Abstract

Spectrum handoff is a very important phenomenon in Cognitive Radio (CR) networks. It provides flawless transmission upon the arrival of primary user (PU) while the channel is in use by the secondary user (SU). Spectrum handoff process provides the SUs with the opportunity to continue their communication on other unoccupied channels as soon as the PU repossesses its channel. FCC (Federal Communications Commission) has released new White Space rules in September 2010 which eliminate the requirement of spectrum sensing, making CRs more flexible. In addition, the CR is to be equipped with TV channel database. Taking these new rules into account, this paper suggests a new handoff scheme, HGCS (Handoff using Guard Channels Scheme), which makes effective use of the guard channels for communication. A preemptive resume priority (PRP) M/G/1 queuing network model is proposed to assess total service time for the suggested HGCS and comparing it to the existing random proactive-decision handoff scheme. Simulation and numerical results verify that HGCS can minimize the handoff delay, hence reduces the total service time compared to the random proactive approach.