Research Of Dynamic Spectrum Access Strategies

With increasing demand for wireless communication, we find that spectrum has become one of the most important and scarce resources. In order to solve the problem of spectrum scarcity, a promising wireless network paradigm, Cognitive Radio (CR), is proposed. Cognitive radio technology has a lot of peculiar technical advantages, the main advantages are that it could improve the spectrum utilization and improve the wireless communication's performance.Dynamic Spectrum Access (DSA) is the core technology of the cognitive radio. Through spectrum perception technology, the system detects the "spectrum hole", then allocates the "spectrum hole" to the cognitive users. By contract with static spectrum access technology, dynamic spectrum access could increase the spectrum utilization.This paper mainly investigates the strategies of the dynamic spectrum access technology, and compares performances of the various strategies. Firstly, dynamic spectrum access without buffer queue and its performances are introduced, then, we focus on the dynamic spectrum access with buffer queue. According to the properties of the buffer queue, dynamic spectrum access with buffer queue falls into two categories:buffer queue without priority (that is, the rule of the buffer queue is first come first leave) for dynamic spectrum access and buffer queue with priority for dynamic spectrum access. After analysis of the various dynamic spectrum access methods, comparision has been made between these strategies, and simulation results are given in the paper.In one word, dynamic spectrum access technology can improve the spectrum utilization greatly. By introducing buffer queue, the performance of the users can be improved, such as the blocking probability of the user can be reduced. By introducing priority to the buffer queue, the system can meet the particular users'requirements, and can satisfy different types of users'needs.