Access performance analysis of MAC in CR network
Yang Xiao · Journal of Beijing Jiaotong University · 2012
The Primary Users(PUs) has the right to use the spectrum in CR(Cognitive Radio) network,the CR user will have to make way the using spectrum once detecting the PUs,which makes the MAC frame loss,the existing IEEE 802.11 DCF protocol can't solve above problem about the losing MAC frame in CR network,CR users will have to re-access when getting the spectrum again,which leads to bigger delay of spectrum handoff.To solve the delay of spectrum handoff,this paper increases freezing and buffer mechanism by modified the existing IEEE 802.11 DCF protocol for CR network.The modified DCF protocol can continue previous MAC frame rather than afresh access by freezing the backoff timer and preserving the current state in the buffer.The simulation results indicate that the modified DCF protocol can increase the throughput and decrease the delay of access during spectrum handoff,which improves the performance of DCF mechanism in CR network.