Title of Invention

EMISSION FOR CDMA COMMUNICATIONS SYSTEMS ON THE MIMO CHANNEL

Abstract

The invention relates to a transmission method for multiple users wishing to transmit digital data on a frequency selective channel by means of multiple transmitting and recieving antennas is characterised in that it uses encoded interleaved data (d[n]) for carrying out a demultiplexing(105) on K channels, wherein k is strictly greater than the numbers T of transmitting antennas, the modulation(107) of the thus demultiplexed data, an inner linear coding (108) defined by a generator matrix (W,Wn) having N/K dimensions, wherein N is strictly greater than T and the inner coding is applied on K-dimensioned vectors of modulated data. A transmitting system for carrying out said method is also disclosed.

Full Text

FORM 2 THE PATENTS ACT, 1970 (39 of 1970) & The Patents Rules, 2003 COMPLETE SPECIFICATION (See section 10, rule 13) "EMISSION FOR CDMA COMMUNICATIONS SYSTEMS ON THE MEMO CHANNEL France Telecom, a French Limited Company of 6 Place d'Alleray-75015, Paris-France. The following specification particularly describes the invention and the manner in which it is to be performed. 'A- EMISSION FOR CDMA COMMUNICATIONS SYSTEMS ON THE MIMO CHANNEL GENERAL TECHNICAL FIELD 5 The present invention relates to the field of digital communications. It concerns how to route digital data on a frequency-selective MIMO channel with a view to maximizing spectral efficiency. 10 GENERAL DESCRIPTION OF THE PRIOR ART Sending With the advent of antenna technologies, communications models based on the various multiple 15 access techniques (TDMA (time division multiple access), CDMA (code division multiple access), and OFDMA (orthogonal frequency division multiple access)) are systematically reviewed and extended to encompass MIMO channels. With the aim of improving spectral efficiency, 20 systems must additionally be studied under overload conditions, i.e. with a number of users chosen to be greater than the available resource (in terms of separate time slots or frequency slots and/or orthogonal spreading codes) at the same time as preserving the possibility of 25 separating them on detection (see for example reference [1]). [1] H. Sari, F. Vanhaverbeke, M. Moeneclaey, "Channel Overloading in Multiuser and Single User Communications", 30 ref. Recent theoretical work has explored the potential of multiple antennas for sending (T antennas) and receiving (R antennas) and highlight a potential 35 considerable increase in capacity. Of the space-time coding schemes adapted to MIMO transmission, only the BLAST approach [2] (see below), for which the capacity -3- increases in a linear fashion with mm.(T,R) (ergodic case) is able to support remarkably high bit rates. [2] G.J. Foschini, "Layered Space-Time Architecture for 5 Wireless Communication in a Fading Environment When Using Multiple Antennas", Bell Labs Tech. J., vol.2, no.2, pp. 41-59, 1996. Referring to Figure 1, the BLAST concept on sending 10 100, amounting to simple spatial demultiplexing of the data over the various sending layers (V-BLAST), authorizes any type of modulation scheme (single-carrier, multicarrier, with or without spectral spreading) and may be combined with coding of the external channel 300 15 followed by bit interleaving (STBICM interleaved coded modulation). Accordingly, a STBICM-type sending model employing specific scrambling codes on each layer is disclosed in document [3] for example (see below). A formal analogy 20 may be made with MC-CDMA when the spreading is effected in the frequency domain. Reception is referenced 200 in Figure 1. [3] D.L. Shilling, "Efficient Shadow Reduction Antenna 25 System for Spread Spectrum", US 6 128 330, Oct. 2000. SUMMARY OF THE INVENTION The first aspect of the invention proposes a sending method according to any one of claims 1 to 21. 30 A second aspect of the invention proposes a sending system according to any one of claims 22 to 25. An object of the present invention is to propose a space-time coding scheme based on a combination of simple mechanisms and techniques with a view to increasing 35 spectral efficiency and combating the harmful effects of the frequency-selective MIMO transmission channel with T send antennas and R receive antennas, on the general hypothesis of the absence on sending of CSI (i.e. information as to the state of the channel). Main objectives of the present invention are, furthermore: 5 • a send space-time coding scheme comprising a channel corrector coding and external interleaving method; • a send space-time coding scheme based on demultiplexing coded data to produce K > T separate 10 streams of symbolic coded interleaved data; • a send space-time coding scheme based on space-time or space-frequency internal linear coding (or spreading) by means of a resource limited in orthogonal codes of length N or N/T, these codes being re-used so 15 that operation of the system beyond saturation may be envisaged with the aim of increasing spectrum efficiency; • multiplexing of data coded, modulated, spread in space and in time over T separate send antennas; • a sending space-time coding scheme the spectral 20 efficiency whereof may be adapted very closely to propagation conditions. In particular, the invention proposes a sending system comprising: • means for guaranteeing temporal decorrelation of 25 samples of noise affecting the chips when reforming on reception the multiple access model with K users in the assumed absence of MAI+ISI, said means consisting in internal linear periodic coding followed by chip interleaving or internal linear aperiodic coding, before 30 transmission over the MIMO channel. Note that although chip interleaving is not necessary for internal linear aperiodic coding, it remains an option. DESCRIPTION OF THE FIGURES 35 Other features and advantages of the invention will emerge further from the following description, which is purely illustrative and non-limiting and must be read with reference to the appended drawings in which: • Figure 1 shows the concept of the VBLAST technique applied to a frequency-selective MIMO channel; 5 • Figure 2 shows a generic method of external channel coding of digital information, interleaving, and demultiplexing into K streams; • Figure 3 shows a process of space-time (or space-frequency) internal linear coding (or spreading) 10 followed by multiplexing to T send antennas; • Figure 4 shows a space-time (or space-frequency) internal linear coding (or spreading) method followed by multiplexing onto a single channel, chip level interleaving, and then demultiplexing onto the T send 15 antennas; • Figure 5 shows a generic method of external channel coding of digital information, interleaving, first demultiplexing into T streams (space demultiplexing) followed by second demultiplexing into U 20 streams (code demultiplexing); • Figure 6 shows a time (or frequency) method of internal linear coding (or spreading) and of independent multiplexing at each antenna, compatible with the UMTS HSDPA mode; 25 • Figure 7 shows a method of time (or frequency) internal linear coding (or spreading) and of independent multiplexing at each antenna, followed by multiplexing into a single stream, interleaving at chip level, and then demultiplexing onto the T send antennas, compatible 30 with the UMTS HSDPA mode; • Figure 8 shows the flat ergodic or block fading equivalent channel obtained by decomposition of the frequency-selective MIMO in the Fourier base, routinely used for modeling multicarrier modulation. 35 DESCRIPTION OF PREFERRED EMBODIMENTS OF THE PRESENT INVENTION 1. General structure of the sender 5 The present invention describes a modulation/coding scheme of great spectral efficiency and high adaptability capacity relying on the use of spread spectrum modulation and on the use of multiple send and receive antennas. The solution proposed is pertinent assuming no knowledge 10 of the send channel (no CSI) and a perfect knowledge of the receive channel (CSI). 1.1 External coding of data The usable digital data is collected and grouped 15 into a message m of K0 bits constituting the source 101 of the send digital data. To any message m, a linear external code CD, with N0xK0 generator matrix G0 and constructed on F2 assigns at 102 a code word v of length N0 bits defined by the matrix equation: 20 v = G0m The external coding yield is: P=K0/N0 The length N0 of the code words is linked to the various parameters of the system by the equation: 25 N0=KxLxq in which K designates the total number of users, L the length of the packets (in symbol times), and q the number of bits per modulation symbol. The code may be of any type, for example a convolutional code, a turbo code, an 30 LDPC code, etc. In a multiple access type configuration, the message m consists in a plurality of multiplex messages from different sources. Coding is effected independently of each component message. The code word v results from the concatenation of the various code words 35 produced. 1.2 Bit interleaving After multiplexing 103, the code word v is sent to an interleaver 104 (operating at the bit level and, where appropriate, having a particular structure). In a 5 multiple access type configuration, interleaving is effected piece by piece on the various code words placed one after the other. The output of this interleaver 104 is parceled into KL sets of g bits called integers. 10 1.3 Demultiplexing and modulation The integer stream is subjected to a process 105 of demultiplexing onto K separate channels, K being strictly greater than T, and chosen arbitrarily. The output from this operation is a KxL matrix D of integers. The L 15 columns of d[n] n = 0,...,L-l of this matrix D have the following structure: d[n] = [d1 [n]T d2 [n]T - dK[n]T]TeF2gk in which the component integers dk[n] k = \,...,K are themselves structured as follows: 20 dk[n] = [dk1[n] dk2[n] ••• dkq[n]]TEF2q Referring to Figure 3, the integers dk[n] of the matrix D are then individually modulated (107) into modulated data, more particularly here into complex symbols sk[n] of a constellation 3cD with Q = 2q elements 25 via a modulation table //:F29h->3. This operation transforms the integer matrix D into a KxL complex matrix S the L columns s[«] n = 0,...,L-l whereof are structured as follows: s[n]D//(d[n]) = [s1[w] s2[n] ••• sK[n]T&3K 30 It is useful to specify the following converse relationships: u-1(s[n])n d[n] u-1(sk [n])U dk [n] uj-1(sk[n])Q dkJ[n] 1.4 Internal linear coding (or spreading) strategies 3 5 There are several options for the definition of the generator matrix W defining internal linear coding over the body of the complexes (or spreading), which may impact on the structure of the sender and on the characteristics of the linear front-ends on reception: 5 • Periodic spreading (or internal coding) where W is re-used in each symbol time. To guarantee temporal decorrelation of samples of noise affecting the chips when reforming the multiple access system after equalization, chip interleaving must be applied before 10 transmission on the MIMO channel; or • Aperiodic spreading (or internal coding) in which W depends explicitly on the symbol time. Aperiodic spreading guarantees temporal decorrelation of samples of noise affecting the chips when the multiple access system 15 is reformed after equalization. Chip interleaving is no longer necessary but remains an option. Moreover, the spreading may be space-time spreading (or space-frequency spreading) when it is performed in one block for all of the antennas or merely temporal (or 20 frequency) spreading if it is effected independently for each antenna. Four main types of internal linear code will therefore be described below: • aperiodic space-time (or space-frequency) internal 25 linear coding (or spreading); • aperiodic temporal (or frequency) internal linear coding (or spreading); • periodic space-time (or space-frequency) internal linear coding (or spreading; 30 • periodic time (or frequency) internal linear coding (or spreading). 1.5 Aperiodic space-time (or space-frequency) spreading (or internal linear coding) without chip interleaving 35 Referring to Figure 3, aperiodic space-time (space-frequency) spreading is assumed here. The space-time (space-frequency) spreading is effected for -9- each matrix S by means of a NxK internal coding matrix Wn where: N = TxSF SF(=n The internal coding yield (or load) of the system is the 5 ratio: K a = — N Multiplying the symbol vector s[«] by the internal coding matrix W produces a vector: z[n]Q Wn s[n] = [z1[n] z2[n) .- zN[n]]TeUN 10 The relationship may also be written at the matrix level: ZDW„SeDNxL The chip vectors z„[«] n = 0,...,L-\ are multiplexed into T separate chip streams (one for each send antenna). The 15 effect of this operation is to transform the NxL chip matrix Z: Z = [z[0] z[l] ••• z[L-l]]eDNxL into a TxLSF chip matrix X: X = [x[0] x[l] ••• x[LSF-l]]^Ur^ 20 the columns x[/] l = 0,---,LSF-l whereof constitute the inputs of the MIMO channel: x[/] = [*,[/] x2[l] ■■■ xT[l]]TeDT N orthogonal codes of length N are available for constructing the internal coding matrix W„ . The system 25 is overloaded as soon as: K>N Consider the result of the polynomial division of K by N: K=AN+B 30 The K users are therefore divided into A saturated groups of N users and one unsaturated group of B users. We set: -10- ^N °h,N ^,1 OK, D NxN ^N,N ~ «\,2 °h,2 coK, (Q„ "N,\ WN,2 WN,N _ an NxN matrix representing a unit group of spreading codes formed of the N orthogonal codes (Hadamard matrix for example) that by construction satisfies the equation: 5. and **N,N**N,N = 1 "%, *U - • %/ 'Vs W2h ViM ■ • ^. ^NM °>NA " • *VV. eD NxB a truncated version, formed of B columns drawn at random in QNN • 10. Likewise: ^JV,£ JV.B _ The diagonal NxN matrix, the diagonal elements whereof are normalized QPSK chips drawn pseudo-randomly, is called the scrambling matrix for the saturated group 15. of users i = l,...,A and written: si .(«.'•) y(".0 _ **N,N - b2 NxN ?N Similarly, the NxN scrambling matrix for the unsaturated group of B users is called: .(».«) £ ^N,N ~ (n,B) eD NxN ?N 20. This scrambling matrix will therefore make it possible to guarantee decorrelation of the chip streams sent over the various antennas (by means of the scrambling codes) when it is applied to the spreading matrix to form the internal coding matrix Wn as follows: - II- Q •N,N Q w„=[x£ ?(n,A) JN,N V(»,«)l •N,N eD NxK a •N,B It may always be written in the form: ,(«) W = 2,1 w w, 1,2 w. ,(") 2,2 W ,(») 2,A" w. GD WxA- w W w W,l ,(«) JV.2 ,(») 5. 1.6 Independent aperiodic time (or frequency) spreading for each send antenna (re-use principle), without chip interleaving In this other variant of the invention, described with reference to Figure 6, compatible with the HSDPA 10 mode of the UMTS standard, there are SF orthogonal codes of length SF . The parameter N is always a multiple of T. N = TxSF SFED The SF codes available are re-used for each send antenna (this is the code re-use principle). The 15 spreading, effected independently for each antenna, is time spreading or frequency spreading. This imposes that K is also a multiple of T: K = TxU C/eD U This non-limiting condition according to the 20. invention then leads to a new expression for the internal coding yield (load): a = The internal coding matrix Wn has a block diagonal structure: 25. "W„(1) 0 NxK w„(2) €=□ w = (T) w: the block Wn(t) of the internal coding matrix being associated with the antenna t with dimension SFxU . Referring to Figure 6, the integer vector d[n] (demultiplexed at 105, after being coded at 102 and 5. interleaved at 104) sent at the time n has the following particular structure: d[n] = [d(1)[n]T d(2)[n]T ... d(r)nT]Te/f in which the symbol vectors d(,)[«] t = \,...,T are themselves eFf defined as follows: 10 d(t) [n] =[d1(t) [n]T d« [w]T - 4}[n]J Referring to Figure 6, the modulation 107 of this multiplexed data d[n] yields a vector of symbols sent at the time n having the following particular structure: S[n] = [s(1)[n]T s(2)[/if - siT)[n]TJ defined as follows: s(/)[»] = [51(')H sf[n] ••• s^[n]J GUU The multiplication 108 of the symbol vector s[n] by the internal coding matrix WM produces the vector: 20 z[»]DWfls[«] which also has a particular structure: z[w] = [z(1)[/i]T z(2)[»]T ••• ziT)[n]rJeUN in which the chip vectors z(,)[«] t = \,...,T are themselves defined as follows: 25 z(,)[»]DW„(')s(')H = [z,(')[/i] zf[n] ••• z^[n]]\us^ For each antenna t, the chip vector z(,)[«] is then multiplexed at 109-t onto the send antenna t that is associated with it. It will be noted that, in this sending variant, the 30 recovery of the spatial diversity is effected via the external code G0 (at 102) and external bit interleaving (at 104) . The overload capacity, known to increase with the length of the spreading codes, is lower. -13- 10 15 The overload conditions and the explicit construction of the matrix Wn may be explained as follows. The system is overloaded as soon as: TxU>SF This does not necessarily imply U>SF (i.e. there is not necessarily an overload at each antenna). When U>SF, the various antennas are overloaded individually. The condition TxU>SF is then trivial to verify and the system with multiple antennas is qualified as entirely overloaded. Consider the result of the polynomial division of U by SF : U = ASF+B The U users associated with each of the send antennas are thus divided into A saturated groups of SF users and one unsaturated group of B users. We set: ^ s = eD op-X-bp- CO, CO, CO, 20 Sr,2 Lip ,Jr sF,an SFxSF matrix representing a unitary group of spreading codes formed of the SF orthogonal codes (Hadamard matrix for example) that by construction satisfy the equation: HMO C &BO O ~~ M. ■V ,of JF ,Of Ofr,Op Ofp,Op and ^F,B ■D SFxB coCO) ,(') ,(') JF'K2 4", 25 a truncated version, specific to the antenna t, formed of B columns drawn a random in Q, ,, . Likewise: ^F,B^F,B = *■ 30 An SFxSp diagonal matrix, the diagonal elements of which are normalized QPSK chips drawn randomly, is called the scrambling matrix for the saturated group of users i = l,...,A and written: si Op- ,0/r £ («,',o (n,',o g [-] SFxSF Similarly, the SFxSF matrix 5 7 .(n,l,B) Op'X.dp- r(",t,B) fesF is called the scrambling matrix for the unsaturated group associated with the antenna t. This scrambling matrix associated with the block ( WB(0 ) will therefore make it possible to guarantee decorrelation of the chip streams sent over the antenna t (by means of the scrambling codes), when it is applied to the spreading matrix to form the block w„(" of the internal coding matrix Wn as follows: w,w=D£g sF,sF aF^F J ^sF,s D SFxU tyF,B It may always be written in the form: w. «.') 1,1 1,2 w. W XV. W- W- w: c) _ 2,1 2,2 2,U SFxC/ ,M ,(».') w: w. W, »,') VSF,1 "SF,2 SF,U Note: For obvious reasons of simplicity, this section covers a situation in which the internal coding matrix Wn is made up of blocks w„(,) (te [1 ;T] ) with exactly the same dimensions as each other (SFXU).This case may be extended to more general cases in which the internal coding matrix Wn is made up of blocks *]£' &£ with dimensions that differ from each other, and in particular the most general case in which the block w„(,> has dimensions SFxUt, Ut being the number of potential channels of the antenna t, which is therefore not 5 necessarily the same from one antenna to another. The matrix Wn is therefore of dimension NXK with T K=IU . The sending method could then be adapted to this variant. 10 1.7 Periodic spreading Here the processing is identical to that of section 1.5 or 1.6, except that here the generator matrix is applied periodically in time and expressed as follows: 15 V«, W„=W 1.8 Chip interleaving Referring to Figures 4 and 7, linear internal coding (or spreading) of any kind corresponding to one of the 20 strategies described in sections 1.5 to 1.7 is assumed here, but coupled to chip interleaving 108. After chip spreading 108, the chip vectors z[n] n = 0,...,L-l are multiplexed at 109 into a single stream of chips. The chip stream then drives an interleaver 110, 25 the output whereof is demultiplexed at 111 into T separate chip streams, one for each send antenna. The effect of this operation is to transform the NxL chip matrix Z: Z = [z[0] z[l] ••• z[l-l]]eDM 30 into a TxLSF chip matrix X: X = [x[0] x[l] ••• x[LSF-l]\znT*LS? whereof the columns x[/] l = 0,---,LSF-l constitute the inputs of the MIMO channel: x [/] = [*,[/] x2[l] ■■■ x7.[/]]TeDr 35 1.9 Spectral efficiency The sending method fits naturally into the general class of space-time codes. The spectral efficiency of the system (in bits per use of the channel), assuming a 5 limited band ideal Nyquist filter, is equal to: r/ = Txp0xqxa In practice, the send shaping filter has a non-null overflow factor (roll-off) 8. At the receiver, a filter matched to the send filter is used for all the receive 10 antennas. It is assumed that the channel estimation and timing and carrier synchronization functions are implemented so that the coefficients of the impulse response of the channel are regularly spaced by an amount equal to the chip time (channel equivalent in the 15 discrete baseband to the chip time). This hypothesis is legitimate, the Shannon sampling theorem imposing sampling at the rate (\ + e)/Tc which may be approximated by \ITC when e is small. Direct generalization is possible for expressions 20 given below for a sampling rate equal to a multiple of \ITC. 2. Channel model Transmission is effected on a frequency-selective 25 B-block channel with multiple inputs and outputs (MIMO): HD{H(1),H(2),...,H(B)} The channel H(A) is assumed constant over Lx chips with the convention: LxSF=BxLx 5eD 30 The chip matrix X may be segmented into B separate TxLx chip matrices X(1),...,X(B) (padded on the right and left with physical zeros or guard times if necessary), each matrix X(A) seeing the channel H(A) . The extreme cases of the B-block model are as 35 follows: P6 B = \ and Lx = LSF => Ls = L quasi - static model B = LSF and Lx = 1 => Ls -1 ergodic (chip) model A renumbering of the chips is applied within each block. 5 For any block index b, the discrete time baseband equivalent channel model (chip timing) is used to write the vector y(6)[/]eDs received at the chip time 1 in the form: y«[/] = XH«[/-p]+vH/] 10 where P is the constraint length of the channel (in chips), x^f/JeD7" is the complex vector of T chips sent at the chip time 1, H^eD^ is the matrix coefficient indexed p of the impulse response of the block MIMO channel indexed b and v((l)[/]eD'i is the complex additive 15 noise vector. The complex additive noise vectors v(ft)[/] are assumed to be independent and identically distributed in accordance with an R-dimensional Gaussian law of circular symmetry with zero mean and covariance matrix o2l. The P coefficients of the impulse response are RXT 2 0 complex matrices, the inputs of which are identically distributed independent Gaussian inputs, with zero mean and with a covariance matrix satisfying the global power normalization constraint: diag{fx>Htj =71 25 in the case of a system with power equally distributed between the send antennas. Given these hypotheses, the eigen values of the correlation matrices of the coefficients of the MIMO channel conform to a Wishart distribution. It is emphasized that equal distribution 30 of the power to the send antennas is a legitimate power allocation policy in the case of an absence of knowledge of the sending channel (no CSI). 3. Multipath MIMO channel single-carrier transmission (HSDPA) It is assumed here that the bit rate is very high and that the Doppler frequency of the channel is low, so 5 that LXU SF . For the HSDPA mode of the UMTS standard, the channel is quasi-static, i.e. B = 1. 4. Multipath MIMO channel multicarrier transmission (MC-CDMA) 10 Here the internal linear coding 108 is space-frequency coding or frequency coding. With reference to Figure 8, it is well known to the person skilled in the art that the introduction of a send IFFT at 120 and a receive FFT at 220 yields (ignoring 15 interleaving) an equivalent channel that is not frequency-selective (channel modeled by a circulating matrix using cyclic prefixes, then rendered diagonal in the Fourier base). Accordingly, each carrier sees a flat MIMO equivalent channel. Using the formalism previously 20 described, the channel after FFT may be seen as a non-selective B-block channel (P = 1, M = 0). Reception in accordance with the invention refers not only to the method for implementing it but also to the system for executing it. -11' WE CLAIM: 1. A sending method for multiple users requiring transmission of digital data over a frequency-selective channel with a plurality of send antennas and a plurality of receive antennas, said digital data comprising coded and interleaved data (d[n]), the method comprising the steps of: demultiplexing (105) the coded and interleaved data into K channels, where K is strictly greater than number of send antennas (T); modulating (107) the demultiplexed data into K-dimensional vectors of modulated data; and applying internal linear coding (108) defined by an NxK generator matrix (W, Wn) to the K-dimensional vectors of the modulated data, wherein N is strictly greater thanT. 2. The method as claimed in claim 1, wherein a yield K/N of the internal linear coding is strictly greater than 1. 3. The method according to either of the preceding claims, wherein said generator matrix (W, Wn) is constructed from N orthogonal spreading codes of length N, producing a spreading factor equal to N. 4. The method as claimed in claim 3, wherein the spreading codes are re-used several times in the generator matrix (W, Wn) to form therein a plurality of groups of spreading codes such that the spreading codes of each group of spreading codes are mutually orthogonal. 5. The method as claimed in claim 4, wherein said generator matrix (W, Wn) is further constructed from a plurality of scrambling codes (E) superposed on the spreading codes so that each group of spreading codes is assigned its own scrambling codes. 6. The method as claimed in claim I or claim 2, wherein the linear internal coding is-for the antenna t is applied to a modulated data vector T of dimension Ut strictly greater than 1, with K=? Ut, said generator matrix (W, Wn) being a diagonal block matrix, the number of blocks being equal to the number T of send antennas, and the block associated with the antenna t being of dimension (N/T)XUt 7. The method as claimed in any of the preceding claim, wherein the dimension Ut of the block associated with the antenna t is the same as that of each of the other blocks of the generator matrix (W, Wn), Ut being denoted U and each block being of dimension (N/T) XUt. 8. The method as claimed in claim 6 or claim 7, wherein each of said blocks of the generator matrix (W, Wn) is constructed from N/T orthogonal spreading codes of length N/T, producing a spreading factor N/T. 9. The method as claimed in claims 6 to 8, wherein the blocks are constructed from the same orthogonal spreading codes. 10. The method as claimed in anyone of claims 6 to 9, wherein the generator matrix is further constructed from a plurality of scrambling codes (E) superposed on the spreading codes so that each of said blocks of the spreading matrix is assigned its own scrambling code of the plurality of scrambling codes. 11. The method as claimed in anyone of claims 6 to 10, wherein K is strictly greater than N/T. 12. The method as claimed in anyone of claims 6 to 9, wherein Ut is strictly greater than N/T regardless of the value oft, 13. The method as claimed in claim 12, wherein each of said blocks is constructed from a plurality of groups of spreading codes, each group of spreading codes being constructed from N/T orthogonal codes of length N/T, producing a spreading factor N/T, the N/T spreading codes being re-used several times per block to form said plurality of groups of spreading codes per block, so that the spreading codes of -each group of spreading-codes-are-mutually-orthogonal. 14. The method as claimed in claim 13, wherein the generator matrix (W, Wn) is further constructed from a plurality of scrambling codes (E) superposed on the spreading codes so that each group of spreading codes is assigned its own scrambling code, said scrambling codes for each group and each block being different from each other. 15. The sending method as claimed in any preceding claim, wherein the method further comprises, after the internal linear coding (108): (a) multiplexing (109) data resulting from the internal linear coding to form multiplexed data; (b) interleaving (110) the multiplexed data to form interleaved data; and (c) demultiplexing (111) the interleaved data to distribute the interleaved data over the send antennas (T). 16. A sending method according to anyone of claims 1 to 14, characterized in that it further comprises, after the internal linear coding (108), multiplexing (111) to distribute the data over the send antennas(T), 17. The sending method as claimed in any preceding claim, wherein the internal linear coding (108) is applied to the K-dimensional vectors of the modulated data periodically in time. 18. The method as claimed in anyone of claims 1 to 16, wherein the internal linear coding (108) is applied to K-dimensional vectors of the modulated data aperiodically in time. 19. The method as claimed in any preceding claim, characterized in that it further comprises, before said demultiplexing (105), at least one external coding (102) of the digital data coming from one or more users and interleaving (104) to form said coded -and-interleaved-data(d[n]). 20. The sending method as claimed in any preceding claim, wherein the internal linear coding is effected in the frequency domain and the transmission is of the multicarrier type. 21. The sending method as claimed in anyone of claims 1 to 19, wherein the internal linear coding is effected in the time domain and the transmission is of the single-carrier type. 22. A sending system for multiple users requiring transmission digital data over a frequency-selective channel with a plurality of send antennas and a plurality of receive antennas, the sending system comprises: a demultiplexer (105) configured to demultiplex coded and interleaved data (d[n]) on K channels, where K is strictly greater than the number T of the plurality of send antennas; a modulator (107) configured to modulate the output data of the demultiplexer; an internal linear encoder (108) adapted to code by means of an NxK generator matrix (W, Wn) K-dimensional vectors of data at the output of the modulator, where N is strictly greater than T, and T send antennas. 23. The system as claimed in claim 22, further comprises: a multiplexer (109) configured to multiplex data coded by said internal encoder (108) to form multiplexed data; an interleaver (110) configured to interleave the multiplexed data to form interleaved data; and a demultiplexer (111) for distributing the interleaved data over the T send antennas. .24, The system as claimed in claim 22,wherein it further comprises a multiplexer (111) configured to multiplex data coded by said internal liner encoder(108) to distribute the data coded by said internal linear encoder over the send antennas(T). 25. The system as claimed in anyone of claims 22 to 24, wherein it further comprises, upstreani of the demultiplexer (105): an encoder (102) configured to encode the digital data coming from one or more users to form coded digital data; a bit level iiiterleaver (104) configured to interleave the coded digital data to form said coded and interleaved data. ABSTRACT "EMISSION FOR CDMA COMMUNICATIONS SYSTEMS ON THE MIMO CHANNEL" The invention relates to a transmission method for multiple users wishing to transmit digital data on a frequency selective channel by means of multiple transmitting and receiving antennas is characterised in that it uses encoded interleaved data(d[n]) for carrying out a demultiplexing (105) on K channels, wherein k is strictly greater than the numbers T of transmitting antennas, the modulation (107) of the thus demultiplexed data, an inner linear coding (108) defined by a generator matrix (W,Wn) having N/K dimensions, wherein N is strictly greater than T and the inner coding is applied on K-dimensioned vectors of modulated data. A transmitting system for carrying out said method is also disclosed.

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1305-MUMNP-2006-CLAIMS(MARKED COPY)-(12-7-2012).pdf

1305-mumnp-2006-claims.doc

1305-mumnp-2006-claims.pdf

1305-mumnp-2006-correspondance-received.pdf

1305-MUMNP-2006-CORRESPONDECE(03-11-2009).pdf

1305-MUMNP-2006-CORRESPONDENCE(12-7-2012).pdf

1305-mumnp-2006-correspondence(24-3-2008).pdf

1305-MUMNP-2006-CORRESPONDENCE(4-9-2012).pdf

1305-mumnp-2006-description (complete).pdf

1305-mumnp-2006-drawing(7-11-2006).pdf

1305-mumnp-2006-drawings.pdf

1305-mumnp-2006-form 1(12-9-2007).pdf

1305-MUMNP-2006-FORM 1(4-9-2012).pdf

1305-mumnp-2006-form 13(03-11-2009).pdf

1305-MUMNP-2006-FORM 13(12-7-2012).pdf

1305-MUMNP-2006-FORM 13(4-9-2012).pdf

1305-mumnp-2006-form 18(24-3-2008).pdf

1305-mumnp-2006-form 2(title page)-(7-11-2006).pdf

1305-mumnp-2006-form 26(12-9-2007).pdf

1305-MUMNP-2006-FORM 3(10-4-2012).pdf

1305-mumnp-2006-form 3(10-7-2007).pdf

1305-mumnp-2006-form-1.pdf

1305-mumnp-2006-form-13.pdf

1305-mumnp-2006-form-2.doc

1305-mumnp-2006-form-2.pdf

1305-mumnp-2006-form-3.pdf

1305-mumnp-2006-form-5.pdf

1305-mumnp-2006-form-pct-ib-301.pdf

1305-mumnp-2006-form-pct-ib-304.pdf

1305-mumnp-2006-form-pct-isa-210.pdf

1305-mumnp-2006-form-pct-isa-220.pdf

1305-mumnp-2006-form-pct-isa-237.pdf

1305-MUMNP-2006-JAPANESE DOCUMENT(10-4-2012).pdf

1305-MUMNP-2006-KOREA DOCUMENT(10-4-2012).pdf

1305-MUMNP-2006-PETITION UNDER RULE 137(10-4-2012).pdf

1305-MUMNP-2006-REPLY TO EXAMINATION REPORT(10-4-2012).pdf

1305-MUMNP-2006-SPECIFICATION(AMENDED)-(03-11-2009).pdf

1305-MUMNP-2006-US DOCUMENT(10-4-2012).pdf

1305-mumnp-2006-wo international publication report(7-11-2006).pdf

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