An efficient greedy loading algorithm for adaptive modulation in OFDM systems

This paper presents a new efficient bit and power loading algorithm for orthogonal frequency division multiplexing (OFDM) systems, which aims to minimize the transmit power while maintaining a constant data rate and target bit error rate (BER). This algorithm is based on greedy allocation approach. After grouping, sorting and clustering, the greedy allocation procedure is performed over clusters other than over all subchannels. Compared with conventional optimal loading algorithms, the proposed algorithm can reduce the algorithmic complexity significantly, and the performance degradation may be negligible if algorithmic parameters are selected appropriately. Simulation results indicate advantages of the proposed algorithm