CN102263736B - Anti-fading digital broadcast wireless signal transmitting method - Google Patents

Abstract

The invention discloses an anti-fading digital broadcast wireless signal transmitting method, and relates to a time domain/frequency domain mixed scheme. The anti-fading digital broadcast wireless signal transmitting method has the advantages of low peak-to-average power ratio, short synchronization time, resistance to fading, controllable multiple services and the like.

Description

A digital broadcast wireless signal anti-fading transmission method

technical field

The invention belongs to the field of wireless communication, and more specifically relates to a digital broadcast wireless signal anti-fading transmission method.

Background technique

Digital TV, digital broadcasting and wireless related technologies and related industries are industries with rapid development and good market prospects in the field of communication and computer. Digital broadcast wireless signal anti-fading transmitter transmission technology is the key technology of digital TV digital broadcast wireless 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 digital broadcasting wireless transmission system.

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.

Under multipath fading channels, the cascade optimization design of coding, interleaving and modulation schemes can achieve the largest possible signal diversity order, so as to obtain independent fading in symbol sequences equal to or exceeding the minimum free distance. Cascading different coding forms can make full use of the advantages of different coding techniques; inserting a bit interleaver between coding and symbol modulation can make the coding and modulation processes relatively independent and expand the diversity order from different multi-ary symbols To a different number of binary bits, so that the order of diversity is significantly improved and has good error characteristics in multipath fading channels.

In the actual communication environment, the performance of digital TV digital broadcasting wireless communication system is affected by factors such as synchronization time, clock jitter, channel fading, and channel interference. The digital broadcast wireless signal anti-fading transmitter transmission method is the key technology to realize the reliable digital TV digital broadcast wireless transmission.

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

Based on the above background, the present invention proposes a digital broadcast wireless signal anti-fading transmission method for the actual communication environment, which can meet the needs of high data rate controllable multi-service digital TV digital broadcast wireless 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.

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.

G.Caire, G.Taricco, E.Biglieri, "Bit-interleaved coded modulation," IEEE Trans.Information Theory, vol.44, no.3, pp.927-946, May 1998.

S. Benedetto, D. Divsalar, G. Montorsi, and F. Pollara, "Serial concatenation of interleaved codes: performance analysis, design, and iterative decoding," IEEE Trans. Inform. Theory, vol.44, no.3, pp.909 -925, May 1998.

Contents of the invention

Aiming at the problem of high data rate controllable multi-service digital TV digital broadcast wireless transmission, the invention proposes a digital broadcast wireless signal anti-fading transmission method.

A kind of digital broadcast wireless signal anti-fading transmission method that the present invention proposes is characterized in that it comprises the following steps:

1) The digital broadcast wireless signal anti-fading transmitter 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;

2) The digital broadcast wireless signal anti-fading transmitter passes its input data bits through RS coding (Reed-Solomon, RS), convolutional interleaving, LDPC coding (Low Density Parity Check, LDPC), symbol modulation, and symbol interleaving Form the FFT cascaded interleaved coding modulation data block in the frequency domain afterward, FFT represents fast discrete Fourier transform, and the length of the FFT cascade interleaving coding modulation data block is K;

3) The digital broadcast wireless signal anti-fading transmitter adopts IFFT to transform the FFT concatenated interleaved coded modulation data block into a time-domain discrete concatenated interleaved coded modulated data sample block D _total , and IFFT means inverse fast discrete Fourier transform;

4) The digital broadcast wireless signal anti-fading transmitter divides the time-domain discrete cascaded interleaved coded modulation data sample block into two blocks in sequence, the time-domain discrete cascaded interleaved coded modulated data sample sub-block D ₁ and the time-domain discrete level Interleaved coded modulation data sample sub-block D ₂ , D _total = [D ₁ , D ₂ ];

并将降峰均功率比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^* ₁表示对时域离散级联交织编码调制数据样值子块D₁的各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时域离散级联交织编码调制数据样值子块；5) The anti-fading transmitter of the digital broadcast wireless signal uses the peak-to-average power ratio adjustment unit to perform the time-domain discrete concatenated interleaving coded modulation data sample sub-block D ₁ and the time-domain discrete concatenated interleaved coded modulated data sample sub-block D ₂ Signal addition, subtraction, and conjugate operation processing and re-synthesis of a new time-domain discrete concatenated interleaved coded modulation data sample block _Dnew , the new time-domain discrete concatenated interleaved coded modulated data sample block _Dnew is obtained by the following generation mode , generation mode 1 is D _new = [D ₁ , D ₂ ], 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 time-domain discrete concatenated interleaved coded modulation data sample block _Dnew synthesized by 12 generation modes, and select the time-domain discrete concatenated interleaved coded modulated data sample block with the lowest peak-to-average power ratio among them

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

The corresponding generation mode information adopted is sent to the service index sequence setting unit, wherein, D ^* ₁ represents each time-domain discrete concatenated interleaving coded modulation data sample value for the time domain discrete concatenated interleaved coded modulation data sample sub-block D ₁ Time-domain discrete concatenated interleaved coded modulation data sample sub-block obtained by performing conjugate operation processing;

6) The digital broadcast wireless signal anti-fading transmitter inserts the cyclic prefix as a guard interval into the peak-to-average power ratio time-domain discrete concatenated interleaved coding modulation data sample block to form a peak-to-average power ratio time-domain cyclic prefix discrete cascaded interleaved code The modulated data sample block is used as a frame body, the length of the cyclic prefix is C, and the length of the peak-to-average power ratio time-domain cyclic prefix discrete concatenated interleaved coded modulated data sample block is C+K;

7) The digital broadcast wireless signal anti-fading transmitter 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 to form a complex training sequence in the time domain The discrete sample value block of the sequence, the length of the discrete sample value block of the training sequence, the service index sequence, and the complex number training sequence are all X, and the service index sequence contains and uniquely expresses the system parameters of the digital broadcasting wireless signal anti-fading transmitter and business model information;

8) The digital broadcast wireless signal anti-fading transmitter repeats the discrete sample blocks of the complex training sequence formed in the time domain continuously twice in the time domain to form the discrete sample blocks of the repeated training sequence in the time domain as the frame header;

9) The digital broadcast wireless signal anti-fading transmitter inserts the time-domain repetitive training sequence discrete sample block, that is, the frame header, into the peak-to-average power ratio time-domain cyclic prefix discrete cascaded interleaving coded modulation data sample block, that is, the frame body, to form signal frame;

10) The digital broadcast wireless signal anti-fading transmitter adopts the square root raised cosine roll-off filter to shape the signal pulse of the signal frame;

11) Digital broadcast wireless signal anti-fading transmitter converts the baseband signal up-converted to the carrier to form a radio frequency signal and transmit it to the wireless channel in the air;

12) The digital broadcast wireless signal anti-fading receiver detects and receives the radio frequency signal sent by the digital broadcast wireless signal anti-fading transmitter and converts it down to form a baseband signal, and uses the cyclic prefix characteristics of the signal frame and the structural characteristics of the signal frame to perform baseband signal Receive processing.

According to the above-mentioned digital broadcast wireless signal anti-fading transmission method, it is characterized in that: the peak-to-average power ratio of the digital broadcast wireless signal anti-fading transmitter is reduced by the time-domain discrete concatenated interleaving coded modulation data sample block is encoded by the time-domain discrete concatenated interleaved code Modulated data sample sub-blocks are re-synthesized through signal addition, subtraction, and conjugate operation processing for 12 specific generation modes; digital broadcast wireless signal anti-fading transmitter signal frames have periodic time-domain repetitive training sequences discrete Sample block; the length X of the training sequence of the digital broadcast wireless signal anti-fading transmitter is one of 512, 1024, 2048, and the length K of the corresponding FFT concatenated interleaved coded modulation data block is 2048, 4096, 8192 respectively, The frequency intervals of the corresponding subcarriers are 4KHz, 2KHz, and 1KHz respectively, and the corresponding cyclic prefix lengths C are 1/4, 1/8, and 1/16 of the length K of the FFT concatenated interleaving coded modulation data block; the numbers The training sequence and service index sequence of broadcast wireless signal anti-fading transmitter are composed of a series of 1 or -1, which have pseudo-random characteristics; the training sequence and service index sequence of digital broadcast wireless signal anti-fading transmitter are orthogonal to each other The different service index sequences of the digital broadcast wireless signal anti-fading transmitter contain and uniquely express the system parameters and business mode information of the digital broadcast wireless signal anti-fading transmitter; the coding rate of LDPC coding is 1/4, One of 1/2, 5/8, 3/4, and 7/8; random interleaving is used for bit interleaving; one of QPSK, 16QAM, 32QAM, and 64QAM is used for symbol modulation, and Gray is used for symbol constellation mapping Code mapping; symbol interleaving adopts random interleaving. The digital broadcast wireless signal anti-fading receiver can make full use of the cyclic prefix characteristics of the signal frame and the structural characteristics of the signal frame for baseband signal reception processing, including joint iterative separation processing of the signal frame header and signal frame body in the time-frequency domain.

Features of the present invention:

The present invention is a mixed transmission scheme of time domain and frequency domain. The generation mode of the peak-to-average power ratio time-domain discrete concatenated interleaved coded modulation data sample block and the method for selecting the peak-to-average power ratio time-domain discrete cascaded interleaved coded modulated data sample block with the lowest peak-to-average power ratio of the present invention , not only can make full use of the maximum peak power of OFDM signal is very high but the probability of high peak power signal is very low, when the number of subcarriers is large, the real part (or imaginary part) of OFDM signal is a complex Gaussian random process and the amplitude obeys Rayleigh distribution The characteristics of the used generation mode require a small amount of additional information to be sent, and it is easy to process and restore the original signal of the OFDM signal at the receiver without destroying the orthogonality of the subcarrier signal and generating additional nonlinearity distortion. The signal frame of the digital broadcast wireless signal anti-fading transmitter has periodic time-domain repeated training sequence discrete sample blocks, the digital broadcast wireless signal anti-fading transmitter training sequence, and the service index sequence have pseudo-random characteristics, and the digital broadcast wireless signal The training sequence and service index sequence of the anti-fading transmitter are orthogonal to each other. The signal frame of the digital broadcast wireless signal anti-fading transmitter is inserted into the peak-to-average power ratio by inserting the discrete sample block of the time-domain repeated training sequence, that is, the frame header. Time-domain cyclic prefix discrete concatenated interleaved coding modulated data sample block is formed, which ensures that the digital broadcast wireless signal anti-fading receiver can achieve fast and accurate frame synchronization, frequency synchronization, time synchronization, channel transmission characteristic estimation, As well as reliable tracking of phase noise and channel transfer characteristics. The cyclic prefix is inserted as a guard interval into the peak-to-average power ratio time-domain discrete concatenated interleaved coded modulation data sample block to form a signal frame body, which can reduce the interference effect between the signal frame header and the frame body concatenated interleaved coded modulated data. 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. The various service index sequences of the digital broadcast wireless signal anti-fading transmitter contain and uniquely express the system parameters and business mode information of the digital broadcast wireless signal anti-fading transmitter, which can enable the digital TV digital broadcast wireless transmission system to provide free TV broadcasting, paid TV broadcasting, confidential information transmission, multimedia value-added services, etc. can control multiple services to meet social needs. The transmission method of the present invention has many advantages such as low peak-to-average power ratio, short synchronization time, small clock jitter, anti-channel fading, anti-channel interference, and can provide high-level interleaving code modulation data rate controllable multi-service digital TV digital broadcasting wireless transmission, etc. .

Description of drawings

FIG. 1 is a schematic diagram of an embodiment of signal transmission between a certain transmitter and a receiver according to a digital broadcast wireless signal anti-fading transmission method of the present invention.

Fig. 2 is a schematic diagram of an embodiment of signal frame formation during signal transmission between a transmitter and a receiver in a digital broadcast wireless signal anti-fading transmission method according to the present invention.

Detailed ways

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

A schematic diagram of an embodiment of signal transmission between a certain transmitter and a receiver according to the digital broadcasting wireless signal anti-fading transmission method proposed by the present invention, as shown in Figure 1, proceed in the following steps:

1) The digital broadcast wireless signal anti-fading transmitter converts the multimedia data stream into a bit stream through a 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 certain digital broadcast wireless signal anti-fading transmitter passes its input data bit stream through RS coding (Reed-Solomon, RS), convolutional interleaving, LDPC coding (Low Density Parity Check, LDPC), symbol modulation, After symbol interleaving, an FFT concatenated interleaving coded modulation data block is formed in the frequency domain, FFT means fast discrete Fourier transform, and the length of the FFT concatenated interleaved coded modulated data block is K; the coding rate of LDPC code is 1/4, 1/ One of 2, 5/8, 3/4, and 7/8; the symbol modulation is one of QPSK, 16QAM, 32QAM, and 64QAM, and the symbol constellation mapping method adopts Gray code mapping; the symbol interleaving adopts random interleaving Way;

3) The certain digital broadcast wireless signal anti-fading transmitter adopts IFFT to transform the FFT concatenated interleaved coded modulation data block into a time-domain discrete concatenated interleaved coded modulated data sample block D _total , and IFFT stands for Inverse Fast Discrete Fourier Transform;

4) The certain digital broadcast wireless signal anti-fading transmitter divides the time-domain discrete concatenated interleaved coded modulation data sample block into two blocks in sequence, and the time domain discrete concatenated interleaved coded modulated data sample sub-block _D1 and time domain Domain discrete concatenated interleaving coding modulated data sample sub-block D ₂ , D _total = [D ₁ , D ₂ ];

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表示对时域离散级联交织编码调制数据样值子块D₁的各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时域离散级联交织编码调制数据样值子块；5) The certain digital broadcast wireless signal anti-fading transmitter uses the peak-to-average power ratio adjustment unit to adjust the time-domain discrete concatenated interleaved coded modulation data sample sub-block D ₁ , the time-domain discrete concatenated interleaved coded modulated data sample sub-block D ₂ performs signal addition, subtraction, and conjugate operation processing and re-synthesizes a new time-domain discrete concatenated interleaved coded modulation data sample block _Dnew , and the new time-domain discrete concatenated interleaved coded modulated data sample block _Dnew is as follows The generation 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 time-domain discrete concatenated interleaved coded modulation data sample block _Dnew synthesized by 12 generation modes, and select the time-domain discrete concatenated interleaved coded modulated data sample block with the lowest peak-to-average power ratio among them And reduce the peak-to-average power ratio time-domain discrete concatenated interleaved coding modulation data sample block

The corresponding generation mode information adopted is sent to the service index sequence setting unit, wherein, D ^* ₁ represents each time-domain discrete concatenated interleaving coded modulation data sample value for the time domain discrete concatenated interleaved coded modulation data sample sub-block D ₁ Time-domain discrete concatenated interleaved coded modulation data sample sub-block obtained by performing conjugate operation processing;

6) The digital broadcast wireless signal anti-fading transmitter inserts the cyclic prefix as a guard interval into the peak-to-average power ratio time-domain discrete concatenated interleaved coding modulation data sample block to form a peak-to-average power ratio time-domain cyclic prefix discrete cascaded interleaved code The modulated data sample block is used as a frame body, the length of the cyclic prefix is C, and the length of the peak-to-average power ratio time-domain cyclic prefix discrete concatenated interleaved coded modulated data sample block is C+K;

7) The digital broadcast wireless signal anti-fading transmitter 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 to form a complex training sequence in the time domain The discrete sample value block of the sequence, the length of the discrete sample value block of the training sequence, the service index sequence, and the complex number training sequence are all X, and the service index sequence contains and uniquely expresses the system parameters of the digital broadcasting wireless signal anti-fading transmitter and For business mode information, X is one of 512, 1024, and 2048; when X is 512, K is 2048, C is 1/4 of the size of K, and the frequency interval of FFT concatenated interleaving code modulation data block subcarriers is 4KHz; When X is 1024, K is 4096, C is 1/8 of the size of K, and the frequency interval of the FFT concatenated interleaving code modulation data block subcarrier is 2KHz; when X is 2048, K is 8192, and C is of the size of K 1/16, the frequency interval of FFT cascaded interleaving coding modulation data block subcarriers is 1KHz;

8) The digital broadcast wireless signal anti-fading transmitter repeats the discrete sample blocks of the complex training sequence formed in the time domain continuously twice in the time domain to form the discrete sample blocks of the repeated training sequence in the time domain as the frame header;

9) The digital broadcast wireless signal anti-fading transmitter inserts the time-domain repetitive training sequence discrete sample block, that is, the frame header, into the peak-to-average power ratio time-domain cyclic prefix discrete cascaded interleaving coded modulation data sample block, that is, the frame body, to form signal frame;

10) The certain digital broadcast wireless signal anti-fading transmitter adopts a square root raised cosine roll-off filter to shape the signal pulse of the signal frame;

11) The digital broadcast wireless signal anti-fading transmitter up-converts the baseband signal to the carrier to form a radio frequency signal and transmits it to the air wireless channel;

12) The digital broadcast wireless signal anti-fading receiver detects and receives the radio frequency signal sent by the digital broadcast wireless signal anti-fading transmitter and converts it down to form a baseband signal, using the cyclic prefix characteristics of the signal frame and the structural characteristics of the signal frame Perform baseband signal reception processing, including joint iterative separation processing of the time-frequency domain of the signal frame header and signal frame body.

According to the schematic diagram of an embodiment of signal frame formation in the signal transmission process between a certain transmitter and a receiver of the digital broadcast wireless signal anti-fading transmission method of the present invention, as shown in Figure 2, the specific implementation is as follows:

The digital radio signal anti-fading transmitter converts the multimedia data stream into a bit stream through a 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.

The anti-fading transmitter of a certain digital broadcast wireless signal forms an FFT concatenated interleaved coded modulation data block in the frequency domain after its input data bit stream undergoes RS coding, convolutional interleaving, LDPC coding, symbol modulation, and symbol interleaving , the length of the FFT concatenated interleaved coded modulation data block is K, and the FFT concatenated interleaved coded modulated data block is composed of subcarriers, and then transformed into discrete concatenated interleaved coded modulated data sample blocks in the time domain by IFFT, through the peak-average The power ratio adjustment unit generates and selects the reduced peak-to-average power ratio time-domain discrete concatenated interleaving coded modulation data sample block with the lowest peak-to-average power ratio, and sends the corresponding generation mode information to the service index sequence setting unit. The coding rate of LDPC coding is one of 1/4, 1/2, 5/8, 3/4 and 7/8; the symbol modulation is one of QPSK, 16QAM, 32QAM and 64QAM, and the symbol constellation map mapping The method adopts Gray code mapping; the symbol interleaving adopts the random interleaving method.

The digital radio signal anti-fading transmitter inserts the cyclic prefix as a guard interval into the peak-to-average power ratio time-domain discrete concatenated interleaving coded modulation data sample block to form a peak-to-average power ratio time-domain cyclic prefix discrete cascade interleaving Coded and modulated data sample blocks are used as a frame body, and the length of the cyclic prefix is C.

The digital broadcast wireless signal anti-fading transmitter 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 to form a complex number in the time domain The discrete sample value block of the training sequence, the length of the discrete sample value block of the training sequence, the service index sequence and the complex training sequence are all X, and the service index sequence contains and uniquely expresses the system parameters of the digital broadcast wireless signal anti-fading transmitter and business model information.

The certain digital broadcast wireless signal anti-fading transmitter continuously repeats the discrete sample blocks of the complex training sequence formed in the time domain twice in the time domain to form the discrete sample blocks of the time domain repetitive training sequence as the frame header.

The certain digital broadcast wireless signal anti-fading transmitter inserts the time-domain repetitive training sequence discrete sample block, that is, the frame header, into the peak-to-average power ratio time-domain cyclic prefix discrete concatenated interleaved coded modulation data sample block, that is, the frame body, to Form a signal frame.

The certain digital broadcast wireless signal anti-fading transmitter adopts the square root raised cosine roll-off filter to shape the signal pulse of the signal frame.

One of 512, 1024, and 2048 is used for X of the certain digital broadcast wireless signal anti-fading transmitter; when X is 512, K is 2048, C is 1/4 of the size of K, and FFT concatenated interleaving coding modulates data blocks The frequency interval of subcarriers is 4KHz; when X is 1024, K is 4096, C is 1/8 of the size of K, and the frequency interval of subcarriers of FFT concatenated interleaving code modulation data block is 2KHz; when X is 2048, K Take 8192, C takes 1/16 of the size of K, and the frequency interval of FFT concatenated interleaving coding modulation data block subcarriers takes 1KHz; as the training sequence and service index sequence of the digital broadcast wireless signal anti-fading transmitter, 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 Walsh sequence, Hadamard sequence or orthogonal sequence generated by other methods as an orthogonal sequence. Each different service index sequence contains and uniquely expresses various system parameters and service mode information of the anti-fading transmitter of the digital broadcast wireless signal. 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.

The certain digital broadcast wireless signal anti-fading transmitter 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 digital broadcast wireless signal anti-fading receiver detects and receives the radio frequency signal sent by the digital broadcast wireless signal anti-fading transmitter and converts it down to form a baseband signal. Signal receiving processing, which includes time-frequency domain joint iterative separation processing of signal frame header and 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 digital broadcast wireless signal anti-fading transmission method is characterized in that it comprises the following steps: 1) The digital broadcast wireless signal anti-fading transmitter 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; 2) The digital broadcast wireless signal anti-fading transmitter forms the FFT concatenated interleaving code modulation data block in the frequency domain after its input data bit stream undergoes RS coding, convolutional interleaving, LDPC coding, symbol modulation, and symbol interleaving. RS means Reed-Solomon, LDPC means Low Density Parity Check, and the length of FFT concatenated interleaving coded modulation data block is K; 3) The digital broadcast wireless signal anti-fading transmitter adopts IFFT to transform the FFT concatenated interleaved coded modulation data block into a time-domain discrete concatenated interleaved coded modulated data sample block D _total ; 4) The digital broadcast wireless signal anti-fading transmitter divides the time-domain discrete cascaded interleaved coded modulation data sample block into two blocks in sequence, the time-domain discrete cascaded interleaved coded modulated data sample sub-block D ₁ and the time-domain discrete level Interleaved coded modulation data sample sub-block D ₂ , D _total = [D ₁ , D ₂ ]; 5) The anti-fading transmitter of the digital broadcast wireless signal uses the peak-to-average power ratio adjustment unit to perform the time-domain discrete concatenated interleaving coded modulation data sample sub-block D ₁ and the time-domain discrete concatenated interleaved coded modulated data sample sub-block D ₂ Signal addition, subtraction, and conjugate operation processing and re-synthesis of a new time-domain discrete concatenated interleaved coded modulation data sample block _Dnew , the new time-domain discrete concatenated interleaved coded modulated data sample block _Dnew is obtained by the following generation mode , generation mode 1 is D _new = [D ₁ , D ₂ ], 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 time-domain discrete concatenated interleaved coded modulation data sample block _Dnew synthesized by 12 generation modes, and select the time-domain discrete concatenated interleaved coded modulated data sample block with the lowest peak-to-average power ratio among them

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

The corresponding generation mode information adopted is sent to the service index sequence setting unit, wherein, D ^* ₁ represents each time-domain discrete concatenated interleaving coded modulation data sample value for the time domain discrete concatenated interleaved coded modulation data sample sub-block D ₁ Time-domain discrete concatenated interleaved coded modulation data sample sub-block obtained by performing conjugate operation processing; 6) The digital broadcast wireless signal anti-fading transmitter inserts the cyclic prefix as a guard interval into the peak-to-average power ratio time-domain discrete concatenated interleaved coding modulation data sample block to form a peak-to-average power ratio time-domain cyclic prefix discrete cascaded interleaved code The modulated data sample block is used as a frame body, the length of the cyclic prefix is C, and the length of the peak-to-average power ratio time-domain cyclic prefix discrete concatenated interleaved coded modulated data sample block is C+K; 7) The digital broadcast wireless signal anti-fading transmitter 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 to form a complex training sequence in the time domain The discrete sample value block of the sequence, the length of the discrete sample value block of the training sequence, the service index sequence, and the complex number training sequence are all X, and the service index sequence contains and uniquely expresses the system parameters of the digital broadcasting wireless signal anti-fading transmitter and business model information; 8) The digital broadcast wireless signal anti-fading transmitter repeats the discrete sample blocks of the complex training sequence formed in the time domain continuously twice in the time domain to form the discrete sample blocks of the repeated training sequence in the time domain as the frame header; 9) The digital broadcast wireless signal anti-fading transmitter inserts the time-domain repetitive training sequence discrete sample block, that is, the frame header, into the peak-to-average power ratio time-domain cyclic prefix discrete cascaded interleaving coded modulation data sample block, that is, the frame body, to form signal frame; 10) The digital broadcast wireless signal anti-fading transmitter adopts the square root raised cosine roll-off filter to shape the signal pulse of the signal frame; 11) Digital broadcast wireless signal anti-fading transmitter converts the baseband signal up-converted to the carrier to form a radio frequency signal and transmit it to the wireless channel in the air; 12) The digital broadcast wireless signal anti-fading receiver detects and receives the radio frequency signal sent by the digital broadcast wireless signal anti-fading transmitter and converts it down to form a baseband signal, and uses the cyclic prefix characteristics of the signal frame and the structural characteristics of the signal frame to perform baseband signal Receive processing. 2. by the digital broadcast wireless signal anti-fading transmission method of claim 1, it is characterized in that: the length X of the discrete sample value block of the training sequence of described digital broadcast wireless signal anti-fading transmitter, service index sequence, complex number training sequence is taken One of 512, 1024, 2048. 3. The digital broadcast wireless signal anti-fading transmission method according to claim 2, characterized in that: the training sequence and the service index sequence are composed of a series of 1 or -1, and have pseudo-random characteristics. 4. The digital broadcast wireless signal anti-fading transmission method according to claim 2, characterized in that: the training sequence and the service index sequence are orthogonal to each other. 5. by the digital broadcast wireless signal anti-fading transmission method of claim 1, it is characterized in that: the coding rate of described LDPC coding is one of 1/4, 1/2, 5/8, 3/4 and 7/8 ; The symbol modulation is one of QPSK, 16QAM, 32QAM and 64QAM, and the symbol constellation mapping method adopts Gray code mapping; the symbol interleaving adopts the random interleaving method. 6. by the digital broadcast wireless signal anti-fading transmission method of claim 1, it is characterized in that: said FFT cascading interleaved coding modulation data block is made up of sub-carrier; When X gets 512, K gets 2048, and the frequency interval of sub-carrier gets 4KHz; when X is 1024, K is 4096, and the subcarrier frequency interval is 2KHz; when X is 2048, K is 8192, and the subcarrier frequency interval is 1KHz. 7. by the digital broadcast wireless signal anti-fading transmission method of claim 1, it is characterized in that: the length C value of described cyclic prefix is relevant to X value; When X is 512, C is 1/4 of K size; When X takes 1024, C takes 1/8 of the size of K; when X takes 2048, C takes 1/16 of the size of K. 8. The digital broadcast wireless signal anti-fading transmission method according to claim 1, characterized in that: the baseband signal receiving process carried out by the digital broadcast wireless signal anti-fading receiver, one of the steps is a signal frame header and a signal frame body The time-frequency domain joint iterative separation process.

Images