Performance Analysis of a Slotted Multi-Channel MAC Protocols for Cognitive Radio Networks
Cognitive radio has emerged as one of effctive methods to enhance utilization of radio spectrum. Main principle of cognitive radio is that the secondary users (SUs) are allowed to use the spectrum not used by primary users (PUs) without interfering PUs transmission. In this paper,we consider network system where PUs use channels under super-slot time structure and SUs content to access channels during unused super-slot so as not to interfere PUs transmission. For contention resolution,super-slot is divided into slots of fixed size which are used as backoff unit for backoff algorithm. For contending SUs,our proposed MAC protocol operates by the following modiffed CSMA/CA with binary backoff algorithm: Each SU uniformly chooses a backoff counter from the current backoff window. The backoff counter in dicates the number of slots that the station has to wait be fore the transmission. At the beginning of super-slot,SU senses pre-determined number of channels. If there are no idle channels,then the backoff counter of the SU is frozen during a current super-slot duration. If there are idle chan nels,then the SU decrements its backoff counter by one per each time slot as long as time slot is idle. When the backoff counter of the SU reaches zero,the SU transmits the packets as many of foxed size as idle channels accommodate in the current super-slot. During backoff procedure of the SU,if other SUs occupy the remaining idle channels,back off counter of the SU is frozen during the remaining part of super-slot and is reactivated when at least one channel is sensed idle at the beginning of the super-slot. We construct the three-dimensional discrete time Markov chain (DTMC) to investigate the performance of the proposed multi-channel MAC protocol and we obtain stationary probability vector of DTMC by censored Markov chains method. Then,using the stationary probability vector of DTMC,we obtain the head of line (HoL) packet delay distribution and the normalized throughput of SUs.
censored Markov chain cognitive radio multi-channel MAC protocol performance analysis
Kyung Jae Kim Jin Soo Park Yun Han Bae Bong Dae Choi
Department of Mathematics, Korea University,Seoul,Korea Convergence Technology Department,Central R&D Laboratories,KT,Seoul,Korea Department of Mathematics,Korea University,Seoul,Korea
国际会议
北京
英文
51-58
2010-07-24（万方平台首次上网日期，不代表论文的发表时间）