Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Satellite communication systems are provided that employ highly inclined, highly elliptical orbits. The satellite communication systems have a satellite constellation phased to provide a ground trace with respect to the earth that is repeated by each of the satellites in the constellation such that the satellites appear to follow one another over similar paths over the earth. Due to the path of the ground trace provided, ground stations can employ a single axis tracking device since the satellites appear to move along similar overlapping paths in opposing directions relative to a user on the ground during communication control handoffs.

Abstract: 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.

Abstract: A communication subsystem (300) for transmitting error correction coded data in packets (200) includes an input buffer (302) storing unencoded data, a product coder (304) coupled to the input buffer, and a time division transmitter (306). The product coder (304) outputs product coded data packets (200) having a packet size, and the time division transmitter (306) transmits the product coded data packets (200) in a data section (109) of a frame (104). The data section (109) has a length substantially equal to an integer multiple of the packet size. The communication subsystem (300) may use a (s, t)×(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 (402), product coding the unencoded data (404), and outputting product coded data packets (406) having a packet size.

Abstract: Techniques for trading satellite communication resources include a net work operations controller 80 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 10 receives information from the network operations controller 80 and configures a switch 50 in the satellite, as well as the downlink schedule, in order to enable data communications through the satellite by the winning bidder.

Abstract: Apparatus for enhancing the processing capabilities of a satellite communication system including an uplink receiver 40 deployable with a first satellite 20. A first processor 50 deployable on satellite 20 is capable of processing signals from uplink receiver 40. A link terminal 60 deployable with satellite 20 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 100 deployable with satellite 20 enables signals from uplink receiver 40 to be utilized by communication link terminal 60 or processor 50. A downlink transmitter 80 deployable with satellite 20 is capable of transmitting signals to a ground based communication station 90. A second switch 110 deployable with satellite 20 enables signals from communication link terminal 60 or first processor 50 to be utilized by downlink transmitter 80.

Abstract: A caching subsystem and method for a communication satellite includes an uplink demodulator that produces demodulated data on a demodulated data output for storage in a memory cache. This also includes a switched-router coupled to the solid state recorder. A processor outputs a first preselected time delay control signal to the memory cache to generate a first time delayed data stream. In addition, the processor subsequently outputs a second preselected time delay control signal to the solid state recorder to generate a second time delayed data stream. The solid state recorder and processor act in concert to provide a variable time delay pipeline for program data. The uplink demodulator also produces a program data identifier and a delivery request. The processor outputs a control signal to the solid state recorder to generate independent downlink data streams from the program data at delivery times and delivery dates specified by delivery requests.

Abstract: Apparatus for enhancing the communication capabilities of a satellite communication system including an uplink receiver 40 deployable with a first satellite 20 and capable of receiving signals from a ground-based communication station 30. A first processor 50 deployable on satellite 20 is capable of processing signals from uplink receiver 40. A two-way link terminal 60 deployable with satellite 20 is capable of communication with a second two-way intersatellite communication link terminal 220 deployable with a second satellite 200. A first switch 100 deployable with satellite 20 enables signals from uplink receiver 40 to be utilized by communication link terminal 60 or processor 50. A downlink transmitter 80 deployable with satellite 20 is capable of transmitting signals to a ground-based communication station 90. A second switch 110 deployable with satellite 20 enables signals from communication link terminal 60 or first processor 50 to be utilized by downlink transmitter 80.

Abstract: An antenna system that includes one or more antenna feed horns (30), where each feed horn (30) includes a plurality of micro-mechanical devices (38) positioned around the aperture (32) of the feed horn (30). The micro-mechanical devices (38) are linear motion devices that can be activated to extend a conductive surface (40) beyond the end of the feed horn (30). By selectively actuating groups of the micro-mechanical devices (38) to extend the conductive surfaces (40), the end of the feed horn (30) can be changed to provide different asymmetrical configurations, causing the beam direction to change accordingly. The micro-mechanical devices (38) can be any suitable mechanical device, such as MEMS devices or carbon nanotube artificial muscles.

Abstract: The present invention provides a method and apparatus (400) for iteratively decoding data which has been encoded with contatenated codes. The apparatus (400) includes pipelined and cascaded decoder processors (406, 430 and 436) connected to a multiple block memory device (402), through a multiplexing and data control block (404). A data decision element (437) is provided for generating decoded output data. The method includes receiving encoded data (802) while data already received is processed iteratively by decoder processors in a pipelined fashion. Decoder processors are designated to perform particular iterations (810) 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 (808) to the decoding processor designated to perform the subsequent iteration.

Abstract: An error correction encoding system (20) is provided for use in an in-flight programmable spacecraft. The error correction encoding system (20) includes a first data routing switch (22) which receives an uncoded data stream and directs the uncoded data stream to either of a first encoding device (26) or a second encoding device (24). The first encoding device (26) receives the uncoded data stream from the first data routing switch (22) and applies a first encoding function. Alternatively, the second encoding device (24), having a plurality of programmable logic blocks, receives the uncoded data stream from the first data routing switch (22) and applies a second encoding function. A controller (30) is connected to the second encoding device (24) for configuring the plurality of programmable logic blocks to perform the second encoding function.

Abstract: 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).

Abstract: 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).

Abstract: 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.

Abstract: 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.

Abstract: 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).