Joint Energy-Bandwidth Allocation for Multi-User Channels with Cooperating Hybrid Energy Nodes

TL;DR

This paper develops an optimization framework for joint energy and bandwidth allocation in multi-user networks with hybrid energy sources and energy cooperation, aiming to maximize throughput while balancing energy costs.

Contribution

It introduces a novel optimization model and an efficient iterative algorithm for joint energy-bandwidth allocation with energy cooperation in multi-user networks.

Findings

Efficient use of harvested and grid energy demonstrated.

Energy cooperation improves overall network throughput.

Proposed algorithm converges to optimal solution with manageable complexity.

Abstract

In this paper, we consider the energy-bandwidth allocation for a network of multiple users, where the transmitters each powered by both an energy harvester and conventional grid, access the network orthogonally on the assigned frequency band. We assume that the energy harvesting state and channel gain of each transmitter can be predicted for $K$ time slots a priori. The different transmitters can cooperate by donating energy to each other. The tradeoff among the weighted sum throughput, the use of grid energy, and the amount of energy cooperation is studied through an optimization objective which is a linear combination of these quantities. This leads to an optimization problem with O($N^2K$) constraints, where $N$ is the total number of transmitter-receiver pairs, and the optimization is over seven sets of variables that denote energy and bandwidth allocation, grid energy utilization, and energy cooperation. To solve the problem efficiently, an iterative algorithm is proposed using the Proximal Jacobian ADMM. The optimization sub-problems corresponding to Proximal Jacobian ADMM steps are solved in closed form. We show that this algorithm converges to the optimal solution with an overall complexity of O($N^2K^2$). Numerical results show that the proposed algorithms can make efficient use of the harvested energy, grid energy, energy cooperation, and the available bandwidth.