Probabilistic and Transform Analyses of Amplify-And-Forward Wireless Relaying

  • Author / Creator
    Soliman, Samy Soliman Shokry Botros
  • Wireless cooperative networks have recently attracted the attention of many researchers as well as industry because such networks promise large diversity gains and increased capacity compared to other wireless communication systems. Accurate performance analysis of wireless cooperative systems is now important, since it enables the design of wireless communication systems with enhanced performance. The thesis focuses on two main categories of systems: dual-hop amplify-and-forward (AF) relaying systems and multihop AF relaying systems. For dual-hop AF systems, general probabilistic analysis is developed to obtain novel, exact analytical expressions for the probability density function (PDF) and the cumulative distribution function (CDF) of the instantaneous end-to-end signal-to-noise ratio (SNR) of variable gain AF relaying systems operating over Rayleigh, Nakagami- extit{m} and Rician fading channels, as well as asymmetric systems operating over mixed Nakagami- extit{m} and Rician fading links. Performance metrics, such as the average symbol error probability, outage probability and ergodic capacity, are calculated using the derived PDF and CDF expressions. Dual-hop AF systems under adaptive power transmission are also studied and closed-form expressions for the ergodic capacity of such systems are obtained. Dual-hop AF systems with relay selection are also analyzed and various techniques of relay selection are considered. This probabilistic analysis permits the comparison of dual-hop AF systems with different relay selection criteria, and leads to the factors that should be considered in designing such systems. For multihop AF systems, the generalized transformed characteristic function (GTCF) methods are proposed. The GTCF methods are new transform methods that constitute a general framework for exact analysis of generic multihop cooperative relaying systems. This framework is valid for any modulation scheme, any fading channel distribution and any number of relays. The GTCF method is used in the thesis to obtain exact solutions for the ergodic capacity, outage probability and the average symbol error probability of multihop AF relaying systems. A strength of the GTCF approach is that it can be used with tractable computational effort. The thesis shows the cases where the strength of the GTCF method is paramount, and identifies as well the cases where the use of the GTCF method is not recommended. The thesis also studies the effects of the numbers of hops, as well as the parameters of the fading channels on the system performance in multihop AF relaying. The GTCF methods are also used to analyze multi-branch multihop AF systems, obtain exact performance metrics of such systems and study the effects of the numbers of branches as well as the numbers of relays per branch on performance metrics of these systems. Finally, dual-hop AF systems with relay selection are compared to multihop AF systems, through studying the dependence of the performance metrics on the numbers of relays and the links’ fading parameters. The purpose of this comparison is to identify the strengths and weaknesses of multihop AF configurations as opposed to relay selection in dual-hop AF configurations. As a result of this comparison, system design criteria are proposed.

  • Subjects / Keywords
  • Graduation date
    Fall 2014
  • Type of Item
  • Degree
    Doctor of Philosophy
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.