Quality of Service Aware Channel Hopping Rendezvous in Cognitive Radio Networks for Internet of Things

Abstract

In the last few years, there has been significant growth in the number of smart wireless devices termed as Internet of Things (IoT). With the expansion in the number of IoT devices, the demand for wireless spectrum has also been increased tremendously while the spectrum is limited. Cognitive Radio Network (CRN) has emerged as a promising solution to the spectrum scarcity problem. In CRN, the unlicensed heterogeneous wireless devices have to dynamically make use of the spectrum which is not in use by the licensed users. However, establishing a common communication link between two heterogeneous wireless devices requires them to rendezvous on a commonly available channel which is a great challenge in a dynamic access environment. The time taken by two wireless devices to rendezvous on a commonly available channel is referred to as Time to Rendezvous (TTR). Depending upon Primary user (PU) temporal activity and required Quality of Service (QoS) by wireless devices, in this paper, we propose a novel QoS aware algorithm that can substantially reduce TTR of all the existing rendezvous algorithms. The algorithm takes into account the channel availability duration depending upon PU temporal activity and maximizes the utilization of these channels according to their availability duration. The algorithm works by reducing the number of channels to be hopped in the process of rendezvous. We develop a mathematical model to analyze the performance of the developed algorithm when applied to existing rendezvous algorithms. Both analytical and simulation results prove that the developed algorithm reduces the MTTR, increases the network throughput by providing required QoS to the wireless IoT devices and supports efficient utilization of wireless spectrum.