认知无线电频谱切换目标信道访问机制

针对认知无线电先应式决策频谱切换，该文提出按照信道平均空闲时间递减的顺序对目标信道进行访问的机制，证明了该机制在主用户信道空闲时间服从均匀分布、Rayleigh分布以及Weibull分布下均能够保证频谱切换失败概率最小。仿真结果表明所提机制得到的频谱切换失败概率要远远小于随机访问机制的切换失败概率。另外，当能够获得数十次信道空闲时间观测样本情况下，虽然存在估计误差，但所得频谱切换失败概率与理想最优频谱切换失败概率非常接近。

Target Channel Visiting Scheme for Spectrum Handoff in Cognitive Radio

A target channel visiting scheme which visits target channels in a descending order of channel mean vacant time duration is proposed for proactive decision spectrum handoff in cognitive radio.It proofs that this scheme result in minimum probability of handoff failure when the channel vacant time duration follows uniform distribution,Rayleigh distribution or Weibull distribution.Simulations show that the probability of handoff failure of this scheme is far lower than that of the random target channel visiting scheme.Moreover,when tens of samples of channel vacant time duration can be obtained,even though there is estimation error,the probability of handoff failure of the proposed scheme is very close to the optimal minimum probability.