High diversity time-space coding and decoding for MIMO systems

• US 8,107,543 B2
• Filed: 06/27/2006
• Issued: 01/31/2012
• Est. Priority Date: 06/27/2006
• Status: Active Grant

• Current Assignee: Amimon Limited (Vitec Group PLC)
• Original Assignee: Amimon Limited (Vitec Group PLC)
• Inventors: Feder, Meir, Doron, Eran, Bublil, Baruch
• Primary Examiner(s): LAM, KENNETH T
• Application Number:
  US11/426,898
• Publication Number:
  US 20070297528A1
• Time in Patent Office: 2,044 Days
• Field of Search: 375/260, 375/295, 375/259, 375/267, 375/300
• US Class Current: 375/260
• CPC Class Codes: H04L 1/0631 Receiver arrangements
• CPC Class Codes: H04L 1/0662 Limited orthogonality systems
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT

Abstract

A diversity transmission scheme uses a number of antennas that is greater than the limitation of two transmitting antennas in the well-known Alamouti scheme. In an embodiment comprising four antennas, the antennas transmit in pairs such that each antenna transmits a block that is used in the Alamouti scheme. This increases the transmission rate. For example, the transmission of two signals at a given time slot increases transmission rate by a factor of two. The invention not only increases the number of antennas, but also increases the transmission rate. At the receiver end, the code is decoded without matrix inversion and without much noise enhancement. Moreover, noise enhancement stability is increased by a simple, partial interference cancellation scheme, that results in improved decoding performance.

Claims

1. A method of wireless transmission, the method comprising:

receiving a plurality of antenna symbols via a plurality of pairs of transmission streams, wherein a pair of transmission streams represents a single pair of symbols at a given time, such that during a first time period each of said pairs of transmission streams includes a first pair of symbols and wherein during a second time period, each of said pairs of streams includes a second pair of symbols corresponding to complex conjugates of said first pair of symbols previously included in that stream;

generating an output corresponding to said at least two pairs of symbols by multiplying a received signal matrix which includes the at least two pairs of received symbols by a channel matrix of complex values representing fading characteristics between transmit and receive antennas and by a second matrix which second matrix is orthogonal to a product of the channel matrix with a conjugate transpose of the channel matrix; and

generating said output based on a product of said multiplying.

2. The method of claim 1, wherein a first diagonal of said second matrix comprises at least two diagonal sub-matrices, and a second diagonal of said second matrix comprises at least two sub-matrices orthogonal to one another.

3. The method of claim 2 comprising:

based a selection criterion related to the sub-matrices of said first diagonal, selecting a set from first and second sets, each including two or more symbols of the received symbols;

decoding symbols of the selected set; and

decoding symbols of another of said first and second sets based on the decoded symbols of said selected set.

4. The method of claim 2, wherein selecting the set comprises selecting the set based on a comparison between determinants of the sub-matrices of said first diagonal.

5. The method of claim 1, wherein during said first time period first and second streams of a pair of said plurality of pairs of transmission streams include first and second symbols, respectively, and wherein during said second time period said first and second streams include a negative conjugate of said second symbol and a conjugate of said first symbol, respectively.

6. The method of claim 5, wherein during said first time period third and fourth streams of another pair of said plurality of pairs of transmission streams include third and fourth symbols, respectively, and wherein during said second time period said third and fourth streams include a negative conjugate of said fourth symbol and a conjugate of said third symbol, respectively.

7. The method of claim 1, wherein said second time period is immediately subsequent to said first time period.

8. A wireless receiver to receive a plurality of antennas symbols via a plurality of pairs of transmission streams representing a plurality of different pairs of symbols, and to generate an output corresponding to said at least two pairs of symbols, wherein during a first time period each of said pairs of transmission streams includes a first pair of symbols, and wherein during a second time period each of said pairs of streams includes a second pair of symbols corresponding to complex conjugates of said first pair of symbols;

and

wherein said receiver is further adapted to multiply a received signal matrix which includes the at least two pairs of received symbols by a channel matrix of complex values representing fading characteristics between transmit and receive antennas and by a second matrix which second matrix is orthogonal to a product of the channel matrix with a conjugate transpose of the channel matrix; and

to generate said output based on a product of said multiplying.

9. The receiver of claim 8, wherein a first diagonal of said second matrix comprises at least two diagonal sub-matrices, and a second diagonal of said second matrix comprises at least two sub-matrices orthogonal to one another.

10. The receiver of claim 9 comprising a decoder to select, based a selection criterion related to the sub-matrices of said first diagonal, a set from first and second sets, each including two or more symbols of the received symbols;

to decode symbols of the selected set; and

to decode symbols of another of said first and second sets based on decoded symbols of said selected set.

11. The receiver of claim 10, wherein the decoder is to select the set based on a comparison between determinants of the sub-matrices of said first diagonal.

12. The receiver of claim 8, wherein during said first time period first and second streams of a pair of said plurality of pairs of transmission streams include first and second symbols, respectively, and wherein during said second time period said first and second streams include a negative conjugate of said second symbol and a conjugate of said first symbol, respectively.

13. The receiver of claim 12, wherein during said first time period third and fourth streams of another pair of said plurality of pairs of transmission streams include third and fourth symbols, respectively, and wherein during said second time period said third and fourth streams include a negative conjugate of said fourth symbol and a conjugate of said third symbol, respectively.

14. A multiple-input-multiple-output wireless transmission system comprising:

a wireless transmitter to transmit a plurality of pairs of wireless transmission streams via a plurality of transmit antennas, said plurality of pairs of transmission streams representing a plurality of different pairs of symbols, wherein during a first time period each of said pairs of transmission streams includes a first pair of symbols, and wherein during a second time period each of said pairs of streams includes a second pair of symbols corresponding to complex conjugates of said first pair of symbols;

a receiver to receive via a plurality of receive antennas symbols of the plurality of pairs of transmission streams, to generate an output corresponding to said at least two pairs of symbols; and

to multiply a received signal matrix which includes the at least two pairs of received symbols by a channel matrix of complex values representing fading characteristics between transmit and receive antennas and by a second matrix which second matrix is orthogonal to a product of the channel matrix with a conjugate transpose of the channel matrix; and

to generate said output based on a product of said multiplying.

15. The system of claim 14, wherein a first diagonal of said second matrix comprises at least two diagonal sub-matrices, and wherein a second diagonal of said second matrix comprises at least two sub-matrices orthogonal to one another.

16. The system of claim 15, wherein said receiver comprises a decoder to select, based a selection criterion related to the sub-matrices of said first diagonal, a set from first and second sets, each including two or more symbols of the received symbols;

to decode symbols of the selected set; and

to decode symbols of another of said first and second sets based on decoded symbols of said selected set.

17. The system of claim 16, wherein the decoder is to select the set based on a comparison between determinants of the sub-matrices of said first diagonal.

18. The system of claim 14, wherein during said first time period first and second streams of a pair of said plurality of pairs of transmission streams include first and second symbols, respectively, and wherein during said second time period said first and second streams include a negative conjugate of said second symbol and a conjugate of said first symbol, respectively.

19. The system of claim 18, wherein during said first time period third and fourth streams of another pair of said plurality of pairs of transmission streams include third and fourth symbols, respectively, and wherein during said second time period said third and fourth streams include a negative conjugate of said fourth symbol and a conjugate of said third symbol, respectively.