多媒体传感网中的频率同步研究

Research on Frequency Synchronization over Multimedia Wireless Sensor Networks

文中针对基于OFDM传输体制的多媒体传感网节点,提出了一种新的频偏估计算法。在频域,可以方便去除虚拟子载波上噪声的影响,提高性能,同时根据每个子载波的解调信噪比对各个子载波的估计结果,进行最大比加权平均,可以有效的克服频率选择性衰落的影响。采用信道的统计信息,本文提出了一种低复杂度,可实现的方法。算法的仿真结果表明本文提出的算法能有效的克服多径的影响,并且在性能上比时域估计和等增益平均的方法有较大的改进。

A new algorithm is proposed for carrier offset estimation in OFDM over the application of multimedia WSN. In frequency domain, the performance can be improved by deleting the noise on the virtual subcarriers. Mean while, by maximum ratio combing the estimate results according to the signal to noise ratio of the demodulated signal, the new algorithm minimized the influence of frequency selective fading. A practicable and low complexity weighting method is also presented by using the statistical information of channels. The simulation results indicate that the proposed algorithm can greatly overcome the effect of the multi-path fading, which is superior to the time domain algorithm and the equal gain combining algorithm.