J. Balakrishnan, M. Rupp and H. Viswanathan
The design of optimal training sequences for channel estimation in multiple antenna systems is considered. The optimality criterion for training sequence design is derived and the design tradeoffs associated with the choice of training length is discussed. A few heuristic methods for the search of near-optimal training sequences are proposed. Optimal and near-optimal (binary) training sequences for multiple antenna systems are listed. The design of training sequences for a delay-diversity scheme is discussed. It is shown that the choice of identical training sequences, transmitted with the appropriate delays, is optimal for the delay-diversity scheme.