Diversity technique for wireless communications

• US 8,355,475 B2
• Filed: 03/28/2011
• Issued: 01/15/2013
• Est. Priority Date: 09/16/1997
• Status: Expired due to Fees

• Current Assignee: AT&T Wireless Services Incorporated (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:
  US13/073,369
• Publication Number:
  US 20110170635A1
• Time in Patent Office: 659 Days
• Field of Search: 375/267, 375/316, 375/340, 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

A simple block coding arrangement is created with symbols transmitted over a plurality of transmit channels, in connection with coding that comprises only simple arithmetic operations, such as negation and conjugation. The diversity created by the transmitter utilizes space diversity and either time or frequency diversity. Space diversity is effected by redundantly transmitting over a plurality of antennas, time diversity is effected by redundantly transmitting at different times, and frequency diversity is effected by redundantly transmitting at different frequencies:

Claims

1. A method comprising:

receiving at a receiving device a wireless communication that includes a transmitted block of symbols transmitted from at least two space diverse antennas, the transmitted block of symbols being received at the receiving device over at least first and second transmit channels that couple the at least two space diverse antennas to the receiving device, the transmitted block including a first symbol and a complex conjugate of the first symbol and a second symbol and a negative complex conjugate of the second symbol, the first symbol and the complex conjugate of the first symbol being received over different ones of the first and second transmit channels, and the second symbol and the negative complex conjugate of the second symbol being received over different ones of the first and second transmit channels;

wherein the receiving of the transmitted block of symbols includes receiving the first symbol and the complex conjugate of the first symbol with one of frequency diversity or time diversity; and

wherein the receiving of the transmitted block of symbols further includes receiving the second symbol and the negative complex conjugate of the second symbol with frequency diversity if the first symbol and the complex conjugate of the first symbol are received with frequency diversity and receiving the second symbol and the negative complex conjugate of the second symbol with time diversity if the first symbol and the complex conjugate of the first symbol are received with time diversity.

2. The method as recited in claim 1 further comprising estimating channel characteristics of the at least first and second transmit channels.

3. The method as recited in claim 2 further comprising combining the received transmitted block of symbols in a combiner and supplying symbol estimates from the combiner using the estimated channel characteristics.

4. The method as recited in claim 3 further comprising supplying the symbols estimates to a maximum likelihood detector and recovering the first and second symbols.

5. The method as recited in claim 1 further comprising:

receiving the first symbol and the second symbol at an encoder;

encoding the received first and second symbols, the encoding including generating the complex conjugate of the first symbol and generating the negative complex conjugate of the second symbol;

transmitting the first symbol and the complex conjugate of the first signal from different ones of the space diverse antennas so as to be transmitted with space diversity; and

transmitting the second symbol and the negative complex conjugate of the second symbol from different ones of the space diverse antennas so as to be transmitted with space diversity.

6. The method as recited in claim 5:

wherein the transmitting of the first symbol and the complex conjugate of the first symbol utilizes frequency diversity; and

wherein the transmitting of the second symbol and the negative complex conjugate of the second signal utilizes frequency diversity.

7. The method as recited in claim 5:

wherein the transmitting of the first symbol and the complex conjugate of the first symbol utilizes time diversity; and

wherein the transmitting of the second symbol and the negative complex conjugate of the second signal utilizes time diversity.

8. A method of receiving a wireless communication that includes a transmitted block of symbols transmitted from at least two space diverse antennas to a receiving device, comprising:

receiving the transmitted block of symbols at the receiving device over at least first and second transmit channels that couple the at least two space diverse antennas to the receiving device, the transmitted block including a first symbol and a complex conjugate of the first symbol and a second symbol and a negative complex conjugate of the second symbol, the first symbol and the complex conjugate of the first symbol being received over different ones of the first and second transmit channels, and the second symbol and the negative complex conjugate of the second symbol being received over different ones of the first and second transmit channels;

wherein the first symbol and the complex conjugate of the first symbol are received with frequency diversity; and

wherein the second symbol and the negative complex conjugate of the second symbol are received with frequency diversity.

9. A method of receiving a wireless communication that includes a transmitted block of symbols transmitted from at least two space diverse antennas to a receiving device, comprising:

receiving the transmitted block of symbols at the receiving device over at least first and second transmit channels that couple the at least two space diverse antennas to the receiving device, the transmitted block including a first symbol and a complex conjugate of the first symbol and a second symbol and a negative complex conjugate of the second symbol, the first symbol and the complex conjugate of the first symbol being received over different ones of the first and second transmit channels, and the second symbol and the negative complex conjugate of the second symbol being received over different ones of the first and second transmit channels;

wherein the receiving of the transmitted block of symbols includes receiving the first symbol and the complex conjugate of the first symbol with time diversity; and

wherein the receiving of the transmitted block of symbols includes receiving the second symbol and the negative complex conjugate of the second symbol with time diversity.