Ford Motor Company Limited

Globalstar, Inc.

Lockheed Martin Corporation

Loral Aerospace Corp.

Richard H Sherman

Melvin G Gable

Theodore F Driggers

Vijaya Korwar Gallagher

Stephen P Boyd

Fumin Yuan

Billy D Pettijohn

Delmer R Schneider, Jr

John J Huang

George W Dinolt

Chamroenu Kchao

Frank Hubbard

Vadivelu Jeyabalan

Systems and methods for protecting privacy in transmitting an analog information signal. The present invention combines the information signal with an analog random signal generated by a chaotic circuit and transmits the signal. The received signal is synchronized using a receiving chaotic circuit. The received signal is demodulated using a synchronized replica of the analog random signal. The information signal is recovered since the product of the random signals generated in the transmitter and in the receiver, is unity. Techniques used in the present invention for generating chaos, synchronization, and signal recovery are also disclosed.

Chaotic privacy system and method

A method and apparatus (system) for providing forward-link channel-frequency allocation for multiple-satellite cellular communications networks is disclosed. The system has a centralized ground-operations control center that provides bi-weekly minute-by-minute allocation plans for geographically-defined service areas. This enables each service area to set its diversity policy in accordance with the requirements of the government regulators and customer preferences within the service area. The system has a user model having a frequency re-use pattern, a channel allocation model for modelling the power allocated to each channel, and a gateway channel model for allocating channels in accordance with the user model and the channel allocation model. The allocation is made for each satellite of the plurality of satellites. The traffic allocation induces an operating frequency for each of the one or more links in each satellite of the plurality of satellites. The satellite communication system computed frequency allocation is optimized to minimize total radiation from all forward links for one or more of the plurality of satellites.

Channel frequency allocation for multiple-satellite communication network

A satellite communications system is described. The system includes a plurality of satellites, each of which transmits one or more forward links containing traffic to one or more terrestrial users. Each forward link of each of the satellites has a maximum radiation limit. At least one terrestrial user is capable of concurrently receiving at least two of the forward links. The concurrently received forward links redundantly contain the traffic addressed to the user. A computing center has a traffic controller for allocating the traffic to the satellites using gateways. The traffic controller includes a fading model descriptive of fading characteristics for each of the one or more forward links; a link performance model descriptive of losses in each of the forward links; and a power allocation model for computing a traffic allocation for each satellite of the constellation of satellites. The traffic allocation causes transmitted satellite power to be less than the maximum radiation limit for each link. The traffic control system may be located within a gateway so as to optimize traffic associated with that gateway alone. The optimization may also be directed to minimize total radiation from all forward links for particular satellites.

Multiple satellite system power allocation by communication link

A satellite communications system operative with at least one existing terrestrial communication system for carrying traffic is described. The communication system has a plurality of satellites in earth orbits, each satellite including a battery for sourcing electrical energy. The battery has energy sourcing limits. Gateways, bidirectionally linked to the plurality of satellites are also provided. A computing center, linked to the gateways, has a traffic control means for allocating traffic to the gateways. The traffic control means has three parts a power demand model for computing a first traffic allocation of traffic for each satellite; a satellite battery performance model descriptive of the energy sourcing limits of the on-board batteries; and a control law for applying weights to the first traffic allocation by using the battery performance model to obtain a second traffic allocation for each satellite. The second traffic allocation induces an electrical energy consumption in each of the satellites that is less than the battery energy sourcing limits.

Dynamic traffic allocation for power control in multiple satellite

A computer workstation having a window output display for potential use in security-sensitive environments provides multilevel security by physical isolation of processes in predefined security levels, each process or like-classified group of processes is displayed only through a suitably labeled window, access to the window requiring access through a previously security qualified physical signal path. The invention does not compromise security by mixing a software-based security environment with other untested software. All security is hardware-based.

Multilevel secure workstation

A data communication system for providing data transmission between a plurality of individually addressable local computer networks, by utilizing single node switching across a common passive bus medium. The passive bus medium is characterized as having a plurality of separate conductors of limited length that are each commonly connected to individual bus interface circuits for each local computer network. Each bus interface circuit has a number of dedicated address data ports, message data ports and control ports that are connected to separate dedicated conductors of the passive bus medium for transmitting data to and receiving data from other local computer networks. Each message transmission of data on the passive bus medium is divided into a number of mini-packets each of which contain a number of parallely transmitted bits corresponding to the number of dedicated address and message conductors in the passive bus medium. Each mini-packet is separately transmitted on the passive bus medium and separately acknowledged by the designated receiving bus interface circuit. Mini-packets are of two types for each message. The first group of mini-packets precedes the second group and contains destination address in its header portion and word count information in its message portion. The second group constitutes the remainder of the message and each mini-packet of this group contains the source address in the header portion and message data in the message portion.

Data communication system

A coaxial cable coupler that provides a low impedance through conductor for a passive coaxial transmission cable and a high impedance tap to periodic transmission means and receiver means. The tap connection is a removable connection that is formed by a resilient electrical conductor compressed between exposed portions of the main transmission through conductor and an exposed tap conductor interconnecting the high impedance networks of the transmission means and the receiver means.

Coaxial cable tap coupler for a data transceiver

A plurality of transceivers frequently share a common communication medium or radio frequency channel. A broadcast channel can support only a limited number of transceivers. At some point, the shared channel will become so busy that additional transceivers will divide up more of an already inadequate bandwidth. To reduce the traffic, a broadcast channel is split into separate segments. A segment interface apparatus is used to couple two broadcast segments together. A hierarchical address is employed in the header of each packet transmitted on the medium. The segment interface apparatus compares fields in the header with that of internal registers to determine if the packet should be repeated on the other broadcast segment. An access level within the packet is decremented by the segment interface to control the number of times a packet is repeated.

Interface between communication channel segments

The Local Network Architecture (LNA) is an organization of a data communication network where the control and access to the communication channel is handled local to each user device interface. The device interface (Local Netowrk Architecture Interface or LNAI) is an electronic module which interfaces a user with the LNA communication network. This device adapter contains both a network port and a user interface port. This interface accepts user data and fragments it into data packets for shipment over a shared communication medium which is connected to the network port. A communication microprocessor is used to implement the functions of data buffering, routing, sequencing, flow control, acknowledging and error checking of data. Such distributed control eliminates the need for messages in the network to be forwarded to a message flow control process or computer station. Users supported by the system can include microprocessor based systems, programmable controllers, terminal devices, minicomputers and larger host computers. Since users differ in their exact communication conventions certain 'personalities' can be imparted to the LNA device interface. These personalities allow data to be transmitted between users in a full transparent information mode in such a fashion as to be compatible with protocols implemented by those users and at different user transmission rates.

Communication broadcast channel interface

An encoder of a transmitter converts digital data or analog signal information into an encoded sequence or waveform required by a communication channel. If a plurality of transmitters are to share a common channel or medium, then the correlation properties of the encoded signal are important. The encoding apparatus should employ a code which is not very susceptible to noise, yet will permit the detection of multiple transmissions of similar spectrum signals. The apparatus disclosed in this specification is concerned with a binary digital information encoder whose input is either a 'zero' or 'one' state. The encoder generates a ternary code sequence for encoding one binary input state with the sequence + 1,+1,0,0,-1,-1 and the other binary input state with the sequence represented by +1,0,+1,-1,0,-1.

Data communication code

An apparatus for enabling communications between two or more transceivers when a plurality of transceivers share a common communication medium or channel. The geographical locations of the transceivers are such that the propagation delay between any source to destination pair is relatively a small function of the transmission duration or packet time. In order to prevent two or more transceivers from simultaneously transmitting over the common medium, each transceiver requires a control apparatus. The simultaneous transmission by two or more transceivers is not very likely due to different start times. However, if such start times differ by less than the propagation delay between the transceivers then interference will result. Hence the control apparatus includes a means of resolving such contention interferences by providing a retransmission delay to govern the transmission.

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Fremont, CA, United States of America

Richard H Sherman