This paper considers a modified Erlang loss system for cognitive wireless networks and related applications. A primary user has preemptive priority over secondary users and the primary customer is lost if upon arrival all the channels are used by other primary users. Secondary users cognitively use idle channels and they can wait at an infinite buffer in cases idle channels are not available upon arrival or they are interrupted by primary users. We obtain explicit stability condition for the cases where arrival processes of primary users and secondary users follow Poisson processes and their service times follow two distinct arbitrary distributions. The stability condition is insensitive to the service time distributions and implies the maximal throughout of secondary users. For a special case of exponential service time distributions, we analyze in depth to show the effect of parameters on the delay performance and the mean number of interruptions of secondary users. Our simulations for distributions rather than exponential reveal that the mean number of terminations for secondary users is less sensitive to the service time distribution of primary users.

中文翻译：

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用于认知无线网络的改进的Erlang丢失系统

本文考虑了一种用于认知无线网络及其相关应用的改进的Erlang损失系统。主要用户优先于次要用户，如果所有通道都被其他主要用户使用，则主要用户将丢失。次要用户在认知上使用空闲信道，并且在空闲信道到达时不可用或被主要用户打断的情况下，他们可以在无限缓冲区中等待。对于主要用户和次要用户的到达过程遵循泊松过程并且其服务时间遵循两个不同的任意分布的情况，我们获得了明确的稳定性条件。稳定性条件对服务时间分布不敏感，并且在整个二级用户中都表示最大。对于指数服务时间分布的特殊情况，我们进行了深入分析，以显示参数对二级用户的延迟性能和平均中断次数的影响。我们对分布而不是指数的模拟表明，次要用户的平均终止次数对主要用户的服务时间分布不太敏感。