基于预测机制的认知无线电机会频谱接入

基于认知无线电(CR)的机会频谱接入技术，近年成为一个研究热点，但大部分文献是根据当前主用户的频谱活动情况来指导次用户的频谱接入。提出一种新的接入机制，根据主用户过去和现在的频谱活动来预测其未来的频谱活动，从而使次用户可以接入可用性高的频段，减少与主用户发生冲突碰撞的可能性。另外，门限值的设定更进一步减少了不可靠的频段，使次用户的通信质量得以提高。通过仿真实验可看出，与传统的接入机制以及未设门限值的接入机制相比较，所提方案能有效地减少主次用户之间的冲突碰撞率。

Forecast-based opportunistic spectrum access for cognitive radio networks

The opportunistic spectrum access (OSA) technology based on cognitive radio networks has recently become a research hotspot. However, most researchers put their focus on the current spectrum activity of primary users. This paper puts forward an access method based on the forecast mechanism. Accordingly, secondary users can access the channel with higher usability, thus reducing the conflicts between primary users and secondary users. Moreover, the designed threshold will further eliminate unreliable channel in order to improve the communication quality of secondary users. The mechanisms with the traditional one and the one without threshold were compared by simulation, which proves the improvement brought by the method in terms of conflict decrease.