An efficient adaptive bit loading for SFBC-OFDM over scattering channel

This paper studies an adaptive modulation technique combined with space-frequency block coded OFDM (SFBC-OFDM) over scattering channels. Chow´s adaptive bit loading algorithm is employed in the two transmitter antennas and two receiver antennas SFBC-OFDM. The channel state information (CSI) for adaptive modulation can be acquired more easily in SFBC-OFDM than in multiple input multiple output (MIMO) OFDM. Scattering channels are discussed on the condition of arbitrary spatially uncorrelated scattering (US) field with arbitrary propagation-loss factors. Then scattering function is presented. Simulation results show that adaptive SFBC-OFDM has 1.5 dB and 5 dB advantage compared with fixed modulation SFBC-OFDM and with adaptive OFDM respectively. Furthermore, adaptive SFBC-OFDM requires less additional power gain than fixed modulation SFBC-OFDM in mobile scattering channel.