CDMA中的QAM调制迭代PDA联合检测方法

为提高检测器性能并在检测器和信道解码器之间充分利用已知信号信息,多天线系统的广义概率数据关联检测算法被推广到多用户联合检测中.基于Turbo迭代原理,通过基于此算法的迭代多用户检测器和多电平正交调制以及软入软出的前向纠错编码的结合,提出一种软入软出的广义概率关联算法与软入软出的信道解码方法有机结合的新型迭代多用户检测方法.该方法利用外部信息在检测器与解码器之间的交换,进行干扰抵消并进行联合解码和判决.计算机仿真显示该方案收敛所需的迭代次数比传统的使用线性最小均方误差的联合检测解码方案少5次左右,且其误比特率性能接近最大似然接收机的性能.

Iterated PDA Detector for CDMA Systems with QAM Constellation

Here a GPDA(Generalized PDA) method from MIMO(Multiple Input Multiple Output) systems is generalized to multi-user detection scenario,which detects square QAM(Quadrature Amplitude Modulation) modulated rather than BPSK(Binary Phase Shift Key) modulated symbols,and a SISO(Soft Input Soft Output) multi-user detector(MUD) scheme is presented.By concatenating SISO channel decoder with this novel SISO MUD,and by iteratively exchanging external information between,a new SISO GPDA+SISO FEC(Forward Error Correction) joint MUD detector is deducted.Simulation results justify the fast-convergence probability(about 5 iterations less than LMMSE(Linear Minimum Mean Square Error) scheme)and near-ML(Maximum Likelihood) performance of this method.