Outage Performance Of Relay Selection Research Articles

Relay selection in two-way full-duplex relay networks over Nakagami-m fading channels

We analyze the outage performance of relay selection in two-way full-duplex amplify-and-forward cooperative systems in the presence of residual loop-interference (LI) over Nakagami-m fading channels. In the proposed system, a relay node is selected according to max-min policy and the physical-layer-network-coding technique is applied for two-way transmission. By using end-to-end signal-to-interference-plus-noise-ratio, a new exact outage probability expression is derived in a single-integral form. The numerical and Monte-Carlo simulation results verify the analysis. Moreover, lower-bound and asymptotic expressions for the outage probability are obtained in closed-form. The numerical results reveal that the max-min selection policy provides a significant performance improvement for two-way full-duplex relaying. We observe that the outage performance can be enhanced as long as either the number of relay nodes, the transmit power, or the efficiency of the LI cancellation process increases.

Outage performance of relay selection with spatially random relays using RF energy harvesting

AbstractTo enable green wireless networks, one appealing approach is to deploy energy harvesting (EH) relays to assist the source transmission. Unlike conventional relays relying on fixed power supplies, EH relays make use of the energy collected from the RF radiation of the source node, and thus, they do not introduce extra energy cost to the network. This paper presents an analytical study to assess the efficacy of EH relays when the one with the maximal end‐to‐end signal‐to‐noise ratio is selected to perform data relaying while others perform EH. Because the action (either harvesting energy or forwarding data) of one EH relay affects those of others, exact performance analysis is not tractable. Additionally, relay density and positions may be random, which further complicates the analysis. Our analysis is conducted based on the hypothesis that each EH relay has an equal chance to be selected. This hypothesis allows for analytical tractability and is of importance to EH relays because otherwise some may drain their batteries fast. We identify the conditions under which the aforementioned hypothesis is valid. Our analysis also considers two variants of amplify‐and‐forward relays with and without using channel state information. Numerical results are presented to validate the analysis accuracy along with extensive discussions on the impact of numerous system parameters. Copyright © 2015 John Wiley & Sons, Ltd.