Soft-ACK Feedback Based Link Adaptation for Latency Critical Applications in 5G/B5G
József Németh, Mohammed Al-Imari, Waseem Ozan · 2021 IEEE Global Communications Conference (GLOBECOM) · 2021
Link adaptation plays an essential role in optimizing the performance of wireless communications systems. With the emerging services, link adaptation needs to operate with stringent reliability and latency requirements. This paper introduces soft-ACKINACK based link adaptation, which is an adaptation of conventional OLLA to the high reliability and low latency requirements by a range of emerging 5G/6G NR applications, such as URLLC/IIoT, AV/AR, cloud gaming or V2X. We study the limitations of conventional OLLA for these scenarios, and introduce an enhanced OLLA algorithm using soft-ACK/NACK feedback from the UE. We analyse the possible methods to derive soft-ACK/NACK reports, and propose using flipped bit counts based on accuracy and feasibility. The performance gains of soft-OLLA are assessed in performance simulations.