EURASIP Journal on Wireless Communications and Networking 
Volume 2006 (2006), Article ID 64159, 9 pages
doi:10.1155/WCN/2006/64159

Relay Techniques for MIMO Wireless Networks with Multiple Source and Destination Pairs

Tetsushi Abe,1 Hui Shi,2 Takahiro Asai,2 and Hitoshi Yoshino2

 1DoCoMo Communications Laboratories Europe GmbH, 312 Landsbergerstreet, Munich 80687, Germany
2NTT DoCoMo, Inc., Japan
Received 1 November 2005; Revised 17 May 2006; Accepted 16 August 2006

Abstract

A multiple-input multiple-output (MIMO) relay network comprises source, relay, and destination nodes, each of which is equipped with multiple antennas. In a previous work, we proposed a MIMO relay scheme for a relay network with a single source and destination pair in which each of the multiple relay nodes performs QR decompositions of the backward and forward channel matrices in conjunction with phase control (QR-P-QR). In this paper, we extend this scheme to a MIMO relay network employing multiple source and destination pairs. Towards this goal, we use a group nulling approach to decompose a multiple S-D MIMO relay channel into parallel independent S-D MIMO relay channels, and then apply the QR-P-QR scheme to each of the decomposed MIMO relay links. We analytically show the logarithmic capacity scaling of the proposed relay scheme. Numerical examples confirm that the proposed relay scheme offers higher capacity than existing relay schemes.