Adaptive random access response window
This disclosure relates generally to wireless communications and, more particularly, to systems and methods for determining an adaptive random access response window length in non-terrestrial networks. In one embodiment, a method performed by a communication device includes: receiving system information from a communication node, wherein the communication node communicates using a satellite in orbit or a high altitude platform station (HAPS); and determining an adaptive random access response window length based on the system information and whether the communication device has access to situation information that: characterizes a location of the communication device, an ephemeris of the satellite or a trajectory of the HAPS, and a payload type of the satellite or the HAPS.
1. A method performed by a communication device, comprising:
receiving system information from a communication node, wherein the communication node communicates using a satellite in orbit or a high altitude platform station, HAPS;
determining a start of a random access response window; and
monitoring for a signal from the communication node within the random access response window, wherein the determining the start of the random access response window comprising:
determining a minimum propagation delay, delay min, for communications between the communication device and the communication node, based on the system information; or
determining a propagation delay, delay calc, for communications between the communication device and the communication node, based on the system information and situation information, wherein the random access response window:
starts from T1+delay min*2, where T1 is a Message 1 transmission finish time of the communication device, if the communication device does not have access to situation information; or
starts from T1+delay calc*2, where T1 is a Message 1 transmission finish time of the communication device, if the communication device has access to situation information, wherein the situation information comprises at least one of:
a location of the communication device,
an ephemeris of the satellite, or
a trajectory of the HAPS, or
a payload type of the satellite or the HAPS.
2. The method of claim 1 , wherein the system information comprises:
a maximum propagation delay and a minimum propagation delay; or
two times the maximum propagation delay and two times the minimum propagation delay; or
the minimum propagation delay and a differential between the minimum propagation delay and the maximum propagation delay; or
two times the minimum propagation delay and two times the differential between the minimum propagation delay and the maximum propagation delay.
3. The method of claim 1 , further comprising:
determining a random access response window length to monitor for a signal from the communication node within the random access response window, wherein the random access response window length is two times a differential between the minimum propagation delay and the maximum propagation delay plus a predetermined original random access response window length; or
wherein the random access response window length is a predetermined original random access response window length.
4. The method of claim 1 , wherein the maximum propagation delay and the minimum propagation delay is determined using a look up table based on system information.
5. A method performed by a communication node, comprising:
transmitting system information to a communication device, wherein the communication node communicates using a satellite in orbit or a high altitude platform station (HAPS),
wherein the communication device is configured to determine the start of a random access response window and monitor for a signal from the communication node within the random access response window, wherein the communication device determines the start of the random access response window by performing a process using the system information, the process comprising:
determining a minimum propagation delay, delay min, for communications between the communication device and the communication node, based on the system information; or
determining a propagation delay, delay calc, for communications between the communication device and the communication node, based on the system information and situation information, wherein the random access response window:
starts from T2+delay min*2, where T1 is a Message 1 transmission finish time of the communication device, if the communication device does not have access to situation information; or
starts from T1+delay calc*2, where T1 is a Message 1 transmission finish time of the communication device, if the communication device has access to situation information, wherein the situation information comprises at least one of:
a location of the communication device,
an ephemeris of the satellite, or
a trajectory of the HAPS, or
a payload type of the satellite or the HAPS.
6. The method of claim 5 , wherein the system information comprises at least:
a maximum propagation delay and a minimum propagation delay; or
two times the maximum propagation delay and two times the minimum propagation delay; or
the minimum propagation delay and a differential between the minimum propagation delay and the maximum propagation delay; or
two times the minimum propagation delay and two times the differential between the minimum propagation delay and the maximum propagation delay; or an altitude of the satellite or the HAPS; or
a serving start time; or
a serving duration; or
a minimum elevation angle of a serving beam; or
a maximum elevation angle of a serving beam.
7. The method of claim 6 , wherein the altitude of the satellite or the HAPS, the serving start time, and the serving duration is broadcast with a first period, and the minimum elevation angle of a serving beam and the maximum elevation angle of a serving beam is broadcast with a second period.
8. The method of claim 7 , wherein the first period and the second period are of different durations.
9. A communication device, comprising:
a receiver configured to:
receive system information from a communication node, wherein the communication node communicates using a satellite in orbit or in a high altitude platform station (HAPS); and
a processor configured to:
determine the start of a random access response window and monitor for a signal from the communication node within the random access response window, wherein the processor determines the start of the random access response window by performing a process using the system information, the process comprising:
determining a minimum propagation delay, delay min, for communications between the communication device and the communication node, based on the system information; or
determining a propagation delay, delay calc, for communications between the communication device and the communication node, based on the system information and situation information, wherein the random access response window:
starts from T1+delay min*2, where T1 is a Message 1 transmission finish time of the communication device, if the communication device does not have access to situation information; or
starts from T1+delay calc*2, where T1 is a Message 1 transmission finish time of the communication device, if the communication device has access to situation information, wherein the situation information comprises at least one of:
a location of the communication device,
an ephemeris of the satellite, or
a trajectory of the HAPS, or
a payload type of the satellite or the HAPS.
10. The communication device of claim 9 , wherein the system information comprises at least:
a maximum propagation delay and a minimum propagation delay; or
two times the maximum propagation delay and two times the minimum propagation delay; or
the minimum propagation delay and a differential between the minimum propagation delay and the maximum propagation delay; or
two times the minimum propagation delay and two times the differential between the minimum propagation delay and the maximum propagation delay; or
an altitude of the satellite or the HAPS; or
a serving start time; or
a serving duration; or
a minimum elevation angle of a serving beam; or
a maximum elevation angle of a serving beam.
11. The communication device of claim 9 , wherein the adaptive random access response window length is:
two times a differential between the minimum propagation delay and the maximum propagation delay plus a predetermined original random access response window length; or
a predetermined original random access response window length.
12. A communication node, comprising:
a transmitter configured to:
transmit system information to a communication device, wherein the communication node communicates using a satellite in orbit or a high altitude platform station (HAPS), wherein the communication device is configured to determine the start of a random access response window and monitor for a signal from the communication node within the random access response window, wherein the communication device determine s the start of the random access response window by performing a process using the system information, the process comprising:
determining a minimum propagation delay, delay min, for communications between the communication device and the communication node, based on the system information; or
determining a propagation delay, delay calc, for communications between the communication device and the communication node, based on the system information and situation information, wherein the random access response window:
starts from T1+delay min*2, where T1 is a Message 1 transmission finish time of the communication device, if the communication device does not have access to situation information; or
starts from T1+delay calc*2, where T1 is a Message 1 transmission finish time of the communication device, if the communication device has access to situation information, wherein the situation information comprises at least one of:
a location of the communication device,
an ephemeris of the satellite, or
a trajectory of the HAPS, or
a payload type of the satellite or the HAPS.
13. The communication node of claim 12 , wherein the system information comprises:
a maximum propagation delay and a minimum propagation delay; or two times the maximum propagation delay and two times the minimum propagation delay; or
the minimum propagation delay and a differential between the minimum propagation delay and the maximum propagation delay; or
two times the minimum propagation delay and two times the differential between the minimum propagation delay and the maximum propagation delay; or
an altitude of the satellite or the HAPS; or
a serving start time; or
a serving duration; or
a minimum elevation angle of a serving beam; or
a maximum elevation angle of a serving beam.
14. The communication node of claim 13 , wherein the altitude of the satellite or the HAPS, the serving start time, and the serving duration is broadcast with a first period, and the minimum elevation angle of a serving beam and the maximum elevation angle of a serving beam is broadcast with a second period.
15. The communication node of claim 14 , wherein the first period and the second period are of different durations.