Timing half-duplex transmissions

1 . A method comprising:

determining, at a satellite in communication with a plurality of half-duplex user terminals, a maximum round-trip propagation delay associated with one or more half-duplex user terminals of the plurality of half-duplex user terminals, wherein each half-duplex user terminal of the plurality of half-duplex user terminals is associated with a propagation delay less than or equal to the maximum round-trip propagation delay;

determining, based on the maximum round-trip propagation delay and one or more additional delays, a respective downlink to uplink (DL/UL) offset for each half-duplex user terminal of the plurality of half-duplex user terminals, wherein the DL/UL offset comprises a time difference between a first downlink frame at the satellite and a first corresponding uplink frame at the satellite;

transmitting, from the satellite, a first downlink frame to the plurality of half-duplex user terminals, wherein the first downlink frame comprises the DL/UL offset;

receiving, at the satellite, a first uplink frame from a first half-duplex user terminal of the plurality of half-duplex user terminals during the first corresponding uplink frame at the satellite, wherein a first propagation delay associated with the first half-duplex user terminal comprises the maximum round-trip propagation delay; and

receiving, at the satellite, a second uplink frame from a second half-duplex user terminal of the plurality of half-duplex user terminals during the first corresponding uplink frame at the satellite, wherein a second propagation delay associated with the second half-duplex user terminal is shorter than the maximum round-trip propagation delay.

2 . The method of claim 1 , wherein the plurality of half-duplex user terminals is grouped in a plurality of half-duplex user terminal groups.

3 . The method of claim 2 , wherein a duration of the DL/UL offset is greater than a duration of N number of downlink frames at the satellite, where Nis an integer, and wherein a number of groups included in the plurality of half-duplex user terminal groups is less than N.

4 . The method of claim 2 , wherein the first half-duplex user terminal of the plurality of half-duplex user terminals associated with the maximum round-trip propagation delay is included in a first group of the plurality of half-duplex user terminal groups associated with the first downlink frame and the second half-duplex user terminal is included in a second group of the plurality of half-duplex user terminal groups associated with the first downlink frame.

5 . The method of claim 1 , further comprising:

determining, at a different location of the satellite, a second DL/UL offset for a first group of the plurality of half-duplex user terminals, wherein the first group of the plurality of half-duplex user terminals comprises the first half-duplex user terminal of the plurality of half-duplex user terminals associated with the maximum round-trip propagation delay, and wherein the second DL/UL offset is less than the DL/UL offset; and

determining a transmit offset delay for transmitting a third downlink frame to the first group of the plurality of half-duplex user terminals, wherein the transmit offset delay comprises a difference between the second DL/UL offset and the DL/UL offset.

6 . The method of claim 1 , wherein the one or more additional delays comprises at least one or more of a user terminal processing delay, a user terminal transmit (Tx) mode to receive (Rx) mode transition delay, or a user terminal Rx mode to Tx mode transition delay.

7 . The method of claim 1 , wherein the second half-duplex user terminal begins transmission of the second uplink frame after the first half-duplex user terminal begins transmission of the first uplink frame.

8 . The method of claim 1 , wherein a beginning time of the first uplink frame is misaligned in time with a beginning time of a concurrent downlink frame at the satellite.

9 . At least one non-transitory computer-readable storage medium comprising instructions stored thereon which, when executed by one or more processors, cause the one or more processors to:

determine, at a satellite in communication with a plurality of half-duplex user terminals, a maximum round-trip propagation delay associated with one or more half-duplex user terminals of the plurality of half-duplex user terminals, wherein each half-duplex user terminal of the plurality of half-duplex user terminals is associated with a propagation delay less than or equal to the maximum round-trip propagation delay;

determine, based on the maximum round-trip propagation delay and one or more additional delays, a respective DL/UL offset for each half-duplex user terminal of the plurality of half-duplex user terminals, wherein the DL/UL offset comprises a time difference between a first downlink frame at the satellite and a first corresponding uplink frame at the satellite;

transmit, from the satellite, a first downlink frame to the plurality of half-duplex user terminals, wherein the first downlink frame comprises the DL/UL offset;

receive, at the satellite, a first uplink frame from a first half-duplex user terminal of the plurality of half-duplex user terminals during the first corresponding uplink frame at the satellite, wherein a first propagation delay associated with the first half-duplex user terminal comprises the maximum round-trip propagation delay; and

receive, at the satellite, a second uplink frame from a second half-duplex user terminal of the plurality of half-duplex user terminals during the first corresponding uplink frame at the satellite, wherein a second propagation delay associated with the second half-duplex user terminal is shorter than the maximum round-trip propagation delay.

10 . The at least one non-transitory computer-readable storage medium of claim 9 , wherein the plurality of half-duplex user terminals is grouped in a plurality of half-duplex user terminal groups.

11 . The at least one non-transitory computer-readable storage medium of claim 10 , wherein the first half-duplex user terminal of the plurality of half-duplex user terminals associated with the maximum round-trip propagation delay is included in a first group of the plurality of half-duplex user terminal groups associated with the first downlink frame and the second half-duplex user terminal is included in a second group of the plurality of half-duplex user terminal groups associated with the first downlink frame.

12 . The at least one non-transitory computer-readable storage medium of claim 9 , further comprising instructions stored thereon which, when executed by one or more processors, cause the one or more processors to:

determine, at a different location of the satellite, a second DL/UL offset for a first group of the plurality of half-duplex user terminals, wherein the first group of the plurality of half-duplex user terminals comprises the first half-duplex user terminal of the plurality of half-duplex user terminals associated with the maximum round-trip propagation delay, and wherein the second DL/UL offset is less than the DL/UL offset; and

determine a transmit offset delay for transmitting a third downlink frame to the first group of the plurality of half-duplex user terminals, wherein the transmit offset delay comprises a difference between the second DL/UL offset and the DL/UL offset.

13 . The at least one non-transitory computer-readable storage medium of claim 9 , wherein the one or more additional delays comprises at least one or more of a user terminal processing delay, a user terminal Tx mode to Rx mode transition delay, or a user terminal Rx mode to Tx mode transition delay.

14 . The at least one non-transitory computer-readable storage medium of claim 9 , wherein a beginning time of the first uplink frame is misaligned in time with a beginning time of a concurrent downlink frame at the satellite.

15 . A system comprising:

at least one memory; and

at least one processor coupled to the at least one memory and configured to:

determine, at a satellite in communication with a plurality of half-duplex user terminals, a maximum round-trip propagation delay associated with one or more half-duplex user terminals of the plurality of half-duplex user terminals, wherein each half-duplex user terminal of the plurality of half-duplex user terminals is associated with a propagation delay less than or equal to the maximum round-trip propagation delay;

determine, based on the maximum round-trip propagation delay and one or more additional delays, a respective DL/UL offset for each half-duplex user terminal of the plurality of half-duplex user terminals, wherein the DL/UL offset comprises a time difference between a first downlink frame at the satellite and a first corresponding uplink frame at the satellite;

transmit, from the satellite, a first downlink frame to the plurality of half-duplex user terminals, wherein the first downlink frame comprises the DL/UL offset;

receive, at the satellite, a first uplink frame from a first half-duplex user terminal of the plurality of half-duplex user terminals during the first corresponding uplink frame at the satellite, wherein a first propagation delay associated with the first half-duplex user terminal comprises the maximum round-trip propagation delay; and

receive, at the satellite, a second uplink frame from a second half-duplex user terminal of the plurality of half-duplex user terminals during the first corresponding uplink frame at the satellite, wherein a second propagation delay associated with the second half-duplex user terminal is shorter than the maximum round-trip propagation delay.

16 . The system of claim 15 , wherein the plurality of half-duplex user terminals is grouped in a plurality of half-duplex user terminal groups.

17 . The system of claim 16 , wherein the first half-duplex user terminal of the plurality of half-duplex user terminals associated with the maximum round-trip propagation delay is included in a first group of the plurality of half-duplex user terminal groups associated with the first downlink frame and the second half-duplex user terminal is included in a second group of the plurality of half-duplex user terminal groups associated with the first downlink frame.

18 . The system of claim 15 , wherein the at least one processor is configured to:

determine, at a different location of the satellite, a second DL/UL offset for a first group of the plurality of half-duplex user terminals, wherein the first group of the plurality of half-duplex user terminals comprises the first half-duplex user terminal of the plurality of half-duplex user terminals associated with the maximum round-trip propagation delay, and wherein the second DL/UL offset is less than the DL/UL offset; and

determine a transmit offset delay for transmitting a third downlink frame to the first group of the plurality of half-duplex user terminals, wherein the transmit offset delay comprises a difference between the second DL/UL offset and the DL/UL offset.

19 . The system of claim 15 , wherein the one or more additional delays comprises at least one or more of a user terminal processing delay, a user terminal Tx mode to Rx mode transition delay, or a user terminal Rx mode to Tx mode transition delay.

20 . The system of claim 15 , wherein a beginning time of the first uplink frame is misaligned in time with a beginning time of a concurrent downlink frame at the satellite.