CN101778084B - Method for transmitting anti-fading wireless multi-media broadcast signal in single frequency network - Google Patents
Method for transmitting anti-fading wireless multi-media broadcast signal in single frequency network Download PDFInfo
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Abstract
The invention discloses a method for transmitting an anti-fading wireless multi-media broadcast signal in a single frequency network. In the method, the wireless multi-media broadcast signal is transmitted to an air wireless channel by a wireless multi-media broadcast transmitter in the single frequency network through the following steps: the multimedia data streams are processed by a central data manager; a network data manager carries out RS (Reed-Solomon) coding, convolution interleaving, LDPC (Low Density Parity Check) coding, code element modulating, constellation rotation and code element interleaving on bit streams; space-frequency coding modulation is carried out; discrete data sample value blocks in the time domain and embedded discrete sample value blocks of training sequences in the time domain are superposed to form frames; pulse shaping is carried out; up-conversion is carried out on a baseband signal to a carrier wave to form a radio-frequency signal to be transmitted to the air wireless channel; and a receiver terminal receives and processes the signal transmitted by the wireless multi-media broadcast transmitter in the single frequency network. The method has the advantages of short synchronous receipt time, channel fading resistance, large-range controllable multiple services in the single frequency network, etc.
Description
Technical field
The invention belongs to wireless communication field, relate more specifically to a kind of method for transmitting anti-fading wireless multi-media broadcast signal in single frequency network.
Background technology
At present, wireless videocast develops to the digitlization direction from simulation gradually.DTV radio transmission system, as the important component part of DTV radio broadcasting, its development of technologies, closely bound up with people's quality of life, and therefore received people's extensive concern especially.DTV radio 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 DTV radio broadcasting correlation technique, the emphasis of various countries' concern at present is that the DTV radio broadcasting how to pass under the environment for complex wave provides the implementation of reliable high-speed mobile cheaply.DTV radio transmission technology is the key technology of DTV wireless broadcast 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 of OFDM multi-carrier transmission technology has simple in structure; The availability of frequency spectrum is high, plurality of advantages such as becomes in the time of can resisting frequency selectivity and channel 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, digital television broadcasting.
In the practical communication environment, DTV wireless broadcast communication systematic function receives the influence of factors such as lock in time, clock jitter, channel fading, channel disturbance.DTV radio broadcasting signal transmission method is the key technology that realizes the broadcasting of reliable digit tv wireless.
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.In information sequence, embed redundancy symbol, the effect of channel coding technology through redundancy symbol reduces signal and in transmission course, makes a mistake, thereby improves the reliability of communication system.
Under multidiameter fading channel, can be through outer coding, interior coding, interweave and the cascade optimal design of modulation scheme reaches big as far as possible signal diversifying exponent number, so that in equaling or exceeding the symbol sebolic addressing of minimum free distance, obtain independent decline.Cascade different coding form can make full use of the advantage of different coding technology; Between coding and code element modulation, insert bit interleaver; Can be so that coding be relatively independent with modulated process and expand diversity order to different binary bits number from different multi-system symbolic numbers, thus make diversity order be improved significantly and under multidiameter fading channel, have the bit error performance of getting well.
Multiple antenna communication uses a plurality of (N
tIndividual) transmitting antenna and one or more (N
rIndividual) reception antenna carries out transfer of data, and it is through with N
tIndividual transmitting antenna sends different data and improves system throughput or improve the reliability of communication through send data redundantly.Transmit diversity is utilized in the redundant transmission of the enterprising line data of combination of space, frequency, time or these dimensions; Simple transmit diversity through at the transmitter and receiver place is handled, thereby the reliability that can improve the communication system data transmission makes communication system obtain stronger performance.Simultaneously, the networking model of employing SFN (that is, the same time of several transmitting stations is launched same signal to realize the reliable covering to certain coverage on same frequency) can improve the availability of frequency spectrum of radio multimedium broadcast transmission system greatly.
Utilizing DTV radio transmission system that may command multi-services such as free television broadcasting, paid television broadcasting, security information transmission, multimedia value-added service are provided is embodiments that DTV radio transmission of new generation system satisfies social needs.
Just be based on above background, the present invention is directed to the practical communication environment and propose a kind of method for transmitting anti-fading wireless multi-media broadcast signal in single frequency network, can satisfy the needs of SFN High Data Rate may command multi-service DTV radio transmission.
Desire is done more deep understanding to the patent background can be with reference to following documents and materials:
L.J.Cimini，“Analysis?and?simulation?of?a?digital?mobile?channel?usingorthogonal?frequency?division?multiplexing，”IEEE?Trans.Commun.，vol.COM-33，pp.665-675，July?1985.
R.V.Nee，R.Prasad.“OFDM?for?wireless?multimedia?communications”.Boston：Artech?House，2000.
A.R.S.Bahai?and?B.R.Saltzberg.“Multi-Carrier?Digital?Communications：Theory?and?Applications?of?OFDM”.Kluwer?Academic/Plenum，1999.
Y.Wu，S.Hirakawa，U.H.Reimers，and?J.Whitaker.“Overview?of?digitaltelevision?development，”Proceedings?of?the?IEEE，Special?Issueon?GlobalDigital?Television：Technology?and?Emerging?Services，pp.8-21，Jan.2006.
G.Caire，G.Taricco，E.Biglieri，“Bit-interleaved?coded?modulation，”IEEE?Trans.Information?Theory，vol.44，no.3，pp.927946，May?1998.
X.Li，A.Chindapol?and?J.A.Ritchey，“Bit-interleaved?coded?modulationwith?iterative?decoding?and?8PSK?signaling，”IEEE?Trans.Commun.，vol.50，pp.1250-1257，2002.
J.Hagenauer，“Rate-compatible?punctured?convolutional?codes?and?theirapplications，”IEEE?Trans.Commun.，vol.36，no.4，pp.389-400，April1988.
X.Li?and?J.A.Ritcey，“Bit-interleaved?coded?modulation?with?iterativedecoding，”IEEE?Commun.Lett.，vol.1，pp.169-171，Nov.1997.
A.Chindapol?and?J.A.Ritcey，“Design，analysis，and?performanceevaluation?for?BICM-ID?with?square?QAM?constellations?in?Rayleigh?fadingchannels，”IEEE?J.Select.Areas?Commun.，vol.19，no.5，pp.944-957，May?2001.
U.Wachsmann，R.Fischer，and?J.Huber，“Multilevel?codes：theoreticalconcepts?and?practical?design?rules，”IEEE?Trans.Inform.Theory，vol.45，no.5，pp.1361-1391，July?1999.
S.Benedetto，D.Divsalar，G.Montorsi，and F.Pollara，“Serialconcatenation?of?interleaved?codes：performance?analysis，design，anditerative?decoding，”IEEE?Trans.Inform.Theory，vol.44，no.3，pp.909-925，May?1998.
X.Giraud，E.Boutillon，J.C.Belfiore.“Algebraic?tools?to?buildmodulation?schemes?for?fading?channels，”IEEE?Trans.Commun.，vol.43，pp.938-952，May.1997.
J.Boutros，E.Viterbo.“Signal?space?diversity：A?power-andbandwidth-efficient?diversity?technique?for?the?Rayleigh?fadingchannel，”IEEE?Trans.Inform.Theory，vol.44，pp.1453-1467，July.1998.
Summary of the invention
The present invention is directed to the High Data Rate may command multi-service DTV radio transmission problem in the SFN, proposed a kind of method for transmitting anti-fading wireless multi-media broadcast signal in single frequency network.
A kind of method for transmitting anti-fading wireless multi-media broadcast signal in single frequency network that the present invention proposes is characterized in that wireless multi-media broadcast signal is sent to the on-air radio channel and receives the signal that processing radio multimedium broadcast transmitter end is sent by receiver end through following steps at the radio multimedium broadcast transmitter of SFN:
1) the centre data manager of SFN converts the multi-medium data media data processor of flowing through to data bit flow;
2) the network data management device of SFN will be imported the data bit RS coding (Reed-Solomon that flows through; RS), convolutional interleave, LDPC coding (Low Density Parity Check, LDPC), further on frequency domain, form the cascade interweaved coding modulation data piece of FFT (length (symbol numbers) of the cascade interweaved coding modulation data piece of FFT is K) after the code element modulation, constellation rotation, symbol interleave;
3) to adopt code check be that the cascade interweaved coding modulation data piece of FFT that 1 space-frequency coding device will form on frequency domain is modulated to form on each radio multimedium broadcast transmitter branch road in the SFN and emptyly frequently modulates the cascade interweaved coding modulation data piece of FFT (empty length (symbol numbers) of modulating the cascade interweaved coding modulation data piece of FFT frequently is K) to the network data management device of SFN, and the time synchronized of adjusting each radio multimedium broadcast transmitter branch road is all modulated the cascade interweaved coding modulation data piece of FFT frequently to sky at one time and handled to guarantee all transmitters in the network;
4) each radio multimedium broadcast transmitter in the SFN adopts IFFT (fast discrete Fourier inverse transformation) that sky is modulated the cascade interweaved coding modulation data piece of FFT frequently and is transformed to the empty cascade interweaved coding modulation data sample value of the time domain discrete piece of frequently modulating;
5) each radio multimedium broadcast transmitter in the SFN as the real part sequence of sequence of plural training, with the imaginary part sequence of operational indicator sequence as sequence of plural training, constitutes the discrete sample block (length of the discrete sample block of training sequence, operational indicator sequence, sequence of plural training all is X) of sequence of plural training with training sequence on time domain;
6) each radio multimedium broadcast transmitter in the SFN will repeat to form for 4 times time domain continuously in the discrete sample block of the sequence of plural training that constitutes on the time domain and embed training sequence discrete sample block (length that time domain embeds training sequence discrete sample block is K, K=4 * X) on time domain;
7) each radio multimedium broadcast transmitter in the SFN is modulated the cascade interweaved coding modulation data sample value of time domain discrete piece, time domain frequently with sky and is embedded training sequence discrete sample block and directly superpose and form the empty time domain of frequently modulating and embed the cascade interweaved coding modulation data piece of training sequence, as frame;
8) each radio multimedium broadcast transmitter in the SFN inserts the empty time domain of frequently modulating with Cyclic Prefix (length of Cyclic Prefix is C) as protection interval (frame head) and embeds the cascade interweaved coding modulation data piece of training sequence (frame), with the formation signal frame;
9) each radio multimedium broadcast transmitter in the SFN adopts square root raised cosine filter that the signal pulse of signal frame is shaped;
10) each radio multimedium broadcast transmitter in the SFN is with forming emission of radio frequency signals on baseband signal up-conversion to the carrier wave to the on-air radio channel;
11) receiver end in the SFN receives and handles the signal that each radio multimedium broadcast transmitter in the SFN is sent.
A kind of anti-fading single frequency network wireless multimedia broadcast signal transmission method according to above-mentioned is characterized in that: the centre data manager of SFN converts the multi-medium data media data processor of flowing through to data bit flow; The network data management device of SFN will be imported the data bit RS coding (Reed-Solomon that flows through; RS), convolutional interleave, LDPC coding (Low Density Parity Check, LDPC), further on frequency domain, form the cascade interweaved coding modulation data piece of FFT after the code element modulation, constellation rotation, symbol interleave; The network data management device of SFN carries out RS coding (Reed-Solomon to the input data bit flow; RS), convolutional interleave, LDPC (the Low Density Parity Check that encodes; LDPC), further on frequency domain, form the cascade interweaved coding modulation data piece of FFT after the code element modulation, constellation rotation, symbol interleave, the RS coding combines with convolutional interleave and has very strong antiburst error ability, wherein; The encoding rate of LDPC coding is in 1/4,1/2,5/8,3/4 and 7/8; Code element is modulated to a kind of among QPSK, 16QAM, 64QAM and the 256QAM, and symbol constellations figure mapping mode adopts the Gray code mapping, and the constellation rotation angle of QPSK symbol constellations is 22.5 degree; The constellation rotation angle of 16QAM symbol constellations is 11.25 degree; The constellation rotation angle of 64QAM symbol constellations is 5.626 degree, and the constellation rotation angle of 256QAM symbol constellations is 2.8125 degree, and symbol interleave adopts the random interleaving mode; It is that the cascade interweaved coding modulation data piece of FFT that 1 space-frequency coding device will form on frequency domain is modulated to form on each radio multimedium broadcast transmitter branch road in the SFN and emptyly frequently modulates the cascade interweaved coding modulation data piece of FFT (empty length (symbol numbers) of modulating the cascade interweaved coding modulation data piece of FFT frequently is K) that the network data management device of SFN adopts code check, and the time synchronized of adjusting each radio multimedium broadcast transmitter branch road is all modulated the cascade interweaved coding modulation data piece of FFT frequently to sky at one time and handled to guarantee all transmitters in the network; Have periodic time domain in the signal frame of each radio multimedium broadcast transmitter end in the SFN and embed training sequence discrete sample block; The length X of the training sequence of each radio multimedium broadcast transmitter end in the SFN is in 512,1024,2048; The length K (sub-carrier number) of the cascade interweaved coding modulation data piece of corresponding FFT 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 the cascade interweaved coding modulation data block length of FFT K size; The training sequence of each radio multimedium broadcast transmitter end in the SFN, operational indicator sequence are formed by a series of 1 or-1, have pseudo-random characteristics; Training sequence, the operational indicator sequence of each radio multimedium broadcast transmitter end in the SFN have orthogonality each other; Each different service index series of each radio multimedium broadcast transmitter end in the SFN is comprising and unique each system parameters and business model information of expressing the radio multimedium broadcast transmitter; The SFN receiver end receives handles the signal that each radio multimedium broadcast transmitter in the SFN is sent.
Characteristics of the present invention:
The present invention is the single-frequency network anti-fading signal diversifying transmission plan that a kind of spatial domain time-domain and frequency-domain mixes.The centre data manager of SFN converts the multi-medium data media data processor of flowing through to data bit flow; The network data management device of SFN will be imported the data bit RS coding (Reed-Solomon that flows through; RS), convolutional interleave, LDPC coding (Low Density Parity Check, LDPC), further on frequency domain, form the cascade interweaved coding modulation data piece of FFT after the code element modulation, constellation rotation, symbol interleave; It is that the cascade interweaved coding modulation data piece of FFT that 1 space-frequency coding device will form on frequency domain is modulated to form on each radio multimedium broadcast transmitter branch road in the SFN and emptyly frequently modulates the cascade interweaved coding modulation data piece of FFT (empty length (symbol numbers) of modulating the cascade interweaved coding modulation data piece of FFT frequently is K) that the network data management device of SFN adopts code check, and the time synchronized of adjusting each radio multimedium broadcast transmitter branch road is all modulated the cascade interweaved coding modulation data piece of FFT frequently to sky at one time and handled to guarantee all transmitters in the network.Each radio multimedium broadcast transmitter end in the SFN adopts the LDPC coding that the input data bit flow is carried out chnnel coding the error-correcting performance near shannon limit is provided.The code element modulation of each radio multimedium broadcast transmitter end in the SFN provides the signal diversifying effect with constellation rotation.Each radio multimedium broadcast transmitter end in the SFN adopts and encodes outward, interweaves, the cascade optimal design of interior coding, modulation, constellation rotation, interleaving scheme is carried out cascade interweaved coded modulation to the input data and improved signal diversifying exponent number and anti-interference noise error correcting capability; Make communication system under multidiameter fading channel, have good bit error performance, make communication system have anti-fading property the transmission environment background.Have periodic time domain in the signal frame of each radio multimedium broadcast transmitter end in the SFN and embed training sequence discrete sample block; Training sequence, the operational indicator sequence of each radio multimedium broadcast transmitter end in the SFN have pseudo-random characteristics; Training sequence, the operational indicator sequence of each radio multimedium broadcast transmitter end in the SFN have orthogonality each other; It is that discrete cascade interweaving encoding modulating data sample value piece, time domain by time domain embeds directly stack and forming of training sequence discrete sample block that the time domain of each radio multimedium broadcast transmitter end in the SFN embeds the cascade interweaved coding modulation data piece of training sequence, and these have guaranteed that the radio multimedium broadcasting receiver end in the SFN can realize fast and accurately frame synchronization, Frequency Synchronization, time synchronized, channel transfer characteristic estimation and phase noise and channel transfer characteristic are reliably followed the tracks of.Each radio multimedium broadcast transmitter end in the SFN inserts time domain with Cyclic Prefix at interval as protection and embeds the cascade interweaved coding modulation data piece of training sequence to form signal frame, can reduce the interference effect between the adjacent signals frame.Each different service index series of each radio multimedium broadcast transmitter end in the SFN is comprising and unique each system parameters and business model information of expressing the single frequency network wireless multimedia broadcast transmitter; The radio multimedium broadcast transmission system can satisfy social needs so that can provide may command multi-services such as free television broadcasting, paid television broadcasting, security information transmission, multimedia value-added service.The SFN receiver end receives handles the signal that each radio multimedium broadcast transmitter in the SFN is sent.A kind of anti-fading single frequency network wireless multimedia broadcast signal transmission method of the present invention have receive lock in time short, clock jitter is little, anti-SFN channel fading, anti-SFN channel disturbance, plurality of advantages such as large-scale SFN High Data Rate may command multi-service DTV radio transmission can be provided.
Description of drawings
Fig. 1 is the embodiment sketch map according to signal transmission between the transmitter and receiver of a kind of method for transmitting anti-fading wireless multi-media broadcast signal in single frequency network of the present invention.
Fig. 2 is the embodiment sketch map that forms according to signal frame in the signals transmission between the transmitter and receiver of a kind of method for transmitting anti-fading wireless multi-media broadcast signal in single frequency network of the present invention.
Fig. 3 is the embodiment sketch map according to the constellation rotation method that the QPSK code element is modulated, the 16QAM code element is modulated of the radio multimedium broadcast transmitter end of a kind of method for transmitting anti-fading wireless multi-media broadcast signal in single frequency network of the present invention.
Embodiment
To combine accompanying drawing that specific embodiment of the present invention is described in detail below.
The embodiment of signal transmission (supposing has N transmitter in the SFN) between the transmitter and receiver of a kind of method for transmitting anti-fading wireless multi-media broadcast signal in single frequency network that proposes according to the present invention; As shown in Figure 1, wireless multi-media broadcast signal is sent to the on-air radio channel and receives the signal that processing radio multimedium broadcast transmitter end is sent by receiver end through following steps at the radio multimedium broadcast transmitter end of SFN:
1) the centre data manager of SFN converts the multi-medium data media data processor of flowing through to data bit flow;
2) the network data management device of SFN will be imported the data bit RS coding (Reed-Solomon that flows through; RS), convolutional interleave (RS of radio multimedium broadcast transmitter end coding combines with convolutional interleave and has very strong antiburst error ability), LDPC (the Low Density Parity Check that encodes; LDPC) (the data bit of the radio multimedium broadcast transmitter end RS coding (Reed-Solomon that flows through; RS), the encoding rate of the LDPC behind convolutional interleave coding is in 1/4,1/2,5/8,3/4 and 7/8), the code element modulation (data bit of the radio multimedium broadcast transmitter end RS coding (Reed-Solomon that flows through; RS), the code element behind convolutional interleave, the LDPC coding is modulated to a kind of among QPSK, 16QAM, 64QAM and the 256QAM; The mapping of symbol constellations figure mapping mode employing Gray code), (the constellation rotation angle of QPSK symbol constellations is 22.5 degree to constellation rotation; The constellation rotation angle of 16QAM symbol constellations is 11.25 degree; The constellation rotation angle of 64QAM symbol constellations is 5.626 degree, and the constellation rotation angle of 256QAM symbol constellations is 2.8125 degree), (length (symbol numbers) of the cascade interweaved coding modulation data piece of FFT is K further on frequency domain, to form the cascade interweaved coding modulation data piece of FFT after the symbol interleave (symbol interleave adopt random interleaving mode); When X got 512, the length K (sub-carrier number) of the cascade interweaved coding modulation data piece of corresponding FFT got 2048, and the frequency interval of corresponding subcarrier is got 4KHz; When X got 1024, the length K (sub-carrier number) of the cascade interweaved coding modulation data piece of corresponding FFT got 4096, and the frequency interval of corresponding subcarrier is got 2KHz; When X got 2048, the length K (sub-carrier number) of the cascade interweaved coding modulation data piece of corresponding FFT got 8192, and the frequency interval of corresponding subcarrier is got 1KHz);
3) to adopt code check be that the cascade interweaved coding modulation data piece of FFT that 1 space-frequency coding device will form on frequency domain is modulated to form on each radio multimedium broadcast transmitter branch road in the SFN and emptyly frequently modulates the cascade interweaved coding modulation data piece of FFT (empty length (symbol numbers) of modulating the cascade interweaved coding modulation data piece of FFT frequently is K) to the network data management device of SFN, and the time synchronized of adjusting each radio multimedium broadcast transmitter branch road is all modulated the cascade interweaved coding modulation data piece of FFT frequently to sky at one time and handled to guarantee all transmitters in the network;
4) each radio multimedium broadcast transmitter in the SFN adopts IFFT (fast discrete Fourier inverse transformation) that sky is modulated the cascade interweaved coding modulation data piece of FFT frequently and is transformed to the empty cascade interweaved coding modulation data sample value of the time domain discrete piece of frequently modulating;
5) each radio multimedium broadcast transmitter in the SFN 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; On time domain, constitute the discrete sample block (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) of sequence of plural training;
6) each radio multimedium broadcast transmitter in the SFN will repeat to form for 4 times time domain continuously in the discrete sample block of the sequence of plural training that constitutes on the time domain and embed training sequence discrete sample block (length that time domain embeds training sequence discrete sample block is K, K=4 * X) on time domain;
7) each radio multimedium broadcast transmitter in the SFN is modulated the cascade interweaved coding modulation data sample value of time domain discrete piece, time domain frequently with sky and is embedded training sequence discrete sample block and directly superpose and form the empty time domain of frequently modulating and embed the cascade interweaved coding modulation data piece of training sequence, as frame;
8) (length of Cyclic Prefix is C to each radio multimedium broadcast transmitter in the SFN with Cyclic Prefix; When X got 512, corresponding C got 1/4 of the cascade interweaved coding modulation data block length of FFT K size; When X got 1024, corresponding C got 1/8 of the cascade interweaved coding modulation data block length of FFT K size; When X gets 2048, corresponding C get the cascade interweaved coding modulation data block length of FFT K size 1/16) as protection at interval (frame head) insert the empty time domain of frequently modulating and embed the cascade interweaved coding modulation data piece of training sequence (frame), to form signal frame;
9) each radio multimedium broadcast transmitter in the SFN adopts square root raised cosine filter that the signal pulse of signal frame is shaped;
10) each radio multimedium broadcast transmitter in the SFN is with forming emission of radio frequency signals on baseband signal up-conversion to the carrier wave to the on-air radio channel;
11) receiver end in the SFN receives and handles the signal that each radio multimedium broadcast transmitter in the SFN is sent.
According to the embodiment of signal frame formation (supposing has N transmitter in the SFN) in the signals transmission between the transmitter and receiver of a kind of method for transmitting anti-fading wireless multi-media broadcast signal in single frequency network of the present invention, as shown in Figure 2, practical implementation is following:
The centre data manager of SFN converts the multi-medium data media data processor of flowing through to data bit flow.
The network data management device of SFN will be imported the data bit RS coding (Reed-Solomon that flows through; RS), convolutional interleave, LDPC coding (Low Density Parity Check, LDPC), further on frequency domain, form the cascade interweaved coding modulation data piece of FFT after the code element modulation, constellation rotation, symbol interleave.
The cascade interweaved coding modulation data piece of the FFT of each radio multimedium broadcast transmitter in the SFN is made up of subcarrier.The length (symbol numbers) of the cascade interweaved coding modulation data piece of FFT is K; When X got 512, the length K (sub-carrier number) of the cascade interweaved coding modulation data piece of corresponding FFT got 2048, and the frequency interval of corresponding subcarrier is got 4KHz; When X got 1024, the length K (sub-carrier number) of the cascade interweaved coding modulation data piece of corresponding FFT got 4096, and the frequency interval of corresponding subcarrier is got 2KHz; When X got 2048, the length K (sub-carrier number) of the cascade interweaved coding modulation data piece of corresponding FFT got 8192, and the frequency interval of corresponding subcarrier is got 1KHz.
It is that the cascade interweaved coding modulation data piece of FFT that 1 space-frequency coding device will form on frequency domain is modulated to form on each radio multimedium broadcast transmitter branch road in the SFN and emptyly frequently modulates the cascade interweaved coding modulation data piece of FFT that the network data management device of SFN adopts code check, and the time synchronized of adjusting each radio multimedium broadcast transmitter branch road is all modulated the cascade interweaved coding modulation data piece of FFT frequently to sky at one time and handled to guarantee all transmitters in the network.
Each radio multimedium broadcast transmitter in the SFN adopts IFFT (fast discrete Fourier inverse transformation) that sky is modulated the cascade interweaved coding modulation data piece of FFT frequently and is transformed to the empty cascade interweaved coding modulation data sample value of the time domain discrete piece of frequently modulating.
Each radio multimedium broadcast transmitter in the SFN 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; On time domain, constitute the discrete sample block of sequence of plural training, on time domain, it is repeated 4 times continuously again and form time domain embedding training sequence discrete sample block.
The length of the discrete sample block of the training sequence of each radio multimedium broadcast transmitter in the SFN, operational indicator sequence, sequence of plural training all is X; X gets in 512,1024,2048; The length that time domain embeds training sequence discrete sample block is K, K=4 * X.
Training sequence, operational indicator sequence as each radio multimedium broadcast transmitter in the SFN 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 characteristic 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 service index series of each radio multimedium broadcast transmitter in the SFN is comprising and unique each system parameters and business model information of expressing each radio multimedium broadcast transmitter in the SFN.
Each radio multimedium broadcast transmitter in the SFN is modulated the cascade interweaved coding modulation data sample value of time domain discrete piece, time domain frequently with sky and is embedded training sequence discrete sample block and directly superpose and form the empty time domain of frequently modulating and embed the cascade interweaved coding modulation data piece of training sequence, as frame; Frequently modulate time domain at sky and embed and to insert Cyclic Prefix in the cascade interweaved coding modulation data piece of training sequence at interval, form signal frame as protection.
The length of the conduct protection Cyclic Prefix at interval of each radio multimedium broadcast transmitter in the SFN is C; When X got 512, corresponding C got 1/4 of the cascade interweaved coding modulation data block length of FFT K size; When X got 1024, corresponding C got 1/8 of the cascade interweaved coding modulation data block length of FFT K size; When X got 2048, corresponding C got 1/16 of the cascade interweaved coding modulation data block length of FFT K size.
Each radio multimedium broadcast transmitter in the SFN adopts square root raised cosine filter that the signal of signal frame is carried out pulse shaping.When X got 512, the rolloff-factor that corresponding signal to signal frame carries out the square root raised cosine filter of pulse shaping got 0.1; When X got 1024, the rolloff-factor that corresponding signal to signal frame carries out the square root raised cosine filter of pulse shaping got 0.05; When X got 2048, the rolloff-factor that corresponding signal to signal frame carries out the square root raised cosine filter of pulse shaping got 0.025.
Each radio multimedium broadcast transmitter in the SFN is with forming emission of radio frequency signals on baseband signal up-conversion to the carrier wave to the on-air radio channel.
Receiver end in the SFN receives handles the signal that each radio multimedium broadcast transmitter in the SFN is sent.
The embodiment of the QPSK code element modulation of the radio multimedium broadcast transmitter end of a kind of method for transmitting anti-fading wireless multi-media broadcast signal in single frequency network that proposes according to the present invention, the constellation rotation method of 16QAM code element modulation; As shown in Figure 3, the QPSK code element modulation of radio multimedium broadcast transmitter end, the symbol constellations figure mapping mode of 16QAM code element modulation adopt the Gray code mapping; The constellation rotation angle of QPSK symbol constellations is 22.5 degree, and the constellation rotation angle of 16QAM symbol constellations is 11.25 degree.
Combine accompanying drawing that specific embodiment of the present invention is specified above, but the present invention is not limited to the foregoing description, 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.
Claims (4)
1. method for transmitting anti-fading wireless multi-media broadcast signal in single frequency network is characterized in that wireless multi-media broadcast signal is sent to the on-air radio channel and is received by receiver end through following steps at the radio multimedium broadcast transmitter of SFN to handle the signal that radio multimedium broadcast transmitter end is sent:
1) the centre data manager of SFN converts the multi-medium data media data processor of flowing through to data bit flow;
2) the network data management device of SFN will be imported data bit and flow through and further on frequency domain, form the cascade interweaved coding modulation data piece of FFT after RS coding, convolutional interleave, LDPC coding, code element modulation, constellation rotation, the symbol interleave; Code element is modulated to a kind of among QPSK, 16QAM, 64QAM, the 256QAM; The symbol constellations figure mapping mode of code element modulation adopts the Gray code mapping; The constellation rotation angle of QPSK symbol constellations is 22.5 degree; The constellation rotation angle of 16QAM symbol constellations is 11.25 degree, and the constellation rotation angle of 64QAM symbol constellations is 5.626 degree, and the constellation rotation angle of 256QAM symbol constellations is 2.8125 degree; RS representes that Reed-Solomon is a Read-Solomon; LDPC representes that Low Density Parity Check is a low-density checksum, and FFT representes the fast discrete Fourier conversion, and the length of the cascade interweaved coding modulation data piece of FFT is K;
3) to adopt code check be that the cascade interweaved coding modulation data piece of FFT that 1 space-frequency coding device will form on frequency domain is modulated to form on each radio multimedium broadcast transmitter branch road in the SFN and emptyly frequently modulates the cascade interweaved coding modulation data piece of FFT to the network data management device of SFN, and the time synchronized of adjusting each radio multimedium broadcast transmitter branch road is all modulated the cascade interweaved coding modulation data piece of FFT frequently to sky at one time and handled to guarantee all transmitters in the network;
4) each radio multimedium broadcast transmitter in the SFN adopts IFFT that sky is modulated the cascade interweaved coding modulation data piece of FFT frequently to be transformed to and emptyly frequently to modulate the cascade interweaved coding modulation data sample value of time domain discrete piece, and IFFT representes the fast discrete Fourier inverse transformation;
5) each radio multimedium broadcast transmitter in the SFN 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; On time domain, constitute the discrete sample block of sequence of plural training, the length of the discrete sample block of training sequence, operational indicator sequence, sequence of plural training all is X;
6) each radio multimedium broadcast transmitter in the SFN will repeat 4 times continuously and form time domain embedding training sequence discrete sample block on time domain in the discrete sample block of the sequence of plural training that constitutes on the time domain, and the length that time domain embeds training sequence discrete sample block is 4 * X;
7) each radio multimedium broadcast transmitter in the SFN is modulated the cascade interweaved coding modulation data sample value of time domain discrete piece, time domain frequently with sky and is embedded training sequence discrete sample block and directly superpose and form the empty time domain of frequently modulating and embed the cascade interweaved coding modulation data piece of training sequence, as frame;
8) each radio multimedium broadcast transmitter in the SFN at interval is that frame head inserts and emptyly frequently modulates time domain to embed the cascade interweaved coding modulation data piece of training sequence be frame with Cyclic Prefix as protection, and to form signal frame, the length of Cyclic Prefix is C;
9) each radio multimedium broadcast transmitter in the SFN adopts square root raised cosine filter that the signal pulse of signal frame is shaped;
10) each radio multimedium broadcast transmitter in the SFN is with forming emission of radio frequency signals on baseband signal up-conversion to the carrier wave to the on-air radio channel;
11) receiver end in the SFN receives and handles the signal that each radio multimedium broadcast transmitter in the SFN is sent.
2. by a kind of method for transmitting anti-fading wireless multi-media broadcast signal in single frequency network of claim 1, it is characterized in that: the flow through encoding rate of the LDPC coding behind RS coding, the convolutional interleave of the data bit of the network data management device of said SFN is in 1/4,1/2,5/8,3/4 and 7/8.
3. by a kind of method for transmitting anti-fading wireless multi-media broadcast signal in single frequency network of claim 1, it is characterized in that: the data bit of the network data management device of the said SFN symbol interleave of carrying out after RS coding, convolutional interleave, LDPC coding, code element modulation, the constellation rotation of flowing through adopts the random interleaving mode.
4. press a kind of method for transmitting anti-fading wireless multi-media broadcast signal in single frequency network of claim 1; It is characterized in that: training sequence, the operational indicator sequence of each radio multimedium broadcast transmitter in the said SFN have pseudo-random characteristics, and training sequence, operational indicator sequence have orthogonality each other.
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| CN102255857B (en) * | 2011-08-22 | 2013-07-24 | 宁波大学 | Multimedia broadcast single-frequency network anti-fading mobile signal framing modulation method |
| CN102263735B (en) * | 2011-08-22 | 2013-09-25 | 宁波大学 | Method for transmitting wireless signals in digital broadcasting single frequency network |
| CN102263757B (en) * | 2011-08-22 | 2014-03-26 | 宁波大学 | Anti-fading mobile signal transmission method for digital broadcast single-frequency network |
| CN102255852B (en) * | 2011-08-22 | 2013-09-25 | 宁波大学 | Anti-fading wireless digital broadcast signal transmitting method |
| CN102255851A (en) * | 2011-08-22 | 2011-11-23 | 宁波大学 | Anti-fading wireless signal framing modulation method of multimedia broadcasting single frequency network |
| CN102263749B (en) * | 2011-08-22 | 2013-09-25 | 宁波大学 | Anti-fading mobile digital broadcast signal transmission method for single-frequency network |
| CN102263755B (en) * | 2011-08-22 | 2013-09-25 | 宁波大学 | Transmission method of mobile digital broadcast signals |
| CN102263730B (en) * | 2011-08-22 | 2013-09-25 | 宁波大学 | Mobile signal framing modulation method for multimedia broadcast single-frequency network |
| CN103763243A (en) * | 2014-01-13 | 2014-04-30 | 宁波大学 | Anti-fading mobile signal transmission method for digital broadcast single frequency network |
| CN103763237A (en) * | 2014-01-13 | 2014-04-30 | 宁波大学 | Framing modulation method for mobile signals of multimedia broadcast single frequency network |
| CN103763271A (en) * | 2014-01-13 | 2014-04-30 | 宁波大学 | Anti-fading mobile multimedia broadcast signal framing modulation method for single-frequency network |
| CN103763267A (en) * | 2014-01-13 | 2014-04-30 | 宁波大学 | Anti-noise mobile signal transmission method for digital broadcast |
| CN103763272A (en) * | 2014-01-13 | 2014-04-30 | 宁波大学 | Framing modulation method for wireless signals of multimedia broadcast |
| CN103763274A (en) * | 2014-01-13 | 2014-04-30 | 宁波大学 | Anti-fading framing modulation method for wireless signals of multimedia broadcast |
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