Methods and systems for calibrating the return and forward links of a satellite communication system are provided according to embodiments of the invention. The phase and/or amplitude variations caused by the return and forward links are calculated and/or estimated to aid in beamforming, such as ground-based beamforming. Calibration earth stations, distributed within one or more beam patterns, may be used to transmit calibration codes to the gateway to calibrate the return link. Return links variations may be estimated using a weighted minimum mean square algorithm at the gateway. Forward links may be calibrated with calibration codes transmitted from the gateway through a hybrid matrix to at least one calibration station. Forward calibration links may also calibrate for temperature-dependent signal variations such as diplexer variations at the satellite.

An improved procedure and associated hardware to allow a satellite to switch antenna coverages according to predefined repetitive sequences and to align switching of the antenna sequence with ground data sequence switching. The principle of synchronisation of the sequence switching is based on the anticipation of the exact time at which change in beam hopping sequence occurs at the satellite, such that a change to a beam hopping sequence can be reflected in ground data sequence switching without losing connectivity between the satellite and ground segment.

An invention to perform a method of cell measurement in a wireless network, wherein the wireless network comprises a plurality of frequency layers, the invention configured to: determine a Measurement Gap Length, MGL, for each one of the plurality of frequency layers operational in the wireless network; determine a gap bitmap to indicate a measurement gap availability in a time sequence for each one of the plurality of frequency layers of the wireless network; and transmit gap assistance information for each one of the plurality of frequency layers of the wireless network to a User Equipment, wherein the gap assistance information comprises at least the determined Measurement Gap Length and the determined gap bitmap.

Methods and systems for calibrating the return and forward links of a satellite communication system are provided according to embodiments of the invention. The phase and/or amplitude variations caused by the return and forward links are calculated and/or estimated to aid in beamforming, such as ground-based beamforming. Calibration earth stations, distributed within one or more beam patterns, may be used to transmit calibration codes to the gateway to calibrate the return link. Return links variations may be estimated using a weighted minimum mean square algorithm at the gateway. Forward links may be calibrated with calibration codes transmitted from the gateway through a hybrid matrix to at least one calibration station. Forward calibration links may also calibrate for temperature-dependent signal variations such as diplexer variations at the satellite.

Methods and apparatus for relay aided beam management in a vehicle communication system are provided. The relay comprises an antenna system including an internal antenna located inside a vehicle and an external antenna located outside the vehicle. The relay further comprises a transceiver operably connected to the antenna system, the transceiver configured to receive, from a base station (BS), a first signal via the external antenna of the antenna system, and receive, from the vehicle, configuration information including at least one of a vehicle speed, or a position of a window of the vehicle or windshield wiper. The relay further comprises a processor operably connected to the antenna system and the transceiver, the processor configured to generate a second signal based on (i) the configuration information and (ii) the first signal, wherein the transceiver is further configured to transmit, to a user equipment (UE), the second signal via the internal antenna.

Methods and apparatus for relay aided beam management in a vehicle communication system are provided. The relay comprises an antenna system including an internal antenna located inside a vehicle and an external antenna located outside the vehicle. The relay further comprises a transceiver operably connected to the antenna system, the transceiver configured to receive, from a base station (BS), a first signal via the external antenna of the antenna system, and receive, from the vehicle, configuration information including at least one of a vehicle speed, or a position of a window of the vehicle or windshield wiper. The relay further comprises a processor operably connected to the antenna system and the transceiver, the processor configured to generate a second signal based on (i) the configuration information and (ii) the first signal, wherein the transceiver is further configured to transmit, to a user equipment (UE), the second signal via the internal antenna.

Disclosed is a communication method of a satellite and a ground station and apparatuses performing the same. The communication method includes transmitting a plurality of frames to a satellite based on a beam hopping time plan (BHTP) of the satellite and a ground station and synchronizing the BHTP based on an index of a frame received through a beam switching window (BSW) allocated to the ground station among the plurality of frames, and an identification value indicating at least one sub-frame included in the frame.

Methods and systems are described for providing end-to-end beamforming. For example, end-to-end beamforming systems include end-to-end relays and ground networks to provide communications to user terminals located in user beam coverage areas. The ground segment can include geographically distributed access nodes and a central processing system. Return uplink signals, transmitted from the user terminals, have multipath induced by a plurality of receive/transmit signal paths in the end to end relay and are relayed to the ground network. The ground network, using beamformers, recovers user data streams transmitted by the user terminals from return downlink signals. The ground network, using beamformers generates forward uplink signals from appropriately weighted combinations of user data streams that, after relay by the end-end-end relay, produce forward downlink signals that combine to form user beams.

Methods and systems are described for providing end-to-end beamforming. For example, end-to-end beamforming systems include end-to-end relays and ground networks to provide communications to user terminals located in user beam coverage areas. The ground segment can include geographically distributed access nodes and a central processing system. Return uplink signals, transmitted from the user terminals, have multipath induced by a plurality of receive/transmit signal paths in the end to end relay and are relayed to the ground network. The ground network, using beamformers, recovers user data streams transmitted by the user terminals from return downlink signals. The ground network, using beamformers generates forward uplink signals from appropriately weighted combinations of user data streams that, after relay by the end-end-end relay, produce forward downlink signals that combine to form user beams.

A system of architecture, apparatus and calibration method is invented for high-power flexible-polarization payload for satellite communications. The system comprises onboard phase-tracked apparatus, flexible polarization mechanism, and in-orbit calibration method. The power combining and polarization performance of the phase-tracked payload is monitored on ground by measuring the cross-polarization discrimination (XPD) and/or axial ratio (AR). The high performance over the life is achieved by optimization of the XPD or AR on ground and adjusting complex gain of the transponders. The high-power flexible-polarization in-orbit-calibration payload may be applied but not limited to UHF, L, S, C, X, Ku and Ka-band high power satellite systems.