Efficient URLLC with a Reconfigurable Intelligent Surface and Imperfect Device Tracking
This work addresses reliability challenges in URLLC for wireless networks with RIS, but it is incremental as it builds on existing methods for handling positioning uncertainty.
The paper tackles the problem of Ultra-Reliable Low-Latency Communications (URLLC) with Reconfigurable Intelligent Surfaces (RIS) under imperfect device positioning, deriving an upper bound on outage probability and using it for power control to minimize power while meeting URLLC constraints, with an optimality gap of 1.5 to 4.5 dB.
The use of Reconfigurable Intelligent Surfaces (RIS) technology to extend coverage and allow for better control of the wireless environment has been proposed in several use cases, including Ultra-Reliable Low-Latency Communications (URLLC), communications. However, the extremely challenging latency constraint makes explicit channel estimation difficult, so positioning information is often used to configure the RIS and illuminate the receiver device. In this work, we analyze the effect of imperfections in the positioning information on the reliability, deriving an upper bound to the outage probability. We then use this bound to perform power control, efficiently finding the minimum power that respects the URLLC constraints under positioning uncertainty. The optimization is conservative, so that all points respect the URLLC constraints, and the bound is relatively tight, with an optimality gap between 1.5 and 4.5~dB.