基于BLLR-GSC的MQAM-OFDM系统性能

Performance of OFDM-MQAM Systems with Generalized Selection Combining Based on the Bit Log-likelihood Ratio

研究频率选择性相关Nakagami-m衰落信道上基于信噪比广义选择合并(SNR-GSC)和基于比特对数似然比广义选择合并(BLLR-GSC)分集接收,采用M进制正交幅度调制方式的正交频分多路复用(MQAM-OFDM)系统的误比特率性能。仿真结果表明采用L支路最大比合并分集接收的MQAM-OFDM系统的误比特率,L支路中选择L/2支路的基于BLLR-GSC分集接收的MQAM-OFDM系统的误比特率相等;在接收天线数和选择天线数相同的情况下,BLLR-GSC分集接收的MQAM-OFDM系统的误比特率性能要优于基于SNR-GSC分集接收的MQAM-OFDM系统。

The performance of the bit-error rate for M-ary quadrature amplitude modulation(MQAM) signals in orthogonal frequency-division multiplexing(OFDM) systems with generalized selection combining scheme based on signal-to-noise ratio(SNR-GSC)and bit log-likelihood ratio(BLLR-GSC) on correlated frequency-selective Nakagami-m fading channels have been investigated respectively.Simulation results show that the bit-error rate for MQAM-OFDM systems with maximal-ratio combining(MRC) diversity reception scheme of L branches is identical to that with BLLR-based GSC of L/2 branches.The performance of BLLR-based GSC is better than the SNR-GSC with the same number of receive antennas and selection antennas.