链路相关无线网络中基于网络编码的机会转发机制

Network-coding-based Opportunistic Forwarding in Link-correlated Wireless Networks

多跳无线网络中数据包在不同链路的接收存在相关性,现有的基于网络编码的机会转发协议大多基于链路间相互独立的假设,严重降低其在实际网络中的性能表现.该文针对链路相关无线网络环境,提出基于网络编码的无线链路相关性感知的机会转发机制LCOF.首先结合链路相关性对基于网络编码的期望传输次数进行计算.在此基础上,提出数据包综合效用增益函数,以此确定数据包的转发优先级.随后提出多优先级数据包调度策略,确保高优先级数据包以更大的概率被转发.仿真结果表明,LCOF可以更好地利用编码机会,有效提高网络吞吐量.

Recent researches highlight the existence of link correlation of adjacent wireless links. Typical Network Coding based Opportunistic Forwarding protocols explicitly or implicitly assume that the packet reception in adjacent wireless links are independent, leading to performance degradation. A Network Coding based Opportunistic Forwarding mechanism, called LCOF, is proposed for link-correlated wireless networks. The existing ETX （Expected Transmission Count） are calculated based on the assumption of link independence,which omits the link correlation. LCOF takes link correlation into account when calculating the ETX. A network coding utility gain evaluation mechanism is presented to achieve multi-priority packet scheduling, building upon which a packet of higher utility is more likely to be selected earlier to be forwarded. The simulation results show that, the proposed LCOF can efficiently capture coding opportunities, thus improving network throughput.