US 11,910,339 B2
Methods and systems for uplink time synchronization in non-terrestrial networks based communication
Abhijeet Abhimanyu Masal, Chennai (IN); Priyanka Dey, Chennai (IN); Sunil Kaimalettu, Chennai (IN); Jeniston Deviraj Klutto Milleth, Chennai (IN); and Bhaskar Ramamurthi, Chennai (IN)
Assigned to CENTRE OF EXCELLENCE IN WIRELESS TECHNOLOGY, Chennai (IN); and INDIAN INSTITUTE OF TECHNOLOGY MADRAS (IIT MADRAS), Chennai (IN)
Filed by Centre of Excellence in Wireless Technology, Chennai (IN); and Indian Institute of Technology Madras (IIT Madras), Chennai (IN)
Filed on Oct. 22, 2021, as Appl. No. 17/451,952.
Claims priority of application No. 202041046349 (IN), filed on Oct. 23, 2020.
Prior Publication US 2022/0132447 A1, Apr. 28, 2022
Int. Cl. H04W 56/00 (2009.01); G01S 19/46 (2010.01); H04L 5/00 (2006.01); H04B 7/185 (2006.01)
CPC H04W 56/001 (2013.01) [G01S 19/46 (2013.01); H04B 7/18513 (2013.01); H04L 5/0048 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A method for performing Uplink (UL) time synchronization in a Non-Terrestrial Network (NTN) based communication network, the method comprising:
performing Downlink (DL) synchronization using Synchronization Signal Block (SSB) signals;
receiving, by a UE (102), at least one information from an NTN Base Station (BS) (104);
obtaining a location information of a satellite using the at least one information received by the UE (102);
estimating the location of the UE (102) using one of Global Navigation Satellite System (GNSS) receiver of the UE (102) and by processing at least one reference signal received by the UE (102) from multiple NTN BS (104), using at least one multilateration technique and Real-Time Kinematic (RTK);
determining Timing Advance (TA) estimate using the location of the satellite and location of the UE (102);
determining TA applied using the TA estimate and TA margin, wherein the TA margin is a value ranging from zero to a step size value (TAstep);
transmitting, by the UE (102), a Physical Random Access Channel (PRACH) based on the TA applied;
reporting, by the UE (102), an information related to the TA applied to the NTN-BS (104);
estimating, by the NTN-BS (104), residual TA using the reported information related to the TA applied and the detected PRACH and
indicating the residual TA to the UE (102) for subsequent UL transmissions, thereby achieving the UL time synchronization in the NTN based communication network.