Signal transmission multiple antenna method and device

• US 20050041751A1
• Filed: 12/16/2003
• Published: 02/24/2005
• Est. Priority Date: 12/16/2002
• Status: Active Grant

• Current Assignee: 3G Licensing S.A. (Fineur International S.A.)
• Original Assignee: Orange S.A.
• Inventors: Gouable, Rodolphe Le, Nir, Vincent Le, Helard, Maryline
• Granted Patent: US 7,469,015 B2
• Time in Patent Office: Days
• US Class Current: 375/267
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/0618 Space-time coding

Abstract

The invention lies within the field of wireless communications systems with several transmitting antennas, corresponding to MIMO (Multiple Input Multiple Output) systems or to MISO (Multiple Input Single Output) systems. According to the invention, the symbols to be transmitted are pre-encoded with a particular linear pre-encoding matrix then coded according to space-time block coding so as to benefit to the full from temporal and spatial diversities allowing at reception for particularly easy and efficient linear decoding.

Claims

1. Method of transmitting a signal composed of a plurality of symbols from n_e transmitting antennas, n_e being a whole number greater than or equal to 2, comprising the following stages:

pre-encode the symbols to be transmitted so as to generate, for each burst of m consecutive symbols to be transmitted, m linear combinations of symbols, m being a whole number greater than or equal to n_e, the pre-encoding consisting in applying to each vector of m consecutive symbols to be transmitted a complex orthonormal pre-encoding matrix of dimension m×

m so as to create the said m linear combinations of symbols, and

for each burst of m consecutive symbols to be transmitted, code the said m linear combinations according to a space-time coding so as to transmit one after the other blocks of q coded linear combinations, q being a whole number smaller than or equal to m, each block of q coded linear combinations being transmitted from q′

transmitting antennas, q′

being a whole number greater than or equal to q, each of the coded linear combinations of the said block of q coded linear combinations being transmitted during q″

consecutive temporal transmitting intervals specific to the said block from one of the said n_e transmitting antennas, q′

being a whole number greater than or equal to q.

2. Method according to claim 1, characterised in that q, q′

and q″

are equal to 2.

3. Method according to claim 2, characterised in that n_e is equal to 2.

4. Method according to claim 1, characterised in that the number n_e of transmitting antennas is equal to m, each coded linear combination being transmitted from a transmitting antenna specific to it.

5. Method according to any one of claims 1 to 4, characterised in that it further comprises, prior to the space-time coding stage, an interleaving stage of the said linear combinations to modify the temporal order of the latter.

6. Method according to claim 5, characterised in that the said interleaving stage is performed with the aid of on interleaving matrix of dimension m′

×

m′

, m′

being greater than or equal to m.

7. Method according to any one of the previous claims, characterised in that the pre-encoding matrix is a matrix or a combination of matrices belonging to the Special Unitary group SU(m).

8. Method according to claim 7, characterised in that the said pre-encoding matrix is the Kronecker product of a Hadamard matrix of order

$\frac{m}{k}$

by a matrix of the Special Unitary group SU(k), k being a whole number greater than or equal to 2.

9. Method according to claim 8, characterised in that the matrix of the Special Unitary group SU(2) is of type

$\begin{array}{c}[\mathrm{SU}\end{array}$

( 2 ) ] = [ a b - b * a * ] = [ ⅇ

ⅈ

⁢

 

⁢

θ

1 ⁢

cos ⁢

 

⁢

η

ⅇ

ⅈ

⁢

 

⁢

θ

2 ⁢

sin ⁢

 

⁢

η

- ⅇ

- ⅈ

⁢

 

⁢

θ

2 ⁢

sin ⁢

 

⁢

η

ⅇ

- ⅈ

⁢

 

⁢

θ

i ⁢

cos ⁢

 

⁢

η

] ⁢

 

⁢

with η

= Π

4 + k ′

⁢

Π

2 , θ

1 = - θ

2 + Π

2 + k ″

⁢

Π

⁢

 

⁢

and ⁢

 

⁢

θ

2 = θ

1 - π

2 , k ′

and k″

being integers.

10. Method of receiving a signal comprised of a plurality of symbols transmitted from n_e transmitting antennas, n_e being greater than or equal to 2, with the aid of n_r receiving antennas, n_r being a whole number greater than or equal to 1, the said symbols being transmitted according to the method of transmitting of one of the previous claims, characterised in that it consists in decoding the said m coded linear combinations received on each of the said n_r receiving antennas by applying an inverse space-time coding stage and an inverse linear pre-encoding stage to those of the said method of transmitting so as to retrieve, from the said m coded linear combinations that were transmitted, the m transmitted symbols.

11. Method of receiving according to claim 10, characterised in that:

the inverse pre-encoding stage consists in applying to the linear combinations derived from the inverse space-time coding a complex orthonormal inverse pre-encoding matrix,

the m retrieved symbols corresponding to the result of the application of a global matrix with diagonal elements proportional to a sum of diagonal elements of a diagonal matrix, and with at least several non diagonal elements proportional to a difference between diagonal elements of the diagonal matrix, the other non diagonal elements being zero, the diagonal matrix corresponding to the transformation of the m linear combinations of symbols into the linear combinations derived from the inverse space-time coding.

12. Method of receiving a signal composed of a plurality of symbols transmitted from n_e transmitting antennas, n_e being greater than or equal to 2, with the aid of n_r receiving antennas, n_r being a whole number greater than or equal to 1, the said symbols being transmitted according to the method of transmitting of claim 5 or 6, characterised in that it consists in decoding the said m coded linear combinations received on each of the said n_r receiving antennas by applying an inverse space-time coding stage, an inverse interleaving stage and an inverse linear pre-encoding stage to those of the said method of transmitting so as to retrieve, from the said m coded linear combinations that were transmitted, the transmitted symbols.

13. Method of receiving according to claim 12, characterised in that:

the inverse pre-encoding stage consists in applying to the linear combinations derived from the inverse space-time coding a complex orthonormal inverse pre-encoding matrix,

the m retrieved symbols corresponding to the result of the application of a global matrix with diagonal elements proportional to a sum of diagonal elements of a diagonal matrix, and with non diagonal elements proportional to a difference between at least two diagonal elements of the diagonal matrix, the diagonal matrix corresponding to the transformation of the m linear combinations of symbols into the linear combinations derived from the inverse space-time coding and from the inverse interleaving stage.

14. Wireless communications system characterised in that it comprises means of transmitting for implementing the method of transmitting symbols of any one of claims 1 to 9.

15. System according to claim 14, characterised in that it further comprises means for implementing the method of receiving symbols of any one of claims 10 to 13.