Queue Model Analysis for Spectrum-Sharing Cognitive Systems Under Outage Probability Constraint
This article investigates the behavior of the cognitive queueing system in a spectrum-sharing environment under the primary outage probability constraint. The queueing model is investigated under two cognitive transmit modes. A variable transmit rate that is equal to the cognitive channels capacity is first revisited, then the case of constant transmit rate is considered. Both transmit modes are found to lead to an \(M/G/1\) queueing model. The performance measures of the cognitive queue under these two modes are investigated and numerically compared. The performance measures include the mean transmit rate, mean service time, server utilization, mean waiting and transit times of the packets in the queue, mean number of waiting and transit packets in the queue, mean duration of the servers busy period, and mean number of packets served during the servers busy period. The effects of changing the primary outage probability constraint and the primary transmit rate on the performance measures are investigated as well.
outage probability channel capacity cognitive communications cross-layer design m/g/1 queue queue performance measures spectrum sharing