A novel constant-power bit loading algorithm for QAM modulated OFDM systems

A bit loading algorithm is presented for orthogonal frequency division multiplexing (OFDM) systems to minimize bit error rate (BER), where quadrature amplitude modulation (QAM) is employed. The target data bits are loaded onto selected subcarriers that have largest remaining signal-to-noise ratio (SNR_rem) values on a group-by-group basis. The number of iterations is determined by the maximum size of embedded constellations independently of the target bit rate. Analysis and simulation results show that the proposed algorithm has appealing merits in computational complexity and BER performance.