CN100578947C - Transmitter based on multiple M dimension parallel modulaticn communication mode - Google Patents

Abstract

Said invention is based on a transmitter of M-ary parallel communication mode, which is characterized by combining M-ary modulation mode with traditional binary phase shift keying, quaternary phase shift keying and quadrature amplitude modulation, dividing data stream into multiplex parallel modulation, in each path, part of data is modulated by M-ary mode and part of data is modulated by traditional modulation mode, using quasi-orthogonal code character to construct as more as possible quasi-orthogonal code character, making optimal grouping, to raise demodulation property.

Description

A kind of transmitter based on the parallel modulation communication mode of multiple M dimension

Technical field:

The invention belongs to the modulation technique field in the mobile communication, specially refer to the transmitter that combines with the conventional modulated technology as parallel M dimension (M-ary) modulation system of spreading code set with grouping orthogonal code collection.

Background technology:

Along with the development of mobile communication technology, the user of mobile communication system constantly increases, and the desired service rate of user also improves constantly.The appearance of 3-G (Generation Three mobile communication system) has improved message transmission rate greatly, makes high speed data transfer become possibility.But along with the continuous rising of user's request, speed still becomes the bottleneck of high-speed data service.

" radio communication: principle is with practical " (Wireless Communication:Principles ﹠amp that the Electronic Industry Press published in 1998; Practice) 527 of a book pages-530 pages is example with narrow band code division multiple access mobile communication system (IS-95), introduced the application of quadrature M-ary modulation technique in code division multiple access (Code Division Multiple Access is called for short CDMA) communication system up link.Quadrature M-ary modulation technique is used M orthogonal intersection, chooses one of them sign indicating number by sending the data difference, sends in M the sign indicating number at every turn, thereby can transmit log ₂The M bit.Yet along with the growth of M, transmissible bit number growth can slow down gradually, and under the prerequisite that code length is fixed, available orthogonal code number M also is limited.283 pages-298 pages binary phase shift keying of being introduced (the Binary Phase Shift Keying of " Principles of Modern Communication " book that publishing house of Tsing-Hua University published in 1992, abbreviation BPSK), quaternary phase shift keying (Quadrature Phase Shift Keying, be called for short QPSK) until quadrature amplitude modulation (QuadratureAmplitude Modulation, be called for short QAM), it is modulator approach commonly used in the data communication, but only rely on the increase of number of modulation states to increase transmission rate, its transmissible bit number growth also can slow down gradually.So, use above-mentioned two kinds of modulation systems separately, spectrum efficiency is not high, and high speed data transfer can't be provided.

In cdma communication system, the spread spectrum code word is one of most important resource, and existing cdma system adopts Walsh-Hadamard (walsh-hadamard) orthogonal code more, but is under the prerequisite of N at code length, can only produce N available codeword.In order to improve the available codeword quantity of sign indicating number collection, " the spreading code building method that is used for cdma system " literary composition of the 7th curly hair table has proposed a kind of accurate orthogonal intersection set construction method in " international electronics is communicated by letter with The Institution of Electrical Engineers " magazine first phase in January, 2003, on the basis of Walsh-Hadamard orthogonal code, construct more quasiorthogonal code word, thereby can improve spectrum efficiency greatly.In addition, the code word that adopts this method construct to go out has accurate preferably orthogonal property, and its covariance matrix is a banded diagonal matrix.Under the prerequisite of this accurate orthogonal property, the algorithm complex of optimal detection can reduce greatly.But the quasiorthogonal code word that utilizes this method construct to come out does not see in the cdma communication system that adopts the M-ary modulation system so far as yet.

Summary of the invention:

The present invention proposes a kind of based on parallel modulation communication mode (the Multiple M-ary ParallelModulation Comminications of multiple M-ary, abbreviation MM-aryM) transmitter, to overcome the above-mentioned deficiency of M-ary modulation and traditional data modulation system, make full use of the spread spectrum code source, under the prerequisite that the code word number is fixed, increase the bit number of modulating on each symbol, combine with traditional modulator approach simultaneously on each road, thereby further improve the bit number of modulating on each symbol, increase spectrum efficiency, improve message transmission rate.

The present invention is based on the transmitter of multiple M dimension (M-ary) parallel communications mode, comprise: will import data 1 and be divided into multichannel through splitter 3, a part of data of every circuit-switched data are by modulator block Mi commonly used (sequence number i=1 wherein, ... n), comprise the modulation of binary phase shift keying, quaternary phase shift keying or quadrature amplitude, another part data by spreading code selector module Qi (i=1 ... n), adopt the M-ary modulator approach on each symbol, to modulate log ₂The P bit, wherein P is an available codeword number in the spreading code set of every road; After module Qi selects spreading code according to the input data, import multiplier Ci (i=1 jointly with the output of module Mi, ... n), finish spread spectrum, the output behind each road spread spectrum is formed and is closed the road signal by adder 4, by multiplier R1 scrambling, input data 2 are directly by multiplier R2 scrambling, and the signal after the two-way scrambling is formed baseband signal through adder 5, are modulated on the carrier wave by carrier modulation module 6 to send; It is characterized in that: described input data 1 are earlier by splitter 3, be divided into several, for each circuit-switched data, a part is by modulator block Mi commonly used, another part data behind input data selection spreading code, are jointly imported multiplier Ci with the output of module Mi by spreading code selector module Qi, finish spread spectrum, the output behind each road spread spectrum is again by adder 4;

The spreading code set that described spreading code selector module Qi is adopted can be the sign indicating number collection that traditional Walsh-Hadamard orthogonal code is formed, also can utilize the new code word of interpolation on the basis of traditional Walsh-Hadamard orthogonal code, thereby obtain to have the more code word of accurate orthogonal property, this code word building method is under the prerequisite of N at code length, can construct 2N-3 orthogonality quasiorthogonal code word preferably; In addition,, the spreading code set of structure is assigned to multichannel according to following principle of optimality: find so reasonably grouping, this grouping the transmission signal that might generate (M*N) arranged ^LKind, M is a code length, and N is the status number of conventional modulated mode, and L is a way; Calculate this (M*N) ^LIndividual signal signal distance between any two finds minimum sitgnal distancel.Seek repeatedly, up to the grouping of finding a minimum signal spacing maximum.

Corresponding to transmitter of the present invention, can adopt traditional maximum-likelihood sequence estimation (MaximumLikelihood Sequence Estimation at receiving terminal, be called for short MLSE) demodulation method, also can adopt maximum-likelihood sequence estimation (the Decision Feedback-MLSE of decision-feedback, be called for short DF-MLSE) demodulation method, in this demodulation scheme, demodulation is confined to a symbol, after symbol 1 demodulation finishes, its multipath information can feedback canceller for the influence of back symbol, the multipath information that so just can make full use of the back symbol participates in demodulation, analyzing the demodulation schematic diagram can find, the symbol numbers that participates in once judgement is many more, the energy that then participates in judgement is big more, the judgement accuracy is high more, so it is many more to participate in the symbolic number of once judgement, demodulation performance is good more, its limiting case is exactly the maximum-likelihood sequence estimation demodulation, certainly, along with increasing of the symbolic number that participates in once judgement, the complexity of demodulation also improves greatly, so the balance point of seeking demodulation performance and complexity is that decision participates in the once key of the symbolic number of judgement.

The M-ary modulation system that adopts in the existing communication system is that the bit number that can modulate on each symbol has only log under the prerequisite of M in code word ₂M, and along with the increase of M, the bit number growth rate of modulating on each symbol can slow down rapidly, makes spectrum efficiency reduce greatly; On the other hand, only adopt traditional modulator approach to improve spectrum efficiency, also be faced with identical problem by the enlarging state number.The transmitter that the present invention is based on the parallel modulation communication mode of multiple M-ary then will send data and be divided into multichannel by string and conversion, the traditional modulator approach of a part of The data on each road, another part The data M-ary modulator approach, both combinations, increased the bit number of modulating on each symbol, and, available codeword is divided into many groups, the code word number on each road is less relatively, with respect to present M-ary modulator approach, can reduce the influence of code word number growth, make full use of code source, improve spectrum efficiency for the bit number growth rate.In addition, the employed available codeword of M-ary modulation module can further improve the quantity of available codeword, thereby further improve spectrum efficiency under the prerequisite that code length is fixed if adopt quasiorthogonal code word building method.

The present invention is based on the transmitter of the parallel modulation communication mode of multiple M-ary, if adopt the speed of 3.84M chips/sec, the spread spectrum code length is 8, construct 12 available quasiorthogonal code words, 4 spreading codes are one group, divide three groups, and its character rate is 480k symbol/second. one road M-ary unit symbol is modulated 2 bits.If combine with quaternary phase shift keying, the unit symbol modulating data of one road signal is 4 bits, and data transfer rate is 5.76M bps, does not consider under the prerequisite of coding redundancy, and spectrum efficiency is 1.5; If combine with the modulation of 16 ary quadrature amplitude, the unit symbol modulating data of one road signal is 6 bits, and data transfer rate is 8.64Mbps, does not consider under the prerequisite of coding redundancy, and spectrum efficiency is 2.25.If the spread spectrum code length is one group of 16,4 spreading code, divide 7 groups, its character rate is 240k symbol/second.One road M-ary unit symbol is modulated 2 bits, corresponding quaternary phase shift keying, and its message transmission rate is 6.72M bps, does not consider under the prerequisite of coding redundancy, spectrum efficiency is 1.75; Corresponding 16 ary quadrature amplitude, its data transfer rate is 10.08M bps, does not consider under the prerequisite of coding redundancy, spectrum efficiency is 2.625.As seen, the present invention can effectively improve the availability of frequency spectrum, obtains higher message transmission rate.

Description of drawings:

Fig. 1 is the structural principle block diagram that the present invention is based on the transmitter of MM-aryM communication mode.

Fig. 2 is the quasiorthogonal code collection (M=8) that generates with the code word generation method that the present invention takes.

Fig. 3 is the autocorrelation matrix (M=8) of the quasiorthogonal code word that generates of the code word generation method taked with the present invention.

Fig. 4 is the block diagram of the decision-feedback MLSE demodulation of receiving terminal among the present invention.

Fig. 5 is the schematic diagram of the decision-feedback MLSE of receiving terminal among the present invention.

Fig. 6 is the QPSK of 3 road MM-aryM under the white Gaussian noise channel, the performance simulation result and the QPSK of 16QAM modulation, and the performance of 16QAM theoretical value is relatively.

Fig. 7 be DF-MLSE and two kinds of demodulation schemes of MLSE under Rayleigh (rayleigh) fading channel demodulation performance relatively.

Embodiment:

Below in conjunction with the description of drawings embodiments of the invention.

Embodiment 1:

In the present embodiment, in conjunction with the designed frame structure of up link, special uplink channel is divided into Dedicated Physical Data Channel (the Dedicated Physical Data Channel that carries data flow, be called for short DPDCH) and the Dedicated Physical Control Channel (Dedicated Physical Control Channel) that flows of bear control information, because DPDCH requires high-speed transfer, the transmission rate of DPCCH is then much lower relatively, so, in concrete the enforcement, the transmitter architecture of realization MM-aryM method as shown in Figure 1.Among the figure, data flow 1 is divided into several earlier by splitter 3, for each circuit-switched data, a part by modulator Mi commonly used (i=1 ... n), its bit number is relevant with the modulation system that Mi is adopted, and as corresponding to quaternary phase shift keying, the bit number by modulator Mi is 2 bits; Another part by spreading code selector Qi (i=1 ... n), the concentrated code word number of its bit number and every road sign indicating number is relevant, is M as code word number, and then its bit number is log ₂The M bit; After module Qi selects spreading code according to the input data, with the output of module Mi import jointly multiplier Ci (i=1 ... n), finish spread spectrum.Output behind each road spread spectrum is formed and is closed the road signal, by multiplier R1 scrambling by adder 4; Simultaneously, control information flow 2 is directly by multiplier R2 scrambling.Data flow after the scrambling closes the road signal and the control information flow signal is formed baseband signal through adder 5, is modulated on the carrier wave by carrier modulation module 6 to send.

Owing to adopted the modulation system of M-ary, so the quantity of the available codeword of spreading code set becomes the key factor of determination data transmission rate.If adopt traditional Walsh-Hadamard orthogonal code, be under the prerequisite of N then at code length, can only produce N available codeword, in order to increase the available codeword collection as much as possible, thereby raising message transmission rate, present embodiment has adopted a kind of new accurate orthogonal intersection set constructor mode, the i.e. new code word of interpolation on the basis of traditional Walsh-Hadamard orthogonal code, thereby obtain to have the more code word of accurate orthogonal property, the code word that adopts this method construct to go out has accurate preferably orthogonal property, and its covariance matrix is a banded diagonal matrix.Under the prerequisite of this accurate orthogonal property, the algorithm complex of optimal detection can reduce greatly.This code word building method is under the prerequisite of N at code length, can construct 2N-3 orthogonality quasiorthogonal code word preferably, on this basis, present embodiment divides into groups according to following principle to the quasiorthogonal code word that constructs again: find so reasonably grouping, this grouping the transmission signal that might generate (M*N) arranged ^LKind, M is a code length, and N is the status number of conventional modulated mode, and L is a way; Calculate this (M*N) ^LIndividual signal signal distance between any two finds minimum sitgnal distancel, seeks repeatedly, up to the grouping of finding a minimum signal spacing maximum.Thereby be applied in the transmitter based on the parallel modulation communication mode of multiple M-ary.The quasiorthogonal code building method of at first introducing present embodiment below and being adopted:

Consider that K road signal inserts a synchronization CDMA channel simultaneously, be equivalent to K user and insert a channel simultaneously, for this reason, below each user is regarded as in each road discuss, to be fit to use the term and the processing gimmick of common Multiuser Detection.Each user uses the frequency expansion sequence modulating data of own specific code length as N.Suppose that interchannel noise is additive white Gaussian noise (AWGN), the signal that receives is:

r＝A d+ n (f1)

Wherein A is the matrix of N * K, and K column vector represented K user's spreading code respectively; dBe data vector to be sent, length is K; nBe the white Gaussian noise vector after the sampling, length is N.

At first, rBehind one group of matched filter, obtain following signal:

y＝A ^T r＝R d+ z (f2)

R={r wherein _Ij}=A ^TA is the K * K autocorrelation matrix of K frequency expansion sequence, z=A ^T nIt is coloured noise.

Under additive white Gaussian noise (AWGN) channel, optimal detection can realize by the minimum Eustachian distance of looking between actual signal that receives and the alternative transmission signal, be shown below:

$\underset{\‾}{\overset{^}{d}}=\arg \min {\left|\right|\underset{\‾}{r}-A\underset{\‾}{d}\left|\right|}^2$ d∈{-1，+1} ^K (f3)

This formula is equivalent to following formula, promptly minimum quadratic component:

$\underset{\‾}{\overset{^}{d}}=\arg \min ({\underset{\‾}{d}}^{T}R\underset{\‾}{d}-2{\underset{\‾}{d}}^T\underset{\‾}{y}),\underset{\‾}{d}\∈{\{-1,+1\}}^K$

$=\arg \min ({\underset{\‾}{d}}^T(R-I)\underset{\‾}{d}-2{\underset{\‾}{d}}^T\underset{\‾}{y}),\underset{\‾}{d}\∈{\{-1,+1\}}^K---\left(f4\right)$

As everyone knows, Walsh-Hadamard orthogonal code is a kind of orthogonal code building method commonly used, can the recurrence structure.But the code word number that can construct at most when length is N is N.Therefore, the method for inserting new code word in the quasiorthogonal code building method utilization that present embodiment adopts is constructed more spreading code.The method of this interpolation can be destroyed the orthogonality of Walsh-Hadamard orthogonal code to a certain extent, be that the new interior code word of codeword set can exist correlation, so not only can reduce systematic function, require to utilize the associating multi-user test method shown in the formula (f4) at demodulating end simultaneously.

The method of the structure frequency expansion sequence set that proposes here is as follows:

w _2i-1＝ h _i (f5)

${\underset{\‾}{w}}_{2i}=\frac{1}{2}\underset{k=i}{\overset{i+3}{\mathrm{\Σ}}}{\underset{\‾}{h}}_k,i=1,...,N-3---\left(f6\right)$

w _2N-6+i＝ h _N-3+i，i＝1，2，3 (f7)

Wherein h _iBe H _NI the vector.Total 2N-3 of new frequency expansion sequence.The frequency expansion sequence that these neotectonicss go out has certain correlation in a particular range, form accurate diagonal matrix, thereby constructs a series of accurate orthogonal spreading sequences.Minimum range between its signal is the minimum signal distance of orthogonal spreading sequence

Corresponding the energy loss of a 3dB.Because the required memory length of storage correlation matrix is L=6, decoding complex degree is O (2 ⁷K).

With code length is 8 to be example, code word such as Fig. 2 of adopting this code word generation method to generate, and totally 13 available codeword, as seen from Figure 2, this yard set is made up of multivalued code.The autocorrelation matrix of all code words such as Fig. 3.

Ensuing work is exactly to find out suitable grouping from these 13 code words, is divided into 3 groups, every group of 4 sign indicating numbers, and having a code word at last need not.The principle of the best packet that present embodiment proposes is: find so reasonably grouping, this grouping the transmission signal that might generate have 8 ³Kind of (M-ary+BPSK), calculate this 8 ³Individual signal signal distance between any two finds minimum sitgnal distancel.Seek repeatedly,, can see in experimental system subsequently that the grouping of this optimum can be used and performance reaches error rate requirement up to the grouping of finding a minimum signal spacing maximum.

According to the span of multivalued code, the possible value of code word spacing has 0,4,8,12,16,20,24 etc., the multiple with 4 increases progressively, so, the code distance table of various grouping situation correspondences is as shown in table 1, and wherein the code distance that may send between the signal of every this grouping of digitized representation of form has how many times to get its possible value, because under the very big situation of code distance, the probability that the demodulation mistake occurs levels off to 0, so only listed the data of several less code distances in the table.Here only list two groups of non-optimum groupings and divide into groups relatively with optimum, in fact Fen Zu situation has a variety of.Adopted a kind of method of the optimum grouping of searching of simplification in the present embodiment, promptly sought the grouping of minimum distance maximum, under the identical situation of minimum distance, sought in the minimum grouping of this minimum distance occurrence number.By table 1 as seen, among three kinds of groupings, minimum distance is 8, the second kinds of groupings, and code distance to occur be 8 least number of times, so can select for use.

Table 1: the code distance table of several grouping situation correspondences

Transmitter corresponding to present embodiment based on the parallel modulation communication mode of multiple M-ary, optimum detection methodology at receiving terminal is maximum-likelihood sequence estimation (MLSE), its basic thought travels through all possible code word combination exactly and calculates all possible transmission signal, make Maximum Likelihood Detection with received signal, thereby obtain demodulation result.But because the influence of multipath fading, this demodulation method must adopt the Viterbi demodulation, and computation complexity is too high.Be to reduce the demodulated complex degree, present embodiment has adopted the maximum-likelihood sequence estimation (DF-MLSE) of decision-feedback, its demodulation block diagram such as Fig. 4 at receiving terminal.At the limited symbol detector 8 of input received signal 7 processes, and the testing result 9 process delayer Di of output (i=1 ... n), the result who obtains respectively with each the footpath channel estimating parameter Ei (i=1, ... n) multiply each other, and obtain feedback signal 11, feed back to input by adder 10.

Fig. 5 is the schematic diagram of decision-feedback maximum-likelihood sequence estimation demodulation: Pi (i=1, ... n) represent i footpath in the multipath, Si (i=1, ... n) represent i symbol, symbol of demodulation limitation, after a symbol demodulation finished, its multipath information can feedback canceller for the influence of back symbol, the multipath information that so just can make full use of the back symbol participates in demodulation, and each energy that is used for adjudicating that can be collected is directly labelled with shade in 1 symbol.Analyze according to Fig. 5 schematic diagram, the symbolic number that participates in once judgement is many more, and the area of dash area is just big more.Because it is big more to participate in the energy of judgement, the judgement accuracy is high more, so can infer, the symbolic number that participates in once judgement is many more, and demodulation performance is good more, and its limiting case is exactly the maximum-likelihood sequence estimation demodulation.Certainly, along with increasing of the symbolic number that participates in once judgement, the complexity of demodulation also improves greatly, so the balance point of seeking demodulation performance and complexity is that decision participates in the once key of the symbolic number of judgement.

In order to prove that the performance based on the transmitter of the parallel modulation communication mode of multiple M-ary and corresponding receiver of present embodiment can satisfy the requirement of mobile communication system in the practical application, present embodiment has provided the partial simulation result.The emulation of present embodiment is finished on the SPW emulation platform, and code length is 8, the simulated channel that adopts the SPW analogue system to carry, and carrier frequency is the 2.0G hertz, spreading rate is the 3.84M hertz.

Fig. 6 has described to adopt in the present embodiment under the white Gaussian noise channel 3 tunnel parallel modulation, each road with M-ary respectively with quaternary phase shift keying, 16 ary quadrature amplitude method combinations, receiving terminal adopts the performance simulation result of decision-feedback maximum-likelihood sequence estimation demodulation method and adopts quaternary phase shift keying separately, 16 ary quadrature amplitude methods, receiving terminal adopt the performance of the theoretical value of corresponding demodulation method to compare.Wherein transverse axis is represented signal to noise ratio Eb/No, the longitudinal axis is represented bit error rate, what curve A was described is the demodulation performance that M-ary combines with 16 ary quadrature amplitude, what curve B was described is the demodulation performance that adopts 16 ary quadrature amplitude separately, what curve C was described is the demodulation performance that M-ary combines with quaternary phase shift keying, and what curve D was described is the demodulation performance that adopts quaternary phase shift keying separately.As seen from Figure 6, under the white Gaussian noise channel, adopt the transmitter of the parallel modulation communication mode of described 3 road M-ary of present embodiment, its demodulation performance and corresponding quaternary phase shift keying, the demodulation performance difference of 16 ary quadrature amplitude methods within 1dB, thereby proved the validity of this modulation system.

Fig. 7 has compared under the rayleigh fading channel, and receiving terminal adopts the demodulation performance of decision-feedback maximum-likelihood sequence estimation and two kinds of demodulation schemes of maximum-likelihood sequence estimation in the present embodiment.Wherein transverse axis is represented signal to noise ratio Eb/No, the longitudinal axis is represented bit error rate, what curve E described is moving velocity of terminal 120 kilometer per seconds, multipath is under the situation in 6 footpaths, transmitting terminal adopts 3 tunnel parallel modulation, receiving terminal adopts the demodulation performance of decision-feedback maximum-likelihood sequence estimation, what curve F described is at moving velocity of terminal 0 kilometer per second, multipath is under the situation in 6 footpaths, transmitting terminal adopts 3 tunnel parallel modulation, receiving terminal adopts the demodulation performance of decision-feedback maximum-likelihood sequence estimation, what curve G described is at moving velocity of terminal 0 kilometer per second, multipath is under the situation in 6 footpaths, transmitting terminal adopts 1 tunnel parallel modulation, receiving terminal adopts the demodulation performance of decision-feedback maximum-likelihood sequence estimation, and what curve H described is at moving velocity of terminal 0 kilometer per second, and multipath is under the situation in 6 footpaths, transmitting terminal adopts 1 tunnel parallel modulation, receiving terminal adopts the demodulation performance of maximum-likelihood sequence estimation (Viterbi demodulation),, compares the performance of the following two kinds of demodulation schemes of the same terms emphatically here, promptly parallel modulation way is 1 the tunnel, movement velocity is 0, and multipath is 6 footpaths, corresponding to curve G and H, wherein the relative power in each footpath is respectively 0dB,-3dB ,-6dB ,-9dB,-12dB,-15dB, each footpath time delay is respectively 0,1,2,3,4,5 chips.As seen from Figure 7, adopt decision-feedback maximum-likelihood sequence estimation demodulation method, its demodulation performance only than about maximum-likelihood sequence estimation demodulation method difference 1dB, is higher than in signal to noise ratio under the condition of 12dB, can reach 10 ^-5Bit error rate, it is emphasized that because this emulation of doing of present embodiment just for the performance difference of two kinds of demodulation methods relatively, is not also considered the performance gain that technology such as encoding and decoding and diversity are brought.So, in the middle of the practical application, have better demodulation performance.

Claims (1)

1. transmitter based on multiple M-ary parallel communications mode, comprise: will import data (1) and be divided into multichannel through splitter (3), a part of data of every circuit-switched data are the modulator block (Mi) commonly used of i by sequence number, carry out binary phase shift keying, quaternary phase shift keying or quadrature amplitude modulation, another part data are the spreading code selector module (Qi) of i by sequence number, adopt polynary modulator approach to modulate log on each symbol ₂The P bit, wherein P is an available codeword number in the spreading code set of every road; After the spreading code selector module (Qi) of sequence number i is selected spreading code according to the input data, import the multiplier (Ci) of sequence number i jointly with the output of the modulator block (Mi) of sequence number i, finish spread spectrum, output behind each road spread spectrum is by adder (4), form and close the road signal, by first multiplier (R1) scrambling, input data (2) are directly by second multiplier (R2) scrambling, signal after the two-way scrambling is formed baseband signal through adder (5), is modulated on the carrier wave by carrier modulation module (6) to send; It is characterized in that: described input data (1) are divided into several by splitter (3) earlier, pass through modulator block (Mi) commonly used for each circuit-switched data part, another part data are the spreading code selector module (Qi) of i by sequence number, behind input data selection spreading code, import the multiplier that sequence number is i (Ci) jointly with the output of the modulator block (Mi) of sequence number i, finish spread spectrum, the output behind each road spread spectrum is again by adder (4); Described sequence number is that the spreading code set that the spreading code selector module (Qi) of i is adopted is the new code word of interpolation on the basis of traditional orthogonal walsh-Hadamard orthogonal code, thereby obtains to have the more code word of accurate orthogonal property; The quasiorthogonal code of structure is divided into multichannel: find so reasonably grouping, this grouping the transmission signal that might generate (M*N) arranged ^LKind, M is a code length, and N is the status number of conventional modulated mode, and L is a way; Calculate this (M*N) ^LIndividual signal signal distance between any two finds minimum sitgnal distancel; Seek repeatedly, up to the grouping of finding a minimum signal spacing maximum; Described sequence number i=1,2 ... n.

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