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无线通信势不可挡的增长趋势导致了无线电频谱的拥挤和匮乏。一方面,无线用户越发难以找到可用频段进行通信,另一方面,许多预先分配的频段却没有得到充分利用,白白浪费。为解决这个困难局面,认知无线电应运而生。在认知无线电模型下,主要有两个层级的用户:首要用户(PU),即得到许可且有权优先使用特定频谱的用户,往往需要稳定的频谱用于通信;次要用户(SU),则往往只需要短暂接入频谱,只在不影响首要用户的前提
The overwhelming growth of wireless communications has led to overcrowding and starvation of the radio spectrum. On the one hand, it becomes more difficult for wireless users to find available frequency bands for communication. On the other hand, many pre-allocated frequency bands have not been fully utilized and were wasted. To solve this difficult situation, cognitive radio came into being. Under the cognitive radio model, there are mainly two levels of users: primary users (PUs), that is, users who are licensed and entitled to prioritize specific spectrum often require stable spectrum for communication; secondary users (SUs) You often only need to briefly access the spectrum, only in the premise does not affect the primary user