Improving STBC Performance in IEEE 802.11n Using Group-Orthogonal Frequency Diversity

This paper proposes the use of group-orthogonal frequency diversity combined with space-time block coding (STBC) to improve the performance of IEEE 802.11n wireless networks (WLANs). The extra diversity is achieved by using code-division multiplexing whereby each symbol is transmitted on more than one subcarrier. At reception, following the STBC decoding, a maximum likelihood-based turbo receiver is used to take full advantage of the available diversity. The performance of the proposed scheme is investigated over the two different operating bandwidths specified in 802.11n, (20 or 40 MHz) and with different number of transmit antennas. Simulation results using the current IEEE 802.11n specifications serve to illustrate the benefits of the proposed scheme under realistic conditions.