Abstract: An approach is provided for decoding a low density parity check (LDPC) coded signal. Edge values associated with a structured parity check matrix used to generate the LDPC coded signal are retrieved from memory. The edge values specify the relationship of bit nodes and check nodes, and are stored within memory according to a predetermined scheme that permits concurrent retrieval of a set of the edge values. A decoded signal corresponding to the LDPC coded signal is output based on the retrieved edge values.

Abstract: A method and apparatus for storing and retrieving program material for subsequent replay is disclosed.

Abstract: A method and apparatus for storing and retrieving program material for subsequent replay is disclosed.

Abstract: A method and apparatus for receiving signals transmitted from a plurality of communications satellites. An apparatus in accordance with the present invention comprises a reflecting surface having a focal point, and a plurality of low noise block down converters with feedhorns (LNBFs), each LNBF having a boresight, wherein at least a first LNBF receives signals in a first frequency band transmitted from a first communication satellite location that are focused at a first focal point and at least a second LNBF receives signals in a second frequency band transmitted from a second satellite location that are focused at a second focal point, wherein the boresight of the first LNBF is closer to the first focal point than the boresight of the second LNBF is to the second focal point.

Abstract: A communications system (10) and method of operating the communications system includes a first stratospheric platform generating a second beam having a frequency the same as a satellite beam to the same service area. User terminals are configured to receive the first beam or the second beam.

Abstract: A method and system for maximizing satellite coverage at predetermined local times for a set of predetermined geographic location includes a processor operative to determine a period of rotation for each of the desired satellites in the satellite constellation. The processor also determines a time dependent coverage of the satellite constellation based on the period of rotation and the trajectory of each of the desired satellites. The trajectories of the desired satellites are tilted until the satellite constellation provides maximum coverage at the predetermined local times for the set of predetermined geographic locations. If a new satellite constellation is being designed, command signals are programmed into a computer of a launch vehicle containing the modified trajectory. If an existing satellite constellation is being modified, the ground station transmits command signals to the satellites for modifying the trajectory of the satellites in accordance with the tilted trajectory.

Abstract: The present invention relates to a smart card reader (10) that enables a user to insert a smart card (20) into an open receptacle (15) that includes tabs (16) or a lip (32) that resiliently holds the smart card (20) within the receptacle (15). The present invention provides users a novel and useful design to reduce smart card abrasion as opposed to the card readers of the prior art. The present invention relates to a card reader (10) for usage with a smart card (20) comprising: a receptacle (15), where the receptacle (15) includes at least one open side; at least one placement tab (16), where the at least one placement tab (16) extends into the receptacle (15) and secures the placement of the smart card (20) in the receptacle (15); and a plurality of contacts (18) residing within the receptacle (15) where the plurality of contacts (18) connect to a smart chip (22) within the smart card (20) upon placement of the smart card (20) in the receptacle (15).

Abstract: Data is received by a service provider that is indicative of a selected server-side system and a selected client-side system between which a VPN is to be established. Security settings are then automatically determined for the client-side system based at least partially on the data. The security settings are preferably public and private keys and/or a Digital Certificate. VPN configuration details, including the security settings, are then automatically transmitted to the client-side system. The client side system then uses the configuration details to automatically configure itself to establish a secure VPN tunnel between the server-side system and itself. VPN configuration details may also be automatically transmitted to a VPN concentrator within the server-side system. A Virtual Private Network tunnel is subsequently established between the client-side system and the server-side system, and the tunnel's operation verified. A computer program product for configuring a VPN system is also provided.

Abstract: A method and system for controlling a movable appendage on an aerospace vehicle independent from the position of the aerospace vehicle. First and second beacons containing actual position information for the movable appendage are tracked and acquired by first and second beacon tracking sites. The beacon tracking sites report the azimuth and elevation data relating to the position of the movable appendage to a processor where a correction command is determined based on an error calculated from the position data and a desired position. The correction command is communicated to the movable appendage so that appropriate correction to the desired position can be made.

Abstract: An approach is provided for a method of encoding structure Low Density Parity Check (LDPC) codes. Memory storing information representing a structured parity check matrix of Low Density Parity Check (LDPC) codes is accessed during the encoding process. The information is organized in tabular form, wherein each row represents occurrences of one values within a first column of a group of columns of the parity check matrix. The rows correspond to groups of columns of the parity check matrix, wherein subsequent columns within each of the groups are derived according to a predetermined operation. An LDPC coded signal is output based on the stored information representing the parity check matrix.

Abstract: A system and method for adapting program guides to meet subscriber criteria, and for providing program guide information to selected subscribers based upon subscriber criteria such as the subscriber's location within a market area is disclosed. In one embodiment, the method is applied to a system broadcasting a first signal having service channels, each of which service channels is uniquely described by a service channel identifier. The application of the method provides second program guide information describing a second set of programs only to a subset of the plurality of receiver stations that comply with at least one service criteria.

Abstract: A communication system has a first plurality of wireless basestations having adaptive antennas with a plurality of main array antenna elements for generating a plurality of communication beams. The system further includes a gateway station coupled to the first plurality of wireless basestations. The gateway station forms a plurality of beam commands by communicating a plurality of control signals to the first plurality of wireless basestations to form the communication beams. A second plurality of wireless base stations having a second plurality of adaptive antennas with a second plurality of main array antenna elements for generating a plurality of communication beams to communicate with said mobile user and a fixed user. The beams include a first link and a second link from the first plurality of basestations that communicate with the fixed user terminal and a third link and fourth link from the second plurality of wireless basestations to communicate with the mobile user terminal.

Abstract: A method and apparatus for equalizing digital data signals is disclosed. The method comprises the steps of demodulating and decoding an input signal having input data to produce a data output, remodulating the data output to produce a training sequence including an idealized input signal, wherein the training sequence is comprised of adjacent symbols in the input data, and generating equalizer parameters from the training sequence. The apparatus comprises a demodulator (for demodulating an input signal to produce a data output), a modulator communicatively coupled to the demodulator (for remodulating the data output to produce a training sequence including an idealized input signal wherein the training sequence is comprised of adjacent symbols in the input data), and a parameter generation module communicatively coupled to the modulator (for generating equalizer parameters from the training sequence).

Abstract: A method and apparatus for optimizing a system for transmitting a layered modulated signal is disclosed. The method comprises the steps of defining the system in terms of a set of system parameters, including an optimal power separation S between a power of a first modulation layer and a power of a second modulation layer and a required system carrier-to-noise ratio (CNRS), determining an optimal power separation S to minimize the error rate of a lower layer modulated signal BERL, and selecting the remaining system parameters in the set of system parameters using the determined optimal power separation S.

Abstract: A communication system has a plurality of ground stations for communicating communication signal to a plurality of satellites located in an inclined elliptical sub-geosynchronous orbit with respect to the earth. The plurality of satellites operate in a service area in a synchronized manner to provide continuous coverage to the service area. The satellites generate a plurality of beams with variable beamwidths to obtain a substantially uniform cell size covering the service area. A user terminal within the service area receives communication signals from the satellite.

Abstract: A communication system has a plurality of bases stations generating communication portions from a base station communication signal. The plurality of base stations are capable of using the entire allocated bandwidth to generate the base station communication portions. A user terminal establishes a plurality of dynamic links corresponding respectively to the plurality of base stations. The user terminal generates multiple communication portions of a user signal and transmits the multiple communication portions through the dynamic links to the plurality of base stations. The user terminal receives the base station communication portions from the plurality of bases stations and reassembles the communication portions into the base station communication signals.

Abstract: A communication system for transmitting encoded signals over a communication channel is disclosed. The system includes a transmitter, which has a source that is configured to output a plurality of input signals. The transmitter also includes an encoder that is configured to generate a plurality of output signals in response to the plurality of the input signals to output a code word according to the plurality of output signals, wherein the code word has a predetermined algebraic construction for space-frequency coding based upon the communication channel being characterized as a frequency selective block fading channel. Further, the transmitter includes a modulator that is configured to modulate the code word for transmission over the communication channel, and a plurality of transmit antennas that configured to transmit the modulated code word over the communication channel.

Abstract: Systems and methods for receiving layered modulation for digital signals are presented. An exemplary apparatus comprises a tuner for receiving a layered signal and producing a layered in-phase signal and a layered quadrature signal therefrom, an analog-to-digital converter for digitizing the layered in-phase signal and the layered quadrature signal and a processor for decoding the layered in-phase signal and the layered quadrature signal to produce one or more discrete layer signals.

Abstract: A method and apparatus transmitting a layered modulation signal having a first signal layer having first signal symbols and a second signal layer having second signal symbols is disclosed. The method comprises the steps of determining a first signal layer modulation carrier power CL at least in part according to a first signal layer clear sky margin ML and a first signal layer availability, determining an second signal layer modulation carrier power CU at least in part according to an second signal layer clear sky margin MU and an second signal layer availability, modulating the first signal symbols according to a first carrier at the determined first signal layer modulation carrier power; modulating the second signal symbols according to a second carrier at the determined second signal layer modulation carrier power, and transmitting the two layers independently.

Abstract: An improved satellite communication device and system are provided. The satellite communication device uses yaw or roll-yaw steering to linearize angular track of uplink cells; one-dimensional linear “ratcheting” in an uplink antenna to maintain resource allocation of uplink cells along antenna columns; phased-array downlink antennas which can track earth-fixed downlink cells while compensating for the yaw (or roll-yaw) satellite steering; and variable rate TDMA service among downlink cells in a footprint. As a result, system overhead for performing new resource allocations between satellite handovers is minimized, thereby reducing resource management and increasing system capacity. Flexible bandwidth/capacity assignment of both uplink and downlink resources to earth locations via linear cell ratcheting, uplink RF peaking switch, and data-driven variable-TDMA downlink phased-arrays, is provided.