CN101621490A - Method for modulation diversity joint codes of OFDM system - Google Patents

Abstract

The invention relates to a method for the modulation diversity of joint codes of an OFDM system. The method leads signal modulation diversity by modulating the rotation of a constellation picture and interlacing components, dispersedly distributes data prepared to be transmitted to different components by rotation modulation and component interlacement so that the data of the different components are respectively decayed on a channel to increase superiorities of signal space diversity, then selects an optical rotation angle to maximally enhance transmission property and also leads OFDM frequency diversity and time-frequency interlacement diversity, thereby more effectively enhancing the property of the system. The invention is improved from a previous invention patent application, i.e. a method for the signal diversity of the OFDM system (application number: 2008102264831) and expands an original diversity technique enhancing and improving the transmission property by two-dimensional rotation modulation to a multi-dimensional rotation modulation technique, thereby well utilizing the modulation diversity to be combined with time diversity and frequency domain diversity to enhance the property of the system.

Description

A kind of method that is used for the modulation diversity joint codes of ofdm system

Technical field

The present invention relates to a kind of method that is used for the modulation diversity joint codes of ofdm system, exactly, relate to a kind of method that in ofdm system, signal synthesis is adopted multidimensional rotation modulation, chnnel coding and diversity, so that can fully utilize the gain of time diversity, frequency diversity, modulation diversity and chnnel coding under the fading channel well, to reduce the frame error rate of system, belong to the diversity technique field in the data communication.

Background technology

After nineteen eighty-two Ungerboeck proposed Trellis-coded modulation TCM (Trellis Code Modulation) technology, coded modulation CM (Coded Modulation) technology was the popular research topic in the communications field all the time.The basic thought of TCM is that encoder and modulator are done as a wholely to take all factors into consideration and design, and makes the coded signal sequence that produces after encoder and the modulator cascade have maximum Euclidean distance.Present theory and practice has shown that all TCM can reach optimum performance in additive white Gaussian channel (AWGN Channel).Yet find when TCM is used for mobile fading channel: this moment, its performance became very poor.So how seeking best coded modulation scheme in fading channel just becomes hot research in recent years.

The advantage of TCM coding method is that this can play good effect in awgn channel with the Euclidean distance maximization of coded signal sequence.But for fading channel, the raising of performance is depended on to be increased the diversity number and increases long-pending distance, and this makes the TCM coding method, and nonexistence can advantage in the fading channel transmission.

Zehavi proposed Bit Interleave coded modulation algorithm BICM (Bit Interleave CodeModulation) at first in 1992, and this algorithm is compared with traditional TCM, and the performance under Rayleigh channel is significantly increased.People such as 1996 Nainas, G Caire have calculated the capacity of BICM scheme under the situation that ideal interweaves, the capacity that has proved the most of set of signals with Gray mapping is all almost equal with self capacity of set of signals.So understand in theory that BICM can obtain the coding gain identical with TCM, and be not only the encoding scheme of a kind of suboptimum of originally thinking.

In the BICM algorithm, the Bit Interleave technology that plays a decisive role has increased code modulated time diversity degree, yet, under Gaussian channel, its performance again because of minimum Eustachian distance reduce worsen.

Orthogonal frequency division multiplex OFDM (Orthogonal Frequency Division Multiplexing) is a kind of broad band multicarrier technology.It is to be converted to one group of low-speed parallel data flow transmitted by the data flow with high-speed transfer, the system that makes reduces greatly for the susceptibility degree of multidiameter fading channel frequency selectivity, thereby have good antinoise and anti-multipath interference capability, be applicable to and in frequency selective fading channels, carry out high speed data transfer.Therefore, people will expect naturally: if OFDM and BICM mode can be mutually combined, will further improve communication quality.

As everyone knows, in fading channel, the effect of " diversity " is extremely important.Under optimally diversified situation, error probability can be index decreased along with the increase of average signal-to-noise ratio.In the BICM algorithm, though the Bit Interleave technology has increased code modulated time diversity degree; But, because the reducing of minimum Eustachian distance, make the deterioration that becomes of the transmission performance of this technical scheme under Gaussian channel again.Therefore, how to solve this technical barrier, become the focus of scientific and technical personnel's concern in the industry.

Summary of the invention

In view of this, the purpose of this invention is to provide a kind of method that is used for the modulation diversity joint codes of ofdm system, the anglec of rotation and the component of this method by changing modulation constellation interweaves and introduces the signal modulation diversity, interweave by rotation modulation and component, to prepare the data diffusion profile of transmission to different components, make independent decline on each comfortable channels of data of different components, increase the advantage of signal space diversity; Select the optimum anglec of rotation again, obtain the maximum lift of transmission performance; Simultaneously, introduce OFDM frequency diversity and the time-frequency diversity that interweaves, thereby can more effectively improve systematic function.

In order to achieve the above object, the invention provides a kind of method that is used for the modulation diversity joint codes of ofdm system, it is characterized in that described method comprises following operating procedure:

(1) transmitting terminal carries out initialization process to sending data: each user's transmission data are encoded respectively and modulate according to the coding of setting and modulation system, according to the anglec of rotation of setting the I road in-phase component and the Q road quadrature component of the symbolic vector piece of all users after modulating are carried out multidimensional rotation modulation again, then the symbolic vector piece after the rotation modulation is stored;

(2) transmitting terminal is according to the symbolic vector piece distribution OFDM running time-frequency resource of the OFDM pattern of setting to all users in the memory, each user's symbolic vector piece is evenly distributed in each OFDM symbol successively, and the symbolic vector piece to each user in the OFDM symbol carries out Q road interleaving treatment again;

(3) transmitting terminal is according to default OFDM modulation length and inverse fast fourier transform IFFT computing length, respectively to not enough IFFT computing length in each OFDM symbol the position long zero padding, again each the OFDM symbol after the zero padding is comprised the IFFT computing and add the OFDM processing of cyclic prefix CP, send data then;

(4) after receiving terminal receives data, the OFDM that separates that CP and fast Fourier transform FFT computing are removed to this data block symbols by elder generation handles, carry out phase compensation again and zero-suppress, then the OFDM symbol that obtains is carried out the deinterleaving of Q road, OFDM successively and separate time-frequency resource allocating, rotation and separate and be in harmonious proportion decoding, obtain required data message.

The present invention is a kind of method that is used for the modulation diversity joint codes of ofdm system, and it is that (application number is: expansion 2008102264831) and improvement in applicant's application for a patent for invention of last year " a kind of signal diversity method of ofdm system ".Application for a patent for invention in 2008 is to obtain lifting and the improvement of diversity technique to transmission performance by two dimension rotation modulation, the present invention expands to multidimensional rotation modulation with this patented technology, can utilize modulation diversity better, binding time diversity, frequency diversity improve the performance of system again.

The present invention's innovative point technically is: in modulated process, comprehensive OFDM technology and the multidimensional rotation modulation technique of adopting, introduce the signal diversifying gain in the rotation modulation constellation, in-phase component (I road) that modulation symbol after make sending produces in transmission course and quadrature component (Q road) be independent transmission on each comfortable fading channel each other, again two components are realized that by the component interleaver of setting component interweaves, to eliminate the correlation of I road and Q road fading coefficients, the gain of obtaining modulation diversity; And by selecting the optimum anglec of rotation, the maximum lift on the obtained performance.In addition, also introduce the OFDM frequency diversity and the diversity that interweaves, in the transmission of fading channel, can effectively improve every performance of communication system, obtain to be better than the performance advantage of BICM-OFDM system on the whole.And the operating procedure of the inventive method is simple, practical, and effect is obvious, applicable to multiple coded modulation scheme, be specially adapted to the code word of high code check and different code length, well the frame error rate of low system, therefore, the present invention has good popularization and application prospect.

Description of drawings

Fig. 1 is each operating procedure flow chart of method of the present invention's modulation diversity joint codes of being used for ofdm system.

Fig. 2 (a) and (b) are respectively the time-frequency interlacing rule schematic diagram and the Q road frequency-domain-interleaving rule schematic diagrames of modulation symbol during four-dimensional rotation modulation Q road interweaves.

Fig. 3 (a) and (b) are respectively the two-dimensional coordinate system and the postrotational schematic diagrames thereof of QPSK planisphere.

Fig. 4 is the structure of time slot schematic diagram of ofdm system.

Fig. 5 (a) and (b) are respectively centralized and distributed two kinds of pattern diagram in the OFDM frame structure.

Fig. 6 is an OFDM time-frequency resource allocating mode schematic diagram in the embodiments of the invention.

Fig. 7 is the regular schematic diagram of time-frequency two-dimensional interleaver.

Fig. 8 is planisphere and the demodulation schematic diagram of rotation planisphere through forming behind the channel fading.

Fig. 9 (a) and (b) are respectively that the embodiment of the invention compares schematic diagram with adopting two kinds of transmission performance curves of Bit Interleave coded modulation BICM OFDM mode under 8/9 code check.

Embodiment

For making the purpose, technical solutions and advantages of the present invention clearer, the present invention is described in further detail below in conjunction with drawings and Examples.

Referring to Fig. 1, introduce the concrete operations step of method that the present invention is used for the modulation diversity joint codes of ofdm system, it is to adopt OFDM technology and multidimensional rotation modulation technique, and the component by rotation planisphere, modulation symbol interweaves, obtain the gain of signal diversifying, and then improve the performance of system.

Step 1, transmitting terminal are carried out initialization process to sending data: each user's transmission data are encoded respectively and modulate according to the coding of setting and modulation system, according to the anglec of rotation of setting the I road in-phase component and the Q road quadrature component of the symbolic vector piece of all users after modulating are carried out multidimensional rotation modulation again, then the symbolic vector piece after the rotation modulation is stored.This step 1 comprises following concrete operations content:

(11) transmitting terminal calculates the total G:G=OFDM_Num * OFDM_Length of the modulation symbol that all users send in each transmission course earlier, in the formula, OFDM_Num is the OFDM symbolic number that sends in each OFDM transmission course, and OFDM_Length is arranged on the modulation symbol number in each OFDM symbol; Calculate the modulation symbol of each user's transmission again and count S: $S=\frac{G}{P},$ In the formula, P is the total number of users of transmitting terminal;

In an embodiment, the OFDM frame structure of selecting is the frame structure of the tdd mode of agreement 3GPP TS 36.211 regulations, the modulation symbol number that comprises in each OFDM symbol period is: the number of OFDM symbol is in the each OFDM transmission course of OFDM_Length=1200: OFDM_Num=12, therefore, all users' modulation symbol sum G=14400 in the transmission course each time, the number of users P=20 of transmitting terminal, the modulation symbol number that each user sends is: S=720.

(12) calculate each modulation symbol according to order of modulation M and form, be i.e. M=2 by m bit mapping ^m, m=log then ₂M calculates each user's the code length N:N=S * m of transmission data behind coding; The information bit position long K:K=r * N of the transmission data of calculating each user again before coding, in the formula, code check r be span be (0,1] real number;

In an embodiment, modulation system is selected QPSK, 16QAM and 64QAM respectively for use, therefore order of modulation is respectively 4,16 and 64, the information bit of each modulation symbol correspondence is respectively 2,4 and 6, thereby the code length N that calculates after each user's the transmission digital coding is respectively 1440,2880 and 4320.

Because the code check r of embodiment is 8/9, the information bit length K that each user produces is respectively 1280,2560 and 3840; But, because the employing of the encoding scheme in the embodiment of the invention is the Turbo coding of agreement 3GPP TS36.212 regulation, so the Turbo information encoded position bit length of necessary protocol compliant 3GPP TS 36.212 regulations of information bit bit length K.Information bit bit length K at above-mentioned employing, if do not satisfy the Turbo information encoded position bit length of agreement 3GPP TS 36.212 regulations, just select immediate information bit bit length in the agreement for use, afterbody in these data replenishes zero again, reaches the information bit bit length K requirement that aforementioned calculation is come out.

(13) the K bit information that will send each user is encoded, and the code length N bit of each user after will encoding again behind definite corresponding gray mappings constellation pattern, carries out the corresponding symbol mapping according to the modulating mode requirement; And use symbolic vector u _iSymbol after the expression modulation, then the modulation symbol of all users' transmission data after modulation, be that the set that whole symbolic vectors are formed is u=(u ₁, u ₂..., u _G), and be called the modulation symbol vector block, in the formula, the sum of the modulation symbol that subscript G is ready for sending for all users;

What the embodiment of the invention adopted is the Turbo chnnel coding.

(14) adopt spin matrix RM that the symbolic vector piece after modulating is carried out multidimensional rotation modulation, obtain the modulation diversity gain: the symbolic vector piece x that establishes after rotation is modulated is: x=(x ₁, x ₂..., x _G), each symbolic vector x among this symbolic vector piece x then _iAll satisfy following formula: x _i'=RM * u _i'; In the formula, for N dimension rotation modulation, N is the natural number greater than 1, u _iBe the row vector of N dimension, the modulation symbol before the expression rotation modulation treatment, u _i' be u _iThe transposition column vector; x _iBe the row vector of N dimension, the modulation symbol after the expression multidimensional rotation modulation, x _i' be x _iThe transposition column vector; RM is the spin matrix on N rank, and the quadratic sum of its every row or every row all is 1, satisfies orthogonality between row vector or the column vector;

The dimension that symbolic vector piece after the present invention adopts spin matrix RM to modulation carries out multidimensional rotation modulation comprises 2 dimensions, 4 dimensions, 8 dimension or higher dimensions, still, and the calculation of complex of the rotation modulation of 8 dimensions or higher dimension, and advantage is not obvious; So what selection was maximum is 2 peacekeepings, 4 dimensions; Its concrete grammar is;

When selecting two dimension rotation modulation, each two-dimensional modulation symbolic vector is that in-phase component and the quadrature component by a modulation symbol constituted, and promptly rotates the in-phase component and the quadrature component of a modulation symbol vector of modulation treatment at every turn; Therefore, establishing each preceding modulation symbol vector of two dimension rotation modulation treatment is u _i=A+Bj, wherein, A is u _iIn-phase component, B is u _iQuadrature component; Spin matrix $\mathrm{RM}=\left(\begin{array}{cc}\cos \mathrm{\θ}& \sin \mathrm{\θ}\\ -\sin \mathrm{\θ}& \cos \mathrm{\θ}\end{array}\right),$ θ is the anglec of rotation of setting, and its span is

Through the symbolic vector after the two dimension rotation modulation treatment is x _iDuring=X+Yj, then $\left(\begin{array}{c}X\\ Y\end{array}\right)=\mathrm{RM}\×\left(\begin{array}{c}A\\ B\end{array}\right),$ Promptly $\left(\begin{array}{c}X\\ Y\end{array}\right)=\left(\begin{array}{cc}\cos \mathrm{\θ}& \sin \mathrm{\θ}\\ -\sin \mathrm{\θ}& \cos \mathrm{\θ}\end{array}\right)\left(\begin{array}{c}A\\ B\end{array}\right);$

When selecting four-dimensional rotation modulation, each four-dimensional modulation symbol is that in-phase component and the quadrature component by two adjacent modulation symbol vectors constituted, and promptly rotates two adjacent modulation symbol vectors of modulation treatment in-phase component and quadrature component separately at every turn; So two modulation symbol vectors establishing before the four-dimensional rotation modulation treatment are respectively A+Bj and C+Dj, when the value of these two the modulation symbol vector correspondences after the four-dimensional rotation modulation of process is respectively X+Yj and Z+Wj, then $\left(\begin{array}{c}X\\ Y\\ Z\\ W\end{array}\right)=\mathrm{RM}\×\left(\begin{array}{c}A\\ B\\ C\\ D\end{array}\right),$ In the formula,

$\mathrm{RM}=\left(\begin{array}{cccc}\cos {\mathrm{\θ}}_1\cos {\mathrm{\θ}}_2& \sin {\mathrm{\θ}}_1\cos {\mathrm{\θ}}_2& \cos {\mathrm{\θ}}_1\sin {\mathrm{\θ}}_2& \sin {\mathrm{\θ}}_1\sin {\mathrm{\θ}}_2\\ -\sin {\mathrm{\θ}}_1\cos {\mathrm{\θ}}_2& \cos {\mathrm{\θ}}_1\cos {\mathrm{\θ}}_2& -{\sin \mathrm{\θ}}_1\sin {\mathrm{\θ}}_2& \cos {\mathrm{\θ}}_1\sin {\mathrm{\θ}}_2\\ -\cos {\mathrm{\θ}}_1\sin {\mathrm{\θ}}_2& -\sin {\mathrm{\θ}}_1\sin {\mathrm{\θ}}_2& \cos {\mathrm{\θ}}_1\cos {\mathrm{\θ}}_2& \sin {\mathrm{\θ}}_1\cos {\mathrm{\θ}}_2\\ \sin {\mathrm{\θ}}_1\sin {\mathrm{\θ}}_2& -\cos {\mathrm{\θ}}_1\sin {\mathrm{\θ}}_2& -\sin {\mathrm{\θ}}_1\cos {\mathrm{\θ}}_2& \cos {\mathrm{\θ}}_1\cos {\mathrm{\θ}}_2\end{array}\right),$ θ ₁And θ ₂Be respectively the anglec of rotation of setting, its span is

Referring to Fig. 3, be modulated to example with two-dimentional quaternary PSK QPSK, introduce the comparable situation of rotation modulation front and back planisphere.Because QPSK is mapped as 1 symbolic vector with per 2 bits, have 4 kinds of possible bit combinations and corresponding symbol vector value, Fig. 3 (a) is depicted as gray mappings planisphere under the common modulation case, wherein A, B are respectively the projection of each constellation point on real part axle and imaginary part axle, and its numerical value is respectively

Fig. 3 (b) is the planisphere that Fig. 3 (a) forms through θ degree rotation modulation back, wherein X, Y are respectively the projection of rotation modulation each constellation point of back on real part axle and imaginary part axle, after the rotation modulation operation, the determined constellation point numerical value of X, Y is equivalent to Fig. 3 (a) θ degree that turns clockwise.In the embodiment of the invention, the θ value of two-dimentional quaternary PSK QPSK modulation is $\mathrm{\θ}=\arctan \left(\frac{1}{2}\right)=0.4636$ (radian), twiddle factor cos θ=0.8944, sin θ=0.4472 supposes that the symbol before the rotation modulation is A+Bj, the symbol after the rotation modulation is X+Yj, then basis $\left(\begin{array}{c}X\\ Y\end{array}\right)=\left(\begin{array}{cc}0.8944& 0.4472\\ -0.4472& 0.8944\end{array}\right)\left(\begin{array}{c}A\\ B\end{array}\right),$ The symbol that can access after rotation is modulated is; Adopt the θ value of 16QAM to be $\mathrm{\θ}=\arctan \left(\frac{1}{3}\right)=0.3218$ (radian); Adopt the θ value of 64QAM to be $\mathrm{\θ}=\arctan \left(\frac{1}{4}\right)=0.245$ (radian); Thereby obtain following rotation modulation matrix:

(15) will finish the symbolic vector piece x of rotation after the modulation treatment and deposit memory in.

Step 2, transmitting terminal are according to the symbolic vector piece distribution OFDM running time-frequency resource of the OFDM pattern of setting to all users in the memory, each user's symbolic vector piece is evenly distributed in each OFDM symbol successively, and the symbolic vector piece to each user in the OFDM symbol carries out Q road interleaving treatment again.

This step 2 comprises following concrete operations content:

(21) transmitting terminal is to all users' symbolic vector piece x, according to the centralized or distributed OFDM mode assignments OFDM running time-frequency resource of setting, wherein, time resource is the time slot that the OFDM symbol sends successively, and frequency resource is to send the shared subcarrier bandwidth of each OFDM symbol; Each OFDM symbol occupies a time slot, and each modulation symbol in the OFDM symbol occupies a subcarrier, so the modulation symbol number OFDM_Length that comprises in each OFDM symbol also is the occupied subcarrier number of each OFDM symbol; Just the number of modulation symbols L with each included in each OFDM symbol user is made as: $L=\frac{\mathrm{OFDM}\_\mathrm{Length}}{P}=\frac{S}{\mathrm{OFDM}\_\mathrm{Num}};$ In the formula, OFDM_Length is the whole number of modulation symbols in each OFDM symbol, and P is all users' a sum, and S is the modulation symbol number that sends in the each transmission course of each user, and OFDM_Num is the OFDM symbolic number that sends in each OFDM transmission course; Thereby make each OFDM symbol comprise L * P modulation symbol, it occupies OFDM_Length subcarrier on frequency domain; Total OFDM_Num OFDM symbol occupies OFDM_Num time slot on time domain.

Referring to Fig. 4, introduce in the embodiment of the invention, $N_{\mathrm{sc}}^{\mathrm{RB}}=12,$ N _symb＝6，N _RB＝100，T _slot＝5ms。This embodiment operates two time slots together, so in each OFDM transmission course, OFDM symbolic number OFDM_Num=12, the modulation symbol that comprises in each OFDM symbol is counted OFDM_Length=1200, no matter adopt centralized or distributed, all be that symbolic vector piece with the user is stored in the structure of time slot according to Fig. 4 mode, distribution through above-mentioned OFDM running time-frequency resource, 720 modulation symbols of each user are evenly distributed on 12 OFDM symbols, and promptly each OFDM symbol all contains 60 modulation symbols of each user.

Referring to Fig. 5 (a), introduce the method that the user symbol vector block is write structure of time slot according to centralized OFDM pattern.The square that shading is identical among the figure is represented same user's symbolic vector piece, with L=720 symbol in the same user symbol vector block with $N_{\mathrm{sc}}^{\mathrm{RB}}=12$ Be divided into one group, have 60 groups; The representative of each square comprises a group of 12 modulation symbols among the figure, after user's symbolic vector piece is divided into group, is that a row column major order is arranged for per 5 groups with same user's symbolic vector piece successively, has 2 * N _SymbRow, promptly each user's 60 component chunks can change into 5 * 12 matrix, and each element of this matrix is a grouping that comprises 12 modulation symbols.By that analogy, after successively 20 users' symbolic vector piece being arranged in the manner described above, formed 100 * 12 matrix, again according to shown in the arrow, column major order takes out grouping block and is stored in the structure of time slot memory of Fig. 3 (a).

Referring to Fig. 5 (b), introduce the method that the user symbol vector block is write structure of time slot according to distributed OFDM pattern.Earlier by above-mentioned with quadrat method with user's symbolic vector piece with 12 modulation symbols be one group divide into groups after, successively 60 grouping block of each user are pressed the row sequence arrangement, each user's symbolic vector blocking is 1 * 60 matrix, then 20 users' symbolic vector piece has been formed 20 * 60 matrix, according to shown in the arrow, column major order takes out again.After promptly successively first group of each user being taken out, continue to get each user again second group, by that analogy, up to having got the 60th group of 20 users.

(22) according to the dimension of the selected multidimensional of abovementioned steps rotation modulation, the symbolic vector piece of each user in the OFDM symbol is carried out corresponding Q road interleaving treatment: the time-frequency of modulation symbol vector interweaves, Q road frequency-domain-interleaving and Q road time-frequency two-dimensional interleaver interweave.

When transmitting terminal carries out the Q road when interweaving according to centralized OFDM pattern, if adopt two dimension rotation modulation, in the then described step (22), the time-frequency of not carrying out the modulation symbol vector interweaves and the operation of Q road frequency-domain-interleaving, directly carries out the interlace operation of Q road time-frequency two-dimensional interleaver; If adopt the rotation modulation of four-dimensional or higher dimension, then described step (22) comprises following content of operation:

(221) symbolic vector of transmitting terminal after to the rotation of same user in each OFDM symbol period modulation carried out the time-frequency interleaving treatment, and the time-frequency interlacing rule is: the symbolic vector after each user's the rotation modulation is stored in according to writing mode line by line

Behind the interleaver of form, again according to taking out by the row mode, with the conversion that interweaves of the time-frequency by this symbolic vector, reduce in each rotation modulation the time domain between two adjacent-symbol vectors and the correlation of frequency domain, in the formula, D is the dimension of multidimensional rotation modulation.

Among the embodiment, if when adopting two dimension rotation modulation, execution in step (221) not then; If adopt four-dimensional rotation modulation, then the time-frequency that carries out modulation symbol according to step (221) interweaves, and simultaneously treated two symbols of once four-dimensional rotation modulation are disperseed to be placed on to be separated by

Two frequencies on, make these two symbols interval of 30 symbols that is separated by, thereby reduce once in the four-dimensional rotation modulation treatment the time domain between two adjacent-symbols and the correlation of frequency domain.

(222) the Q road quadrature component of the symbolic vector after the time-frequency of each user in each OFDM symbol period is interweaved is carried out frequency-domain-interleaving in regular turn and is handled, and the frequency-domain-interleaving rule is that the modulation symbol vector of the L that belongs to same user in each OFDM symbol is handled together: earlier with in this L symbolic vector, be spaced apart The Q road component of D symbolic vector be made as one group, total

Group; Again the circulation to the right in regular turn of the Q road component in every group is moved one, i.e. Q _fMove to

The position, and

Move to

The position, Then move to

The position, correspondingly, last Q road component then moves to Q _fThe position, just: Q _f→ Q _F+L/D→ Q _F+2L/D→ Q _F+3L/D→ ... → Q _fAnd then with the new symbolic vector of Q road quadrature component merging composition after I road in-phase component and the displacement.

Among the embodiment, if when adopting two dimension rotation modulation, also execution in step (222) not; If adopt four-dimensional rotation modulation, then carry out the frequency-domain-interleaving of Q road component.In each OFDM symbol in 60 modulation symbols of same user, the Q road branch that is spaced apart four modulation symbols of 15 symbols is measured and is done one group, with the Q road component in this group move to right successively cyclic shift, that is: Q ₁→ Q ₁₅→ Q ₃₀→ Q ₄₅→ Q ₁, carry out identical operations to all the other every group successively.

(223) according to the time-frequency two-dimensional interlacing rule of setting, each user is evenly distributed in whole S modulation symbols that in each OFDM symbol, at every turn send carries out interleaving treatment, make quadrature component and its in-phase component of any one modulation symbol in each this S modulation symbol that sends of each user after interweaving all uncorrelated mutually as much as possible on time and frequency, even the distance of quadrature component and its in-phase component is far away as far as possible.On the time domain, an OFDM symbol takies a time slot in time, according to same user's S the running time-frequency resource that symbol takies, be on the time domain location interval OFDM_Num time slot, promptly at interval the distance between two frequencies of OFDM_Num OFDM symbol farthest, correlation is the most weak; Be on the frequency domain location interval L subcarrier bandwidth, promptly at interval the distance between two signaling points of L symbol farthest, correlation is the most weak, still, in order to guarantee all frequencies substep equably, selection is satisfied on the time domain simultaneously

On individual time slot and the frequency domain

The symbol of individual subcarrier bandwidth distance.

When transmitting terminal carries out the Q road when interweaving according to distributed OFDM pattern, after first operation rules according to above-mentioned centralized OFDM pattern calculates step (22) result, again centralized result of calculation distributed frequency point allocation mode according to step (21) on frequency domain is come the even expansion of result, the invariant position of time domain, and, the relative position of frequency domain is also constant, has just changed the absolute position of subcarrier frequency.

Time-frequency two-dimensional interlacing rule of the present invention is: will this same user, the modulation symbol of W subcarrier bandwidth is made as one group at interval on frequency domain, supposes that again choosing two sequence numbers is f ₁, f ₂Subcarrier, wherein, f ₂=f ₁+ W, W are two sub-carrier frequency point f ₁And f ₂Bandwidth granularity; $W=\frac{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">L</figure-callout>}}{2},$ And the position coordinates of establishing the Q road component of each modulation symbol is (f, t), represent that f modulation symbol in each OFDM symbol is positioned at f sub-carrier frequency point on the frequency domain and t OFDM symbol on the time domain, natural number t is the sequence number of OFDM symbol, and its maximum is OFDM_Num; The Q road component of order choice of modulation symbol is promptly chosen f in the 1st the OFDM symbol earlier earlier ₁The Q road component of individual modulation symbol is chosen at interval on the time domain again

Of individual OFDM symbol

F in the individual OFDM symbol ₂The Q road component of individual modulation symbol; Then choose f in the 2nd the OFDM symbol ₁The Q road component of individual modulation symbol is chosen at again

F in the individual OFDM symbol ₂The Q road component of individual modulation symbol continues to choose f in the 3rd the OFDM symbol ₁The Q road component of individual modulation symbol chooses again

F in the individual OFDM symbol ₂The Q road component of individual modulation symbol, and the like, according on time domain,, select again to be separated by with it from the 1st OFDM symbol choosing

Of individual OFDM symbol

Individual OFDM symbol, and then increase the 2nd OFDM symbol of a selection, select again to be separated by with it

Of individual OFDM symbol Individual OFDM symbol, and the like, choose from always

Individual OFDM symbol is selected to be separated by with it again (OFDM_Num) individual OFDM symbol of individual OFDM symbol on frequency domain, is exactly f ₁, f ₂Alternate selection; Like this, before interweaving, the position coordinates of the Q road component of each modulation symbol in each OFDM symbol is respectively:

$\{({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="A2009100911630029H1.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,1),({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\frac{\mathrm{OFDM}\_\mathrm{<figure-callout\; id="2"\; label="Num"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">Num</figure-callout>}}{2}+1),({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="A2009100911630029H1.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,2),({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\frac{\mathrm{OFDM}\_\mathrm{<figure-callout\; id="2"\; label="Num"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">Num</figure-callout>}}{2}+2),\&CenterDot;\&CenterDot;\&CenterDot;,({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="A2009100911630029H1.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}),({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\mathrm{OFDM}\_\mathrm{Num})\},$ After the time-frequency two-dimensional of process Q road component interweaved, the frequency domain that it is occupied and the position coordinates of time domain were that one result is moved in the Q road component circulation to the right in regular turn of original OFDM symbol just, are $\{({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\frac{\mathrm{OFDM}\_\mathrm{<figure-callout\; id="2"\; label="Num"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">Num</figure-callout>}}{2}+1),({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="A2009100911630029H1.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,2),({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\frac{\mathrm{OFDM}\_\mathrm{<figure-callout\; id="2"\; label="Num"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">Num</figure-callout>}}{2}+2),\&CenterDot;\&CenterDot;\&CenterDot;,({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="A2009100911630029H1.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}),({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\mathrm{OFDM}\_\mathrm{Num}),({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="A2009100911630029H1.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,1)\};$ Therefore, the I road component after the process time-frequency two-dimensional interweaves and the time interval minimum of Q road component are The time length of field OFDM_Num * T that is about the OFDM symbol _sHalf, wherein, T _sIt is the transmission time of OFDM symbol; Frequency domain interval be corresponding ofdm system frequency domain length 1/2nd; Thereby make the low time-frequency two-dimensional of computation complexity interweave and fully to effectively utilize the frequency diversity and the time diversity of ofdm system, and realize combined optimization with modulation diversity.

Referring to Fig. 7, introduce the time-frequency two-dimensional interlacing rule that the embodiment of the invention adopts in this step (223), this figure is the wherein signal that interweaves of Q road, and concrete grammar is: the Q road component that each user is evenly distributed in the symbolic vector piece in each OFDM symbol interweaves; Each user's symbolic vector piece comprises S=720 modulation symbol among the embodiment, be evenly distributed in 12 OFDM symbols according to time-domain resource, 60 modulation symbols that comprise each user in each OFDM symbol, promptly carrying out the frequency domain resource that Q road component that time-frequency interweaves occupies is 60 subcarriers, and time-domain resource is 12 OFDM symbols; According to mentioned above principle, the frequency of interval 〉=5 OFDM symbols on 30 subcarrier bandwidth in interval and the time domain on the frequency domain is got one group in work; Get subcarrier bandwidth and be numbered f ₁, f ₂, f wherein ₁=1...60, f ₂=(f ₁+ 30) mod 60; And make (f, t) the Q road component of representing this modulation symbol occupies f subcarrier on frequency domain, occupies t OFDM symbol on time domain, t=1,2...12; Then on time and frequency, the imaginary part of symbol is carried out place-exchange according to following rule: (f ₁, 1) → (f ₂, 7), (f ₂, 7) → (f ₁, 2), (f ₁, 2) → (f ₂, 8), (f ₂, 8) → (f ₁, 3), (f ₁, 3) → (f ₂, 9), (f ₂, 9) → (f ₁, 4), (f ₁, 4) → (f ₂, 10), (f ₂, 10) → (f ₁, 5), (f ₁, 5) → (f ₂, 11), (f ₂, 11) → (f ₁, 6), (f ₁, 6) → (f ₂, 12), (f ₂, 12) → (f ₁, 1).

Step 3, transmitting terminal are according to default OFDM modulation length and IFFT computing length, respectively to not enough IFFT computing length in each OFDM symbol the position long zero padding, again each the OFDM symbol after the zero padding is comprised the IFFT computing and add the OFDM processing of cyclic prefix CP, send data then.

This step 3 comprises following concrete operations content:

(31) respectively to not enough IFFT computing length in each OFDM symbol the position long zero padding after, again each the OFDM symbol after the zero padding is carried out the IFFT computing respectively according to the following equation: $x\left(n\right)=\frac{1}{\sqrt{N}}\underset{k=0}{\overset{N-1}{\mathrm{\&Sigma;}}}X\left(k\right){\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">e</figure-callout>}}^j,$ In the formula, N is a sub-carrier number, and X (k) is the complex signal of setting under the modulating mode, and x (n) is the sampling of OFDM symbol in time domain, and the definition of the j of imaginary unit is: j ²=-1, k is the sequence number of the symbolic vector in the OFDM symbol, and its span is the nonnegative integer of [0, N-1].

Referring to Fig. 6, further introduce and distribute OFDM running time-frequency resource situation in the embodiment of the invention: transverse axis is represented the distribution condition of OFDM symbol on subcarrier bandwidth, and the longitudinal axis is represented the distribution condition of OFDM symbol on time slot.According to each OFDM symbol lengths shown in Figure 4 is 1200, and each OFDM transmission course is handled 12 OFDM symbols, takies 2048 OFDM subcarrier bandwidth; FFT that this embodiment chooses or the length of IFFT are 2048, are 1200 modulation symbols to length in each the OFDM symbol after redistributing, and replenish 848 zero, so that its length equals the length 2048 of IFFT.

(32) the OFDM symbol after each process IFFT computing is added CP respectively, eliminate the intersymbol interference that the multipath channel transmission causes; The concrete operations content is: μ symbol of each OFDM symbol afterbody copied the front end that is added into this OFDM symbol, and wherein, μ is the length of CP.

CP length μ among the embodiment is 512, and the sign bit length of adding after CP handles increases to 2560.

(33) send each OFDM symbol successively.

After step 4, receiving terminal receive data, the OFDM that separates that CP and fast Fourier transform FFT computing are removed to this data block symbols by elder generation handles, carry out phase compensation again and zero-suppress, then the OFDM symbol that obtains is carried out the deinterleaving of Q road, OFDM successively and separate time-frequency resource allocating, rotation and separate and be in harmonious proportion decoding, obtain required data message.This step 4 comprises following concrete operations content:

(41) after receiving terminal received data, it is separated OFDM handle: earlier each the OFDM symbol that receives is removed CP respectively, each the OFDM symbol that is about to receive was deleted μ symbol of its head respectively; Again each OFDM symbol is carried out fast Fourier transform FFT computing respectively according to the following equation: $X\left(k\right)=\frac{1}{\sqrt{N}}\underset{k=0}{\overset{N-1}{\mathrm{\&Sigma;}}}x\left(n\right)e^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;}}{N}\mathrm{kn}},$ In the formula, N is a sub-carrier number, and X (k) is the complex signal of setting under the modulating mode, and x (n) is the sampling of OFDM symbol in time domain, and the definition of the j of imaginary unit is: j ²=-1, k is the sequence number of the symbolic vector in the OFDM symbol, and its span is the nonnegative integer of [0, N-1]; Then, the OFDM symbol after the conversion is stored;

Among the embodiment, 512 of the Cyclic Prefix of 2560 symbol heads at every turn receiving are all deleted.

(42) the OFDM symbol after the conversion is carried out phase compensation, so that eliminate the influence of multipath transmission to data according to channel estimation value; The phase compensation formula is: $y\left(t\right)=\frac{x\left(t\right)\&times;\stackrel{\&OverBar;}{h\left(t\right)}}{\left|h\left(t\right)\right|};$ In the formula, x (t) is the symbolic vector in each OFDM symbol, h (t), h (t) and | h (t) | be respectively channel guess value, the conjugation of channel guess value and mould;

(43) each the OFDM symbol after the phase compensation is removed zero, promptly delete position long add zero of step (31), then, each OFDM symbol is stored for coupling IFFT computing length;

This step among the embodiment is 848 zero-bits that deletion is added in order to mate IFFT length.

(44) the centralized or distributed OFDM pattern of selecting according to step (13) that the multidimensional rotation is modulated and step (21) is selected, symbolic vector in each OFDM symbol is carried out the deinterleaving of corresponding Q road handle, promptly carry out reverse process according to the rule of correspondence of step (22).

When receiving terminal carries out the deinterleaving of Q road according to centralized OFDM pattern, if adopt two dimension rotation modulation, in the then described step (44), only carry out the deinterleaving operation of Q road time-frequency two-dimensional interleaver, do not carry out the time-frequency deinterleaving of modulation symbol vector and the operation of Q road frequency domain deinterleaving; If adopt the rotation modulation of four-dimensional or higher dimension, then this step (44) comprises following content of operation:

(441) according to the reverse process method of the time-frequency two-dimensional interlacing rule of step (223) the Q road component of symbolic vector is carried out deinterleaving: the Q road component of order choice of modulation symbol earlier, promptly choose the earlier

F in the individual OFDM symbol ₂The Q road component of individual modulation symbol is chosen f in the 2nd the OFDM symbol again ₁The Q road component of individual modulation symbol then chooses F in the individual OFDM symbol ₂The Q road component of individual modulation symbol is chosen f in the 3rd the OFDM symbol again ₁The Q road component of individual modulation symbol continues to choose

F in the individual OFDM symbol ₂The Q road component of individual modulation symbol is chosen f in the 3rd the OFDM symbol then ₁The Q road component of individual modulation symbol, and the like; On time domain according to from

Individual OFDM symbol selects, and selects the 2nd OFDM symbol again, then selects to be separated by with it

Individual OFDM symbol

Individual OFDM symbol is selected from the 3rd OFDM symbol of 1 OFDM symbol of the 2nd increase again, selects then to be separated by with it

Individual OFDM symbol

Individual OFDM symbol, and the like, choose from Individual OFDM symbol is selected to be separated by with it again

(OFDM_Num) individual OFDM symbol of individual OFDM symbol is chosen the 1st OFDM symbol at last; On frequency domain f ₂, f ₁Alternate selection; Like this, before interweaving, the position coordinates of the Q road component of each modulation symbol in each OFDM symbol is respectively:

$\{({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\frac{\mathrm{OFDM}\_\mathrm{<figure-callout\; id="2"\; label="Num"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">Num</figure-callout>}}{2}+1),({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="A2009100911630029H1.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,2),({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\frac{\mathrm{OFDM}\_\mathrm{<figure-callout\; id="2"\; label="Num"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">Num</figure-callout>}}{2}+2),\&CenterDot;\&CenterDot;\&CenterDot;,({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="A2009100911630029H1.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}),({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\mathrm{OFDM}\_\mathrm{Num}),({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="A2009100911630029H1.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,1)\},$

After the time-frequency two-dimensional deinterleaving through Q road component, the frequency domain that it is occupied and the position coordinates of time domain are that one result is moved in the Q road component circulation left in regular turn of original OFDM symbol just, are:

$\{({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="A2009100911630029H1.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,1),({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\frac{\mathrm{OFDM}\_\mathrm{<figure-callout\; id="2"\; label="Num"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">Num</figure-callout>}}{2}+1),({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="A2009100911630029H1.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,2),({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\frac{\mathrm{OFDM}\_\mathrm{<figure-callout\; id="2"\; label="Num"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">Num</figure-callout>}}{2}+2),\&CenterDot;\&CenterDot;\&CenterDot;,({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="A2009100911630029H1.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}),({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\mathrm{OFDM}\_\mathrm{Num})\}$

Make Q road quadrature component symbol on time and frequency, all carry out place-exchange according to above-mentioned rule

$({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="A2009100911630029H1.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,1)\&RightArrow;({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\mathrm{OFDM}\_\mathrm{Num}),({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\mathrm{OFDM}\_\mathrm{Num})\&RightArrow;({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="A2009100911630029H1.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}),$

$({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="A2009100911630029H1.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2})\&RightArrow;({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\mathrm{OFDM}\_\mathrm{Num}-1),({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\mathrm{OFDM}\_\mathrm{Num}-1)\&RightArrow;({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="A2009100911630029H1.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}-1),$

$({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="A2009100911630029H1.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}-1)\&RightArrow;({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\mathrm{OFDM}\_\mathrm{Num}-2),......,({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\mathrm{OFDM}\_\mathrm{Num}/2+2)\&RightArrow;({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="A2009100911630029H1.png,A2009100911630033H1.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,2),$

(f ₁，2)→(f ₂，OFDM_Num/2+1)，(f ₂，OFDM_Num/2+1)→(f ₁，1)。

Among the embodiment, separating according to step (451) that Q road time-frequency two-dimensional interweaves is that imaginary part and real part with belonging to same modulation symbol originally mates reduction, and concrete grammar is: will be on the frequency domain get more than or equal to the frequency of 5 OFDM symbols at interval on 30 subcarrier bandwidth and the time domain at interval and do one group; Get subcarrier bandwidth and be numbered f ₁, f ₂, f wherein ₁=1...60, f ₂=(f ₁+ 30) mod 60; And make (f, t) expression symbol Q road component occupies f subcarrier on frequency domain, occupies t OFDM symbol on time domain, t=1,2 ..., 12; Then on time and frequency, the imaginary part of symbol is carried out place-exchange according to following rule: (f ₁, 1) → (f ₂, 12), (f ₂, 12) → (f ₁, 6), (f ₁, 6) → (f ₂, 11), (f ₂, 11) → (f ₁, 5), (f ₁, 5) → (f ₂, 10), (f ₂, 10) → (f ₁, 4), (f ₁, 4) → (f ₂, 9), (f ₂, 9) → (f ₁, 3), (f ₁, 3) → (f ₂, 8), (f ₂, 8) → (f ₁, 2), (f ₁, 2) → (f ₂, 7), (f ₂, 7) → (f ₁, 1).

(442) according to the reverse process method of step (222) the Q road component of symbolic vector is separated frequency-domain-interleaving, its rule is: in same user's L the symbolic vector, be spaced apart in each OFDM symbol

The Q road component of D symbolic vector be made as one group, the Q road component in this group circulation is left successively moved one, the imaginary part and the real part that then will belong to the prosign vector originally mate reduction.

Among the embodiment, if adopt two dimension rotation modulation, do not carry out this step (452), if adopt four-dimensional rotation modulation, then the concrete grammar of separating Q road frequency-domain-interleaving according to this step (452) is: with 60 symbols in the symbolic vector of same user in the OFDM symbol, the Q road branch that is spaced apart four symbols of 15 is measured and is done one group, with the Q road component cyclic shift that moves to left successively in this group, the imaginary part and the real part that then will belong to prosign originally mate reduction, and the Q road component to all the other each groups carries out identical operations successively.

(443) according to the reverse process method of step (221) symbolic vector is carried out the time-frequency deinterleaving, its rule is: to each user's symbolic vector according to be stored in by the row writing mode with

Behind the interleaver of form, take out according to row-by-row system again, like this, in the symbolic vector piece, be separated by

Two symbols just be reduced and be placed on the adjacent position, finish the time-frequency deinterleaving conversion of symbolic vector.

Among the embodiment, if adopt two dimension rotation modulation, do not carry out this step (453), if adopt four-dimensional rotation modulation, then separating the concrete grammar that time-frequency interweaves according to this step (453) is: in 60 modulation symbols of each user in an OFDM symbol, be dispersed in 30 two symbols of being separated by and be put into position adjacent, thus the position of four components before the once four-dimensional rotation modulation treatment of reduction.

(45) proceed OFDM and separate time-frequency resource allocating operation: with each user step (21) be distributed in whole OFDM symbols on the OFDM running time-frequency resource all L * P modulation symbol according to the contrary operation of this step in proper order, be reduced to all users' of serial symbolic vector again.

(46) adopt the maximum likelihood demodulation mode that the symbolic vector that OFDM separates after the time-frequency resource allocating is rotated demodulation: being demodulation reference constellation figure through the rotation planisphere after the multipath channel, the Euclidean distance of each constellation point among each symbolic vector in the symbolic vector set that calculating receives and its reference constellation figure, obtain shining upon the log-likelihood ratio of each bit that becomes each symbolic vector respectively, be used for decoding.

Referring to Fig. 8, introduce and use planisphere and the demodulation mode thereof of rotation modulation constellation through forming after the fading channel.The signal on I road and Q road has different channel fading amplitude distortions respectively among the figure, and the channel fading range coefficient of establishing the I road is | and h2|, the channel fading range coefficient on Q road be | h1|.The mode of its demodulation is: at first calculate the distance of acceptance point to each constellation point, i.e. d shown in the figure ₁～d ₄, calculate the log-likelihood ratio of every bit of this symbol correspondence again.With first bit is example, and according to this planisphere, the 1st is that 0 bit combination is 00 and 01 in four constellation point, and the distance of its correspondence is d ₁And d ₄, the 1st is that 1 bit combination is 10 and 11, the distance of its correspondence is d ₂And d ₃Thereby the log-likelihood ratio that obtains this bit is:

$\log \frac{\exp (-\frac{{{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="A2009100911630029H1.png,A2009100911630033H1.png"\; state="\{\{state\}\}">d</figure-callout>}}_1}^2}{2{\mathrm{\&sigma;}}^2})+\exp (-\frac{{{\mathrm{<figure-callout\; id="4"\; label="d"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">d</figure-callout>}}_4}^2}{2{\mathrm{\&sigma;}}^2})}{\exp (-\frac{{{\mathrm{<figure-callout\; id="3"\; label="d"\; filenames="A2009100911630033H1.png,A2009100911630034H1.png"\; state="\{\{state\}\}">d</figure-callout>}}_3}^2}{2{\mathrm{\&sigma;}}^2})+\exp (-\frac{{{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="A2009100911630029H2.png,A2009100911630033H1.png"\; state="\{\{state\}\}">d</figure-callout>}}_2}^2}{2{\mathrm{\&sigma;}}^2})}.$

(47) according to the corresponding decoded mode of coding mode selection, every group of OFDM symbol substitution is reduced to K the information bit that the position is long, all flow process finishes.

The embodiment of the invention test that the applicant finishes adopts Turbo as its chnnel coding.Each parameter declaration of this embodiment is as follows: code check is 8/9, and channel model is TU; Decoded mode is Log-Map; Maximum iteration time=8; IFFT length or FFT length are 2048, and CP length is 512; Modulation system is under the QPSK condition, information bit length 1280; Modulation system is under the 16QAM condition, information bit length 2560; Modulation system is under the 64QAM condition, information bit length 3840.

Fig. 9 (a) and (b) be respectively the embodiment of the invention and Bit Interleave coded modulation BICMOFDM mode at present commonly used be 8/9 o'clock transmission performance curve comparison diagram at code check, both all adopt the Turbo coding.Fig. 9 (a) is the performance curve that adopts under the centralized QPSK model frame structure.Curve among this Fig. 9 (a) is compared, when adopting QPSK, when frame error rate is 10E-2, four-dimensional rotation Modulation OFDM Turbo has nearly 5 dB than the performance boost of bit interweaving encoding Modulation OFDM Turbo, the rotation Modulation OFDM Turbo of two dimension than the performance boost of bit interweaving encoding Modulation OFDM Turbo also greater than 3.5 dB, be the lifting of nearly 4dB.Fig. 9 (b) is the performance curve that adopts under the distributed QPSK model frame of the 16QAM structure.Curve among this Fig. 9 (b) is compared, when adopting 16QAM, when frame error rate is 10E-2, four-dimensional rotation Modulation OFDM Turbo has nearly 4dB than the performance boost of bit interweaving encoding Modulation OFDM Turbo, and the rotation Modulation OFDM Turbo of two dimension also has 3dB than the performance boost of bit interweaving encoding Modulation OFDM Turbo.

Therefore, test of the present invention is successful, has realized goal of the invention.

Claims (10)

1, a kind of method that is used for the modulation diversity joint codes of orthogonal frequency ofdm system is characterized in that, described method comprises following operating procedure:

(1) transmitting terminal carries out initialization process to sending data: each user's transmission data are encoded respectively and modulate according to the coding of setting and modulation system, according to the anglec of rotation of setting the I road in-phase component and the Q road quadrature component of the symbolic vector piece of all users after modulating are carried out multidimensional rotation modulation again, then the symbolic vector piece after the rotation modulation is stored;

(2) transmitting terminal is according to the symbolic vector piece distribution OFDM running time-frequency resource of the OFDM pattern of setting to all users in the memory, each user's symbolic vector piece is evenly distributed in each OFDM symbol successively, and the symbolic vector piece to each user in the OFDM symbol carries out Q road interleaving treatment again;

(3) transmitting terminal is according to default OFDM modulation length and inverse fast fourier transform IFFT computing length, respectively to not enough IFFT computing length in each OFDM symbol the position long zero padding, again each the OFDM symbol after the zero padding is comprised the IFFT computing and add the OFDM processing of cyclic prefix CP, send data then;

(4) after receiving terminal receives data, the OFDM that separates that CP and fast Fourier transform FFT computing are removed to this data block symbols by elder generation handles, carry out phase compensation again and zero-suppress, then the OFDM symbol that obtains is carried out the deinterleaving of Q road, OFDM successively and separate time-frequency resource allocating, rotation and separate and be in harmonious proportion decoding, obtain required data message.

2, method according to claim 1 is characterized in that, described step (1) further comprises following content of operation:

(11) transmitting terminal calculates the total G:G=OFDM_Num * OFDM_Length of the modulation symbol that all users send in each transmission course earlier, in the formula, OFDM_Num is the OFDM symbolic number that sends in each OFDM transmission course, and OFDM_Length is the modulation symbol number that is provided with in each OFDM symbol; Calculate the modulation symbol of each user's transmission again and count S: $S=\frac{G}{P},$ In the formula, P is the total number of users of transmitting terminal;

(12) calculate each modulation symbol according to order of modulation M and form, be i.e. M=2 by m bit mapping ^m, m=log then ₂M calculates each user's the code length N:N=S * m of transmission data behind coding; The information bit position long K:K=r * N of the transmission data of calculating each user again before coding, in the formula, code check r be span be (0,1] real number;

(13) the K bit information that will send each user is encoded, and the code length N bit of each user after will encoding again behind definite corresponding gray mappings constellation pattern, carries out the corresponding symbol mapping according to the modulating mode requirement; And use symbolic vector u _iSymbol after the expression modulation, then the modulation symbol of all users' transmission data after modulation, be that the set that whole symbolic vectors are formed is u=(u ₁, u ₂..., u _G), and be called the modulation symbol vector block, in the formula, the sum of the modulation symbol that subscript G is ready for sending for all users;

(14) adopt spin matrix RM that the symbolic vector piece after modulating is carried out multidimensional rotation modulation, obtain the modulation diversity gain: the symbolic vector piece x that establishes after rotation is modulated is: x=(x ₁, x ₂..., x _G), each symbolic vector x among this symbolic vector piece x then _iAll satisfy following formula: x ' _i=RM * u ' _iIn the formula, for N dimension rotation modulation, N is the natural number greater than 1, u _iBe the row vector of N dimension, the modulation symbol before the expression rotation modulation treatment, u ' _iBe u _iThe transposition column vector; x _iBe the row vector of N dimension, the modulation symbol after the expression multidimensional rotation modulation, x ' _iBe x _iThe transposition column vector; RM is the spin matrix on N rank, and the quadratic sum of its every row or every row all is 1, satisfies orthogonality between row vector or the column vector;

(15) will finish the symbolic vector piece x of rotation after the modulation treatment and deposit memory in.

3, method according to claim 2, it is characterized in that: the dimension that the symbolic vector piece of described employing spin matrix RM after to modulation carries out multidimensional rotation modulation comprises 2 dimensions, 4 dimensions, 8 dimension or higher dimensions, but, the calculation of complex of the rotation modulation of 8 dimensions or higher dimension, and advantage is not obvious; So what selection was maximum is 2 peacekeepings, 4 dimensions; Its concrete grammar is;

When selecting two dimension rotation modulation, each two-dimensional modulation symbolic vector is that in-phase component and the quadrature component by a modulation symbol constituted, and promptly rotates the in-phase component and the quadrature component of a modulation symbol vector of modulation treatment at every turn; Therefore, establishing each preceding modulation symbol vector of two dimension rotation modulation treatment is u _i=A+Bj, wherein, A is u _iIn-phase component, B is u _iQuadrature component; Spin matrix $\mathrm{RM}=\left(\begin{array}{cc}\cos \mathrm{\&theta;}& \sin \mathrm{\&theta;}\\ -\sin \mathrm{\&theta;}& \cos \mathrm{\&theta;}\end{array}\right),$ θ is the anglec of rotation of setting, and its span is Through the symbolic vector after the two dimension rotation modulation treatment is x _iDuring=X+Yj, then $\left(\begin{array}{c}X\\ Y\end{array}\right)=\mathrm{RM}\&times;\left(\begin{array}{c}A\\ B\end{array}\right),$ Promptly $\left(\begin{array}{c}X\\ Y\end{array}\right)=\left(\begin{array}{cc}\cos \mathrm{\&theta;}& \sin \mathrm{\&theta;}\\ -\sin \mathrm{\&theta;}& \cos \mathrm{\&theta;}\end{array}\right)\left(\begin{array}{c}A\\ B\end{array}\right),$

When selecting four-dimensional rotation modulation, each four-dimensional modulation symbol is that in-phase component and the quadrature component by two adjacent modulation symbol vectors constituted, and promptly rotates two adjacent modulation symbol vectors of modulation treatment in-phase component and quadrature component separately at every turn; So two modulation symbol vectors establishing before the four-dimensional rotation modulation treatment are respectively A+Bj and C+Dj, when the value of these two the modulation symbol vector correspondences after the four-dimensional rotation modulation of process is respectively X+Yj and Z+Wj, then $\left(\begin{array}{c}X\\ Y\\ Z\\ W\end{array}\right)=\mathrm{RM}\&times;\left(\begin{array}{c}A\\ B\\ C\\ D\end{array}\right),$ In the formula,

$\mathrm{RM}=\left(\begin{array}{cccc}\cos {\mathrm{\&theta;}}_1\cos {\mathrm{\&theta;}}_2& \sin {\mathrm{\&theta;}}_1\cos {\mathrm{\&theta;}}_2& \cos {\mathrm{\&theta;}}_1\sin {\mathrm{\&theta;}}_1& \sin {\mathrm{\&theta;}}_1\sin {\mathrm{\&theta;}}_2\\ -\sin {\mathrm{\&theta;}}_1\cos {\mathrm{\&theta;}}_2& \cos {\mathrm{\&theta;}}_1\cos {\mathrm{\&theta;}}_2& -\sin {\mathrm{\&theta;}}_1\sin {\mathrm{\&theta;}}_2& \cos {\mathrm{\&theta;}}_1\sin {\mathrm{\&theta;}}_2\\ -\cos {\mathrm{\&theta;}}_1\sin {\mathrm{\&theta;}}_2& -\sin {\mathrm{\&theta;}}_1\sin {\mathrm{\&theta;}}_1& \cos {\mathrm{\&theta;}}_1\cos {\mathrm{\&theta;}}_2& \sin {\mathrm{\&theta;}}_1\cos {\mathrm{\&theta;}}_2\\ \sin {\mathrm{\&theta;}}_1\sin {\mathrm{\&theta;}}_2& -\cos {\mathrm{\&theta;}}_1\sin {\mathrm{\&theta;}}_2& -\sin {\mathrm{\&theta;}}_1\cos {\mathrm{\&theta;}}_2& \cos {\mathrm{\&theta;}}_1\cos {\mathrm{\&theta;}}_2\end{array}\right),$ θ ₁And θ ₂Be respectively the anglec of rotation of setting, its span is

4, method according to claim 1 is characterized in that: described step (2) further comprises following content of operation:

(21) transmitting terminal is to all users' symbolic vector piece x, according to the centralized or distributed OFDM mode assignments OFDM running time-frequency resource of setting, wherein, time resource is the time slot that the OFDM symbol sends successively, and frequency resource is to send the shared subcarrier bandwidth of each OFDM symbol; Just the quantity L of each included user modulation symbol is set in each OFDM symbol: $L=\frac{\mathrm{OFDM}\_\mathrm{Length}}{P}=\frac{S}{\mathrm{OFDM}\_\mathrm{Num}};$ In the formula, OFDM_Length is the number of modulation symbols in each OFDM symbol, and P is all users' a sum, and S is the modulation symbol number that at every turn transmits transmission each user, and OFDM_Num is the OFDM symbolic number that sends in each OFDM transmission course; Thereby make each OFDM symbol comprise L * P modulation symbol, it occupies OFDM_Length subcarrier bandwidth on frequency domain; And always total OFDM_Num OFDM symbol occupies OFDM_Num time slot on time domain;

(22) according to the dimension of the selected multidimensional of abovementioned steps rotation modulation, the symbolic vector piece of each user in the OFDM symbol is carried out following corresponding Q road interleaving treatment: the time-frequency of modulation symbol vector interweaves, Q road frequency-domain-interleaving and Q road time-frequency two-dimensional interleaver interweave.

5, method according to claim 4, it is characterized in that: when transmitting terminal carries out the Q road when interweaving according to centralized OFDM pattern, if adopt two dimension rotation modulation, in the then described step (22), the time-frequency of not carrying out the modulation symbol vector interweaves and the operation of Q road frequency-domain-interleaving, directly carries out the interlace operation of Q road time-frequency two-dimensional interleaver; If adopt the rotation modulation of four-dimensional or higher dimension, then described step (22) comprises following content of operation:

(221) symbolic vector of transmitting terminal after to the rotation of same user in each OFDM symbol period modulation carried out the time-frequency interleaving treatment, and the time-frequency interlacing rule is: the symbolic vector after each user's the rotation modulation is stored in according to writing mode line by line

Behind the interleaver of form, again according to taking out by the row mode, with the conversion that interweaves of the time-frequency by this symbolic vector, reduce in each rotation modulation the time domain between two adjacent-symbol vectors and the correlation of frequency domain, in the formula, D is the dimension of multidimensional rotation modulation;

(222) the Q road quadrature component of the symbolic vector after the time-frequency of each user in each OFDM symbol period is interweaved is carried out frequency-domain-interleaving in regular turn and is handled, and the frequency-domain-interleaving rule is that the modulation symbol vector of the L that belongs to same user in each OFDM symbol is handled together: earlier with in this L symbolic vector, be spaced apart The Q road component of D symbolic vector be made as one group, total

Group; Again the circulation to the right in regular turn of the Q road component in every group is moved one, i.e. Q _fMove to

The position, and

Move to

The position, Then move to The position, correspondingly, last Q road component then moves to Q _fThe position; And then with the new symbolic vector of Q road quadrature component merging composition after I road in-phase component and the displacement;

(223) according to the time-frequency two-dimensional interlacing rule of setting, each user is evenly distributed in whole S modulation symbols that in each OFDM symbol, at every turn send carries out interleaving treatment, make quadrature component and its in-phase component of any one modulation symbol in each this S modulation symbol that sends of each user after interweaving all uncorrelated mutually as much as possible on time and frequency, even the distance of quadrature component and its in-phase component is far away as far as possible;

When transmitting terminal carries out the Q road when interweaving according to distributed OFDM pattern, after first operation rules according to above-mentioned centralized OFDM pattern calculates step (22) result, again centralized result of calculation distributed frequency point allocation mode according to step (21) on frequency domain is come the even expansion of result, the invariant position of time domain, and, the relative position of frequency domain is also constant, has just changed the absolute position of subcarrier frequency.

6, method according to claim 5 is characterized in that: described time-frequency two-dimensional interlacing rule is: will this same user, the modulation symbol of W subcarrier bandwidth is made as one group at interval on frequency domain, supposes that again choosing two sequence numbers is f ₁, f ₂Subcarrier, wherein, f ₂=f ₁+ W, W are two sub-carrier frequency point f ₁And f ₂Bandwidth granularity; $W=\frac{L}{2},$ And the position coordinates of establishing the Q road component of each modulation symbol is (f, t), represent that f modulation symbol in each OFDM symbol is positioned at f sub-carrier frequency point on the frequency domain and t OFDM symbol on the time domain, natural number t is the sequence number of OFDM symbol, and its maximum is OFDM_Num; The Q road component of order choice of modulation symbol is promptly chosen f in the 1st the OFDM symbol earlier earlier ₁The Q road component of individual modulation symbol is chosen at interval on the time domain again Of individual OFDM symbol

F in the individual OFDM symbol ₂The Q road component of individual modulation symbol; Then choose f in the 2nd the OFDM symbol ₁The Q road component of individual modulation symbol is chosen at again

F in the individual OFDM symbol ₂The Q road component of individual modulation symbol continues to choose f in the 3rd the OFDM symbol ₁The Q road component of individual modulation symbol chooses again

F in the individual OFDM symbol ₂The Q road component of individual modulation symbol, and the like, according on time domain,, select again to be separated by with it from the 1st OFDM symbol choosing

Of individual OFDM symbol Individual OFDM symbol, and then increase the 2nd OFDM symbol of a selection, select again to be separated by with it Of individual OFDM symbol

Individual OFDM symbol, and the like, choose from always

Individual OFDM symbol is selected to be separated by with it again (OFDM_Num) individual OFDM symbol of individual OFDM symbol on frequency domain, is exactly f ₁, f ₂Alternate selection; Like this, before interweaving, the position coordinates of the Q road component of each modulation symbol in each OFDM symbol is respectively:

$\{(f_1,1)(f_2,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}+1),(f_1,2),(f_2,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}+2),\&CenterDot;\&CenterDot;\&CenterDot;,(f_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}),(f_2,\mathrm{OFDM}\_\mathrm{Num})\},$ After the time-frequency two-dimensional of process Q road component interweaved, the frequency domain that it is occupied and the position coordinates of time domain were that one result is moved in the Q road component circulation to the right in regular turn of original OFDM symbol just, are $\{(f_2,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}+1),(f_1,2),(f_2,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}+2),\&CenterDot;\&CenterDot;\&CenterDot;,(f_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}),(f_2,\mathrm{OFDM}\_\mathrm{Num}),(f_1,1)\};$ Therefore, the I road component after the process time-frequency two-dimensional interweaves and the time interval minimum of Q road component are

The time length of field OFDM_Num * T that is about the OFDM symbol _sHalf, wherein, T _sIt is the transmission time of OFDM symbol; Frequency domain interval be corresponding ofdm system frequency domain length 1/2nd; Thereby make the low time-frequency two-dimensional of computation complexity interweave and fully to effectively utilize the frequency diversity and the time diversity of ofdm system, and realize combined optimization with modulation diversity.

7, method according to claim 1 is characterized in that, described step (3) further comprises following content of operation:

(31) respectively to not enough IFFT computing length in each OFDM symbol the position long zero padding after, again each OFDM symbol is carried out the IFFT computing respectively according to the following equation: $x\left(n\right)=\frac{1}{\sqrt{N}}\underset{k=0}{\overset{N-1}{\mathrm{\&Sigma;}}}X\left(k\right)e^{j\frac{2\mathrm{\&pi;}}{N}\mathrm{kn}},$ In the formula, N is a sub-carrier number, and X (k) is the complex signal of setting under the modulating mode, and x (n) is the sampling of OFDM symbol in time domain, and the definition of the j of imaginary unit is: j ²=-1, k is the sequence number of the symbolic vector in the OFDM symbol, and its span is the nonnegative integer of [0, N-1];

(32) the OFDM symbol after each process IFFT computing is added cyclic prefix CP respectively, eliminate the intersymbol interference that the multipath channel transmission causes; The concrete operations content is: μ symbol of each OFDM symbol afterbody copied the front end that is added into this OFDM symbol, and wherein, μ is the length of CP;

(33) send each OFDM symbol successively.

8, method according to claim 1 is characterized in that, described step (4) further comprises following content of operation:

(41) after receiving terminal received data, it is separated OFDM handle: earlier each the OFDM symbol that receives is removed CP respectively, each the OFDM symbol that is about to receive was deleted μ symbol of its head respectively; Again each OFDM symbol is carried out fast Fourier transform FFT computing respectively according to the following equation: $X\left(k\right)=\frac{1}{\sqrt{N}}\underset{k=0}{\overset{N-1}{\mathrm{\&Sigma;}}}x\left(n\right)e^{-j\frac{2\mathrm{\&pi;}}{N}\mathrm{kn}},$ In the formula, N is a sub-carrier number, and X (k) is the complex signal of setting under the modulating mode, and x (n) is the sampling of OFDM symbol in time domain, and the definition of the j of imaginary unit is: j ²=-1, k is the sequence number of the symbolic vector in the OFDM symbol, and its span is the nonnegative integer of [0, N-1]; Then, the OFDM symbol after the conversion is stored;

(42) the OFDM symbol after the conversion is carried out phase compensation, so that eliminate the influence of multipath transmission to data according to channel estimation value; The phase compensation formula is: $y\left(t\right)=\frac{x\left(t\right)\&times;\stackrel{\&OverBar;}{h\left(t\right)}}{\left|h\left(t\right)\right|};$ In the formula, x (t) is the symbolic vector in each OFDM symbol, h (t), h (t) and | h (t) | be respectively channel guess value, the conjugation of channel guess value and mould;

(43) each the OFDM symbol after the phase compensation is removed zero, promptly delete position long add zero of step (31), then, each OFDM symbol is stored for coupling IFFT computing length;

(44) the centralized or distributed OFDM pattern of selecting according to step (13) that the multidimensional rotation is modulated and step (21) is selected, symbolic vector in each OFDM symbol is carried out the deinterleaving of corresponding Q road handle, promptly carry out reverse process according to the rule of correspondence of step (22).

(45) proceed OFDM and separate time-frequency resource allocating operation: with this step (21) be distributed in whole OFDM symbols on the OFDM running time-frequency resource all L * P modulation symbol according to the contrary operation of this step in proper order, be reduced to all users' of serial symbolic vector again;

(46) adopt the maximum likelihood demodulation mode that the symbolic vector that OFDM separates after the time-frequency resource allocating is rotated demodulation: being demodulation reference constellation figure through the rotation planisphere after the multipath channel, the Euclidean distance of each constellation point among each symbolic vector in the symbolic vector set that calculating receives and its reference constellation figure, obtain shining upon the log-likelihood ratio of each bit that becomes each symbolic vector respectively, be used for decoding;

(47) according to the corresponding decoded mode of coding mode selection, every group of OFDM symbol substitution is reduced to K the information bit that the position is long, all flow process finishes.

9, method according to claim 7, it is characterized in that: when receiving terminal carries out the deinterleaving of Q road according to centralized OFDM pattern, if adopt two dimension rotation modulation, in the then described step (44), only carry out the deinterleaving operation of Q road time-frequency two-dimensional interleaver, do not carry out the time-frequency deinterleaving of modulation symbol vector and the operation of Q road frequency domain deinterleaving; If adopt the rotation modulation of four-dimensional or higher dimension, then described step (44) comprises following content of operation:

(441) according to the reverse process method of the time-frequency two-dimensional interlacing rule of step (223) the Q road component of symbolic vector is carried out deinterleaving: the Q road component of order choice of modulation symbol earlier, promptly choose the earlier

F in the individual OFDM symbol ₂The Q road component of individual modulation symbol is chosen f in the 2nd the OFDM symbol again ₁The Q road component of individual modulation symbol then chooses

F in the individual OFDM symbol ₂The Q road component of individual modulation symbol is chosen f in the 3rd the OFDM symbol again ₁The Q road component of individual modulation symbol continues to choose

F in the individual OFDM symbol ₂The Q road component of individual modulation symbol is chosen f in the 3rd the OFDM symbol then ₁The Q road component of individual modulation symbol, and the like; On time domain according to from

Individual OFDM symbol selects, and selects the 2nd OFDM symbol again, then selects to be separated by with it

Individual OFDM symbol Individual OFDM symbol is selected from the 3rd OFDM symbol of 1 OFDM symbol of the 2nd increase again, selects then to be separated by with it

Individual OFDM symbol

Individual OFDM symbol, and the like, choose from

Individual OFDM symbol is selected to be separated by with it again

(OFDM_Num) individual OFDM symbol of individual OFDM symbol is chosen the 1st OFDM symbol at last; On frequency domain f ₂, f ₁Alternate selection; Like this, before interweaving, the position coordinates of the Q road component of each modulation symbol in each OFDM symbol is respectively:

$\{(f_2,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}+1),(f_1,2),(f_2,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}+2),\&CenterDot;\&CenterDot;\&CenterDot;,(f_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}),(f_2,\mathrm{OFDM}\_\mathrm{Num}),(f_1,1)\},$ After the time-frequency two-dimensional deinterleaving through Q road component, the frequency domain that it is occupied and the position coordinates of time domain are that one result is moved in the Q road component circulation left in regular turn of original OFDM symbol just, are:

$\{(f_1,1)(f_2,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}+1),(f_1,2),(f_2,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}+2),\&CenterDot;\&CenterDot;\&CenterDot;,(f_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}),(f_2,\mathrm{OFDM}\_\mathrm{Num})\},$ Make Q road quadrature component symbol on time and frequency, all carry out place-exchange: (f according to above-mentioned rule ₁, 1) → (f ₂, OFDM_Num), $(f_2,\mathrm{OFDM}\_\mathrm{Num})\&RightArrow;(f_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}),$ $(f_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2})\&RightArrow;(f_2,\mathrm{OFDM}\_\mathrm{Num}-1),$ $(f_2,\mathrm{OFDM}\_\mathrm{Num}-1)\&RightArrow;(f_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}-1),$ $(f_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}-1)\&RightArrow;(f_2,\mathrm{OFDM}\_\mathrm{Num}-2),$ ......，(f ₂，OFDM_Num/2+2)→(f ₁，2)，(f ₁，2)→(f ₂，OFDM_Num/2+1)，(f ₂，OFDM_Num/2+1)→(f ₁，1)；

(442) according to the reverse process method of step (222) the Q road component of symbolic vector is separated frequency-domain-interleaving, its rule is: in same user's L the symbolic vector, be spaced apart in each OFDM symbol The Q road component of D symbolic vector be made as one group, the Q road component in this group circulation is left successively moved one, the imaginary part and the real part that then will belong to the prosign vector originally mate reduction;

(443) according to the reverse process method of step (221) symbolic vector is carried out the time-frequency deinterleaving, its rule is: to each user's symbolic vector according to be stored in by the row writing mode with

Behind the interleaver of form, take out according to row-by-row system again, finish the time-frequency deinterleaving conversion of symbolic vector;

When receiving terminal carries out the deinterleaving of Q road according to distributed OFDM pattern, then earlier according to centralized frequency point allocation mode with distributed reduction become centralized after, carry out above-mentioned steps (44) corresponding operating again.

10, method according to claim 1, it is characterized in that: in the planisphere of described step (46), every kind of a plurality of bits combination becomes certain of rotating in the planisphere and puts a corresponding symbol, according to i position bit in these bit combinations is 0 or 1, and planisphere is divided into two set: set of 0 constellation point and the set of 1 constellation point; At this moment, judge that the computing formula that i position bit in the pairing a plurality of bits of each symbol is respectively 0 and 1 probability is respectively:

With

In the formula, { d _I0Be that this symbol that receives is gathered { d with the distance that is 0 all constellation point of dividing according to i position bit _I1Being this symbol that receives and the distance set that according to i position bit is 1 all constellation point of dividing, natural number i is a bit sequence in the bit combination; Calculate the log-likelihood ratio of pairing each bit of each symbol thus respectively: In the formula, b _vBe v bit in certain symbol that is mapped to by a plurality of bits after the modulation; P (b _v=0|r) be the symbol that receives when being r, judge bit b _vBe 0 probability, P (b _v=1|r) be the symbol that receives when being r, judge bit b _vIt is 1 probability.

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