WO2009059549A1

WO2009059549A1 - Method, apparatus and system for transmitting/receiving multimedia broadcast multicast data

Info

Publication number: WO2009059549A1
Application number: PCT/CN2008/072895
Authority: WO
Inventors: Rongdao Yu; Qi Li
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2007-10-31
Filing date: 2008-10-31
Publication date: 2009-05-14
Also published as: CN101425873B; CN101425873A

Abstract

A method, apparatus and system for transmitting/receiving multmedia broadcast multicast data, the method comprises coding multmedia broadcast multicast data using Low-Density Parity-Check (LDPC) code; dividing coded service data into first information and second information; transmitting the first information and second information. A receiver estimates the quality of current channel environment; the first information is merely received when the channel environment is fine; the first information and the second information are received synchronously when the channel environment is not fine.

Description

Multimedia broadcast multicast data transmission/reception method, device and system

The present invention relates to the field of wireless communications, and in particular, to a multimedia broadcast multicast data transmitting method, a receiving method, and a corresponding device and system.

Background technique

Among various mobile packet services, services including video on demand, television broadcasting, video conferencing, online education, interactive games, etc. have a main feature, that is, multiple users subscribing to the service receive the same data at the same time, and such services and general Compared with data, it often has many concurrent users, large amount of data, long duration, and sensitive time delay. Obviously, the ordinary point-to-point transmission method is still used for such services, and the efficiency is very low for a resource-intensive mobile communication network. For this reason, in many communication systems, Multimedia Broadcast Multicast Service (MBMS) technology is introduced for the transmission requirements of this type of broadcast and multicast services. In MBMS technology, a data source can simultaneously transmit point-to-multipoint data to multiple users, and effectively realize network resource sharing, including mobile core network and access network resource sharing, especially air interface resource sharing. The existing MBMS service has the following characteristics: The MBMS service is a point-to-multipoint service, and the base station cannot perform adaptive transmission for each user's channel characteristics, so there is no channel quality feedback link, which is an open loop transmission. At the same time, because there is no link quality feedback, the MBMS service does not have Hybrid Automatic Repeat reQuest (HQQ) and Adaptive Code Modulation (AMC) mechanisms.

Since the MBMS service is a point-to-multipoint transmission, and the user distribution in the cell is relatively random, it can be distributed in various locations of the cell, some users are close to the base station, and some users are far away from the base station, so each user receives a signal attenuation degree. There are different. In order to ensure the effective reception of the MBMS service, in the channel coding, the code rate needs to consider the QoS requirements of most users of the cell, especially the remote users. Thus, for the near-end user, even if the channel conditions are good, only low-speed data far below its receiving capability can be received, resulting in power consumption of the receiver. Low Density Parity Check Codes (LDPC), a linear block code proposed and studied by Gallager in 1962. The LDPC code has a good Hamming distance characteristic. With an iterative decoding algorithm, the LDPC code can approach the Shannon channel capacity limit with low complexity.

The LDPC code is a linear block code whose name is derived from the sparsity of its check matrix. That is, the number of non-zero elements per row (per column) in the check matrix is very rare, and the position is randomly released, most of which The elements are all "0". For an LDPC code with a code length of n bits and an information bit number of k, it can be described by its check matrix ^, and all code words satisfy χ· ^τ =0. Each row of the check matrix represents a check constraint, wherein all the symbol variables corresponding to the non-zero elements constitute a check set, represented by a check equation; each column of the check matrix represents a check of the participation of a symbol variable Constraint, when the column element is not zero, indicates that the symbol variable participates in the check constraint of the row.

The LDPC code is divided into a regular LDPC code and a non-regular LDPC code. Gallager first gave the definition of a regular LDPC code. Specifically, the parity check matrix H of a regular LDPC code satisfies the following three conditions:

(1) Each line of H has p "1";

(2) Each column of H has λ "1";

(3) Both ρ and λ are small compared to the code length and the number of rows in the matrix.

If the code block length is η, the regular LDPC code can be represented by (η, λ, ρ). Example 1 gives a check matrix of (8, 2, 4) codes.

Example 1: A regular (8, 2, 4) code regular LDPC code check matrix H is:

1 0 1 0 1 0 1 0

1 0 0 1 0 1 0 1

H =

0 1 1 0 0 1 1 0

0 1 0 1 1 0 0 1 Generally, in order to study the convenience of the problem, the Tanner graph model corresponding to the LDPC code can be expressed as a bipartite graph. For example, the check matrix H in Example 1 can be equivalently represented by the bipartite graph of FIG. The upper circular point represents the variable node, and the lower square point represents the constraint, that is, the upper side The nodes correspond to each column of the check matrix, the lower node corresponds to each row of the check matrix, and the line between the upper node and the lower node represents a non-"0" element in the check matrix.

When the number of "1"s in each column (row) of the check matrix H is not the same, an irregularity is obtained.

LDPC code.

With Turbo codes, LDPC codes have the following advantages:

(1) The decoding complexity of the LDPC code is lower than that of the Turbo code; and, because the computational complexity of one iteration in the LDPC code decoding algorithm is much lower than the computational complexity of one iteration in the Turbo code decoding algorithm, it can be changed The maximum number of iterations yields the best compromise of "complexity-performance"; in addition, the decoding of LDPC codes can be processed in parallel;

(2) The minimum distance of the binary LDPC code increases linearly with the probability that the code length approaches 1; (3) The LDPC code with superior performance is easily designed according to the arbitrary code length and coding rate;

(4) The LDPC code has no "wrong floor" phenomenon, which is suitable for applications where short frames are applied.

In the prior art, the LDPC code is not used for MBMS service transmission, and the receiving end with different channel environments realizes receiving MBMS service data with a small receiving power.

Summary of the invention

The embodiment of the invention provides a method, a device and a system for transmitting and receiving an MBMS service data, so that the receiving end can receive the MBMS service with a smaller receiving power while ensuring the receiving quality of the service data according to the channel environment in which the receiving end is located. data.

The MBMS service data sending method provided by the embodiment of the present invention includes:

The multimedia broadcast multicast data is encoded by using a low density parity check code LDPC code; the encoded service data is divided into first information and second information;

Sending the first information and the second information.

An embodiment of the present invention provides a multimedia broadcast multicast data receiving method, including:

The receiving end determines the quality of the channel environment in which it is currently located;

When the current channel quality parameter value is greater than or equal to the corresponding threshold value indicating that the channel quality is good, the first information is received according to the time-frequency resource corresponding to the first information; Multimedia broadcast multicast data uses LDPC encoded partial bits;

Receiving the first information and the second information according to the time-frequency resources corresponding to the first information and the second information, respectively, when the current channel quality parameter value is smaller than the corresponding threshold value indicating that the channel quality is good; the first information is the sending end The part of the multimedia broadcast multicast data encoded by the LDPC is transmitted, and the second information is the remaining bits except the first information in the encoded multimedia broadcast multicast data.

The embodiment of the invention further provides a base station, including:

a coding unit, configured to encode the multimedia broadcast multicast data by using a low density parity check code LDPC code;

a processing unit, configured to divide the encoded service data into the first information and the second information, and send, by the sending unit, the first information and the second information.

The embodiment of the invention further provides a mobile terminal, including:

The determining unit is configured to determine the channel environment quality of the current channel; when the current channel quality parameter value is greater than or equal to the corresponding threshold value indicating that the channel quality is good, the first receiving unit is started; when the current channel quality parameter value is When the corresponding threshold value indicating that the channel quality is good is smaller, the second receiving unit is started;

The first receiving unit receives the first information according to the time-frequency resource corresponding to the first information; the first information is a part of the bit that is used by the transmitting end to encode the multimedia broadcast multicast data by using LDPC;

The second receiving unit receives the first information and the second information according to the time-frequency resources corresponding to the first information and the second information, where the first information is the LDPC-encoded multimedia broadcast multicast data sent by the sending end. And a part of the bits, where the second information is the remaining bits except the first information in the encoded multimedia broadcast multicast data.

The embodiment of the present invention further provides a multimedia broadcast multicast service transmission system, including a base station and a mobile terminal, where the base station is configured to encode the multimedia broadcast multicast data by using a low density parity check code LDPC code, and then encode the coded The service data is divided into the first information and the second information and then sent to the mobile terminal; The mobile terminal is configured to determine the quality of the channel environment in which the current channel is located; when the current channel quality parameter value is greater than or equal to the corresponding threshold value indicating the channel quality, the first time information resource corresponding to the first information is received first. The first information is a part of the bits that are LDPC-encoded by the transmitting end to the multimedia broadcast multicast data;

Receiving the first information and the second information according to the time-frequency resources corresponding to the first information and the second information, respectively, when the channel quality parameter value that is currently located is smaller than the corresponding threshold value indicating that the channel quality is good; the first information is And transmitting, by the sending end, a part of bits of the LDPC-encoded multimedia broadcast multicast data, where the second information is the remaining bits except the first information in the encoded multimedia broadcast multicast data.

According to an embodiment of the present invention, the multimedia broadcast multicast data is encoded by using an LDPC code; the encoded service data is divided into the first information and the second information, and then sent to the receiving end. The first information is a part of bits after the LDPC encoding is used by the transmitting end to the multimedia broadcast multicast data; and the second information is the remaining bits except the first information in the encoded multimedia broadcast multicast data. The receiving end determines the channel environment quality of the current location, and when the channel environment in which the current channel is located is good (the channel quality parameter value is greater than or equal to the corresponding threshold value indicating the good channel quality), the time-frequency resource receiving according to the first information is received. First information; when the channel environment in which the current channel is located is different (the channel quality parameter value is smaller than the corresponding threshold value indicating that the channel quality is good), the first information and the first information are respectively received according to the time-frequency resources corresponding to the first information and the second information. Two information. In this way, for a receiving end with a good channel environment, since there is a high signal-to-noise ratio (SNR), only the first information needs to be received, the data demodulation can be successfully completed, and the second information does not need to be received, thereby reducing the receiving time. Reduced receiving power consumption. For the receiving end with poor channel environment, the MBMS service data sent by the transmitting end is obtained by receiving the first information and the second information and performing joint decoding, thereby ensuring the receiving quality of the MBMS service. DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is some embodiments of the present invention, and those of ordinary skill in the art, Other drawings may also be obtained from these drawings without the inventive labor. 1 is a Tanner graph model corresponding to an LDPC code in the prior art;

2 is a flowchart of a step of transmitting MBMS service data by a transmitting end according to Embodiment 1 of the present invention; FIG. 3 is a schematic structural diagram of a sparse matrix according to Embodiment 1 of the present invention;

4 is a second schematic diagram of a sparse matrix structure in Embodiment 1 of the present invention;

5 is a flowchart of a step of transmitting MBMS service data by a transmitting end according to Embodiment 2 of the present invention; FIG. 6 is a flowchart of a step of receiving MBMS service data by a receiving end according to Embodiment 3 of the present invention; Schematic diagram of a base station structure;

FIG. 8 is a schematic structural diagram of a mobile terminal according to an embodiment of the present invention.

detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

An embodiment of the present invention provides a method for transmitting multimedia broadcast multicast data, including:

The multimedia broadcast multicast data is encoded by using an LDPC code; the encoded service data is divided into first information and second information; and the first information and the second information are sent to the receiving end.

The above multimedia broadcast multicast data transmitting method will be described in detail below with reference to the accompanying drawings. Example 1

The basic implementation principle is as follows: Construct a first sparse matrix, which is called a base matrix for convenience of description, so that the multimedia broadcast multicast data encoded by the base matrix can be correctly decoded by the receiving end of the channel environment; Expanding, generating a second sparse matrix, which is convenient for description, is called an enhanced check matrix. For the receiving end of the channel environment difference, all the information encoded according to the enhanced check matrix is received and then decoded to obtain the transmission data of the MBMS service. See Figure 2 for specific steps, including:

Step S101: Construct a first sparse matrix (base matrix) of M rows and N columns, so that the multimedia broadcast multicast data encoded by the base matrix can be correctly decoded by the receiving end of the channel environment.

First, a matrix of the same code rate but a low dimension ^x is constructed, and the base matrix can be expanded by the matrix H _b . The criterion for expansion is that the element "1" in the matrix H _b is replaced by an appropriate zxz dimensional cyclic permutation matrix, and the element "0" in H _b is replaced by a z matrix of zxz, that is, a 3⁄4 or a zxz cycle. The permutation matrix, or a zero matrix of zxz.

In the step S101, the constructed base matrix needs to be satisfied that: the multimedia broadcast multicast data encoded by the base matrix can be correctly decoded by the receiving end of the channel environment, and the channel environment is better than the channel quality parameter value is greater than or It is defined by a corresponding threshold equal to the quality of the channel. For example, the receiving end that makes the Signal Noise Rate (SNR) greater than or equal to the set threshold can correctly decode the multimedia broadcast multicast data encoded by the base matrix, or use other methods that can define the channel quality. The specific threshold or threshold may be negotiated between the network side and the terminal side, or may be notified by the network side according to the situation.

For the basis matrix constructed according to the theory, it can be verified by simulation or experiment whether it meets the condition. It is also possible to determine the basis matrix that satisfies the condition by means of simulation or experiment.

Step S102, expanding the base matrix to generate a second sparse matrix (enhanced check matrix) of the (M+J) row (N+J) column.

The specific way to expand the base matrix, for example:

Add a matrix of 0 rows and J columns to the right side of the base matrix;

Add a sparse matrix of J rows (N+J) columns below the base matrix and the added 0 matrix

He;

The enhancement check matrix H _{enhanced is} composed of a base matrix, a 0 matrix and a sparse matrix He.

A schematic diagram of the structure of the sparse matrix H _{OTA rf} after expanding the base matrix is shown in FIG. 3 , wherein The enhanced check matrix H _e „ _erf consists of three parts:

The first part is M rows and N columns, which is the base matrix Hbasic of M X N;

The second part is the Ho matrix, which is the 0 matrix of Μ χ J;

The third part is the J line (N+J) column He matrix, which is the sparse matrix of J x ( N+J ).

Thus, the obtained enhanced check matrix H _OTAa „ ^ is a sparse matrix of the M′ row N′ column;

among them:

M'=M+J (1)

N'=N+J (2)

Step S103: Perform LDPC encoding on the enhanced check matrix H _e „ _e † MBMS service data to obtain encoded (N+J) bits of service data.

Wherein, in the encoded MBMS service data, the information bit number K is:

Κ= Ν'- Μ'= ( N+J ) - ( M+J ) =N-M (3)

The number of check bits is (M + J) bits. That is, in the encoded (N+J) bits of service data, the first K bits are information bits, and the last (M+J) bits are parity bits.

Step S104: Dividing the encoded service data into the first information and the second information, specifically, including: using the first N bits of the encoded (N+J) bits of service data as the first information; The last J bits in the subsequent (N+J) bits of service data are used as the second information; wherein, M, N, and J are both positive integers.

Step S105: Send the first information and the second information.

The specific transmission method is, for example, transmitting the first information and the second information in a time division multiplexing manner.

Optionally, the method further includes: sending time-frequency resource indication information corresponding to the first information and the second information to the receiving end, so that the receiving end determines, according to the received time-frequency resource indication information, the time-frequency resource that receives the first information and Receiving time-frequency resources of the second information.

The structural diagram of the enhanced check matrix H _e „ _Aa „ ^ generated in the step S102 can also be as shown in FIG. 4 , which differs from the matrix structure shown in FIG. 3 in that:

In Figure 4, the He matrix is designed as a lower triangular sparse matrix, and the starting and ending points of the triangular hypotenuse in Figure 4 The first element of the Nth column of the sparse matrix He and the last element of the (N+J)th column. Each element passing through the hypotenuse of the triangle is "Γ, and the remaining "1" elements in the sparse matrix He are all located in the slash area of the sparse matrix He in Figure 4, that is, all elements in the white triangle area are "0". The enhanced check matrix H _OTAa „ ^ with the structure shown in Fig. 4 can be encoded in an iterative manner, thereby reducing coding complexity. Example 2:

The basic implementation principle is as follows: Construct a sparse matrix, which is called a third sparse matrix for the convenience of description, so that the multimedia broadcast multicast data encoded by the third sparse matrix can be correctly decoded by the receiving end of the channel environment difference; The three sparse matrix performs LDPC encoding on the multimedia broadcast multicast data, and divides the encoded service data into the first information and the second information, where the first information is part of the encoded service data, and the channel environment is good. The receiving end only needs to receive the first information to correctly decode and obtain the transmission data of the MBMS service.

FIG. 5 is a flowchart of a step of sending MBMS service data by a sending end according to Embodiment 2 of the present invention, which specifically includes:

Step S401: Construct a third sparse matrix of M rows and N columns, so that the service data of the multimedia broadcast multicast service coded by the third sparse matrix can be correctly decoded by the receiving end of the channel environment difference. Such as:

First, a matrix of the same code rate but a low dimension ^x is constructed, and the third sparse matrix subjected to LDPC coding is expanded by the matrix H _b . The criterion for expansion is that the element in the matrix H _b is replaced by an appropriate zxz dimensional cyclic permutation matrix, and the element "0" in H _b is replaced by a z matrix of zxz, ie a 3⁄4 or a cyclic permutation of zxz Matrix, or a matrix of 0xz 0.

In the step S401, the constructed third sparse matrix needs to be satisfied: the multimedia broadcast multicast data encoded by the third sparse matrix can be correctly decoded by the receiving end of the channel environment difference, the letter The channel environmental difference can be defined by a channel quality parameter value that is less than a corresponding threshold that characterizes the channel quality. For example, the receiving end that makes the SNR smaller than the set threshold can correctly decode the multimedia broadcast multicast data encoded by the third sparse matrix. Of course, other methods can also be used to characterize the channel quality. The specific threshold or threshold may be negotiated between the network side and the terminal side, or may be notified by the network side according to the situation.

For the third sparse matrix constructed according to the theory, it can be verified by simulation or experiment whether it satisfies the condition. It is also possible to use a simulation or experimental means to determine a third sparse matrix that satisfies the condition.

Step S402: Perform LDPC encoding on the multimedia broadcast multicast data by using the constructed third sparse matrix to obtain the encoded N bits of service data.

Step S403. The service data of the encoded N bits is divided into the first information and the second information, and specifically includes:

Dividing the last M bits of the encoded N bits of service data into a first partial bit and a second partial bit;

The first (N-M) bits of the encoded N bits of service data, and the first partial bits are used as the first information; and the second partial bits are used as the second information.

In the step S403, the last M bits of the encoded N bits of service data are check bits, and the M check bits are divided into two parts. For example, the first part includes M1 check bits, and the second part The part contains M2 check bits, namely: M1+M2=M;

Since the first (NM) bits in the encoded N bits of service data are K information bits, the first information includes the first (NM) bits of the encoded N bits of service data. M1 check bits, that is, the first information includes K information bit numbers and M1 check bits; the second information includes M2 check bits.

Step S404: Send the first information and the second information.

Optionally, the method further includes: transmitting time-frequency resource indication information corresponding to the first information and the second information. And the receiving end, so that the receiving end determines the time-frequency resource for receiving the first information and the time-frequency resource for receiving the second information according to the received time-frequency resource indication information. Example 3:

FIG. 6 is a flowchart of a step of receiving MBMS service data by a receiving end according to Embodiment 3 of the present invention;

Step S501: The receiving end determines the channel environment quality that the current location is located.

In this step S501, the channel environmental quality can be characterized by a plurality of parameters. For example, the signal-to-noise ratio SNR can be used to characterize the channel environmental quality. When the receiving end determines that the current SNR is greater than the set threshold, it determines that the channel environment quality is good; when the SNR is less than or equal to the set threshold, it is determined as The channel environment quality is poor.

When the receiving end determines that the channel environment quality of the current channel is good, the first receiving policy is used, and the following step S502 is performed;

When the receiving end determines that the channel environment quality of the current channel is poor, the second receiving policy is used, and the following step S504 is performed.

Step S502: The receiving end receives the first information sent by the sending end according to the time-frequency resource corresponding to the first information.

The time-frequency resource corresponding to the first information is carried by the time-frequency resource indication information sent by the sending end to the receiving end, and after receiving the time-frequency resource indication information, the receiving end can determine the time-frequency resource occupied by the first information, thereby Receiving the first information sent by the sending end on the corresponding time-frequency resource.

For the method for transmitting the MBMS service data by the sending end provided in the foregoing Embodiment 1, the first information is the first N in the service data of the (N+J) bits after the LDPC encoding is performed by using the enhanced check matrix H _OTAa „ ^ Bits

For the method for transmitting the MBMS service data by the sending end provided in the foregoing Embodiment 2, the first information is a part of the bits that are LDPC-encoded by the transmitting end to the multimedia broadcast multicast data; that is, the number of K information bits including the LDPC encoding Ml check bits. Step S503: The receiving end performs decoding according to the received first information, and acquires MBMS service data sent by the sending end.

Step S504: The receiving end receives the first information and the second information according to the time-frequency resources corresponding to the first information and the second information, respectively.

The time-frequency resource corresponding to the first information and the second information is carried by the time-frequency resource indication information sent by the sending end to the receiving end, and after receiving the time-frequency resource indication information, the receiving end can determine the first information and the second information. The time-frequency resource occupied by the information, so that the first information and the second information sent by the sending end are received on the corresponding time-frequency resource.

For the method for transmitting the MBMS service data by the sending end provided in the foregoing Embodiment 1, the first information is the first N in the service data of the (N+J) bits after the LDPC encoding is performed by using the enhanced check matrix H _OTAa „ ^ The second information is the last J bits in the service data of the (N+J) bits after LDPC encoding using the enhanced check matrix H _enhanced ;

For the method for transmitting the MBMS service data by the sending end provided in the foregoing Embodiment 2, the first information is a part of the bits that are LDPC-encoded by the transmitting end to the multimedia broadcast multicast data; that is, the number of K information bits including the LDPC encoding Ml check bits; the second information is the remaining bits except the first information in the encoded multimedia broadcast multicast data, that is, the M2 check bits are included.

Step S505: The receiving end performs decoding according to the received first information and the second information, and obtains MBMS service data sent by the sending end.

As can be seen from the foregoing embodiment 3, when receiving the MBMS service data, the receiving end first determines the channel environment in which it is currently located, and uses different receiving policies according to different channel environments. When the channel environment is good, the received LDPC coded check bits are small and the MBMS service data can be decoded correctly and effectively. Therefore, while the reception quality is guaranteed, the received and decoded check bits are reduced, thereby Reduced reception time and reduced reception energy consumption. For the receiving end with poor channel environment, the MBMS service data is decoded by all the LDPC-encoded information bits and check bits sent by the transmitting end, thereby ensuring the receiving quality of the MBMS service data. The method for transmitting the MBMS service data according to the foregoing embodiment of the present invention, the embodiment of the present invention further provides a base station 70, and a schematic structural diagram thereof is shown in FIG. 7, which includes:

a coding unit 701, configured to encode the multimedia broadcast multicast data by using a low density parity check code LDPC code;

The processing unit 702 is configured to divide the service data encoded by the coding unit 701 into the first information and the second information;

The sending unit 703 is configured to send the first information and the second information that are divided by the processing unit 702. Preferably, the coding unit 701 further includes:

The matrix construction sub-unit 7011 is configured to construct a sparse matrix for performing LDPC coding, and the coding execution sub-unit 7012 is configured to encode the multimedia broadcast multicast data by using the sparse matrix constructed by the second matrix construction sub-unit 7011. According to the MBMS service data receiving method provided by the foregoing embodiment of the present invention, the embodiment of the present invention further provides a mobile terminal 80, and a schematic structural diagram thereof is shown in FIG.

The determining unit 801 is configured to determine the channel environment quality in which the current channel is located; when the channel quality parameter value currently in the channel is greater than or equal to the corresponding threshold value indicating that the channel quality is good, the first receiving unit 802 is started; When the channel quality parameter value is less than the corresponding threshold value indicating that the channel quality is good, the second receiving unit 803 is activated;

The first receiving unit 802 receives the first information according to the time-frequency resource corresponding to the first information, where the first information is a part of the bit that is used by the transmitting end to encode the multimedia broadcast multicast data by using LDPC;

The second receiving unit 803 receives the first information and the second information according to the time-frequency resources corresponding to the first information and the second information, respectively.

The first information is a part of bits of the multimedia broadcast multicast data encoded by the LDPC, and the second information is the encoded multimedia broadcast multicast data, and the first letter is removed. The remaining bits outside the interest rate.

Preferably, the mobile terminal 80 may further include:

The third receiving unit is configured to receive time-frequency resource indication information corresponding to the first information and the second information that is sent by the sending end, and determine time-frequency resources corresponding to the first information and the second information.

According to another embodiment of the present invention, a base station and a mobile terminal are provided. The embodiment of the present invention further provides a multimedia broadcast multicast service transmission system, including the foregoing base station and a mobile terminal, where: the base station is configured to multicast a multimedia broadcast. The data is encoded by the LDPC code of the low-density parity check code, and the encoded service data is divided into the first information and the second information and then sent to the mobile terminal. The mobile terminal is used to determine the channel environment quality of the current channel. Receiving the first information according to the time-frequency resource corresponding to the first information when the channel environment in which the channel is currently located is good; the first information is a part of the bit that is LDPC-encoded by the transmitting end to the multimedia broadcast multicast data;

The first information and the second information are respectively received according to the time-frequency resources corresponding to the first information and the second information, where the first information is the LDPC code that is sent by the sending end. The multimedia broadcasts a part of bits of the multicast data, and the second information is the remaining bits of the encoded multimedia broadcast multicast data except the first information.

In summary, the embodiment of the present invention encodes the multimedia broadcast multicast data by using the LDPC code; the encoded service data is divided into the first information and the second information, and then sent to the receiving end. The receiving end determines the quality of the channel environment in which the current location is located. When the current channel environment is good (the quality parameter value is greater than or equal to the corresponding threshold value indicating the good channel quality), the time-frequency resource corresponding to the first information is received. When the current channel environment is poor (the quality parameter value is smaller than the corresponding threshold value indicating that the channel quality is good), the first information and the second information are respectively received according to the time-frequency resources corresponding to the first information and the second information. . In this way, for a receiving end with a good channel environment, since the signal-to-noise ratio (SNR) is high, the data demodulation can be successfully completed only by receiving the first information, and the second information does not need to be received, thereby reducing the receiving time. Reduced receiving power consumption. For the receiving end with poor channel environment, the MBMS service data sent by the transmitting end is obtained by receiving the first information and the second information and performing joint decoding, thereby ensuring the receiving quality of the MBMS service. A person skilled in the art can understand that all or part of the process of implementing the above embodiment method can be completed by a computer program to instruct related hardware, and the program can be stored in a computer readable storage medium. In execution, the flow of an embodiment of the methods as described above may be included. The storage medium may be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM). The spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and the modifications of the invention

Claims

Claim

A multimedia broadcast multicast data sending method, comprising:

The multimedia broadcast multicast data is encoded by using a low density parity check code LDPC code; the encoded data is divided into first information and second information;

Sending the first information and the second information.

2. The method of claim 1, further comprising:

When the first information and the second information are sent, time-frequency resource indication information corresponding to the first information and the second information is sent together.

The method according to claim 1, wherein the encoding the multimedia broadcast multicast data by using the low density parity check code LDPC code comprises:

Constructing a first sparse matrix of M rows and N columns, so that the multimedia broadcast multicast data encoded by the first sparse matrix can be correctly received by the receiving end with a channel quality parameter value greater than or equal to a corresponding threshold value indicating that the channel quality is good. Decoding

Expanding the first sparse matrix to generate a second sparse matrix of (M+J) rows (N+J) columns; LDP LDPC encoding the multimedia broadcast multicast data by using the second sparse matrix, and obtaining the coded (N+J) bits of service data;

The dividing the encoded service data into the first information and the second information, specifically includes:

Taking the first N bits of the encoded (N+J) bits of data as the first information; taking the last J bits of the encoded (N+J) bits of data as The second information; wherein, M, N, and J are all positive integers.

The method according to claim 3, wherein the expanding the first sparse matrix to generate a second sparse matrix of the (M+J) row (N+J) column comprises:

Adding a matrix of 0 rows and J columns to the right side of the first sparse matrix;

Adding a sparse matrix He of a J row (N+J) column below the first sparse matrix and the 0 matrix; The second sparse matrix is composed of the first sparse matrix, the 0 matrix, and the sparse matrix He.

The method according to claim 4, wherein the sparse matrix He is a lower triangle sparse matrix; wherein the start and end points of the triangle hypotenuse are the first element and the first column of the Nth column of the sparse matrix He N+J ) The last element of the column.

The method according to claim 3, 4 or 5, wherein the multimedia broadcast multicast data encoded by the first sparse matrix can be represented by a channel quality parameter value greater than or equal to a good channel quality. The receiver corresponding to the threshold is correctly decoded, specifically:

The receiving end that makes the signal to noise ratio greater than or equal to the set threshold can correctly decode the multimedia broadcast multicast data encoded by the first sparse matrix.

The method according to claim 1, wherein the encoding the multimedia broadcast multicast data by using a low density parity check code LDPC code comprises:

Constructing a third sparse matrix of M rows and N columns, so that the service data of the multimedia broadcast multicast service coded by using the third sparse matrix can be smaller than the receiving end of the corresponding threshold value indicating that the channel quality is good. Correct decoding

The LDPC encoding the multimedia broadcast multicast data by using the third sparse matrix to obtain the encoded N bits of service data;

And dividing the last M bits of the encoded N bits of service data into a first partial bit and a second partial bit;

And using the first (N-M) bits of the encoded N bits of service data, and the first part of bits as the first information;

The second partial bit is used as the second information.

The method according to claim 7, wherein the service data of the multimedia broadcast multicast service encoded by the third sparse matrix can be smaller than the corresponding threshold value indicating that the channel quality is good. The receiving end is correctly decoded, specifically: The receiving end that makes the signal to noise ratio smaller than the set threshold can correctly decode the multimedia broadcast multicast data encoded by the third sparse matrix.

A multimedia broadcast multicast data receiving method, comprising:

When the current channel quality parameter value is greater than or equal to the corresponding threshold value indicating the channel quality, the first information is received according to the time-frequency resource corresponding to the first information; the first information is the transmitting end to the multimedia broadcast multicast data. a partial bit encoded by LDPC;

Receiving the first information and the second information according to the time-frequency resources corresponding to the first information and the second information, respectively, when the current channel quality parameter value is smaller than the corresponding threshold value indicating that the channel quality is good; the first information is sent by the sending end The LDPC encodes a part of bits of the multimedia broadcast multicast data, and the second information is the remaining bits of the encoded multimedia broadcast multicast data except the first information.

10. The method of claim 9, further comprising:

The time-frequency resource indication information corresponding to the first information and the second information sent by the transmitting end is received, and time-frequency resources corresponding to the first information and the second information are determined.

A base station, comprising:

a coding unit (701), configured to encode the multimedia broadcast multicast data by using a low density parity check code LDPC code;

The processing unit (702) is configured to divide the encoded service data into the first information and the second information, and the sending unit (703) is configured to send the first information and the second information.

The base station according to claim 11, wherein the encoding unit (701) further comprises:

The matrix construction sub-unit (7011) is configured to construct a sparse matrix for performing LDPC coding, and the coding execution sub-unit (7012) is configured to encode the multimedia broadcast multicast data by using the constructed sparse matrix.

13. A mobile terminal, comprising: The determining unit (801) is configured to determine the channel environment quality in which the current channel is located; when the current channel quality parameter value of the channel is greater than or equal to the corresponding threshold value indicating that the channel quality is good, the first receiving unit is started; when the current channel is When the quality parameter value is less than the corresponding threshold value indicating that the channel quality is good, the second receiving unit is started;

The first receiving unit (802) receives the first information according to the time-frequency resource corresponding to the first information; the first information is a part of the bit that is used by the transmitting end to encode the multimedia broadcast multicast data by using LDPC;

The second receiving unit (803) receives the first information and the second information according to the time-frequency resources corresponding to the first information and the second information, respectively, where the first information is a multimedia broadcast group that is encoded by the transmitting end and is encoded by the LDPC. And playing a part of the bits of the data, where the second information is the remaining bits except the first information in the encoded multimedia broadcast multicast data.

The mobile terminal of claim 13, further comprising:

A multimedia broadcast multicast service transmission system, comprising a base station and a mobile terminal, wherein the base station is configured to encode the multimedia broadcast multicast data by using a low density parity check code LDPC code, and encode the coded The service data is divided into the first information and the second information and then sent to the mobile terminal;

The mobile terminal is configured to determine the quality of the channel environment in which the current channel is located; when the current channel quality parameter value is greater than or equal to the corresponding threshold value indicating the channel quality, the first time information resource corresponding to the first information is received first. The first information is a part of the bits that are LDPC-encoded by the transmitting end to the multimedia broadcast multicast data;