Multiplying symbol streams by rectangular matrix of (P/M)×1 vectors
View Patent ↗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.
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
w
1
0
…
0
0
w
2
…
0
⋮
⋮
⋮
⋮
0
0
…
w
m
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.