Date of Graduation

2017

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Lane Department of Computer Science and Electrical Engineering

Committee Chair

Matthew C Valenti

Committee Co-Chair

Daryl S Reynolds

Committee Member

Brian D Woerner

Abstract

This thesis examines wireless relay networks that use hybrid-ARQ protocols. Relays networks efficiently combat fading and exploit the spatial diversity present in the channel. Hybrid-ARQ involves retransmitting the signal if it is not decoded correctly. In conventional HARQ, the retransmission comes from the source, but in cooperative HARQ the retransmission could come from a relay that has successfully decoded the message, thus attaining transmit diversity.;A Markov chain model is conceived and used to compute the effective throughput and outage probability in the presence of Rayleigh fading. The analytical results are validated with simulations. The spatial configuration of the network plays an important role in the performance of the network. The behavior of the protocols for fixed network topologies and random topologies is examined. The impact of parameters such as path loss exponent, number of relays, and Signal to Noise Ratio are determined.;Spatial averaging is helpful in capturing the spatial variations present in the system. When network topology is random, the analysis proceeds by first assuming the number of relays is fixed, in which case they are drawn from a Binomial Point Process (BPP). For each network realization, the outage probability, throughput and effective throughput are found, and the spatial average of these quantities are found by averaging over a large number of network realizations. Moreover, the maximum throughput is found for each network realization, leading to a characterization of the distribution of throughputs achievable in a random network. Finally, networks with a random number of relays are considered, including the important case that the number of relays in a given area is Poisson distributed, in which case they are drawn from a Poisson Point Process (PPP).

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