Multiplying symbol streams by rectangular matrix of (P/M)×1 vectors

• US 7,715,798 B2
• Filed: 08/30/2006
• Issued: 05/11/2010
• Est. Priority Date: 11/21/2001
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Onggosanusi, Eko N., Dabak, Anand G., Schmidl, Timothy M.
• Primary Examiner(s): Edouard; Patrick N.
• Assistant Examiner(s): PHUONG, DAI
• Application Number:
  US11/468,394
• Publication Number:
  US 20060291581A1
• Time in Patent Office: 1,350 Days
• Field of Search: 455444-453, 455/69, 455/562.1
• US Class Current: 455/63.1
• CPC Class Codes: H04B 7/0632 Channel quality parameters, e.g. channel quality indicator [CQI]
• 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]

Abstract

Closed loop multiple-antenna wireless communications system with antenna weights determined by maximizing a composite channel signal-to-interference-plus-noise ratio minimum. Multiplexed symbol streams over subsets of antennas enhance throughput.

Claims

1. A method of transmission of a symbol stream, comprising:

(a) providing P transmit antennas where P is an integer greater than or equal to 3;

(b) splitting a data stream into M symbol streams to transmit from the P antennas through communication channels where M is an integer greater than or equal to 2; and

(c) multiplying the symbol streams by a rectangular matrix that corresponds to a diagonal M×

M block matrix of (P/M)×

1 vectors where each (P/M)×

1 vector corresponds to weights for a symbol stream of the M symbol streams.

2. The method of claim 1 including deriving the weights from estimates of communication channels from said P antennas to at least one Q receive antenna where Q is a positive integer.

3. The method of claim 2 including detecting said M symbol streams at said Q antenna.

4. The method of claim 2 including detecting the M symbol streams using one of linear zero-forcing, linear minimum mean square error, iterative zero-forcing, and iterative minimum mean square error.

5. The method of claim 2 including detecting the M symbol streams using a maximum likelihood detector with SER selection criterion.

6. The method of claim 1 including selecting the weights from a finite set of P-by-M matrices.

7. The method of claim 1 including selecting the weights by maximizing a minimum signal-to-interference-plus-noise ratio of said M symbol streams after detection.

8. The method of claim 1 in which the weights correspond to a (P/M)×

1 vector matrix of M×

M blocks where each M×

M block is an M×

M unitary matrix.

9. The method of claim 1 including receiving the weights from a receiver in said channels.

10. The method of claim 9 including providing the weights from channel information in said receiver.

11. The method of claim 1 including:

(a) deriving said weights of step (c) from estimates of communication channels from said P antennas to at least one Q receive antenna;

(b) updating said channel estimates; and

(c) updating said weights in response to updating said channel estimates.

12. The method of claim 1 including deriving the M symbol streams from a single input symbol stream.

13. The method of claim 1, wherein at least one of said communication channels is a wideband or code division multiple access (CDMA) channel with multiple users.

14. The method of claim 1, wherein at least one of said communication channels is a wideband or CDMA channel with a single user with multiple codes.

15. The method of claim 1, wherein at least one of said communication channels is a narrowband or time division multiple access (TDMA) channel.

16. The method of claim 1, wherein at least one of said communication channels is an OFDM-type channel.

17. The method of claim 1 in which each antenna weight is a vector w_m corresponding to a symbol stream, and including providing weights in accordance with a weighting matrix V, where:

$V<br><br>\begin{array}{cccc}{w}_1& 0& \mathrm{\dots <br><br>}& 0\\ 0& w_2& \mathrm{\dots <br><br>}& 0\\ \mathrm{⋮<br><br>}& \mathrm{⋮<br><br>}& \mathrm{⋮<br><br>}& \mathrm{⋮<br><br>}\\ 0& 0& \mathrm{\dots <br><br>}& w_m\end{array}$

where each vector w_m belongs to a set of (P/M)×

1 vectors.

18. The method of claim 1 including transmitting from each P transmit antenna in user equipment.

19. The method of claim 1 including transmitting from each P transmit antenna in a mobile device.

20. The method of claim 1 including transmitting from each P transmit antenna a symbol stream multiplied by a weight.