CN102065047A - Transmitting method and device of double-transmitting-antenna OFDM (Orthogonal Frequency Division Multiplexing) signals - Google Patents

Abstract

The invention relates to a transmitting method and device of double-transmitting-antenna OFDM (Orthogonal Frequency Division Multiplexing) signals. The transmitting method comprises the following steps of: 1, adding a pilot frequency signal to a data block subjected to space-time coding, and respectively generating frequency-domain OFDM symbols on two transmitting links; 2, carrying out inverse Fourier transform on the frequency-domain OFDM symbols to generate time-domain OFDM symbols; and 3, respectively transmitting the two paths of transmitting signals at the same time through two transmitting antenna after the two paths of transmitting signals are synchronously controlled. The transmitting device comprises a pilot frequency adding module, an OFDM symbol generation module and a synchronous control module. By adopting the method and the device, a double-transmitting-antenna OFDM system which is compatible with a single-transmitting-antenna OFDM system can be realized; and meanwhile, the transmission efficiency of the double-transmitting-antenna OFDM system cannot be reduced, and the complexity of channel estimation cannot be remarkably increased.

Description

The launching technique of a kind of pair of transmitting antenna ofdm signal and emitter thereof

Technical field

The present invention relates to digital information transmission technical field, especially relate to a kind of launching technique and emitter thereof of digital multimedia broadcasting system of the two transmitting antennas based on ofdm signal.

Background technology

The principal element that influences signal quality in the wireless transmission environment is the decline of channel, and the decline of adopting the multi-antenna diversity method can resist wireless channel effectively, for system provides reliable message transmission.Transmit diversity has become the hot technology of discussing in recent years, and obtained good application in some mobile communication as the anti fading main method.In addition, transmit diversity techniques also is easy to Space Time Coding, OFDM (Orthogonal Frequency Division Multiplexing), disturbs technology such as inhibition and smart antenna to combine, farthest improve the reliability of physical layer information transmission, therefore have very high theory and be worth and great realistic significance.

OFDM is an orthogonal frequency division multiplexi, is a kind of of multi-carrier modulation.Mainly be that channel is divided into some orthogonal sub-channels, convert high-speed data signal to parallel low speed sub data flow, be modulated on each subchannel and transmit.Orthogonal signalling can separately can reduce the phase mutual interference ICI between the subchannel like this by adopt correlation technique at receiving terminal.In broadcast system based on OFDM, adopt pilot tone to carry out channel estimating usually, its basic process is: insert pilot tone in the transmitting terminal appropriate position, receiving terminal utilizes pilot tone to recover the channel information of pilot frequency locations, obtains the channel information of all periods then.In ofdm system, pilot signal is a time-frequency two-dimensional.In order to improve the precision of estimation, can insert continuous pilot and discrete guide-frequency signal.The coherence time and the coherence bandwidth of channel depended at interval between the pilot signal, and on time domain, the interval of pilot tone should be less than coherence time; On frequency domain, the interval of pilot tone should be less than coherence bandwidth.

The notion of transmit diversity is extended by reception diversity technology.It is the effect for attenuated signal decline, uses a plurality of independently antennas or associated antenna array, and the duplicate that transmits is offered receiving terminal with the form of spatial redundancy.The diversity emission utilizes the antenna of diverse location in different base station or the same base station to transmit and arrives the irrelevance of travelling carriage, Rake diversity reception function by travelling carriage, receive the signal diversity merging again of sending respectively, thereby improve systematic function by different antennae or different base station.

In two system of transmit antennas, the received signal of each reception antenna is that a plurality of transmitting antenna transmits through the stack behind the channel, and this carries out channel estimating with regard to the pilot tone of giving the reception data of utilizing each reception antenna and has brought inconvenience.How rationally and dexterously to dispose pilot tone, and system transmissions efficient is not descended, just become a key issue of two transmitting antennas-ofdm system design at transmitting terminal.

Summary of the invention

For this reason, the launching technique and the emitter thereof that the purpose of this invention is to provide a kind of two transmitting antennas based on ofdm signal.

For achieving the above object, according to the invention provides technical scheme as described below.

The launching technique of a kind of pair of transmitting antenna ofdm signal, this method comprises the steps:

Step 1, the data block that generates behind the process Space Time Coding are added pilot signal, generate the frequency-domain OFDM symbol respectively then on two transmitting chains;

Step 2, the frequency-domain OFDM symbol is carried out inverse Fourier transform, generate the time domain OFDM symbol;

Step 3, two-way transmission signals send by two transmitting antennas respectively at synchronization through after the Synchronization Control.

The emitter of a kind of pair of transmitting antenna ofdm signal, this device comprise,

Pilot tone is added module, after being used for pilot signal is inserted into the data block of Space Time Coding module output, is loaded into and generates the frequency-domain OFDM symbol on effective subcarrier;

OFDM symbol generation module is used for the frequency-domain OFDM symbol that has added pilot signal is carried out inverse Fourier transform, obtains the time domain OFDM symbol;

Synchronization control module, it is synchronous to be used to control the two-way radiofrequency signal;

The present invention is by adopting said method and device thereof, rationally and dexterously disposed discrete guide-frequency signal, the efficiency of transmission that has kept two transmitting antenna ofdm systems, and this system can with single transmit antenna ofdm system compatibility, and do not increase the complexity of channel estimating.

Description of drawings

Fig. 1 is the flow chart according to the launching technique of of the present invention pair of transmitting antenna ofdm signal;

Fig. 2 is the signal distribution plots according to the scattered pilot configuration mode one of transmitting antenna 1 of the present invention;

Fig. 3 is the signal distribution plots according to the scattered pilot configuration mode one of transmitting antenna 2 of the present invention;

Fig. 4 is the signal distribution plots according to the scattered pilot configuration mode two of the bright transmitting antenna 1 of we;

Fig. 5 is the signal distribution plots according to the scattered pilot configuration mode two of transmitting antenna 2 of the present invention;

Fig. 6 is the emitter structure chart according to of the present invention pair of transmitting antenna ofdm signal;

Fig. 7 is the data frame structure figure according to of the present invention pair of transmitting antenna ofdm signal.

Embodiment

Describe in further detail below with reference to accompanying drawings according to the launching technique of of the present invention pair of transmitting antenna ofdm signal and the specific embodiment of emitter thereof.

Fig. 1 shows the flow chart according to the launching technique of of the present invention pair of transmitting antenna ofdm signal.As shown in FIG., this method comprises the steps:

Step 1, the data block that generates behind the process Space Time Coding are added pilot signal, generate the frequency-domain OFDM symbol respectively then on two transmitting chains;

Step 2, the frequency-domain OFDM symbol is carried out inverse Fourier transform, generate the time domain OFDM symbol;

Step 3, two-way transmission signals send by two transmitting antennas respectively at synchronization through after the Synchronization Control.

Wherein, step 1 comprises the steps:

A. carry out Space Time Coding

Data after information source data stream process chnnel coding and the data map are divided into data block corresponding to effective sub-carrier number of each OFDM symbol, to each data block { s ₀, s ₁... s _K-1The load number of subcarriers of each OFDM symbol (K for) carry out Space Time Coding and generate two data block { s behind the coding ₀, s ₁... s _K-1And s ' ₀, s ' ₁... s ' _K-1, wherein

$s_i^{\′}=\left\{\begin{array}{cc}{-s}_{i+1}^{*},& i=2n\\ s_{i-1}^{*},& i=2n+1\end{array}\right.,$ $\frac{K-1}{2}\≥n\≥0.$

B. pilot tone is added

Data block { s behind the Space Time Coding ₀, s ₁... s _K-1And s ' ₀, s ' ₁... s ' _K-1In two transmitting chains of correspondence, be positioned over the load sub-carrier positions place of frequency-domain OFDM symbol respectively.

If select scattered pilot configuration mode one for use in system, for the individual OFDM symbol of n (n 〉=0), the configuration of the scattered pilot of transmitting antenna 1 is as follows:

If n is an even number, its scattered pilot data are 1+j0; If n be odd number then pilot data also for 1+j0.

The scattered pilot configuration of transmitting antenna 2 is as follows:

If n is an even number, its scattered pilot data are 1+j0; If n be odd number then pilot data be-1+j0.

Wherein, transmitting antenna 1 is identical with the position that the scattered pilot of transmitting antenna 2 is placed, and effective subcarrier number m value rule of scattered pilot correspondence is as follows in the individual OFDM symbol of the n of every frame (n 〉=0):

if?mod(n，2)＝＝0

$m=\left\{\begin{array}{cc}8p+1,& p=\mathrm{0,1},...,M\\ 8p+3,& p=M+1,M+2,...,2M+1\end{array}\right.$

if?mod(n，2)＝＝1。

$m=\left\{\begin{array}{cc}8p+5,& p=\mathrm{0,1},...,M\\ 8p+7,& p=M+1,M+2,...,2M+1\end{array}\right.$

Wherein parameter M sees Table 2 corresponding to the value of above ofdm system.

If select scattered pilot configuration mode two for use in system, for the individual OFDM symbol of n (n 〉=0), the configuration of the scattered pilot of transmitting antenna 1 is as follows:

If mod (n, 4)=0 or mod (n, 4)=1, then its scattered pilot data are 1+j0; If mod (n, 4)=2 or mod (n, 4)=3, then the scattered pilot data are 1+j0.

The scattered pilot configuration of transmitting antenna 2 is as follows:

If mod (n, 4)=0 or mod (n, 4)=1, then its scattered pilot data are-1+j0; If mod (n, 4)=2 or mod (n, 4)=3, then the scattered pilot data are 1+j0.

Wherein, transmitting antenna 1 is identical with the position that the scattered pilot of transmitting antenna 2 is placed, and effective subcarrier number m value rule of scattered pilot correspondence is as follows in the individual OFDM symbol of the n of every frame (n 〉=0):

if?mod(n，4)＝＝0

$m=\left\{\begin{array}{cc}8p+1,& p=\mathrm{0,1},...,M\\ 8p+3,& p=M+1,M+2,...,2M+1\end{array}\right.$

if?mod(n，4)＝＝1

$m=\left\{\begin{array}{cc}8p+5,& p=\mathrm{0,1},...,M\\ 8p+7,& p=M+1,M+2,...,2M+1\end{array}\right.$

if?mod(n，4)＝＝2

$m=\left\{\begin{array}{cc}8p+3,& p=\mathrm{0,1},...,M\\ 8p+5,& p=M+1,M+2,...,2M+1\end{array}\right..$

if?mod(n，4)＝＝3

$m=\left\{\begin{array}{cc}8p+7,& p=\mathrm{0,1},...,M\\ 8p+1,& p=M+2,M+3,...,2M+2\end{array}\right.$

Wherein parameter M sees Table 2 corresponding to the value of above ofdm system.

Continuous pilot and scattered pilot add finish after, on two transmitting chains, generate frequency-domain OFDM symbol { S respectively _iAnd S ' _i.

In addition, the operation principle of step 2 is as follows:

At first, in two transmitting chains the frequency-domain OFDM symbol that has added pilot frequency information is carried out inverse Fourier transform, promptly IFFT obtains the time domain OFDM symbol.

$t_n=\mathrm{IFFT}\left(S_i\right)=\underset{i=0}{\overset{N-1}{\mathrm{\Σ}}}{S}_i{e}^{j2\mathrm{\πin}/N},$ 0≤n≤N-1

$t_n^{\′}=\mathrm{IFFT}\left(S_i^{\′}\right)=\underset{i=0}{\overset{N-1}{\mathrm{\Σ}}}{S}_i^{\′}{e}^{j2\mathrm{\πin}/N},$ 0≤n≤N-1

Wherein N is a FFT length.

Then, the data frame structure that provides according to Fig. 7 passes through the multiple connection generation Frame of time domain OFDM symbol.

In addition, in step 3, two-way radiofrequency signal t (t) and t ' (t) are controlled by synchronization control module and send by two transmitting antennas respectively at synchronization.

If the information that the scattered pilot of a single transmit antenna ofdm system carries is sequence { X _i; 0≤i＜C (C is the scattered pilot number); then its transmitting antenna 1 still sends signal by the scattered pilot collocation method of single transmit antenna ofdm system in of the present invention pair of transmitting antenna ofdm system, and transmitting antenna 2 transmit with the signal of transmitting antenna 1 in identical scattered pilot position send and { X _iQuadrature sequence X ' _i, make X ' _i=X _iE ^{Ji π}, 0≤i＜C.

The sample rate of several ofdm systems of table 1, system bandwidth, scattered pilot quantity and FFT length

Table 1 has designed 13 kinds of ofdm systems.These systems all have frame structure as shown in Figure 7, and each Frame all comprises sender unit identification sequence, two synchronous heads and OFDM time-domain signal following closely.

In above 13 kinds of ofdm systems scattered pilot dispose two kinds of patterns, respectively as Fig. 2 and shown in Figure 4, they represent the sub-carrier configuration figure of the configuration mode of the scattered pilot in the transmitting antenna 1 respectively.In addition, Fig. 3 and Fig. 5 then represent the sub-carrier configuration figure of the configuration mode of the scattered pilot in the transmitting antenna 2 respectively.

Parameter M under two kinds of patterns of table 2 in the corresponding subcarrier number value of the scattered pilot rule

The emitter of a kind of pair of transmitting antenna ofdm signal, this structure drawing of device comprise as shown in Figure 6,

Pilot tone is added module, is used for pilot signal is inserted into through the data block behind the Space Time Coding, generates the frequency-domain OFDM symbol;

OFDM symbol generation module is used for above-mentioned frequency-domain OFDM symbol is carried out inverse Fourier transform, obtains the time domain OFDM symbol;

Synchronization control module, it is synchronous to be used to control the two-way radiofrequency signal.

Wherein, adding module by pilot tone is inserted into continuous pilot signal and discrete guide-frequency signal through in the data block behind the Space Time Coding and be loaded into effective sub-carrier positions place of frequency-domain OFDM symbol, obtain the time domain OFDM symbol through OFDM symbol generation module, this time domain OFDM symbol is handled the back through framing and is generated transmission frame, is sent by two transmitting antennas respectively at synchronization by synchronization control module control two paths of signals then.

In addition, pilot tone is added module and is comprised,

The Space Time Coding device is used for the information source data stream data after through chnnel coding and data map are carried out Space Time Coding corresponding to the load subcarrier data of each OFDM symbol;

The pilot tone adder is used for pilot signal is inserted into after the data block of described Space Time Coding device output, is loaded into and generates two-way frequency-domain OFDM symbol on effective subcarrier.

Wherein, the course of work of Space Time Coding device is as follows:

Data after information source data stream process chnnel coding and the data map are divided into data block corresponding to effective sub-carrier number of each OFDM symbol, to each data block { s ₀, s ₁... s _K-1The load number of subcarriers of each OFDM symbol (K for) carry out Space Time Coding and generate two data block { s behind the coding ₀, s ₁... s _K-1And s ' ₀, s ' ₁... s ' _K-1, wherein

$s_i^{\′}=\left\{\begin{array}{cc}{-s}_{i+1}^{*},& i=2n\\ s_{i-1}^{*},& i=2n+1\end{array}\right.,$ $\frac{K-1}{2}\≥n\≥0.$

In addition, in the pilot tone adder, to the data block { s behind the Space Time Coding ₀, s ₁... s _K-1And s ' ₀, s ' ₁... s ' _K-1In two transmitting chains of correspondence, be positioned over the valid data sub-carrier positions place of frequency-domain OFDM symbol respectively.

If select scattered pilot configuration mode one for use in system, for the individual OFDM symbol of n (n 〉=0), the configuration of the scattered pilot of transmitting antenna 1 is as follows:

If n is an even number, its scattered pilot data are 1+j0; If n be odd number then pilot data also for 1+j0.

The scattered pilot configuration of transmitting antenna 2 is as follows:

If n is an even number, its scattered pilot data are 1+j0; If n be odd number then pilot data be-1+j0.

Wherein, transmitting antenna 1 is identical with the position that the scattered pilot of transmitting antenna 2 is placed, and effective subcarrier number m value rule of scattered pilot correspondence is as follows in the individual OFDM symbol of the n of every frame (n 〉=0):

if?mod(n，2)＝＝0

$m=\left\{\begin{array}{cc}8p+1,& p=\mathrm{0,1},...,M\\ 8p+3,& p=M+1,M+2,...,2M+1\end{array}\right.$

if?mod(n，2)＝＝1。

$m=\left\{\begin{array}{cc}8p+5,& p=\mathrm{0,1},...,M\\ 8p+7,& p=M+1,M+2,...,2M+1\end{array}\right.$

Wherein parameter M sees Table 2 corresponding to the value of above ofdm system.

If select scattered pilot configuration mode two for use in system, for the individual OFDM symbol of n (n 〉=0), the configuration of the scattered pilot of transmitting antenna 1 is as follows:

If mod (n, 4)=0 or mod (n, 4)=1, then its scattered pilot data are 1+j0; If mod (n, 4)=2 or mod (n, 4)=3, then the scattered pilot data are 1+j0.

The scattered pilot configuration of transmitting antenna 2 is as follows:

If mod (n, 4)=0 or mod (n, 4)=1, then its scattered pilot data are-1+j0; If mod (n, 4)=2 or mod (n, 4)=3, then the scattered pilot data are 1+j0.

Wherein, transmitting antenna 1 is identical with the position that the scattered pilot of transmitting antenna 2 is placed, and effective subcarrier number m value rule of scattered pilot correspondence is as follows in the individual OFDM symbol of the n of every frame (n 〉=0):

if?mod(n，4)＝＝0

$m=\left\{\begin{array}{cc}8p+1,& p=\mathrm{0,1},...,M\\ 8p+3,& p=M+1,M+2,...,2M+1\end{array}\right.$

if?mod(n，4)＝＝1

$m=\left\{\begin{array}{cc}8p+5,& p=\mathrm{0,1},...,M\\ 8p+7,& p=M+1,M+2,...,2M+1\end{array}\right.$

if?mod(n，4)＝＝2

$m=\left\{\begin{array}{cc}8p+3,& p=\mathrm{0,1},...,M\\ 8p+5,& p=M+1,M+2,...,2M+1\end{array}\right..$

if?mod(n，4)＝＝3

$m=\left\{\begin{array}{cc}8p+7,& p=\mathrm{0,1},...,M\\ 8p+1,& p=M+2,M+3,...,2M+2\end{array}\right.$

Wherein parameter M sees Table 2 corresponding to the value of above ofdm system.

Continuous pilot and scattered pilot add finish after, on two transmitting chains, generate frequency-domain OFDM symbol { S respectively _iAnd S ' _i.

In addition, the operation principle of OFDM symbol generation module is as follows: at first, in two transmitting chains, the frequency-domain OFDM symbol that has added pilot frequency information is carried out inverse Fourier transform (IFFT), obtain the time domain OFDM symbol,

$t_n=\mathrm{IFFT}\left(S_i\right)=\underset{i=0}{\overset{N-1}{\mathrm{\Σ}}}{S}_i{e}^{j2\mathrm{\πin}/N},$ 0≤n≤N-1；

$t_n^{\′}=\mathrm{IFFT}\left(S_i^{\′}\right)=\underset{i=0}{\overset{N-1}{\mathrm{\Σ}}}{S}_i^{\′}{e}^{j2\mathrm{\πin}/N},$ 0≤n≤N-1；

Wherein N is a FFT length.

Then, the data frame structure that provides according to Fig. 7 passes through the multiple connection generation Frame of time domain OFDM symbol.

In addition, two-way radiofrequency signal t (t) and t ' (t) are controlled by synchronization control module and send by two transmitting antennas respectively at synchronization.

The method according to this invention and device thereof make the present invention have following characteristics:

A). can with single transmit antenna ofdm system compatibility;

B). can not reduce the efficiency of transmission of system;

C). the complexity of not obvious increase channel estimating;

D). with the compatibility of CMMB system scattered pilot configuration.

One of ordinary skill in the art will appreciate that and realize that all or part of step that the foregoing description method is carried is to instruct relevant hardware to finish by program, described program can be stored in a kind of computer-readable recording medium, this program comprises one of step or its combination of method embodiment when carrying out.

In addition, each functional unit in each embodiment of the present invention can be integrated in the processing module, also can be that the independent physics in each unit exists, and also can be integrated in the module two or more unit.Above-mentioned integrated module both can adopt the form of hardware to realize, also can adopt the form of software function module to realize.If described integrated module realizes with the form of software function module and during as independently production marketing or use, also can be stored in the computer read/write memory medium.

The above-mentioned storage medium of mentioning can be a read-only memory, disk or CD etc.

The above only is a preferred implementation of the present invention; should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the principle of the invention; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.

Claims (15)

1. the launching technique of two transmitting antenna ofdm signals is characterized in that this method comprises the steps:

Step 1, the data block that generates behind the process Space Time Coding are added pilot signal, generate the frequency-domain OFDM symbol respectively then on two transmitting chains;

Step 2, the frequency-domain OFDM symbol is carried out inverse Fourier transform, generate the time domain OFDM symbol;

Step 3, two-way transmission signals send by two transmitting antennas respectively at synchronization through after the Synchronization Control.

2. the launching technique of as claimed in claim 1 pair of transmitting antenna ofdm signal is characterized in that, the two-way time domain OFDM symbol that obtains in the described step 2 is respectively t _nAnd t ' _n, wherein,

$t_n=\mathrm{IFFT}\left(S_i\right)=\underset{i=0}{\overset{N-1}{\mathrm{\Σ}}}{S}_i{e}^{j2\mathrm{\πin}/N},$ 0≤n≤N-1；

$t_n^{\′}=\mathrm{IFFT}\left(S_i^{\′}\right)=\underset{i=0}{\overset{N-1}{\mathrm{\Σ}}}{S}_i^{\′}{e}^{j2\mathrm{\πin}/N},$ 0≤n≤N-1；

N is the length of Fourier transform.

3. the launching technique of as claimed in claim 1 pair of transmitting antenna ofdm signal is characterized in that described step 1 comprises the steps:

A. carry out Space Time Coding, be used for the information source data stream data after through chnnel coding and data map are carried out Space Time Coding corresponding to the load subcarrier data of each OFDM symbol;

B. pilot tone is added, and is used for pilot signal is inserted into behind the two paths of data piece of described Space Time Coding module output, is loaded into and generates two-way frequency-domain OFDM symbol on effective subcarrier.

4. the launching technique of as claimed in claim 3 pair of transmitting antenna ofdm signal is characterized in that, the two paths of data piece that generates among the described step a is respectively { s ₀, s ₁... s _K-1And s ' ₀, s ' ₁... s _K-1, wherein

K is the load number of subcarriers of each OFDM symbol.

5. the launching technique of as claimed in claim 3 pair of transmitting antenna ofdm signal is characterized in that, among the described step b, the information that the scattered pilot of transmitting antenna 1 carries is sequence { X _i, 0≤i＜C, and identical scattered pilot place sends and { X in the transmitting of transmitting antenna 2 _iQuadrature sequence X ' _i, make X ' _i=X _ie ^{Ji π}, wherein C is the number of scattered pilot.

6. the launching technique of as claimed in claim 3 pair of transmitting antenna ofdm signal is characterized in that, among the described step b for n OFDM symbol, n 〉=0 wherein, the configuration mode of scattered pilot is divided into:

The scattered pilot of pattern one, transmitting antenna 1 is configured to, if n is an even number, then its scattered pilot data are 1+j0, if n is an odd number, then its scattered pilot data also are 1+j0; The scattered pilot of transmitting antenna 2 is configured to, if n is an even number, then its scattered pilot data are 1+j0; If n is an odd number, then its scattered pilot data are-1+j0.

The scattered pilot of pattern two, transmitting antenna 1 is configured to, if mod (n, 4)=0 or mod (n, 4)=1, then its scattered pilot data are 1+j0, if mod (n, 4)=2 or mod (n, 4)=3, then the scattered pilot data are 1+j0; The scattered pilot of transmitting antenna 2 is configured to, if mod (n, 4)=0 or mod (n, 4)=1, then its scattered pilot data are-1+j0; If mod (n, 4)=2 or mod (n, 4)=3, then the scattered pilot data are 1+j0.

7. the launching technique of as claimed in claim 6 pair of transmitting antenna ofdm signal is characterized in that, effective subcarrier number m value of configuration mode one correspondence of described scattered pilot is:

if?mod(n，2)＝＝0

$m=\left\{\begin{array}{cc}8p+1,& p=\mathrm{0,1},...,M\\ 8p+3,& p=M+1,M+2,...,2M+1\end{array}\right.$

if?mod(n，2)＝＝1。

$m=\left\{\begin{array}{cc}8p+5,& p=\mathrm{0,1},...,M\\ 8p+7,& p=M+1,M+2,...,2M+1\end{array}\right.$

8. the launching technique of as claimed in claim 6 pair of transmitting antenna ofdm signal is characterized in that, effective subcarrier number m value of configuration mode two correspondences of described scattered pilot is:

if?mod(n，4)＝＝0

$m=\left\{\begin{array}{cc}8p+1,& p=\mathrm{0,1},...,M\\ 8p+3,& p=M+1,M+2,...,2M+1\end{array}\right.$

if?mod(n，4)＝＝1

$m=\left\{\begin{array}{cc}8p+5,& p=\mathrm{0,1},...,M\\ 8p+7,& p=M+1,M+2,...,2M+1\end{array}\right.$

if?mod(n，4)＝＝2

$m=\left\{\begin{array}{cc}8p+3,& p=\mathrm{0,1},...,M\\ 8p+5,& p=M+1,M+2,...,2M+1\end{array}\right..$

if?mod(n，4)＝＝3

$m=\left\{\begin{array}{cc}8p+7,& p=\mathrm{0,1},...,M\\ 8p+1,& p=M+2,M+3,...,2M+2\end{array}\right.$

9. the emitter of two transmitting antenna ofdm signals is characterized in that, this device comprises,

Pilot tone is added module, is used for pilot signal is inserted into through data block behind the Space Time Coding, generates the frequency-domain OFDM symbol;

OFDM symbol generation module is used for the frequency-domain OFDM symbol that has added pilot signal is carried out inverse Fourier transform, obtains the time domain OFDM symbol;

Synchronization control module, it is synchronous to be used to control the two-way radiofrequency signal.

Wherein, adding module by pilot tone is inserted into continuous pilot signal and discrete guide-frequency signal through in the data block after the Space Time Coding module and be loaded into effective sub-carrier positions place of frequency-domain OFDM symbol, obtain the time domain OFDM symbol through OFDM symbol generation module, this time domain OFDM symbol is handled the back through framing and is generated transmission frame, is sent by two transmitting antennas respectively at synchronization by synchronization control module control two paths of signals then.

10. the emitter of as claimed in claim 9 pair of transmitting antenna ofdm signal, it is characterized in that, adopt inverse Fourier transform that the two-way frequency-domain OFDM symbol that has added pilot frequency information is become two-way time domain OFDM symbol in the described OFDM symbol generation module, its transformation for mula is:

$t_n=\mathrm{IFFT}\left(S_i\right)=\underset{i=0}{\overset{N-1}{\mathrm{\Σ}}}{S}_i{e}^{j2\mathrm{\πin}/N},$ 0≤n≤N-1；

$t_n^{\′}=\mathrm{IFFT}\left(S_i^{\′}\right)=\underset{i=0}{\overset{N-1}{\mathrm{\Σ}}}{S}_i^{\′}{e}^{j2\mathrm{\πin}/N},$ 0≤n≤N-1；

Wherein, N is the length of Fourier transform.

11. the emitter of as claimed in claim 9 pair of transmitting antenna ofdm signal is characterized in that, described pilot tone is added module and is comprised,

The Space Time Coding device is used for the information source data stream data after through chnnel coding and data map are carried out Space Time Coding corresponding to the load subcarrier data of each OFDM symbol;

The pilot tone adder is used for pilot signal is inserted into behind the two paths of data piece of described Space Time Coding device output, is loaded into and generates the frequency-domain OFDM symbol on effective subcarrier.

12. the emitter of as claimed in claim 11 pair of transmitting antenna ofdm signal is characterized in that, the two paths of data piece that described Space Time Coding device generates is respectively { s ₀, s ₁... s _K-1And s ' ₀, s ' ₁... s ' _K-1, wherein

K is the load number of subcarriers of each OFDM symbol.

13. the emitter of as claimed in claim 11 pair of transmitting antenna ofdm signal is characterized in that, the configuration mode of scattered pilot is divided in the described pilot tone adder:

The scattered pilot of pattern one, transmitting antenna 1 is configured to, if n is an even number, then its scattered pilot data are 1+j0, if n is an odd number, then its scattered pilot data also are 1+j0; The scattered pilot of transmitting antenna 2 is configured to, if n is an even number, then its scattered pilot data are 1+j0; If n is an odd number, then its scattered pilot data are-1+j0.

The scattered pilot of pattern two, transmitting antenna 1 is configured to, if mod (n, 4)=0 or mod (n, 4)=1, then its scattered pilot data are 1+j0, if mod (n, 4)=2 or mod (n, 4)=3, then the scattered pilot data are 1+j0; The scattered pilot of transmitting antenna 2 is configured to, if mod (n, 4)=0 or mod (n, 4)=1, then its scattered pilot data are-1+j0; If mod (n, 4)=2 or mod (n, 4)=3, then the scattered pilot data are 1+j0.

14. the emitter of as claimed in claim 13 pair of transmitting antenna ofdm signal is characterized in that, the configuration mode one of described scattered pilot, and corresponding n OFDM symbol, wherein effective subcarrier number m value of scattered pilot correspondence is in n 〉=0:

if?mod(n，2)＝＝0

$m=\left\{\begin{array}{cc}8p+1,& p=\mathrm{0,1},...,M\\ 8p+3,& p=M+1,M+2,...,2M+1\end{array}\right.$

if?mod(n，2)＝＝1。

$m=\left\{\begin{array}{cc}8p+5,& p=\mathrm{0,1},...,M\\ 8p+7,& p=M+1,M+2,...,2M+1\end{array}\right.$

15. the emitter of as claimed in claim 13 pair of transmitting antenna ofdm signal is characterized in that, the pattern two of described configuration scattered pilot, and corresponding n OFDM symbol, wherein effective subcarrier number m value of scattered pilot correspondence is in n 〉=0:

if?mod(n，4)＝＝0

$m=\left\{\begin{array}{cc}8p+1,& p=\mathrm{0,1},...,M\\ 8p+3,& p=M+1,M+2,...,2M+1\end{array}\right.$

if?mod(n，4)＝＝1

$m=\left\{\begin{array}{cc}8p+5,& p=\mathrm{0,1},...,M\\ 8p+7,& p=M+1,M+2,...,2M+1\end{array}\right.$

if?mod(n，4)＝＝2。

$m=\left\{\begin{array}{cc}8p+3,& p=\mathrm{0,1},...,M\\ 8p+5,& p=M+1,M+2,...,2M+1\end{array}\right..$

if?mod(n，4)＝＝3

$m=\left\{\begin{array}{cc}8p+7,& p=\mathrm{0,1},...,M\\ 8p+1,& p=M+2,M+3,...,2M+2\end{array}\right.$

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