Optimal binary training sequence design for multiple-antenna systems over dispersive fading channels

Accurate and efficient channel estimation is important in multiple-antenna communication systems in order to effectively reduce the mutual interference among different transmitting antennas. For a nondispersive channel that is modeled by a single tap for each transmitting and receiving antenna pair, the well-known Hadamard sequences can be applied to estimate the channel coefficients. However, for a dispersive channel that has multipath problem and is modeled by multiple taps, the optimal sequences must have both good autocorrelations and cross correlations. The existence of binary sequences with such good property is an open problem. In this paper, we devise an algorithm to find these sequence sets. These codes can be applied in multiple-antenna systems.