CN105577313A - High-order modulation iterative neighborhood interference suppression method and device - Google Patents

Abstract

The invention belongs to the technical field of wireless communications and particularly provides a high-order modulation iterative neighborhood interference suppression method and a device. According to the technical scheme of the invention, the device comprises two parts, namely an OFDM neighboring cell interference suppression transmitter and a neighboring cell interference suppression receiver. The signal of the transmitter is interleaved by an interleaver and then is subjected to signal modulation. After that, by means of an initial information estimator and a signal channel decoder of the receiver, the prior information of the received signal is updated, and the interference is reduced. The receiver is primarily directed to an OFDM downlink and is provided on the basis of the high-order modulation-based neighboring cell interference suppression. Based on the initial information estimation method, the iterative high-order modulation is realized. The receiver is better in detection performance in different signal channel conditions. Meanwhile, the interference prevention capabilities of cell edge users in a heavy-load system can be improved.

Description

A kind of high order modulation iteration cell interference suppression method and device

Technical field

The invention belongs to wireless communication technology field, the method and apparatus that the presence of intercell interference being specifically related to a kind of high order modulation signal based on OFDM-IDMA suppresses.

Background technology

OFDM (OFDM) technology due to the ability having the higher availability of frequency spectrum and antagonism multipath effect be the major technique of next generation wireless communication.In order to obtain the higher availability of frequency spectrum, frequency reuse based on the cell system of OFDM is generally 1, therefore, for the downlink transfer of user, unavoidably cause the adjacent cell in cellular system to disturb (inter-cellinterference, ICI), reduce transmission reliability, the particularly interference from multiple community that is subject to of Cell Edge User, the antijamming capability how improving edge cell is the problem of main research at present.

Current several disturbance restraining methods comprise interference cooperation, interference randomization and interference delete.Interference cooperation technology such as partial frequency multiplexing, inter-cell power control and Resource Allocation Formula etc. can obtain good performance when system is in comparatively light and medium load, but in the system of full load, performance has very strong decline.Interference randomization technology as scrambler and frequency hopping can effectively suppress unique user be disturbed, and macroscopically do not reducing the Noise and Interference in whole system.Intertexture division multiple access technology can separate and eliminate the interference of other users, in more heavy duty system, have good prospect of the application.

Point multiple access (Interleave-divisionmultipleaccess, the IDMA) technology that interweaves eliminates interference by distributing different interleavers to different users, has higher performance compared to other orthogonal multiple access techniques.By being applied in OFDM by IDMA technology, the advantage of two kinds of technology can be made full use of, improving transmission throughput and bit error rate performance under a multipath channel environment.In the technology of current IDMA, initial information estimates that (ElementarySignalEstimator, ESE) method can realize in the QPSK modulator approach that BPSK and real part and imaginary part independently map.

The present invention is mainly for OFDM-IDMA down link, a kind of receiver of the adjacent cell AF panel based on high-order OFDM-IDMA is proposed, described in application the present invention, initial information estimates (ElementarySignalEstimator, ESE) method, realizes the high order modulation of IDMA.Simulation result shows, this receiver can provide good detection perform under different channels condition.

Summary of the invention

The method and apparatus that the presence of intercell interference that the object of the invention is to propose a kind of high order modulation signal based on OFDM-IDMA suppresses.

1, based on the adjacent cell AF panel transmitter of OFDM-IDMA

Figure 2 shows that the transmitter architecture of the adjacent cell AF panel of OFDM-IDMA.

Kth community is d to the bit that user sends _k=[d _k[1] ..., d _k[N _b]] ^t, after turbo coding, coded sequence is c _k=[c _k[1] ..., c _k[N _c]] ^t, through spreading code u _k=[u _k[1] ..., u _k[N _u]] ^tobtain s afterwards _k=[s _k[1] ..., s _k[N _s]] ^t, through interleaver pi _kobtain frequency domain signal X _k=[X _k[1] ..., X _k[N _x]], every Q in X _kbit combination is mapped to constellation symbol, obtains modulation sequence m _k=[m _k[1] ..., m _k[N _m/ Q _k]], mapping relations are:

$m_k\left(j\right)=map(\[X_k^1(j),...,X_k^{Qk}\left(j\right)\])---\left(1\right)$

Wherein q=1 ..., Q _k, be the q bit of a jth symbol of a kth base-station transmission, such as: m _k(j)=map ([0010]), then b _i(m _k(j))=0, i=1,2,4; b ₃(m _k(j))=1.

Time-domain symbol x is obtained through IFFT _k=[x _k[1] ..., x _k[N _x]], through channel h _kthe signal obtaining afterwards receiving is r.

2, based on the adjacent cell interference suppressing receiver of OFDM-IDMA

Figure 3 shows that the adjacent cell interference suppressing receiver structure of OFDM-IDMA.

Received signal strength r realizes obtaining r' after receiver end removes Cyclic Prefix (CP) and frame period (GI) makes FFT

$r^{\′}\left(j\right)=\underset{k=1}{\overset{K}{\Σ}}{h}_k^{{}^{\′}}{y}_k\left(j\right)+w^{\′}\left(j\right)---\left(2\right)$

Wherein, w'(j) be two dimension variances be σ ²white complex gaussian noise, omits j after not describing simplification, h' _kfor h _kequivalent channel after FFT.Initial estimation signal { e is obtained through ESE _eSE(x ₁(n)) }, after deinterleaving, obtain { e _eSE(c ₁(n)) }, obtain the estimation of signal after decoding decoded external information { e _dEC(c ₁(n)) } obtain { e through interweaving again _dEC(x ₁(n)) }, turn back to ESE and input as the external information of next iteration.

3, ESE algorithm in receiver

The idiographic flow of ESE is as follows:

(1) object of ESE calculates log-likelihood:

$e_{ESE}\left(x_k^{\left(q\right)}\right)=In\frac{P\left\{r\right|x_k^{\left(q\right)}=0\}}{P\left\{r\right|x_k^{\left(q\right)}=1\}}---\left(3\right)$

As the input of soft demodulation DEC.Signaling point probability on planisphere can be expressed as according to Bayes's equation, obtaining conditional probability is:

$P\left\{r^{\′}\right|x_k^{\left(q\right)}=a\}={\mathrm{\Σ}}_{s\∈S_{k,a}^{\left(q\right)}}P\{r|m_k=s\}\underset{l\≠q}{\Π}P\{x_k^{\left(l\right)}=b_l\left(s\right)\},a=0,1$

Wherein, $S_{k,a}^{\left(q\right)}=\{s\∈S_k:b_q\left(s\right)=a\},$ Can be obtained by (3) formula:

$\begin{array}{c}{e}_{ESE}\left(x_k^{\left(q\right)}\right)=In\frac{\underset{s\∈S_{k,0}^{\left(q\right)}}{\Σ}P\left\{r\right|m_k=s\}\underset{l\≠q}{\Π}P\{x_k^{\left(l\right)}=b_l\left(s\right)\}}{\underset{s\∈S_{k,1}^{\left(q\right)}}{\Σ}P\left\{r\right|m_k=s\}\underset{l\≠q}{\Π}P\{x_k^{\left(l\right)}=b_l\left(s\right)\}}\\ =In\frac{\underset{s\∈S_{k,0}^{\left(q\right)}}{\Σ}P\left\{r\right|m_k=s\}\exp \left\{\underset{l\≠q,b_{l\left(s\right)}=0}{\Σ}{L}_a\left(x_k^{\left(l\right)}\right)\right\}}{\underset{s\∈S_{k,1}^{\left(q\right)}}{\Σ}P\left\{r\right|m_k=s\}\exp \left\{\underset{l\≠q,b_{l\left(s\right)}=0}{\Σ}{L}_a\left(x_k^{\left(l\right)}\right)\right\}}\end{array}---\left(4\right)$

Wherein, $L_a\left(x_k^{\left(l\right)}\right)=In\frac{P\{x_k^{\left(l\right)}=0\}}{P\{x_k^{\left(l\right)}=1\}},$

Be referred to as priori value;

Can be obtained by formula (2):

Wherein, by k community be disturbed with noise and, obtained by center theorem for gaussian variable, therefore P{r'|m in formula (4) _k=s} is approximate meets Gaussian Profile.By probability P { r'|m _k=s} is expressed as vector form, wherein, and r'=(r ^rer ^im) ^t, s=(s ^res ^im) ^t,

Order for matrix average and variance matrix, then probability distribution is:

Wherein, $H_k^{\′}=\left(\begin{array}{cc}{\mathrm{\ρ}}_k{\mathrm{cos\θ}}_k& -{\mathrm{\ρ}}_k{\mathrm{sin\θ}}_k\\ {\mathrm{\ρ}}_k{\mathrm{sin\θ}}_k& {\mathrm{\ρ}}_k{\mathrm{cos\θ}}_k\end{array}\right),$ Represent channel gain complex matrix, by formula (5), average and variance can be expressed as:

${\mathrm{\μ}}_{r^{\′}}=\underset{l=1}{\overset{K}{\Σ}}{H}_l^{\′}{\mathrm{\μ}}_{m_l}---\left(7\right)$

${\mathrm{\Ξ}}_{r^{\′}}=\underset{l=1}{\overset{K}{\Σ}}{H}_l^{\′}{\mathrm{\Ξ}}_{m_l}{H}_l^{\′T}+{\mathrm{\σ}}^{2}I---\left(8\right)$

Wherein, with for matrix average and variance matrix upgrade with namely soft demodulation output valve returns the priori value of ESE as coded-bit by DEC:

$e_{DEC}\left(x_k^{\left(q\right)}\right(j\left)\right)=In\frac{P\left\{r\right|x_k^{\left(q\right)}\left(j\right)=0\}}{P\left\{r\right|x_k^{\left(q\right)}\left(j\right)=1\}}---\left(11\right)$

This priori value can be used to the probability upgrading signaling point on planisphere, and constellation point probability is:

$P\{m_k\left(j\right)=s\}=\underset{q=1}{\overset{Q_k}{\Π}}P\{x_k^{\left(q\right)}\left(j\right)=b_q\left(s\right)\},s\∈S_k---\left(12\right)$

Wherein, come from reuse formula (7)-(10), renewable with

According to foregoing, the method (namely based on the information transferring method of OFDM-IDMA) of the presence of intercell interference suppression of the high order modulation signal based on OFDM-IDMA provided by the invention, its step is summarized as follows: adopt the ofdm signal based on IDMA to send and receiving system model, transmitter signal carries out signal madulation again after interleaver interweaves, by ESE estimator in receiver and DEC decoder, upgrade the prior information of Received signal strength, reduce interference.The inventive method can promote the antijamming capability of Cell Edge User in more heavy duty system.

In said method, described OFDM-IDMA emission system model, for downlink data transmission, each base station uses independently interleaver, and user's interleaver demodulation of community residing for oneself obtains current base station signal.

In said method, described OFDM-IDMA receiving system model, receiver user first carries out the demodulation of OFDM, then carries out the soft demodulation of IDMA signal, is upgraded by the iteration of ESE estimator and DEC decoder, obtains Received signal strength.

In said method, described ESE estimator, according to the prior probability of receiving symbol, the prior information estimated value (by formula (4)) of each chip of deriving.

In said method, described DEC decoder, according to average and the variance of interference signal in Received signal strength renewal, return the priori value (by formula (11)) of coded-bit.

The device of the presence of intercell interference suppression of the high order modulation signal based on OFDM-IDMA provided by the invention, comprising: the above-mentioned adjacent cell AF panel transmitter based on OFDM-IDMA and the adjacent cell interference suppressing receiver two parts based on OFDM-IDMA.Transmitter architecture as shown in Figure 2, by turbo encoder, frequency multiplier, interleaver pi _k, modulator, inverse Fourier transform IFFT, cyclic prefix CP, protection interval GI, multipath channel CH etc. connect to form successively; Original bit flows through turbo encoder and carries out turbo coding, spread spectrum is carried out again by frequency multiplier, the random interleaving of signal is carried out subsequently by interleaver, then by modulator, this signal is modulated to high-order constellation signal (as 16QAM, 64QAM etc.) again, carry out OFDM encapsulation process again (to comprise and be IFFT to signal, add CP, encapsulation framing), by forming Received signal strength after multipath wireless channels.Described OFDM-IDMA receiving system model, for downlink data transmission, each base station uses independently interleaver, and user's interleaver demodulation of community residing for oneself obtains current base station signal; Receiver structure as shown in Figure 3, first Received signal strength is made demodulation process through demodulator to ofdm signal frame and (is comprised CP, FFT is done to signal, channel equalization), subsequently by ESE estimator, the estimated signal value obtained is by DEC decoder, output signal is estimated, and acquisition upgrades required prior information next time, upgrade Received signal strength ESE, iterative soft demodulation is carried out to signal.

The present invention is mainly for OFDM-IDMA down link, a kind of receiver of the adjacent cell AF panel based on high-order OFDM-IDMA is proposed, described in application the present invention, initial information estimates (ElementarySignalEstimator, ESE) method, realizes the high order modulation of IDMA.Simulation result shows, this receiver can provide good detection perform under different channels condition.

Advantage of the present invention:

(1) separately can eliminate the interference of different adjacent cells based on the receiver of OFDM-IDMA, in more heavy duty system, there is good performance;

(2) employ the method for reseptance of iterative soft demodulation based on the receiver of OFDM-IDMA, it receives the increase of complexity along with number of cells, increase linearly;

(3) the ESE algorithm described in, can be applicable in the OFDM-IDMA system of high order modulation, makes OFDM-IDMA can be applicable to the system of high data rate;

(4) receiver described in effectively reduces the antijamming capability of Cell Edge User.

Accompanying drawing explanation

Fig. 1 is 7 cell cellular system small area edge customers.

Fig. 2 is the transmitter architecture based on OFDM-IDMA.

Fig. 3 is the receiver structure based on OFDM-IDMA.

Fig. 4 is the bit error rate performance of OFDM-IDMA16QAM under awgn channel.

Fig. 5 is the bit error rate performance of OFDM-IDMA16QAM under Rayleigh channel.

Embodiment

To a kind of AF panel method of reseptance based on OFDM-IDMA that the present invention proposes, concrete steps are as follows:

1, as shown in Figure 1, be 7 cell cellular system small area edge customers, suppose that active user is among the A of community, its interference be subject to comes from the base station of other 6 communities, and suppose that all base station transmitting powers are identical, path loss and square distance are inversely proportional to.OFDM sub-carrier number is N=64, virtual subnet carrier number N _vc=16, circulating prefix-length N _cP=16, every frame has 3 OFDM symbol, and use 1/2 speed turbo coding, generator matrix is [111; 101], soft demodulation iterations is 5 times.

2, as shown in Figure 2, kth community is d to the bit that user sends _k=[d _k[1] ..., d _k[N _b]] ^t, after turbo coding, coded sequence is c _k=[c _k[1] ..., c _k[N _c]] ^t, through spreading code u _k=[u _k[1] ..., u _k[N _u]] ^tobtain s afterwards _k=[s _k[1] ..., s _k[N _s]] ^t, through interleaver pi _kobtain frequency domain signal X _k=[X _k[1] ..., X _k[N _x]], every Q in X _kbit combination is mapped to constellation symbol, obtains modulation sequence m _k=[m _k[1] ..., m _k[N _m/ Q _k]], mapping relations are:

$m_k\left(j\right)=map(\[X_k^1(j),...,X_k^{Q_k}(j)\])$

Wherein q=1 ..., Q _k, be the q bit of a jth symbol of a kth base-station transmission, such as m _k(j)=map ([0010]), then b _i(m _k(j))=0, i=1,2,4; b ₃(m _k(j))=1.Time-domain symbol x is obtained through IFFT _k=[x _k[1] ..., x _k[N _x]], through channel h _kthe signal obtaining afterwards receiving is r.

3, as shown in Figure 2, Received signal strength r realizes obtaining r' after receiver end removes Cyclic Prefix (CP) and frame period (GI) makes FFT:

$r^{\′}\left(j\right)=\underset{k=1}{\overset{K}{\Σ}}{h}_k^{\′}{y}_k\left(j\right)+w^{\′}\left(j\right)$

Wherein, w'(j) be two dimension variances be σ ²white complex gaussian noise, omits j after not describing simplification.Initial estimation signal { e is obtained through ESE _eSE(x ₁(n)) }, after deinterleaving, obtain { e _eSE(c ₁(n)) }, obtain the estimation of signal after decoding decoded external information { e _dEC(c ₁(n)) } obtain { e through interweaving again _dEC(x ₁(n)) } turn back to ESE and input as the external information of next iteration.

4, the ESE in calculation procedure 2, as the input of soft demodulation DEC.

Obtained by (3) formula:

$e_{ESE}\left(x_k^{\left(q\right)}\right)=In\frac{\underset{s\∈S_{k,0}^{\left(q\right)}}{\Σ}P\left\{r\right|m_k=s\left\}\exp \right\{\underset{l\≠q,b_{l\left(s\right)}=0}{\Σ}{L}_a\left(x_k^{\left(l\right)}\right)\}}{\underset{s\∈S_{k,1}^{\left(q\right)}}{\Σ}P\left\{r\right|m_k=s\left\}\exp \right\{\underset{l\≠q,b_{l\left(s\right)}=0}{\Σ}{L}_a\left(x_k^{\left(l\right)}\right)\}}$

Wherein, $L_a\left(x_k^{\left(l\right)}\right)=In\frac{P\{x_k^{\left(l\right)}=0\}}{P\{x_k^{\left(l\right)}=1\}}$ Be referred to as priori value.

Upgrade according to formula (7)-(10) with can obtain soft demodulation output valve DEC is:

$e_{DEC}\left(x_k^{\left(q\right)}\right(j\left)\right)=In\frac{P\left\{r\right|x_k^{\left(q\right)}\left(j\right)=0\}}{P\left\{r\right|x_k^{\left(q\right)}\left(j\right)=1\}}.$

5, the ESE expression formula of 16QAM

When adopting 16QAM high order modulation, adopt Gray code, under awgn channel, can H' be obtained _k=I, the 1st bit of then symbol utilizes formula (4) to be expressed as:

$\begin{array}{c}{e}_{ESE}\left({x_k}^{\left(1\right)}\right)=\ln \{\frac{P\left(r^{\′}\right|m_k=S_8)+P\left(r^{\′}\right|m_k=S_7)\exp \left\{L_{ESE}\left(x_k^{\left(4\right)}\right)\right\}+P\left(r^{\′}\right|m_k=S_6)\exp \left\{L_{ESE}\left(x_k^{\left(3\right)}\right)\right\}+\mathrm{...}}{P\left(r^{\′}\right|m_k=S_{16})+P\left(r^{\′}\right|m_k=S_{15})\exp \left\{L_{ESE}\left(x_k^{\left(4\right)}\right)\right\}+P\left(r^{\′}\right|m_k=S_{14})\exp \left\{L_{ESE}\left(x_k^{\left(3\right)}\right)\right\}+\mathrm{...}}\\ \frac{P\left(r^{\′}\right|m_k=S_4)\exp \left\{L_{ESE}\left(x_k^{\left(2\right)}\right)\right\}+P\left(r^{\′}\right|m_k=S_2)\left(\exp \right\{L_{ESE}\left(x_k^{\left(2\right)}\right)\}+\exp \{L_{ESE}\left(x_k^{\left(3\right)}\right)\left\}\right)\mathrm{...}}{P\left(r^{\′}\right|m_k=S_{12})\exp \left\{L_{ESE}\left(x_k^{\left(2\right)}\right)\right\}+P\left(r^{\′}\right|m_k=S_{10})\left(\exp \right\{L_{ESE}\left(x_k^{\left(2\right)}\right)\}+\exp \{L_{ESE}\left(x_k^{\left(3\right)}\right)\left\}\right)\mathrm{...}}\\ \frac{P\left(r^{\′}\right|m_k=S_3)\left(\exp \right\{L_{ESE}\left(x_k^{\left(2\right)}\right)\}+\exp \{L_{ESE}\left(x_k^{\left(4\right)}\right)\left\}\right)+\mathrm{...}}{P\left(r^{\′}\right|m_k=S_{11})\left(\exp \right\{L_{ESE}\left(x_k^{\left(2\right)}\right)\}+\exp \{L_{ESE}\left(x_k^{\left(4\right)}\right)\left\}\right)+\mathrm{...}}\\ \frac{P\left(r^{\′}\right|m_k=S_5)\left(\exp \right\{L_{ESE}\left(x_k^{\left(3\right)}\right)\}+\exp \{L_{ESE}\left(x_k^{\left(4\right)}\right)\left\}\right)+\mathrm{...}}{P\left(r^{\′}\right|m_k=S_{13})\left(\exp \right\{L_{ESE}\left(x_k^{\left(3\right)}\right)\}+\exp \{L_{ESE}\left(x_k^{\left(4\right)}\right)\left\}\right)+\mathrm{...}}\\ \frac{P\left(r^{\′}\right|m_k=S_1)\left(\exp \right\{L_{ESE}\left(x_k^{\left(2\right)}\right)+\exp \left\{L_{ESE}\left(x_k^{\left(2\right)}\right)\right\}+\exp \left\{L_{ESE}\left(x_k^{\left(4\right)}\right)\right\})}{P\left(r^{\′}\right|m_k=S_9)\left(\exp \right\{L_{ESE}\left(x_k^{\left(2\right)}\right)+\exp \left\{L_{ESE}\left(x_k^{\left(3\right)}\right)\right\}+\exp \left\{L_{ESE}\left(x_k^{\left(4\right)}\right)\right\})}\}\end{array}---\left(13\right)$

Similar with it, utilize formula (4) to extrapolate all the other expression formula.

6, Fig. 4, Fig. 5 are last simulation analysis result, wherein:

Fig. 4 simulates the BER performance based on the adjacent cell AF panel of OFDM-IDMA under awgn channel, and system uses the spread spectrum coefficient of 8,16, and from emulation, along with the increase of iterations, BER performance promotes gradually, and iterative receiver has constringency performance faster; When spread spectrum number is increased to 16 from 8, iteration brings the lifting of larger BER performance, and main cause is the growth along with spreading code, and the external information of feedback can react reception information more accurately, and therefore iteration brings performance boost faster.

The BER performance of the adjacent cell AF panel based on OFDM-IDMA under Rayleigh channel is simulated in Fig. 5, channel sample is Delay=[03568], channel tap power matrix is PowerdB=[0-8-17-21-25], the spread spectrum coefficient of emulation use 16,24.From emulation, OFDM-IDMA effectively can suppress the interference of adjacent cell, and convergence rate is very fast, ensures the reliability to serving cell channel, and simultaneously along with the increase of spread spectrum coefficient, iteration brings performance boost faster.

Claims (5)

1. based on the method that the presence of intercell interference of the high order modulation signal of OFDM-IDMA suppresses, it is characterized in that, adopt the ofdm signal based on IDMA to send and receiving system model; Original bit flows through turbo encoder and carries out turbo coding, spread spectrum is carried out again by frequency multiplier, the random interleaving of signal is carried out subsequently by interleaver, then by modulator, this signal is modulated to high-order constellation signal again, carry out OFDM encapsulation process again, comprise and signal is done to IFFT, adds CP, encapsulates framing; Received signal strength is formed after multipath wireless channels; The described ofdm signal receiving system model based on IDMA, for downlink data transmission, each base station uses independently interleaver, and user's interleaver demodulation of community residing for oneself obtains current base station signal.

2. as claimed in claim 1 based on OFDM-IDMA the method that suppresses of the presence of intercell interference of high order modulation signal, it is characterized in that, described based in the ofdm signal receiving system model of IDMA, first Received signal strength makes demodulation process to ofdm signal frame, comprises CP, does FFT, channel equalization to signal; Subsequently by ESE estimator in receiver, the estimated signal value obtained is by DEC decoder, and output signal is estimated, and acquisition upgrades required prior information next time, upgrades Received signal strength ESE, carries out soft demodulation to signal; Wherein:

Receiver user first carries out the demodulation of OFDM, then carries out the soft demodulation of IDMA signal, is upgraded by the iteration of ESE estimator and DEC decoder, obtains Received signal strength.

3. as claimed in claim 1 based on the method that the presence of intercell interference of the high order modulation signal of OFDM-IDMA suppresses, it is characterized in that, in described ESE estimator, according to the prior probability of receiving symbol, derive the prior information estimated value formula (4) of each chip, idiographic flow is as follows:

(1) log-likelihood is calculated:

（3）

As the input of soft demodulation DEC; Signaling point probability on planisphere is expressed as , according to Bayes's equation, obtaining conditional probability is:

Wherein , obtained by (3) formula:

（4）

Wherein, , be referred to as priori value.

4., as claimed in claim 2 based on the method that the presence of intercell interference of the high order modulation signal of OFDM-IDMA suppresses, it is characterized in that, in described DEC decoder, according to average and the variance of interference signal in Received signal strength renewal, return the priori value formula (11) of coded-bit, idiographic flow is as follows:

Obtained by formula (2):

（5）

Wherein, for community be disturbed and noise and, obtained by center theorem for gaussian variable, in formula (4) be similar to and meet Gaussian Profile; By probability be expressed as vector form, wherein , , , order for matrix average and variance matrix, then probability distribution is:

（6）

Wherein, represent channel gain complex matrix, by formula (5), average and variance be expressed as:

（7）

（8）

（9）

（10）

Wherein, with for matrix average and variance matrix;

Upgrade with , namely soft demodulation output valve returns the priori value of ESE as coded-bit by DEC:

（11）

This priori value is used for upgrading the probability of signaling point on planisphere, and constellation point probability is:

（12）

Wherein, come from , reuse formula (7)-(10), upgrade with .

5. based on method described in claim 1-4 OFDM-IDMA the device that suppresses of the presence of intercell interference of high order modulation signal, it is characterized in that comprising: the adjacent cell AF panel transmitter based on OFDM-IDMA and adjacent cell interference suppressing receiver two parts based on OFDM-IDMA.