Combined channel shortening and source separation with TIR controlled quality in MIMO-OFDM systems

Abstract

This paper considers the problem of channel shortening and source separation in MIMO-OFDM systems. The basic OFDM system uses a guard interval to eliminate the inter symbol interference (ISI) and the intercarrier interference (ICI). These interferences persist when the length of the channel is superior to the GI. We need then to shorten the channel. Using MIMO-OFDM allows to increase the bit rate but suffers from the co-channel interference. In this paper, we are interested in the case where the number of sensors is larger than the number of sources. It is known that in this case, several time domain equalizers (TEQ) can be obtained to shorten the channel. We exploit then these freedom degrees to suppress the co-channel interference and to control the Target Impulse Response (TIR) quality. Our processed system can be viewed as in form of N t parallel SISO-OFDM systems where N t is the number of sources. Simulation results are provided to illustrate this claim and to assess the performance of the proposed method.