一种协作OFDM系统频偏与信道联合估计算法

摘要

协作OFDM系统中,OFDM技术的引入使协作通信系统对载波频偏非常敏感,很小的频偏就会引起子载波间干扰.因此,提出了协作OFDM系统中基于载波频偏与信道信息的盲估计算法.该算法将源节点与中继节点的数据发送分为两个阶段,频偏跟踪阶段两者交替半速发送,监测阶段两者全速发送.源节点与中继节点通过目的节点对频偏进行监测情况,实时调整各自的数据发送模式.仿真结果表明,提出的算法能很好地跟踪载波频偏变化并及时作出相应调整,不仅响应速度快,而且估计精度高.%In the cooperative OFDM system,the introduction of OFDM technology makes cooperative communication system very sensitive to carrier-frequency offset,and a small frequency offset would cause inter-subcarrier interference.Therefore,the blind estimation algorithm based on carrier frequency offset and channel information in cooperative OFDM systems is proposed.The algorithm divides the data transmission of source node and relay node into two stages:in frequency offset tracking phase,they are sent alternately at half speed;and in monitoring phase,they are sent at full speed.The source node and the relay node monitor the frequency offset via the destination node,adjust their respective data sending modes in real time.Simulation results indicate that the proposed algorithm can well track carrier frequency offset and make adjustment accordingly,and is fast in the response speed and high in the estimation precision.