期刊名称：International Journal of Future Generation Communication and Networking
印刷版ISSN：2233-7857
出版年度：2013
卷号：6
期号：4
出版社：SERSC
摘要：In this paper, we present a dynamic spectrum access strategy to reduce the average overall system time of secondary users (SUs) in multi-channel cognitive radio networks. Before transmitting a packet, SU senses the spectrum environment. If there are free channels in the system, SU randomly selects one for transmitting. If all the channels are busy, we consider a probability-based spectrum selection scheme in which the access channel is chosen based on the predetermined probabilities for saving the sensing power and reducing the overall system time of SU. When the transmission of SU is preempted by the primary user (PU), SU will stay on the operating channel and retransmit the whole data after PU leaves the channel. SU may undergo multiple interruptions before finishing a successful transmission. The interruptions and retransmissions inevitably increase the overall system time of SU. We propose an analytical model by applying the preemptive repeat identical priority M/G/1 queueing theory. Based on the model, we obtain the overall system time expression of SU packets under different spectrum environment and find the optimal distribution vector for the probability-based spectrum access scheme to minimize the average overall system time for SU.
关键词：Cognitive radio; dynamic spectrum access; overall system time; queueing theory.
