STBC MC-CDMA系统自适应MBER多用户检测算法

Adaptive MBER Multi-User Detection Algorithm for STBC MC-CDMA Systems

针对MC-CDMA(Multicarrier code division multiple access)系统,描述了其时变多径衰落环境下采用空时分组编码(Space-time block coding,STBC)的同步上行链路模型,提出一种基于最小误比特率(Minimum biter-ror rate,MBER)的多用户检测算法。利用内核密度估计和梯度下降的方法,推导了该算法自适应实现形式。对具有2个发射天线和2个接收天线的STBC MC-CDMA同步上行链路系统进行了自适应MBER检测算法的计算机仿真。结果表明:当系统负荷较小时,该算法误码性能较好;当系统负荷较大时,该算法误码性能有所下降,但仍然优于具有类似计算复杂度的MMSE(Minimum mean squared error)自适应检测算法。

MC-CDMA system has been extensively studied in recent years.Its uplink synchronization model is described using space-time block coding in time-varying multi-path fading environment,and a new multi-user detection algorithm based on minimun bit error rate（MBER） is proposed.By using kernel density estimation and the gradient descent method,an adaptive realization form of the algorithm is deduced.The adaptive MBER detection algorithm for STBC MC-CDMA system with two transmit antennas and two receive antennas is simulated by computer.Simulation results show that the BER performance of this algorithm is very good when the system load is low,and the BER performance declines when the system load is heavy while it is still better than that of the adaptive detection algorithm based on minimum means squared error（MMSE） with similar computing complexity.