CN101488930A - Multi-code OFDM transmission method and equipment thereof - Google Patents

Abstract

The invention discloses a multicode OFDM (Orthogonal Frequency Division Multiplexing), including the following steps: an OFDM system is determined according to the used frequency band and traveling speed so as to obtain multipath OFDM symbols through series-parallel exchange; a set of band spectrum code words is used for having band spectrum modulation processing of the multipath OFDM symbols containing data information; and the multipath symbols after band spectrum modulation processing are respectively added with recirculating prefix signs that are emitted through a radio-frequency system after combination. The set of band spectrum code words in the invention is a set of code words that enables frequency code interference ICCI among different subcarriers to be equal to zero or very small.

Description

Multi-code OFDM transmission method and equipment thereof

Technical field

The present invention relates to a kind of many yards orthogonal frequency-division OFDM wireless communication fields, particularly multi-code OFDM transmission method and equipment.The invention still further relates to how little (fan) district and many antennas multiple-input, multiple-output (MIMO) wireless mobile communications field, particularly reduce presence of intercell interference and many inter-antenna interference, provide OFDM with method and equipment thereof between organizing frequently.

Background technology

Orthogonal frequency-division (OFDM) transmission technology has been widely used in communication system, in mobile radio system, because the influence of propagation conditions will adopt various code interleavings and diversity to resist the various influences of fading channel usually.

OFDM is a kind of frequency multiplexing technique in essence, in multiple access communication, can not distribute to different addresses, and adopt OFDMA as multi-access mode usually with single carrier wave as minimum transmission units, has so just reduced efficiency of transmission.In addition, for reduce the outer interference to nearby frequency bands of frequency band usually in passband spendable subcarrier only account for below 85% of bandwidth, this also is a defective.In addition, ofdm system usually can not identical networking, and its spectrum efficiency reduces greatly under how little (fan) district's networking condition.

Code division multiple access (CDMA) is a kind ofly to be divided into the multiple access technology on basis with waveform, is widely used in mobile communication, and can makes spectrum use factor reach 1, promptly at the identical frequency spectrum of adjacent little (fan) district use.

Asynchronous CDMA Systems is owing to disturb (MAI) and intersymbol interference (ISI) between its address, the available address number is had a greatly reduced quality in the multipath transmission environment, only is about 1/3 of orthogonal code quantity usually.

LAS-CDMA technology [1] has been used the sign indicating number with zero correlation window, thereby makes MAI and ISI reduce to zero in window, thereby does not need the accurate power controls technology, has improved systematic function.But can use the quantity of sign indicating number limited by window size in LAS-CDMA technology, usually the yardage that can utilize is N/W, N is the length of sign indicating number, W is a length of window, unit is chip Tc, guarantee not to be subjected to propagation effect, and enough W length must be arranged, thereby available quantity is had a greatly reduced quality, and how many DMA do not how than traditional C.

OFDM and CDMA are combined seemingly a kind of good method.Mainly contain three kinds at present: CDMA multiple carrier (MC-CDMA) [2], multicarrier directly expand CDMA (MC-DS-CDMA) [3], and this dual mode is mainly used in and improves the OFDM performance, do not have interference between the subcarrier.Overlapping between multitone CDMA (MT-CDMA) [4] subcarrier owing to having, thus the system transmissions ability improved.

Yet, simple MT-CDMA, owing to exist the frequency sign indicating number between different sub carrier to disturb (ICCI), disturb (ICI) between subcarrier in the ofdm system and be not only, usually ICCI can not reduce by improving transmitting power, strengthens because signal strengthens to disturb also, so its bit error rate of MT-CDMA (BER) curve occurs smooth along with the increase of signal to noise ratio (Eb/NO), at this moment noise recedes into the background, and ICCI has limited performance improvement.

Can use multiuser detection in order to reduce (ICCI), but when the quantity of subcarrier and sign indicating number when all very big, unavailable in fact, only be suitable for minority subcarrier (as 2,4,8) usually.

As if the sign indicating number that uses the LAS-CDMA technology or have zero (or low) associated window can improve MT-CDMA systematic function [5], but in fact ICCI is not only relevant with the mutual character of intersymbol, also relevant with the auto-correlation by turn and the cross-correlation function of sign indicating number.Because have zero or the sign indicating number of low associated window no longer have zero or the character of low correlation at intercarrier, be added in sometimes can be between a plurality of sign fields suitable greatly, and do not change with the increase of signal intensity.

The phase mutual interference of the sign indicating number between subcarrier is divided into 2 kinds, and promptly alien frequencies has only these two kinds of interference all to reduce with sign indicating number and the different sign indicating number of alien frequencies, and system is just available.

Thereby to MC-ofdm system, the spreading code that at first require to use has good auto-correlation function and cross-correlation function, in same carrier wave, disturbs between the spreading code and should eliminate or seldom.Secondly the frequency intersymbol cross-correlation function Rcf (t) of sign indicating number also should have good character between subcarrier, promptly preferably is zero everywhere.Yet this is impossible.Because at this moment propose strict more requirement than the spreading code of common CDMA, thereby its quantity also lacks than the sign indicating number of various zero correlation windows, and perhaps zero correlation window is littler.

The present invention proposes a kind of multi-code OFDM transmission method, its carrier spacing is the inverse of symbol duration, identical with OFDM, because relevant spreading codes such as use make transmission rate increase more than the several times and can use for many sub-districts owing to use special spreading code, when transmission rate doubled, its intersymbol interference frequently was zero in theory.

Summary of the invention

A kind of the more code OFDM transmission method and the equipment thereof higher have been the purpose of this invention is to provide than the OFDM availability of frequency spectrum.

A kind of multi-code OFDM transmission method may further comprise the steps:

1) the OFDM symbol that multichannel is contained primary data information (pdi) carries out serial to parallel conversion, so that obtain multichannel OFDM branch data;

2) utilization waits one group of associated code that waits as spreading code in the correlated series, and described multichannel OFDM branch data is carried out band spectrum modulation processing respectively;

3) the described multichannel OFDM branch data through band spectrum modulation processing is added the Cyclic Prefix symbol respectively, launch by radio system through the combination back then.

Wherein, associated code such as described a group is the group code that all yards cross-correlation coefficient all equates.

Wherein, the minimum unit sign indicating number of described associated code such as grade is 4 bit code, comprises the described minimum unit sign indicating number of two classes,

First kind minimum unit sign indicating number comprises: 1110; 1101; 1011; 1000

The second class minimum unit sign indicating number comprises: 1111; 1010; 1100; 1001.

Wherein, utilize complementary converter that first kind minimum unit sign indicating number is carried out complementary conversion, obtain the relevant mutual-complementing code of four corresponding first kind minimum units: 1011; 1000; 1110; 1101;

Utilize complementary converter that the second class minimum unit sign indicating number is carried out complementary conversion, obtain the relevant mutual-complementing code of four second corresponding class minimum units: 1010; 1111; 1001; 1100.

Wherein, utilize combiner that described four first kind minimum unit sign indicating numbers are carried out combination in any, form code length and be the relevant spreading codes such as the first kind of 4 integral multiple; Perhaps

Utilize combiner that described four second class minimum unit sign indicating numbers are carried out combination in any, form code length and be the relevant spreading codes such as second class of 4 integral multiple.

Wherein, described combination in any comprises: a minimum unit sign indicating number is added up; A minimum unit sign indicating number and its radix-minus-one complement are added up; And different minimum unit sign indicating numbers added up.

Wherein, utilize combiner that the relevant mutual-complementing code of described four first kind minimum units is carried out combination in any, form code length and be the relevant complementary spreading codes such as the first kind of 4 integral multiple; Perhaps

Utilize combiner that the relevant mutual-complementing code of described four second class minimum units is carried out combination in any, form code length and be the relevant complementary spreading codes such as second class of 4 integral multiple.

Wherein, described combination in any comprises: the relevant mutual-complementing code of a minimum unit is added up; The relevant mutual-complementing code of a minimum unit and its radix-minus-one complement are added up; And the relevant mutual-complementing code of of a sort different minimum units added up.

Wherein, the described associated code that waits as spreading code forms by one of following steps:

Utilize combiner to make up relevant spreading codes such as the described first kind and relevant complementary spreading codes such as the first kind; Perhaps

Utilize combiner to make up relevant spreading codes such as described second class and relevant complementary spreading codes such as second class.

A kind of multi-code OFDM transmission equipment comprises:

The OFDM symbol that multichannel is contained primary data information (pdi) carries out serial to parallel conversion so that obtain the device of multichannel OFDM branch data;

In the correlated serieses such as utilization the one group associated code that waits as spreading code carries out the device of band spectrum modulation processing respectively to described multichannel OFDM branch data;

Described multichannel OFDM branch data through band spectrum modulation processing is added the Cyclic Prefix symbol respectively, then the device of after making up, launching by radio system.

Advantage of the present invention is, than the ofdm system spectrum utilization efficiency high many and can how little (fan) district identical networking.

Description of drawings

Fig. 1 is the block diagram of MC-OFDM system;

Fig. 2 is the frequency configuration figure of MC-OFDM;

Fig. 3 is S=8, a kind of correlated series that waits during N=16;

Fig. 4 is 16 sequences through a district after the expansion of [H] matrix;

Fig. 5 obtains X sequence and Y sequence through adding related complementary sequence;

Fig. 6 is the frequency intersymbol correlation function value of segment encode 1 and all the other each yards on Fig. 3 sequence;

Fig. 7 is different interval S=1 and S=5 frequency intersymbol correlation;

Fig. 8 is that same sub-district is at multidiameter Δ τ=1T _cCross correlation value between time-frequency code.

Embodiment

Prior OFDM system can not identical networking under mobile communication environment, thereby spectrum utilization efficiency greatly reduces, and is reduced to below 1/7 for its spectrum efficiency of common Cellular Networks, and is of the present invention and advantage MC-ofdm system just is can identical networking.Method provided by the invention can make how little (fan) interval interference be reduced to below the limit that can receive.

Many antennas (multiple-input, multiple-output MIMO) transmission technology is to improve transmission rate and efficient and efficient method in reliability.Usually require rich beyond-the-horizon communication environment to make the transmission parameter statistics of many antennas independent.But when portable terminal and antenna for base station during, promptly poor scattering environments in sighting distance (LOS) scope, at this moment the effectiveness of MIMO completely without.If use many antenna provided by the invention to use different code characters, no matter can both normally effectively work under the condition when poor scattering or during rich scattering.

Be elaborated below in conjunction with accompanying drawing.

According to an aspect of the present invention, this has provided a kind of many yards Orthodoxy Frequency Division Multiplexs (MC-OFDM) transmission method, may further comprise the steps:

1) at first construct correlated series (sign indicating number) such as a group and realize many cell transmission, its basic parameter is that the length (being number of chips) of sign indicating number is N, N=2 ⁿConstruct one group S and wait associated code, as S 2 the time, the minimal cross correlations value Rs (S of intersymbol _i, Sj, 0)≤4/N.Cellular mobile communications networks networking requirement S 〉=7.Correlated serieses such as requirement have the pseudo noise characteristic, i.e. the mould absolute value of each component coefficient of its discrete Fourier (Fourier) conversion DFT equates.The absolute value that is to say each discrete spectrum component is identical, has the characteristic of similar noise.

The known sequence that is generated by the Bent function has above-mentioned characteristic, and similarly, almost the sequence of Bent function generation also has almost pseudo noise characteristic.

If require cross correlation value Rs (Si, Sj, 0)≤1/4, the 1/4＜1/e between sequence to go out N 〉=16 so.

2) wait correlated series according to existing one group S, carry out the expansion of sequence number, particularly use Walsh-Hadamard matrix to carry out sequence extension by the Hadamard matrix of a standard N * N.

The method of expansion is by waiting the correlated series battle array [S] and the direct product (Kronecker Product) of Hadamard matrix [H] to expand, obtaining S and organize every group of N sequence M=S * N sequence altogether.

Because the pseudo-randomness of sequence between them and the interference (ICCI) between the different sign indicating numbers of different frequency should be minimum.Work as N=16, Rs (Si, Sj, 0)=1/4 o'clock, it is available to have 128 sequences (sign indicating number).Can be divided into 8 sub-districts (greater than 7).

3) disturb in order to eliminate multipath, can eliminate the multipath interference of a chip (Tc) by constructing its relevant mutual-complementing code, because a symbol duration of ofdm system is long, the duration of its Cyclic Prefix (CP) is enough usually greater than the multipath transmisstion time so eliminate the correlation of the intersymbol of a Tc.

Because the length of sign indicating number is N=2 ⁿ=4m, m are positive integer, so relevant mutual-complementing code can be generated by the relevant mutual-complementing code of corresponding 4 bit codes.

4 bit codes can be divided into two classes, 4 sign indicating numbers of every class quadrature of being correlated with, and they are:

The first kind:

Its relevant mutual-complementing code of +++-is+-++

++—+ +———

+—++ +++—

+——— ++—+

Second class:

++ ++ its relevant mutual-complementing code is+-+-

+—+— ++++

++—— +——+

+——+ ++——

So just obtain S the related complementary sequence that the N position is long, claim that former sequence is the X sequence, its related complementary sequence is the Y sequence.Apparent Y sequence also is the related complementary sequence of correlated series such as a group, that is to say, waits the related complementary sequence of correlated series to be still one and waits correlated series.Especially when the X sequence be Bent or almost during the Bent sequence, its related complementary sequence Y also is one group of Bent or Bent sequence almost.

4) the length T s=2NTc of a selected sequence, it also is useful symbol duration of ofdm system, thereby the correlation function of intersymbol can be expressed as frequently: R _Cf(C _i, C _j, f _l, f _m, t), because the intercarrier frequency spectrum of ofdm system is $k{f}_s=\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="A200810000536E00213.png,A200810000536E00221.png"\; state="\{\{state\}\}">k</figure-callout>}\frac{1}{\mathrm{Ts}},$ R=1,2 ... so the cross-correlation function between its frequency is:

${\&Integral;}_0^{T_s}\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="A200810000536E00212.png,A200810000536E00231.png"\; state="\{\{state\}\}">cos</figure-callout>}2\mathrm{\&pi;k}\frac{1}{T_s}\mathrm{tdt}={\&Integral;}_0^{T_s}\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="A200810000536E00212.png,A200810000536E00231.png"\; state="\{\{state\}\}">cos</figure-callout>}2\mathrm{\&pi;k\&Delta;ftdt},\mathrm{\&Delta;f}=\frac{1}{T_s}$

Following formula is the difference frequency term of correlation between frequency, itself and a filtering frequently.Each place value of note sign indicating number is

Thereby the correlation function of intersymbol is frequently

$R_{\mathrm{cf}}(C_i,C_j,k,t)$

$=\underset{l}{\overset{2N-1}{\mathrm{\&Sigma;}}}{\&Integral;}_0^{T_c}{C}_i^l{C}_{\mathrm{<figure-callout\; id="2"\; label="j\; l\; cos"\; filenames="A200810000536E00212.png,A200810000536E00231.png"\; state="\{\{state\}\}">j</figure-callout>}}^l\cos 2\mathrm{\&pi;k\&Delta;ftdt}$

$=\underset{l}{\overset{2N-1}{\mathrm{\&Sigma;}}}{\&Integral;}_{i{T}_c}^{{(i+1)T}_c}{C}_i^l{C}_{\mathrm{<figure-callout\; id="2"\; label="j\; l\; cos"\; filenames="A200810000536E00212.png,A200810000536E00231.png"\; state="\{\{state\}\}">j</figure-callout>}}^l\cos 2\mathrm{\&pi;k\&Delta;ftdt}$

$\underset{l}{\overset{2N-1}{\mathrm{\&Sigma;}}}{\&Integral;}_{i{T}_c}^{{(i+1)T}_c}{C}_i^l{C}_{\mathrm{<figure-callout\; id="2"\; label="j\; l\; cos"\; filenames="A200810000536E00212.png,A200810000536E00231.png"\; state="\{\{state\}\}">j</figure-callout>}}^l\cos 2\mathrm{\&pi;k\&Delta;ftdt}$ Be actually the integration of intercarrier difference frequency, be that difference frequency is 1,2 ... the segmentation in individual cycle (2N section) integration is because its integrated value is the 2 π k Δ ftdt of S, so in the Ts interval, k=1 is arranged, 2 ... the individual cycle is so its increment is symmetrical for Ts/2, if so CiCj is antisymmetric then the cross correlation value of frequency intersymbol with respect to the Ts/2 place, that is intersymbol interference frequently (ICCI) is zero.

Because R _Fc(k t) is the cycle, thus Ts interval itself and be zero.If thereby

Correlation identical entirely, ICCI also is zero.Obviously this desirable group code of structure is impossible, if but sign indicating number has enough randomness, and its intersymbol interference frequently should be minimum.

5) according to frequency range and the translational speed used, determine every major parameter of an ofdm system, calculate correlation bandwidth and correlation time so that determine the duration T s of symbol.According to the respective propagation condition, the multidiameter size obtains the effective duration T b and guard time Tg (time of the cyclic prefix CP) Ts=T of symbol _b+ T _g, obtain frequency interval Δ f=1/T thus _b

Determine FFT size and sample frequency, determine the sampling number of Tb and CP, determine available carrier wave number (reserving enough protection frequency bands), data carrier and pilot frequency carrier wave number.

Because present ofdm system has standard, might as well select the standard of a preparation to existing OFDM upgrading

2N=2 ⁿ, n is a positive integer, n 〉=5

Can obtain the length of chip Tc, constraints be 1/Tc＜＜W, determined N thus.

Calculate actual MC apread spectrum bandwidth Wk, get rolloff-factor α=0.25 usually, Wk=W-1.25/Tc

When $(m_c-1)\frac{1}{T_s}\&GreaterEqual;W_k$ The time extension frequency carrier count m _k=m _c,

When $(m_c-1)\frac{1}{T_s}<W_k,$ m _k＜m _c, reduce Wk and make $W_k=(m_c-1)\frac{1}{T_s}$

Final more definite extension frequency carrier that can transmit data is counted m _k(removing pilot frequency carrier wave) promptly obtains available transmission rate.

6) spread spectrum is counted the selection of K

Every district has N spreading code to be divided into 2 sections,

Epimere is a sign indicating number 1 to N/2 (C ₁, C ₁... C _N/2)

Hypomere is that sign indicating number N/2+1 is to N (C _N/2+1... C _N)

Every section is divided into 2 groups again, N/4 sign indicating number before and after being respectively, and for example epimere is C for one group ₁, C ₁... C _N/4

Each ofdm system is selected any group code, and different little (fan) district or antenna can be selected the corresponding code character in different districts.

7) Cyclic Prefix adds

Each code length is the 2N position, is divided into X sign indicating number and relevant complementary Y sign indicating number, and two sections of the Cyclic Prefix that original OFDM cyclic prefix CP interval is divided into the Cyclic Prefix of X sign indicating number and Y sign indicating number are added in respectively before the X sign indicating number and before the Y sign indicating number.

The present invention has the effect of following particular importance

1) increases substantially the transmission rate and the spectrum utilization efficiency of ofdm system; Can satisfy the needs of new generation of wireless mobile communication;

2) can make ofdm system identical networking under how little (fan) district environment, this also corresponding spectrum utilization efficiency that improved;

3) be used for the multiple-input, multiple-output mimo system and can not reduce transmission speed and quality at various communication environments;

4) can make existing ofdm system increase transmission speed and improve spectrum efficiency with straightforward procedure;

Embodiment

Below be example with the WiMAX system, how explanation constructs a MC-OFDM system step by step

1) parameter of the OFDM of extraction WiMAX system

Table one OFDM parameter

The distribution of table two downstream link sub-carrier

2) select spreading code length

Make 2Tc＜T _g

4Tc=11.2us=T is got in 2Tc＜11.2 _{The g tacit agreement}

TC=2.8 μ s 2N=T _b/ Tc=32, N=16 T _b=32 * 3.8=89.6us, guard time Tg=4Tc=11.2us

3) select the Bent sequence, when N=16, relevant between minmal sequence is 4/N=1/4

This moment S=8

S ₁ ++++ ++++ ++++ ++++

S ₂ +++— +++— +++— ———+

S ₃ ++++ ++—— +—+— —++—

S ₄ ++++ +——+ ++—— —+—+

S ₅ +++— ++—+ +——— +—++

S ₆ ++++ +—+— +——+ ——++

S ₇ +++— +——— +—++ ++—+

S ₈ +++— +—++ ++—+ +———

4) determine the available carrier wave number

Get α=0.25 o'clock

W _k＝(1+α)f _c＝446.43KHZ

MC-OFDM available bandwidth and available carrier wave number

W(MHZ)

1.25

5

10

20

W(KHZ)	803.571	4553.57	9553.57	19553.57
					The available carrier wave number	72	408	856	1752
The data carrier number	72	384	768	1536

5) make up 8 groups of orthogonal sequences (referring to Fig. 4)

Being constituted with [H] and generated its relevant mutual-complementing code by [S], below is district's 16 sign indicating number examples (having 8 districts)

6) N sequence to a district adds the Cyclic Prefix chip respectively to its X part and Y part, and Fig. 5 represents routine S ₂District's sign indicating number adds 2 cyclic code prefix chips respectively

7) spreading code of selecting each carrier wave to use

At first analyze the frequency intersymbol cross-correlation function of above-mentioned code character, for example only differing 16 Δ f in the even number frequency exists correlation in said system intersymbol interference frequently for this reason, and all is zero except that 2 kinds of situations.Particularly at sign indicating number 18 intersymbols in 8 sections of the sign indicating numbers, the intersymbol correlation is non-vanishing only at 4 Δ f frequently, 8 Δ f, totally 5 kinds of situations of 12 Δ f are non-vanishing, and homophase is identical with orthogonal terms, and has the interference that correlation is non-vanishing when 4 intersymbols have only frequency interval to be 8 Δ f in the group of each section, sees Fig. 6.

A spot of frequency intersymbol interference can be eliminated by receiving to handle, and for example utilizes many interference detection techniques to eliminate.

8) code character of selecting different little (fan) to distinguish

Different little (fan) district uses the not sign indicating number of same district, because being one, the S sign indicating number waits associated code, its minimum value is 4/N, when N=16 when identical networking, its correlation be 1/4 ， And and intersymbol interference frequently less than 1/4, consider the gain difference of different districts antenna, exist the antenna beam lap just can produce intersymbol interference frequently in principle, this will use other technologies to reduce.

9) performance evaluation when having multipath transmisstion

Fig. 7 is given in when having 1Tc (2.8us) multidiameter, the frequency intersymbol cross-correlation situation in group of above-mentioned sign indicating number, and intersymbol interference frequently only occurs when the odd multiple number of frequency interval as can be seen.In one section, disturb maximum be-6db, and noiseless during with frequency.Because multidiameter itself the low 10db of amplitude about, so the intersymbol interference of multidiameter time-frequency is being arranged about-15db.If selecting one group of 4 sign indicating number, its maximum is-9db, and is just littler.

10) calculate transmission rate and spectrum utilization efficiency

The transmission rate of MC-OFDM system is:

R _mc＝K ₁K ₂K ₃K ₄

K wherein ₁Be the spread spectrum sub-carrier number

K ₂Be spread spectrum subcode number

K ₃Be the every symbol transmission speed of every subcarrier

K ₄Bit number for every symbol transmission

When using QPSK, the K in the last example ₄Equal 2, when using 2,4,8, in the time of individual yard, the transmission rate and the spectrum efficiency of different system bandwidth see the following form:

11) selection of code length N

If increase the length of N, little (fan) interval maximum intersymbol cross correlation value is frequently further reduced, when N=32, can obtain S=7, Rs (0)=4/N=1/8 (-9db), and maximum available yardage is 16, increased by one times, though the available carrier wave number reduces, transmission speed still improves a lot when the system bandwidth broad.In the last example as select T _CWhen=1.4us, N=32 were 5MHz in system bandwidth, the usable frequency number was 384, was 90% o'clock as transmitting data carrier, and data transmit carrier number and are chosen as 396.At this moment QPSK peak transfer rate (16 sign indicating numbers) reaches 109.84Mbps, disturbs 8 less sign indicating numbers as selecting, and its transmission rate also reaches 54.92Mbps, and spectrum utilization efficiency reaches 10.9.

In the scope of the transmission rate that given hope reaches and the availability of frequency spectrum, use bigger N to be advisable, because the interference between the big time-frequency code of N will reduce relatively.

Claims (10)

1, a kind of multi-code OFDM transmission method may further comprise the steps

1) the OFDM symbol that multichannel is contained primary data information (pdi) carries out serial to parallel conversion, so that obtain multichannel OFDM branch data;

2) utilization waits one group of associated code that waits as spreading code in the correlated series, and described multichannel OFDM branch data is carried out band spectrum modulation processing respectively;

3) the described multichannel OFDM branch data through band spectrum modulation processing is added the Cyclic Prefix symbol respectively, launch by radio system through the combination back then.

2, multi-code OFDM transmission method according to claim 1, wherein, associated code such as described a group is the group code that all yards cross-correlation coefficient all equates.

3, multi-code OFDM transmission method according to claim 2, wherein, the minimum unit sign indicating number of described associated code such as grade is 4 bit code, comprises the described minimum unit sign indicating number of two classes,

First kind minimum unit sign indicating number comprises: 1110; 1101; 1011; 1000

The second class minimum unit sign indicating number comprises: 1111; 1010; 1100; 1001.

4, multi-code OFDM transmission method according to claim 3, wherein,

Utilize complementary converter that first kind minimum unit sign indicating number is carried out complementary conversion, obtain the relevant mutual-complementing code of four corresponding first kind minimum units: 1011; 1000; 1110; 1101;

Utilize complementary converter that the second class minimum unit sign indicating number is carried out complementary conversion, obtain the relevant mutual-complementing code of four second corresponding class minimum units: 1010; 1111; 1001; 1100.

5, multi-code OFDM transmission method according to claim 3, wherein,

Utilize combiner that described four first kind minimum unit sign indicating numbers are carried out combination in any, form code length and be the relevant spreading codes such as the first kind of 4 integral multiple; Perhaps

Utilize combiner that described four second class minimum unit sign indicating numbers are carried out combination in any, form code length and be the relevant spreading codes such as second class of 4 integral multiple.

6, multi-code OFDM transmission method according to claim 5, wherein, described combination in any comprises: a minimum unit sign indicating number is added up; A minimum unit sign indicating number and its radix-minus-one complement are added up; And different minimum unit sign indicating numbers added up.

7, multi-code OFDM transmission method according to claim 5, wherein,

Utilize combiner that the relevant mutual-complementing code of described four first kind minimum units is carried out combination in any, form code length and be the relevant complementary spreading codes such as the first kind of 4 integral multiple; Perhaps

Utilize combiner that the relevant mutual-complementing code of described four second class minimum units is carried out combination in any, form code length and be the relevant complementary spreading codes such as second class of 4 integral multiple.

8, multi-code OFDM transmission method according to claim 7, wherein, described combination in any comprises: the relevant mutual-complementing code of a minimum unit is added up; The relevant mutual-complementing code of a minimum unit and its radix-minus-one complement are added up; And the relevant mutual-complementing code of of a sort different minimum units added up.

9, multi-code OFDM transmission method according to claim 7, the wherein said associated code that waits as spreading code forms by one of following steps:

Utilize combiner to make up relevant spreading codes such as the described first kind and relevant complementary spreading codes such as the first kind; Perhaps

Utilize combiner to make up relevant spreading codes such as described second class and relevant complementary spreading codes such as second class.

10, a kind of many yards 0FDM transmission equipments comprise:

The OFDM symbol that multichannel is contained primary data information (pdi) carries out serial to parallel conversion so that obtain the device of multichannel OFDM branch data;

In the correlated serieses such as utilization the one group associated code that waits as spreading code carries out the device of band spectrum modulation processing respectively to described multichannel OFDM branch data;

Described multichannel OFDM branch data through band spectrum modulation processing is added the Cyclic Prefix symbol respectively, then the device of after making up, launching by radio system.

Images