Time Synchronization And Control Channel Design In Cluster-based Cognitive Radio Networks

Cognitive radio is being viewed as the most promising technique to achieve Dynamic Spectrum Access and to mitigate the problem of increasing scarcity of spectrum resources. And it has received increasing attention. Meanwhile, in the field of Military Communication, cognitive radio will play an important role in aspect of efficient spectrum management, and anti-jamming communication, etc.MAC layer protocol, as an important part for cognitive radio, has been got an indepth study. But most of research focused on control channel rendezvous, spectrum sensing, and spectrum access, and the research on time synchronization in cognitive radio is very limited. What’s more, in cognitive radio networks, time synchronization is highly connected to control channel design. Based on these facts, this article will study the issue of the establishing of time synchronization, control channel design, and fine time synchronization in cluster-based cognitive radio networks.The main contributions of this article are as follows:(1)We designed a synchronization establishing protocol based on One-Way synchronization algorithm. We give a detailed description of the protocol, and then derive an analytical expression for the performance of One-Way synchronization algorithm in absence of Primary Users(PUs), and also we give an approximate expression for estimating the algorithm’s performance under different PUs’ activity intensity. In the Monte Carlo simulation, the correctness of above expressions is proved, and the performance of our proposed algorithm is also shown to be valid.(2)We proposed a dynamic split-phase control channel protocol. From the view of multiple channel networks, we firstly discuss the problem of control channel design, and then we choose the split-phase control channel protocol as our final candidate. However split-phase control channel protocol is suffered from the sensibility of ratio of the length of control information and the length of data information. And in order to handle it, we focus on the optimization of this ratio. Based on the result of optimization, we get the dynamic split-phase control protocol. Our dynamic split-phase control channel protocol outperforms the MMAC algorithm and MAP algorithm in the simulation.(3)We proposed a fine time synchronization protocol based on Four-Way synchronization algorithm. Thanks to the structure of split-phased control channel protocol, we get the Four-Way synchronization algorithm, which can jointly use both One-Way time packages in common control channel and Two-Way time packages in data communication channel. In the performance simulation, Four-Way algorithm shows better performance than both One-Way and Two-Way synchronization algorithms.