无线传感网物理层协作分集的性能分析

该文针对无线传感网中的远距传输问题,研究了一种无需网络同步和正交信道的协作分集方法的性能,给出了在两种典型信道中当解码转发存在误差传播时远程目的节点的误码率及分集指数;分析了当转发节点间为白高斯信道时增加协作节点数能够提高目的节点性能的条件.研究结果表明,当转发节点间为白高斯信道时,只要转发节点处于正常工作点,增加节点数就能提高目的节点的性能;当转发节点间为瑞利平衰落信道时,只有当转发节点处于一定位置时,协作分集相对于直接发送或传统空间分集才有性能增益;当转发节点间为瑞利平衰落信道时增加跳数性能更好,为白高斯信道时增加分支数更有效;当转发节点间为瑞利平衰落信道时,误差传播将使目的节点的分集指数为1,但在较低信噪比条件下对分集性能影响很小.

Performance Analysis of Cooperative Diversity at PHY Layer in Wireless Sensor Networks

In this paper,the performance of cooperative diversity for reach-back problem in wireless sensor networks is studied,in which network synchronization or orthogonal channels are not necessary. The bit error rate and diversity order of destination are respectively developed for two typical channels,considering the error propagation appeared in the decode-and-forward procedure. It's shown by the analysis that the increase of the node's number will improve the performance in destination if relays are at normal working point. To increase hop number is more effective for the scenario of AWGN channel among relays,while it is better to increase the number of branches when the channels among relays are Rayleigh fading. Cooperation diversity outperforms the direct transmission or the traditional spatio diversity if the relays are located in a certain region. Error propagation will reduce the diversity order of destination to 1,whereas almost has no influence on the diversity gain at the medium and low signal-noise-rate.