Multi-Services' QoS Guarantee In Cognitive Radio Networks

Over the last few years, the spectrum resources become increasingly scarce with the rapid development of wireless network technology. One important reason for this phenomenon is that the traditional static spectrum allocation strategy had led to low utilization rate of spectrum resources. In this case, the concept of Cognitive Radio Networks(CRNs) has been proposed. The CRNs is composed by two kinds of users: the licensed primary users(PUs) and the unlicensed users(SUs) which enable to detect and access the licensed spectrum hole opportunistically. Compared with the traditional wireless network, the utilization rate of spectrum resources of CRNs will be significantly improved. In CRNs, improving the performance of SUs is the main aspect of present study, however, due to the dynamic nature of the spectrum resources, strict Qo S guarantee of cognitive radio networks is of great challenge, especially for multiple services.To solve the problem that how to provide Qo S guarantees for multi-services of unlicensed users, the contribution of this paper could be list as follows. Firstly, a continuous-time Markov chain model is established to analyze the performance of the cognitive radio network, moreover, we formulate a channel reservation scheme which reserves different channels for different services to strictly guarantee the Qo S of multi-services while maximizing the utility of the cognitive radio network. Secondly, we take a buffer for handoff secondary users into consideration and propose a handoff scheme for multi-services with various priorities. In addition, the computation complexity of solving the optimal channel reservation problem is simplified by a binary search due to the monotony of performance functions. The simulation results confirm the validity of the proposed optimal channel reservation for multi-services. Not only could it strictly guarantee the Qo S of multiple services respectively, but also maximize the performance of CRNs.