CN103780550A - Anti-fading wireless signal framing modulation method for single frequency network in multimedia broadcasting - Google Patents

Abstract

The invention discloses a multi-media broadcasting single frequency network anti-fading wireless signal framing modulation method, which is a framing modulation scheme in which space domain, time domain and frequency domain are mixed. The training sequence optimization design, signal generation mode and signal selection method of the multi-media broadcast single frequency network anti-fading wireless signal framing modulation method of the present invention are easy to process and restore the original signal of the OFDM signal at the receiver end, and have a low peak-to-average power ratio , short synchronization time, anti-channel fading, controllable multi-service and other advantages.

Description

Framing Modulation Method of Anti-fading Wireless Signal in Multimedia Broadcasting Single Frequency Network

technical field

The invention belongs to the field of wireless communication, and more specifically relates to a method for framing and modulating anti-fading wireless signals of a multimedia broadcasting single frequency network.

Background technique

Digital TV multimedia broadcasting single frequency network wireless transmission system, as an important part of digital TV wireless multimedia broadcasting, the development of its related technologies is closely related to people's quality of life, and therefore has received extensive attention from people. Digital TV wireless multimedia broadcasting related technologies and related industries are industries with rapid development and good market prospects in the field of communication and computer. In terms of technologies related to digital TV wireless multimedia broadcasting, countries are currently focusing on how to provide low-cost, reliable and high-speed mobile solutions for digital TV wireless multimedia broadcasting in a complex wave propagation environment. Multimedia broadcast single frequency network anti-fading wireless signal transmitter framing modulation technology is the key technology of digital TV wireless multimedia broadcasting system, which plays a decisive role in the performance of the whole system, and is the object of everyone's key research.

Due to the rapid development of digital signal processing technology and integrated circuit technology, the system realization of Orthogonal Frequency Division Multiplexing (OFDM) technology becomes easier and easier. Because OFDM multi-carrier transmission technology has many advantages such as simple structure, high spectrum utilization rate, and anti-frequency selectivity and channel time variation, it has attracted much attention and has been deeply researched and applied in Xdsl, broadband mobile communication, broadband wireless local area network, It is widely used in many fields such as digital TV wireless multimedia broadcasting.

The high peak-to-average power ratio (PAPR) of OFDM signals has high requirements on the linear range of amplifiers and digital-to-analog converters. If the linear range of the system cannot meet the signal changes, it will cause signal distortion and signal spectrum changes. , resulting in the destruction of the orthogonality between sub-channels, resulting in mutual interference and deteriorating system performance. Therefore, it is necessary to consider how to reduce the occurrence probability of high peak power signals in OFDM signals and reduce the impact of nonlinear distortion.

The networking mode of single frequency network (that is, several transmitting stations transmit the same signal on the same frequency at the same time to achieve reliable coverage of a certain service area) can greatly improve the wireless transmission system of digital TV multimedia broadcasting single frequency network. Spectrum utilization. In the actual SFN communication environment, the performance of the digital TV multimedia broadcasting SFN wireless communication system is affected by factors such as synchronization time, clock jitter, channel fading, and channel interference. The framing modulation method of each multimedia broadcasting anti-fading wireless signal transmitter in the single frequency network is a key technology for realizing reliable digital TV multimedia broadcasting single frequency network wireless transmission.

Using the digital TV multimedia broadcasting single frequency network wireless transmission system to provide controllable multi-services such as free TV broadcasting, paid TV broadcasting, confidential information transmission, and multimedia value-added services is a reflection of the new generation of digital TV multimedia broadcasting single frequency network wireless transmission system to meet social needs. .

Based on the above background, the present invention proposes an anti-fading wireless signal framing modulation method for multimedia broadcast single frequency network aimed at the actual communication environment, which can meet the requirements of high-level interleaved coding modulation data rate controllable multi-service digital television multimedia broadcast single frequency network wireless transmission needs.

For a more in-depth understanding of the patent background, please refer to the following literature:

R.V.Nee, R.Prasad. "OFDM for wireless multimedia communications". Boston: Artech House, 2000.

Y. Wu, S. Hirakawa, U.H. Reimers, and J. Whitaker. "Overview of digital television development," Proceedings of the IEEE, Special Issue on Global Digital Television: Technology and Emerging Services, pp.8-21, Jan.2006.

M.S.Richer, G.Reitmeier, T.Gurley, G.A.Jones, J.Whitaker, and R.Rast. "The ATSC digital television system," Proceedings of the IEEE, Special Issue on Global Digital Television: Technology and Emerging Services, pp. 37-43, Jan. 2006.

U.Ladebusch and C.A.Liss. "Terrestrial DVB (DVB-T): A broadcast technology for stationary portable and mobile use," Proceedings of the IEEE, Special Issue on Global Digital Television: Technology and Emerging Services, pp.183-194, .2006.

M. Takada and M. Saito. "Transmission systems for ISDB-T," Proceedings of the IEEE, Special Issue on Global Digital Television: Technology and Emerging Services, pp.251-256, Jan.2006.

Contents of the invention

Aiming at the wireless problem of multi-service digital TV multimedia broadcasting single frequency network with controllable data rate of high-level interleaving code modulation, the invention proposes a frame modulation method for anti-fading wireless signal of multimedia broadcasting single frequency network.

A kind of multimedia broadcast single frequency network anti-fading wireless signal framing modulation method that the present invention proposes is characterized in that it comprises the following steps:

1) The network data manager of the single frequency network forms an FFT concatenated interleaved coded modulation data block in the frequency domain through RS coding, convolutional interleaving, LDPC coding, symbol modulation, and symbol interleaving of the input data bit stream, and RS means Reed -Solomon, LDPC means Low Density Parity Check, the length of the FFT concatenated interleaved coded modulation data block is K, and the value of K is an even number;

2) The network data manager of the single frequency network uses a space-frequency encoder with a code rate of 1 to modulate the FFT concatenated interleaved coded modulation data block formed in the frequency domain to each multimedia broadcast anti-fading wireless signal transmission in the single frequency network Form space-frequency modulation FFT concatenated interleaving coding modulation data blocks on the machine branch, and adjust the time synchronization of each multimedia broadcast single frequency network anti-fading wireless signal transmitter branch to ensure that all transmitters in the network are at the same time for the space frequency Modulation FFT cascaded interleaving encoding modulation data blocks for processing;

3) Each multimedia broadcast anti-fading wireless signal transmitter in the single frequency network adopts IFFT to transform the space-frequency modulation FFT concatenated interleaved coded modulation data block into the space-frequency modulated time domain discrete concatenated interleaved coded modulated data sample block D _total = [d ₀ ,d ₁ ,...,d _K-2 ,d _K-1 ];

4) Each multimedia broadcasting anti-fading wireless signal transmitter in the single frequency network demultiplexes the data sample blocks modulated by space-frequency modulation time-domain discrete concatenated interleaving coding and modulates them according to each space-frequency modulation time-domain discrete cascading interleaving coding modulation Sequential parity of the data samples is sequentially separated to generate space-frequency modulation time-domain discrete concatenated interleaved coding modulation data sample odd sub-block _Dodd =[d ₀ , d ₂ ,..., d _K-4 , d _K-2 ] and Space-frequency modulation time-domain discrete concatenated interleaving coding modulation data sample even sub-block D _even = [d ₁ , d ₃ ,..., d _K-3 , d _K-1 ];

生成模式3为

生成模式4为

生成模式5为

生成模式6为

生成模式7为D_new＝[D^* _奇，D_偶]，生成模式8为

生成模式9为

生成模式10为

生成模式11为

生成模式12为

生成模式13为D_new＝[D_奇，D^* _偶]，生成模式14为

生成模式15为

生成模式16为

生成模式17为

生成模式18为

比较18种生成模式合成的空频调制时域离散级联交织编码调制数据样值块D_new，选取其中具有最低峰均功率比的降峰均功率比空频调制时域离散级联交织编码调制数据样值块并将降峰均功率比空频调制时域离散级联交织编码调制数据样值块

所对应采用的生成模式信息发送给业务指标序列设置单元，其中，D^* _奇表示对空频调制时域离散级联交织编码调制数据样值奇子块D_奇的各空频调制时域离散级联交织编码调制数据样值进行共轭运算处理而得到的空频调制时域离散级联交织编码调制数据样值子块；D^* _偶表示对空频调制时域离散级联交织编码调制数据样值偶子块D_偶的各空频调制时域离散级联交织编码调制数据样值进行共轭运算处理而得到的空频调制时域离散级联交织编码调制数据样值子块；5) Each multimedia broadcast anti-fading wireless signal transmitter in the single frequency network uses the peak-to-average power ratio adjustment unit to discretely concatenate and interleave coded and modulated data sample odd sub-block D _odd for space-frequency modulation and time-domain discrete for space-frequency modulation The concatenated interleaved coded modulation data sample block _Deven performs signal power adjustment and corresponding signal processing and recomposes a new space-frequency modulation time-domain discrete cascaded interleaved coded modulated data sample block D _new , when the new space-frequency modulation The domain discrete concatenated interleaved coded modulation data sample block D _new is obtained by the following generation mode, the generation mode 1 is D _new = [D _odd , D _even ], and the generation mode 2 is

Generate schema 3 as

Generate schema 4 as

Generate schema 5 as

Generate schema 6 as

Generation mode 7 is D _new = [D ^* _odd , D _even ], generation mode 8 is

Generate schema 9 as

Generate schema 10 as

Generate schema 11 as

Generate schema 12 as

Generation mode 13 is D _new = [D _odd , D ^* _even ], generation mode 14 is

Generate schema 15 as

Generate schema 16 as

Generate schema 17 as

Generate schema 18 as

Comparing the space-frequency modulation time-domain discrete concatenated interleaving coded modulation data block D _new synthesized by 18 generation modes, and selecting the one with the lowest peak-to-average power ratio with reduced peak-to-average power ratio data sample block And reduce the peak-to-average power ratio space-frequency modulation time-domain discrete concatenated interleaved coded modulation data sample block

The generated mode information correspondingly adopted is sent to the service index sequence setting unit, wherein, D ^* _odd represents each space-frequency modulation time-domain discrete level for the space-frequency modulation time-domain discrete concatenated interleaved coded modulation data sample odd sub-block D _odd The space-frequency modulated time-domain discrete concatenated interleaved coded modulated data sample sub ^- block obtained by _conjugating the interleaved coded modulated data samples; The space-frequency modulated time _-domain discrete concatenated interleaving coded modulation data sample sub-block obtained by performing conjugate operation processing on each space-frequency modulated time-domain discrete concatenated interleaved coded modulated data sample value of the value even sub-block Deven;

6) Each multimedia broadcast anti-fading wireless signal transmitter in the single frequency network inserts a service index sequence after the training sequence to form a discrete sample block of the time domain training sequence in the time domain. The service index sequence contains and uniquely expresses the single frequency network Each system parameter and business mode information of each multimedia broadcasting anti-fading wireless signal transmitter;

7) Each multimedia broadcast anti-fading wireless signal transmitter in the single frequency network inserts the cyclic prefix as a guard interval into the reduced peak-to-average power ratio space-frequency modulation time-domain discrete concatenated interleaved coded modulation data sample block to form a reduced peak-to-average power ratio Space-frequency modulated time-domain cyclic prefix discrete concatenated interleaved coded modulation data sample block, as the frame body, the length of the cyclic prefix is C;

8) Each multimedia broadcasting anti-fading wireless signal transmitter in the single frequency network inserts the time-domain training sequence discrete sample block, that is, the frame header, into the peak-to-average power ratio space-frequency modulation time-domain cyclic prefix discrete concatenated interleaving coded modulation data sample The value block is the frame body to form a signal frame;

9) Each multimedia broadcast anti-fading wireless signal transmitter in the single frequency network adopts a square root raised cosine roll-off filter to shape the signal pulse of the signal frame;

10) Each multimedia broadcast anti-fading wireless signal transmitter in the single frequency network up-converts the baseband signal to the carrier.

According to the framing modulation method of the anti-fading wireless signal of the multimedia broadcasting single frequency network, it is characterized in that: the peak-to-average power ratio of each multimedia broadcasting anti-fading wireless signal transmitter in the single frequency network is discretely cascaded and interleaved in space frequency modulation time domain The coded modulation data sample block is demultiplexed by the space-frequency modulation time-domain discrete concatenated interleaved coded modulated data sample block and separated in turn according to the sequence parity of each space-frequency modulated time-domain discrete concatenated interleaved coded modulated data sample The generated space-frequency modulation time-domain discrete concatenated interleaving coded modulation data sample odd sub-block and space-frequency modulation time-domain discrete concatenated interleaved coded modulation data sample even sub-block are adjusted for signal power and corresponding signal processing and passed through a specially designed 18 kinds of generation modes are re-synthesized; the training sequence of each multimedia broadcast anti-fading wireless signal transmitter in the single frequency network is composed of the first training sequence and the second training sequence; the first training sequence is composed of constant envelope zero autocorrelation CAZAC sequence Each symbol of B and pseudo-random PN sequence A is alternately inserted into a new sequence and a cyclic prefix of length G; the second training sequence is composed of constant envelope zero autocorrelation CAZAC sequence-B ^* and pseudo-random PN sequence A ^* Each symbol of B is alternately inserted into a new sequence and a cyclic prefix of length G; B ^* means to perform conjugate operation processing on each symbol of B, A ^* means to perform conjugate operation processing on each symbol of A, B and A have the same symbol length L; the cyclic prefix length G of the first training sequence and the second training sequence is 1/8 of the symbol length L of the first training sequence and the second training sequence; each multimedia in the single frequency network The cyclic prefix length C of the broadcast anti-fading wireless signal transmitter signal frame is 1/16 of the length K of the FFT concatenated interleaving code modulation data block; the service index sequence of each multimedia broadcast anti-fading wireless signal transmitter in the single frequency network has pseudo The random characteristic is realized by a set of shifted m-sequences; each different service index sequence of each multimedia broadcasting anti-fading wireless signal transmitter in the single frequency network contains and uniquely expresses each multimedia broadcasting anti-fading wireless signal in the single frequency network The system parameters and business mode information of the signal transmitter; the FFT concatenated interleaving coded modulation data block of each multimedia broadcast anti-fading wireless signal transmitter in the single frequency network is composed of sub-carriers, and the frequency interval of sub-carriers is 2KHz, 4KHz, 1KHz One of them; the code rate of the space-frequency coder is 1; the code rate of the LDPC code is one of 1/4, 1/2, 5/8, 3/4 and 7/8; the symbol modulation is QPSK, One of 16QAM, 32QAM, 64QAM, 64APSK, 256APSK, 1024APSK, the symbol constellation mapping method adopts Gray code mapping; the symbol interleaving adopts random interleaving method.

Features of the present invention:

The invention is a framing modulation scheme in which space domain, time domain and frequency domain are mixed. The space-frequency modulation time-domain discrete concatenated interleaving coded modulation data sample block demultiplexing of the present invention and sequentially separated according to the sequence parity of each space-frequency modulated time-domain discrete concatenated interleaved coded modulated data sample value to generate the space-frequency modulated time Domain discrete concatenated interleaved coded modulation data sample odd sub-block and space-frequency modulation time-domain discrete concatenated interleaved coded modulated data sample even sub-block and its corresponding signal power adjustment and signal processing, through 18 kinds of specifically designed reduction Peak-to-Average Power Ratio Space-Frequency Modulation Time-Domain Discrete Concatenated Interleaved Coded Modulation Data Sample Block Generation Mode and Reduced Peak-to-Average Power Ratio with Minimum Peak-to-Average Power Ratio Space-Frequency Modulation Time-Domain Discrete Concatenated Interleaved Coded Modulated Data Sample Block The selection method can not only make full use of the high maximum peak power of the OFDM signal, but the probability of the high peak power signal is very low. When the number of subcarriers is large, the real part (or imaginary part) of the OFDM signal is a complex Gaussian random process and the amplitude obeys The characteristics of the Rayleigh distribution can effectively change the power distribution law of the framed signal with low complexity to reduce the peak-to-average power ratio. The generation mode adopted requires a small amount of additional information to be sent, and it is easy to process and recover at the receiver to obtain OFDM The original signal of the signal, while not destroying the orthogonality characteristics of the subcarrier signal and not generating additional nonlinear distortion. The training sequence in the signal frame of each multimedia broadcasting anti-fading wireless signal transmitter in the single frequency network is obtained by the constant envelope zero autocorrelation CAZAC sequence and the pseudo-random PN sequence through specific optimization design. Each multimedia broadcasting in the single frequency network The signal frame of the anti-fading wireless signal transmitter is formed by inserting the discrete sample block of the time domain training sequence, that is, the frame header, into the reduced peak-to-average power ratio, space-frequency modulation, time domain cyclic prefix, discrete concatenated interleaved coded modulation data sample block, that is, the frame body , these ensure that the anti-fading wireless signal receiver of multimedia broadcasting single frequency network can realize fast and accurate frame synchronization, frequency synchronization, time synchronization, estimation of channel transmission characteristics, and reliable tracking of phase noise and channel transmission characteristics. The cyclic prefix is inserted as a guard interval into the peak-to-average power ratio space-frequency modulation time-domain discrete concatenated interleaved coded modulation data sample block to form a signal frame body, which can reduce the gap between the signal frame header and the frame body concatenated interleaved coded modulated data Interfering effects. The cascaded interleaving coding and modulation of the input data increases the diversity order, which makes the communication system have good bit error characteristics in the multipath fading channel. Each different service index sequence of each multimedia broadcast anti-fading wireless signal transmitter in the single frequency network contains and uniquely expresses each system parameter and business mode information of each multimedia broadcast anti-fading wireless signal transmitter in the single frequency network, It can make the digital TV multimedia broadcast single frequency network wireless transmission system able to provide controllable multi-services such as free TV broadcast, paid TV broadcast, confidential information transmission, and multimedia value-added services to meet social needs. The framing modulation method of the present invention has low peak-to-average power ratio, short synchronization time, small clock jitter, anti-channel fading, anti-channel interference, and can provide high-level interleaved coding and modulation data rate controllable multi-service digital TV multimedia broadcast single frequency network Wireless transmission and many other advantages.

Description of drawings

Fig. 1 is a schematic diagram of an embodiment of a transmitter of a method for framing and modulating anti-fading wireless signals in a multimedia broadcasting single frequency network according to the present invention.

Fig. 2 is a schematic diagram of an embodiment of transmitter signal framing modulation according to the anti-fading wireless signal framing modulation method for multimedia broadcast single frequency network of the present invention.

Detailed ways

Specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

According to the embodiment of the transmitter of the multimedia broadcast single frequency network anti-fading wireless signal framing modulation method proposed by the present invention, as shown in Figure 1, carry out according to the following steps:

1) The network data manager of the single frequency network forms an FFT concatenated interleaved coded modulation data block in the frequency domain through RS coding, convolutional interleaving, LDPC coding, symbol modulation, and symbol interleaving of the input data bit stream, and RS means Reed -Solomon, LDPC means Low Density Parity Check, the length of the FFT concatenated interleaved coded modulation data block is K, and the value of K is an even number;

2) The network data manager of the single frequency network uses a space-frequency encoder with a code rate of 1 to modulate the FFT concatenated interleaved coded modulation data block formed in the frequency domain to each multimedia broadcast anti-fading wireless signal transmission in the single frequency network Form space-frequency modulation FFT concatenated interleaving coding modulation data blocks on the machine branch, and adjust the time synchronization of each multimedia broadcast single frequency network anti-fading wireless signal transmitter branch to ensure that all transmitters in the network are at the same time for the space frequency Modulation FFT cascaded interleaving encoding modulation data blocks for processing;

3) Each multimedia broadcast anti-fading wireless signal transmitter in the single frequency network adopts IFFT to transform the space-frequency modulation FFT concatenated interleaved coded modulation data block into the space-frequency modulated time domain discrete concatenated interleaved coded modulated data sample block D _total = [d ₀ ,d ₁ ,...,d _K-2 ,d _K-1 ];

4) Each multimedia broadcasting anti-fading wireless signal transmitter in the single frequency network demultiplexes the data sample blocks modulated by space-frequency modulation time-domain discrete concatenated interleaving coding and modulates them according to each space-frequency modulation time-domain discrete cascading interleaving coding modulation Sequential parity of the data samples is sequentially separated to generate space-frequency modulation time-domain discrete concatenated interleaved coding modulation data sample odd sub-block _Dodd =[d ₀ , d ₂ ,..., d _K-4 , d _K-2 ] and Space-frequency modulation time-domain discrete concatenated interleaving coding modulation data sample even sub-block D _even = [d ₁ , d ₃ ,..., d _K-3 , d _K-1 ];

生成模式3为生成模式4为

生成模式5为

生成模式6为生成模式7为D_new＝[D^* _奇，D_偶]，生成模式8为

生成模式9为

生成模式10为

生成模式11为

生成模式12为生成模式13为D_new＝[D_奇，D^* _偶]，生成模式14为

生成模式15为

生成模式16为

生成模式17为

生成模式18为

比较18种生成模式合成的空频调制时域离散级联交织编码调制数据样值块D_new，选取其中具有最低峰均功率比的降峰均功率比空频调制时域离散级联交织编码调制数据样值块

并将降峰均功率比空频调制时域离散级联交织编码调制数据样值块

所对应采用的生成模式信息发送给业务指标序列设置单元，其中，D^* _奇表示对空频调制时域离散级联交织编码调制数据样值奇子块D_奇的各空频调制时域离散级联交织编码调制数据样值进行共轭运算处理而得到的空频调制时域离散级联交织编码调制数据样值子块；D^* _偶表示对空频调制时域离散级联交织编码调制数据样值偶子块D_偶的各空频调制时域离散级联交织编码调制数据样值进行共轭运算处理而得到的空频调制时域离散级联交织编码调制数据样值子块；5) Each multimedia broadcast anti-fading wireless signal transmitter in the single frequency network uses the peak-to-average power ratio adjustment unit to discretely concatenate and interleave coded and modulated data sample odd sub-block D _odd for space-frequency modulation and time-domain discrete for space-frequency modulation The concatenated interleaved coded modulation data sample block _Deven performs signal power adjustment and corresponding signal processing and recomposes a new space-frequency modulation time-domain discrete cascaded interleaved coded modulated data sample block D _new , when the new space-frequency modulation The domain discrete concatenated interleaved coded modulation data sample block D _new is obtained by the following generation mode, the generation mode 1 is D _new = [D _odd , D _even ], and the generation mode 2 is

Generate schema 3 as Generate schema 4 as

Generate schema 5 as

Generate schema 6 as Generation mode 7 is D _new = [D ^* _odd , D _even ], generation mode 8 is

Generate schema 9 as

Generate schema 10 as

Generate schema 11 as

Generate schema 12 as Generation mode 13 is D _new = [D _odd , D ^* _even ], generation mode 14 is

Generate schema 15 as

Generate schema 16 as

Generate schema 17 as

Generate schema 18 as

Comparing the space-frequency modulation time-domain discrete concatenated interleaving coded modulation data block D _new synthesized by 18 generation modes, and selecting the one with the lowest peak-to-average power ratio with reduced peak-to-average power ratio data sample block

And reduce the peak-to-average power ratio space-frequency modulation time-domain discrete concatenated interleaved coded modulation data sample block

The generated mode information correspondingly adopted is sent to the service index sequence setting unit, wherein, D ^* _odd represents each space-frequency modulation time-domain discrete level for the space-frequency modulation time-domain discrete concatenated interleaved coded modulation data sample odd sub-block D _odd The space-frequency modulated time-domain discrete concatenated interleaved coded modulated data sample sub ^- block obtained by _conjugating the interleaved coded modulated data samples; The space-frequency modulated time _-domain discrete concatenated interleaving coded modulation data sample sub-block obtained by performing conjugate operation processing on each space-frequency modulated time-domain discrete concatenated interleaved coded modulated data sample value of the value even sub-block Deven;

6) Each multimedia broadcast anti-fading wireless signal transmitter in the single frequency network inserts a service index sequence after the training sequence to form a discrete sample block of the time domain training sequence in the time domain. The service index sequence contains and uniquely expresses the single frequency network Each system parameter and business mode information of each multimedia broadcasting anti-fading wireless signal transmitter;

7) Each multimedia broadcast anti-fading wireless signal transmitter in the single frequency network inserts the cyclic prefix as a guard interval into the reduced peak-to-average power ratio space-frequency modulation time-domain discrete concatenated interleaved coded modulation data sample block to form a reduced peak-to-average power ratio Space-frequency modulated time-domain cyclic prefix discrete concatenated interleaved coded modulation data sample block, as the frame body, the length of the cyclic prefix is C;

8) Each multimedia broadcasting anti-fading wireless signal transmitter in the single frequency network inserts the time-domain training sequence discrete sample block, that is, the frame header, into the peak-to-average power ratio space-frequency modulation time-domain cyclic prefix discrete concatenated interleaving coded modulation data sample The value block is the frame body to form a signal frame;

9) Each multimedia broadcast anti-fading wireless signal transmitter in the single frequency network adopts a square root raised cosine roll-off filter to shape the signal pulse of the signal frame;

10) Each multimedia broadcast anti-fading wireless signal transmitter in the single frequency network up-converts the baseband signal to the carrier.

According to the embodiment of the transmitter signal framing modulation of the multimedia broadcast single frequency network anti-fading wireless signal framing modulation method of the present invention, as shown in Figure 2, the specific implementation is as follows:

The network data manager of the single frequency network forms an FFT concatenated interleaved coded modulation data block in the frequency domain through RS coding, convolutional interleaving, LDPC coding, symbol modulation, and symbol interleaving of the input data bit stream; the coding rate of LDPC code One of 1/4, 1/2, 5/8, 3/4 and 7/8; symbol modulation is one of QPSK, 16QAM, 32QAM, 64QAM, 64APSK, 256APSK, 1024APSK, symbol constellation diagram The mapping method adopts Gray code mapping; the symbol interleaving adopts the random interleaving method; the space-frequency encoder with a code rate of 1 is used to modulate the FFT concatenated interleaving code modulation data block formed in the frequency domain to each multimedia broadcasting in the single frequency network The anti-fading wireless signal transmitter branch forms a space-frequency modulation FFT cascade interleaving coded modulation data block, and adjusts the time synchronization of each multimedia broadcasting single frequency network anti-fading wireless signal transmitter branch to ensure that all transmitters in the network are in At the same time, the space-frequency modulation FFT concatenated interleaved coded modulation data block is processed; then it is transformed into a space-frequency modulated time-domain discrete concatenated interleaved coded modulated data sample block by IFFT, which is generated and selected by the peak-to-average power ratio adjustment unit Among them, the reduced peak-to-average power ratio with the lowest peak-to-average power ratio space-frequency modulation time-domain discrete concatenated interleaved coded modulation data sample block simultaneously sends the corresponding generated mode information to the service index sequence setting unit.

The FFT concatenated interleaving coding modulation data block of each multimedia broadcasting anti-fading wireless signal transmitter in the single frequency network is composed of subcarriers, and the frequency interval of the subcarriers is one of 2KHz, 4KHz, and 1KHz.

The training sequence of each multimedia broadcast anti-fading wireless signal transmitter in the single frequency network is made up of the first training sequence and the second training sequence; Each symbol is alternately inserted into a new sequence and a cyclic prefix of length G; the second training sequence is generated by alternately inserting each symbol of the constant envelope zero autocorrelation CAZAC sequence-B ^* and the pseudo-random PN sequence A ^* The new sequence and its cyclic prefix whose length is G; B ^* means to perform conjugate operation processing on each symbol of B, and A ^* means to perform conjugate operation processing on each symbol of A, and B and A have the same symbol length L: the cyclic prefix length G of the first training sequence and the second training sequence is 1/8 of the symbol length L of the first training sequence and the second training sequence.

Each multimedia broadcast anti-fading wireless signal transmitter in the single frequency network inserts a service index sequence after the training sequence to form a discrete sample block of the time domain training sequence in the time domain.

The service index sequence of each multimedia broadcast anti-fading wireless signal transmitter in the single frequency network has pseudo-random characteristics, and is realized by a set of shifted m sequences; each multimedia broadcast anti-fading wireless signal transmitter in the single frequency network has different The service index sequence contains and uniquely expresses the system parameters and service mode information of each multimedia broadcast anti-fading wireless signal transmitter in the single frequency network.

Each multimedia broadcast anti-fading wireless signal transmitter in the single frequency network inserts the cyclic prefix as a guard interval into the peak-to-average power ratio space-frequency modulation time-domain discrete cascaded interleaving code modulation data sample block to form a peak-to-average power ratio space-frequency Modulate time-domain cyclic prefix discrete concatenated interleaved coding modulation data sample block, as the frame body, the length of the cyclic prefix is C; each multimedia broadcast anti-fading wireless signal transmitter in the single frequency network will time-domain training sequence discrete sample block That is, the frame header is inserted into the time-domain cyclic prefix of the reduced peak-to-average power ratio space-frequency modulation, the discrete concatenated interleaved coded modulation data sample block, that is, the frame body, to form a signal frame; each multimedia broadcast anti-fading wireless signal transmitter in the single frequency network The cyclic prefix length C of the signal frame is 1/16 of the length K of the FFT concatenated interleaving coded modulation data block.

Each multimedia broadcast anti-fading wireless signal transmitter in the single frequency network uses a square root raised cosine roll-off filter to perform pulse shaping on the signal of the signal frame.

The specific embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments, and those skilled in the art can make various modifications without departing from the spirit and scope of the claims of the application modify or remodel.

Claims (6)

1. an anti-fading wireless signal framing modulation method of multimedia broadcasting single frequency network, is characterized in that it comprises the following steps:

1) flow through RS coding, convolutional interleave, LDPC coding, code element modulation, symbol interleave of input data bit on frequency domain, formed the cascade interweaved coding modulation data piece of FFT by the network data management device of single frequency network, RS represents Reed-Solomon, LDPC represents Low Density Parity Check, the length of the cascade interweaved coding modulation data piece of FFT is K, and the numerical value of K is got even number;

2) to adopt code check be 1 to the network data management device of single frequency network that space-frequency coding device is modulated to cascade interweaved the FFT forming on frequency domain coding modulation data piece on each multimedia broadcasting anti-fading wireless signal transmitter branch road in single frequency network and forms the cascade interweaved coding modulation data piece of empty frequency modulation FFT processed, and the time synchronized of adjusting each multimedia broadcasting single-frequency network anti-fading wireless signal transmitter branch road is all processed the cascade interweaved coding modulation data piece of empty frequency modulation FFT processed at one time with all transmitters in assurance network;

3) each multimedia broadcasting anti-fading wireless signal transmitter in single frequency network adopts IFFT that cascade interweaved FFT processed empty frequency modulation coding modulation data piece is transformed to the cascade interweaved coding modulation data sample value of sky frequency modulation time domain discrete processed piece D _total=[d ₀, d ₁..., d _k-2, d _k-1];

4) each multimedia broadcasting anti-fading wireless signal transmitter in single frequency network separates successively and generates the strange sub-block D of the cascade interweaved coding modulation data sample value of empty frequency modulation time domain discrete processed by time domain discrete processed empty frequency modulation cascade interweaved coding modulation data sample value piece demultiplexing and according to the sequencing odd even of the cascade interweaved coding modulation data sample value of each empty frequency modulation time domain discrete processed _very=[d ₀, d ₂..., d _k-4, d _k-2] and the even sub-block D of the cascade interweaved coding modulation data sample value of empty frequency modulation time domain discrete processed _even=[d ₁, d ₃..., d _k-3, d _k-1];

5) each multimedia broadcasting anti-fading wireless signal transmitter in single frequency network passes through peak-to-average power ratio adjustment unit to the strange sub-block D of the cascade interweaved coding modulation data sample value of empty frequency modulation time domain discrete processed _very, the even sub-block D of the cascade interweaved coding modulation data sample value of empty frequency modulation time domain discrete processed _evencarry out signal power adjustment and corresponding signal and process also the synthetic new cascade interweaved coding modulation data sample value of empty frequency modulation time domain discrete processed piece D again _new, the new cascade interweaved coding modulation data sample value of empty frequency modulation time domain discrete processed piece D _newadopt following generate pattern to obtain, generate pattern 1 is D _new=[D _very, D _even], generate pattern 2 is

generate pattern 3 is generate pattern 4 is

generate pattern 5 is generate pattern 6 is

generate pattern 7 is D _new=[D ^* _very, D _even], generate pattern 8 is

generate pattern 9 is

generate pattern 10 is

generate pattern 11 is

generate pattern 12 is

generate pattern 13 is D _new=[D _very, D ^* _even], generate pattern 14 is

generate pattern 15 is

generate pattern 16 is

generate pattern 17 is

generate pattern 18 is

the relatively 18 kinds of cascade interweaved coding modulation data sample value of empty frequency modulation time domain discrete processed piece D that generate pattern is synthetic _new, choose wherein there is minimum peak-to-average power ratio the cascade interweaved coding modulation data sample value of the empty frequency modulation time domain discrete processed of peak-to-average power ratio piece falls

and the cascade interweaved coding modulation data sample value of the empty frequency modulation time domain discrete processed of peak-to-average power ratio piece will fall

the corresponding generate pattern information adopting send to operational indicator sequence setting unit, wherein, D ^* _veryrepresent the strange sub-block D of the cascade interweaved coding modulation data sample value of empty frequency modulation time domain discrete processed _verythe cascade interweaved coding modulation data sample value of each empty frequency modulation time domain discrete processed carry out conjugate operation processing and the cascade interweaved coding modulation data sample value of the empty frequency modulation time domain discrete processed sub-block that obtains; D ^* _evenrepresent the even sub-block D of the cascade interweaved coding modulation data sample value of empty frequency modulation time domain discrete processed _eventhe cascade interweaved coding modulation data sample value of each empty frequency modulation time domain discrete processed carry out conjugate operation processing and the cascade interweaved coding modulation data sample value of the empty frequency modulation time domain discrete processed sub-block that obtains;

6) each multimedia broadcasting anti-fading wireless signal transmitter Insert service index series after training sequence in single frequency network forms time-domain training sequence discrete sample block in time domain, and operational indicator sequence is comprising and unique each system parameters and business model information of expressing each multimedia broadcasting anti-fading wireless signal transmitter in single frequency network;

7) each multimedia broadcasting anti-fading wireless signal transmitter in single frequency network inserts using Cyclic Prefix as protection interval and falls the cascade interweaved coding modulation data sample value of the empty frequency modulation time domain discrete processed of peak-to-average power ratio piece, the discrete cascade interweaving encoding of the empty frequency modulation time domain cyclic prefix processed of peak-to-average power ratio modulating data sample value piece falls in formation, as frame, the length of Cyclic Prefix is C;

8) each multimedia broadcasting anti-fading wireless signal transmitter in single frequency network is that frame head is inserted into that to fall the discrete cascade interweaving encoding of the empty frequency modulation time domain cyclic prefix processed of peak-to-average power ratio modulating data sample value piece be frame by time-domain training sequence discrete sample block, to form signal frame;

9) each multimedia broadcasting anti-fading wireless signal transmitter in single frequency network adopts square root raised cosine filter to be shaped to the signal pulse of signal frame;

10) each multimedia broadcasting anti-fading wireless signal transmitter in single frequency network by baseband signal up-conversion to carrier wave.

2. by the anti-fading wireless signal framing modulation method of multimedia broadcasting single frequency network of claim 1, it is characterized in that: described training sequence is made up of the first training sequence and the second training sequence; The Cyclic Prefix that the first training sequence is G by each symbol new sequence that alternately insertion produces and the length thereof of permanent envelope zero auto-correlation CAZAC sequence B and pseudorandom PN sequence A forms; The second training sequence is by permanent envelope zero auto-correlation CAZAC sequence-B ^*with pseudorandom PN sequence A ^*each symbol alternately insert the Cyclic Prefix composition that the new sequence that produces and length thereof are G; B ^*represent each symbol of B to carry out conjugate operation processing, A ^*represent each symbol of A to carry out conjugate operation processing, B has identical symbol lengths L with A.

3. by the anti-fading wireless signal framing modulation method of multimedia broadcasting single frequency network of claim 1, it is characterized in that: described C gets 1/16 of K; The encoding rate of LDPC coding is in 1/4,1/2,5/8,3/4 and 7/8; Code element is modulated to the one in QPSK, 16QAM, 32QAM, 64QAM, 64APSK, 256APSK, 1024APSK, and symbol constellations figure mapping mode adopts Gray code mapping; Symbol interleave adopts random interleaving mode.

4. by the anti-fading wireless signal framing modulation method of multimedia broadcasting single frequency network of claim 1, it is characterized in that: described operational indicator sequence has pseudo-random characteristics, realized by one group of Phase shift m sequence.

5. by the anti-fading wireless signal framing modulation method of multimedia broadcasting single frequency network of claim 1, it is characterized in that: the cascade interweaved coding modulation data piece of described FFT is made up of subcarrier, and the frequency interval of subcarrier is got the one in 2KHz, 4KHz, 1KHz.

6. by the anti-fading wireless signal framing modulation method of multimedia broadcasting single frequency network of claim 1, it is characterized in that: described G gets 1/8 of L.

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