Communication over MIMO X Channel: Signalling and Performance Analysis

In a multiple antenna system with two transmitters and two receivers, a scenario of data communication, known as the X channel, is studied in which each receiver receives data from both transmitters. In this scenario, it is assumed that each transmitter is unaware of the other transmitter’s data (non-cooperative scenario). This system can be considered as a combination of two broadcast channels (from the transmitters point of view) and two multi-access channels (from receivers point of view). Taking advantage of both perspectives, two signaling schemes for such a scenario is developed. In these scheme, some linear filters are employed at the transmitters and the receivers which decompose the system into either two non-interfering multi-antenna broadcast sub-channels or two noninterfering multi-antenna multi-access sub-channels. By using the decomposition schemes, The material in this paper was presented in part at the IEEE International Symposium on Information Theory (ISIT), Seattle, WA, July 2006, and the technical report number UW-ECE 2006-12, University of Waterloo, Waterloo, July 2006. This work is financially supported by Communications and Information Technology Ontario (CITO), Nortel Networks, and National Sciences and Engineering Research Council of Canada (NSERC).