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Peng Huang [1,2; ] and Feng Lin [3] and Jiliu Zhou [3]

Academic Editor: Tingwen Huang

, 1, , College of Electronics and Information Engineering, , Sichuan University, , Chengdu 610065, , China, , scu.edu.cn,

, 2, , School of Automotive and Electronic Engineering, , Xichang College, , Xichang 615000, , China,

, 3, , School of Computer Science, , Sichuan University, , Chengdu 610065, , China, , scu.edu.cn,

This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

1. Introduction

According to a report by FCC in 2002, average utilization of many spectrum bands allocated through static assignment polices varies between 15% and 85% [1]. In order to improve the utilization efficiency of existing radio spectrum, so-called Cognitive Radio (CR) has emerged as a technique which allows unlicensed secondary users (SUs) to access the licensed spectrum when no licensed primary users (PUs) appear on the frequency band. Primary users use traditional wireless communication system with static spectrum allocation while secondary users use CRs to complete communication through spectrum opportunities without interfering with Pus activities. With CRs, the efficiency in spectrum utilization will be improved significantly [2].

In realizing Cognitive Radio Networks (CRNs), both occupied spectrum and participating nodes of an abstract wireless link are opportunistically determined by their instantaneous availabilities. To fully explore the potentials of CRNs, it is important to study routing in dynamic spectrum access system while considering the unique properties of cognitive environment. Routing in cognitive radio networks shows characteristics different from traditional network and there are important differences in research methods. Due to characteristics of dynamic spectrum access, CR nodes channel changes with time and space. The quick changing channels and PUs interferences will lead to route instability. Therefore, most existing routing algorithms could not work well in CRNs. In this paper, we focus on the local spectrum knowledge scenario of multihop CRNs. We propose a framework of spectrum aware on-demand routing based on ant colony optimization, which could find the globe optimal path with minimum end-to-end delay and max delivery rate. The main contributions of this paper are listed as follows.

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A distributed, on-demand, optimal dynamic multihop routing...

  

 

 

 

 

 

 

 

      

 

  

 

 

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