Multiuser Joint Energy-Bandwidth Allocation with Energy Harvesting - Part II: Multiple Broadcast Channels & Proportional Fairness

TL;DR

This paper develops efficient algorithms for energy and bandwidth allocation in multiuser energy-harvesting networks with multiple broadcast channels, optimizing throughput and fairness under orthogonal and non-orthogonal conditions.

Contribution

It introduces a novel iterative algorithm for joint energy-bandwidth allocation in complex broadcast channel settings with energy harvesting, including proportional fairness considerations.

Findings

Proposed algorithms achieve near-optimal throughput with reduced complexity.

Orthogonal broadcast channels perform comparably to non-orthogonal ones in energy-harvesting scenarios.

Significant performance improvements over heuristic policies are demonstrated through simulations.

Abstract

In this paper, we consider the energy-bandwidth allocation for a network with multiple broadcast channels, where the transmitters access the network orthogonally on the assigned frequency band and each transmitter communicates with multiple receivers orthogonally or non-orthogonally. We assume that the energy harvesting state and channel gain of each transmitter can be predicted for $K$ slots {\em a priori}. To maximize the weighted throughput, we formulate an optimization problem with $O(MK)$ constraints, where $M$ is the number of the receivers, and decompose it into the energy and bandwidth allocation subproblems. In order to use the iterative algorithm proposed in [1] to solve the problem, we propose efficient algorithms to solve the two subproblems, so that the optimal energy-bandwidth allocation can be obtained with an overall complexity of ${\cal O}(MK^2)$, even though the problem is non-convex when the broadcast channel is non-orthogonal. For the orthogonal broadcast channel, we further formulate a proportionally-fair (PF) throughput maximization problem and derive the equivalence conditions such that the optimal solution can be obtained by solving a weighted throughput maximization problem. Further, the algorithm to obtain the proper weights is proposed. Simulation results show that the proposed algorithm can make efficient use of the harvested energy and the available bandwidth, and achieve significantly better performance than some heuristic policies for energy and bandwidth allocation. Moreover, it is seen that with energy-harvesting transmitters, non-orthogonal broadcast offers limited gain over orthogonal broadcast.