基于GA-MP的低复杂度OTFS检测算法

针对正交时频空(Orthogonal Time Frequency Space, OTFS)通信系统信号检测复杂度高的问题，提出一种改进的高斯近似消息传递(Gaussian Approximate Message Passing, GA-MP)检测算法。依据最大后验概率检测准则，对发送信号及隐变量进行逐符号高斯近似，基于置信传播算法与联合因子图进行消息传递，用边缘后验概率替代GA-MP中的外部信息以减少运算量，结合阻尼因子提升收敛速度，同时引入概率阈值减少后续更新的节点数，从而使运算复杂度得到有效降低。实验结果表明，改进后的GA-MP算法在保证误码率性能的前提下具有更低的复杂度。

A Low Complexity OTFS Detection Algorithm Based on GA-MP

For the high complexity of signal detection in an orthogonal time frequency space(OTFS) communication system,an improved Gaussian Approximate Message Passing(GA-MP) detection algorithm is proposed.According to the maximum a posteriori probability detection criterion,sign by sign Gaussian approximate for the transmitted signal and hidden variables is proformed,and the message is transmitted based on the belief propagation algorithm and the joint factor graph.The marginal a posteriori probability is used to replace the extrinsic information in GA-MP to reduce the amount of computation,and the convergence speed is improved in combination with the damping factor.At the same time,the probability threshold is introduced to reduce the number of subsequent updated nodes,so that the computational complexity is effectively reduced.The experimental results show that the improved GA-MP algorithm has lower complexity under the premise of ensuring the bit error rate performance.