Buffer‐aided relaying for the multi‐user uplink: outage analysis and power allocation

Abstract

In this study, the authors consider a two-hop network, where multiple source nodes (SNs) transmit to a destination node (DN) with the aid of a relay node (RN). The RN is equipped with a buffer, which is capable of storing multiple frames received from the SNs. During each time slot, the proposed protocol activates either the SN–RN hop or the RN–DN hop, depending on the channel quality of each hop and the buffer state at the RN. To optimise the hop activation for the network, they design a hop quality metric and propose a multi-user buffer-aided-relaying uplink (MU-BR-UL) protocol, with the aid of the minimum signal-to-noise power ratio approximation. The benefits of the proposed protocol are analysed in terms of the end-to-end (e2e) outage probability and the e2e transmission delay. Then, the optimal power allocation is proposed for minimising the e2e outage probability under the total power constraint. The results indicate that the outage performance is significantly improved when the proposed power allocation is utilised in the MU-BR-UL protocol.