Synchronizing wireless communications between user equipment and non-terrestrial networks

A user equipment (UE) base station comprising one or more processors configured to perform operations comprising:

• determining a trajectory and an elevation angle of a first communications satellite of a non-terrestrial network relative to a user equipment (UE);
• determining, based on the trajectory and the elevation angle of the first communication satellite, whether one or more first criteria have been satisfied;
• and
• performing at least one of:
• upon determining that the one or more first criteria have been satisfied, causing the UE to perform a 2-Step Random Access Channel (RACH) procedure with respect to the first communications satellite and the non-terrestrial network, or
• upon determining that the one or more first criteria have not been satisfied, causing the UE to perform a 4-Step RACH procedure with respect to the first communications satellite and the non-terrestrial network.

An apparatus comprising one or more baseband processors configured to perform operations comprising:

• determining a trajectory and an elevation angle of a first communications satellite of a non-terrestrial network relative to a user equipment (UE);
• determining, based on the trajectory and the elevation angle of the first communication satellite, whether one or more first criteria have been satisfied;
• and
• performing at least one of:
• upon determining that the one or more first criteria have been satisfied, causing the UE to perform a 2-Step Random Access Channel (RACH) procedure with respect to the first communications satellite and the non-terrestrial network, or
• upon determining that the one or more first criteria have not been satisfied, causing the UE to perform a 4-Step RACH procedure with respect to the first communications satellite and the non-terrestrial network.