Synchronization of uplink transmission from a user equipment (UE) in a non-terrestrial wireless network (NTN)

A user equipment (UE), comprising:

• a transceiver configured to enable wireless communication in a non-terrestrial wireless network (NTN);
• and
• a processor communicatively coupled to the transceiver and configured to:
• establish a communication connection with a base station in the NTN;
• determine whether global navigation satellite systems (GNSS) information is not available to the UE;
• in response to a determination that the GNSS information is not available, report to the base station that the GNSS information is not available;
• receive, from the base station, based on the reporting to the base station, an indication of one or more parameters for an uplink transmission from the UE to the base station, wherein the indication includes a timing drift rate of the UE for determination of a time advance for the uplink transmission, wherein the time advance is based on at least a product of the timing drift rate of the UE received from the base station and a time difference between two uplink transmissions from the UE to the base station;
• determine, based on a current transmission frequency and the received indication of the one or more parameters, a next transmission frequency;
• and
• transmit the uplink transmission at the determined next transmission frequency and based on the time advance.

A non-transitory computer-readable medium storing instructions that, when executed by a processor of a user equipment (UE), cause the UE to perform operations, the operations comprising:

• establishing a communication connection with a base station in a non-terrestrial wireless network (NTN);
• determining whether global navigation satellite systems (GNSS) information is not available to the UE;
• in response to a determination that the GNSS information is not available, reporting to the base station that the GNSS information is not available;
• receiving, from the base station, based on the reporting to the base station, an indication of one or more parameters for an uplink transmission from the UE to the base station, wherein the indication includes a timing drift rate of the UE for determination of a time advance for the uplink transmission, wherein the time advance is based on at least a product of the timing drift rate of the UE received from the base station and a time difference between two uplink transmissions from the UE to the base station;
• determining, based on a current transmission frequency and the received indication of the one or more parameters, a next transmission frequency;
• and
• transmitting the uplink transmission at the determined next transmission frequency and based on the time advance.