Strategies to meet the configured repetitions in URLLC Uplink grant-free transmission

Le, Trung-Kien; Salim, Umer; Kaltenberger, Florian
ISWCS 2019, 16th International Symposium on Wireless Communication Systems, 27-30 August 2019, Oulu, Finland

In Ultra-Reliable Low-Latency Communication (URLLC), the user (UE) can be configured to transmit in grant-free/configured-grant (GF/CG) resources for uplink (UL) transmission that does not require the UE to transmit scheduling request (SR) and receive UL grant to reduce latency. In addition, the UE is also configured to transmit automatically a specific number of repetitions without waiting feedback. However, these
repetitions are only allowed to carry out in an interval with period P to avoid identity (ID) confusion in a Hybrid automatic repeat request (HARQ) process. Thereby, there is a chance that the UE cannot transmit all repetitions as configured if data arrives late
and it leads to a drop of reliability. Two approaches are proposed in this paper to cope with this problem. This first approach requires an usage of the explicit HARQ feedback structure and the second one is related to an additional SR transmitted by the
UE in parallel with data. The numerical results show the benefit of these two methods in increasing system performance in case of less configured repetitions made when they help the system to avoid or reduce packet loss due to Demodulation Reference
Signal (DMRS) miss-detection.

DOI
Type:
Conférence
City:
Istanbul
Date:
2019-08-27
Department:
Systèmes de Communication
Eurecom Ref:
5960
Copyright:
© 2019 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.

PERMALINK : https://www.eurecom.fr/publication/5960