Voice Capacity of Cognitive Radio Networks for Both Centralized and Distributed Channel Access Control

As an emerging networking technology, cognitive radio networks (CRNs) have drawn immense attention in the wireless networking community. Since multimedia services have become widely popular among wireless communication services users, supporting those services over CRNs has become an interesting research topic in recent years. However, due to the random nature of the resource availability in CRNs, providing quality-of-service (QoS) guarantees for multimedia services is a challenging task. In this paper, we consider a secondary system operating over a time-slotted primary system and secondary users accessing the channels at the spectrum holes without interfering with primary users. As the capacity analysis is one of the basic steps to guarantee QoS, we analyze the constant-rate voice capacity of multi-channel fully-connected CRNs under different generic channel access schemes with centralized and distributed control, respectively. The capacity is represented in terms of the number of simultaneous independent voice calls that the secondary system can support, providing stochastic delay guarantee. It is shown that the analytical results closely match with the simulation results, and the number of voice packets that can be simultaneously transmitted in a time-slot per channel has a significant impact on the capacity of the system. With proper medium access control, capacity analysis can help to develop a call admission control policy for QoS provisioning in CRNs.