Granted Patent B2

US 12,550,091 · App. 18/552,702 · Granted Feb 10, 2026

Inventors: Abdelkader Medles (Cambridge, GB); Gilles Charbit (Hsinchu, GB)

Assignee: MEDIATEK SINGAPORE PTE. LTD.

H04W56/0045H04B7/01H04B7/18513

Abstract

Claims (66)

1 . A method, comprising:

obtaining, by a processor of an apparatus, a center frequency and a reference time of a non-terrestrial network (NTN);

obtaining, by the processor, a feeder link delay of a feeder link between a network node and a satellite;

obtaining, by the processor, a service link delay drift rate of a service link between the apparatus and the satellite; and

performing, by the processor, an uplink (UL) frequency pre-compensation through calculating an uplink transmit frequency according to the center frequency, the reference time, the feeder link delay, and the service link delay drift rate.

2 . The method of claim 1 , wherein a reception time at the satellite is calculated as subtracting the feeder link delay from the reference time.

3 . The method of claim 2 , further comprising:

calculating, by the processor, a Doppler frequency shift as the center frequency times the service link delay drift rate at the reception time; and

calculating, by the processor, the UL transmit frequency by subtracting the Doppler frequency shift from the center frequency.

4 . The method of claim 2 , further comprising:

measuring, by the processor, a received frequency of a downlink (DL) signal;

obtaining, by the processor, a service link delay;

obtaining, by the processor, a Doppler frequency drift rate;

calculating, by the processor, a Doppler frequency shift as the center frequency times the service link delay drift rate at the reception time;

calculating, by the processor, a Doppler frequency variation as the center frequency times the Doppler frequency drift rate times twice the service link delay; and

calculating, by the processor, the UL transmit frequency by subtracting twice the Doppler frequency shift from the received frequency and adding the Doppler frequency variation to the received frequency.

5 . The method of claim 1 , further comprising:

obtaining, by the processor, a common timing advance (TA); and

deriving, by the processor, the feeder link delay as half the common TA.

6 . The method of claim 1 , further comprising:

obtaining, by the processor, a common timing advance (TA);

obtaining, by the processor, a feeder link delay drift rate; and

adjusting, by the processor, a sampling rate according to the reference time, the common TA, the feeder link delay drift rate, and the service link delay drift rate.

7 . The method of claim 6 , further comprising:

performing, by the processor, a timing compensation through adjusting a baseband signal according to the common TA and the adjusted sampling rate.

8 . The method of claim 6 , wherein the feeder link delay drift rate is calculated by the processor based on an ephemeris of the satellite and a position of the network node or based on the common TA.

9 . The method of claim 6 , wherein the feeder link delay drift rate is calculated by the processor an ephemeris of the satellite and a position of the network node or based on the common TA.

10 . The method of claim 6 , further comprising:

receiving, by the processor, a close loop timing advance (TA) from the network node;

calculating, by the processor, a user equipment (UE) specific TA based on a position of the apparatus and an ephemeris of the satellite;

calculating, by the processor, the common TA based on the feeder link delay, the service link delay, the feeder link delay drift rate, and the reference time; and

calculating, by the processor, a transmit time for transmitting an uplink signal according to the close loop TA, the UE specific TA, and the common TA.

11 . An apparatus, comprising:

a transceiver configured to wirelessly communicate with a non-terrestrial network (NTN); and

a processor coupled to the transceiver and configured to perform operations comprising:

obtaining, via the transceiver, a center frequency and a reference time of a non-terrestrial network (NTN);

obtaining, via the transceiver, a feeder link delay of a feeder link between a network node and a satellite;

obtaining, via the transceiver, a service link delay drift rate of a service link between the apparatus and the satellite; and

performing an uplink (UL) frequency pre-compensation through calculating an uplink transmit frequency according to the center frequency, the reference time, the feeder link delay, and the service link delay drift rate.

12 . The apparatus of claim 11 , wherein a reception time at the satellite is calculated as subtracting the feeder link delay from the reference time.

13 . The apparatus of claim 12 , wherein the processor further performs operations comprising:

calculating a Doppler frequency shift as the center frequency times the service link delay drift rate at the reception time; and

calculating the UL transmit frequency by subtracting the Doppler frequency shift from the center frequency.

14 . The apparatus of claim 12 , wherein the processor further performs operations comprising:

measuring a received frequency of a downlink (DL) signal;

obtaining, via the transceiver, a service link delay;

obtaining a Doppler frequency drift rate;

calculating a Doppler frequency shift as the center frequency times the service link delay drift rate at the reception time;

calculating a Doppler frequency variation as the center frequency times the Doppler frequency drift rate times twice the service link delay; and

calculating the UL transmit frequency by subtracting twice the Doppler frequency shift from the received frequency and adding the Doppler frequency variation to the received frequency.

15 . The apparatus of claim 11 , wherein the processor further performs operations comprising:

obtaining, via the transceiver, a common timing advance (TA); and

deriving the feeder link delay as half the common TA.

16 . The apparatus of claim 11 , wherein the processor further performs operations comprising:

obtaining, via the transceiver, a common timing advance (TA);

obtaining, via the transceiver, a feeder link delay drift rate; and

adjusting a sampling rate according to the reference time, the common TA, the feeder link delay drift rate, and the service link delay drift rate.

17 . The apparatus of claim 16 , wherein the processor further performs operations comprising:

performing a timing compensation through adjusting a baseband signal according to the common TA and the adjusted sampling rate.

18 . The apparatus of claim 16 , wherein the feeder link delay drift rate is calculated by the processor based on an ephemeris of the satellite and a position of the network node or based on the common TA.

19 . The apparatus of claim 16 , wherein the feeder link delay drift rate is calculated by the processor an ephemeris of the satellite and a position of the network node or based on the common TA.

20 . The apparatus of claim 16 , wherein the processor further performs operations comprising:

receiving, via the transceiver, a close loop timing advance (TA) from the network node;

calculating a user equipment (UE) specific TA based on a position of the apparatus and an ephemeris of the satellite;

calculating the common TA based on the feeder link delay, the service link delay, the feeder link delay drift rate, and the reference time; and

calculating a transmit time for transmitting an uplink signal according to the close loop TA, the UE specific TA, and the common TA.

Assignments (1)

Continuity (2)

References Cited (11)