Research On Ultra-reliable Low-latency Communication Assisted By Drone Rela

Ultra-Reliable and Low-Latency Communications(u RLLC)play a critical role in applications such as Industrial Internet of Things,Connected Vehicles,Intelligent Transportation Systems,and Remote Healthcare,where high reliability and low latency are essential.However,the presence of path loss,shadowing,and multipath fading poses significant challenges in meeting the stringent requirements of u RLLC.Unmanned Aerial Vehicle(UAV)have advantages such as low cost and high mobility,allowing them to be deployed on-demand based on application scenarios.UAVs can establish Line-of-Sight(Lo S)links with ground nodes with high probability,improving channel quality and effectively meeting the network’s reliability and latency requirements when Lo S links cannot be established between distant ground nodes.This paper focuses on the u RLLC scenario and constructs a system model for UAV-assisted u RLLC,taking into account the reliability and latency requirements of u RLLC and the channel characteristics of UAV communication.The paper investigates resource optimization problems in UAV-assisted u RLLC scenarios.The main research contents are as follows:(1)Single UAV relay assisted u RLLC system analysis and research.The channel model and decoding error probability model between UAV relay and ground equipment are constructed.With the goal of minimizing decoding error probability,the joint optimization problem of UAV relay deployment location and system power allocation is studied.Because the optimization problem is non-convex and difficult to be solved directly,the joint optimization problem is transformed into SNR optimization problem by mathematical analysis of decoding error probability expression,and an algorithm based on block coordinate descent is proposed to decompose the optimization problem into three subproblems: power distribution,UAV relay deployment height and UAV relay horizontal deployment location.The effectiveness of the proposed algorithm was validated through simulation experiments,and it was demonstrated through comparisons with fixed resource allocation and single optimization schemes that joint optimization can significantly reduce decoding error probability.(2)Multiple hops UAV relay assisted u RLLC system resources optimization research.Considering the limitation of single UAV coverage,this paper studied the joint optimization problem of transmission time slot division and UAV relay deployment location in order to minimize the total decoding error probability.In this paper,the joint optimization problem is decomposed into two subproblems for iterative solution: for the time gap division problem,the convex analysis is carried out first,the mathematical properties are used to prove that the subproblem is convex optimization problem,and the convex optimization tool is used to solve the problem.A low complexity algorithm based on ant colony algorithm is proposed for UAV relay deployment.Finally,the simulation results show that the proposed algorithm can achieve similar performance to the exhaustive search algorithm with low time complexity.Meanwhile,a performance gain was observed in the joint optimization scheme compared to the fixed resource allocation scheme,which could achieve lower decoding error probability with the same system resources.