# Optimal Online Transmission Policy for Energy-Constrained Wireless-Powered Communication Networks

## TL;DR

This paper develops an optimal online transmission policy for energy-constrained wireless-powered communication networks, maximizing long-term throughput by formulating and solving a constrained Markov decision process.

## Contribution

It introduces a novel optimal policy for transmit power and time allocation using a Lagrangian approach, outperforming myopic strategies in various scenarios.

## Key findings

- Optimal policy significantly outperforms myopic policy.
- Power and time allocation are robust to modulation and coding changes.
- The policy effectively maximizes long-term throughput.

## Abstract

This work considers the design of online transmission policy in a wireless-powered communication system with a given energy budget. The system design objective is to maximize the long-term throughput of the system exploiting the energy storage capability at the wireless-powered node. We formulate the design problem as a constrained Markov decision process (CMDP) problem and obtain the optimal policy of transmit power and time allocation in each fading block via the Lagrangian approach. To investigate the system performance in different scenarios, numerical simulations are conducted with various system parameters. Our simulation results show that the optimal policy significantly outperforms a myopic policy which only maximizes the throughput in the current fading block. Moreover, the optimal allocation of transmit power and time is shown to be insensitive to the change of modulation and coding schemes, which facilitates its practical implementation.