Viasat, Inc.

Donald C Wilcoxson

Brian T Sleight

John Hai O'Neill

Daniel Chester

Changping Li

Shay Har-Noy

Edward A Smith

Techniques for improving data rates at mobile terminals that are subject to periodic channel interruptions in a beyond-line-of-sight communication system are disclosed, including improved encoding and decoding systems that identify blockages and modify receiver operation during blockages to reduce data errors. In certain embodiments, encoding, symbol mapping, interleaving, and use of unique periodic identifiers function to enable a series of packets that may be received in a blockage impaired channel with reduced errors.

Cyclical obstruction communication system

Network communications face security issues including traffic flow analysis attacks. Such attacks include deduction of information about networks through analysis of transmitted traffic volume or statistics, even if the traffic is encrypted. For example, an adversary may deduce operational information from traffic volume, or its timing. Described herein are security techniques that can provide transmission security with an obfuscating 'cover' signal for any contention-based multiple access system by employing signal interference cancellation techniques, but are not so limited. The cover signal is transmitted on the same frequency band used by terminals on the network. Using 'known-signal' and/or self-interference cancellation techniques, the cover signal can be removed by authorized terminals that have appropriate cover signal information and timing synchronization. An adversary cannot distinguish between real traffic and the cover signal while authorized terminals can recover transmissions without impact to network capacity.

Traffic flow analysis mitigation using a cover signal

Techniques for enabling broadband data rates at mobile terminals in a beyond-line-of-sight communication system are disclosed. Forward link time-diversity transmission methods and a time-diversity transmitter based upon blockage characteristics are provided. The transmitter optionally supports selective time-diversity and can operate at Ku-band or higher frequencies. A forward link time-diversity receiver and methods for receiving a forward link time-diversity signal are also disclosed. The forward link time-diversity receiver optionally provides low-jitter or low-delay characteristics. A return link transmitter and return link transmit methods which avoid blockages are also disclosed. The return link transmitter can include a signal presence detector and blockage prediction filter.

Methods and systems are provided for satellite communication wherein a plurality of geographically-separated apertures are controlled by a central controller that analyzes link availability of each aperture and then user connectivity is prioritized above a minimum user data rate, whereupon the gateway-established data rate of lower priority users is reduced to allocate more capacity to highest priority users, which are routed through available links in order to better optimize a gateway architecture, to reduce gateway costs and to improve effective performance in the presence of atmospheric interference events.

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Oceanside, CA, United States of America

Donald C Wilcoxson