Methods, systems, and devices for wireless communications are described in which random access preambles may be designed to provide for relatively low inter-carrier interference (ICI) of adjacent available frequency resources in a non-terrestrial network (NTN). Random access preambles for NTN random access requests may be selected from a first set of random access preambles that are different from a second set of random access preambles for terrestrial random access requests. The first set of random access preambles may be a subset of the second set of random access preambles. The first set of random access preambles may be provided for contention-based random access (CBRA) and contention-free random access (CFRA) preambles may be configured by a base station from random access preambles that correspond to or are different from the second set of random access preambles.

A network for providing high speed data communications may include multiple terrestrial transmission stations that are located within overlapping communications range and a mobile receiver station. The terrestrial transmission stations provide a continuous and uninterrupted high speed data communications link with the mobile receiver station employing a wireless radio access network protocol.

A satellite communication earth station includes a detection unit that detects a longitude, a latitude, an altitude, an azimuth, and an inclination of the antenna, a drive unit that drives the antenna to adjust the azimuth angle, the elevation angle, and the polarization angle of the antenna to the communication satellite, a determination unit that determines whether the longitude, the latitude, the altitude, the azimuth, or the inclination detected by the detection unit or the azimuth angle, the elevation angle, or the polarization angle driven by the drive unit makes a change from an initial setting value to a predetermined threshold value or more, and a minimum control calculation unit that calculates control to minimize a drive amount driven by the drive unit to adjust the current azimuth angle, the elevation angle, and the polarization angle of the antenna to the communication satellite.

In one embodiment, an antenna system is described. The antenna system includes a primary antenna on an aircraft. The primary antenna is mechanically steerable and has an asymmetric antenna beam pattern with a narrow beamwidth axis and a wide beamwidth axis at boresight. The antenna system also includes a secondary antenna on the aircraft, the secondary antenna including an array of antenna elements. The antenna system also includes an antenna selection system to control communication of a signal between the aircraft and a target satellite via the primary antenna and the secondary antenna. The antenna selection system switches communication of the signal from the primary antenna to the secondary antenna when an amount of interference with an adjacent satellite reaches a threshold due to the wide beamwidth axis of the asymmetric antenna beam pattern.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may transmit a physical uplink shared channel (PUSCH) message associated with a random access channel (RACH) procedure to a non-terrestrial network node. The UE may monitor a physical downlink control channel (PDCCH) for a contention resolution message associated with the RACH procedure during a contention resolution window. In some aspects, the UE may start to monitor the PDCCH a variable time period after the PUSCH message is transmitted. Numerous other aspects are provided.

Systems and methods are disclosed herein for supporting coherent transmissions in a wireless network such as a Non-Terrestrial Network (NTN). In one embodiment, a method performed by a wireless communication device comprises starting an uplink transmission and performing one or more actions comprising creating a time gap within the uplink transmission and/or muting a portion of the uplink transmission to support a timing advance of the continued uplink transmission. The method further comprises performing time-frequency compensation during a time period created by performing the one or more actions and continuing the uplink transmission after performing the time-frequency compensation. In this manner, a low-complexity method for achieving a compensation for a time variant Doppler shift is provided. This offers a predictability that can be used in a wireless network such as, for example, an NTN for supporting coherent demodulation and optimized receiver implementations.

A method for a user equipment (UE) operating in a non-terrestrial network (NTN) is provided. The method includes receiving, from a base station (BS), assistance information; starting or restarting a timer upon receiving the assistance information; applying the assistance information to perform uplink synchronization; and determining that the UE has lost the uplink synchronization upon expiration of the timer.

A Non-Geostationary Satellite Orbit (NGSO) satellite system is described that implements one or more user route tables and a plurality of pre-calculated backbone route tables at its satellites. The user route tables track user connectivity to the satellites, and each of the backbone route tables defines a snapshot of a time-varying backbone topology seen by a particular satellite. During operation, a satellite selects different backbone route tables as the topology changes over time, and receives updates to the user route tables when connectivity changes occur between the users and the satellites. The decoupling of the user route tables from the backbone route tables at the satellite reduces the computational burden on the NGSO system, as the backbone route tables are calculated in advance and the NGSO system is subsequently tasked with a computationally lower burden of performing real-time updates to the user route tables.

Methods, systems, and devices for wireless communications are described. A user equipment (UE) and a satellite of a non-terrestrial network (NTN) may establish communications on a beam of the satellite. The UE may receive, on a first carrier of a first set of carriers associated with a first beam, a configuration for the first set of carriers associated with the first beam and a second set of carriers associated with a second beam. The first carrier may be used to send a first set of synchronization signals, and a second carrier of the second set of carriers may be used to send a second set of synchronization signals. The UE may identify some system information associated with the second set of carriers based on the configuration and reselect to the second beam based on the configuration.

Aspects relate to delay management techniques to handle delays introduced by high latency links in non-terrestrial networks for non-access stratum (NAS) mobility management and session management procedures. The NAS timers within the user equipment (UE) and core network utilized for mobility management and session management procedures may be configured with different durations, such as a normal duration, an extended duration, or a reduced duration, based on whether the UE is connected to a terrestrial or non-terrestrial radio access network (RAN), one or more capabilities of the UE, and/or the various RAN types (e.g., terrestrial or non-terrestrial) within a registration area that the UE is located in.