Optimal user scheduling and resource allocation strategy for AMC based OFDMA systems

We propose a cross-layer strategy that jointly optimizes user scheduling and resource allocation for adaptive modulation and coding (AMC) based orthogonal frequency multiple access (OFDMA). The objective of this paper is to maximize the system throughput as a function of the bit error rate (BER) and the spectral efficiency based on selected modulation and coding schemes (MCSs). The proposed optimal user scheduling and resource allocation (OSRA) strategy arranges the users in distinct queues according to their priorities and selects users in an optimal manner that guarantees fair services for users among different priority levels. Moreover, it allocates the available resources optimally over the utilized sub-channels. The transmitter of the investigated AMC-OFDMA system at the assigned base station (BS) divides the transmitted OFDMA frame into sub-channels depending on the number of the considered priority levels. Simulation results show that the performance of the investigated AMC-OFDMA system based on the proposed OSRA strategy outperforms the conventional approaches.