A satellite constellation provides communication between user terminals (UTs) and ground stations that connect to other networks, such as the Internet. Satellites transmit beacon transmissions to particular areas on Earth as particular times. The beacon transmissions include information used by a UT to use a random access channel (RACH) uplink to request communication. Responsive to the request, encryption is established between the satellite and the UT. The satellite may then allocate uplink resources, send data to the UT on a downlink, and so forth. The UT receives additional data about future handovers to other satellites. Based on previously received data the UT may quickly re-establish communication with a satellite after an interruption, such as due to a power outage at the UT. If the previously received data has expired, the UT may again use a beacon transmission.

Described herein are systems, methods, and other techniques for handling timing in a satellite communication system having a gateway and a terminal. PDUs to be transmitted are received at the gateway. A traffic adapter computes a release time at which a baseband frame containing the PDUs is to be released. The traffic adapter generates the baseband frame containing the PDUs and a timing packet including a reference time. The traffic adapter tags the release time to the baseband frame. A virtual transmitter modulates the baseband frame, generates a digital IF packet containing the modulated baseband frame, and inserts the release time into a header of the digital IF packet. A digitizer releases the modulated baseband frame at the release time for transmission to the terminal via a satellite.

A method includes receiving a first antenna stream from a first feeder link to a first non-terrestrial network payload, wherein the first antenna stream includes signals transmitted by terminal devices that are synchronized in time, receiving a second antenna stream from a second feeder link to a second non-terrestrial network payload, wherein the second antenna stream includes signals transmitted by the terminal devices that are not synchronized in time, storing the first and second antenna streams in buffers, obtaining a first timing advance, obtaining a second timing advance, obtaining an estimation of timing offset based on the timing advances, obtaining the second antenna stream from a second one of the buffers and performing timing offset compensation to the second antenna stream based on the estimation of the timing offset, and obtaining the first antenna stream from a first one of the buffers synchronized with the second antenna stream.

Apparatus and method for communication in non-terrestrial networks are provided. Downlink transmissions are received (400) from one or more non-terrestrial nodes. Signal strengths and/or signal quality of the transmissions are measured (402) from the one or more non-terrestrial nodes. Transitions between line-of-sight and non-line-of-sight states regarding the one or more non-terrestrial nodes are determined (404). Locations of the one or more non-terrestrial nodes and the apparatus are determined (406) and elevation and azimuth angles to the one or more non-terrestrial nodes from the apparatus are calculated (408). A database of the line-of-sight and non-line-of-sight states is generated (410) as a function of elevation and azimuth angles and apparatus location and utilised (412) to determine expected line-of-sight and non-line-of-sight states for non-terrestrial nodes.

A method is provided for compensating time differences for the time alignment of uplink service frames and downlink service frames, the uplink service frames and the downlink service frames being exchanged between a satellite and a mobile terminal. The mobile terminal belonging to a 5G cell comprising a cell centre, the pre-compensation is calculated on the basis of a main beam directed towards the centre (O) of the cell (5G).

Apparatuses, methods, and systems for managing a connection of a wireless device to a satellite network are disclosed. One method includes maintaining, by a core network of the satellite network, a parameter list that includes at least an estimate of a location of the wireless device and an estimate of one or more satellite locations, estimating, by the core network, a probability of a mapping of a wireless connection between the wireless device and a base station supporting the satellite network based upon the parameter list, and initiating, by the core network, a procedure to communicate with the wireless device through the base station based on the estimated probability of the mapping of the wireless connection between the wireless device and the base station.

The present disclosure relates, in part, to non-terrestrial communication systems, and in some embodiments to the integration of terrestrial and non-terrestrial communication systems. Non-terrestrial communication systems can provide a more flexible communication system with extended wireless coverage range and enhanced service quality compared to conventional communication systems. A method representative of aspects of the present application includes receiving, by an apparatus connected in a first type of sub-system, signaling to notify the apparatus to turn-on a connection to a second type of sub-system. The method further includes communicating, upon turning on the connection to the second type of sub-system, using the connection to the second type of sub-system, according to a configuration parameter associated with the type of the second type of sub-system.

Embodiments of this application provide a satellite call method and a terminal device. The method includes: making a satellite call and displaying a call interface based on communication with a first satellite; determining an azimuth angle deviation and a pitch angle deviation, and the satellite transmission link direction is a direction from a position of the terminal device to a position of the first satellite; and displaying prompt information on the call interface if the azimuth angle deviation and the pitch angle deviation satisfy a preset condition, where the prompt information prompts a user that there is a possibility that a call on the terminal device is interrupted. The method helps the user to adjust the position of the terminal device in a timely manner, to avoid call interruption, and improve user experience.

The technology employs a polarization switching technique in a satellite-based cellular communication system, in order to prevent dropped connections when communicating with client communication devices. The polarization switching is implementable without requiring additional antenna elements on the satellite(s), while enabling the satellites(s) to be agnostic to the polarization transmitted by user equipment. The dwell time is selected so that the polarization switching is transparent to the users of the client computing devices. In one configuration, certain antenna elements can be set to handle a vertically polarized downlink and a horizontally polarized uplink, while other elements are set to handle a vertically polarized uplink and a horizontally polarized downlink, although other polarization configurations may be employed. A digital switch with a general purpose I/O (GPIO) controller may be employed for switching according to the dwell time.

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may be configured to buffer communications with a network node. A buffer size of a buffer used to buffer the communications may be specific to a non-terrestrial network (NTN) via which the UE communicates with the network node. For example, the UE may calculate the buffer size based on a maximum data rate of a connection with the network node via the NTN and a radio link control (RLC) round trip time (RTT). The RLC RTT may be specific to NTNs. The UE may use a buffer having the calculated buffer size to buffer the communications between the UE and the network node over the connection.