一种异步的认知无线电网络跳频算法

Asynchronous Channel Hopping Algorithm for Cognitive Radio Networks

针对认知无线电网络中次用户对之间的交会问题,即次用户对在同一时间接入到相同的信道,提出了一种异步的基于循环请求集的跳频算法(ACHA).首先,次用户将可用的空闲信道按照循环请求集的结构生成跳频序列,然后再跟随跳频序列依次接入到可用信道中.利用循环请求集系统的旋转相交特性,ACHA算法能够保证任意2个次用户之间的交会必然发生在一个基本跳频序列周期之内.仿真结果表明:与正交序列跳频算法和基于三角形数的跳频算法相比,ACHA算法能将平均交会时间降低20%和40%

An asynchronous channel hopping algorithm（ACHA） based on the cyclic quorum is proposed to realize rendezvous in cognitive radio networks（CRNs）.Rendezvous means that secondary users（SUs） access the same channel at the same time.SU uses the structure of the cyclic quorum and generates the channel hopping sequences from its available idle channels.Then SUs tune themselves to their available channels following the channel hopping sequences.The ACHA makes use of the rotation closure property of the cyclic quorum system,and ensures the rendezvous between any two SUs to be realized within a basic channel hopping sequence period.Simulation results and comparisons with the generated orthogonal sequence-based algorithm and the triangular numbers-based algorithm show that the proposed algorithm can reduce the average time of rendezvous by 20% and 40%,respectively.