Method to increase the bit rate in a communications system

• US 20030128770A1
• Filed: 08/09/2002
• Published: 07/10/2003
• Est. Priority Date: 08/10/2001
• Status: Active Grant

• Current Assignee: Thales SA
• Original Assignee: Thales SA
• Inventors: Morgand, Philippe, Chenu-Tournier, Marc
• Granted Patent: US 7,149,255 B2
• Time in Patent Office: Days
• US Class Current: 375/267
• CPC Class Codes: H04B 7/04 using two or more spaced independent antennas
• CPC Class Codes: H04B 7/0851 using training sequences or error signal minimizing error signal H04B7/0854
• CPC Class Codes: H04B 7/0854 using error minimizing algorithms, e.g. minimum mean squared error [MMSE], "cross-correlation" or matrix inversion

Abstract

Disclosed is a method and a device to increase the bit rate in a communications system comprising N transmitters (2_N) and M receivers (3_M), with M greater than or equal to N. The method comprises the following steps.

a) simultaneously sending different messages on several of the N (2_N) transmitters,

b) simultaneously receiving the superimposition of the messages sent during the step a) on several of the M (3_M) receivers or reception sensors,

c) estimating the characteristics of the transmission channel for each pair constituted by a transmission sensor and a receiver sensor,

d) jointly estimating all or at least the majority of the messages received in taking account of the signals as well as the characteristics of the transmission channel.

Application to GSM signals and to systems of unicast transmission and multicast transmission, namely multipoint-to-point and multipoint-to-multipoint transmission.

Claims

1. A method to increase the bit rate in a communications system comprising N transmitters and M receivers, with M greater than or equal to N, the structure of the data exchanged comprising no intrinsic system to differentiate between different users, wherein the method comprises at least the following steps.

a) simultaneously sending different messages on several of the N transmitters,

b) simultaneously receiving the superimposition of the messages sent during the step a) on several of the M receivers or reception sensors,

c) estimating the characteristics of the transmission channel for each pair constituted by a transmission sensor and a receiver sensor,

d) jointly estimating all or at least the majority of the messages received in taking account of the signals as well as the characteristics of the transmission channel or channels.

2. A method according to claim 1, wherein the step d) is performed, for example, with a receiver adapted to the joint estimation of the reference sequences transmitted in the signal and the propagation channels.

3. A method according to claim 2, wherein the step d) uses a linear filter minimizing the mean squared error between the output of the receiver and the real symbols of the signal received at the reception sensors

4. A method according to claim 2, wherein the step d) uses a non-linear filter minimizing the mean squared error in taking account of a “

feed forward”

filtering function and a “

feedback”

filtering function and of the vector bn of the symbols of the received signal.

5. A method according to one of the claims 1 to 4, wherein the signals are GSM signals comprising a reference sequence used for the step d).

6. A use of a method according to one of the claims 1 to 5 for a same user simultaneously transmitting several different messages or for several users each transmitting his own message.

7. A system to increase the bit rate in a transmission system comprising a number of transmitters N and a number of receivers M, the system comprising a device adapted to performing the steps of the claims 1 to 6.

8. A system according to claim 7, wherein the number M is greater than or equal to N.

9. An application of the method according to one of the claims 1 to 6 or of the system according to one of the claims 7 to 8 in systems of unicast transmission and multicast transmission, namely multipoint-to-point and multipoint-to-multipoint transmission.