Method to increase the bit rate in a communications system

• US 7,149,255 B2
• Filed: 08/09/2002
• Issued: 12/12/2006
• Est. Priority Date: 08/10/2001
• Status: Expired due to Fees

• Current Assignee: Thales SA
• Original Assignee: Thales SA
• Inventors: Morgand, Philippe, Chenu-Tournier, Marc
• Primary Examiner(s): Ghayour, Mohammed
• Assistant Examiner(s): Malek, Leila
• Application Number:
  US10/214,583
• Publication Number:
  US 20030128770A1
• Time in Patent Office: 1,586 Days
• Field of Search: 375/267, 375/260, 375/347, 375/349, 375/299, 375/259, 375/316, 370/264, 455/333
• 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.

FIGS. 2a, 2B.

Claims

1. A receiver apparatus in a communication system including N transmitters and M receivers, with M greater than or equal to N, said receiver being on of said M receivers, said receiver comprising:

a reception agent configured to simultaneously receive a superimposition of different messages sent by the N transmitters;

a demodulating agent configured to decode a signal received by the reception agent;

a channel estimating agent configured to estimate a characteristic of a transmission channel between one of said N transmitters and said receiver, and configured to jointly estimate a characteristic of the transmission channel by using information of all of the different message; and

an equalizer filter configured to minimize a mean squared error between an output of said equalizer filter and a corresponding real symbol, said equalizer filter having a feed forward filtering function and a feed back filtering function,

wherein the equalizer filter is further configured to produce a bit-error-rate (BER) of less than 10<sup>−

3</sup>, when the signal-to-noise (E_b/N₀) ratio of the signal is greater than 5 dB, and when no error correction is performed.

2. A receiver apparatus in a communication system including N transmitters and M receivers, with M greater than or equal to N, said receiver being on of said M receivers, said receiver comprising:

a reception agent configured to simultaneously receive a superimposition of different messages sent by the N transmitters;

a demodulating agent configured to decode a signal received by the reception agent;

a channel estimating agent configured to estimate a characteristic of a transmission channel between one of said N transmitters and said receiver, and configured to jointly estimate a characteristic of the transmission channel by using information of all of the different message; and

an equalizer filter configured to minimize a mean squared error between an output of said equalizer filter and a corresponding real symbol, said equalizer filter having a feed forward filtering function and a feed back filtering function,

wherein said means for equalizing is configured to minimize according to;

$E<br><br>\left[{<br><br>\left[G-B\right]<br><br>\left[\begin{array}{c}{y}_n\\ y_n^{*}\\ d_n\\ d_n^{*}\end{array}\right]-b_n<br><br>}^2\right]$

where,

G is the feed forward function,

B is the feed back function,

y_n is a symbol at input of G,

d_n is a symbol at output of B,

b_n is a real symbol.

3. A receiver apparatus in a communication system including N transmitters and M receivers, with M greater than or equal to N, said receiver being one of said M receivers, said receiver comprising:

means for receiving simultaneously a superimposition of different messages sent by the N transmitters;

means for demodulating to decode a received signal;

means for estimating a characteristic of a transmission channel between one of said N transmitters and said receiver; and

for estimating a characteristic of the transmission channel by using information of all of the different messages; and

means for equalizing to minimize a mean squared error between an output of said equalizing means and a corresponding real symbol, said equalizing means having a feed forward filtering function and a feed back filtering function,

wherein said means for equalizing includes means for minimizing according to;

$E<br><br>\left[{<br><br>\left[G-B\right]<br><br>\left[\begin{array}{c}{y}_n\\ y_n^{*}\\ d_n\\ d_n^{*}\end{array}\right]-b_n<br><br>}^2\right]$

where,

G is the feed forward function,

B is the feed back function,

y_n is a symbol at input of G,

d_n is a symbol at output of B,

b_n is a real symbol.

4. A receiving method configured to operate in a communication system including N transmitters and M receivers, with M greater than or equal to N, said receiver being one of said M receivers, said receiving method comprising:

receiving simultaneously a superimposition of different messages sent by the N transmitters;

demodulating to decode a received signal;

estimating a characteristic of a transmission channel between one of said N transmitters and said receiver;

estimating a characteristic of the transmission channel by using information of all of the different messages; and

equalizing to produce a bit-error-rate (BER) of less than 10<sup>−

3</sup>, when the signal-to-noise (E_b/N₀) ratio of the received signal is greater than 5dB and when no error correction is performed.

5. A receiving method configured to operate in a communication system including N transmitters and M receivers, with M greater than or equal to N, said receiver being one of said M receivers, said receiving method comprising:

receiving simultaneously a superimposition of different messages sent by the N transmitters;

demodulating to decode a received signal;

estimating a characteristic of a transmission channel between one of said N transmitters and said receiver;

estimating a characteristic of the transmission channel by using information of all of the different messages; and

minimizing a mean squared error between an output of an equalizing means and a corresponding real symbol, said minimizing including filtering with a feed forward filtering function and a feed back filtering function

wherein said minimizing is configured to minimize according to;

$E<br><br>\left[{<br><br>\left[G-B\right]<br><br>\left[\begin{array}{c}{y}_n\\ y_n^{*}\\ d_n\\ d_n^{*}\end{array}\right]-b_n<br><br>}^2\right]$

where,

G is the feed forward function,

B is the feed back function,

y_n is a symbol at input of G,

d_n is a symbol at output of B,

b_n is a real symbol.