Recently, cooperative diversity system has become an effective way to mitigate multipath fading. This thesis concentrates on the performance analysis of cooperative diversity relaying system by considering several realistic limitations. These limitations are likely to exist in the real network and may cause the system performance degradation significantly. Consequently, it is valuable to produce the more accurate system evaluation for the development of network. Our research work is immersed in amplify-and-forward (AF) relaying protocol due to its simplicity. The effect of limitations such as correlated channels, signal-to-noise ratio (SNR) estimation errors and feedback delay are further studied. At first, we analyze the performance of a single antenna dualhop AF relaying system with correlated links in Nakagami-m fading channels by taking account of blind fixed-gain relaying (BFG), semiblind fixed-gain relaying (SFG), and variable-gain relaying (VG) schemes. Numerical results show that the link correlation can have a considerable effect on these schemes for specific ways of correlation, especially when the correlation coefficient is larger than 0.5. Then we investigate the effect of SNR estimation error which assumes relay selection performed under imperfect channel gain as well as imperfect noise power in Rayleigh fading channels. The numerical derivations of outage probability together with PDF and CDF of the estimated end-to-end SNR are verified and analyzed by simulation results. Finally, regarding the impact of outdated channel state information (CSI) due to feedback delay, we evaluate the performances of several generalized relay selection schemes based on multihop cooperative diversity over Rayleigh fading channels. Our results show that increasing the hop index may lead different peformance degradations for different relay selection schemes. Furthermore, it is also shown that selecting more relays in one hop does not necessarily lead to better performance. Again, simulation results verify the correctness of numerical derivation of outage probability.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:595785 |
| Date | January 2014 |
| Creators | Shi, Rui |
| Publisher | University of Warwick |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://wrap.warwick.ac.uk/59812/ |
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