CN102263752B - Method for transmitting anti-fading mobile digital broadcast signal - Google Patents

Abstract

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

Description

An anti-fading mobile digital broadcasting signal transmission method

technical field

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

Background technique

At present, television broadcasting has gradually developed from analog to digital. Digital TV broadcasting transmission system, as an important part of digital TV broadcasting, the development of its related technologies is closely related to people's quality of life, and therefore has received extensive attention from people. The technology related to digital TV broadcasting and related industries are industries with rapid development and good market prospects in the field of communication and computer. In terms of technologies related to digital TV broadcasting, countries are currently focusing on how to provide low-cost, reliable and high-speed mobile solutions for digital TV broadcasting in a complex wave propagation environment. Transmission technology is the key technology of digital TV broadcasting system, 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 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 broadcasting.

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

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

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

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

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.

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 anti-fading mobile digital broadcasting of high data rate controllable multi-service digital television, the invention proposes a transmission method of anti-fading mobile digital broadcasting.

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

1) The anti-fading mobile digital broadcast signal 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 anti-fading mobile digital broadcast signal transmitter passes its input data bit stream through RS coding (Reed-Solomon, RS), convolutional interleaving, LDPC coding (Low Density Parity Check, LDPC), symbol modulation and symbol rotation , After symbol interleaving, form FFT concatenated interleaved coded modulation data blocks in the frequency domain, FFT represents fast discrete Fourier transform, and the length of FFT concatenated interleaved coded modulated data blocks is K;

3) The anti-fading mobile digital broadcast signal transmitter uses 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 anti-fading mobile digital broadcast signal transmitter divides the time-domain discrete concatenated interleaved coded modulation data sample block into two blocks in sequence, the time-domain discrete concatenated 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 mobile digital broadcast signal transmitter 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 anti-fading mobile digital broadcast signal 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 blocks of the sequence, the length of the discrete sample value blocks 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 anti-fading mobile digital broadcasting signal transmitter and business model information;

7) The anti-fading mobile digital broadcasting signal transmitter repeats the discrete sample blocks of the complex training sequence formed in the time domain for 4 consecutive times in the time domain to form a time domain embedded training sequence discrete sample block, and the time domain embedded training sequence is discrete The length of the sample value block and the length of the peak-to-average power ratio time-domain discrete concatenated interleaved coded modulation data sample block are equal in value, that is, K=4×X;

8) The anti-fading mobile digital broadcast signal transmitter directly superimposes the peak-to-average power ratio of the time-domain discrete cascaded interleaved coded modulation data sample block and the time-domain embedded training sequence discrete sample block to form a time-domain embedded training sequence to reduce the peak-to-average power Than the time-domain discrete cascaded interleaved coding modulated data sample block, as a frame body;

9) The anti-fading mobile digital broadcast signal transmitter uses the cyclic prefix as a guard interval, that is, inserts the frame header into the time domain, embeds the training sequence, reduces the peak-to-average power ratio, and time-domain discrete cascade interleaving codes the modulated data sample block, that is, the frame body, to form a signal frame , the length of the cyclic prefix is C;

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

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

12) The anti-fading mobile digital broadcast signal receiver detects and receives the radio frequency signal sent by the anti-fading mobile digital broadcast signal 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 anti-fading mobile digital broadcasting signal transmission method, it is characterized in that: the peak-to-average power ratio of the anti-fading mobile digital broadcasting signal transmitter is reduced by the time-domain discrete concatenated interleaving coded modulation data sample block 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; the signal frame of the anti-fading mobile digital broadcasting signal transmitter has a periodic time-domain embedded training sequence discrete Sample value block; the length X of the training sequence of the anti-fading mobile digital broadcasting signal transmitter is one of 512, 1024, 2048, and the length K of the corresponding FFT concatenated interleaving 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 respectively 1/4, 1/8, and 1/16 of the length K of the FFT concatenated interleaving coded modulation data block; The training sequence and service index sequence of the fading mobile digital broadcast signal transmitter are composed of a series of 1 or -1, which have pseudo-random characteristics; the training sequence and service index sequence of the anti-fading mobile digital broadcast signal transmitter are orthogonal to each other The different service index sequences of the anti-fading mobile digital broadcasting signal transmitter contain and uniquely express the system parameters and service mode information of the anti-fading mobile digital broadcasting signal transmitter; the coding rate of LDPC coding is 1/4, One of 1/2, 5/8, 3/4, and 7/8; the symbol modulation is one of QPSK, 16QAM, 64QAM, and 256QAM, and the symbol constellation map uses Gray code mapping; the symbol rotation is passed The rotation angle of the symbol constellation diagram is realized by rotating a certain angle. 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. The rotation angle of the element constellation diagram is 2.8125 degrees; the code element interleaving adopts the random interleaving method. The anti-fading mobile digital broadcast signal 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 time-frequency domain of the signal frame header and signal frame body.

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 anti-fading mobile digital broadcast signal transmitter has periodic time-domain embedded training sequence discrete sample blocks, the training sequence and service index sequence of the anti-fading mobile digital broadcast signal transmitter have pseudo-random characteristics, and the anti-fading mobile digital The training sequence and service index sequence of the broadcast signal transmitter are orthogonal to each other, and the time-domain embedding training sequence of the anti-fading mobile digital broadcast signal transmitter reduces the peak-to-average power ratio to the time-domain discrete cascade interleaving coded modulation data sample block It is formed by the direct superposition of the time-domain discrete concatenated interleaved coded modulation data sample blocks and the time-domain embedded training sequence discrete sample blocks, which ensure that the anti-fading mobile digital broadcasting signal receiver can achieve fast and accurate frame synchronization, frequency synchronization, time synchronization, estimation of channel transmission characteristics, and reliable tracking of phase noise and channel transmission characteristics. Inserting the cyclic prefix as a guard interval into the time-domain embedding training sequence to reduce the peak-to-average power ratio time-domain discrete concatenated interleaving coding modulated data sample blocks to form a signal frame, which can reduce the interference between adjacent signal frames. 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. Symbol modulation and symbol rotation provide diversity effects for mobile digital broadcasting signals. Each different service index sequence of the anti-fading mobile digital broadcast signal transmitter contains and uniquely expresses the system parameters and business mode information of the anti-fading mobile digital broadcast signal transmitter, which can make the digital TV anti-fading mobile digital broadcast transmission system able to Provide controllable multi-services such as free TV broadcasting, paid TV broadcasting, 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, and can provide high-level interleaving code modulation data rate controllable multi-service digital TV anti-fading mobile digital broadcast transmission, etc. Many advantages.

Description of drawings

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

Fig. 2 is a schematic diagram of an embodiment of signal frame formation during signal transmission between a certain transmitter and a receiver according to the anti-fading 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 schematic diagram of an embodiment of signal transmission between a transmitter and a receiver of the anti-fading mobile digital broadcast signal transmission method proposed by the present invention, as shown in Figure 1, the following steps are carried out:

1) The certain anti-fading mobile digital broadcast signal 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 anti-fading mobile digital broadcast signal transmitter forms an FFT level in the frequency domain after its input data bit stream undergoes RS coding, convolutional interleaving, LDPC coding, symbol modulation, symbol rotation, and symbol interleaving Concatenated interleaved coded modulation data block, FFT means fast discrete Fourier transform, the length of FFT concatenated interleaved coded modulated data block is K; LDPC coded code rates are 1/4, 1/2, 5/8, 3/4 and 7 One of /8; the symbol modulation is one of QPSK, 16QAM, 64QAM and 256QAM, and the symbol constellation mapping method adopts Gray code mapping; the symbol rotation is realized by rotating the symbol constellation at a certain angle, and the QPSK The rotation angle of the symbol 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; the code element interleaving adopts Random interleaving.

3) The certain anti-fading mobile digital broadcast signal transmitter uses 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 anti-fading mobile digital broadcast signal transmitter divides the time-domain discrete concatenated interleaving 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 the time domain Domain discrete concatenated interleaving coding modulated 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 certain anti-fading mobile digital broadcasting signal transmitter adjusts the time-domain discrete concatenated interleaving coded modulation data sample sub-block D ₁ , the time domain discrete concatenated interleaved coded modulated data sample sub-block through the peak-to-average power ratio adjustment unit 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 certain anti-fading mobile digital broadcast signal 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, in the time domain The discrete sample value blocks that constitute the complex training sequence, the length of the training sequence, the service index sequence, and the discrete sample value block of the complex training sequence are all X, and the service index sequence contains and uniquely expresses each of the anti-fading mobile digital broadcasting signal transmitters. System parameters and business mode information, X takes one of 512, 1024, and 2048;

7) The certain anti-fading mobile digital broadcasting signal transmitter repeats the discrete sample blocks of the complex training sequence formed in the time domain continuously for 4 times in the time domain to form a time domain embedded training sequence discrete sample block, and the time domain embedding The length of the training sequence discrete sample block is equal to the length of the peak-to-average power ratio time-domain discrete concatenated interleaved coded modulation 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 frequency interval of the corresponding subcarrier Take 1KHz;

8) The certain anti-fading mobile digital broadcasting signal transmitter directly superimposes the peak-to-average power ratio time-domain discrete concatenated interleaving coded modulation data sample block and the time-domain embedded training sequence discrete sample block to form a time-domain embedded training sequence drop Peak-to-average power ratio time-domain discrete cascaded interleaved coded modulation data sample block, as a frame body;

9) The certain anti-fading mobile digital broadcast signal transmitter uses the cyclic prefix as a guard interval, that is, inserts the frame header into the time domain embedding training sequence, and reduces the peak-to-average power ratio time domain discrete cascade interleaving coding modulation data sample block, namely 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 is K 1/16 of the size;

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

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

12) The certain anti-fading mobile digital broadcasting signal receiver detects and receives the radio frequency signal sent by the anti-fading mobile digital broadcasting signal transmitter and down-converts it 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 process of signal transmission between a certain transmitter and receiver according to the anti-fading mobile digital broadcast signal transmission method of the present invention, as shown in Figure 2, the specific implementation is as follows:

The certain anti-fading mobile digital broadcast signal 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 certain anti-fading mobile digital broadcast signal transmitter forms FFT cascade interleaving in the frequency domain after its input data bit stream undergoes RS coding, convolutional interleaving, LDPC coding, symbol modulation, symbol rotation, and symbol interleaving The coded modulation data block is transformed into a discrete concatenated interleaved coded modulated data sample block in the time domain by IFFT, and the peak-to-average power ratio reduction unit with the lowest peak-to-average power ratio is selected through the peak-to-average power ratio adjustment unit in the time domain At the same time, the discrete concatenated interleaved coded modulation data sample block sends the corresponding generating 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, 64QAM and 256QAM, and the symbol constellation map mapping The method adopts Gray code mapping; the symbol rotation is realized by rotating the symbol constellation diagram by a certain angle. 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, and the rotation angle of the symbol constellation diagram of 64QAM is 11.25 degrees. The rotation angle of the diagram is 5.626 degrees, and the rotation angle of the symbol constellation diagram of 256QAM is 2.8125 degrees; the code element interleaving adopts the random interleaving method.

The FFT cascaded interleaved coded modulation data block consists of subcarriers. The length of the FFT concatenated interleaving coded modulation 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, 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.

The certain anti-fading mobile digital broadcasting signal transmitter uses the training sequence as the real part sequence of the complex training sequence, and uses the service index sequence as the imaginary part sequence of the complex training sequence to form discrete sample value blocks of the complex training sequence in the time domain, Repeat it four times continuously in the time domain to form discrete sample blocks of time domain embedding training sequence. 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 anti-fading mobile digital broadcast signal transmitter, the training sequence and service index sequence are composed of a series of 1 or -1, which have 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 mobile digital broadcasting signal transmitter.

The certain anti-fading mobile digital broadcasting signal transmitter directly superposes the peak-to-average power ratio reduction time-domain discrete concatenated interleaved coded modulation data sample block and the time-domain embedded training sequence discrete sample block to form a time-domain embedded training sequence peak-to-average reduction Power ratio time-domain discrete concatenated interleaved coded modulation data sample block, as a frame body; in the time domain embedding training sequence peak-to-average power ratio time domain discrete concatenated interleaved coded modulated data sample block, insert a cyclic prefix 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 At 2048, the corresponding C takes 1/16 of the size of K.

The certain anti-fading mobile digital broadcast signal transmitter employs 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.

The certain anti-fading mobile digital broadcast signal transmitter converts the baseband signal up to the carrier to form a radio frequency signal and transmits it to the wireless channel in the air.

The anti-fading mobile digital broadcast signal receiver detects and receives the radio frequency signal sent by the mobile digital broadcast signal 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 receive the baseband signal The processing includes joint iterative separation processing of the time-frequency domain 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. An anti-fading mobile digital broadcasting signal transmission method is characterized in that it comprises the following steps: 1) The anti-fading mobile digital broadcast signal 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 anti-fading mobile digital broadcast signal transmitter forms FFT cascade interleaving code in the frequency domain after its input data bit stream undergoes RS coding, convolutional interleaving, LDPC coding, symbol modulation, symbol rotation, and symbol interleaving Modulation data block, RS means Reed-Solomon, LDPC means Low Density Parity Check, and the length of FFT concatenated interleaving coding modulation data block is K; 3) The anti-fading mobile digital broadcasting signal transmitter uses 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 anti-fading mobile digital broadcast signal transmitter divides the time-domain discrete concatenated interleaved coded modulation data sample block into two blocks in sequence, the time-domain discrete concatenated 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 mobile digital broadcast signal transmitter 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

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

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 ${\mathrm{D.}}_{\mathrm{new}}=[\sqrt{1/2}({{\mathrm{D.}}^{*}}_1-{\mathrm{D.}}_2),{\mathrm{D.}}_2]$ , generating schema 12 as ${\mathrm{D.}}_{\mathrm{new}}=[\sqrt{1/2}({{\mathrm{D.}}^{*}}_1+{\mathrm{D.}}_2),\sqrt{1/2}({{\mathrm{D.}}^{*}}_1-{\mathrm{D.}}_2\left)\right],$ 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 anti-fading mobile digital broadcast signal 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 blocks of the sequence, the length of the discrete sample value blocks 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 anti-fading mobile digital broadcasting signal transmitter and business model information; 7) The anti-fading mobile digital broadcasting signal transmitter repeats the discrete sample blocks of the complex training sequence formed in the time domain for 4 consecutive times in the time domain to form a time domain embedded training sequence discrete sample block, and the time domain embedded training sequence is discrete The length of the sample value block and the length of the peak-to-average power ratio time-domain discrete concatenated interleaved coded modulation data sample block are equal in value, that is, K=4×X; 8) The anti-fading mobile digital broadcast signal transmitter directly superimposes the peak-to-average power ratio of the time-domain discrete cascaded interleaved coded modulation data sample block and the time-domain embedded training sequence discrete sample block to form a time-domain embedded training sequence to reduce the peak-to-average power Than the time-domain discrete cascaded interleaved coding modulated data sample block, as a frame body; 9) The anti-fading mobile digital broadcast signal transmitter uses the cyclic prefix as a guard interval, that is, inserts the frame header into the time domain, embeds the training sequence, reduces the peak-to-average power ratio, and time-domain discrete cascade interleaving codes the modulated data sample block, that is, the frame body, to form a signal frame , the length of the cyclic prefix is C; 10) The anti-fading mobile digital broadcast signal transmitter uses a square root raised cosine roll-off filter to shape the signal pulse of the signal frame; 11) The anti-fading mobile digital broadcast signal transmitter up-converts the baseband signal to the carrier to form a radio frequency signal and transmit it to the wireless channel in the air; 12) The anti-fading mobile digital broadcast signal receiver detects and receives the radio frequency signal sent by the anti-fading mobile digital broadcast signal 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 anti-fading mobile digital broadcasting signal 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 anti-fading mobile digital broadcasting signal transmitter, service index sequence, complex number training sequence takes One of 512, 1024, 2048. 3. The anti-fading mobile digital broadcast signal transmission method according to claim 2, characterized in that: said training sequence and service index sequence are composed of a series of 1 or -1, and have pseudo-random characteristics. 4. The anti-fading mobile digital broadcast signal 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 anti-fading mobile digital broadcasting signal transmission method of claim 1, it is characterized in that: said FFT cascading interleaving coding modulation data block is made up of subcarrier; When X gets 512, subcarrier number gets 2048, and the frequency of subcarrier The interval is 4KHz; when X is 1024, the number of subcarriers is 4096, and the frequency interval of subcarriers is 2KHz; when X is 2048, the number of subcarriers is 8192, and the frequency interval of subcarriers is 1KHz. 6. by the anti-fading mobile digital broadcast signal transmission method of claim 1, it is characterized in that: the length C value of the cyclic prefix is related to the X value; when X is 512, C is 1/4 of the 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. 7. by the anti-fading mobile digital broadcasting signal transmission method of claim 1, it is characterized in that: the encoding rate of described LDPC encoding is one of 1/4, 1/2, 5/8, 3/4 and 7/8 ; The symbol modulation is one of QPSK, 16QAM, 64QAM and 256QAM, and the symbol constellation mapping method adopts Gray code mapping; the symbol rotation is realized by rotating the symbol constellation at a certain angle, and the QPSK symbol constellation rotation The angle 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; the code element interleaving adopts the random interleaving method. 8. by the anti-fading mobile digital broadcasting signal transmission method of claim 1, it is characterized in that: the baseband signal receiving process that described anti-fading mobile digital broadcasting signal receiver carries out, one of the steps is signal frame header and signal frame body The time-frequency domain joint iterative separation process.

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