Cellular-Connected UAVs over 5G: Deep Reinforcement Learning for Interference Management

TL;DR

This paper introduces a deep reinforcement learning approach using echo state networks for interference-aware path planning of cellular-connected UAVs, optimizing energy efficiency, latency, and interference management.

Contribution

It proposes a novel ESN-based deep reinforcement learning algorithm for UAV path planning that converges to a subgame perfect Nash equilibrium, reducing computational complexity.

Findings

The scheme improves wireless latency and user data rates.

Optimal UAV altitude depends on ground network density and data requirements.

The algorithm converges efficiently to a stable equilibrium.

Abstract

In this paper, an interference-aware path planning scheme for a network of cellular-connected unmanned aerial vehicles (UAVs) is proposed. In particular, each UAV aims at achieving a tradeoff between maximizing energy efficiency and minimizing both wireless latency and the interference level caused on the ground network along its path. The problem is cast as a dynamic game among UAVs. To solve this game, a deep reinforcement learning algorithm, based on echo state network (ESN) cells, is proposed. The introduced deep ESN architecture is trained to allow each UAV to map each observation of the network state to an action, with the goal of minimizing a sequence of time-dependent utility functions. Each UAV uses ESN to learn its optimal path, transmission power level, and cell association vector at different locations along its path. The proposed algorithm is shown to reach a subgame perfect Nash equilibrium (SPNE) upon convergence. Moreover, an upper and lower bound for the altitude of the UAVs is derived thus reducing the computational complexity of the proposed algorithm. Simulation results show that the proposed scheme achieves better wireless latency per UAV and rate per ground user (UE) while requiring a number of steps that is comparable to a heuristic baseline that considers moving via the shortest distance towards the corresponding destinations. The results also show that the optimal altitude of the UAVs varies based on the ground network density and the UE data rate requirements and plays a vital role in minimizing the interference level on the ground UEs as well as the wireless transmission delay of the UAV.