Multiple transmit-and-receive antennas can be used in orthogonal frequency division multiplexing (OFDM) systems to improve communication quality and capacity. In this paper, we investigate the performance of a multiple antenna system with sub-channel power control for OFDM Wireless LAN. Furthermore, we employ turbo product codes at the encoder to further enhance the quality of transmission for high data rate WLAN such as the ETSI BRAN HIPERLAN/2. Simulation results shows that for a BER of 10^-4 we gain 4.4 dB for the proposed scheme with turbo block codes and subchannel power control compared to the standardized 5 GHz OFDM wireless LANS.