Modified Erlang loss system for cognitive wireless networks

TL;DR

This paper introduces a modified Erlang loss model for cognitive wireless networks, providing explicit stability conditions, analyzing delay and interruption metrics, and demonstrating robustness of secondary user performance through simulations.

Contribution

It develops a stability condition insensitive to service time distributions and analyzes the impact of parameters on secondary user delay and interruptions.

Findings

Stability condition is insensitive to service time distributions.

Secondary user throughput is maximized under certain conditions.

Simulations show robustness of secondary user performance across distributions.

Abstract

This paper considers a modified Erlang loss system for cognitive wireless networks and related applications. A primary user has preemptive priority over secondary users and the primary customer is lost if upon arrival all the channels are used by other primary users. Secondary users cognitively use idle channels and they can wait at an infinite buffer in cases idle channels are not available upon arrival or they are interrupted by primary users. We obtain explicit stability condition for the cases where arrival processes of primary users and secondary users follow Poisson processes and their service times follow two distinct arbitrary distributions. The stability condition is insensitive to the service time distributions and implies the maximal throughout of secondary users. For a special case of exponential service time distributions, we analyze in depth to show the effect of parameters on the delay performance and the mean number of interruptions of secondary users. Our simulations for distributions rather than exponential reveal that the mean number of terminations for secondary users is less sensitive to the service time distribution of primary users.