CN102263751B - Single-frequency-network anti-noise mobile digital broadcast signal transmission method - Google Patents

Abstract

The invention discloses a single frequency network anti-noise mobile digital broadcasting signal transmission method, which is a mixed transmission scheme of time domain, frequency domain and space domain. The single frequency network anti-noise mobile digital broadcast signal transmission method of the invention has the advantages of low peak-to-average power ratio, short synchronization time, anti-noise, controllable multi-service and the like.

Description

A single frequency network anti-noise mobile digital broadcasting signal transmission method

technical field

The invention belongs to the field of mobile communication, and more specifically relates to a single frequency network anti-noise mobile digital broadcasting signal transmission method.

Background technique

Because OFDM multi-carrier transmission technology has many advantages such as simple structure, high spectrum utilization rate, and resistance to frequency selectivity and channel time variation, it has attracted much attention and has been deeply researched and applied in Xdsl, broadband mobile communication, broadband mobile local area network, It is widely used in many fields such as digital TV, mobile digital broadcasting, etc. 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.

Channel coding is an important part of digital communication systems. With the rapid development of modern information technology, channel coding technology has become an indispensable technology in the field of modern communication. Redundant code elements are embedded in the information sequence, and channel coding technology reduces signal errors during transmission through the role of redundant code elements, thereby improving the reliability of the communication system. Low Density Parity Check (Low Density Parity Check, LDPC) code is an error correction code used to transmit information in a noisy transmission channel and perform forward error correction (FEC, Forward Error Correction). LDPC coding is a coding scheme that can make the data transmission rate close to the theoretical maximum, which is the Shannon limit.

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 spectrum utilization of the digital TV mobile digital broadcasting transmission system . In the actual single frequency network communication environment, the performance of the digital TV mobile digital broadcasting communication system is affected by factors such as synchronization time, clock jitter, channel fading, and channel interference. The single frequency network anti-noise mobile digital broadcasting signal transmitter transmission method is the key technology to realize the reliable digital television single frequency network anti-noise mobile digital broadcasting.

Using digital TV single frequency network anti-noise mobile digital broadcasting transmission system to provide controllable multi-services such as free TV broadcasting, paid TV broadcasting, confidential information transmission, multimedia value-added services, etc. is the embodiment of the new generation of digital TV mobile digital broadcasting transmission system to meet social needs.

Based on the above background, the present invention proposes a single frequency network anti-noise mobile digital broadcast signal transmission method for the actual communication environment, which can meet the needs of high data rate controllable multi-service digital television single frequency network anti-noise mobile digital broadcast transmission.

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.Whi taker, 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, J 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.

Z.Li, L.Chen, L.Zeng, S.Lin, W.Fong, "Efficient encoding of quasi-cycliclow-density parity-check codes," IEEE Trans.Commun., vol.54, no.1, pp .71-81, Jan. 2006.

Contents of the invention

Aiming at the problem of high coding data rate controllable multi-service digital TV single frequency network anti-noise mobile digital broadcasting, the invention proposes a single frequency network anti-noise mobile digital broadcasting signal transmission method.

A kind of single frequency network anti-noise mobile digital broadcasting signal transmission method that the present invention proposes is characterized in that it comprises the following steps:

1) The central data manager of the single frequency network converts the multimedia data stream into a bit stream through the media data processor, and uses the scrambling code sequence generated by the feedback shift register to perform scrambling processing to form an input data bit stream;

2) The network data manager of the single frequency network forms an FFT encoded data block in the frequency domain after the input data bit stream undergoes LDPC encoding, symbol modulation and symbol rotation. LDPC means low-density parity check, and FFT means fast discrete Fourier Transformation, the length of the FFT coded data block is K; the symbol modulation is one of QPSK, 16QAM, 64QAM and 256QAM, and the symbol constellation mapping method of symbol modulation adopts Gray code mapping; the symbol rotation is through the symbol constellation The rotation angle of the symbol constellation diagram of QPSK is 22.5 degrees, the rotation angle of the symbol constellation diagram of 16QAM is 11.25 degrees, the rotation angle of the symbol constellation diagram of 64QAM is 5.626 degrees, and the rotation angle of the symbol constellation diagram of 256QAM The angle is 2.8125 degrees;

3) The network data manager of the single frequency network uses a space-frequency coder with a code rate of 1 to modulate the FFT coded data block formed in the frequency domain to each anti-noise mobile digital broadcasting signal transmitter branch in the single frequency network to form Space-frequency modulation FFT coded data blocks, and adjust the time synchronization of each anti-noise mobile digital broadcast signal transmitter branch to ensure that all transmitters in the network process the space-frequency modulated FFT coded data blocks at the same time;

4) Each anti-noise mobile digital broadcasting signal transmitter in the single frequency network uses IFFT to transform the space-frequency modulation FFT coded data block into a space-frequency modulation time-domain discrete coded data sample block D _total , and IFFT means inverse fast discrete Fourier transform;

5) Each anti-noise mobile digital broadcast signal transmitter in the single frequency network divides the space-frequency modulation time-domain discretely coded data sample block into two equally in sequence, and the space-frequency modulation time-domain discretely coded data sample sub-blocks _D1 and Space frequency modulation time domain discrete coded data sample sub-block D ₂ , D _total = [D ₁ , D ₂ ];

并将降峰均功率比空频调制时域离散编码数据样值块

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^* ₁表示对空频调制时域离散编码数据样值子块D₁的各空频调制时域离散编码数据样值进行共轭运算处理而得到的空频调制时域离散编码数据样值子块；6) Each anti-noise mobile digital broadcasting signal transmitter in the single frequency network uses the peak-to-average power ratio adjustment unit for the space-frequency modulation time-domain discrete coding data sample sub-block D ₁ , the space-frequency modulation time-domain discrete coding data sample sub-block D 1 Block D ₂ performs signal addition, subtraction, and conjugate operation processing and re-synthesizes a new space-frequency modulation time-domain discrete-coded data sample block _Dnew , and the new space-frequency modulation time-domain discrete-coded data sample block _Dnew is generated as follows The mode is obtained, the generation mode 1 is D _new = [D ₁ , D ₂ ], and the generation mode 2 is ${\mathrm{D.}}_{\mathrm{new}}=[{\mathrm{D.}}_1,\sqrt{1/2}({\mathrm{D.}}_1+{\mathrm{D.}}_2)],$ Generate schema 3 as ${\mathrm{D.}}_{\mathrm{new}}=[{\mathrm{D.}}_1,\sqrt{1/2}({\mathrm{D.}}_1-{\mathrm{D.}}_2)],$ Generate schema 4 as ${\mathrm{D.}}_{\mathrm{new}}=[\sqrt{1/2}({\mathrm{D.}}_1+{\mathrm{D.}}_2),{\mathrm{D.}}_2],$ Generate schema 5 as ${\mathrm{D.}}_{\mathrm{new}}=[\sqrt{1/2}({\mathrm{D.}}_1-{\mathrm{D.}}_2),{\mathrm{D.}}_2],$ Generate schema 6 as ${\mathrm{D.}}_{\mathrm{new}}=[\sqrt{1/2}({\mathrm{D.}}_1+{\mathrm{D.}}_2),\sqrt{1/2}({\mathrm{D.}}_1-{\mathrm{D.}}_2)],$ Generation mode 7 is D _new = [D ^* ₁ , D ₂ ], generation mode 8 is ${\mathrm{D.}}_{\mathrm{new}}=[{{\mathrm{D.}}^{*}}_1,\sqrt{1/2}({{\mathrm{D.}}^{*}}_1+{\mathrm{D.}}_2)],$ Generate schema 9 as ${\mathrm{D.}}_{\mathrm{new}}=[{{\mathrm{D.}}^{*}}_1,\sqrt{1/2}({{\mathrm{D.}}^{*}}_1-{\mathrm{D.}}_2)],$ Generate schema 10 as ${\mathrm{D.}}_{\mathrm{new}}=[\sqrt{1/2}({{\mathrm{D.}}^{*}}_1+{\mathrm{D.}}_2),{\mathrm{D.}}_2],$ Generate schema 11 as ${\mathrm{D.}}_{\mathrm{new}}=[\sqrt{1/2}({{\mathrm{D.}}^{*}}_1-{\mathrm{D.}}_2),{\mathrm{D.}}_2],$ Generate schema 12 as ${\mathrm{D.}}_{\mathrm{new}}=[\sqrt{1/2}({{\mathrm{D.}}^{*}}_1+{\mathrm{D.}}_2),\sqrt{1/2}({{\mathrm{D.}}^{*}}_1-{\mathrm{D.}}_2)],$ Compare the space-frequency modulation time-domain discrete-coded data sample block D _new synthesized by 12 generation modes, and select the space-frequency modulation time-domain discrete-coded data sample block with the lowest peak-to-average power ratio among them

and reduce the peak-to-average power ratio to the space-frequency modulation time-domain discretely coded data sample block

The generated mode information correspondingly adopted is sent to the service index sequence setting unit, wherein, D ^* ₁ means that each space-frequency modulation time-domain discrete-coded data sample value of the space-frequency modulation time-domain discrete-coded data sample sub-block D ₁ is shared Space-frequency modulated time-domain discretely coded data sample sub-blocks obtained through yoke operation processing;

7) Each anti-noise mobile digital broadcasting signal transmitter in the single frequency network uses the training sequence as the real part sequence of the complex training sequence, and uses the service index sequence set by the service index sequence setting unit as the imaginary part sequence of the complex training sequence. In the time domain, the discrete sample blocks that constitute the complex training sequence, the length of the training sequence, the service index sequence, and the discrete sample block of the complex training sequence are all X, and the service index sequence contains and uniquely expresses each resistance in the single frequency network. Various system parameters and business mode information of the noise mobile digital broadcasting signal transmitter;

8) Each anti-noise mobile digital broadcast signal transmitter in the single frequency network repeats the discrete sample value block of the complex training sequence formed on the time domain continuously for 4 times in the time domain to form a time domain embedded training sequence discrete sample value block, The length of the time-domain embedding training sequence discrete sample block is equal to the length of the peak-to-average power ratio space-frequency modulation time-domain discrete-coded data sample block in value, that is, K=4×X;

9) Each anti-noise mobile digital broadcast signal transmitter in the single frequency network directly superimposes the time-domain discrete coded data sample blocks and the time-domain embedded training sequence discrete sample blocks to form the time-domain embedded training Sequential reduced peak-to-average power ratio space-frequency modulation time-domain discretely coded data sample block, as a frame body;

10) Each anti-noise mobile digital broadcast signal transmitter in the single frequency network uses the cyclic prefix as a guard interval, that is, the frame header is inserted into the training sequence in the time domain, and the peak-to-average power ratio is reduced by space-frequency modulation. The time-domain discretely encoded data sample block is the frame body , to form a signal frame, the length of the cyclic prefix is C;

11) Each anti-noise mobile digital broadcast 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;

12) Each anti-noise mobile digital broadcast signal transmitter in the single frequency network up-converts the baseband signal to the carrier to form a radio frequency signal and transmit it to the wireless channel in the air;

13) The anti-noise mobile digital broadcast signal receiver in the single frequency network detects and receives the radio frequency signal sent by each anti-noise mobile digital broadcast signal transmitter in the single frequency network and converts it down to form a baseband signal, and utilizes the cycle of the signal frame Prefix characteristics and structural characteristics of the signal frame are used for baseband signal reception processing.

According to the above-mentioned single frequency network anti-noise mobile digital broadcast signal transmission method, it is characterized in that: the peak-to-average power ratio of each anti-noise mobile digital broadcast signal transmitter in the single frequency network The time-domain discrete coded data sample sub-blocks of space-frequency modulation are recombined through signal addition, subtraction, and conjugate operation processing of 12 specific generation modes; each anti-noise mobile digital broadcasting signal transmitter in the single frequency network There are periodic time domain embedded training sequence discrete sample blocks in the signal frame; the length X of the training sequence of each anti-noise mobile digital broadcasting signal transmitter in the single frequency network is one of 512, 1024, 2048, and the corresponding The lengths K of space-frequency modulation FFT coded data blocks are 2048, 4096, and 8192 respectively, and the frequency intervals of corresponding subcarriers are 4KHz, 2KHz, and 1KHz respectively, and the corresponding cyclic prefix lengths C are respectively space-frequency modulation FFT coded data blocks The length K is 1/4, 1/8, 1/16; the training sequence and service index sequence of each anti-noise mobile digital broadcast signal transmitter in the single frequency network are composed of a series of 1 or -1, with pseudo-random Characteristics; the training sequences and service index sequences of each anti-noise mobile digital broadcasting signal transmitter in the single frequency network are orthogonal to each other; the different services of each anti-noise mobile digital broadcasting signal transmitter in the single frequency network The index sequence contains and uniquely expresses the system parameters and service mode information of each anti-noise mobile digital broadcasting signal transmitter in the single frequency network; the code rate of the space frequency coder is 1. The anti-noise mobile digital broadcast signal receiver in the single frequency network can make full use of the cyclic prefix characteristics of the signal frame and the structural characteristics of the signal frame to perform baseband signal reception processing, including the time-frequency domain joint iteration of the signal frame header and signal frame body Separate processing.

Features of the present invention:

The present invention is a mixed transmission scheme of time domain, frequency domain and space domain. The generation mode of the time-domain discrete-coded data sample block with reduced peak-to-average power ratio and space-frequency modulation of the present invention and the selection method of the reduced-peak-to-average power ratio space-frequency modulated time-domain discrete-coded data sample block with the lowest peak-to-average power ratio not only The maximum peak power of the OFDM signal can be fully utilized, 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 Rayleigh distribution. , the amount of additional information required for the adopted generation mode is small, and it is easy to process and recover the original signal of the OFDM signal at the receiver, and at the same time, it will not destroy the orthogonality characteristics of the subcarrier signal and will not generate additional nonlinear distortion. In the signal frame of each anti-noise mobile digital broadcast signal transmitter in the single frequency network, there are periodic time domain embedded training sequence discrete sample blocks, and the training sequence of each anti-noise mobile digital broadcast signal transmitter in the single frequency network, The service index sequence has pseudo-random characteristics. The training sequence and service index sequence of each anti-noise mobile digital broadcasting signal transmitter in the single frequency network are orthogonal to each other. The anti-noise mobile digital broadcasting signal transmission in the single frequency network The time-domain embedding training sequence of the machine is reduced peak-to-average power ratio space-frequency modulation time-domain discrete coded data sample block is composed of the reduced peak-to-average power ratio space-frequency modulation time-domain discrete coded data sample block and the time-domain embedded training sequence discrete sample value These are formed by direct superimposition of blocks, which ensure that each mobile digital broadcast signal receiver in the single frequency network can achieve fast and accurate frame synchronization, frequency synchronization, time synchronization, channel transmission characteristic estimation, and phase noise and channel transmission characteristics. Reliable tracking. Inserting the cyclic prefix as a guard interval into the time-domain embedding training sequence to reduce the peak-to-average power ratio space-frequency modulation time-domain discretely coded data sample blocks to form a signal frame can reduce the interference between adjacent signal frames. Channel coding the input data with LDPC codes provides error correction performance close to the Shannon limit. Symbol modulation and constellation rotation provide diversity effects for mobile digital broadcasting signals. Each different service index sequence of each anti-noise mobile digital broadcasting signal transmitter in the single frequency network contains and uniquely expresses each system parameter and business mode information of each anti-noise mobile digital broadcasting signal transmitter in the single frequency network, The anti-noise mobile digital broadcast transmission system of the digital TV single frequency network can 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 transmission method of the present invention has the advantages of low peak-to-average power ratio, short synchronization time, small clock jitter, anti-channel fading, anti-channel interference, can provide high data rate controllable multi-service digital TV single frequency network anti-noise mobile digital broadcast transmission and many other advantages advantage.

Description of drawings

Fig. 1 is a schematic diagram of an embodiment of signal transmission between a transmitter and a receiver of a single frequency network anti-noise mobile digital broadcasting signal transmission method according to the present invention.

Fig. 2 is a schematic diagram of an embodiment of signal frame formation during the signal transmission process between the transmitter and the receiver of the single frequency network anti-noise mobile digital broadcasting signal transmission method 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 signal transmission between the transmitter and the receiver of the single frequency network anti-noise mobile digital broadcasting signal transmission method proposed by the present invention (assuming that there are N transmitters in the single frequency network), as shown in Figure 1, follow the steps conduct:

1) The central data manager of the single frequency network converts the multimedia data stream into a bit stream through the media data processor, and uses the scrambling code sequence generated by the feedback shift register to perform scrambling processing to form an input data bit stream;

2) The network data manager of the single frequency network forms an FFT encoded data block in the frequency domain after the input data bit stream undergoes LDPC encoding, symbol modulation and symbol rotation. LDPC means low-density parity check, and FFT means fast discrete Fourier Transformation, the length of the FFT coded data block is K; the symbol modulation is one of QPSK, 16QAM, 64QAM and 256QAM, and the symbol constellation mapping method of symbol modulation adopts Gray code mapping; the symbol rotation is through the symbol constellation The rotation angle of the symbol constellation diagram of QPSK is 22.5 degrees, the rotation angle of the symbol constellation diagram of 16QAM is 11.25 degrees, the rotation angle of the symbol constellation diagram of 64QAM is 5.626 degrees, and the rotation angle of the symbol constellation diagram of 256QAM The angle is 2.8125 degrees;

3) The network data manager of the single frequency network uses a space-frequency coder with a code rate of 1 to modulate the FFT coded data block formed in the frequency domain to each anti-noise mobile digital broadcasting signal transmitter branch in the single frequency network to form Space-frequency modulation FFT coded data blocks, and adjust the time synchronization of each anti-noise mobile digital broadcast signal transmitter branch to ensure that all transmitters in the network process the space-frequency modulated FFT coded data blocks at the same time;

4) Each anti-noise mobile digital broadcasting signal transmitter in the single frequency network uses IFFT to transform the space-frequency modulation FFT coded data block into a space-frequency modulation time-domain discrete coded data sample block D _total , and IFFT means inverse fast discrete Fourier transform;

5) Each anti-noise mobile digital broadcast signal transmitter in the single frequency network divides the space-frequency modulation time-domain discretely coded data sample block into two equally in sequence, and the space-frequency modulation time-domain discretely coded data sample sub-blocks _D1 and Space frequency modulation time domain discrete coded data sample sub-block D ₂ , D _total = [D ₁ , D ₂ ];

并将降峰均功率比空频调制时域离散编码数据样值块

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^* ₁表示对空频调制时域离散编码数据样值子块D₁的各空频调制时域离散编码数据样值进行共轭运算处理而得到的空频调制时域离散编码数据样值子块；6) Each anti-noise mobile digital broadcasting signal transmitter in the single frequency network uses the peak-to-average power ratio adjustment unit for the space-frequency modulation time-domain discrete coding data sample sub-block D ₁ , the space-frequency modulation time-domain discrete coding data sample sub-block D 1 Block D ₂ performs signal addition, subtraction, and conjugate operation processing and re-synthesizes a new space-frequency modulation time-domain discrete-coded data sample block _Dnew , and the new space-frequency modulation time-domain discrete-coded data sample block _Dnew is generated as follows The mode is obtained, the generation mode 1 is D _new = [D ₁ , D ₂ ], and the generation mode 2 is ${\mathrm{D.}}_{\mathrm{new}}=[{\mathrm{D.}}_1,\sqrt{1/2}({\mathrm{D.}}_1+{\mathrm{D.}}_2)],$ Generate schema 3 as ${\mathrm{D.}}_{\mathrm{new}}=[{\mathrm{D.}}_1,\sqrt{1/2}({\mathrm{D.}}_1-{\mathrm{D.}}_2)],$ Generate schema 4 as ${\mathrm{D.}}_{\mathrm{new}}=[\sqrt{1/2}({\mathrm{D.}}_1+{\mathrm{D.}}_2),{\mathrm{D.}}_2],$ Generate schema 5 as ${\mathrm{D.}}_{\mathrm{new}}=[\sqrt{1/2}({\mathrm{D.}}_1-{\mathrm{D.}}_2),{\mathrm{D.}}_2],$ Generate schema 6 as ${\mathrm{D.}}_{\mathrm{new}}=[\sqrt{1/2}({\mathrm{D.}}_1+{\mathrm{D.}}_2),\sqrt{1/2}({\mathrm{D.}}_1-{\mathrm{D.}}_2)],$ Generation mode 7 is D _new = [D ^* ₁ , D ₂ ], generation mode 8 is ${\mathrm{D.}}_{\mathrm{new}}=[{{\mathrm{D.}}^{*}}_1,\sqrt{1/2}({{\mathrm{D.}}^{*}}_1+{\mathrm{D.}}_2)],$ Generate schema 9 as ${\mathrm{D.}}_{\mathrm{new}}=[{{\mathrm{D.}}^{*}}_1,\sqrt{1/2}({{\mathrm{D.}}^{*}}_1-{\mathrm{D.}}_2)],$ Generate schema 10 as ${\mathrm{D.}}_{\mathrm{new}}=[\sqrt{1/2}({{\mathrm{D.}}^{*}}_1+{\mathrm{D.}}_2),{\mathrm{D.}}_2],$ Generate schema 11 as ${\mathrm{D.}}_{\mathrm{new}}=[\sqrt{1/2}({{\mathrm{D.}}^{*}}_1-{\mathrm{D.}}_2),{\mathrm{D.}}_2],$ Generate schema 12 as ${\mathrm{D.}}_{\mathrm{new}}=[\sqrt{1/2}({{\mathrm{D.}}^{*}}_1+{\mathrm{D.}}_2),\sqrt{1/2}({{\mathrm{D.}}^{*}}_1-{\mathrm{D.}}_2)],$ Compare the space-frequency modulation time-domain discrete-coded data sample block D _new synthesized by 12 generation modes, and select the space-frequency modulation time-domain discrete-coded data sample block with the lowest peak-to-average power ratio among them

and reduce the peak-to-average power ratio to the space-frequency modulation time-domain discretely coded data sample block

The generated mode information correspondingly adopted is sent to the service index sequence setting unit, wherein, D ^* ₁ means that each space-frequency modulation time-domain discrete-coded data sample of the space-frequency modulation time-domain discrete-coded data sample sub-block D ₁ is shared Space-frequency modulated time-domain discretely coded data sample sub-blocks obtained through yoke operation processing;

7) Each anti-noise mobile digital broadcasting signal transmitter in the single frequency network uses the training sequence as the real part sequence of the complex training sequence, and uses the service index sequence set by the service index sequence setting unit as the imaginary part sequence of the complex training sequence. In the time domain, the discrete sample blocks that constitute the complex training sequence, the length of the training sequence, the service index sequence, and the discrete sample block of the complex training sequence are all X, and the service index sequence contains and uniquely expresses each resistance in the single frequency network. Each system parameter and service mode information of the noise mobile digital broadcasting signal transmitter, where X takes one of 512, 1024, and 2048;

8) Each anti-noise mobile digital broadcast signal transmitter in the single frequency network repeats the discrete sample value block of the complex training sequence formed on the time domain continuously for 4 times in the time domain to form a time domain embedded training sequence discrete sample value block, The length of the time-domain embedding training sequence discrete sample value block is equal to the length of the peak-to-average power ratio space-frequency modulation time-domain discretely encoded data sample block, that is, K=4×X; when X is 512, K is 2048, the frequency interval of the corresponding subcarrier is 4KHz; when X is 1024, K is 4096, and the frequency interval of the corresponding subcarrier is 2KHz; when X is 2048, K is 8192, and the corresponding subcarrier The frequency interval is 1KHz;

9) Each anti-noise mobile digital broadcast signal transmitter in the single frequency network directly superimposes the time-domain discrete coded data sample blocks and the time-domain embedded training sequence discrete sample blocks to form the time-domain embedded training Sequential reduced peak-to-average power ratio space-frequency modulation time-domain discretely coded data sample block, as a frame body;

10) Each anti-noise mobile digital broadcast signal transmitter in the single frequency network uses the cyclic prefix as a guard interval, that is, the frame header is inserted into the training sequence in the time domain, and the peak-to-average power ratio is reduced by space-frequency modulation. The time-domain discretely encoded data sample block is the frame body , to form a signal frame, the length of the cyclic prefix is C; when X is 512, C is 1/4 of the size of K; when X is 1024, C is 1/8 of the size of K; when X is 2048, C Take 1/16 of K size;

11) Each anti-noise mobile digital broadcast 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;

12) Each anti-noise mobile digital broadcast signal transmitter in the single frequency network up-converts the baseband signal to the carrier to form a radio frequency signal and transmit it to the wireless channel in the air;

13) The anti-noise mobile digital broadcast signal receiver in the single frequency network detects and receives the radio frequency signal sent by each anti-noise mobile digital broadcast signal transmitter in the single frequency network and converts it down to form a baseband signal, and utilizes the cycle of the signal frame Prefix characteristics and structural characteristics of the signal frame are used for baseband signal reception processing.

According to the embodiment of the signal frame formation (assuming that there are N transmitters in the single frequency network) in the signal transmission process between the transmitter and the receiver of the single frequency network anti-noise mobile digital broadcasting signal transmission method of the present invention, as shown in Figure 2 , the specific implementation is as follows:

The central data manager of the single frequency network converts the multimedia data stream into a bit stream through the media data processor, and uses the scrambling code sequence generated by the feedback shift register to perform scrambling processing to form the input data bit stream.

The network data manager of the single frequency network forms an FFT encoded data block in the frequency domain after the input data bit stream undergoes LDPC encoding, symbol modulation and symbol rotation; The formed FFT encoded data block is modulated to each anti-noise mobile digital broadcast signal transmitter branch in the single frequency network to form a space-frequency modulation FFT encoded data block, and the time synchronization of each anti-noise mobile digital broadcast signal transmitter branch is adjusted to Ensure that all transmitters in the network process the space-frequency modulation FFT coded data block at the same time; and then transform it into space-frequency modulation time-domain discrete coded data sample block through IFFT, and generate it through the peak-to-average power ratio adjustment unit Select the data sample block with reduced peak-to-average power ratio space-frequency modulation time-domain discrete coding with the lowest peak-to-average power ratio, and send the corresponding generated mode information to the service index sequence setting unit. The symbol modulation is one of QPSK, 16QAM, 64QAM and 256QAM. The symbol constellation mapping method of symbol modulation adopts Gray code mapping; the symbol rotation is realized by rotating the symbol constellation at a certain angle. The QPSK symbol The rotation angle of the constellation diagram is 22.5 degrees, the rotation angle of the symbol constellation diagram of 16QAM is 11.25 degrees, the rotation angle of the symbol constellation diagram of 64QAM is 5.626 degrees, and the rotation angle of the symbol constellation diagram of 256QAM is 2.8125 degrees. Space-frequency modulated FFT encoded data blocks are composed of subcarriers. The length of the space-frequency modulation FFT coded data block is K; when X is 512, the corresponding K is 2048, and the frequency interval of the corresponding subcarrier is 4KHz; when X is 1024, the corresponding K is 4096, and the corresponding The frequency interval of the corresponding subcarriers is 2KHz; when X is 2048, the corresponding K is 8192, and the frequency interval of the corresponding subcarriers is 1KHz. Each anti-noise mobile digital broadcast signal transmitter in the single frequency network uses the training sequence as the real part sequence of the complex training sequence and the service index sequence as the imaginary part sequence of the complex training sequence, and forms discrete samples of the complex training sequence in the time domain value block, and then repeat it four times continuously in the time domain to form a time domain embedded training sequence discrete sample value block. The length of the discrete sample block of the training sequence, the service index sequence, and the complex training sequence is X, where X is one of 512, 1024, and 2048, and the length of the discrete sample block of the time domain embedded training sequence is K, K=4× X. As the training sequence and service index sequence of each anti-noise mobile digital broadcast signal transmitter in the single frequency network, it is composed of a series of 1 or -1, which has pseudo-random characteristics, and the training sequence and service index sequence are orthogonal to each other. ; The training sequence satisfying the above characteristics can be realized by a special type of shifted m sequence as a pseudo-random number sequence and a Walsh sequence as an orthogonal sequence, a Hadamard sequence or an orthogonal sequence generated by other means; Each different service index sequence contains and uniquely expresses each system parameter and service mode information of each anti-noise mobile digital broadcasting signal transmitter in the single frequency network. Each anti-noise mobile digital broadcasting signal transmitter in the single frequency network directly superimposes the time-domain discrete coded data sample blocks and the time-domain embedded training sequence discrete sample blocks to form the time-domain embedded training sequence. The peak-to-average power ratio space-frequency modulation time-domain discretely encoded data sample block is used as a frame body; the peak-to-average power ratio space-frequency modulation time-domain discretely coded data sample block is inserted into the time-domain embedded training sequence as a guard interval, Form a signal frame. The length of the cyclic prefix used as the guard interval is C; when X takes 512, the corresponding C takes 1/4 of the size of K; when X takes 1024, the corresponding C takes 1/8 of the size of K; when X takes When 2048, the corresponding C takes 1/16 of the size of K. Each noise-resistant mobile digital broadcasting signal transmitter in the single frequency network uses a square root raised cosine roll-off filter to pulse-shape the signal of the signal frame. When X is 512, the roll-off coefficient of the square root raised cosine roll-off filter corresponding to the pulse shaping of the signal frame is 0.1; when X is 1024, the corresponding pulse shaping of the signal frame is The roll-off coefficient of the square root raised cosine roll-off filter is 0.05; when X is 2048, the corresponding roll-off coefficient of the square root raised cosine roll-off filter for pulse shaping the signal frame is 0.025.

Each anti-noise mobile digital broadcast signal transmitter in the single frequency network up-converts the baseband signal to the carrier to form a radio frequency signal and transmits it to the wireless channel in the air.

The anti-noise mobile digital broadcast signal receiver in the single frequency network detects and receives the radio frequency signal sent by each anti-noise mobile digital broadcast signal transmitter in the single frequency network and converts it down to form a baseband signal, using the cyclic prefix characteristic of the signal frame The baseband signal receiving process is carried out according to the structural characteristics of the signal frame, including the time-frequency domain joint iterative separation processing of the signal frame header and the signal frame body.

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 (8)

1. a single-frequency network anti-noise mobile digital broadcast method for transmitting signals is characterized in that it comprises the following steps:

1) the centre data manager of single frequency network converts the multi-medium data media data processor of flowing through to bit stream, and the scrambler sequence of utilizing feedback shift register to produce is carried out scrambling and handled to form the input data bit flow;

2) the network data management device of single frequency network will be imported flow through LDPC coding, code element modulation of data bit and form the FFT coded data block with code element rotation back on frequency domain, and LDPC represents low-density checksum, and the length of FFT coded data block is K; Code element is modulated to a kind of among QPSK, 16QAM, 64QAM and the 256QAM, and the symbol constellations figure mapping mode of code element modulation adopts the Gray code mapping; The code element rotation realizes by symbol constellations figure is rotated to an angle, the symbol constellations figure anglec of rotation of QPSK is 22.5 degree, the symbol constellations figure anglec of rotation of 16QAM is 11.25 degree, the symbol constellations figure anglec of rotation of 64QAM is 5.626 degree, and the symbol constellations figure anglec of rotation of 256QAM is 2.8125 degree;

3) to adopt code check be that FFT coded data block that 1 space-frequency coding device will form on frequency domain is modulated to form on each antinoise mobile digital broadcast signal transmitter branch road in the single frequency network and emptyly frequently modulates the FFT coded data block to the network data management device of single frequency network, and the time synchronized of adjusting each antinoise mobile digital broadcast signal transmitter branch road is all modulated the FFT coded data block frequently to sky at one time and handled to guarantee all transmitters in the network;

4) each antinoise mobile digital broadcast signal transmitter in the single frequency network adopts IFFT that sky is modulated the FFT coded data block frequently and is transformed to the empty time domain discrete coded data sample value piece D that frequently modulates _Total

5) each antinoise mobile digital broadcast signal transmitter in the single frequency network is modulated sky frequently time domain discrete coded data sample value piece in order and is divided equally into two, the empty sub-piece D of time domain discrete coded data sample value that frequently modulates ₁Frequently modulate the sub-piece D of time domain discrete coded data sample value with sky ₂, D _Total=[D ₁, D ₂];

6) each antinoise mobile digital broadcast signal transmitter in the single frequency network is modulated the sub-piece D of time domain discrete coded data sample value by the peak-to-average power ratio adjustment unit frequently to sky ₁, the empty sub-piece D of time domain discrete coded data sample value that frequently modulates ₂Carry out that signal adds, subtracts, conjugate operation is handled and the synthetic new again empty time domain discrete coded data sample value piece D that frequently modulates _New, the new empty time domain discrete coded data sample value piece D that frequently modulates _NewAdopt following generate pattern to obtain, generate pattern 1 is D _New=[D ₁, D ₂], generate pattern 2 is $D_{\mathrm{new}}=[D_1,\sqrt{1/2}(D_1+D_2)],$ Generate pattern 3 is $D_{\mathrm{new}}=[D_1,\sqrt{1/2}(D_1-D_2)],$ Generate pattern 4 is $D_{\mathrm{new}}=[\sqrt{1/2}(D_1+D_2),D_2],$ Generate pattern 5 is $D_{\mathrm{new}}=[\sqrt{1/2}(D_1-D_2),D_2]$ Generate pattern 6 is $D_{\mathrm{new}}=[\sqrt{1/2}(D_1+D_2),\sqrt{1/2}(D_1-D_2)],$ Generate pattern 7 is D _New=[D ^* ₁, D ₂], generate pattern 8 is $D_{\mathrm{new}}=[{D^{*}}_1,\sqrt{1/2}({D^{*}}_1+D_2)],$ Generate pattern 9 is $D_{\mathrm{new}}=[{D^{*}}_1,\sqrt{1/2}({D^{*}}_1-D_2)],$ Generate pattern 10 is $D_{\mathrm{new}}=[\sqrt{1/2}({D^{*}}_1+D_2),D_2],$ Generate pattern 11 is $D_{\mathrm{new}}=[\sqrt{1/2}({D^{*}}_1-D_2),D_2],$ Generate pattern 12 is $D_{\mathrm{new}}=[\sqrt{1/2}({D^{*}}_1+D_2),\sqrt{1/2}({D^{*}}_1-D_2)],$ Relatively 12 kinds of synthetic empty frequencies of generate pattern are modulated time domain discrete coded data sample value piece D _New, choose the empty frequency of peak-to-average power ratio that falls that wherein has minimum peak-to-average power ratio and modulate time domain discrete coded data sample value piece

And the empty time domain discrete coded data sample value piece of frequently modulating of peak-to-average power ratio will fall

The corresponding generate pattern information that adopts send to the operational indicator sequence unit be set, wherein, D ^* ₁Expression is modulated the sub-piece D of time domain discrete coded data sample value frequently to sky ₁Each empty modulate that time domain discrete coded data sample value carries out that conjugate operation is handled frequently and the empty sub-piece of time domain discrete coded data sample value of frequently modulating that obtains;

7) each antinoise mobile digital broadcast signal transmitter in the single frequency network is with the real part sequence of training sequence as sequence of plural training, the operational indicator sequence is provided with the imaginary part sequence of the set operational indicator sequence in unit as sequence of plural training, on time domain, constitute the discrete sample block of sequence of plural training, training sequence, the operational indicator sequence, the length of the discrete sample block of sequence of plural training all is X, and the operational indicator sequence is comprising and unique each system parameters and business model information of expressing each antinoise mobile digital broadcast signal transmitter in the single frequency network;

8) each antinoise mobile digital broadcast signal transmitter in the single frequency network will repeat 4 times continuously and form time domain embedding training sequence discrete sample block on time domain in the discrete sample block of the sequence of plural training that constitutes on the time domain, time domain embeds the length of training sequence discrete sample block and falls the empty length numerically equal of frequently modulating time domain discrete coded data sample value piece of peak-to-average power ratio, i.e. K=4 * X;

9) each antinoise mobile digital broadcast signal transmitter in the single frequency network will fall the empty time domain discrete coded data sample value piece, time domain frequently modulated of peak-to-average power ratio and embed training sequence discrete sample block and directly superpose and form time domain and embed training sequence and fall that peak-to-average power ratio is empty frequently modulates time domain discrete coded data sample value piece, as frame;

10) each antinoise mobile digital broadcast signal transmitter in the single frequency network at interval is that frame head inserts time domain and embeds training sequence and fall peak-to-average power ratio empty frequently to modulate time domain discrete coded data sample value piece be frame with Cyclic Prefix as protection, to form signal frame, the length of Cyclic Prefix is C;

11) each antinoise mobile digital broadcast signal transmitter in the single frequency network adopts square root raised cosine filter that the signal pulse of signal frame is shaped;

12) each antinoise mobile digital broadcast signal transmitter in the single frequency network forms emission of radio frequency signals to the on-air radio channel with the baseband signal up-conversion to carrier wave;

13) the antinoise mobile digital broadcast signal receiver in the single frequency network detect to receive radiofrequency signal that each antinoise mobile digital broadcast signal transmitter in the single frequency network sent and its down-conversion is formed baseband signal, utilizes the architectural characteristic of the Cyclic Prefix characteristic of signal frame and signal frame to carry out baseband signal and receives and handle.

2. by the single-frequency network anti-noise mobile digital broadcast method for transmitting signals of claim 1, it is characterized in that: the length X of the discrete sample block of the training sequence of each antinoise mobile digital broadcast signal transmitter in the described single frequency network, operational indicator sequence, sequence of plural training is got in 512,1024,2048.

3. by the single-frequency network anti-noise mobile digital broadcast method for transmitting signals of claim 2, it is characterized in that: described training sequence, operational indicator sequence are formed by a series of 1 or-1, have pseudo-random characteristics.

4. by the single-frequency network anti-noise mobile digital broadcast method for transmitting signals of claim 2, it is characterized in that: described training sequence, operational indicator sequence have orthogonality each other.

5. by the single-frequency network anti-noise mobile digital broadcast method for transmitting signals of claim 1, it is characterized in that: the described encoding rate that the input data are carried out the LDPC coding is in 1/4,1/2,5/8,3/4 and 7/8.

6. by the single-frequency network anti-noise mobile digital broadcast method for transmitting signals of claim 1, it is characterized in that: described empty frequency is modulated the FFT coded data block and is made up of subcarrier; When X got 512, sub-carrier number got 2048, and the frequency interval of subcarrier is got 4KHz; When X got 1024, sub-carrier number got 4096, and the frequency interval of subcarrier is got 2KHz; When X got 2048, sub-carrier number got 8192, and the frequency interval of subcarrier is got 1KHz.

7. by the single-frequency network anti-noise mobile digital broadcast method for transmitting signals of claim 1, it is characterized in that: the length C value of described Cyclic Prefix is relevant with the X value; When X got 512, C got 1/4 of K size; When X got 1024, C got 1/8 of K size; When X got 2048, C got 1/16 of K size.

8. press the single-frequency network anti-noise mobile digital broadcast method for transmitting signals of claim 1, it is characterized in that: the baseband signal that described single-frequency network anti-noise mobile digital broadcast signal receiver is carried out receives to be handled, and one of them step is that the time domain and frequency domain combined alternate analysis of signal frame head and signal frame body is handled.

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