Joint path and spectrum diversity in cognitive radio ad-hoc networks

Md Arafatur Rahman,Marcello Caleffi,Luigi Paura

doi:10.1186/1687-1499-2012-235

Abstract

The uncertain availability of the spectral resource imposes unique challenges in cognitive radio networks. One of the critical issues is to counteract the performance degradation experienced by cognitive users (CUs) due to the activity of primary users (PUs). Since the activity of PUs varies both in frequency and space domain, diversity techniques can represent an efficient way to address this issue. In this article, it is proposed to jointly exploit path and spectrum diversity for effective use of spectrum in cognitive radio ad-hoc networks (CRAHNs). By jointly exploiting both the diversities, CUs can switch dynamically to different paths and spectrum bands for communicating with each other in presence of frequency- and space-varying PU activity. This idea is adopted in a routing protocol, referred to as Dual Diversity Cognitive Ad-hoc Routing Protocol, and simulation results reveal the effectiveness of introducing joint path and spectrum diversity in CRAHNs.

Highlights

Cognitive radio (CR) paradigm proposes to enhance the spectrum efficiency by allowing unlicensed users, referred to as cognitive users (CUs), to utilize dynamically and opportunistically the spectrum assigned to the primary users (PUs) when it is temporarily not used
One of the critical issues in cognitive radio ad-hoc networks (CRAHNs) is to counteract the performance degradation experienced by CUs because of the activity of PUs
We propose to jointly exploit path and spectrum diversity to counteract the PU activity by exploiting local knowledge about network topology, i.e., by exploiting hop routing

Summary

Introduction

Cognitive radio (CR) paradigm proposes to enhance the spectrum efficiency by allowing unlicensed users, referred to as cognitive users (CUs), to utilize dynamically and opportunistically the spectrum assigned to the primary users (PUs) when it is temporarily not used. The main feature of D2CARP is to jointly exploit the path and spectrum diversity in routing This feature allows CUs to switch dynamically among different paths and channels accounting for the local route decisions during the data forwarding time. 2: if channel c is free from PU // D2CARP exploits spectrum diversity by establishing multi-channel reverse routes in RREQ phase (line 4 to 12). D2CARP exploits spectrum diversity by establishing multi-channel reverse routes in RREQ phase, as it is shown from line 4 to 12 in Algorithm 1. 20: P discards the RREP; D2CARP exploits spectrum diversity by establishing multi-channel forward routes in RREP phase, as it is shown from line 4 to 12 in Algorithm 2.

CAODV D2CARP

Conclusion