Spatial Multiplexing in OFDM Systems with Cyclic Delay Diversity

Cyclic delay diversity can be used to increase the frequency selectivity of the wireless channel seen from the receiver. In this work, we have used this simple technique on top of a spatial multiplexing based orthogonal frequency division multiplexing system. In our analysis, it is found that nearly 2 b/s/Hz of 10% outage capacity improvement can be achieved on a basic 2times2 system. This is achieved with little changes at any standard spatial multiplexing system. Also, the number of transmit antennas can be increased to increase the link capacity without making any changes to the receiver. Thus, the proposed technique can be used with any existing MIMO-OFDM system. We have shown significant improvement in FER by using this scheme compared to a simple spatial multiplexing scheme.