Performance Evaluation for the Co-existence of eMBB and URLLC Networks: Synchronized versus Unsynchronized TDD

TL;DR

This paper assesses the performance of co-existing eMBB and URLLC networks in industrial settings, comparing synchronized and unsynchronized TDD configurations, and explores interference mitigation strategies for reliable factory automation communications.

Contribution

It provides a detailed simulation-based evaluation of co-existence scenarios, highlighting interference impacts and proposing channel isolation solutions for ultra-reliable low-latency communications.

Findings

Synchronized TDD causes high downlink interference reducing URLLC capacity.

Unsynchronized TDD reduces uplink URLLC capacity due to interference.

Adjacent channel allocation with proper isolation improves co-existence performance.

Abstract

To ensure the high level of automation required in today's industrial applications, next-generation wireless networks must enable real-time control and automation of dynamic processes with the requirements of extreme low-latency and ultra-reliable communications. In this paper, we provide a performance assessment for the co-existence of a macro (eMBB) and a local factory (URLLC) network and evaluate the network conditions under which the latency and reliability requirements of factory automation applications are met. In particular, we evaluate the co-existence of the eMBB and URLLC networks under two scenarios: (i) synchronized TDD, in which both networks follow the same TDD pattern, and (ii) unsynchronized TDD, in which the eMBB and URLLC networks follow different TDD patterns. Simulation results show that the high downlink interference from the macro base stations towards the factory results in a reduction of the downlink URLLC capacity and service availability in case of synchronized TDD and a reduction of the uplink URLLC capacity and service availability in case of unsynchronized TDD. Finally, it is shown that a promising case for co-existence is the adjacent channel allocation, for both synchronized and unsynchronized TDD deployments. Here, the required isolation to protect the URLLC network in the worst-case scenario where the factory is located next to a macro site can be handled via the factory wall penetration loss (e.g., considering high concrete or metal-coated building walls) along with other solutions such as filters, larger separation distance, and band pairing.