A Lyapunov Optimization Approach for Green Cellular Networks with Hybrid Energy Supplies

TL;DR

This paper introduces a low-complexity, Lyapunov optimization-based online algorithm for hybrid energy supply cellular networks, effectively balancing grid energy use and QoS without prior statistical knowledge of energy or channel conditions.

Contribution

It proposes a novel, asymptotically optimal online algorithm for HES green cellular networks that minimizes long-term network service cost using only current system information.

Findings

The algorithm achieves near-optimal performance asymptotically.

It reduces computational complexity by solving a simple per-time slot problem.

Simulation results confirm the effectiveness and theoretical guarantees of the approach.

Abstract

Powering cellular networks with renewable energy sources via energy harvesting (EH) has recently been proposed as a promising solution for green networking. However, with intermittent and random energy arrivals, it is challenging to provide satisfactory quality of service (QoS) in EH networks. To enjoy the greenness brought by EH while overcoming the instability of the renewable energy sources, hybrid energy supply (HES) networks that are powered by both EH and the electric grid have emerged as a new paradigm for green communications. In this paper, we will propose new design methodologies for HES green cellular networks with the help of Lyapunov optimization techniques. The network service cost, which addresses both the grid energy consumption and achievable QoS, is adopted as the performance metric, and it is optimized via base station assignment and power control (BAPC). Our main contribution is a low-complexity online algorithm to minimize the long-term average network service cost, namely, the Lyapunov optimization-based BAPC (LBAPC) algorithm. One main advantage of this algorithm is that the decisions depend only on the instantaneous side information without requiring distribution information of channels and EH processes. To determine the network operation, we only need to solve a deterministic per-time slot problem, for which an efficient inner-outer optimization algorithm is proposed. Moreover, the proposed algorithm is shown to be asymptotically optimal via rigorous analysis. Finally, sample simulation results are presented to verify the theoretical analysis as well as validate the effectiveness of the proposed algorithm.