Abstract
There is an extensive research interest in cognitive radio mobile ad hoc networks (CR-MANETs) to improve the spectrum efficiency by developing innovative design techniques through various layers of the protocol stacks. This paper presents the optimisation of CR-MANETs by exploiting the efficient usage of the available wireless spectrum through a framework for spectrum-aware handoff. In this paper, the concept of integrated handoff management in CR-MANETs is considered. An analytical model for a spectrum handoff scheme is introduced based on spectrum mobility in which secondary users (SUs) will move to another unused spectrum band, giving priority to a Primary User (PU), while satisfying its communication quality of service (QoS). The main contribution is using the Markov chain to model the evolution of the network (node position, node speed, channel quality, etc.) and to propose the combined spectrum handoff and routing. The performance of the network is analyzed based on the Markov chain. The comparison results from both analytical modelling and simulation clearly show an improvement in the performance of the SU network in terms of the route maintenance probability and the SU throughput. It is also proved that not only the PU activity affects the performance of the handoff management scheme but also the channel transmission range and the node mobility have a significant effect on the performance of the management scheme.
Highlights
There have been major changes in wireless technologies that demand more spectrum bands for allocation to emerging wireless applications
In the cognitive radio (CR) system, the shifting of the spectrum holes is defined as spectrum mobility, which is cohesive with spectrum handoff
The study reveals that the channel heterogeneity and secondary users (SUs)'s mobility must be considered as important factors, which affect the performance of the handoff management in the CR-MANETs
Summary
There have been major changes in wireless technologies that demand more spectrum bands for allocation to emerging wireless applications. To propose the integrated handoff management scheme, the availability of spectrum holes in CR-MANETs is considered. The proposed algorithm attempts to minimize the total link cost by taking into account the end-to-end network connectivity constraint Another major contribution of this paper was that the rerouting mechanism was performed before a spectrum handoff event to increase the system throughput. The study reveals that the channel heterogeneity and SU's mobility must be considered as important factors, which affect the performance of the handoff management in the CR-MANETs. As mentioned before, maintaining the optimal routes in CR-MANETs is extremely difficult because of the randomness of the PU's activity, the SU's mobility and the channel quality degradation. The results of both analytical modelling and proposed algorithm are compared to show the effectiveness of the proposed solution
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