移动Ad hoc网络中基于自适应滤波的干扰抑制策略

Self Adaptive Filtering Based on Interference Suppression Game in Mobile Ad hoc Network

移动Ad hoc网络是一种由无线移动节点组成、不需要任何固定基础设施的无中心分布式无线网络。它依靠节点间的相互协作,在移动、复杂多变的无线环境中自行成网,借助于多跳转发技术来弥补无线设备的有限传输距离,从而拓宽网络的覆盖范围,为用户提供各种服务。移动Ad hoc网络中的所有实体之间的通信都采用无线多跳方式,这可能导致网络中相邻节点的连接没有保障。针对移动Ad hoc网络中带宽受限、误码率高、衰落、噪声、干扰等因素对通信性能的影响,本文提出一种基于先决干扰门限进行干扰抑制和频率子带选择的自适应滤波方法,并根据频带匹配原则和BER性能统计获得了高斯信道和多径衰落信道下的门限。对频率子带的动态选择,使得无须引入跳频技术便可获得较高的频谱利用效率,为改善带宽受限的移动Adhoc网络通信性能提出了新思路。采用交织扩频OFDM信号在不同干扰环境下对系统误码率进行模拟,基于NS2的仿真结果表明,本文所提出自适应滤波方法使系统BER性能最高可提高5dB。

Mobile Ad hoc Network （MANET） is a centerless packet radio network without any fixed infrastructure. It relies on a coordination between nodes to establish such kind of network in mobile and complex wireless environment with multi-hop forwarding way to remedy the defect of the limited transmission distance so as to broaden the network coverage and provide various services. In recent years, tremendous progress has been made with respect to capabilities of self-configuration and self-maintenance. However, the attenuation and the interference caused by node mobility and wireless channel sharing weaken the stability of communication links. The negative impact on communication performance in mobile Ad hoc network caused by limited bandwidth, high bit error rate, fade, noise, interference and so on, is alleviated by a sell adaptive filtering game based on frequency sub-bands and predetermined threshold obtained in Gauss and multipath fading channel according to frequency-matching principle and BER performance. This game uses sub-bands dynamically without frequency hopping techniques is introduced to greatly increase frequency spectrum utilization efficiency and to provide some new insight in improving communication performance. The effectiveness of the sell adaptive filtering method has been verified by ISS-OFDM in different interference conditions, and the simulating result based on NS2 indicates that the system bit error rates can be improved as far as by 5 dB.