论文部分内容阅读
MIMO(mltiple—input,mltiple-output)系统中不同发送天线发射的信号在接收天线上叠加,形成相互干扰,可以采用多用户检测算法进行解调以提高系统性能.因此提出将LDPC码解码理论中的置信度传播(belief propagation)思想引入MIMO系统的解调技术,从而得到了一种新的基于置信度传播的多用户检测算法.新算法的复杂度只与发送/接收天线数目的平方成正比.仿真结果表明,新算法在低信噪比条件下误比特率性能优于传统的线性MMSE多用户检测器,但在高信噪比条件下则存在误比特率的“地板效应”,因此比较适合于采用信道编码的系统.虽然该算法是基于MIMO系统地推导而来的,但显然它也可以被推广应用到一般的CDMA系统中去.
The signals transmitted by different transmit antennas in MIMO (mltiple-output) systems are superimposed on the receiving antennas to form mutual interference and can be demodulated by multi-user detection algorithm to improve the system performance. Therefore, it is proposed to decode LDPC codes in the theory of decoding (Belief propagation) is introduced into demodulation technology of MIMO system, a new multi-user detection algorithm based on belief propagation is obtained.The complexity of the new algorithm is only proportional to the square of the number of transmitting / receiving antennas The simulation results show that the new algorithm has better bit error rate performance than the traditional linear MMSE multiuser detector at low signal to noise ratio, but the “floor effect” with bit error rate under high signal to noise ratio Suitable for the system using channel coding.Although the algorithm is derived based on the MIMO system, but apparently it can also be extended to the general CDMA system to go.