High data rate closed loop MIMO scheme combining transmit diversity and data multiplexing
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) providing estimates for communication channels from said P antennas to Q receive antenna(s) where Q is a positive integer;
(c) providing M symbol streams to transmit from said P antennas through said communication channels where M is an integer greater than or equal to 2, and said M symbol streams derive from a single input symbol stream;
(d) providing weights for said P antennas, said weights multiplying said symbols.
2. The method of claim 1 , wherein:
(a) said providing weights of step (d) of claim 1 includes maximizing a minimum signal-to-interference-plus-noise ratio of said M symbol streams after detection.
3. The method of claim 2 , wherein:
(a) said detection of claim 2 is selected from the group consisting of linear zero-forcing, linear minimum mean square error, iterative zero-forcing, and iterative minimum mean square error.
4. The method of claim 2 , wherein:
(a) said detection of claim 2 is maximum likelihood detector with SER selection criterion.
5. The method of claim 1 , wherein:
(a) said weights of step (d) of claim 1 correspond to a diagonal M×M block matrix of (P/M)×1 blocks where each (P/M)×1 block corresponds to weights for a symbol stream of said M symbol streams.
6. The method of claim 1 , wherein:
(a) said weights of step (d) of claim 1 correspond to a (P/M)×1 block matrix of M×M blocks where each M×M block is an M×M unitary matrix.
7. The method of claim 1 , wherein:
(a) said providing channel estimates of step (b) of claim 1 is by reception from said receiver in said channel.
8. The method of claim 1 , wherein:
(a) said providing channel estimates of step (b) of claim 1 is by reception of channel information from said receiver.
9. The method of claim 1 , wherein:
(a) said channel estimates of step (b) of claim 1 are updated; and
(b) said weights of step (d) of claim 1 are updated in response to said channel estimates update.
10. The method of claim 1 , wherein:
(a) said integer Q is greater than or equal to said integer P.
11. The method of claim 1 , wherein:
(a) said communication channels include multipath interference; and
(b) said detection accounts for said multipath interference;
Maximum likelihood +SER selection criterion.
12. The method of claim 11 , wherein:
(a) said detection of step (d) of claim 1 is selected from the group consisting of linear zero-forcing, linear minimum mean square error, iterative zero-forcing, and iterative minimum mean square error.
13. The method of claim 1 , wherein:
(a) said communication channel is a wideband or CDMA channel with multiple users.
14. The method of claim 1 , wherein:
(a) said communication channel is a wideband or CDMA channel with a single user with multiple codes.
15. The method of claim 1 , wherein:
(a) said communication channel is a narrowband or TDMA channel.
16. The method of claim 1 , wherein:
(a) said communication channel is an OFDM channel.
17. a transmitter, comprising: (a) P transmitt antennas where P is an interger which is a multiple of an integer M where M is greater than 1; (b) M data stream inputs coupled to said P antennas by P multiply M weights; said weights determined from both (i) information of communication channels from said P antennas to Q receive antenna(s) where Q is a positive integer, and (ii) a detection method for said M data streams inputs at said Q antenna(s), said M data stream inputs couple to a primary data stream input.
18. The transmitter of claim 17 , wherein: (a) said weights are all 0 except for M sets, each set of size K wherein P=M multiply by K, and each of said M sets couples one of said data streams to a set of K antennas.
19. The transmitter of claim 17 the transmitter wherein: (a) said weights are partitioned into K wherein P=M multiply by K sets, each set forming an M.times.M unitary transformation of symbols at said M data stream inputs, and each of said K sets couples said M data streams inputs to a corresponding set of M antennas.
20. The transmitter of claim 17 , wherein:
(a) said weights are determined outside of said transmitter and received by said transmitter from said signals from said Q antenna(s).