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

1 . A method of performing wireless communication by a user equipment (UE), 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 that is different from the current transmission frequency; and

transmitting the uplink transmission at the determined next transmission frequency and based on the time advance.

2 . The method of claim 1 , further comprising:

reporting to the base station that the UE is a stationary UE;

reporting to the base station of a global navigation satellite systems (GNSS) location of the UE at an initial access stage that is configured when the stationary UE is initially installed; and

stopping the GNSS location tracking.

3 . The method of claim 1 , wherein the UE receives the indication of the one or more parameters periodically from the base station.

4 . The method of claim 1 , wherein the indication of the one or more parameters is contained in a medium access control (MAC) control element (CE) message, a downlink control indicator (DCI) message, a configured grant configuration message, or a radio resource control (RRC) configuration message.

5 . The method of claim 1 , wherein the indication of the one or more parameters includes a frequency offset for the UE to adjust to the next transmission frequency from the current transmission frequency.

6 . The method of claim 5 , wherein the frequency offset between the current transmission frequency and the next transmission frequency is a relative frequency offset equal to one or more of a basic offset Y.

7 . The method of claim 5 , wherein the frequency offset is an absolute frequency offset equal to one or more of a basic offset Y.

8 . The method of claim 5 , wherein the frequency offset is related to a frequency drifting rate and a time difference between two uplink transmissions.

9 . The method of claim 1 , wherein the indication of the one or more parameters is contained in a configured grant configuration message, and the indication of the one or more parameters includes a frequency offset for the UE to adjust to the next transmission frequency from the current transmission frequency for multiple uplink transmissions.

10 . The method of claim 1 , wherein the non-terrestrial wireless network includes a satellite, and the base station is in communication with a transceiver located on the satellite.

11 . 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.

12 . The UE of claim 11 , wherein the processor is further configured to:

report to the base station that the UE is a stationary UE;

report to the base station of a global navigation satellite systems (GNSS) location of the UE at an initial access stage that is configured when the stationary UE is initially installed; and

stop the GNSS location tracking.

13 . The UE of claim 11 , wherein the UE receives the indication of the one or more parameters periodically from the base station.

14 . The UE of claim 11 , wherein the indication of the one or more parameters is contained in a medium access control (MAC) control element (CE) message, a downlink control indicator (DCI) message, a configured grant configuration message, or a radio resource control (RRC) configuration message.

15 . The UE of claim 11 , wherein the indication of the one or more parameters includes a frequency offset for the UE to adjust to the next transmission frequency from the current transmission frequency.

16 . The UE of claim 15 , wherein the frequency offset between the current transmission frequency and the next transmission frequency is a relative frequency offset equal to one or more of a basic offset Y.

17 . 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.

18 . The non-transitory computer-readable medium of claim 17 , wherein the indication of the one or more parameters is contained in a medium access control (MAC) control element (CE) message, a downlink control indicator (DCI) message, a configured grant configuration message, or a radio resource control (RRC) configuration message.