Title page for etd-0830112-160942


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URN etd-0830112-160942
Author Hao-Ting Yu
Author's Email Address No Public.
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Department Communications Engineering
Year 2011
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Lifetime Maximization of Secondary Cooperative Systems in Underlay Cognitive Radio Networks
Date of Defense 2012-07-30
Page Count 45
Keyword
  • relay selection
  • cognitive radio network
  • network lifetime
  • cooperative communication
  • Abstract In this thesis, we consider cognitive radio networks (CRN) combined with cooperative transmission, and investigate relay selection and power allocation strategies to maximize network lifetime (NLT). Cognitive radio network enhances spectrum efficiency resource by exploiting capabilities of cognition, learning and coordination against insufficient spectrum resource. In underlay cognitive radio network, however, transmitted energy of secondary user is constrained by interference level observed at primary user (PU). Though cooperation among secondary users (SU), multiple relays from virtual antenna array to improve transmission rate and reliability by exploiting spatial diversity. Most existing works assume that cooperative secondary users are plugged and with infinite energy device. In this thesis, we consider secondary cooperative systems where relays are battery-powered and with finite energy. We will investigate relay-selection schemes to reduce energy consumption of secondary relays and prolong network lifetime under the premises that secondary user’s transmission rate is guaranteed and interference constraint of primary user is met. Our major difference between this work and previous works is the definition of network lifetime, which is defined by the maximum duration that the probability of secondary user’s achievable rate below the guaranteed value, i.e. outage probability, is lower than a predetermined threshold. We proposed four relay-selection methods which take channel state information (CSI) and residual energy information (REI) into considerations to prolong network lifetime. Since the selection metrics of the proposed strategies requires CSI and REI of each individual relay, so the relay-selection can be accomplished in distributed manner through opportunistic sensing. No additional overhead is demanded for information exchange.
    Advisory Committee
  • Jyh-Horng Wen - chair
  • Chih-Peng Li - co-chair
  • Chao-Kai Wen - co-chair
  • Wen-Jen Huang - advisor
  • Files
  • etd-0830112-160942.pdf
  • indicate access worldwide
    Date of Submission 2012-08-30

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