基于最大后验概率准则的天基星座网络多用户检测方法

A maximum posteriori probability criterion based multiuser detection method in space based constellation networks

天基星座网络中用户可以随意进出自由组网,活动用户的数量、身份和发送的数据随机变化,对接收用户的性能造成很大影响。多用户检测是指识别每个活动用户的身份并检测每个活动用户发送的数据。传统方法假设活动用户数等于网络可以容纳的最大用户数,这种方法模型比较简单且误码率性能不够理想。提出了一种基于最大后验概率准则的多用户检测方法,该方法将用户的活动状态建模为马尔科夫链,并将多用户检测转换为在网格图中使用BCJR算法搜索最优路径。仿真结果表明,当活动状态错误概率和符号错误概率达到10^(-3)时,本文所提方法与对照方法相比分别获得2.6 dB和1 dB信噪比增益。

In space based constellation network,users are allowed to enter or leave the network arbitrarily.Hence,the number,identities and transmitted data of active users vary with time and have considerable impacts on the receiver’s performance.The so-called problem of multiuser detection means identifying the identity of each active user and detecting the data transmitted by each active user.Traditional methods assume that the number of active users is equal to the maximum number of users that the network can hold.The model of traditional methods is simple and the performance is suboptimal.A maximum posteriori probability(MAP)criterion based multiuser detection method was proposed.The proposed method models the state of users as Markov chain and transforms multiuser detection into searching optimal path in grid map with BCJR algorithm.Simulation results indicate that the proposed method obtains 2.6 dB and 1 dB E b/N 0 gains respectively when activity detection error rate and symbol error rate reach 10^(-3),comparing with reference methods.