Performance of space-combining transmission diversity with OFDM for broadband wireless access systems

This paper proposes a new diversity technique for broadband wireless access systems that uses orthogonal frequency division multiplexing (OFDM) and describes its performance. This technique consists of two components. One is optimal antenna selection in the reception phase and the other is signal transmission over each OFDM subchannel. Simulations and experiments are used to verify that the proposed technique offers excellent performance. In addition, to offset the quantization noise caused by large differences in the received power levels on the different antennas, a new automatic gain controlling (AGC) method is proposed and its performance is described.