空时分组码在时变衰落信道中的性能

从实用性出发,对空时分组码在时变衰落信道中的性能进行了研究.采用SIMULINK仿真工具构造了时变衰落信道的仿真模型,模型由信道、发射端和接收端组成:信道部分由多径Rayleigh信道和高斯白噪声构成;发射端由信源、串并转换器、调制器、空时分组编码器和功率分配模块构成;接收端由信号合并、最大似然译码器、调制解调器和误比特率计算模块组成.仿真结果表明:在平坦慢衰落信道中,STTD性能比单收发系统的性能有很大提高,并且随着SNR的增大,STTD性能的提高幅度增大;在平坦时变衰落信道中,随着最大多普勒频移的增大,STTD性能有所下降,尤其是在大信噪比条件下,性能下降得更明显.

Performance of Space-Time Block Code in Time-Varying Fading Channel

The performance of STBC(space-time block code) in time-varying fading channel is studied with its practicability in focus.A simulation model in time-varying fading channel is developed using SIMULINK,which consists a channel,transmitting end and receiving end.Further,the channel comprises a multipath Rayleigh channel and Gaussian white noise,the transmitting end comprises signal source, serial-parallel converter,modulator,STBC and power dividing block and the receiving end comprises signal combiner,maximum likelihood decoder,modem and BER computing block.Simulating results indicated that in a flat and slowly fading channel the performance of STTD(space-time transmit diversity) is much better than it in single transmitting/receiving case and can be improved quickly with increasing SNR.But,if in a flat time-varying fading channel,the performance of STTD degrades with increasing maximum Doppler shift especially in case of high SNR.