Achievable Rates for the Fading Half-Duplex Single Relay Selection Network Using Buffer-Aided Relaying

TL;DR

This paper introduces new buffer-aided relaying protocols for half-duplex single relay networks that achieve higher average rates than existing methods, while also addressing delay constraints and practical implementation considerations.

Contribution

The paper proposes novel buffer-aided relaying protocols that improve achievable rates and incorporate delay limitations without increasing channel information requirements.

Findings

Achievable rates surpass existing benchmarks.

Buffer-aided protocols with delay control are feasible.

Implementation does not require additional channel information.

Abstract

In the half-duplex single relay selection network, comprised of a source, $M$ half-duplex relays, and a destination, only one relay is active at any given time, i.e., only one relay receives or transmits, and the other relays are inactive, i.e., they do not receive nor transmit. The capacity of this network, when all links are affected by independent slow time-continuous fading and additive white Gaussian noise (AWGN), is still unknown, and only achievable average rates have been reported in the literature so far. In this paper, we present new achievable average rates for this network which are larger than the best known average rates. These new average rates are achieved with a buffer-aided relaying protocol. Since the developed buffer-aided protocol introduces unbounded delay, we also devise a buffer-aided protocol which limits the delay at the expense of a decrease in rate. Moreover, we discuss the practical implementation of the proposed buffer-aided relaying protocols and show that they do not require more resources for channel state information acquisition than the existing relay selection protocols.