CN1467938A - A transmission method for realizing multimedia broadcast and multicast services - Google Patents

Abstract

The invention discloses a transmission method for realizing multimedia broadcast and multicast services, which is applied in a wireless communication system. The method at least includes: A. A wireless network controller according to the type of service required by users who register multimedia broadcast and multicast services, Each user in the same cell is assigned a respective group ID to form a group user; B. The base station generates a group ID scrambling sequence according to the group ID, and uses the group ID scrambling sequence for multimedia broadcast and multicast services The first part of the information of the control channel is scrambled to form the first time slot information of the channel; C. The base station allocates the multimedia broadcast and multicast service downlink channel according to the channel quality of the current signal received by the group users, and transmits the downlink channel through this channel to Group users send data packets. The invention realizes high-speed data broadcasting and multicasting services under limited radio resources, saves radio frequency resources, and improves the capacity of cell users.

Description

A transmission method for realizing multimedia broadcast and multicast services

technical field

The invention relates to the technical field of wireless communication, in particular to a transmission method of multimedia broadcasting and multicasting services in a digital wireless communication system.

Background technique

In the third-generation mobile communication Wideband Code Division Multiple Access (WCDMA, Wideband Code Division Multiple Access) system, the channel transmission time interval (TTI: Transmission Time Interval) in WCDMA is generally 10ms, and each TTI contains 15 time slots (slots). ). In order to adapt to high-speed data services, fast response and large data volume transmission required by high-speed data transmission, a high-speed downlink shared channel (HS-DSCH: High Speed Downlink Share Channel) is introduced. This channel is a time-division code-division shared channel, every 2ms It is a TTI, and each TTI contains 3 slots.

Along with the HS-DSCH channel, there is a downlink high-speed shared control channel (HS-SCCH: High Speed Share Control Channel), which is used to indicate to the user (UE: User) whether to receive the decoded data of a certain TTI on a certain HS-DSCH. After receiving and decoding, the UE feeds back the acknowledgment/denial information (ACK/NACK: Acknowledge/Unacknowledge) and channel of whether the decoded data block is correct or not through the uplink High Speed Dedicated Physical Control Channel (HS-DPCCH: High SDeed Dedicate Physical Control Channel). The quality indicator (CQI: Channel Quality Indicator) is given to the base station. The base station determines whether to retransmit the erroneous data block according to the ACK/NACK, judges the quality of the channel according to the CQI, and determines parameters such as the modulation and coding mode and power for transmission. In support of point-to-point transmission, each UE feeds back the ACK/NACK and its CQI information of its own user through the HS-DPCCH channel, and the base station performs retransmission and adjusts the modulation and coding level according to the ACK/NACK and CQI fed back by each UE (MCS: Modulation and Coding Selections).

Referring to Fig. 1, Fig. 1 shows the channel structure of HS-SCCH. The channel structure includes the first part (Part1), the second part (Part2) and the cyclic redundancy check code (CRC) part, wherein the Part1 part and the Part2 part obtain the CRC code through CRC calculation, and the 10-bit user identification (UE ID) The encoding of the CRC is included in the calculation of the CRC. Part1 contains 8bit, 7bit is the information allocated by the channel code set, 1bit is modulation information, Part2 contains 13bit, respectively, 6bit indicates the transmission block size, 3bit hybrid automatic retransmission request information (HARQ: Hybrid ARQ), 3bit Redundant information, 1bit new transport block indication information, CRC code is 16bit. Part1, Part2, and CRC are respectively coded with a code rate of 1/2 convolutional code (8 tail bits), code rate matched and interleaved to become 120 bits, forming 3 slots, and each slot is 40 bits.

The above Part1 information is encoded with a code rate of 1/2 convolutional code (8 tail bits), code rate matching and interleaving to scramble the Part1 information. The implementation process is as follows: as shown in Figure 2, the base station converts the HS -The Part1 information in the SCCH channel is coded by a convolutional encoder with a code rate of 1/2 and matched with a code rate matcher to form 40-bit Part1 information; at the same time, the 10-bit user identification is group-encoded to form a 32-bit code sequence, Repeat the first 8 bits of the code sequence to form a 40-bit scrambling sequence, and then XOR the 40-bit scrambling sequence with the 40-bit Part1 information to form the first slot, so that the receiver can decode Part1 in time Information, to obtain the code set allocation information and modulation information corresponding to the UE ID, so as to determine whether there is information transmitted to itself on the main MBMS downlink channel, and if so, receive and decode it.

With the development of mobile communication technology, multimedia mobile services are becoming more and more popular. However, the current base station (NodeB) and radio network controller (RNC: Radio Network Controller) structure is only suitable for point-to-point high-speed data services. Consider the air interface requirements of Multimedia Broadcast and Multicast Service (MBMS: Multimedia Broadcast and Multicast Service), such as: reducing the resource occupation of wireless communication channels, performing high-speed data transmission, and so on. It can also be seen from the information scrambling process of Part 1 in Figure 2 that in the current wireless mobile communication system, the HS-SCCH uses the user ID to generate the scrambling code sequence, so the basic services supported are all point-to-point, that is, from From one client to another, multicast cannot be supported.

On the other hand, the transmission of current multimedia broadcast and multicast services generally adopts a broadcast channel (BCH: Broadcast Channel) or a dedicated channel for each user. Although there is a broadcast channel in the WCDMA system, the broadcast channel transmits the random access codes and access time slots available in the cell, as well as the diversity method used, etc., which are used for UE registration in the cell, and the rate is only about 30kbps , cannot be used for multimedia broadcasting with high transmission rate requirements; while using dedicated channels to transmit multimedia broadcasting and multicast services, the same information is transmitted on each user's dedicated channel, wasting wireless resources.

Contents of the invention

The purpose of the present invention is to provide a transmission method of multimedia broadcasting and multicasting services, which realizes the transmission of multimedia broadcasting and multicasting services on the basis of the existing high-speed downlink shared channel structure, so as to increase the transmission rate and reduce resource occupation.

The present invention is realized through the following technical solutions:

A transmission method for realizing multimedia broadcast and multicast services, applied in a wireless communication system, the method at least includes:

A. The radio network controller assigns each user a respective group identification (Group ID) according to the service type required by the user who registers the multimedia broadcast and multicast service, and forms a group user;

B. The base station generates a group ID scrambling sequence according to the group ID, and uses the group ID scrambling sequence to scramble the first part of information of the multimedia broadcast and multicast service control channel to form the first time slot of the channel information;

C. The base station allocates downlink channels for multimedia broadcast and multicast services according to the channel quality of the signals currently received by the group users, and sends data packets to the group users through the channels.

The above method may further include, storing the multimedia broadcast and multicast service registered by the user in a home location register (HLR: Home Location Register), and recording the user's unique identifier in the corresponding multimedia broadcast and multicast service server to form the user's Authentication basis, multimedia broadcast and multicast service management center (MBMSMC: MBMS Manage Center) generates the service identification (MBMS ID) of this service, and the mobile switching center passes the wireless network controller and the base station according to the user's authentication basis and service identification request to establish a radio link resource. Wherein, the subscriber identity is an International Mobile Subscriber Identity (IMSI: International Mobile Subscriber Identity), and the multimedia broadcast and multicast service server is a virtual value-added data server (VAS: Virtual Application Service).

The above method may further include,

D. According to the first time slot information of the multimedia broadcast and multicast service control channel, the group user judges whether there is information transmitted to itself on the multimedia broadcast and multicast service downlink channel, and if so, receives the current multimedia broadcast and multicast The data packet sent by the service downlink channel, and feeds back the receiving information of the current data packet to the base station through the uplink multimedia broadcast and multicast service feedback channel; if there is no information transmitted to itself, no processing is performed, and the next delivery is waited for data packets;

E. The base station processes the erroneous data packets according to the correct or erroneous information of the received data packets fed back in step D.

Wherein, the multimedia broadcast and multicast service downlink channel described in step C is a main multimedia broadcast and multicast service downlink channel; or the multimedia broadcast and multicast service downlink channel is a pair of main multimedia broadcast and multicast service Downlink channel, secondary multimedia broadcast and multicast service downlink channel. In step D, the base station receives the data packet delivered by the downlink channel of the current primary multimedia broadcast and multicast service. The group identifier can be sent to users who register for multimedia broadcast and multicast services through the broadcast channel in the system to form broadcast service transmission. The group identifier can be issued through dedicated channels of users who register for multimedia broadcast and multicast services, forming multicast service transmission.

Further, the step A further includes that the user who registers the multimedia broadcast and multicast service reports the channel quality of the currently received signal to the radio network controller through the measurement of the pilot frequency of the base station, and the radio network controller reports the channel quality of the currently received signal to the radio network controller according to the channel quality. Users of broadcast and multicast services are grouped.

Described step B further comprises,

B01) The first part of information of the multimedia broadcast and multicast service control channel is coded by a code rate 1/2 convolutional encoder and matched by a code rate matcher to form the first part of information of 40 bits;

B02) Block encoding group identification to form a 32-bit code sequence, repeating the first 8 bits of the code sequence to form a 40-bit group identification scrambling sequence;

B03) XOR operation is performed on the 40-bit group ID scrambling sequence and the 40-bit first part of information to form the first time slot information of the multimedia broadcast and multicast service control channel.

The processing of the error data packet in the step E further includes, if the base station receives the information that the data packet is received incorrectly fed back by any one of the group users, then retransmit the respective information to all the group users on the downlink channel of the main multimedia broadcast and multicast service. lost packets. If the base station receives information that the data packets fed back by one or more group users are incorrectly received, then the group users whose data packets are received correctly will monitor the main multimedia broadcast and multicast service control channel and receive the main multimedia broadcast and multicast service New data packets downlinked from the downlink channel; group users who report incorrect reception of data packets listen to the secondary multimedia broadcast and multicast service control channel and the primary multimedia broadcast and multicast service control channel, and receive the secondary multimedia broadcast and multicast service downlink channel Retransmit lost data packets, and simultaneously receive new data packets downlinked from the main multimedia broadcast and multicast service downlink channel. If a user in a group of users has a high probability of incorrectly receiving information fed back by a data packet within a period of time, the base station removes the user from the group of users and re-allocates wireless link resources for the user. For the data transmitted on the auxiliary downlink channel, the base station assumes that the channel meets the transmission quality. If the group user still cannot correctly receive the retransmitted data on the channel, it will request retransmission through the radio link control layer protocol.

In addition, the group identifier is 10 bits.

The above-mentioned multimedia broadcast and multicast service control channel may be a primary multimedia broadcast and multicast service control channel, or may be a secondary multimedia broadcast and multicast service control channel.

The above-mentioned feedback receiving information includes information about correctly received data packets, information about incorrectly received data packets, and channel quality indication information.

The present invention realizes high-speed data broadcasting and multicasting services under limited wireless resources by applying the existing public channel—high-speed downlink shared channel, and setting group user identifiers, saving wireless frequency resources and improving The cell uses the capacity of the user; by processing the ACK/ACK and CQI information fed back by the group UEs belonging to the same GroupID according to a certain strategy, the processing efficiency of the feedback information by the base station is improved, the burden on the base station is reduced, and the transmission efficiency is improved. reliability; by allocating the main MBMS downlink channel and the auxiliary MBMS downlink channel, when the quality of the main MBMS downlink channel is poor, the auxiliary MBMS downlink channel is used to retransmit data, thereby improving the transmission quality and ensuring correct data transmission.

Description of drawings

FIG. 1 is a schematic diagram of a channel structure of an HS-SCCH;

FIG. 2 is a schematic diagram of Part1 information in the channel structure of scrambling HS-SCCH with a scrambling sequence formed by UE ID in the prior art;

Fig. 3 is the schematic diagram of the Part1 information in the channel structure of the scrambling sequence scrambling HS-SCCH that the present invention forms with Group ID;

Fig. 4 is a schematic diagram of implementing broadcast and multicast service transmission services.

Detailed ways

In order to make the object, technical solution, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and examples.

The MBMS service has the characteristics of transmitting the same information to multiple UEs in the cell at the same time, and the amount of information transmitted is relatively large. Since the BCH channel is not suitable for transmitting multimedia information with a relatively large amount of data, a dedicated channel is used to transmit the same information to each UE. information wastes resources.

Aiming at the characteristics of MBMS service, the present invention utilizes the existing common channel—high-speed downlink shared channel to realize multimedia broadcast and multicast service. The present invention sets the high-speed data channel to include main MBMS downlink channel, main MBMS control channel, auxiliary MBMS downlink channel, auxiliary MBMS control channel and uplink MBMS feedback channel.

Both the primary MBMS downlink channel and the secondary MBMS downlink channel are high-speed downlink shared channels, which have the same channel structure as the HS-DSCH in the prior art WCDMA. The main MBMS downlink channel is characterized by short TTI, high-order modulation, Turbo code coding, and shared channel, which is suitable for transmitting large amounts of data, receiving and decoding by multiple UEs simultaneously, and retransmitting lost data blocks. The secondary MBMS downlink channel is characterized by low modulation and coding orders and low transmission rate to ensure transmission quality.

The structure of the primary MBMS control channel and the secondary MBMS control channel is the same as the HS-SCCH structure of the prior art, that is, the same as the HS-SCCH structure shown in Figure 1. The difference is that the base station scrambles the Part1 information process shown in Figure 2 The 10-bit UE ID is replaced by the 10-bit MBMS group ID (Group ID) assigned by the RNC according to the service type. As shown in Figure 3, the Part1 information is coded by a code rate 1/2 convolutional encoder and matched with a code rate matcher to form 40-bit Part1 information; at the same time, the 10-bit Group ID is grouped and encoded to form a 32-bit code sequence, repeating the first 8 bits of the code sequence to form a 40-bit Group ID scrambling sequence, and then XOR the 40-bit Group ID scrambling sequence and the 40-bit Part1 information to form the first slot. In this way, the channel structure is fully compatible with the channel structure of the original WCDMA system, and the group UE can obtain the code set allocation information and modulation information corresponding to the Group ID according to the information in Part1 of the main MBMS control channel, thereby judging the main MBMS downlink channel If there is any information sent to itself, if there is, it will receive and decode; otherwise, it will not perform any processing and wait to receive the next data packet.

The structure of the uplink MBMS feedback channel is the same as that of the HS-DPCCH channel in the prior art. The difference is that, for group UEs belonging to the same Group ID, each UE will feed back ACK/NACK and CQI information to the base station on the shared main MBMS downlink channel through its own uplink feedback channel, and the base station will handle it according to a certain strategy The feedback information. In point-to-point transmission, each UE feeds back ACK/NACK and CQI information to the base station for its main MBMS downlink channel through its own uplink feedback channel, and the base station processes the information fed back by each UE separately.

The implementation process of multimedia broadcast and multicast service transmission is described below.

For the MBMS service, firstly, the UE needs to register the service. The UE's MBMS service registration is stored in the home location register as a basis for authentication. The corresponding MBMS server also records the unique identifier of the mobile phone registered for the MBMS service, such as the International Mobile Subscriber ID. The aforementioned MBMS server may be various virtual value-added data servers. In one or several Mobile Switching Center (MSC) areas, there exists an MBMS Management Center. When this MBMS service occurs, the MBMS service entity sends a request to MBMSMC, and MBMSMC establishes a relationship with MSC to generate the MBMS service identifier, and MSC requests to establish related radio link resources through RNC and NodeB.

During the initial establishment process, the UE registered for the MBMS service can report the current channel quality of the RNC through the measurement of the NodeB pilot. For the UEs in a cell (CELL), the RNC performs grouping according to the channel quality of the signal currently received by each UE. Each group has an MBMS Group ID assigned by RNC.

For each MBMS service, MBMSMC establishes a connection with RNC through MCS. Although there are multiple groups in one cell, or multiple groups in multiple cells, and each group may have different MBMS services, there is only a unique MBMSID service connection on the Iu interface between RNC and MSC.

As shown in Figure 4, the RNC can establish an MBMS group according to the MBMS ID and allocate wireless resources. After the base station receives the message that the RNC establishes an MBMS group, there is only one group for the broadcast service, and the base station can issue the MBMS Group ID to the Each UE. In other cases, including multicast, the base station sends the MBMS Group ID to each UE through the dedicated channel signaling of each UE; each UE feeds back the confirmation information of receiving the Group ID to the base station, and the base station feeds back the radio resource establishment confirmation information to the RNC , to complete the initial setup process.

On the RNC side, the RNC allocates different primary MBMS downlink channels, ie, HS-DSCH channels, according to the channel conditions of each group of UEs. For groups with better channel conditions, the assigned main MBMS downlink channel has a higher modulation mode and coding efficiency, so that the data transmission rate is high. For groups with poor channel quality, the assigned main MBMS downlink channel has a lower transmission rate to ensure correct data transmission.

After receiving the data packet of the main MBMS downlink channel, the UE obtains the code set allocation information and modulation information corresponding to the Group ID according to the information in the Part1 part of the main MBMS control channel, and judges whether there is a transmission on the main MBMS downlink channel according to the Group ID. Give yourself information, if there is, receive and decode it, and perform decoding and CRC check.

For UEs in a group, each UE feeds back ACK/NACK and CQI information to the base station through an uplink feedback channel. Different from point-to-point transmission, in point-to-point transmission, the base station sends new data packets to the UE through the main MBMS downlink channel of each UE, and according to the ACK/NACK and CQI fed back by each UE for its main MBMS downlink channel Perform retransmission and MCS adjustment. In broadcast or multicast service transmission, the base station sends new data packets to the group UEs belonging to the same Group ID through a main MBMS downlink channel, and each user in the group UE feeds back its own data packet for a main MBMS downlink channel. ACK/NACK and CQI information, the base station makes a decision on whether to retransmit and adjust the MCS according to a certain strategy for the feedback information of UEs belonging to the same Group ID.

When the base station sends a new data packet through the main MBMS downlink channel and the group UE receives it successfully, the group UE feeds back the decoding correctness, ACK, and CQI information through the uplink MBMS feedback channel; when the group UE fails to receive it, the group UE passes The uplink MBMS feedback channel feeds back decoding failure, NACK, and CQI information. At this time, the base station can handle it in the following manner, as shown in Figure 4:

1) As long as there is a NACK, the base station retransmits its respective lost data packets to all group users on the main MBMS downlink channel, and then transmits new data packets.

2) If only individual group UEs feed back NACK, for example, one user or more than one user feeds back NACK, new data blocks are still transmitted on the main MBMS downlink channel. Since each group UE is monitoring the main MBMS control channel at the same time, it can Whether the currently received and decoded data block is a new data block is judged according to the identifier indicating the new data block on the main control channel. Among them, the group UE that feeds back ACK receives the new data block transmitted on the primary MBMS downlink channel; the group UE that feeds back NACK monitors the secondary MBMS control channel, and judges the currently received data block according to the identifier indicating the new data block on the secondary MBMS control channel. Whether the decoded data block is the decoded data block that failed to be decoded in the previous TTI and was retransmitted on the secondary MBMS downlink channel; if yes, receive the decoded data block retransmitted on the secondary MBMS downlink The channel modulation mode and coding efficiency are low, and the transmission rate is low to ensure the transmission quality, and at the same time receive new data blocks transmitted on the main MBMS downlink channel. For the secondary MBMS downlink channel, since there is no corresponding uplink feedback channel, the base station can meet the quality transmission by default. If a UE still cannot correctly receive the retransmitted data on the secondary MBMS downlink channel, it will pass the higher layer radio link control (RLC) The layer protocol requests a retransmission.

3) If a certain UE in a certain group of UEs feedbacks a high probability of NACK within a certain period of time, and the CQI information indicates that the channel quality has deteriorated, and in this case, it is impossible to normally receive and decode data on the main MBMS downlink channel, then The base station feeds back the NACK and CQI information to the RNC, and the RNC removes the UE from the MBMS group, and the base station notifies the UE to stop receiving the MBMS group service, and re-allocates radio link resources for the UE.

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 (18)

1, a kind of transmission method of realizing MBMS is applied to it is characterized in that in the wireless telecommunication system that this method comprises at least:

A. radio network controller identifies for each user in the same sub-district distributes cohort separately according to the required type of service of user of registration MBMS, forms the cohort user;

B. the base station generates cohort sign scramble sequence according to the cohort sign, and with this cohort sign scramble sequence first's information of MBMS control channel is carried out scrambling and handle, and forms first gap information of this channel;

C. the MBMS down channel is distributed according to the channel quality of the current received signal of cohort user in the base station, and issues packet by this passage to the cohort user.

2, method according to claim 1, it is characterized in that, this method further comprises, the MBMS of user's registration is deposited in Home Location Register, and at corresponding this user's of MBMS server record unique identification, form user's authentication foundation, MBMS administrative center produces the service identification of this business, and mobile switching centre sets up air-link resources according to user's authentication foundation and service identification by the request of radio network controller and base station.

3, method according to claim 1 is characterized in that, this method further comprises,

D. the cohort user is according to first gap information of MBMS control channel, judge whether the information of passing to oneself is arranged on the MBMS down channel, if have then receive the packet that current MBMS down channel issues, and give the base station by the reception information of up MBMS feedback channel feedback current data packet;

E. the base station receives correct according to step D institute feedback data bag or error message is handled the misdata bag.

4, method according to claim 1 is characterized in that, the described MBMS down channel of step C is a main MBMS down channel.

5, method according to claim 1 is characterized in that, the described MBMS down channel of step C is a pair of main MBMS down channel, auxilliary MBMS down channel.

According to claim 3,4 or 5 described methods, it is characterized in that 6, the base station receives the packet that current main MBMS down channel issues among the step D.

7, method according to claim 1, it is characterized in that, described steps A further comprises, the user of registration MBMS is by reporting the channel quality of current received signal to the measurement of base station pilot to radio network controller, and radio network controller divides into groups according to the user of channel quality to the registration MBMS.

8, method according to claim 1 is characterized in that, described cohort sign is handed down to the user who registers MBMS by the broadcast channel in the system, forms broadcast traffic transmissions.

9, method according to claim 1 is characterized in that, the user of described cohort sign by registration MBMS dedicated channel separately issues, and forms multicast or broadcast traffic transmissions.

10, method according to claim 1 is characterized in that, described step B further comprises,

B01) first's information via code check of MBMS control channel is 1/2 convolution coder coding and code check adaptation coupling, forms first's information of 40 bits;

B02) the block encoding cohort identifies, and forms the sign indicating number sequence of 32 bits, repeats first 8 bit of this yard sequence, forms the cohort sign scramble sequence of 40 bits;

B03) the cohort sign scramble sequence of 40 bits and first's information of 40 bits are carried out XOR, form first gap information of MBMS control channel.

11, according to claim 3,4 or 5 described methods, it is characterized in that, described step e further comprises the processing of misdata bag, if the base station receives the information that the packet error of any one cohort user feedback receives, then retransmit the packet of losing separately to the cohort user that all receive the misdata bag at main MBMS down channel.

12, according to claim 3 or 5 described methods, it is characterized in that, described step e further comprises the processing of misdata bag, if the base station receives the information that the packet error of one or more cohort user feedback receives, then the correct cohort user who receives of feedback data packet monitors main MBMS control channel, and receives the new data packets that passes under the main MBMS down channel; The cohort user that the feedback data packet mistake receives information monitors auxilliary MBMS control channel and main MBMS control channel, receive the packet of auxilliary MBMS down channel retransmission of lost, and receive the new data packets that passes under the main MBMS down channel simultaneously.

13, method according to claim 12, it is characterized in that, described step e further comprises the processing of misdata bag: acquiescence auxilliary MBMS down channel in base station satisfies the quality of transmission, if the cohort user still can't correctly receive the data that retransmit on this channel, then retransmit by the wireless chain control layer agreement request.

14, method according to claim 3, it is characterized in that, described step e further comprises the processing of misdata bag, if the user among the cohort user is frequent at the probability of the information of the packet error reception of a period of time internal feedback, then this user is removed in the base station from this cohort user, distributes air-link resources for this user again.

15, according to claim 1 or 10 described methods, it is characterized in that described cohort is designated 10 bits.

According to claim 1 or 10 described methods, it is characterized in that 16, described MBMS control channel is main MBMS control channel, perhaps is auxilliary MBMS control channel.

17, method according to claim 3 is characterized in that, the described feedback reception of step D information comprises information, the channel quality indication (CQI) information that the correct information that receives of packet, packet error receive.

18, method according to claim 2 is characterized in that, described user ID is an IMSI International Mobile Subscriber Identity, and described MBMS server is virtual supplementary data services device.

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