Adaptive subcarrier, bit, and power allocation algorithm for MIMO-OFDMA system

Abstract

We investigate an adaptive subcarrier, bit, and power allocation algorithm for the downlink MIMO-OFDMA system. Using the singular value decomposition, the MIMO fading channel of each subcarrier is transformed into an equivalent bank of parallel SISO sub-channels. For the efficient allocation of the banks of parallel sub-channels, we define the problem of minimizing total transmit power with constraints on BER and transmission rate for users. Using the simplified problem formulation, we propose a sub-optimal adaptive subcarrier, bit, and power allocation algorithm which outperforms the fixed subcarrier allocation in the MIMO-OFDMA system.