无线认知自组网报文多播问题: 随机网络编码方法

基于随机网络编码技术研究了无线认知自组网的报文多播传输技术.首先提出报文多播传输的核心问题,称作多信道单跳报文多播问题(multi-channel single-hop wireless multicast problem,MCSHWMP),并且给出多信道单跳报文多播问题的定义,基于此提出其四元模型;然后提出基于网络编码技术的无线认知自组网报文多播传输算法框架,并根据该框架提出几种候选算法.所提算法通过网络编码技术充分利用无线通信的广播性质,显著节省了无线认知自组网报文多播传输报文传输数量;综合考虑无线认知自组网传输网络节点间不同信道的访问权限及报文的传输质量,使上游网络节点的每次报文传输都能使后续节点的报文收益得到最大化;从而有效节省多播传输组合报文中用于解码的附加信息,同时降低无线认知自组网传输报文的长度.仿真测试与分析结果表明,针对多信道单跳报文多播问题基于网络编码技术的算法相对于非网络编码算法明显节省报文传输数量,且在链路报文传输成功率较高但小于1时优势较大,节省报文数量可达50%.

Approach to multicast problems of cognitive-radio-network a random network coding based approach

Packet multicast technology in cognitive radio ad-hoc networks (CRAN) is researched using a random network coding (RNC) based approach. A basic problem, which is termed as multi-channel single-hop wireless multicast problem (MCSHWMP), of packet multicast applications in CRAN is investigated. Definition about MCSHWMP and its 4-element tuple model were provided. A network coding based scheme framework for packet multicast applications in CRAN is described and based on which, several candidate schemes are proposed. Exploiting the broadcast nature of wireless transmissions by using RNC, necessary packet transmissions are reduced greatly. Considering opportunistic accessibility of wireless channels and heterogeneous packet reception success ratio of different wireless channels, each packet transmission is tried to maximize the packet reception gain of the receivers. Packet size to be transmitted is effectively shortened by reducing decoding information to be transmitted in the packet. Simulation results showed that, network coding based schemes can save much packet transmissions when compared with non-network coding based schemes, and the superiority of network coding based schemes is more distinctive when packet reception success ratio of wireless links is nearly but smaller than 1, in those cases, nearly 50% packet transmissions could be saved.