Robust Transmit Power Control in Cognitive Radio Using Genetic Algorithm
Abstract: A cognitive radio (CR) network is a multiuser system. Cognitive users(CU) compete for limited resources in an opportunistic manner by interacting with each other for access to the available resources. In CR networks, proper power controlling is important to ensure efficient operation of both primary and cognitive users. In this paper, an algorithm is used to dynamically control transmission power, which is capable of achieving reasonably good solutions fast enough in order to guarantee an acceptable level of performance for CU without degrading the performance of primary user(s). Genetic Algorithm is used to enhance the convergence time.
Keywords: Cognitive radio, Genetic Algorithm, Power allocation, Quality of Service.
I. INTRODUCTION
The recent rapid growth of wireless communications has made the problem of spectrum utilization ever more critical. On one hand, the increasing diversity (voice, short message, Web and multimedia) and demand of high quality-of-service (QoS) applications have resulted in overcrowding of the allocated (officially sanctioned) spectrum bands, leading to significantly reduced levels of user satisfaction. The problem is particularly serious in communication intensive situations such as after a ball-game or in a massive emergency (e.g.,the9/11attacks).On the other hand, major licensed bands, such as those allocated for television broadcasting, amateur radio, and paging, have been found to be grossly underutilized, resulting in spectrum wastage. For example, recent studies by the Federal Communications Commission (FCC) show that the spectrum utilization in the 0–6GHz band varies from 15% to 85% [1]. This has prompted the FCC to propose the opening of licensed bands to unlicensed users and given birth to cognitive radio [2].
In this technology, cognitive (unlicensed)user(CU) is not assigned to any frequency band in advance, but are allowed to have opportunistic access to idle spectrums or to the busy ones without
Abstract: A cognitive radio (CR) network is a multiuser system. Cognitive users(CU) compete for limited resources in an opportunistic manner by interacting with each other for access to the available resources. In CR networks, proper power controlling is important to ensure efficient operation of both primary and cognitive users. In this paper, an algorithm is used to dynamically control transmission power, which is capable of achieving reasonably good solutions fast enough in order to guarantee an acceptable level of performance for CU without degrading the performance of primary user(s). Genetic Algorithm is used to enhance the convergence time.
Keywords: Cognitive radio, Genetic Algorithm, Power allocation, Quality of Service.
I. INTRODUCTION
The recent rapid growth of wireless communications has made the problem of spectrum utilization ever more critical. On one hand, the increasing diversity (voice, short message, Web and multimedia) and demand of high quality-of-service (QoS) applications have resulted in overcrowding of the allocated (officially sanctioned) spectrum bands, leading to significantly reduced levels of user satisfaction. The problem is particularly serious in communication intensive situations such as after a ball-game or in a massive emergency (e.g.,the9/11attacks).On the other hand, major licensed bands, such as those allocated for television broadcasting, amateur radio, and paging, have been found to be grossly underutilized, resulting in spectrum wastage. For example, recent studies by the Federal Communications Commission (FCC) show that the spectrum utilization in the 0–6GHz band varies from 15% to 85% [1]. This has prompted the FCC to propose the opening of licensed bands to unlicensed users and given birth to cognitive radio [2].
In this technology, cognitive (unlicensed)user(CU) is not assigned to any frequency band in advance, but are allowed to have opportunistic access to idle spectrums or to the busy ones without
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