CFBM-MC-CDMA通信系统下行链路的性能分析

Downlink performance analysis of a CFBM-MC-CDMA communication system

提出了一种基于复数滤波器组调制的多载波码分多址 (CFBM MC CDMA)通信系统模型 ,并在理论上分析了系统下行链路采用等增益合并和最大比合并 2种检测方法时在瑞利多径衰落信道下的性能 ,系统采用等增益合并时的性能优于采用最大比合并时的性能 .系统由于采用优化复数滤波器组调制 ,子载波频谱边沿衰落比较陡 ,相邻子载波频谱重叠比较少 ,等效于加入频率保护间隔 ,不需要传统系统采用的时间保护间隔 .仿真结果表明所提出的系统具有较低的信道间干扰和较强的抗多径干扰和窄带干扰的鲁棒性 ,其低信噪比时的性能明显好于传统的基于DFT变换的MC CDMA系统的性能 .

A complex filter bank modulation based multicarrier code division multiple access (CFBM-MC-CDMA) communication system model is presented, and its performance for downlink over Rayleigh multipath fading channel is analyzed. Two detection strategies of equal gain combining (EGC) and maximum ratio combining (MRC) are compared. The system with EGC performs better than that with MRC. Because the spectrum overlapping between adjacent subchannels is greatly decreased since the spacing between center frequencies of two neighboring subchannels is greater than the reciprocal of symbol period, its performance is improved. The simulation results show that the proposed system suffers lower interchannel interference to make its response more robust against multipath fading and narrowband interference. When the signal to noise ratio (SNR) is low, its performance is better than that of the conventional discrete Fourier transformation (DFT) based MC-CDMA system.