Comparison of space division multiplexing schemes employing multiple antennas in OFDM forward link

The paper compares the achievable throughput performance of the multiple antenna transmission and reception technique called MIMO (multiple-input multiple-output) including the adaptive antenna array beamforming (AAA-BF) transmitter, using a 100 MHz bandwidth for the OFDM (orthogonal frequency division multiplexing) forward link in a multipath Rayleigh fading channel aiming at high frequency efficiency up to 10 bps/Hz. Simulation results elucidate that to achieve high frequency efficiency of greater than approximately 4 bps/Hz, MIMO multiplexing can decrease the required transmission power the most for two and four transmitter and receiver antennas, since lower-level data modulation or a lower channel coding rate is applicable compared to the AAA-BF transmitter and MIMO diversity schemes. We also show that an average PER of 10^-2 is possible for the information bit rate of 1 Gbps using a 100 MHz bandwidth (i.e., 10 bps/Hz) at the transmit signal energy per bit-to-background noise power spectrum density ratio (E_b/N₀) of approximately 10 (13) dB using the combination of 16QAM modulation and the coding rate of 5/6 together with four-branch MIMO multiplexing in a 12-path fading channel with the maximum Doppler frequency of f_D=20 Hz when the fading correlation between antennas is 0 (0.6).