Abstract: A beam control subsystem (200, FIG. 2) provides acquisition, synchronization, and traffic beams (142, FIG. 1) to communication devices (130) within a footprint (144) of a system node (110), where each beam comprises a set of beamlets (140). The subsystem (200, FIG. 2) first acquires (302, FIG. 3) and synchronizes (304, FIG. 3 and FIG. 6) with each communication device. Acquisition involves selecting (402, 416, FIG. 4) and combining (404) sets of beamlets (506, 510, FIG. 5), and determining whether any devices within the sets are attempting to acquire the system. If so, synchronization is performed by varying (604, FIG. 6) beamlet weighting coefficients to find, based on modem feedback, a combination of coefficients that yields a maximum signal-to-interference+noise ratio for multiple users within a beam. The communication device is then handed off (612, 614) to a traffic beam. The subsystem (200) continues, based on modem feedback, to adapt (802, 804, FIG.

Abstract: A satellite communications system (10) provides for snap to grid variable beam size digital beamforming. The communications system (10) has an antenna configuration (20) for maintaining communications links with satellite networking equipment, and a signal processing system (30) for processing signals resulting from the communications links. The beamforming subsystem (40) forms beams based on the processed signals wherein the beams match predetermined grid information. The beamforming subsystem (40) includes a grid database (50) containing predetermined grid information. A beamforming processor (60) converts the predetermined grid information contained in the grid database (50) antenna coefficients. An antenna management system forms beams based on the antenna coefficients.

Abstract: A method and apparatus are provided for operating a phased-array antenna (14) on a satellite-based communications node (10) in more than one mode by controlling the number of beam-forming elements and by applying appropriate phase-control and/or amplitude-control coefficients to the selected elements. The antenna can be operated as a diffused-beam antenna at a relatively low data rate, enabling the satellite-communications node (10) to communicate with a first terrestrial communications node (22). The antenna can also be operated to generate multiple focused-beam antenna patterns each communicating at a relatively high data rate, enabling the satellite-communications node (10) to communicate with a different terrestrial communications node (20) by changing the amplitude and/or the phase coefficients as well as the number of beam-forming elements.

Abstract: In a satellite communication system, beamforming is performed at baseband frequencies forming only beams which convey information. A received signal is applied to a downconverter (FIG. 1, 30), followed by a channelizer (50), and digital beamformer (60). The order of operations being reversed in order to generate a transmit beam. By performing the beamforming at baseband, the system can be allowed to form only those beams which convey information between a communications node and a subscriber. As a result, the system provides communication services to subscribers in a more cost-effective manner.

Abstract: The invention describes a method and system for the calibration of sectionally assembled phased array antennas. When a large, multi-sectioned phased array antenna on board a satellite (10, FIG. 1) is unfolded during deployment, an error in the alignment of a phased array antenna section (25) can cause an error in the pointing angle of the transmit antenna beam (50). A suitable receive antenna (80) receives a signal from the transmit antenna beam (50) which enables a processor unit (95, FIG. 2) to determine the required correction factor. The correction factor is then applied to the beam coefficients which control the beam of the phased array antenna section (25). Subsequent to a first measurment, the correction factor can be updated to minimize the impact of antenna element failures on the resulting antenna pattern.