CN101162961A - Method and system of preventing co-channel interference - Google Patents

Abstract

A method for avoiding cochannel interference, at sending end, comprises steps: N data symbols are transported at the corresponding M*N stripes carrier position of each cell. The N data symbols are processed with repetition and equidifferent phase change. The complete signals are mapped into a subchannel made up of M*N stripes carriers by each cell. The mapped signals are processed and then are transmitted. By the method of the invention, the separation of cochannel signals can be realized, the cochannel interference is eliminated basically, especially, the mutual interference among the cell signals is eliminated, thus the good foundation is created for the application of high order modulation, the technology of simplified power control, etc., the technology of simplified frequency reuse, etc. In addition, the whole performance of the system is promoted.

Description

The method and system of avoiding cochannel to disturb

Technical field

The present invention relates to field of information transmission, particularly insert in (OFDMA) system, the method and system of avoiding cochannel to disturb at OFDM (hereinafter to be referred as OFDM)/OFDM.

Background technology

Be convenient narration, the sub-district of hereinafter only describing of the present invention; In fact, similar with cell conditions, the present invention is applicable to the situation of sector and cell set too.

OFDM is a kind of sound communication technology of carrying out the effective information transmission in channel.This technology utilizes a plurality of subcarriers (sub-carrier frequency) parallel, the transmission low-rate data to realize the communication of high data rate.Its technical essential is that the Channel Transmission bandwidth is divided into the plurality of sub frequency band, uses the subcarrier transmitting data information of mutually orthogonal on each sub-band concurrently, utilizes the orthogonality of its each subcarrier at receiving terminal, isolates the data message of parallel transmission.

The OFDM technology successfully has been applied in many communication systems, and for example, WLAN standard IEEE802.11 and wireless metropolitan area network standard IEEE802.16 have just adopted the OFDM technology.Along with the continual renovation of communication service, various new business demands constantly occur, and the OFDMA technology is also generally used gradually, for example, and wireless metropolitan area network standard IEEE802.16e.The OFDMA technology is based on the OFDM technology, can form different subchannels by divide different Resource Block in running time-frequency resource, carries out different traffic assignments, thereby realizes greater flexibility.

Become universal way along with setting up many cell structures with the OFDM/OFDMA technology, under many cell conditions, the performance at cell edge place draws attention day by day like this.Present situation to the many sub-districts of OFDM/OFDMA, mainly be that user in the sub-district is divided, cell boundary users is distinguished, these certain customers give stronger coding intensity, power level, or face the not frequency band of usefulness of sub-district, perhaps adopt disturbance that cochannel is disturbed schemes such as becoming noise.

Cochannel disturbs and is caused by channeling usually, promptly can produce the phase mutual interference usually with the quilt number of delivering a letter frequently simultaneously.Neighbor cell is not transmitting simultaneously or in the channel of different frequencies, obviously can reduce cochannel and disturb, but greatly reduce spectrum efficiency simultaneously yet; And at the same time with keeping pouring under the defeated situation, the prior art scheme all do not avoid the interference of neighbor cell all the time, and the power of this interference is usually much larger than thermal noise overcoming aspect the cochannel interference, cause user job in lower signal noise ratio level, performance is not good.Thereby the prior art scheme haves much room for improvement.

Summary of the invention

The purpose of this invention is to provide a kind of method and system of avoiding cochannel to disturb.

According to an aspect of of the present present invention, a kind of method of avoiding cochannel to disturb at transmitting terminal, comprises step:

A), transmit N data symbol in the M*N of each sub-district correspondence bar sub-carrier positions;

B) N data symbol carried out repetition and carry out the equal difference phase change;

C) each sub-district signal map that structure is finished is in a subchannel that is made of M*N bar subcarrier;

D) signal to mapping sends after handling.

According to another aspect of the present invention, a kind of method of avoiding cochannel to disturb at receiving terminal, comprises step:

The superposed signal of a plurality of sub-districts of receiving is carried out mathematic(al) manipulation obtain new data;

The signal that from new data, separates each sub-district;

The sequence that extracts is carried out the inverse transformation of M*N point mathematics conversion, and carry out changing with the transmitting terminal opposite phases.

According to another aspect of the present invention, a kind of system that avoids cochannel to disturb at transmitting terminal, comprising:

Information source module, each sub-district produces the information that will send;

The data pre-processing module is used for the information that information source module is come is carried out source encoding, chnnel coding, modulation etc., can also comprise the phase place rotation of aforementioned information symbol;

The information replicated blocks, the information that the data pre-processing module is come repeatedly repeats;

Add the equal difference phase module, the information that the information replicated blocks come is added the equal difference phase place according to the position ordinal number;

The data map module, with after multiplexing from the information mapping of adding the equal difference phase module to subchannel;

Frequently/time modular converter, as the IDFT module, will carry out frequency/time conversion from the information of data map module, and send after adding CP.

According to another aspect of the present invention, a kind of system that avoids cochannel to disturb at receiving terminal, comprising:

Receiver module, finish the user to time of system and frequency synchronously;

Removing module is used to delete the CP of the signal that collects;

The multicarrier demodulation module, as the DFT module, in the time of will carrying out from the signal of deletion module/the frequency conversion;

Extraction module extracts needed sub-channel data from the frequency domain data that the multicarrier demodulation module is changed out;

The F computing module carries out the F calculation process to the data from extraction module;

Separation module is finished the separation of multi-cell signals from the data from the F computing module;

Contrary F computing module, the data to separation module are carried out the inverse operation of F computing, obtain the frequency domain transmission data of original transmitted;

Processing module is carried out processing such as channel compensation, demodulation sign indicating number to the frequency domain data that obtains, obtain the most initial information data.

By method of the present invention, can realize the separation of co-channel signal, substantially eliminated the cochannel interference, especially, substantially eliminated the phase mutual interference between the cell signal, thereby be technology such as the application of high order modulation, the power control of simplification, the channeling technology of simplifying etc. has been created good basis, has promoted the overall performance of system.

Description of drawings

Fig. 1 is that the data format under the same allocation of carriers of a plurality of sub-districts forms schematic diagram;

Fig. 2 is that each cell signal extracts schematic diagram;

Fig. 3 is four cell structure schematic diagrames;

Fig. 4 is that repeating data forms schematic diagram under four cell structures, wherein, and M=4, N=16;

Fig. 5 is the sending end structure schematic diagram;

Fig. 6 is the receiving terminal structural representation;

Fig. 7 is the functional schematic of repetition;

Fig. 8 is the functional schematic that adds the equal difference phase place;

Fig. 9 is the transmitting terminal process chart;

Figure 10 is the receiving terminal process chart;

Figure 11 is a quick-reading flow sheets example of data pre-treatment;

Figure 12 is a quick-reading flow sheets example of Data Post;

Figure 13 realizes that data repeat and add an equivalent substitution scheme of equal difference phase place;

Figure 14 realizes that data repeat and add an equivalent substitution scheme of equal difference phase place;

Figure 15 is the big subcarrier allocation schematic diagrames of several channel degrees of correlation.

Embodiment

The invention provides a kind of method and transmission and receiving system of avoiding cochannel to disturb.New transmission method and system by the present invention proposes make many sub-districts superposed signal effectively to separate, and transmitting terminal need be handled subscriber signal under the coordination mode of many sub-districts, comprise that the characteristic sequence that proposes with this paper is associated.Receiving terminal can effectively separate many sub-districts superposed signal, under some ideal conditions by corresponding receiving algorithm, even can avoid cochannel to disturb, and obtain diversity gain, cell reuse and networking mode flexibly, the power control techniques of simplifying etc., thus the overall performance of system promoted.

The present invention can be used for the up link (claim not only reverse link) and/or the down link (but also claiming forward link) of message transmission.Describing for convenient, is that example describes with down link (being sent by the base station) only below.

The present invention is finished by transmitting terminal and the acting in conjunction of receiving terminal two parts.

In the following description, described principle is equally applicable to sub-channel (being made of several or a subcarrier) except being used for sub-channel, or notion such as sub carrier group.Easy for describing, only explain below with subchannel.

Being without loss of generality, is example with the OFDM/OFDMA multi-cell system below, describes the information processing method that the present invention proposes.

Be convenient narration, the down link with a sub-district is an example below, the method for sending and receiving of descriptor.

Corresponding to the to be sent burst A of some sub-districts in a channel or sub-channel, at first can carry out an initial phase rotation, obtain a burst B who adds the initial phase rotation.Adding the initial phase rotation is an option.Next, burst B (perhaps A) repeatedly duplicated produce new burst D, to the signal D phase change of this sub-district appointment in addition, phase change comprises that positive phase changes and the minus phase variation, sends then.Have more detailed description below the detailed process that sends.At receiving terminal, each the sub-district superposed signal that receives by F computing of the present invention, can effectively be separated each cell signal.Through operations such as corresponding inverse operation and further decodings, just can solve original sequence again.

At first, suppose that the number of sub carrier wave that the user who is concerned about prepares reception is M*N, the running time-frequency resource that this M*N bar subcarrier occupies is called a subchannel.Suppose total Q sub-district in the residing cell set of user, Q is not more than M.

Transmitting terminal constitutes and method:

On the M*N of each sub-district correspondence bar subcarrier, reality only transmits N data symbol, and this N data symbol is to have finished source encoding, the data after the chnnel coding, processes such as modulation.This N data symbol note made burst A (i), i=1,2 ..., N.Burst A (i) is carried out the initial phase rotation, obtain burst $B\left(i\right)=A\left(i\right)*e^{{\mathrm{j\θ}}_i},$ I=1,2 ..., N, and be without loss of generality θ _i∈ [0,2 π].

B (i) is duplicated M time, and the M value is not limited to 2 integer power.For example, with reference to figure 3, in order to be used for being made of three sub-districts the situation of a cell set, M can get 3,4,5 or bigger; In order to be used for being made of seven cell the situation of a cell set, M can get 7,14 or 8 etc.Duplicate the back and form a new sequence D that contains N*M symbol (i), i=1,2 ..., M*N.Wherein, i is carried out modulo operation, when mould is N, D (i%N)=D (i) is arranged.

Sequence D (i) is carried out equal difference phase change φ (i) according to sequence number i, i=1,2 ..., M*N.2 π * q/M (also can adopt reverse phase rotation-2 π * q/M) for example, wherein q is corresponding with this sub-district one and is not less than zero integer, the q difference of neighbor cell less than M.Be without loss of generality, here q might as well get an integer from 0 to Q-1, as shown in Figure 1.The key feature of this signal is: in this M*N φ (i), and φ (i)-φ (i-N)=τ, τ is a definite value, i=1,2 ..., M*N.Be without loss of generality, τ can be 2 π * q/M.

Signal D (i) the * e that each self-structuring is finished in each sub-district ^{φ (i)}, i=1,2 ..., M*N is mapped in the subchannel that is made of M*N bar subcarrier.Then, carry out frequency/time conversion of IDFT/IFFT, add CP, and send according to certain power Pq.

Receiving terminal constitutes and method:

Suppose that the user has finished Time and Frequency Synchronization, at this moment, the signal that the user receives is the superposed signal of a plurality of sub-districts, remove CP after, carry out DFT/FFT the time/frequency change.Then, the M*N point data on user's subchannel that can propose to be distributed.At this moment, this M*N point data on this subchannel is a superposed signal, contains the co-channel signal of a plurality of sub-districts.

For ease of describing basic principle, below the influence of temporary transient slightly denoising and channel fading.Simultaneously, we will use a kind of computing, be defined as the F computing:

The F computing is meant the mathematic(al) manipulation with following operating characteristic, X (n) _ F (D)

1) if the D sequence is a sequence that has repeated M time, sequence length is L=M*N, M, and N is positive integer, and D (i%N)=D (i), i=1,2 ..., M*N, % represent modulo operation here, and D (0)=D (N%N),

So, the X sequence will be data to occur at interval with M, and other position is ' 0 '.

2) if multiply by the equal difference phase change to sequence D, the cyclic shift characteristic will appear in the X sequence so.Be expressed as follows:

F (D (i) e ^{J φ (i)})=X (n-f (τ)), φ (i)-φ (i-N)=τ wherein, τ is a definite value.When τ was definite value, f (τ) also was a definite value.

Its inverse operation should have and 1) 2) symmetrical character.Mathematic(al) manipulation with F operating characteristic has a lot, DFT transfer pair for example, Z-transformation equity.Might as well describe with DFT below.The user carries out M*N point F computing to the M*N data that receive and obtains X.X is extracted with interval M, and all the other positions mend 0.The extraction scheme as shown in Figure 2.The sequence that extracts is carried out the inverse transformation of M*N point F, and correspondence carries out the phase place despining, for example :-2 π * q/M; If that transmitting terminal adopts is reverse phase rotation-2 π * q/M, just carries out forward phase so here and compensate 2 π * q/M.Can obtain N*M data symbol D of each sub-district of original transmission.Perhaps X is extracted with interval M, carry out the inverse transformation of N point F then and, directly can obtain N data symbol B of original transmission divided by M.

Need to prove in addition, this declarative description be the situation of a multi-cell system, in fact situations such as single sub-district multi-user are suitable for too, be added on the same subchannel so long as meet many groups signal that the present invention launches rule, the present invention is just effectively.

Fig. 5 is the sending end structure schematic diagram.

Module 501 is information source module, and each sub-district produces the information that will send here.

Module 502 is data pre-processing modules, finishes source encoding, chnnel coding, and functions such as modulation can also comprise the phase place rotation of aforementioned information symbol.

Module 503 is information replicated blocks, and here the information that the front is come repeatedly repeats.

Module 504 is to add the equal difference phase module, adds the equal difference phase place according to the position ordinal number here.

Module 503 and 504, especially module 504 are core characteristics of transmitting terminal in this method.

Module 505 is data map modules, will come from the data that are re-used of different data streams or information source etc., carries out the mapping of data to subchannel.

Module 506 is multi-carrier modulation modules, as the IDFT module.

Module 507 is added recycling-guard prefix CP.

Module is a transmitter module.

Fig. 6 is the receiving terminal structural representation.

Module 601 is finished the Time and Frequency Synchronization function.

Module 602 is finished deletion CP function.

Module 603 is multicarrier demodulation modules, as the DFT module, counts and counts for the OFDM symbol, finishes the conversion of OFDM time-domain symbol to frequency domain data.

Module 604 is finished sub-channel data and is extracted.

The data that 605 pairs of subchannels of module extract are carried out F conversion (for example DFT conversion), count to be sub-channel data length.

Module 606 is taken out the data that belong to different districts.Sometimes also finish the demultiplexing function.

Module 607 is carried out the inverse transformation of module 605, because separated each cell data in module 606, can obtain the mask data of each sub-district here.

Module 605,606,607th, the core content of this algorithm receiver side.

Module 608 is finished channel compensation, and reprocessings such as demodulation sign indicating number obtain data through processing and are sent to 609.Rotate if added the phase place of information symbol at transmitting terminal, also should carry out the phase place despining information symbol.

So module 609 will obtain original data.

Fig. 7 is the functional schematic of repetition, and here length is that the sequence X of N expands to the sequence Y that length is N * M, and Y is arranged in order by M X and constitutes.

Fig. 8 is the functional schematic that adds the equal difference phase place, by the phase place rotation here, is definite value at a distance of the difference for the rotatable phase between the data of N (N=L/M).

Fig. 9 is the transmitting terminal process chart.

Fig. 9 has described the flow chart of data processing of transmitting terminal, and step 901 has produced the initial data that will send, and sends into data pre-treatment step 902, comprises source encoding, chnnel coding, functions such as modulation, the phase place rotation of all right additional information symbol.Treated data are carried out data and are repeated work (step 903); add specific equal difference phase place at step 904 place then the data that generate; the data that will come from different data streams or information source etc. according to the multiplexing needs of reality; be mapped on the selected subchannel subcarrier by step 905 through multiplexing back; finish the conversion of frequency/time by step 906 then; the time domain sequences that produces is added recycling-guard prefix CP in step 907, and the data after interpolation finishes enter step 908 and send.

Figure 10 is the receiving terminal process chart.

Step 1001 expression receiving terminal has been finished time and Frequency Synchronization, and has gathered signal; In step 1002, the signal that collects is deleted CP, when then these data being carried out in step 1003/the frequency conversion.Step 1004 extracts needed sub-channel data from the frequency domain data of changing out.The step 1005 pair data that extract are carried out F computing (or contrary F computing) and are handled, can in step 1006, finish the separation of multiple sectors at same channel signal through the data of F calculation process, sometimes also can finish the demultiplexing process, the separation signal that is proposed is done the inverse operation (or F computing) of F computing in step 1007, can obtain original frequency domain transmission data.In step 1008, resulting frequency domain data passes through channel compensation, demodulation, and functions such as decoding just can obtain the most initial information data.In addition, if added the phase place rotation of information symbol, also should carry out the phase place despining to information symbol at transmitting terminal.

Figure 11 is a quick-reading flow sheets example of data pre-treatment, and actual conditions are not limited thereto.

Figure 12 is a quick-reading flow sheets example of Data Post, and actual conditions are not limited thereto.

Figure 13 realizes that data repeat and add an equivalent substitution scheme of equal difference phase place, and effect is equivalent to module 503 and module 504.Data repeat M earlier all over (module 1301), then by a F computing (module 1302) (as the DFT computing), the operation result that obtains will data occur with interval M, the inverse operation (module 1304) of F computing is done again to this result specific cyclic shift (module 1303) in this sub-district in addition in each sub-district then.

Figure 14 realizes that data repeat and add an equivalent substitution scheme of equal difference phase place, and effect is equivalent to module 503 and module 504.Data are carried out once contrary F computing or F computing (module 1401) earlier, the N bit data that obtains expands to the M*N position, method is that M-1 ' 0 ' (module 1402) all inserted in each data back, each sub-district remakes F computing or contrary F computing (module 1404) to this result specific cyclic shift (module 1403) in this sub-district in addition then.

Figure 15 is the big subcarrier allocation schematic diagrames of several channel degrees of correlation, duplicates 4 times.Under the non-flat forms channel condition, the signal that duplicates should be tried one's best close on time and frequency, and effect just can be better.

Also need to prove, the data that structure has this repeat property and adds the equal difference phase place also have other equivalent methods, for example shown in Figure 13, data repeat M earlier all over (module 1301), then by a M*N point DFT computing (module 1302), the operation result that obtains will data appear in M to occur at interval, and M*N point IDFT variation (module 1304) is done again to this result specific cyclic shift (module 1303) in this sub-district in addition in each sub-district then.

For example shown in Figure 14, data are carried out a N point DFT computing (module 1401) earlier, the N bit data that obtains then expands to the M*N position, method is that M-1 0 (module 1402) all inserted in each data back, each sub-district is M*N point IDFT again and is changed (module 1404) this result specific cyclic shift (module 1403) in this sub-district in addition then.

Need to prove that also the sequence number that the present invention mentioned all is the logic sequence number of the data in a subchannel, that is to say that it can not be the sequence number of physical sub-carrier.And the sequence number of it and physical sub-carrier can have multiple mapping relations, in the process of mapping, should note following principle:

The signal that duplicates should be arranged on the big subcarrier of the degree of correlation as far as possible, as shown in figure 15, but be not limited to situation shown in Figure 15, and guarantee as far as possible the signal that duplicates the sub-carrier channels of process smooth or similar, even like this in time/frequency-selective channel, that channel can be caused influences the symbol itself that equivalence is seted out and sent, and receiving terminal can think that this equivalence sends signal and carried out repetition and equal difference phase change, therefore still the Signal Separation of each sub-district can be come at receiving terminal.

Theory is described as follows, for M*N and do not consider that the situation of noise, the signal that receiving terminal is received can be expressed as a plurality of co-channel signals stack sums of following signal form,

When the structure signal:

$X_m^{i\%N}=X_m^i$

Here % represents modulo operation.And when the decline on the residing physical sub-carrier of signal that repeats is similar, can be similar to and thinks: $H_m^{i\%N}=H_m^i$ Therefore,

$X_m^{i\%N}{H}_m^{i\%N}=X_m^i{H}_m^i$

So as can be seen, the equivalent signal from a plurality of co-channel signals of many sub-districts that receives has also satisfied repetitive structure and the deflection of equal difference phase place, and therefore by aforesaid transmission reception flow process, each co-channel signal can be separated.

On the other hand, in the foregoing description,, both can distribute to M sub-district to M kind equal difference phase change for the situation of N data symbol being duplicated M time; Can be in the cell structure of a cell set with the individual sub-district of S (S＞=1) also, (Q=＜M) plants even or inhomogeneous R (the individual sub-district of R=＜Q) of distributing to of equal difference phase change Q; Be in the cell structure of a cell set with the individual sub-district of S (S＞=1) perhaps, adopting the method be similar to the CDMA multiple access technology, (it is even or inhomogeneously distribute to R sub-district that Q=＜M) plants the equal difference phase change Q.That is to say that both the sub-district that can include was assigned with the situation more than one equal difference phase change; Also the sub-district that can include only is assigned with one, even is not assigned with the situation of equal difference phase change.

Especially, for single cell system (S=1), above-mentioned distribution also can be worked.

Embodiment

As shown in Figure 3, be example with one 4 cell conditions, cell number m is followed successively by 0,1,2,3, and supposing respectively has a user to belong to each sub-district respectively in the cell boarder area, and the subchannel method of salary distribution is identical, will form cochannel between the subscriber signal and disturb.4 sub-districts send 16 data through pre-treatment respectively simultaneously on 64 formed subchannels of subcarrier.64 data that each sub-district sends are that four times by 16 data are duplicated and formed, and satisfy

$X_m^{i\%16}=X_m^i,$ M=0 wherein, 1,2,3.

Here X _m ⁱThe i bit data that expression sub-district m launches in that subchannel.Then, carry out corresponding equal difference phase change.

Form data as shown in Figure 4.

By transmission and reception as shown in Figure 5 and Figure 6, extract the data on corresponding 64 subcarriers at module 604 places, notice that the data on each subcarrier this moment all are the superposed signals of the data of four sub-districts.64 subcarriers that obtain are done the DFT conversion, obtain sequence Z.Notice 4 times of repeat property when structure sends signal and the equal difference phase change of being added, can each cell signal of following separation from sequence Z.

From sequence Z, extract sequence

[Z(0)，0，0，0，Z(4)，0，0，0......Z(60)，0，0，0]；

[0，Z(1)，0，0，0，Z(5)，0，0......0，Z(61)，0，0]；

[0，0，Z(2)，0，0，0，Z(6)，0，......0，0，Z(62)，0]；

[0，0，0，Z(3)，0，0，0，Z(7)......0，0，0，Z(63)]；

Carry out the IDFT conversion respectively, obtain the sequence z of corresponding each sub-district _m ⁱThe line phase inverse transformation of going forward side by side

This sequence just can be thought original 64 data that send in each sub-district.

Perhaps right

[Z(0)Z(4)......Z(60)]；

[Z(1)Z(5)，......Z(61)]；

[Z(2)Z(6)，......Z(62)]；

[Z(3)Z(7)......，Z(63)]；

Directly carry out the IDFT conversion, and, directly obtain 16 bit data signals of original transmission divided by 4.

If further consider working method at time/frequency-selective channel, can be in the big sub carrier group of as shown in figure 15 correlation with the signal map of duplicating, the channel of same sub-district experience can be thought to be similar in this group.For example, according to channel situation, X _m ³,

Be arranged in the adjacent sub-carrier as shown in figure 15, if do not consider noise, corresponding equivalent received signals can be written as: X _m ³H _m ³,

As seen be equivalent to sub-district m emission equivalent data X _m ³H _m ³Situation.

Therefore receive flow process by aforesaid emission, each co-channel signal can be separated.

For the method for avoiding cochannel to disturb of the present invention, and each module of transmitting terminal and receiving terminal, situation difference according to concrete implementation system, may have increase and decrease or order adjustment commonly used, but principle of the present invention is still set up, and this variation does not influence the enforcement of the present invention in this concrete system.In addition, for those of ordinary skill in the art, after reading the present invention, as long as follow principle of the present invention and/or thinking, can be applied in certain specific system (comprise original system is designed again, added the new system behind the present invention and be optimized) by some distortion so that make.

Claims (26)

1. method of avoiding cochannel to disturb at transmitting terminal, comprises step:

A), transmit N data symbol in the M*N of each sub-district correspondence bar sub-carrier positions;

B) N data symbol carried out repetition and carry out the equal difference phase change;

C) each sub-district signal map that structure is finished is in a subchannel that is made of M*N bar subcarrier;

D) signal to mapping sends after handling.

2. method according to claim 1, it is characterized in that fail to handle and comprise that frequency/time changes IFFT or IDFT and add CP.

3. method according to claim 1 is characterized in that described step b) comprises:

N data symbol repeated M time successively, form the sequence of a new N*M symbol;

N*M symbol to new formation carries out the equal difference phase change.

4. method according to claim 1 is characterized in that described step b) comprises:

N data symbol repeated M time successively, and then by a F computing, operation result is the data that occur with interval M;

Each sub-district to operation result in addition the specific cyclic shift in this sub-district do the inverse operation of F computing again.

5. method according to claim 1 is characterized in that described step b) comprises:

N data symbol carried out a F inverse operation or F computing, and the N bit data that obtains expands to the M*N position;

Each sub-district to operation result in addition the specific cyclic shift in this sub-district do the inverse operation of F computing again.

6. method according to claim 1 is characterized in that described step b) comprises:

N data symbol repeated M time successively, obtain the data that occur with interval M by M*N point DFT computing;

Each sub-district to operation result in addition the specific cyclic shift in this sub-district be M*N point IDFT again and change.

7. method according to claim 1 is characterized in that described step b) comprises:

N data symbol carried out N point DFT computing, and the N bit data that obtains expands to the M*N position;

Each sub-district to operation result in addition the specific cyclic shift in this sub-district be M*N point IDFT again and change.

8. method according to claim 1 is characterized in that described N data symbol is to have finished source encoding, chnnel coding and modulated process data afterwards.

9. method according to claim 1 is characterized in that described phase change comprises that positive phase changes or minus phase changes.

10. method according to claim 9 is characterized in that described phase change φ (i) satisfies following formula:

φ(i)-φ(i-N)＝τ

Wherein, τ is a definite value, and i is the sequence number of N*M symbol.

11. method according to claim 10 is characterized in that described τ value satisfies following formula:

2π*q/M

Wherein, q is not less than zero integer less than M.

12. method according to claim 11 is characterized in that the cochannel q value that correspondence is different of different districts.

13. method according to claim 1 is characterized in that described cochannel can all be mapped in single sub-district.

14. method according to claim 1 is characterized in that described sub-district is a sub-district at least.

15. a method of avoiding cochannel to disturb at receiving terminal, comprises step:

When carrying out/frequency conversion after, in a sub-channel data that extracts, the superposed signal of a plurality of sub-districts of receiving is carried out mathematic(al) manipulation obtains new data;

The signal that from new data, separates each sub-district;

The sequence that extracts is carried out the inverse transformation of M*N point mathematics conversion, and carry out changing with the transmitting terminal opposite phases.

16. method according to claim 15 is characterized in that described mathematic(al) manipulation has following character, establishing X is the mathematic(al) manipulation result of D sequence,

1) if the D sequence is a sequence that has repeated M time, sequence length is L=M*N, M, and N is positive integer, (D (i%N)=D (i), % represents modulo operation here), and the X sequence will be data to occur at interval with M so, other position is ' 0 ';

2) if multiply by the equal difference phase change to sequence D, the cyclic shift characteristic will appear in the X sequence so,

F(D(i)e ^jφ(i))＝X(n-f(τ)).

φ (i)-φ (i-N)=τ wherein, τ is a definite value.When τ was definite value, f (τ) also was a definite value.

17. method according to claim 15 is characterized in that mathematic(al) manipulation is DFT or IDFT.

18. method according to claim 15 is characterized in that the data after the mathematic(al) manipulation are extracted with interval M and obtains the sequence that M group N is ordered, and is used to separate the co-channel signal of different districts.

19. method according to claim 18 is characterized in that the sequence that the M that obtains group N is ordered is carried out the inverse transformation of N point mathematics conversion and then obtained N data symbol of original transmission.

20. method according to claim 15 is characterized in that data after the mathematic(al) manipulation extract all the other position zero paddings with interval M and obtain the sequence that M group M*N is ordered, and is used to separate the co-channel signal of different districts.

21. a system that avoids cochannel to disturb at transmitting terminal, comprising:

Information source module, each sub-district produces the information that will send;

The data pre-processing module is used for the information that information source module is come is carried out source encoding, chnnel coding, modulation, also comprises the phase place rotation of information symbol;

The information replicated blocks, the information that the data pre-processing module is come repeatedly repeats;

Add equal difference phase change module, the information that the information replicated blocks come is added the equal difference phase place according to the position ordinal number;

The data map module, with multiplexing from the information mapping of having added the equal difference phase change to subchannel;

Frequently/time modular converter, will carry out frequency/time conversion from the information of data map module, and send after adding CP.

22. system according to claim 21 is characterized in that the equal difference phase change φ (i) that described interpolation equal difference phase change module is added satisfies following formula:

φ(i)-φ(i-N)＝τ，

Wherein, τ is a definite value, and i is the sequence number of N*M symbol.

23. system according to claim 22 is characterized in that described τ value satisfies following formula:

2π*q/M

Wherein, q is not less than zero integer less than M.

24. system according to claim 23 is characterized in that the cochannel q value that correspondence is different of different districts.

25. a system that avoids cochannel to disturb at receiving terminal, comprising:

Receiver module, finish the user to time of system and frequency synchronously;

Removing module is used to delete the CP of the signal that collects;

The multicarrier demodulation module, as the DFT module, in the time of will carrying out from the signal of deletion module/the frequency conversion;

Extraction module extracts needed sub-channel data from the frequency domain data that the multicarrier demodulation module is changed out;

The F computing module carries out the F calculation process to the data from extraction module;

Separation module is finished the separation of multi-cell signals from the data from the F computing module;

Contrary F computing module, the data to separation module are carried out the inverse operation of F computing, obtain the frequency domain transmission data of original transmitted.

Processing module is carried out processing such as channel compensation, demodulation sign indicating number to the frequency domain data that obtains, obtain the most initial information data.

26. system according to claim 25 is characterized in that described F computing module finishes DFT computing or IDFT computing, accordingly, described contrary F computing module is finished IDFT computing or DFT computing.

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