Receiver diversity technique for wireless communications

• US 7,386,077 B2
• Filed: 09/28/2006
• Issued: 06/10/2008
• Est. Priority Date: 09/16/1997
• Status: Expired due to Fees

• Current Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Original Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Inventors: Alamouti, Siavash, Tarokh, Vahid
• Primary Examiner(s): Corrielus, Jean B.
• Application Number:
  US11/536,474
• Publication Number:
  US 20070110179A1
• Time in Patent Office: 621 Days
• Field of Search: 375/259, 375/267, 375/347, 375/349
• US Class Current: 375/347
• CPC Class Codes: H04B 1/02 Transmitters
• CPC Class Codes: H04B 7/0613 using simultaneous transmission H04B7/0686 takes precedence
• CPC Class Codes: H04B 7/0615 of weighted versions of same signal
• CPC Class Codes: H04B 7/0667 of delayed versions of same signal using space-time coding H04L1/0618
• CPC Class Codes: H04B 7/0669 using different channel coding between antennas space-time coding H04L1/0618
• CPC Class Codes: H04B 7/0671 using different delays between antennas
• CPC Class Codes: H04B 7/0689 using different transmission schemes, at least one of them being a diversity transmission scheme
• CPC Class Codes: H04B 7/0837 using pre-detection combining H04B7/0868 takes precedence
• CPC Class Codes: H04B 7/0845 per branch equalization, e.g. by an FIR-filter or RAKE receiver per antenna branch rake receivers as such H04B1/7115
• CPC Class Codes: H04B 7/0854 using error minimizing algorithms, e.g. minimum mean squared error [MMSE], "cross-correlation" or matrix inversion
• CPC Class Codes: H04B 7/0857 using maximum ratio combining techniques, e.g. signal-to- interference ratio [SIR], received signal strenght indication [RSS]
• CPC Class Codes: H04B 7/0891 Space-time diversity rake receivers H04B1/7115; space-time decoding H04L1/0631
• CPC Class Codes: H04B 7/12 Frequency diversity
• CPC Class Codes: H04L 1/0054 Maximum-likelihood or sequential decoding, e.g. Viterbi, Fano, ZJ algorithms
• CPC Class Codes: H04L 1/04 using frequency diversity
• CPC Class Codes: H04L 1/0606 Space-frequency coding
• CPC Class Codes: H04L 1/0618 Space-time coding
• CPC Class Codes: H04L 1/0625 Transmitter arrangements
• CPC Class Codes: H04L 1/0631 Receiver arrangements
• CPC Class Codes: H04L 1/0643 block codes
• CPC Class Codes: H04L 1/0668 : Orthogonal systems, e.g. using Alamouti codes
• CPC Class Codes: H04L 1/08 : by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04L 25/0202 : Channel estimation

Abstract

An electronic circuit for decoding wireless communication signals comprises: a combiner adapted to receive one of an incoming time diverse or frequency diverse signal representing blocks of encoded symbols. The blocks of symbols have been transmitted by a plurality of spatially diverse antennas. The combiner is configured to combine the received encoded symbols The received encoded symbols include negated selected symbols and conjugated selected symbols. A maximum likelihood detector is configured to receive the one of a time diverse or a frequency diverse signal. The detector receives the combined encoded signals and recovers transmitted signals using a channel transfer function.

Claims

1. A method of receiving a wireless communication from first and second space diverse antennas, the wireless communication being further one of time diverse or frequency diverse, the method comprising the steps of

estimating characteristics of a transmit channel over which signals are received from said space diverse antennas and outputting said estimated characteristics to a signal combiner and a maximum likelihood detector, the characteristics being related to a time difference between sequential transmissions from said space diverse antennas;

combining said signals received from said first and second space diverse antennas and outputting said combined signals to said maximum likelihood detector as two output data signals responsive to said estimated channel characteristics;

and detecting respective transmitted signals in the presence of noise via said maximum likelihood detector responsive to said estimated channel characteristics.

2. A method of receiving a wireless communication as recited in claim 1, further comprising initially receiving a known transmitted signal.

3. A method of receiving a wireless communication as recited in claim 1, further comprising feeding back the detected transmitted signals.

4. A method of receiving a wireless communication from first and second space diverse antennas, the wireless communication comprising first, second, third and fourth transmitted signals, the method comprising

combining first and second transmitted signals and noise to develop a first received signal and combining conjugates of said first and said second transmitted signals and said noise to develop a second received signal,

developing channel estimates of the first and second transmitted signals from said first and second received signals and applying said channel estimates to a maximum likelihood detector;

recovering, using said maximum likelihood detector, said first and second transmitted signals responsive to said developed channel estimates; and

developing further channel estimates to recover said third and fourth transmitted signals.

5. A method of receiving a wireless communication as recited in claim 4 further comprising initially receiving a known transmitted signal.

6. A method of receiving a wireless communication as recited in claim 4 further comprising feeding back the recovered first, second, third and fourth transmitted signals.

7. An electronic circuit for decoding wireless communication signals, comprising:

a combiner adapted to receive one of an incoming time diverse or frequency diverse signal representing blocks of encoded symbols, wherein the blocks of symbols have been transmitted by a plurality of spatially diverse antennas, wherein the combiner is configured to combine the received encoded symbols, and wherein the received encoded symbols include negating selected symbols and conjugating selected symbols, and

a maximum likelihood detector configured to receive said one of a time diverse or a frequency diverse signal, the detector receiving the combined encoded signals and recovering transmitted signals using a channel transfer function.

8. An electronic circuit as recited in claim 7, the combiner initially receiving a known transmitted signal.

9. An electronic circuit as recited in claim 7, the maximum likelihood detector feeding back the recovered transmitted signals.

10. A method of receiving a wireless communication from first and second space diverse antennas, the wireless communication being further one of time diverse or frequency diverse, the method comprising the steps of

estimating characteristics of a transmit channel over which signals are received from said space diverse antennas and outputting said estimated characteristics to a signal combiner and a detector using a decision rule, the characteristics being related to a time difference between sequential transmissions from said space diverse antennas;

combining said signals received from said first and second space diverse antennas and outputting said combined signals to said detector as two output data signals responsive to said estimated channel characteristics;

and detecting respective transmitted signals in the presence of noise via said detector using said decision rule responsive to said estimated channel characteristics.

11. A method of receiving a wireless communication as recited in claim 10 further comprising receiving a known transmitted signal.

12. A method of receiving a wireless communication as recited in claim 10 further comprising feeding back the detected transmitted signals.

13. A method of receiving a wireless communication from first and second space diverse antennas, the wireless communication being further one of time diverse or frequency diverse, the method comprising the steps of

estimating characteristics of a transmit channel over which signals are received from said space diverse antennas and outputting said estimated characteristics to a signal combiner and a detector, the characteristics being related to a time difference between sequential transmissions from said space diverse antennas;

combining said signals received from said first and second space diverse antennas and outputting said combined signals to said detector as two output data signals responsive to said estimated channel characteristics;

and detecting respective transmitted signals in the presence of noise via said detector responsive to said estimated channel characteristics.

14. A method of receiving a wireless communication as recited in claim 13, further comprising initially receiving a known transmitted signal.

15. A method of receiving a wireless communication as recited in claim 13, further comprising feeding back the detected transmitted signals.

16. A method of receiving a wireless communication from first and second space diverse antennas, the wireless communication comprising first, second, third and fourth transmitted signals, the method comprising

combining first and second transmitted signals and noise to develop a first received signal and combining conjugates of said first and said second transmitted signals and said noise to develop a second received signal,

developing channel estimates of the first and second transmitted signals from said first and second received signals and applying said channel estimates to a decoder using a decision rule;

recovering, using said decoder, said first and second transmitted signals responsive to said developed channel estimates; and

developing further channel estimates to recover said third and fourth transmitted signals using said decoder.

17. A method of receiving a wireless communication as recited in claim 16 further comprising initially receiving a known transmitted signal.

18. A method of receiving a wireless communication as recited in claim 16 further comprising feeding back the recovered first, second, third and fourth transmitted signals.

19. An electronic circuit for decoding wireless communication signals, comprising:

a combiner adapted to receive one of an incoming time diverse or frequency diverse signal representing blocks of encoded symbols, wherein the blocks of symbols have been transmitted by a plurality of spatially diverse antennas, wherein the combiner is configured to combine the received encoded symbols, and wherein the received encoded symbols include negating selected symbols and conjugating selected symbols, and

a detector configured to receive said one of a time diverse or a frequency diverse signal, the detector receiving the combined encoded signals and recovering transmitted signals using a channel transfer function.

20. An electronic circuit as recited in claim 19, the combiner initially receiving a known transmitted signal.

21. An electronic circuit as recited in claim 19, the detector feeding back the recovered transmitted signals.

22. An electronic circuit as recited in claim 19, wherein said transmitted symbol blocks are distorted by a complex multiplication distortion factor composed of a magnitude and a phase response, said channel transfer function being related to said complex multiplication distortion factor.