Uplink Energy-Delay Trade-off under Optimized Relay Placement in Cellular Networks

TL;DR

This paper explores how optimized relay node placement in cellular networks can significantly reduce uplink energy consumption while maintaining a minimum user delay, using a novel evaluation framework and simulated annealing optimization.

Contribution

It introduces a new framework for evaluating uplink relay networks and demonstrates an effective optimization method for relay placement considering energy and delay trade-offs.

Findings

Relay deployment improves uplink energy efficiency across various traffic conditions.

Relays are especially effective in non-uniform traffic scenarios.

Optimized relay placement balances energy savings with delay constraints.

Abstract

Relay nodes-enhanced architectures are deemed a viable solution to enhance coverage and capacity of nowadays cellular networks. Besides a number of desirable features, these architectures reduce the average distance between users and network nodes, thus allowing for battery savings for users transmitting on the uplink. In this paper, we investigate the extent of these savings, by optimizing relay nodes deployment in terms of uplink energy consumption per transmitted bit, while taking into account a minimum uplink average user delay that has to be guaranteed. A novel performance evaluation framework for uplink relay networks is first proposed to study this energy-delay trade-off. A simulated annealing is then run to find an optimized relay placement solution under a delay constraint; exterior penalty functions are used in order to deal with a difficult energy landscape, in particular when the constraint is tight. Finally, results show that relay nodes deployment consistently improve users uplink energy efficiency, under a wide range of traffic conditions and that relays are particularly efficient in non-uniform traffic scenarios.