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; and determining the 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. 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 the 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. 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. 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. 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.