A kind of anti-noise wireless digital broadcast signal transmission method
Technical field
The invention belongs to wireless communication field, relate more specifically to a kind of anti-noise wireless digital broadcast signal transmission method.
Background technology
At present, television broadcasting develops to the digitlization direction gradually from simulation.Digital Television wireless digital broadcasting transmission system, as the important component part of Digital Television wireless digital broadcasting, its development of technologies, closely bound up with people's quality of life, and therefore be subjected to people's extensive concern especially.Digital Television wireless digital broadcasting correlation technique and related industry thereof are that development is very fast in the Communications And Computer field, the industry of good market prospect.On Digital Television anti-noise wireless digital broadcasting correlation technique, the emphasis of various countries' concern at present is that the Digital Television anti-noise wireless digital broadcasting how to pass under the environment for complex wave provides the implementation of reliable high-speed mobile cheaply.Anti-noise wireless digital broadcast signal transmitter transmission technology is the key technology of Digital Television anti-noise wireless digit broadcasting system, for whole system performance decisive role, is the object of everybody primary study.
Because the develop rapidly of Digital Signal Processing and integrated circuit technique, the system of OFDM (OFDM) technology realizes becoming more and more easier.Because OFDM multi-carrier transmission technology has simple in structure, the availability of frequency spectrum high plurality of advantages such as becomes and extremely everybody concern and obtain deep research and the extensive use in numerous areas such as Xdsl, wide-band mobile communication, wideband wireless local area network, the digital broadcasting of Digital Television anti-noise wireless in the time of can resisting frequency selectivity and channel.
The higher peak-to-average power ratio (PAPR) of ofdm signal has very high requirement to the range of linearity of amplifier and digital to analog converter, if the system linearity scope can not satisfy the variation of signal, then can cause signal distortion, signal spectrum is changed, thereby cause the orthogonality between the subchannel to be destroyed, produce the phase mutual interference, make system performance degradation.Therefore, the solution that must consider how to reduce the probability of occurrence of big peak power signal in the ofdm signal and reduce the nonlinear distortion influence.
Chnnel coding is the important component part of digital communication system.Along with the develop rapidly of modern information technologies, channel coding technology has become the indispensable technology in modern communications field.Embed redundancy symbol in information sequence, the effect of channel coding technology by redundancy symbol reduces signal and makes a mistake in transmission course, thereby improves the reliability of communication system.(Low Density Parity Check, LDPC) sign indicating number is a kind of in noise transmission channel transmission information and carry out the error correcting code of forward error correction (FEC, Forward Error Correction) to low-density checksum.LDPC coding be a kind of message transmission rate that can make near theoretical maximum, i.e. the encoding scheme of shannon limit.
In the practical communication environment, Digital Television wireless digital broadcasting communication system performance is subjected to the influence of factors such as lock in time, clock jitter, channel fading, channel disturbance.Anti-noise wireless digital broadcast signal transmitter transmission method is the key technology that realizes the digital broadcasting of reliable digit TV anti-noise wireless.
Utilizing Digital Television wireless digital broadcasting transmission system to provide free television broadcasting, paid television broadcasting, security information transmission, multimedia value-added service etc. can control multi-service is the embodiment that Digital Television wireless digital broadcasting transmission system of new generation satisfies social needs.
Just be based on above background, the present invention is directed to the practical communication environment and propose a kind of anti-noise wireless digital broadcast signal transmission method, can satisfy the needs that High Data Rate can be controlled multi-service Digital Television anti-noise wireless digital broadcast transmission.
Desire is done more deep understanding to the patent background can be with reference to following documents and materials:
R.V.Nee,R.Prasad.“OFDM?for?wireless?multimedia?communications”.Boston:Artech?House,2000.
Y.Wu,S.Hirakawa,U.H.Reimers,and?J.Whitaker.“Overview?of?digital?television?development,”Proceedings?of?the?IEEE,Special?Issue?on?Global?Digital?Television:Technology?and?Emerging?Services,pp.8-21,Jan.2006.
M.S.Richer,G.Reitmeier,T.Gurley,G.A.Jones,J.Whitaker,and?R.Rast.“The?ATSC?digital?television?system,”Proceedings?of?the?IEEE,Special?Issue?on?Global?Digital?Television:Technology?and?Emerging?Services,pp.37-43,Jan.2006.
U.Ladebusch?and?C.A.Liss.“Terrestrial?DVB(DVB-T):A?broadcast?technology?for?stationary?portable?and?mobile?use,”Proceedings?of?the?IEEE,Special?Issue?on?Global?Digital?Television:Technology?and?Emerging?Services,pp.183-194,Jan.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-cyclic?low-density?parity-check?codes,”IEEE?Trans.Commun.,vol.54,no.1,pp.71-81,Jan.2006.
Summary of the invention
The present invention is directed to High Data Rate and can control multi-service Digital Television anti-noise wireless digital broadcasting problem, proposed a kind of anti-noise wireless digital broadcast signal transmission method.
A kind of anti-noise wireless digital broadcast signal transmission method that the present invention proposes is characterized in that it comprises the following steps:
1) anti-noise wireless digital broadcast signal transmitter 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) anti-noise wireless digital broadcast signal transmitter is coded in the input data bit of oneself LDPC that flows through on the frequency domain and forms the FFT coded data block, and FFT represents the fast discrete Fourier conversion, and the length of FFT coded data block is K;
3) anti-noise wireless digital broadcast signal transmitter adopts IFFT that the FFT coded data block is transformed to time domain discrete coded data sample value piece D
Total, IFFT represents the fast discrete Fourier inverse transformation;
4) anti-noise wireless digital broadcast signal transmitter is divided equally into two with time domain discrete coded data sample value piece in order, the sub-piece D of time domain discrete coded data sample value
1With the sub-piece D of time domain discrete coded data sample value
2, D
Total=[D
1, D
2];
5) anti-noise wireless digital broadcast signal transmitter passes through the peak-to-average power ratio adjustment unit to the sub-piece D of time domain discrete coded data sample value
1, the sub-piece D of time domain discrete coded data sample value
2Carry out that signal adds, subtracts, conjugate operation is handled and synthetic new time domain discrete coded data sample value piece D again
New, new time domain discrete coded data sample value piece D
NewAdopt following generate pattern to obtain, generate pattern 1 is D
New=[D
1, D
2], generate pattern 2 is
Generate pattern 3 is
Generate pattern 4 is
Generate pattern 5 is
Generate pattern 6 is
Generate pattern 7 is D
New=[D
* 1, D
2], generate pattern 8 is
Generate pattern 9 is
Generate pattern 10 is
Generate pattern 11 is
Generate pattern 12 is
Compare the synthetic time domain discrete coded data sample value piece D of 12 kinds of generate patterns
New, choose wherein have a minimum peak-to-average power ratio peak-to-average power ratio time domain discrete coded data sample value piece falls
And peak-to-average power ratio time domain discrete coded data sample value piece will fall
The corresponding generate pattern information that adopts send to the operational indicator sequence unit be set, wherein, D
* 1Expression is to the sub-piece D of time domain discrete coded data sample value
1Each time domain discrete coded data sample value carry out that conjugate operation is handled and the sub-piece of time domain discrete coded data sample value that obtains;
6) anti-noise wireless digital broadcast signal transmitter with training sequence as the real part sequence of sequence of plural training, the operational indicator sequence is arranged the set operational indicator sequence in unit as the imaginary part sequence of sequence of plural training, constitute the discrete sample block of sequence of plural training in time domain, the length of the discrete sample block of training sequence, operational indicator sequence, 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 anti-noise wireless digital broadcast signal transmitter;
7) discrete sample block of the anti-noise wireless digital broadcast signal transmitter sequence of plural training that will constitute in time domain repeats to form time domains 4 times continuously and embeds training sequence discrete sample block on time domain, time domain embeds the length and the length numerically equal of falling peak-to-average power ratio time domain discrete coded data sample value piece, i.e. K=4 * X of training sequence discrete sample block;
8) anti-noise wireless digital broadcast signal transmitter will fall peak-to-average power ratio time domain discrete coded data sample value piece, time domain and embed training sequence discrete sample block and directly superpose and form time domain and embed training sequence and fall peak-to-average power ratio time domain discrete coded data sample value piece, as frame;
9) anti-noise wireless digital broadcast signal transmitter at interval is that frame head inserts time domain and embeds training sequence to fall peak-to-average power ratio time domain discrete coded data sample value piece be frame with Cyclic Prefix as protection, and to form signal frame, the length of Cyclic Prefix is C;
10) anti-noise wireless digital broadcast signal transmitter adopts square root raised cosine filter that the signal pulse of signal frame is shaped;
11) anti-noise wireless digital broadcast signal transmitter forms emission of radio frequency signals to the on-air radio channel with the baseband signal up-conversion to carrier wave;
12) the anti-noise wireless digital broadcasting signal receiver detect to receive radiofrequency signal that the wireless digital broadcasting signal transmitter sends 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.
Anti-noise wireless digital broadcast signal transmission method according to above-mentioned is characterized in that: anti-noise wireless digital broadcast signal transmitter fall peak-to-average power ratio time domain discrete coded data sample value piece by the signal that the sub-piece of time domain discrete coded data sample value is undertaken by specific 12 kinds of generate patterns add, subtract, conjugate operation is handled and synthetic again; Have periodic time domain in the signal frame of anti-noise wireless digital broadcast signal transmitter and embed training sequence discrete sample block; The length X of the training sequence of anti-noise wireless digital broadcast signal transmitter is in 512,1024,2048, the length K of corresponding FFT data block is respectively 2048,4096,8192, the frequency interval of corresponding subcarrier is respectively 4KHz, 2KHz, 1KHz, and corresponding circulating prefix-length C is respectively 1/4,1/8,1/16 of FFT data block length K size; The training sequence of anti-noise wireless digital broadcast signal transmitter, operational indicator sequence are formed by a series of 1 or-1, have pseudo-random characteristics; Training sequence, the operational indicator sequence of anti-noise wireless digital broadcast signal transmitter have orthogonality each other; Each different operational indicator sequence of anti-noise wireless digital broadcast signal transmitter is comprising and unique each system parameters and business model information of expressing anti-noise wireless digital broadcast signal transmitter; The encoding rate that the input data are carried out LDPC coding is in 1/4,1/2,5/8,3/4 and 7/8.The anti-noise wireless digital broadcasting signal receiver can take full advantage of the Cyclic Prefix characteristic of signal frame and the architectural characteristic of signal frame is carried out baseband signal reception processing, handles comprising the time domain and frequency domain combined alternate analysis to signal frame head and signal frame body.
Characteristics of the present invention:
The present invention is the transmission plan that a kind of time-domain and frequency-domain mixes.Generate pattern of falling peak-to-average power ratio time domain discrete coded data sample value piece of the present invention and have a minimum peak-to-average power ratio peak-to-average power ratio time domain discrete coded data sample value piece choosing method falls, but the very high big peak power signal probability of the maximum peak power that not only can take full advantage of ofdm signal is very low, the real part (or imaginary part) of the ofdm signal when number of sub carrier wave is big is the characteristic of multiple Gaussian random process and whose amplitude obeys Rayleigh distribution, the amount of information of the required extra transmission of adopting of generate pattern is little, be easy to handle the primary signal of recovering to obtain ofdm signal at receiver end, the orthogonal property that can not destroy sub-carrier signal simultaneously can not produce extra nonlinear distortion yet.Have periodic time domain in the signal frame of anti-noise wireless digital broadcast signal transmitter and embed training sequence discrete sample block, the training sequence of anti-noise wireless digital broadcast signal transmitter, the operational indicator sequence has pseudo-random characteristics, the training sequence of anti-noise wireless digital broadcast signal transmitter, the operational indicator sequence has orthogonality each other, it is by falling peak-to-average power ratio time domain discrete coded data sample value piece that peak-to-average power ratio time domain discrete coded data sample value piece falls in the time domain embedding training sequence of anti-noise wireless digital broadcast signal transmitter, time domain embeds training sequence discrete sample block and directly superposes and form, and these have guaranteed that the anti-noise wireless digital broadcasting signal receiver can realize frame synchronization fast and accurately, Frequency Synchronization, time synchronized, channel transfer characteristic is estimated, and phase noise and channel transfer characteristic reliably followed the tracks of.Cyclic Prefix is inserted time domain embedding training sequence at interval as protection fall peak-to-average power ratio time domain discrete coded data sample value piece to form signal frame, can reduce the interference effect between the adjacent signals frame.Adopt the LDPC coding that the input data are carried out chnnel coding error-correcting performance near shannon limit is provided.Each different operational indicator sequence of anti-noise wireless digital broadcast signal transmitter is comprising and unique each system parameters and business model information of expressing anti-noise wireless digital broadcast signal transmitter, Digital Television anti-noise wireless digital broadcasting transmission system can satisfy social needs so that can provide free television broadcasting, paid television broadcasting, security information transmission, multimedia value-added service etc. can control multi-service.Transmission method of the present invention has the equal power ratio of ebb, lock in time is short, clock jitter is little, anti-channel fading, anti-channel disturbance, can provide High Data Rate can control plurality of advantages such as multi-service Digital Television anti-noise wireless digital broadcast transmission.
Description of drawings
Fig. 1 is the embodiment schematic diagram according to signal transmission between certain transmitter and receiver of anti-noise wireless digital broadcast signal transmission method of the present invention.
Fig. 2 is the embodiment schematic diagram that forms according to signal frame in the signals transmission between certain transmitter and receiver of anti-noise wireless digital broadcast signal transmission method of the present invention.
Embodiment
Below in conjunction with accompanying drawing specific embodiments of the invention are described in detail.
The embodiment schematic diagram of signal transmission between certain transmitter and receiver of the anti-noise wireless digital broadcast signal transmission method that proposes according to the present invention as shown in Figure 1, follows these steps to carry out:
1) this certain anti-noise wireless digital broadcast signal transmitter 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) this certain anti-noise wireless digital broadcast signal transmitter is coded in the input data bit of oneself LDPC that flows through on the frequency domain and forms the FFT coded data block, and FFT represents the fast discrete Fourier conversion, and the length of FFT coded data block is K; The encoding rate that the input data are carried out LDPC coding is in 1/4,1/2,5/8,3/4 and 7/8;
3) this certain anti-noise wireless digital broadcast signal transmitter adopts IFFT that the FFT coded data block is transformed to time domain discrete coded data sample value piece D
Total, IFFT represents the fast discrete Fourier inverse transformation;
4) this certain anti-noise wireless digital broadcast signal transmitter is divided equally into two with time domain discrete coded data sample value piece in order, the sub-piece D of time domain discrete coded data sample value
1With the sub-piece D of time domain discrete coded data sample value
2, D
Total=[D
1, D
2];
5) this certain anti-noise wireless digital broadcast signal transmitter passes through the peak-to-average power ratio adjustment unit to the sub-piece D of time domain discrete coded data sample value
1, the sub-piece D of time domain discrete coded data sample value
2Carry out that signal adds, subtracts, conjugate operation is handled and synthetic new time domain discrete coded data sample value piece D again
New, new time domain discrete coded data sample value piece D
NewAdopt following generate pattern to obtain, generate pattern 1 is D
New=[D
1, D
2], generate pattern 2 is
Generate pattern 3 is
Generate pattern 4 is
Generate pattern 5 is
Generate pattern 6 is
Generate pattern 7 is D
New=[D
* 1, D
2], generate pattern 8 is
Generate pattern 9 is
Generate pattern 10 is
Generate pattern 11 is
Generate pattern 12 is
Compare the synthetic time domain discrete coded data sample value piece D of 12 kinds of generate patterns
New, choose wherein have a minimum peak-to-average power ratio peak-to-average power ratio time domain discrete coded data sample value piece falls
And peak-to-average power ratio time domain discrete coded data sample value piece will fall
The corresponding generate pattern information that adopts send to the operational indicator sequence unit be set, wherein, D
* 1Expression is to the sub-piece D of time domain discrete coded data sample value
1Each time domain discrete coded data sample value carry out that conjugate operation is handled and the sub-piece of time domain discrete coded data sample value that obtains;
6) this certain anti-noise wireless digital broadcast signal transmitter is with the real part sequence of training sequence as sequence of plural training, the operational indicator sequence is arranged the set operational indicator sequence in unit as the imaginary part sequence of sequence of plural training, constitute the discrete sample block of sequence of plural training in time domain, training sequence, the operational indicator sequence, the length of the discrete sample block of sequence of plural training all is X, the operational indicator sequence is comprising and unique each system parameters and business model information of expressing anti-noise wireless digital broadcast signal transmitter, and X gets 512,1024, in 2048 one;
7) discrete sample block of this certain anti-noise wireless digital broadcast signal transmitter sequence of plural training that will constitute in time domain repeats to form time domains 4 times continuously and embeds training sequence discrete sample block on time domain, time domain embeds the length and the length numerically equal of falling peak-to-average power ratio time domain discrete coded data sample value piece, i.e. K=4 * X of training sequence discrete sample block; When X got 512, K got 2048, and the frequency interval of corresponding subcarrier is got 4KHz; When X got 1024, K got 4096, and the frequency interval of corresponding subcarrier is got 2KHz; When X got 2048, K got 8192, and the frequency interval of corresponding subcarrier is got 1KHz;
8) this certain anti-noise wireless digital broadcast signal transmitter will fall peak-to-average power ratio time domain discrete coded data sample value piece, time domain and embed training sequence discrete sample block and directly superpose and form time domain and embed training sequence and fall peak-to-average power ratio time domain discrete coded data sample value piece, as frame;
9) this certain anti-noise wireless digital broadcast signal transmitter at interval is that frame head inserts time domain and embeds training sequence to fall peak-to-average power ratio time domain discrete coded data sample value piece be frame with Cyclic Prefix as protection, and to form signal frame, the length of Cyclic Prefix is C; 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;
10) this certain anti-noise wireless digital broadcast signal transmitter adopts square root raised cosine filter that the signal pulse of signal frame is shaped;
11) this certain anti-noise wireless digital broadcast signal transmitter forms emission of radio frequency signals to the on-air radio channel with the baseband signal up-conversion to carrier wave;
12) this certain anti-noise wireless digital broadcasting signal receiver detects and receives radiofrequency signal that wireless digital broadcasting signal transmitter sends and its down-conversion is formed baseband signal, utilize the Cyclic Prefix characteristic of signal frame and the architectural characteristic of signal frame to carry out baseband signal reception processing, handle comprising the time domain and frequency domain combined alternate analysis to signal frame head and signal frame body.
According to the embodiment schematic diagram that signal frame in the signals transmission between certain transmitter and receiver of anti-noise wireless digital broadcast signal transmission method of the present invention forms, as shown in Figure 2, specifically implement as follows:
This certain anti-noise wireless digital broadcast signal transmitter 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.
This certain anti-noise wireless digital broadcast signal transmitter is coded in the input data bit of oneself LDPC that flows through on the frequency domain and forms the FFT coded data block, through IFFT it is transformed to the discrete coded data sample value piece of time domain again, generates by the peak-to-average power ratio adjustment unit and choose the peak-to-average power ratio time domain discrete coded data sample value piece that falls that wherein has minimum peak-to-average power ratio and simultaneously the generate pattern information of the corresponding employing of institute is sent to the operational indicator sequence unit is set.
The FFT data block is made up of subcarrier.The length of FFT data block is K; When X got 512, corresponding K got 2048, and the frequency interval of corresponding subcarrier is got 4KHz; When X got 1024, corresponding K got 4096, and the frequency interval of corresponding subcarrier is got 2KHz; When X got 2048, corresponding K got 8192, and the frequency interval of corresponding subcarrier is got 1KHz.
This certain anti-noise wireless digital broadcast signal transmitter with training sequence as the real part sequence of sequence of plural training, with the imaginary part sequence of operational indicator sequence as sequence of plural training, in the discrete sample block of time domain formation sequence of plural training, on time domain, it is repeated 4 times continuously again and form time domains embedding training sequence discrete sample block.The length of the discrete sample block of training sequence, operational indicator sequence, sequence of plural training all is X, and X gets in 512,1024,2048, and the length that time domain embeds training sequence discrete sample block is K, K=4 * X.
Training sequence, operational indicator sequence as anti-noise wireless digital broadcast signal transmitter are formed by a series of 1 or-1, have pseudo-random characteristics, and training sequence, operational indicator sequence have orthogonality each other.The training sequence that satisfies above-mentioned feature can be by realizing as one group of displacement m sequence of a kind of specific type of pseudo-random number sequence with as the walsh sequence of orthogonal sequence, Hadamard sequences or by the orthogonal sequence that other modes produce.Each different operational indicator sequence is comprising and unique each system parameters and business model information of expressing anti-noise wireless digital broadcast signal transmitter.
This certain anti-noise wireless digital broadcast signal transmitter will fall peak-to-average power ratio time domain discrete coded data sample value piece, time domain and embed training sequence discrete sample block and directly superpose and form time domain and embed training sequence and fall peak-to-average power ratio time domain discrete coded data sample value piece, as frame; Embed training sequence in time domain and fall and insert Cyclic Prefix in the peak-to-average power ratio time domain discrete coded data sample value piece as protection at interval, form signal frame.Length as protection Cyclic Prefix at interval is C; When X got 512, corresponding C got 1/4 of K size; When X got 1024, corresponding C got 1/8 of K size; When X got 2048, corresponding C got 1/16 of K size.
This certain anti-noise wireless digital broadcast signal transmitter adopts square root raised cosine filter that the signal of signal frame is carried out pulse shaping.When X got 512, the corresponding signal to signal frame carried out the rolloff-factor of the square root raised cosine filter of pulse shaping and gets 0.1; When X got 1024, the corresponding signal to signal frame carried out the rolloff-factor of the square root raised cosine filter of pulse shaping and gets 0.05; When X got 2048, the corresponding signal to signal frame carried out the rolloff-factor of the square root raised cosine filter of pulse shaping and gets 0.025.
This certain anti-noise wireless digital broadcast signal transmitter forms emission of radio frequency signals to the on-air radio channel with the baseband signal up-conversion to carrier wave.
This certain anti-noise wireless digital broadcasting signal receiver detects and receives radiofrequency signal that wireless digital broadcasting signal transmitter sends and its down-conversion is formed baseband signal, utilize the Cyclic Prefix characteristic of signal frame and the architectural characteristic of signal frame to carry out baseband signal reception processing, handle comprising the time domain and frequency domain combined alternate analysis to signal frame head and signal frame body.
By reference to the accompanying drawings specific embodiments of the invention are had been described in detail above, but the present invention is not limited to above-described embodiment, under the spirit and scope situation of the claim that does not break away from the application, those skilled in the art can make various modifications or remodeling.