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认知无线网络中合作频谱技术研究

作　者: 法来
导　师: 王芙蓉
学　校: 华中科技大学
专　业: 信息与通信工程
关键词: Cognitive Radio Spectrum Sensing Cooperative spectrum sensing noncooperative spectrum sensing Amplify-and-Forward algorithm Energy Detection
分类号: TN92
类　型: 硕士论文
年　份: 2009年
下　载: 13次
引　用: 0次
阅　读: 论文下载

内容摘要

Wireless networks technologies are on a rapid increase in demand nowadays. Wireless networks are characterized by fixed spectrum assignment policy that is imposed by FCC allowing more and more number of unlicensed users to transmit their signals in licensed bands so as to efficiently utilize the available spectrum due to the increasing demand for frequency spectrum and limited resource availability. Cognitive radios (CR) increase the efficiency of spectrum utilization (Quality of Service-QoS) through interference avoidance and local re-use of frequency bands originally designated for exclusive operation. Cognitive Radio can smartly senses and adapts with the changing environment by altering its transmitting parameters, such as modulation, frequency, frame format etc. The main challenges with cognitive radios are that it should not interfere with the licensed users and should vacate the band when required. These radios (CR) should be able to sense the signals at a very fast rate so as to make necessary decision whether to vacate or use the available spectrum. In this thesis, performance evaluation is done between cooperative and non cooperative spectrum sensing schemes which uses Amplify-and-Forward algorithm, agility gain, energy detection, hard and Soft decision rules in CR in order to evaluate the performance advantages of cooperation over non-cooperative Cognitive Radio networks .I tried to go a bit further to include another relay node at different relay time slot but the analysis of this scenario is not emphasized. Furthermore, based on the energy detection scheme OFDM system model was analyzed by placing a variable channel gain between the unlicensed users and the fusion center in vector notation.

全文目录

Abstract  5-6
Table of Contents  6-8
Abbreviations  8-9
List of Figures  9-10
List of Tables  10-11
Chapter 1  11-21
  1.1 Introduction  11-13
  1.2 Motivation and Background  13-17
  1.3 Research Objective  17
  1.4 Problem Statements  17
  1.5 Why Spectrum Sensing  17-18
  1.6 Thesis Outline  18-19
  1.7 Chapter Summary  19-21
Chapter 2 Spectrum Sensing Technologies  21-29
  2.1 Cognitive Radio Networks  21-22
  2.2 Directions of Cooperative Sensing  22-23
  2.3 Cluster Sensing  23-24
  2.4 Distributed Sensing  24-25
  2.5 Location Awareness  25-27
  2.6 Power Control  27-29
Chapter 3 Literature Review  29-38
  3.1 Spectrum Sensing  29-30
  3.2 Single User based detection  30
  3.3 Matched filter detector  30-31
  3.4 Cyclostationary feature detector  31-33
  3.5 Energy Detector  33-34
  3.6 Hypothesis model for Transmitter Detection  34-35
  3.7 Cooperation based detection Schemes  35-38
Chapter 4 Research Methodology  38-53
  4.1 Brief Summary  38
  4.2 Constrained Detection scheme  38-43
  4.3 Agility gain of Cognitive Users  43
  4.4 Cooperation Scheme for OFDM (Scalar Form)  43-48
  4.5 Decision Rule  48-49
  4.6 Cooperation Scheme for OFDM (Vector form)  49-53
Chapter 5 Simulation and Results Analysis  53-60
  5.1 Results on Cooperative detection Scheme (Constrained)  53-56
  5.2 Single&Multiple Carriers Sensing  56-57
  5.3 Cooperative Spectrum Sensing on OFDM (Vector form)  57-60
6.C onclusion  60-61
Acknowledgement  61-62
References  62-65

认知无线网络中合作频谱技术研究

内容摘要

全文目录

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