Combined array processing and space-time coding

• US 6,127,971 A
• Filed: 07/14/1998
• Issued: 10/03/2000
• Est. Priority Date: 07/16/1997
• Status: Expired due to Term

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Naguib, Ayman F., Calderbank, Arthur Robert
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): Mull, Fred H.
• Application Number:
  US09/114,838
• Time in Patent Office: 812 Days
• Field of Search: 342/368, 342/371, 342/372, 375/254, 375/265, 375/285, 375/296, 375/346, 375/347, 375/348, 375/349, 714/792
• US Class Current: 342/368
• CPC Class Codes: H04B 7/0669 using different channel coding between antennas space-time coding H04L1/0618
• CPC Class Codes: H04B 7/0848 Joint weighting
• CPC Class Codes: H04B 7/086 using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming
• CPC Class Codes: H04L 1/0618 Space-time coding

Abstract

Enhanced performance is realized in a wireless transmission arrangement that is subject to fading by employing a perspective that combines array signal processing with channel coding. Specifically, in accordance with our invention, antennas at the transmitter are partitioned into small groups, and individual space-time codes are used to transmit information from each group of antennas. At the receiver, an individual space-time code is decoded by a linear array processing technique that suppresses signals transmitted by other groups of antennas by treating them as interference.

Claims

1. A method for transmitting signal over n antennas comprising the steps of:

partitioning the antennas into q groups, where each group has n_k antennas, where at least for some value of k n_k ≧

2, and ##EQU10## partitioning a frame of bits into q bit-groups of B bits each, where each bit-group has B_k bits and ##EQU11## encoding each bit-group of B_k bits with coder C_k to develop n_k symbols; and

transmitting the n_k symbols over respective one of said n_k antennas.

2. The method of claim 1 where said C_k is a component code of a product code C₁ ×

C₂ ×

, . . . , ×

C_q.

3. The method of claim 1 where said C_k is a trellis code.

4. A method for decoding signals received over m receiving antennas comprising the steps of:

receiving a signal at each of the receiving antenna,

partitioning the m receiving antennas into q groups,

decoding the signals received by the antennas of a group k with code C_k, where codes C₁, C₂, . . . ,C_q for component codes of a product code C₁ ×

C₂ ×

, . . . , ×

C_q, while suppressing signals from other component codes.

5. The method of claim 4 where the signal received at each of the receiving antennas corresponds to a collection of signals transmitted from q groups of transmitting antennas, and where group k of transmitting antennas transmits n_k symbols that result from encoding a block of B_k bits with a coder employing code C_k.

6. The method of claim 4 where said decoding for receiving antenna group k is independent of decoding for receiving antenna group j≠

k.

7. The method of claim 4 where said decoding for receiving antenna group k is responsive to outputs decoded for receiving antenna groups j<

k.

8. The method of claim 7 where, in decoding for receiving antenna group k, the contribution to the signal received at the antennas of group k from signal decoded for receiving antenna groups j<

k is subtracted from the signal received at the antennas of group k.

9. A transmitter comprising:

means for partitioning an applied frame of B bits into q bit-groups where bit-group k has B_k bits and ##EQU12## q encoders, with encoder k, k=1,2, . . . ,q, being responsive to bit-group k, where the encoder k encodes the B_k bits into n_k symbols; and

means for transmitting each of the symbols developed by said q encoders out of n transmitting antennas, where ##EQU13##10.

10. The transmitter of claim 9 where said q encoders develop n symbols and the n-th symbol is transmitted by the n-th transmitting antenna.

11. The transmitter of claim 10 where the n symbols are transmitted out of the n transmitting antennas simultaneously.

12. The transmitter of claim 9 where said means for transmitting includes a modulator.

13. The transmitter of claim 9 where each of said q encoders employs an encoding code C_k that is a component code of a product code C₁ ×

C₂ ×

, . . . , ×

C_q.

14. The transmitter of claim 13 where each code said C_k is a trellis code.

15. A receiver comprising:

in antennas coupled to m receivers,

q processing units, each coupled to m_k of said receivers, where m_k is an integer such that ##EQU14## and means for combining output signals decoded by said q processing units.

16. The receiver of claim 15 where each of said processing unit includes a decoder employing a codeC_k that is a component code of a product code C₁ ×

C₂ ×

, . . . , ×

C_q.

17. The receiver of claim 15 where processing unit k subtracts a computed contribution to signals received at antennas coupled to said processing unit k of signals detected by processing units j<

k.

18. The receiver of claim 16 where said code C_k is a trellis code.

19. A method for transmitting signal over n antennas comprising the steps of:

in response to an applied frame of signals, developing q streams of codewords, where q is less than n, where the streams of codewords are independent of each other, and where the codewords within a stream are correlated to each other; and

transmitting the S streams of codewords over said n antennas.

20. The method of claim 19 where each stream of codewords k is transmitted by a group of said antennas having n_k antennas and ##EQU15##