CN101621490B - 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 of the modulation diversity joint codes for ofdm system

Technical field

The present invention relates to a kind of method of the modulation diversity joint codes for ofdm system, exactly, relate to a kind of method that in ofdm system, signal synthesis is adopted multidimensional rotation modulation, chnnel coding and diversity, in order to can fully utilize well the gain of time diversity, frequency diversity, modulation diversity and chnnel coding under the fading channel, 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 consider and design, so that the coded signal sequence that produces after encoder and the modulator cascade has 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 Channels: this moment, its performance became very poor.So the coded modulation scheme how searching is best in fading channel just becomes study hotspot 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 increase diversity number and increases long-pending distance that this is so that TCM coding method nonexistence energy 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.The people such as 1996 Nainas, G Caire have calculated the capacity of BICM scheme in 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 the data flow that is converted to one group of low-speed parallel transmission by the data flow with high-speed transfer, so that system reduces greatly for the susceptibility degree of multidiameter fading channel frequency selectivity, thereby have the ability that good antinoise and anti-multipath disturb, be applicable 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.In optimally diversified situation, error probability can be along with the increase of average signal-to-noise ratio index decreased.In the BICM algorithm, although the Bit Interleave technology has increased code modulated time diversity degree; But, because the reducing of minimum Eustachian distance, make again the deterioration that becomes of the transmission performance of this technical scheme under Gaussian channel.Therefore, how to solve this technical barrier, become the in the industry focus of scientific and technical personnel's concern.

Summary of the invention

In view of this, the method that the purpose of this invention is to provide a kind of modulation diversity joint codes for ofdm system, the anglec of rotation and the component of the 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 again the optimum anglec of rotation, 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 of the modulation diversity joint codes for 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 I road in-phase component and the Q road quadrature component of the symbolic vector piece of all users after modulating are carried out the multidimensional rotation modulation again, then the symbolic vector piece behind 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, again the symbolic vector piece of each user in the OFDM symbol is carried out Q road interleaving treatment;

(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, then send data;

(4) behind the receiving terminal receive data, first this data block symbols is removed the solution OFDM processing of CP and fast Fourier transform FFT computing, carry out again phase compensation and zero-suppress, then the OFDM symbol that obtains is carried out the deinterleaving of Q road, OFDM solution time-frequency resource allocating, rotation solution mediation decoding successively, obtain required data message.

The present invention is a kind of method of the modulation diversity joint codes for 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 method of signal diversifying of ofdm system ".Application for a patent for invention in 2008 is to obtain diversity technique to lifting and the improvement of transmission performance by the Two Dimensional Rotating modulation, the present invention expands to the multidimensional rotation modulation with this patented technology, can utilize better modulation diversity, 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 technology of adopting, introduce the signal diversifying gain at the rotation modulation planisphere, so that the in-phase component (I road) that the modulation symbol after sending produces in transmission course and quadrature component (Q road) are independently transmitted 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, obtain the maximum lift on the performance.In addition, also introduce OFDM frequency diversity and the diversity that interweaves, in the transmission of fading channel, properties that can the Effective Raise communication system obtains 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, successful, applicable to the Multi-encoding 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 popularizing 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), (b) are respectively interweave the time-frequency interlacing rule schematic diagram of middle modulation symbol and Q road frequency-domain-interleaving rule schematic diagrames of four-dimensional rotation modulation Q road.

Fig. 3 (a), (b) are respectively 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), (b) are respectively centralized and distributed two kinds of pattern diagram in the OFDM frame structure.

Fig. 6 is 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), (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 present invention for the concrete operation step of the method for the modulation diversity joint codes of ofdm system, it is to adopt OFDM technology and multidimensional rotation modulation technology, interweaves by the component that rotates planisphere, modulation symbol, 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 I road in-phase component and the Q road quadrature component of the symbolic vector piece of all users after modulating are carried out the multidimensional rotation modulation again, then the symbolic vector piece behind the rotation modulation is stored.This step 1 comprises following concrete operations content:

(11) transmitting terminal calculates first the total G:G=OFDM_Num * OFDM_Length of the modulation symbol that all users send in each transmission course, 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 again the modulation symbol of each user's transmission 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 formed by m bit mapping, be i.e. M=2 ^m, m=log then ₂M, the code length N:N=S of the transmission data of calculating each user behind coding * m; The information bit position long K:K=r * N of the transmission data of calculating again each user before coding, in the formula, code check r be span be (0,1] real number;

In an embodiment, modulation system is selected respectively QPSK, 16QAM and 64QAM, therefore order of modulation is respectively 4,16 and 64, the information bit that each modulation symbol is corresponding is respectively 2,4 and 6, thereby the code length N that calculates behind each user's the transmission data encoding 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 information bit bit length K must meet the information bit bit length of the Turbo coding of agreement 3GPP TS 36.212 regulations.Information bit bit length K for above-mentioned employing, if do not satisfy the information bit bit length of the Turbo coding of agreement 3GPP TS 36.212 regulations, just select immediate information bit bit length in the agreement, afterbody in these data replenishes zero again, reaches above-mentioned information bit bit length K requirement of calculating.

The K bit information that (13) 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 corresponding sign map 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 form 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) the symbolic vector piece after adopting spin matrix RM to modulation carries out the multidimensional rotation modulation, obtains the modulation diversity gain: the symbolic vector piece x that establishes behind the rotation modulation 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 _iThe row vector of N dimension, the modulation symbol before the expression rotation modulation is processed, u _i' be u _iThe transposition column vector; x _iThe row vector of N dimension, the modulation symbol behind 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 the 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 selecting maximum is 2 peacekeepings, 4 dimensions; Its concrete grammar is;

When selecting the Two Dimensional Rotating modulation, each two-dimensional modulation symbolic vector is that in-phase component and the quadrature component by a modulation symbol consisted of, i.e. in-phase component and the quadrature component of a modulation symbol vector of each rotation modulation processing; Therefore, establishing each front modulation symbol vector of Two Dimensional Rotating 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 Symbolic vector after the process Two Dimensional Rotating modulation treatment is x _iDuring=X+Yj, then $\left(\begin{array}{c}X\\ Y\end{array}\right)=\mathrm{RM}\×\left(\begin{array}{c}A\\ B\end{array}\right),$ Namely $\left(\begin{array}{c}X\\ Y\end{array}\right)=\left(\begin{array}{cc}\cos \mathrm{\θ}& \sin \mathrm{\θ}\\ -\sin \mathrm{\θ}& \cos \mathrm{\θ}\end{array}\right)\left(\begin{array}{c}A\\ B\end{array}\right);$

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 consisted of, and namely each rotation modulation is processed two adjacent modulation symbol vectors in-phase component and quadrature component separately; So two modulation symbol vectors establishing before four-dimensional rotation modulation is processed are respectively A+Bj and C+Dj, when being respectively X+Yj and Z+Wj through these two values corresponding to modulation symbol vector behind the four-dimensional rotation modulation, 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 to be 1 symbolic vector with per 2 bit mappings, have 4 kinds of possible bit combinations and corresponding symbolic 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 forms behind Fig. 3 (a) process θ degree rotation modulation, wherein X, Y are respectively the projection of each constellation point on real part axle and imaginary part axle behind the rotation modulation, after the rotation modulation computing, 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 behind 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 behind the rotation modulation 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:

The symbolic vector piece x that (15) will finish after rotation modulation is processed deposits 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, again the symbolic vector piece of each user in the OFDM symbol is carried out Q road interleaving treatment.

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; Namely 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' 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 so that each OFDM symbol comprises L * P modulation symbol, it occupies OFDM_Length subcarrier at frequency domain; Total OFDM_Num OFDM symbol occupies OFDM_Num time slot in 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 namely each OFDM symbol 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 represents 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 with per 5 groups of same user's symbolic vector piece successively, has 2 * N _SymbRow, namely 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.First by above-mentioned same method with user's symbolic vector piece take 12 modulation symbols as one group divide into groups after, successively that 60 grouping block of each user are arranged sequentially by row, each user's symbolic vector blocking is 1 * 60 matrix, then 20 users' symbolic vector piece has formed 20 * 60 matrix, according to shown in the arrow, column major order takes out again.After namely successively first group of each user being taken out, continue again to get each user second group, by that analogy, until take the 60th group of 20 users.

(22) according to the dimension of the selected multidimensional rotation modulation of abovementioned steps, 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 the Two Dimensional Rotating modulation, then in the 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 modulation of same user in each OFDM symbol period carried out the time-frequency interleaving treatment, and the time-frequency interlacing rule is: the symbolic vector behind each user's the rotation modulation is stored in according to writing mode line by line

Behind the interleaver of form, take out according to mode by column again, with the conversion that interweaves of the time-frequency by this symbolic vector, reduce in each rotation modulation 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 the Two Dimensional Rotating modulation, execution in step (221) not then; If adopt four-dimensional rotation modulation, the time-frequency that then carries out modulation symbol according to step (221) interweaves, and once simultaneously treated two symbols of four-dimensional rotation modulation disperse to be placed on to be separated by

Two frequencies on the interval of 30 symbols so that these two symbols are separated by, thus reduce once four-dimensional rotation modulation process in 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 sequentially carried out frequency-domain-interleaving and is processed, 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 processed together: first 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 with the Q road component in every group sequentially to the right one of loopy moving, 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, namely: 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 the Two Dimensional Rotating 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 that is spaced apart four modulation symbols of 15 symbols is divided to measure 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 operation 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 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 in a location interval OFDM_Num time slot in time domain, be between two frequencies of interval OFDM_Num OFDM symbol distance farthest, correlation is the most weak; Be in a location interval L subcarrier bandwidth at frequency domain, be between two signaling points of an interval L symbol distance farthest, correlation is the most weak, still, in order to guarantee equably substep of all frequencies, selects to satisfy 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 an interval W subcarrier bandwidth is made as one group on frequency domain, to choose two sequence numbers be f to hypothesis again ₁, f ₂Subcarrier, wherein, f ₂=f ₁+ W, W are two sub-carrier frequency point f ₁And f ₂Bandwidth granularity; $W=\frac{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">L</figure-callout>}}{2},$ 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 namely chosen first f in the 1st the OFDM symbol first 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, the like, according on time domain, from the 1st OFDM symbol choosing, select again to be separated by with it

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, 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:

$\{({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,1),({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\frac{\mathrm{OFDM}\_\mathrm{<figure-callout\; id="2"\; label="Num"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">Num</figure-callout>}}{2}+1),({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,2),({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\frac{\mathrm{OFDM}\_\mathrm{<figure-callout\; id="2"\; label="Num"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">Num</figure-callout>}}{2}+2),\&CenterDot;\&CenterDot;\&CenterDot;,({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}),({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\mathrm{OFDM}\_\mathrm{Num})\},$ After interweaving through the time-frequency two-dimensional of Q road component, the position coordinates of the frequency-domain and time-domain that it is occupied is the Q road component result of one of loopy moving to the right sequentially of original OFDM symbol just, is $\{({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\frac{\mathrm{OFDM}\_\mathrm{<figure-callout\; id="2"\; label="Num"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">Num</figure-callout>}}{2}+1),({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,2),({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\frac{\mathrm{OFDM}\_\mathrm{<figure-callout\; id="2"\; label="Num"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">Num</figure-callout>}}{2}+2),\&CenterDot;\&CenterDot;\&CenterDot;,({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}),({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\mathrm{OFDM}\_\mathrm{Num}),({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,1)\};$ 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 can fully effectively utilize frequency diversity and the time diversity of ofdm system so that the low time-frequency two-dimensional of computation complexity interweaves, 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, namely 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 an OFDM symbol on 30 subcarrier bandwidth in interval on the frequency domain and the time 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) to represent that the Q road component of this modulation symbol occupies f subcarrier at frequency domain, occupies t OFDM symbol in 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, then send data.

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 respectively the IFFT computing according to the following equation: $x\left(n\right)=\frac{1}{\sqrt{N}}\underset{k=0}{\overset{N-1}{\mathrm{\&Sigma;}}}X\left(k\right){\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">e</figure-callout>}}^j,$ In the formula, N is sub-carrier number, and X (k) is the complex signal of setting under the modulating mode, x (n) be the OFDM symbol in the sampling of time domain, 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 represents the distribution condition of OFDM symbol on subcarrier bandwidth, and the longitudinal axis represents the distribution condition of OFDM symbol on time slot.Be 1200 according to each OFDM symbol lengths shown in Figure 4, each OFDM transmission course is processed 12 OFDM symbols, takies 2048 OFDM subcarrier bandwidth; The 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 respectively CP, eliminate the intersymbol interference that multi-path 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 processes increases to 2560.

(33) send successively each OFDM symbol.

Behind step 4, the receiving terminal receive data, first this data block symbols is removed the solution OFDM processing of CP and fast Fourier transform FFT computing, carry out again phase compensation and zero-suppress, then the OFDM symbol that obtains is carried out the deinterleaving of Q road, OFDM solution time-frequency resource allocating, rotation solution mediation decoding successively, obtain required data message.This step 4 comprises following concrete operations content:

(41) behind the receiving terminal receive data, it is separated OFDM process: first each the OFDM symbol that receives is removed respectively CP, each the OFDM symbol that is about to receive is deleted respectively μ symbol of its head; Again each OFDM symbol is carried out respectively fast Fourier transform FFT computing according to the following equation: $X\left(k\right)=\frac{1}{\sqrt{N}}\underset{k=0}{\overset{N-1}{\mathrm{\&Sigma;}}}x\left(n\right)e^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;}}{N}\mathrm{kn}},$ In the formula, N is sub-carrier number, and X (k) is the complex signal of setting under the modulating mode, x (n) be the OFDM symbol in the sampling of time domain, 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, in order to eliminate Multipath Transmission to the impact of 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, namely delete step (31) then, is stored each OFDM symbol for long add zero in position of 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 multidimensional rotation modulation and the step (21) of step (13) selection, symbolic vector in each OFDM symbol is carried out the deinterleaving of corresponding Q road process, namely 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 the Two Dimensional Rotating modulation, then in the 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 that Q road Frequency Domain Solution interweaves; 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 first Q road component of order choice of modulation symbol, namely choose first the

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 ₂Then the Q road component of individual modulation symbol chooses f in the 3rd the OFDM symbol ₁The Q road component of individual modulation symbol, 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, then selects to be separated by with it

Individual OFDM symbol

Individual OFDM symbol, 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; F at frequency domain 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:

$\{({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\frac{\mathrm{OFDM}\_\mathrm{<figure-callout\; id="2"\; label="Num"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">Num</figure-callout>}}{2}+1),({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,2),({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\frac{\mathrm{OFDM}\_\mathrm{<figure-callout\; id="2"\; label="Num"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">Num</figure-callout>}}{2}+2),\&CenterDot;\&CenterDot;\&CenterDot;,({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}),({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\mathrm{OFDM}\_\mathrm{Num}),({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,1)\},$

After the time-frequency two-dimensional deinterleaving through Q road component, the position coordinates of the frequency-domain and time-domain that it is occupied is the Q road component result of one of loopy moving left sequentially of original OFDM symbol just, is:

$\{({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,1),({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\frac{\mathrm{OFDM}\_\mathrm{<figure-callout\; id="2"\; label="Num"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">Num</figure-callout>}}{2}+1),({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,2),({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\frac{\mathrm{OFDM}\_\mathrm{<figure-callout\; id="2"\; label="Num"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">Num</figure-callout>}}{2}+2),\&CenterDot;\&CenterDot;\&CenterDot;,({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}),({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\mathrm{OFDM}\_\mathrm{Num})\}$

So that Q road quadrature component symbol all carries out place-exchange according to above-mentioned rule on time and frequency

$({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,1)\&RightArrow;({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\mathrm{OFDM}\_\mathrm{Num}),({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\mathrm{OFDM}\_\mathrm{Num})\&RightArrow;({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}),$

$({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2})\&RightArrow;({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\mathrm{OFDM}\_\mathrm{Num}-1),({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\mathrm{OFDM}\_\mathrm{Num}-1)\&RightArrow;({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}-1),$

$({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}-1)\&RightArrow;({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\mathrm{OFDM}\_\mathrm{Num}-2),......,({\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_2,\mathrm{OFDM}\_\mathrm{Num}/2+2)\&RightArrow;({\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">f</figure-callout>}}_1,2),$

(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 originally belonging to same modulation symbol mates reduction, and concrete grammar is: interval on 30 subcarrier bandwidth in interval on the frequency domain and the time domain is got more than or equal to the frequency of 5 OFDM symbols 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 occupy f subcarrier at frequency domain, occupy t OFDM symbol in 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, with the Q road component in this group successively one of loopy moving left, imaginary part and the real part that then will originally belong to the prosign vector mate reduction.

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

(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 writing mode by column be stored in

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 the Two Dimensional Rotating modulation, do not carry out this step (453), if adopt four-dimensional rotation modulation, the concrete grammar that then interweaves according to this step (453) solution time-frequency 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 adjacent position, thus the position of four components of reduction before once four-dimensional rotation modulation is processed.

(45) proceed OFDM and separate the 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 sequentially, again be reduced to all users' of serial symbolic vector.

(46) adopt the maximum-likelihood demodulation mode that the symbolic vector that OFDM separates after the time-frequency resource allocating is rotated demodulation: take through the rotation planisphere after the multipath channel as demodulation reference constellation figure, 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 respectively shining upon the log-likelihood ratio of each bit that becomes each symbolic vector, be used for decoding.

Referring to Fig. 8, introduce and use planisphere and the demodulation mode thereof of rotation modulation planisphere through forming after the fading channel.The signal on I road and Q road has respectively different channel fading amplitude distortions 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 acceptance point to the distance of each constellation point, i.e. d shown in the figure ₁～d ₄, calculate again the log-likelihood ratio of every bit corresponding to this symbol.Take first bit as example, 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:

$\log \frac{\exp (-\frac{{{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">d</figure-callout>}}_1}^2}{2{\mathrm{\&sigma;}}^2})+\exp (-\frac{{{\mathrm{<figure-callout\; id="4"\; label="d"\; filenames="H2009100911634E00012.png,H2009100911634E00042.png"\; state="\{\{state\}\}">d</figure-callout>}}_4}^2}{2{\mathrm{\&sigma;}}^2})}{\exp (-\frac{{{\mathrm{<figure-callout\; id="3"\; label="d"\; filenames="H2009100911634E00042.png,H2009100911634E00051.png"\; state="\{\{state\}\}">d</figure-callout>}}_3}^2}{2{\mathrm{\&sigma;}}^2})+\exp (-\frac{{{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="H2009100911634E00011.png,H2009100911634E00012.png"\; state="\{\{state\}\}">d</figure-callout>}}_2}^2}{2{\mathrm{\&sigma;}}^2})}.$

(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.The parameters of this embodiment is described 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 that 2048, 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), (b) be respectively the embodiment of the invention and at present Bit Interleave coded modulation BICMOFDM mode 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 successfully, has realized goal of the invention.

Claims (8)

1. 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 I road in-phase component and the Q road quadrature component of the symbolic vector piece of all users after modulating are carried out four-dimensional rotation modulation again, then the symbolic vector piece behind 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, again the symbolic vector piece of each user in the OFDM symbol is carried out Q road interleaving treatment;

(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, then send data;

(4) behind the receiving terminal receive data, first this data block symbols is removed the solution OFDM processing of CP and fast Fourier transform FFT computing, carry out again phase compensation and zero-suppress, then the OFDM symbol that obtains is carried out the deinterleaving of Q road, OFDM solution time-frequency resource allocating, rotation solution mediation decoding successively, obtain required data message, wherein

Described step (1) further comprises following content of operation:

(11) transmitting terminal calculates first the total G:G=OFDM_Num * OFDM_Length of the modulation symbol that all users send in each transmission course, 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 arranges in each OFDM symbol; Calculate again the modulation symbol of each user's transmission and count S:

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 formed by m bit mapping, be i.e. M=2 ^m, m=log then ₂M, the code length N:N=S of the transmission data of calculating each user behind coding * m; The information bit position long K:K=r * N of the transmission data of calculating again each user before coding, in the formula, code check r be span be (0,1] real number;

The K bit information that (13) 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 corresponding sign map 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 form 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) the symbolic vector piece after adopting spin matrix RM to modulation carries out four-dimensional rotation modulation, obtains the modulation diversity gain: the symbolic vector piece x that establishes behind the rotation modulation 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, u _iFour-dimensional row vector, the modulation symbol before the expression rotation modulation is processed, u _i' be u _iThe transposition column vector; x _iFour-dimensional row vector, the modulation symbol behind the expression multidimensional rotation modulation, x _i' be x _iThe transposition column vector; RM is the spin matrix of quadravalence, and the quadratic sum of its every row or every row all is 1, satisfies orthogonality between row vector or the column vector;

Each four-dimensional modulation symbol is that in-phase component and the quadrature component by two adjacent modulation symbol vectors consisted of, and namely each rotation modulation is processed two adjacent modulation symbol vectors in-phase component and quadrature component separately; So two modulation symbol vectors establishing before four-dimensional rotation modulation is processed are respectively A+Bj and C+Dj, when being respectively X+Yj and Z+Wj through these two values corresponding to modulation symbol vector behind the four-dimensional rotation modulation, 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,

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

The symbolic vector piece x that (15) will finish after rotation modulation is processed deposits memory in.

2. method according to claim 1, it 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; Namely the quantity L of each included user modulation symbol is set in each OFDM symbol: In the formula, OFDM_Length is the number of modulation symbols in each OFDM symbol, and P is all users' 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 so that each OFDM symbol comprises L * P modulation symbol, it occupies OFDM_Length subcarrier bandwidth at frequency domain; And always total OFDM_Num OFDM symbol occupies OFDM_Num time slot in time domain;

(22) 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.

3. method according to claim 2 is characterized in that: when transmitting terminal carries out the Q road when interweaving according to centralized OFDM pattern, described step (22) comprises following content of operation:

(221) symbolic vector of transmitting terminal after to the rotation modulation of same user in each OFDM symbol period carried out the time-frequency interleaving treatment, and the time-frequency interlacing rule is: the symbolic vector behind each user's the rotation modulation is stored in according to writing mode line by line Behind the interleaver of form, take out according to mode by column again, with the conversion that interweaves of the time-frequency by this symbolic vector, reduce in each rotation modulation time domain between two adjacent-symbol vectors and the correlation of frequency domain, in the formula, D is the dimension 4 of 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 sequentially carried out frequency-domain-interleaving and is processed, 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 processed together: first 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 with the Q road component in every group sequentially to the right one of loopy moving, 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 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.

4. method according to claim 3, it is characterized in that: described time-frequency two-dimensional interlacing rule is: will this same user, the modulation symbol of an interval W subcarrier bandwidth is made as one group on frequency domain, to choose two sequence numbers be f to hypothesis again ₁, f ₂Subcarrier, wherein, f ₂=f ₁+ W, W are two sub-carrier frequency point f ₁And f ₂Bandwidth granularity;

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 namely chosen first f in the 1st the OFDM symbol first 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, the like, according on time domain, from the 1st OFDM symbol choosing, select again to be separated by with the 1st OFDM symbol

Of individual OFDM symbol Individual OFDM symbol, and then select the 2nd OFDM symbol, select again to be separated by with the 2nd OFDM symbol

Of individual OFDM symbol

Individual OFDM symbol, the like, choose always

Individual OFDM symbol is selected and the again Individual OFDM symbol is separated by

(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:

$\{(f_1,1),(f_2,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}+1),(f_1,2),(f_2,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}+2),...,(f_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}),(f_2,\mathrm{OFDM}\_\mathrm{Num})\},$ After interweaving through the time-frequency two-dimensional of Q road component, the position coordinates of the frequency-domain and time-domain that it is occupied is the Q road component result of one of loopy moving to the right sequentially of original OFDM symbol just, is $\{(f_2,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}+1),(f_1,2),(f_2,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}+2),...,(f_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}),(f_2,\mathrm{OFDM}\_\mathrm{Num}),(f_1,1)\};$ 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 can fully effectively utilize frequency diversity and the time diversity of ofdm system so that the low time-frequency two-dimensional of computation complexity interweaves, and realize combined optimization with modulation diversity.

5. 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 respectively the IFFT computing according to the following equation:

In the formula, N is sub-carrier number, and X (k) is the complex signal of setting under the modulating mode, x (n) be the OFDM symbol in the sampling of time domain, 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 respectively cyclic prefix CP, eliminate the intersymbol interference that multi-path 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 successively each OFDM symbol.

6. method according to claim 3 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 respectively the IFFT computing according to the following equation:

In the formula, N is sub-carrier number, and X (k) is the complex signal of setting under the modulating mode, x (n) be the OFDM symbol in the sampling of time domain, 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 respectively cyclic prefix CP, eliminate the intersymbol interference that multi-path 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 successively each OFDM symbol;

Described step (4) further comprises following content of operation:

(41) behind the receiving terminal receive data, it is separated OFDM process: first each the OFDM symbol that receives is removed respectively CP, each the OFDM symbol that is about to receive is deleted respectively μ symbol of its head; Again each OFDM symbol is carried out respectively fast Fourier transform FFT computing according to the following equation: In the formula, N is sub-carrier number, and X (k) is the complex signal of setting under the modulating mode, x (n) be the OFDM symbol in the sampling of time domain, 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, in order to eliminate Multipath Transmission to the impact of data according to channel estimation value; The phase compensation formula is:

In the formula, x (t) is the symbolic vector in each OFDM symbol, h (t),

With | 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, namely delete step (31) then, is stored each OFDM symbol for long add zero in position of coupling IFFT computing length;

(44) the centralized or distributed OFDM pattern of selecting according to four-dimensional rotation modulation and step (21) is carried out the deinterleaving of corresponding Q road to the symbolic vector in each OFDM symbol and is processed, and namely carries out reverse process according to the rule of correspondence of step (22).

(45) proceed OFDM and separate the 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 sequentially, again be reduced to all users' of serial symbolic vector;

(46) adopt the maximum-likelihood demodulation mode that the symbolic vector that OFDM separates after the time-frequency resource allocating is rotated demodulation: take through the rotation planisphere after the multipath channel as demodulation reference constellation figure, 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 respectively shining upon the log-likelihood ratio of each bit that becomes each symbolic vector, 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.

7. method according to claim 6 is characterized in that:

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 first Q road component of order choice of modulation symbol, namely choose first the

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 ₂Then the Q road component of individual modulation symbol chooses f in the 3rd the OFDM symbol ₁The Q road component of individual modulation symbol, 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

Of individual OFDM symbol

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

Of individual OFDM symbol

Individual OFDM symbol, the like, choose 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; F at frequency domain 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:

$\{(f_2,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}+1),(f_1,2),(f_2,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}+2),...,(f_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}),(f_2,\mathrm{OFDM}\_\mathrm{Num}),(f_1,1)\},$

After the time-frequency two-dimensional deinterleaving through Q road component, the position coordinates of the frequency-domain and time-domain that it is occupied is the Q road component result of one of loopy moving left sequentially of original OFDM symbol just, is:

$\{(f_1,1),(f_2,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}+1),(f_1,2),(f_2,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}+2),...,(f_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}),(f_2,\mathrm{OFDM}\_\mathrm{Num})\},$ So that Q road quadrature component symbol all carries out place-exchange according to above-mentioned rule on time and frequency: $(f_1,1)\&RightArrow;(f_2,\mathrm{OFDM}\_\mathrm{Num}),(f_2,\mathrm{OFDM}\_\mathrm{Num})\&RightArrow;(f_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}),$ $(f_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2})\&RightArrow;(f_2,\mathrm{OFDM}\_\mathrm{Num}-1),(f_2,\mathrm{OFDM}\_\mathrm{Num}-1)\&RightArrow;(f_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}-1),$ $(f_1,\frac{\mathrm{OFDM}\_\mathrm{Num}}{2}-1)\&RightArrow;(f_2,\mathrm{OFDM}\_\mathrm{Num}-2),......,(f_2,\mathrm{OFDM}\_\mathrm{Num}/2+2)\&RightArrow;(f_1,2),$ (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, with the Q road component in this group successively one of loopy moving left, imaginary part and the real part that then will originally belong to the prosign vector 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 writing mode by column be stored in

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 first according to centralized frequency point allocation mode with distributed reduction become centralized after, carry out again above-mentioned steps (44) corresponding operating.

8. according to claim 6 or 7 described methods, it is characterized in that: in the planisphere of described step (46), every kind of combinatorial mapping of a plurality of bits becomes the corresponding symbol of certain point in the rotation planisphere, be 0 or 1 according to i position bit in these bit combinations, planisphere is divided into two set: the set of 0 constellation point and 1 constellation point are gathered; At this moment, judge that the computing formula that i position bit in the corresponding a plurality of bits of each symbol is respectively 0 and 1 probability is respectively: With

In the formula, { d _I0For this symbol that receives be the distance set of 0 all constellation point of dividing according to i position bit, { d _I1For this symbol that receives be the distance set of 1 all constellation point of dividing according to i position bit, natural number i is bit sequence in the bit combination; Calculate respectively thus the log-likelihood ratio of corresponding each bit of each symbol:

In the formula, b _vBy v bit in certain symbol of a plurality of bit mappings one-tenth 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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