Hughes Aircraft Company

Gregory L Mayhew

John G Himes

Mark E Bianco

Marvin D Swensen

James A Kivett

David S Long

Henry E Huey

Apparatus for encoding and decoding the Alternant code family including three parallel special purpose Galois Field processors, and a timing and control unit. The special purpose processors jointly process a time domain algorithm relatively independently of the timing and control unit, and are adapted so that each step of the time domain algorithm is handled by one or more of the processors.

Time domain algebraic encoder/decoder

Communication devices and communication network techniques are employed to meet safety-critical, operational requirements for train location and control in railroad and public transit applications. On-board and trackside communication radios participate in a synchronous, time-slotted communication network, providing contentionless and highly responsive access to all participants. Encrypted, validated, and error protected communication links provide reliable and redundant transfer of information among the train, trackside, and control station radios. Spread spectrum communication techniques enable range measurements between all participants. These wireless communication links relay train range measurements to control or processing stations and relay control information (principally speed commands) from the processing stations to the trains. High resolution position location is determined along elevated, at-grade, and in-tunnel tracks using wireless methods and sparse device placement.

Train location and control using spread spectrum radio communications

A general purpose, high-speed encryption system and method, based on a linear feedback shift register (LFSR) that provides inputs to one or more mathematically independent nonlinear output functions, resulting in the generation of multiple keystream outputs per clock cycle. Due to the parallel architecture, the system need only operate at a rate of 1/N, where N is the number of output functions. For example, the system can encrypt an 8-bit byte in one-eighth the time required for a conventional bit-oriented stream cipher. Alternatively, with high-speed serial-to-parallel and parallel-to-serial interface converters, the system can encrypt a serial data stream at a rate N times that of the system itself.

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Fullerton, CA, United States of America

Gregory L Mayhew