# US 2021/0345398 A1 · Adaptive random access response window > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0345398 A1 - Document ID: US20210345398A1 - Status: Published application - Kind: A1 - Application number: 17/377,928 - Filed: 2021-07-16 - Published: 2021-11-04 - Earliest claimed: 2019-01-17 - Assignees: Zte Corporation - Applicants: Zte Corporation - Inventors: Wei CAO; Zhen YANG; Nan ZHANG; Jianwu DOU; Linxi HU - Web page: https://patentgrep.com/patent/US20210345398A1 ## CPC - H04W 74/002: {Transmission of channel access control information} - H04B 7/1851: {Systems using a satellite or space-based relay (H04B7/18508, H04B7/18521 take precedence; providing specific services H04B7/18523 - H04B7/18576)} - H04W 56/00: Synchronisation arrangements - H04W 56/0045: {compensating for timing error by altering transmission time} - H04W 56/0055: {determining timing error of reception due to propagation delay} - H04W 74/006: {in the downlink, i.e. towards the terminal} - H04W 74/0833: Random access procedures, e.g. with 4-step access - H04W 48/12: using downlink control channel - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04B: TRANSMISSION ## Abstract 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. ## Claims ### Claim 1 A method performed by a communication device, comprising: determining a start of a random access response window and monitoring for a signal from a communication node within the random access response window, wherein the communication node communicates using a satellite in orbit or a high altitude platform station (HAPS). ### Claim 2 (depends on 1) The method of claim 1, further comprising: determining a propagation delay, based on 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. ### Claim 3 (depends on 2) The method of claim 2, further comprising: determining a minimum propagation delay, delay_min, for communications between the communication device and the communication node, based on the system information; determining a maximum propagation delay, delay_max, 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. ### Claim 4 (depends on 1) 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. ### Claim 5 (depends on 1) The method of claim 1, further comprising: determining a start of a random access response window, wherein the adaptive 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 wherein the adaptive random access response window starts from T1+delay_calc*2, where T1 is the a Message 1 transmission finish time of the communication device, if the communication device has access to situation information. ### Claim 6 (depends on 1) 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. ### Claim 7 (depends on 2) The method of claim 2, wherein the maximum propagation delay and the minimum propagation delay is determined using a look up table based on system information and/or the situation information comprising: an altitude of the satellite or the HAPS; a minimum elevation angle of a serving beam; a maximum elevation angle of a serving beam; and a payload type of the satellite or the HAPS. ### Claim 8 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. ### Claim 9 (depends on 8) The method of claim 8, 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. ### Claim 10 (depends on 9) The method of claim 9, 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. ### Claim 11 (depends on 10) The method of claim 10, wherein the first period and the second period are of different durations. ### Claim 12 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11) A non-transitory computer-readable medium having stored thereon computer-executable instructions for carrying out any one of the methods of claims 1 through 11. ### Claim 13 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. ### Claim 14 (depends on 13) The communication device of claim 13, 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. ### Claim 15 (depends on 13) The communication device of claim 13, wherein the adaptive random access response window: starts from T1+delay_min*2, where T1 is the 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 the a Message 1 transmission finish time of the communication device, if the communication device has access to situation information. ### Claim 16 (depends on 13) The communication device of claim 13, 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. ### Claim 17 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. ### Claim 18 (depends on 17) The communication node of claim 17, 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. ### Claim 19 (depends on 18) The communication node of claim 18, 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. ### Claim 20 (depends on 19) The communication node of claim 19, wherein the first period and the second period are of different durations.