Robust Transmission Scheduling for UAV-assisted Millimeter-Wave Train-Ground Communication System

TL;DR

This paper introduces a UAV-assisted transmission scheduling algorithm for millimeter-wave train-ground communication systems, enhancing robustness against blockage and improving throughput in high-speed railway scenarios.

Contribution

It proposes the UMRA algorithm for UAV trajectory and transmission scheduling, addressing link blockage and optimizing system performance with a graph theory-based approach.

Findings

UMRA significantly increases the number of completed flows.

Optimal UAV positioning enhances system throughput.

UMRA outperforms benchmark schemes under high channel quality requirements.

Abstract

With the explosive growth of mobile data, the demand of high-speed railway (HSR) passengers for broadband wireless access services urgently needs the support of ultra-highspeed scenario broadband wireless communication. Millimeterwave (mmWave) can achieve high data transmission rates, but it is accompanied by high propagation loss and vulnerability to blockage. To address this issue, developments of directional antennas and unmanned aerial vehicles (UAVs) enhance the robustness of the mmWave train-ground communication system. In this paper, we propose a UAV and MRs relay assistance (UMRA) algorithm to effectively overcome link blockage, which can maximize the number of transmission flows on the premise of meeting QoS requirements and channel qualities. First, we formulate a mixed integer nonlinear programming (MINLP) problem for UAV trajectory design and transmission scheduling in the full-duplex (FD) mode. Then, in UMRA, the relay decision algorithm and transmission scheduling algorithm based on graph theory are proposed, which make a good tradeoff between computation complexity and system performance. Extensive simulation results show that a suitable UAV position will greatly improve the performance of the UMRA algorithm and make it close to the optimal solution. Compared with the other two existing benchmark schemes, with the high channel quality requirements and large-area blockage, UMRA can greatly improve the number of completed flows and system throughput.