CN102255850A - Wireless multimedia broadcast signal framing modulation method for single frequency network - Google Patents

Abstract

The invention discloses a wireless multimedia broadcast signal framing modulation method for a single frequency network, which is a time domain/frequency domain/space domain hybrid framing modulation scheme. The wireless multimedia broadcast signal framing modulation method for the single frequency network has the advantages of low peak-to-average power ratio, short synchronization time, anti-channel interference performance, multi-service controllability and the like.

Description

A kind of single frequency network wireless multimedia broadcast signal framing modulator approach

Technical field

The invention belongs to wireless communication field, relate more specifically to a kind of single frequency network wireless multimedia broadcast signal framing modulator approach.

Background technology

Digital Television radio multimedium broadcast transmission system, as the important component part of Digital Television radio multimedium 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 radio multimedium 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 radio multimedium broadcasting correlation technique, the emphasis of various countries' concern at present is that the Digital Television radio multimedium broadcasting how to pass under the environment for complex wave provides the implementation of reliable high-speed mobile cheaply.Wireless multi-media broadcast signal transmitter framing modulation technique is the key technology of Digital Television wireless multimedia 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 of 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 broadcasting of Digital Television radio multimedium in the time of can resisting frequency selectivity and channel.

Peak-to-average power ratio (PAPR) pair amplifier that ofdm signal is higher and the range of linearity of digital to analog converter have very high requirement, 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.

The networking model of employing single frequency network (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 Digital Television radio multimedium broadcast transmission system greatly.In actual single frequency network communication environment, Digital Television radio multimedium broadcast communication system performance is subjected to the influence of factors such as lock in time, clock jitter, channel fading, channel disturbance.Single frequency network wireless multimedia broadcast signal transmitter framing modulator approach is to realize the key technology of reliable digit TV monochromatic network radio multimedium broadcasting.

Utilizing digital television single-frequency network radio multimedium broadcast 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 Digital Television radio multimedium broadcast 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 single frequency network wireless multimedia broadcast signal framing modulator approach, can satisfy the needs of High Data Rate may command multi-service digital television single-frequency network radio multimedium broadcast transmitted.

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.

Summary of the invention

The present invention is directed to High Data Rate may command multi-service digital television single-frequency network radio multimedium broadcast issue, proposed a kind of single frequency network wireless multimedia broadcast signal framing modulator approach.

A kind of single frequency network wireless multimedia broadcast signal framing modulator approach that the present invention proposes is characterized in that it comprises the following steps:

1) the network data management device of single frequency network will be imported data bit flow and form the FFT data block on frequency domain, and FFT represents the fast discrete Fourier conversion, and the length of FFT data block is K;

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

3) each wireless multi-media broadcast signal transmitter in the single frequency network adopts IFFT that sky is modulated the FFT data block frequently and is transformed to the empty time domain discrete data sample block D that frequently modulates _Total, IFFT represents the fast discrete Fourier inverse transformation;

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

5) each wireless multi-media broadcast signal transmitter in the single frequency network is modulated the sub-piece D of time domain discrete data sample by the peak-to-average power ratio adjustment unit frequently to sky ₁, the empty sub-piece D of time domain discrete data sample that frequently modulates ₂Carry out that signal adds, subtracts, conjugate operation is handled and the synthetic new again empty time domain discrete data sample block D that frequently modulates _New, the new empty time domain discrete data sample block D that frequently modulates _NewAdopt following generate pattern to obtain, generate pattern 1 is D _New=[D ₁, D ₂], generate pattern 2 is $D_{\mathrm{new}}=[D_1,\sqrt{1/2}(D_1+D_2)],$ Generate pattern 3 is $D_{\mathrm{new}}=[D_1,\sqrt{1/2}(D_1-D_2)],$ Generate pattern 4 is $D_{\mathrm{new}}=[\sqrt{1/2}(D_1+D_2),D_2],$ Generate pattern 5 is $D_{\mathrm{new}}=[\sqrt{1/2}(D_1-D_2),D_2],$ Generate pattern 6 is $D_{\mathrm{new}}=[\sqrt{1/2}(D_1+D_2),\sqrt{1/2}(D_1-D_2)],$ Generate pattern 7 is D _New=[D ^* ₁, D ₂], generate pattern 8 is $D_{\mathrm{new}}=[{D^{*}}_1,\sqrt{1/2}({D^{*}}_1+D_2)],$ Generate pattern 9 is $D_{\mathrm{new}}=[{D^{*}}_1,\sqrt{1/2}({D^{*}}_1-D_2)],$ Generate pattern 10 is $D_{\mathrm{new}}=\left[\sqrt{1/2}({D^{*}}_1+D_2){,D}_2\right],$ Generate pattern 11 is $D_{\mathrm{new}}=[\sqrt{1/2}({D^{*}}_1-D_2),D_2],$ Generate pattern 12 is $D_{\mathrm{new}}=[\sqrt{1/2}({D^{*}}_1+D_2),\sqrt{1/2}({D^{*}}_1-D_2)],$ Relatively 12 kinds of synthetic empty frequencies of generate pattern are modulated time domain discrete data sample block D _New, choose the empty frequency of peak-to-average power ratio that falls that wherein has minimum peak-to-average power ratio and modulate time domain discrete data sample block

And the empty time domain discrete data sample block of frequently modulating of peak-to-average power ratio will be fallen

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

6) each wireless multi-media broadcast signal transmitter in the single frequency network with training sequence as the real part sequence of sequence of plural training, the operational indicator sequence is provided with the imaginary part sequence of the set operational indicator sequence in unit as sequence of plural training, on time domain, constitute the discrete sample block of sequence of plural training, 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 each wireless multi-media broadcast signal transmitter in the single frequency network;

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

8) each wireless multi-media broadcast signal transmitter in the single frequency network will fall the empty time domain discrete data sample block, time domain of frequently modulating of peak-to-average power ratio and embed training sequence discrete sample block and directly superpose and form time domain and embed training sequence and fall that peak-to-average power ratio is empty frequently modulates time domain discrete data sample block, as frame;

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

10) each wireless multi-media broadcast signal transmitter in the single frequency network adopts square root raised cosine filter that the signal pulse of signal frame is shaped;

11) each wireless multi-media broadcast signal transmitter in the single frequency network with the baseband signal up-conversion to carrier wave.

Single frequency network wireless multimedia broadcast signal framing modulator approach according to above-mentioned is characterized in that: each wireless multi-media broadcast signal transmitter in the single frequency network fall that peak-to-average power ratio is empty modulates that time domain discrete data sample block modulates frequently by sky that the signal that the sub-piece of time domain discrete data sample undertakies by specific 12 kinds of generate patterns adds, subtracts, conjugate operation is handled frequently and synthetic again; Have periodic time domain in the signal frame of each wireless multi-media broadcast signal transmitter in the single frequency network and embed training sequence discrete sample block; The length X of the training sequence of each wireless multi-media broadcast signal transmitter in the single frequency network is in 512,1024,2048, corresponding empty length K of modulating the FFT data block frequently is respectively 2048,4096,8192, the frequency interval of corresponding subcarrier is respectively 4KHz, 2KHz, 1KHz, and corresponding circulating prefix-length C is respectively empty 1/4,1/8,1/16 of the FFT data block length K size of frequently modulating; The training sequence of each wireless multi-media broadcast signal transmitter in the single frequency network, operational indicator sequence are formed by a series of 1 or-1, have pseudo-random characteristics; Training sequence, the operational indicator sequence of each wireless multi-media broadcast signal transmitter in the single frequency network have orthogonality each other; Each different operational indicator sequence of each wireless multi-media broadcast signal transmitter in the single frequency network is comprising and unique each system parameters and business model information of expressing each wireless multi-media broadcast signal transmitter in the single frequency network; The code check of space-frequency coding device is 1.

Characteristics of the present invention:

The present invention is the framing modulation scheme that mix in a kind of time-domain and frequency-domain spatial domain.The empty generate pattern of modulating time domain discrete data sample block frequently of peak-to-average power ratio of falling of the present invention is modulated the time domain discrete data sample block choosing method with the empty frequency of peak-to-average power ratio that falls with minimum peak-to-average power ratio, but the very high big peak power signal probability of the maximum peak power that not only can make full use 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 being adopted 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 each wireless multi-media broadcast signal transmitter in the single frequency network and embed training sequence discrete sample block, the training sequence of each wireless multi-media broadcast signal transmitter in the single frequency network, the operational indicator sequence has pseudo-random characteristics, the training sequence of each wireless multi-media broadcast signal transmitter in the single frequency network, the operational indicator sequence has orthogonality each other, it is by falling the empty time domain discrete data sample block of frequently modulating of peak-to-average power ratio that the empty time domain discrete data sample block of frequently modulating of peak-to-average power ratio falls in the time domain embedding training sequence of each wireless multi-media broadcast signal transmitter in the single frequency network, time domain embeds training sequence discrete sample block and directly superposes and form, and these have guaranteed that each wireless multi-media broadcast signal receiver in the single frequency network 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 the empty time domain discrete data sample block of frequently modulating of peak-to-average power ratio, can reduce the interference effect between the adjacent signals frame to form signal frame.Each different operational indicator sequence of each wireless multi-media broadcast signal transmitter in the single frequency network is comprising and unique each system parameters and business model information of expressing each wireless multi-media broadcast signal transmitter in the single frequency network, digital television single-frequency network 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.Framing modulator approach 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 plurality of advantages such as High Data Rate may command multi-service digital television single-frequency network radio multimedium broadcast transmitted.

Description of drawings

Fig. 1 is the embodiment schematic diagram according to the single frequency network transmitter of single frequency network wireless multimedia broadcast signal framing modulator approach of the present invention.

Fig. 2 is the embodiment schematic diagram according to the single frequency network transmitter signal framing modulation of single frequency network wireless multimedia broadcast signal framing modulator approach of the present invention.

Embodiment

Below in conjunction with accompanying drawing specific embodiments of the invention are described in detail.

The embodiment of the single frequency network transmitter of the single frequency network wireless multimedia broadcast signal framing modulator approach that proposes according to the present invention as shown in Figure 1, follows these steps to carry out:

1) the network data management device of single frequency network will be imported data bit flow and form the FFT data block on frequency domain, and FFT represents the fast discrete Fourier conversion, and the length of FFT data block is K;

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

3) each wireless multi-media broadcast signal transmitter in the single frequency network adopts IFFT that sky is modulated the FFT data block frequently and is transformed to the empty time domain discrete data sample block D that frequently modulates _Total, IFFT represents the fast discrete Fourier inverse transformation;

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

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

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

6) each wireless multi-media broadcast signal transmitter in the single frequency network is with the real part sequence of training sequence as sequence of plural training, the operational indicator sequence is provided with the imaginary part sequence of the set operational indicator sequence in unit as sequence of plural training, on time domain, constitute the discrete sample block of sequence of plural training, training sequence, the operational indicator sequence, the length of the discrete sample block of sequence of plural training all is X, the operational indicator sequence is comprising and unique each system parameters and business model information of expressing each wireless multi-media broadcast signal transmitter in the single frequency network, and X gets 512,1024, in 2048 one;

7) each wireless multi-media broadcast signal transmitter in the single frequency network will repeat 4 times continuously and form time domain embedding training sequence discrete sample block on time domain in the discrete sample block of the sequence of plural training that constitutes on the time domain, time domain embeds the length of training sequence discrete sample block and falls the empty length numerically equal of modulating time domain discrete data sample block frequently of peak-to-average power ratio, i.e. K=4 * X; 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) each wireless multi-media broadcast signal transmitter in the single frequency network will fall the empty time domain discrete data sample block, time domain of frequently modulating of peak-to-average power ratio and embed training sequence discrete sample block and directly superpose and form time domain and embed training sequence and fall that peak-to-average power ratio is empty frequently modulates time domain discrete data sample block, as frame;

9) each wireless multi-media broadcast signal transmitter in the single frequency network at interval is that frame head inserts time domain and embeds training sequence and fall peak-to-average power ratio empty frequently to modulate time domain discrete data sample block be frame with Cyclic Prefix as protection, 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) each wireless multi-media broadcast signal transmitter in the single frequency network adopts square root raised cosine filter that the signal pulse of signal frame is shaped;

11) each wireless multi-media broadcast signal transmitter in the single frequency network with the baseband signal up-conversion to carrier wave.

Embodiment according to the single frequency network transmitter signal framing of single frequency network wireless multimedia broadcast signal framing modulator approach of the present invention is modulated, as shown in Figure 2, specifically implement as follows:

The network data management device of single frequency network will be imported data bit flow and form the FFT data block on frequency domain; Adopting code check is that FFT data block that 1 space-frequency coding device will form on frequency domain is modulated to form on each wireless multi-media broadcast signal transmitter branches in the single frequency network and emptyly frequently modulates the FFT data block, and the time synchronized of adjusting each wireless multi-media broadcast signal transmitter branches is all modulated the FFT data block frequently to sky at one time and handled to guarantee all transmitters in the network; Through IFFT it is transformed to the empty time domain discrete data sample block of frequently modulating again, generates and choose the empty time domain discrete data sample block of frequently modulating of peak-to-average power ratio of falling that wherein has minimum peak-to-average power ratio by the peak-to-average power ratio adjustment unit and simultaneously the generate pattern information of the corresponding employing of institute is sent to the operational indicator sequence unit is set.

Empty frequency is modulated the FFT data block and is made up of subcarrier.Empty length of modulating the FFT data block frequently 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.

Each wireless multi-media broadcast signal transmitter in the single frequency network 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 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 each wireless multi-media broadcast signal transmitter in the single frequency network 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 each wireless multi-media broadcast signal transmitter in the single frequency network.

Each wireless multi-media broadcast signal transmitter in the single frequency network will fall the empty time domain discrete data sample block, time domain of frequently modulating of peak-to-average power ratio and embed training sequence discrete sample block and directly superpose and form time domain and embed training sequence and fall that peak-to-average power ratio is empty frequently modulates time domain discrete data sample block, as frame; Fall empty frequently modulation of peak-to-average power ratio at time domain embedding training sequence and insert Cyclic Prefix in the time domain discrete data sample block, form signal frame as the protection interval.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.

Each wireless multi-media broadcast signal transmitter in the single frequency network 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.

In conjunction with the accompanying drawings specific embodiments of the invention are had been described in detail 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 (7)

1. a single frequency network wireless multimedia broadcast signal framing modulator approach is characterized in that it comprises the following steps:

1) the network data management device of single frequency network will be imported data bit flow and form the FFT data block on frequency domain, and FFT represents the fast discrete Fourier conversion, and the length of FFT data block is K;

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

3) each wireless multi-media broadcast signal transmitter in the single frequency network adopts IFFT that sky is modulated the FFT data block frequently and is transformed to the empty time domain discrete data sample block D that frequently modulates _Total, IFFT represents the fast discrete Fourier inverse transformation;

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

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

And the empty time domain discrete data sample block of frequently modulating of peak-to-average power ratio will be fallen

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

6) each wireless multi-media broadcast signal transmitter in the single frequency network with training sequence as the real part sequence of sequence of plural training, the operational indicator sequence is provided with the imaginary part sequence of the set operational indicator sequence in unit as sequence of plural training, on time domain, constitute the discrete sample block of sequence of plural training, 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 each wireless multi-media broadcast signal transmitter in the single frequency network;

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

8) each wireless multi-media broadcast signal transmitter in the single frequency network will fall the empty time domain discrete data sample block, time domain of frequently modulating of peak-to-average power ratio and embed training sequence discrete sample block and directly superpose and form time domain and embed training sequence and fall that peak-to-average power ratio is empty frequently modulates time domain discrete data sample block, as frame;

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

10) each wireless multi-media broadcast signal transmitter in the single frequency network adopts square root raised cosine filter that the signal pulse of signal frame is shaped;

11) each wireless multi-media broadcast signal transmitter in the single frequency network with the baseband signal up-conversion to carrier wave.

2. by the single frequency network wireless multimedia broadcast signal framing modulator approach of claim 1, it is characterized in that: the length X of the discrete sample block of the training sequence of each wireless multi-media broadcast signal transmitter in the described single frequency network, operational indicator sequence, sequence of plural training is got in 512,1024,2048.

3. by the single frequency network wireless multimedia broadcast signal framing modulator approach of claim 2, it is characterized in that: described training sequence, operational indicator sequence are formed by a series of 1 or-1.

4. by the single frequency network wireless multimedia broadcast signal framing modulator approach of claim 2, it is characterized in that: described training sequence, operational indicator sequence have pseudo-random characteristics.

5. by the single frequency network wireless multimedia broadcast signal framing modulator approach of claim 2, it is characterized in that: described training sequence, operational indicator sequence have orthogonality each other.

6. by the single frequency network wireless multimedia broadcast signal framing modulator approach of claim 1, it is characterized in that: described empty frequency is modulated the FFT data block and is made up of subcarrier; When X got 512, sub-carrier number got 2048, and the frequency interval of subcarrier is got 4KHz; When X got 1024, sub-carrier number got 4096, and the frequency interval of subcarrier is got 2KHz; When X got 2048, sub-carrier number got 8192, and the frequency interval of subcarrier is got 1KHz.

7. by the single frequency network wireless multimedia broadcast signal framing modulator approach of claim 1, it is characterized in that: the length C value of described Cyclic Prefix is relevant with the X value; When X got 512, C got 1/4 of K size; When X got 1024, C got 1/8 of K size; When X got 2048, C got 1/16 of K size.

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