Trw Limited

Northrop Grumman Systems Corporation

Oliver W Saunders

Jean A Develet, Jr

Eldad Perahia

Ronald P Smith

Harvey L Berger

Donald C Wilcoxson

Jaime L Prieto, Jr

Eric R Wiswell

Russell Kadota

An optical communication system has a receiver that includes a plurality of photon counting sensors that each receive photons and generate pulses based on the received photons, and an electronic circuit that aggregates the number of pulses from the plurality of photon counting sensors into a merged pulse count. A demodulator samples the merged pulse count at predetermined time intervals to determine a number of photons received by the plurality of photon counting sensors during different sampling time intervals.

Multiple sensor optical communication systems and methods

One embodiment is a Poisson-based communication system. The system includes a receiver that comprises a photodetector that receives photons and generates pulses based on the received photons, a sampling event counter that counts the number of generated pulses by the photodetector and a demodulator. The demodulator samples the sampling event counter at predetermined time intervals to determine an occurrence of a first state when light pulse energy has been transmitted by a transmitter and received by the photodetector and an occurrence of a second state when light pulse energy has not been transmitted by the transmitter and received by the photodetector.

Poisson-based communication system and methods

A method and system for communicating internet data in a satellite-based communications system. A request for a selected web page is transmitted from either a standard terminal or an enhanced terminal to the satellite. The satellite initially determines whether the transmission came from a standard user or an enhanced terminal. If the request was from a standard terminal, the satellite relays the request for the web page directly to the ground station, which retrieves the requested web page from a local cache or the internet, and transmits the requested web page to the satellite, where the satellite in turn retransmits it to the user terminal. If the original request was transmitted from an enhanced terminal, then the satellite determines whether or not it already has a copy of the requested web page in its on-board memory cache. If the satellite has a copy in its memory cache, the requested web page is retrieved from its memory cache and transmitted to the enhanced terminal. If the satellite does not have a copy of the requested web page, it requests the page from the ground station if the same fashion as with the standard terminal.

Satellite-based communications system having an on-board internet web proxy cache

A communication subsystem ( ) for transmitting error correction coded data in packets ( ) includes an input buffer ( ) storing unencoded data, a product coder ( ) coupled to the input buffer, and a time division transmitter ( ). The product coder ( ) outputs product coded data packets ( ) having a packet size, and the time division transmitter ( ) transmits the product coded data packets ( ) in a data section ( ) of a frame ( ). The data section ( ) has a length substantially equal to an integer multiple of the packet size. The communication subsystem ( ) may use a (s, t)&times;(n, m) product code specifically adapted to product code 53 byte ATM cells. A method for communicating error correction coded data in packets includes storing unencoded data in an input buffer ( ), product coding the unencoded data ( ), and outputting product coded data packets ( ) having a packet size. The method also includes time division transmitting ( ) the coded data packets in a data section ( ) of a frame ( ) where the data section length is substantially equal to an integer multiple of the packet size.

Burst and packet wireless transmission using product codes with iterative decoding

Techniques for trading satellite communication resources include a net work operations controller for receiving an offer and analyzing bids in response to the offer. The network operations controller at least partially revises a downlink schedule of resources in response to the winning bid. A satellite receives information from the network operations controller and configures a switch in the satellite, as well as the downlink schedule, in order to enable data communications through the satellite by the winning bidder.

Communication satellite resource trading techniques

Apparatus for enhancing the processing capabilities of a satellite communication system including an uplink receiver deployable with a first satellite . A first processor deployable on satellite is capable of processing signals from uplink receiver . A link terminal deployable with satellite is capable of receiving signals processed by a second processor from a second intersatellite communication link terminal deployable with a second satellite. A first switch deployable with satellite enables signals from uplink receiver to be utilized by communication link terminal or processor . A downlink transmitter deployable with satellite is capable of transmitting signals to a ground based communication station . A second switch deployable with satellite enables signals from communication link terminal or first processor to be utilized by downlink transmitter

Supplemental satellite communication processing

Apparatus for enhancing the communication capabilities of a satellite communication system including an uplink receiver deployable with a first satellite and capable of receiving signals from a ground-based communication station . A first processor deployable on satellite is capable of processing signals from uplink receiver . A two-way link terminal deployable with satellite is capable of communication with a second two-way intersatellite communication link terminal deployable with a second satellite . A first switch deployable with satellite enables signals from uplink receiver to be utilized by communication link terminal or processor . A downlink transmitter deployable with satellite is capable of transmitting signals to a ground-based communication station . A second switch deployable with satellite enables signals from communication link terminal or first processor to be utilized by downlink transmitter

Supplemental satellite communication enhancement techniques

An antenna system that includes one or more antenna feed horns (,), where each feed horn (,) includes a plurality of micro-mechanical devices (,) positioned around the aperture (,) of the feed horn (,). The micro-mechanical devices (,) are linear motion devices that can be activated to extend a conductive surface (,) beyond the end of the feed horn (,). By selectively actuating groups of the micro-mechanical devices (,) to extend the conductive surfaces (,), the end of the feed horn (,) can be changed to provide different asymmetrical configurations, causing the beam direction to change accordingly. The micro-mechanical devices (,) can be any suitable mechanical device, such as MEMS devices or carbon nanotube artificial muscles.

Steerable offset reflector antenna

The present invention provides a method and apparatus (,) for iteratively decoding data which has been encoded with contatenated codes. The apparatus (,) includes pipelined and cascaded decoder processors (,and,) connected to a multiple block memory device (,), through a multiplexing and data control block (,). A data decision element (,) is provided for generating decoded output data. The method includes receiving encoded data (,) while data already received is processed iteratively by decoder processors in a pipelined fashion. Decoder processors are designated to perform particular iterations (,) of an iterative decoding process which are performed simultaneously. As a decoder processor completes processing its designated iteration on a block of data, the decoder processor outputs decoding information (,) to the decoding processor designated to perform the subsequent iteration. Upon completion of all iterations for a block of data, the method includes generating output (,) consisting of the decoded data block. The method provides that once processing is complete on a data block, the memory block is made available (,) for the storing of new encoded input data.

Pipelined architecture to decode parallel and serial concatenated codes

An error correction encoding system (,) is provided for use in an in-flight programmable spacecraft. The error correction encoding system (,) includes a first data routing switch (,) which receives an uncoded data stream and directs the uncoded data stream to either of a first encoding device (,) or a second encoding device (,). The first encoding device (,) receives the uncoded data stream from the first data routing switch (,) and applies a first encoding function. Alternatively, the second encoding device (,), having a plurality of programmable logic blocks, receives the uncoded data stream from the first data routing switch (,) and applies a second encoding function. A controller (,) is connected to the second encoding device (,) for configuring the plurality of programmable logic blocks to perform the second encoding function. Lastly, a second data routing switch (,) receives a coded data stream from either of the first encoding device (,) or the second encoding device (,) and outputs a coded data stream.

In-flight programmable spacecraft error correction encoder

A communications system (100) is disclosed for processing at least one uplink channel contained in at least one uplink beam (112) transmitted to a satellite (106). The communications system (100) includes at least one user terminal (110) that extracts a system clock, a synchronization word, and timing correction information from a downlink beam transmitted by a satellite. The user terminal includes a timing controller (226) that aligns uplink channel transmissions by generating a system clock based on the downlink symbol clock, said synchronization word, and said timing correction information. The user terminal includes at least one spread-spectrum spreader (254) for encoding at least one uplink channel, and a transmitter connected to the spread-spectrum spreader (254) for transmitting said at least one uplink channel in an uplink beam (112). The system also includes a satellite (106) which generates the synchronization word, downlink symbol clock, and the timing correction information needed by the user terminal. The satellite also includes a wideband FFT processor (322) that extracts uplink channels from the uplink beam (112) in bulk, and a despreader (326) connected to the FFT processor (322) for simultaneously despreading user signals contained in said uplink channels.

Bulk despreading of multiple independent CDMA sources

A method for reducing interference and increasing spectral efficiency in a frequency reuse pattern (600) is disclosed. The method includes the steps of generating n original communications beams (302-308) assigned to substantially non-overlapping frequency bands, with the original communications beams extending over a first set of predetermined bandwidths. The method also generates n shifted communications beams (402-408) shifted by an orthogonal frequency separation from the n original communications beams (302-308), with the n shifted communications beams (402-408) extending over a second set of predetermined bandwidths. The method projects the n original communications beams (302-308) and the n shifted communications beams (402-408) in a frequency reuse pattern (600) over a region of interest by alternating the n original communications beams (302-308) with the n shifted communications beams (402-408).

Method for reducing interference and increasing spectral efficiency

A satellite communications technique is disclosed that synchronizes the reception of numerous OFDM uplink signals (108, 110) at a satellite (106) receiver and bulk processes them in the satellite (106). In operation, the satellite (106) receives an OFDM uplink signal (110) transmitted by a CPE (104). The satellite 106 then compares the reception timing of the symbols in the received OFDM uplink signal (110) with a satellite timing reference, and generates a timing correction. The satellite (106) provides a downlink symbol clock as inherent structure in a downlink beam to the CPE (104) and also transmits the timing correction in the downlink beam. The CPE (104) uses the downlink symbol clock in conjunction with the timing correction to generate an uplink clock. The CPE (104) then transmits data in the OFDM uplink signal (110) synchronously with the uplink clock. Each CPE (102, 104) may be synchronized in this manner. In addition, the satellite (106) may also periodically re-compare the reception timing of the OFDM uplink signals (108, 110) with the satellite timing reference to generate new timing corrections, if necessary, for the CPEs (102, 104).

Bulk filtering and demodulation of independent FDMA sources

A method is disclosed for efficiently transmitting large numbers of data channels through a satellite (24). The method uses a block encoder (28) that encodes the data channels with a block code to produce an encoded uplink data stream. A modulator (30) modulates the encoded uplink data stream. A transmit antenna (32) then sends the resultant modulated uplink data stream (34) to the satellite (24). The satellite uses a satellite demodulator (48) and a switch (50) to produce an internal data stream consisting of selected data channels in the uplink data stream (34). The internal data stream is fed into a convolutional encoder (52). The output of the convolutional encoder (52) is connected to a satellite modulator (54). The satellite transmit antenna (56) then sends the resultant modulated downlink data stream (58) to a receiver.

High efficiency signaling with minimum spacecraft hardware

A method is disclosed for adding a geostationary component (201) to a low earth orbit satellite network. The method includes establishing a geostationary orbit for an administration satellite, providing an East-West communications link (218) between a low earth orbit satellite (202) at a polar location and the administration satellite and providing an RF link (216) between a ground based network control center (214) on the ground and the administration satellite. The method also includes the steps of transmitting administration information received by the administration satellite over the RF link (216) from the administration satellite to the low earth orbit satellite (202) over the East-West communications link (218).

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Los Angeles, CA, United States of America

Oliver W Saunders