Energy-Aware Traffic Offloading for Green Heterogeneous Networks

TL;DR

This paper proposes energy-aware traffic offloading schemes for heterogeneous networks with renewable energy harvesting, optimizing user association, SBS activation, and power control to significantly reduce on-grid power consumption while maintaining QoS.

Contribution

It introduces a novel two-stage offloading scheme considering energy harvesting and SBS operation modes, with analytical power saving gains derived for the first time.

Findings

Achieves over 50% power saving compared to conventional schemes.

Provides closed-form SBS activation conditions and optimal offloading strategies.

Demonstrates effectiveness with simulations based on daily traffic and solar energy profiles.

Abstract

With small cell base stations (SBSs) densely deployed in addition to conventional macro base stations (MBSs), the heterogeneous cellular network (HCN) architecture can effectively boost network capacity. To support the huge power demand of HCNs, renewable energy harvesting technologies can be leveraged. In this paper, we aim to make efficient use of the harvested energy for on-grid power saving while satisfying the quality of service (QoS) requirement. To this end, energy-aware traffic offloading schemes are proposed, whereby user associations, ON-OFF states of SBSs, and power control are jointly optimized according to the statistical information of energy arrival and traffic load. Specifically, for the single SBS case, the power saving gain achieved by activating the SBS is derived in closed form, based on which the SBS activation condition and optimal traffic offloading amount are obtained. Furthermore, a two-stage energy-aware traffic offloading (TEATO) scheme is proposed for the multiple-SBS case, considering various operating characteristics of SBSs with different power sources. Simulation results demonstrate that the proposed scheme can achieve more than 50% power saving gain for typical daily traffic and solar energy profiles, compared with the conventional traffic offloading schemes.