摘要
针对在双选信道下OFDM系统需要同时获取精确的载波偏移和信道状态信息,而采用贝叶斯MAP算法进行联合载波频率偏移和信道状态估计复杂度过高的问题,提出一种基于EM-MAP的联合CFO双选信道估计算法。首先利用基扩展模型解决信道状态由于快时变带来的可辨识问题,然后引入期望最大化(EM)算法对系统的载波频偏和信道状态信息进行联合估计,避免大规模的矩阵求逆,降低算法复杂度。仿真结果表明,该方法能获取与MAP算法相当的估计性能,且大幅度降低了复杂度,有效地解决了双选信道下进行联合估计复杂度过高的问题,具有很好的实用性。
This paper proposed an joint carrier frequency offset and double selective channel estimation method based on EM-MAP algorithm for the problem that the OFDM systems need to obtain precise carrier offset and channel state information under double selective channel, while the existing joint CFO and channel estimation method based on Bayesian MAP algorithm was much too complex. First it used an exponential basis expansion model to solve the channel identification problem due to the fast time-varying channel. Then introduced an expectation-maximization （EM） algorithm for joint estimation of the carrier frequency offset and channel state information, which avoided large-scale matrix inversion and reduced the algorithm complexity. The simulation results prove that this method can get a similar estimation performance compared with the MAP algorithm as well as a significant reduction in complexity, which effectively solves the problem of high complexity caused by joint estimation under double selective channel and demonstrates good usability.
出处
《计算机应用研究》
CSCD
北大核心
2014年第1期269-272,共4页
Application Research of Computers
基金
国防预研基金资助项目(41101040402)
关键词
期望最大化
双选信道
联合估计
正交频分复用
基扩展模型
expectation-maximization double selective channel joint estimation OFDM BEM channel model
