TY  - JOUR
T1  - Low-Complexity RTT Estimation Algorithm Using 5G NR PRACH
AU  - Choi, Suyong 
AU  - Kim, Junseong 
AU  - Back, Sungyeol 
AU  - Oh, Wangrok 
JO  - The Journal of Korean Institute of Communications and Information Sciences
PY  - 2022
DA  - 2022/1/15
DO  - 10.7840/kics.2022.47.2.221
KW  - 5G NR
KW  - PRACH
AB  - In a 5G NR (new radio) system, UEs (user equipments) transmit a PRACH (physical random access channel) preamble which is consist of a Zadoff-Chu (ZC) sequence to request uplink resource allocation to the dedicated base station. The base station estimates a power delay profile (PDP) by correlating the received PRACH preamble from the UE with a local reference signal. From the derived PDP, the base station can not only detect the PRACH but also estimate a round trip time (RTT) of the UE. For proper operation of PRACH, the length of CP (cyclic prefix) should be designed to be longer than the sum of the maximum possible RTT in the cell and the delay spread of multipath channel. In this case, the PDP from all possible UEs would be in the CP interval. Hence, it is sufficient to derive partial correlation for CP duration between the received signal and the reference signal. In this paper, we propose a new RTT estimation scheme requiring less complexity. The proposed RTT estimation scheme not only offers a better performance but also requires less complexity compared to the conventional scheme.