# Joint Blocklength and Location Optimization for URLLC-enabled UAV Relay Systems

## TL;DR

This paper proposes a joint optimization of blocklength and UAV location in UAV relay systems to meet URLLC requirements, using a novel iterative algorithm that outperforms existing methods.

## Contribution

It introduces a perturbation-based iterative algorithm for joint blocklength and location optimization in UAV relay systems under URLLC constraints.

## Key findings

- The proposed algorithm achieves performance comparable to exhaustive search.
- It significantly outperforms existing algorithms in simulation.
- The method effectively minimizes decoding error probability under latency constraints.

## Abstract

This letter considers the unmanned aerial vehicle (UAV)-enabled relay system to deliver command information under ultra-reliable and low-latency communication (URLLC) requirements. We aim to jointly optimize the blocklength allocation and the UAV's location to minimize the decoding error probability subject to the latency requirement. The achievable data rate under finite blocklength regime is adopted. A novel perturbation-based iterative algorithm is proposed to solve this problem. Simulation results show that the proposed algorithm can achieve the same performance as the exhaustive search method, and significantly outperforms the existing algorithms.