OFDM subchannel space-combining transmission diversity for broadband wireless communication systems

This paper proposes a transmission diversity (TD) technique combined with orthogonal frequency division multiplex (OFDM) modulation to enhance packet-error-rate (PER) performance in microcell broadband wireless communication systems. The proposed TD technique selects the antenna with the anticipated better-channel conditions in a subchannel-by-subchannel manner at the access point (AP) based on the quality-measurement results of signals sent by the mobile terminal (MT). In the subsequent transmission timing from the AP to the MT, each antenna at the AP station transmits OFDM-modulated signals that only possess the selected subchannel components. On the MT side, the space-combined whole subchannel OFDM signal is received through the single antenna.