Spectrum Efficiency for Rate-Adaptive MIMO OSFBC-OFDM Systems Over Various Adaptation Policies
In this paper, closed-form expressions for capacities per unit bandwidth for multiuser MIMO-OFDM systems employing Orthogonal Space-Frequency Block Coding (OSFBC) over multipath frequency-selective fading channels are derived for optimal power adaptation, optimal rate adaptation with constant transmit power, channel inversion with fixed rate, and truncated channel inversion adaptation polices. A Signal to Noise Ratio (SNR) based user selection scheme is considered. Closed form expressions are derived for OSFBC-OFDM system. Optimal power adaptation policy provides the highest capacity over the other adaptation policies. Capacity gains are more prominent for optimal rate adaptation with constant transmit power policy as compared to other adaptation policies.