all ENBs in each SFN area, the message includes the indication of the SFN area, the configuration information of the protocol layer for transmitting MBMS data, and the protocol layer configuration information includes the radio link layer (Radio Link Control , hereinafter referred to as RLC), media access layer (Media Access Control, hereinafter referred to as MAC) and physical layer configuration information, as well as data multiplexing configuration, data multiplexing configuration is also the configuration of the synchronization layer on the ENB, the message also contains Contains the address information of the DGW that transmits MBMS data. The MCE can select a DGW to transmit MBMS data, and the MCE tells the ENB the address information of the DGW in order for the ENB to join the multicast group.

In step 605, the ENB sends a message "Session Start" to the UE. The message contains the configuration information of the protocol layer for transmitting MBMS data, including the configuration information of the PDCP layer, RLC layer, MAC layer and physical layer. The message also contains MBMS service information, such as the service identifier TMGI, the time when the service starts, whether it is required The UE sends an uplink response message to count the number of users. UE receives the message, if the network requires the UE to send a response message to collect user data in the message in 605, the UE will initiate a response message in step 606, otherwise, the uplink message in 606 will not be sent.

Step 607, ENB sends "Session start response" to MCE. If in step 605 the network requires the UE to send a response message to count the number of users, the message in step 607 may also include the number of users to receive the MBMS service. The MCE sends the message "Session start response" to the BMSC through step 608 .

In step 609, the ENB initiates the joining process of the IP multicast group. This joining process is an existing technology. There are many implementation methods, for example, the ENB can send an IGMP join message to the DGW, and the DGW sends an IGMP join message to the BMSC in step 610 .

In step 611, the BMSC sends data to the downstream DGW that has joined the MBMS.

In step 612, the DGW performs data processing. The flow of data processing is shown in FIG. 4, and the processing of the PDCP layer and the synchronization layer is performed. The DGW adds a PDCP header and a synchronization sequence number to the MBMS data packet.

In step 613, the DGW sends data to the downstream ENB that has joined the MBMS.

Step 614, the ENB transmits the MBMS data on the allocated physical resources.

Fig. 7 is the second embodiment of the signaling flow of MBMS Session initiation.

Step 701, when the MBMS service starts, the BMSC sends a "Session Start" message to the MBMS control entity MCE. The message includes the MBMS service identifier, the service quality parameters of the service, and the message also includes the time when the service starts.

Step 702, after the MCE receives the message, the MCE saves the information, determines the scope of the SFN area, which ENBs are included in the SFN area, the configuration of the data protocol layer of all ENBs in the SFN area, and the configuration of data multiplexing. The quality of service determines whether to multiplex with existing services. If the service being transmitted on a certain air resource cannot fully use this air resource, for example, the rate of the service being transmitted is very low, and the allocated resource block can Supports higher transmission rates. If the MBMS service to be started immediately can use the remaining resources, that is, the allocated resource block can support the simultaneous transmission of these two MBMS services, the MCE can determine the MBMS service and the ongoing transmission. The services are multiplexed in the same air resource, or the MCE receives two MBMS service start messages, and the MCE can decide that the two MBMS services are multiplexed in the same air resource. Of course, the multiplexing is not limited to two MBMS services, and more MBMS services can be multiplexed together. Then the MCE sends a "Session Start" message to all ENBs in each SFN area. The message includes the indication of the SFN area and the configuration information of the protocol layer for transmitting MBMS data. The protocol layer configuration information includes the configuration information of RLC, MAC and physical layer. There is also the configuration of data multiplexing, which is also the configuration of the synchronization layer on the ENB, and the message can also include the time when the service starts.

In step 703, the ENB sends a message "Session Start" to the UE. The message contains the configuration information of the protocol layer for transmitting MBMS data, including the configuration information of the PDCP layer, RLC layer, MAC layer and physical layer. The message also contains MBMS service information, such as the service identifier TMGI, the time when the service starts, whether it is required The UE sends an uplink response message to count the number of users. The UE receives the message, if the network requires the UE to send a response message to collect user data in the message in 703, the UE will initiate a response message in step 704, otherwise, the uplink message in 704 will not be sent.

Step 705, ENB sends "Session start response" to MCE. If the network requires the UE to send a response message to count the number of users in step 703, the message in step 705 may also include the number of users to receive the MBMS service. The message at 705 also includes the tunnel ID allocated by the ENB for the MBMS data, and the ENB is used to receive the MBMS data.

The MCE sends 706 a message "Session Start" to the DGW. The message includes SFN configuration information and data multiplexing information. The data multiplexing information includes at least different MBMS service identifiers multiplexed on the same air resource. The message at 706 also includes the identifier of the tunnel used by the ENB to receive MBMS data.

The Session start message in step 706 includes:

-SFN locale settings (such as SFN logo)

-Settings for data multiplexing

- Tunnel identifier for downlink transmission of MBMS data

The UPE sends a 707 message "Session Start Response" to the MCE, the message includes the tunnel ID allocated by the DGW for receiving the MBMS, and the 707 message is also used to indicate that the DGW has received the message of the 706 step.

The MCE sends a message "Session Start Response" to the BMSC through step 708, and the message includes the tunnel ID allocated by the DGW for receiving the MBMS.

In step 709, the BMSC sends the MBMS data to the downstream DGW, and the data is sent through the tunnel allocated by the DGW for the MBMS.

In step 710, the DGW performs data processing. The flow of data processing is shown in FIG. 4, and the processing of the PDCP layer and the synchronization layer is performed. The DGW adds a PDCP header and a synchronization sequence number to the MBMS data packet.

In step 711, the DGW sends MBMS data to the downstream ENB, and the data is sent through the tunnel allocated by the ENB for MBMS.

In step 712, the ENB transmits MBMS data on the allocated physical resources.

Fig. 8 is a third embodiment of the signaling flow of MBMS Session initiation.

Step 801, when the MBMS service starts, the BMSC sends a "Session Start" message to the MBMS data processing entity DGW. The message includes the MBMS service identifier, the service quality parameters of the service, and the start time of the service.

Step 802, DGW saves the information after receiving the message, and then sends a message "Session Start" to the control entity MCE, the message includes the MBMS service identifier, service quality parameters, and service start time.

Step 803, MCE saves information, determines the scope of the SFN area, which ENBs are included in the SFN area, the configuration of the data protocol layer of all ENBs in the SFN area, and the configuration of data multiplexing. Existing services are multiplexed. If the service being transmitted on a certain air resource does not fully use this air resource, for example, the rate of the service being transmitted is very low, and the allocated resource block can support a higher transmission rate. , if the MBMS service that is about to start can use the remaining resources, that is, the resource block allocated in this block can support the simultaneous transmission of the two MBMS services, the MCE can decide to multiplex the MBMS service and the service being transmitted in the same block The air resource, or the MCE has received two MBMS service start messages, and the MCE may decide to multiplex the two MBMS services in the same air resource. Of course, the multiplexing is not limited to two MBMS services, and more MBMS services can be multiplexed together. Then the MCE sends a "Session Start" message to all ENBs in each SFN area. The message includes the indication of the SFN area, the configuration information of the protocol layer for transmitting MBMS data, and the configuration information of the protocol layer includes the configuration of RLC, MAC and physical layer. Information, as well as the configuration of data multiplexing, the configuration of data multiplexing is also the configuration of the synchronization layer on ENB. In step 804, the ENB sends a message "Session Start" to the UE. The message contains the configuration information of the protocol layer for transmitting MBMS data, including the configuration information of the PDCP layer, RLC layer, MAC layer and physical layer. The message also contains MBMS service information, such as the service identifier TMGI, the time when the service starts, whether it is required The UE sends an uplink response message to count the number of users. The UE receives the message, if the network requires the UE to send a response message to collect user data in the message in 804, the UE will initiate a response message in step 805, otherwise, the uplink message in 805 will not be sent.

Step 806, ENB sends "Session start response" to MCE. The message includes the tunnel ID allocated by the ENB for receiving MBMS data. If the network requires the UE to send a response message to count the number of users in step 804, the message in 806 may also include the number of users who will receive the MBMS service.

In step 807, the MCE sends a "Session Start Response" message to the DGW. The message contains the tunnel identifier allocated by the ENB for the MBMS data, the configuration information of the SFN, and the data multiplexing information. The multiplexing information includes at least multiplexing in the same block Different MBMS service identifiers on air resources.

The Session start response message in step 807 includes:

-SFN locale settings (such as SFN logo)

-Settings for data multiplexing

- Tunnel identifier for downlink transmission of MBMS data

In step 808, the DGW sends a "Session Start Response" to the BMSC, and the message includes the tunnel ID allocated by the DGW for receiving MBMS data.

In step 809, the BMSC sends the MBMS data to the downstream DGW, and the data is sent through the tunnel allocated by the DGW for the MBMS.

In step 810, the DGW performs data processing. The data processing flow is shown in FIG. 4 , and the PDCP layer and synchronization layer processing are performed. The DGW adds a PDCP header and a synchronization sequence number to the MBMS data packet.

In step 811, the DGW sends MBMS data to the downstream ENB, and the data is sent through the tunnel allocated by the ENB for MBMS.

Step 812, the ENB transmits MBMS data on the allocated air resources.

Fig. 9 is the fourth embodiment of the signaling flow of MBMS Session initiation.

Step 901, when the MBMS service starts, the BMSC sends a "Session Start" message to the MBMS data processing entity DGW. The message includes the MBMS service identifier, the service quality parameters of the service and the start time of the service.

Step 902, DGW saves the information after receiving the message, and then sends a message "Session start" to the control entity MCE, the message includes the address information of the DGW, and the message also includes the MBMS service identifier, service quality parameters, and service start time.

Step 903, MCE saves information, determines the scope of the SFN area, which ENBs are included in the SFN area, the configuration of the data protocol layer of all ENBs in the SFN area, and the configuration of data multiplexing. Existing services are multiplexed. If the service being transmitted on a certain air resource does not fully use this air resource, for example, the rate of the service being transmitted is very low, and the allocated resource block can support a higher transmission rate. , if the MBMS service that is about to start can use the remaining resources, that is, the resource block allocated in this block can support the simultaneous transmission of the two MBMS services, the MCE can decide to multiplex the MBMS service and the service being transmitted in the same block The air resource, or the MCE has received two MBMS service start messages, and the MCE may decide to multiplex the two MBMS services in the same air resource. Of course, the multiplexing is not limited to two MBMS services, and more MBMS services can be multiplexed together. Then the MCE sends a "Session Start" message to all ENBs in each SFN area. The message contains the indication of the SFN area, the configuration information of the protocol layer for transmitting MBMS data, and the configuration information of the protocol layer includes the configuration information of RLC, MAC and physical layer. , as well as the configuration of data multiplexing, which is also the configuration of the synchronization layer on the ENB, and the message also includes the address information of the DGW.

In step 904, the ENB sends a message "Session Start" to the UE. The message contains the configuration information of the protocol layer for transmitting MBMS data, including the configuration information of the PDCP layer, RLC layer, MAC layer and physical layer. The message also contains MBMS service information, such as the service identifier TMGI, the time when the service starts, whether it is required The UE sends an uplink response message to count the number of users. The UE receives the message, if the network requires the UE to send a response message to collect user data in the message in 904, the UE will initiate a response message in step 905, otherwise, the uplink message in 905 will not be sent.

Step 906, ENB sends "Session Start Response" to MCE. If in step 804 the network requires the UE to send a response message to count the number of users, the message in step 906 may also include the number of users to receive the MBMS service.

In step 907, the MCE sends a "Session Start Response" message to the DGW. The SFN information in the message includes data multiplexing information, and the multiplexing information includes at least different MBMS service identifiers multiplexed on the same air resource.

The Session start response message in step 907 includes:

-SFN locale settings (such as SFN logo)

-Settings for data multiplexing

Step 908, DGW sends "Session start response" to BMSC.

In step 909, the ENB initiates the joining process of the IP multicast group. This joining process is an existing technology. There are many implementation ways, for example, the ENB can send the IGMP join message to the DGW, and the DGW sends the IGMP join message to the BMSC in step 910 .

Step 911, BMSC sends MBMS data to downstream DGW.

In step 912, the DGW performs data processing. The flow of data processing is shown in FIG. 4, and the PDCP layer and the synchronization layer are processed. The DGW adds a PDCP header and a synchronization sequence number to the MBMS data packet.

In step 913, the DGW sends data to the downstream ENB that has joined the MBMS.

Step 914, the ENB transmits MBMS data on the allocated air resources.

Although the invention has been described in terms of four illustrated embodiments, it should be noted that these embodiments are intended to illustrate, not limit, the invention. Those skilled in the art can easily modify, add and delete any steps in these embodiments without departing from the spirit and scope of the present invention.

Claims (15)

1. A method for transmitting data synchronously over an air interface, comprising the steps of: a) The MBMS control module receives the message and knows that a certain MBMS service is about to start; b) The MBMS control module notifies the MBMS data processing module of the data multiplexing configuration; c) The MBMS control module notifies the enhanced base station of the configuration of data multiplexing; d) BM-SC sends MBMS data to the MBMS data processing module. 2. The method according to claim 1, further comprising, the BMSC sends a Session start message to the MBMS control module. 3. The method according to claim 1, characterized in that in step b), the MBMS control module sends a Session start message to the MBMS data processing module. 4. The method according to claim 3, characterized in that data multiplexing is different in different SFN ranges. 5. The method according to claim 1, characterized in that in step c), the MBMS control module sends a Session start message to the enhanced base station to notify the configuration of data multiplexing. 6. According to the method according to claim 5, it is characterized in that the data multiplexing configuration includes multiplexing service identification. 7. The method according to claim 1, wherein in step a), the data processing module sends a Session start message to the MBMS control module. 8. The method according to claim 1, wherein in step b), the MBMS control module sends a Session start response message to the MBMS data processing module to notify the configuration of data multiplexing. 9. The method according to claim 1, wherein in step c), the MBMS control module sends a Session start message to the enhanced base station to notify the configuration of data multiplexing. 10. method according to claim 1, is characterized in that described step d) also comprises: Perform PDCP processing on the received MBMS data; Perform synchronization layer processing after PDCP processing on the data; The data packets processed by the synchronization layer are transmitted to the enhanced base station through the transport layer. The enhanced base station performs synchronization layer processing on the data. The synchronization layer arranges the data in order and sends the data to the air interface through the physical layer. 11. The method according to claim 10, wherein the PDCP processing comprises two PDCP processing. 12. The method according to claim 10, characterized in that the synchronous processing is to add a synchronous sequence number to the data packets multiplexed together. 13. The method according to claim 10, wherein the processing of data by the enhanced base station comprises: The enhanced base station judges whether there is packet loss; If there is a packet loss, the synchronization layer of the enhanced base station forms a special packet of the same length according to the length of the lost data; The RLC/MAC layer performs the same processing on the special packet as the common data packet. 14. The method according to claim 10, wherein the processing of data by the enhanced base station comprises: The enhanced base station judges whether there is packet loss; If there is a packet loss, the synchronization layer of the enhanced base station notifies the MAC layer of the length of the lost packet and from which bit it is lost; The MAC layer calculates the corresponding air interface resource according to the lost length and the starting position. 15. The method according to claim 12, wherein the synchronization processing module calculates the corresponding air transmission time according to the synchronization sequence number.

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