Analysis of the PRP M/G/1 queuing system for cognitive radio networks with handoff management

In this paper, the effect of multiple spectrum handoffs on data delivery time of Secondary Users (SU) in Cognitive Radio (CR) networks are investigated. Whenever a Primary User (PU) appears on a licensed channel, the spectrum handoff procedure is initiated to interrupt the SU and the channel must be released for PU´s transmission. In this paper, the rate of handoff occurrence is investigated and the preemptive resume priority (PRP) M/G/1 queuing model is used to characterized the multiple handoff and data delivery time of SU. In this paper, when spectrum handoff occurs during the transmission of a SU´s packet, the SU stops the transmission and this packet takes the higher priority rather than other SU´s packets and when the PU´s transmission is finished, this interrupted packet has higher priority to transmit. In fact, there are three classes of priority in this model. The highest priority is for PU´s packets, the next priority is for interrupted packets, and the last priority is for normal packets of SU. In fact, the second priority queue is a feedback queue that interrupted packets return to this queue. In order to support the stability conditions of the system, by considering the effect of multiple interruptions on data delivery time of SUs, we study the stability region for arrival rate of SUs in this paper. The simulation results show the rate of handoff occurrence based on analytical and simulation results, and also show the stability region for SU´s arrival rate considering handoff effects.