Abstract: An electronic document delivery system and method in which a broadcast center periodically sends a “catalog” of available documents to a receiving computer, thereby allowing a user to browse through the available documents without having to access the broadcast center. The documents are transmitted as packets, and the packets are decrypted as soon as they are received, eliminating the need to store both an encrypted and an decrypted version of the documents at the receiving computer. The receiving computer periodically receives information allowing it to decrypt received documents and to encrypt billing information for the receiving computer. The invention is not limited to text-only documents and can receive all types of documents, such as software, images, text, and full-motion video.

Abstract: An approach for minimizing variation in transmit power of synchronized signals that are destined to a satellite is disclosed. A gateway station system for communicating with a communication satellite includes a multiple signal sources which generate the synchronized signals. The gateway station system utilizes a control logic that is coupled to the signal sources. The control logic operates to offset selectively transmission times of a portion of the synchronized signals according to a predetermined distribution and an offset period. The predetermined distribution specifies about half the number of the synchronized signals are to be offset. The offset period is half a symbol period. The terminals within the satellite communication system has a receiver that receives the synchronized signal from the communication satellite.

Abstract: An approach for identifying a particular carrier among a plurality of carriers in a satellite communication system is disclosed. A transmitter multiplies an encoded signal by a prescribed periodic sequence to form a watermarked signal and transmits the watermarked signal associated with a particular carrier over a communication channel. A receiver tunes to one of the carriers and extracts a data sequence from the one carrier. The receiver multiplies the data sequence with the prescribed periodic sequence to form another watermarked signal and determines whether the watermarked signals match.

Abstract: A method and apparatus for generating a database in a memory. Program identifying information is received from a service provider, the program identifying information comprising at least one service provider search criteria and information describing a channel on which a program is transmitted. A database is generated in a memory as a function of the channel identifying information and at least one of the service provider search criteria. Preferably, user-input search criteria is also received and it is determined whether the user-input search criteria corresponds to the service provider search criteria. A channel identified by the channel identifying information is selected if the user-input search criteria corresponds to the service provider search criteria.

Abstract: A system in which a personal computer sends messages into a TCP/IP network using a conventional dial-up link and downloads data from the TCP/IP network using a high-speed one-way satelite link. A preferred embodiment uses a conventional SLIP provider to connect to the TCP/IP network and uses a commercial software TCP/IP package that has a standard driver interface. A spoofing protocol compensates for the long propagation delays inherent to satellite communication.

Abstract: A radio, and related methods of radio communication, consisting of one or more signal formatters, wherein the one or more signal formatters format signals for transmission through the radio and the signals comprise a plurality of transport mode signals. The radio also includes a modem coupled to the one or more signal formatters for modulating the signals, a frequency converter coupled to the modem for upconverting the signals having been modulated to a radio frequency, and a transceiver unit coupled to the frequency converter for transmitting the signals having been upconverted over a radio communications link.

Abstract: A method and apparatus for interleaving an input data stream for parsed parallel concatenated code encoding, the method comprising the steps of: parsing the input data stream into a plurality of parsed data substreams; and forming sets of shared information bits, wherein each of the sets of shared information bits comprises information bits in common with respective pairs of the plurality of parsed data substreams. In a variation, a further step comprises constructing constituent permutations of one or more of the sets of shared information bits. In yet a further variation, a further step comprises interlacing respective pairs of the sets of shared information bits to form respective interleaved data substreams.

Abstract: A system determines a voicing measure as a measure of the degree of signal periodicity and uses the determined voicing measure to quantize the spectral magnitude of the slowly evolving waveform (SEW) and the modeling of the SEW and rapidly evolving waveform (REW) phase spectra.

Abstract: A method, apparatus and computer program product for encoding data transmitted over a communications channel, including pre-loading an encoder dictionary with a set of character strings expected to appear in input data to be encoded; and encoding the input data with the set of expected character strings pre-loaded in the encoder dictionary. In another aspect, there is provided a method, apparatus and computer program product for decoding encoded data received over a communications channel, including pre-loading a decoder dictionary with a set of character strings expected to appear in the encoded data; and decoding the encoded data with the set of expected character strings pre-loaded in the decoder dictionary.

Abstract: An apparatus for generating a modulated signal which includes a modulator operative for receiving a first signal and input data signals, and modulating the first signal in accordance with the input data signals so as to produce a modulated reference signal; a first frequency divider coupled to the modulator output, operative to reduce the frequency of the modulated reference signal by a predetermined factor; a signal generator operative to produce a second signal; a first mixer having a first input coupled to an output of the first frequency divider and a second input coupled to the output of the signal generator. The first mixer operates to frequency translate the modulated reference signal by an amount equal to the frequency of the second signal. In addition, the signal generator of the present invention contains a direct digital synthesizer coupled to a second phase lock loop which operates to up-convert the output signal of the DDS to the microwave region.

Abstract: A method for estimating and compensating for a fading communications channel includes the steps of generating matched filter data from a received data burst, interpolating between reference symbols to generate a fading channel estimate from the matched filter data, applying a phase correction to the matched filter data from the fading channel estimate to recover free data from the matched filter data, and performing decision feedback on the free data to improve the fading channel estimate.

Abstract: General binary design criteria for PSK-modulated space-time codes are provided. For linear binary PSK (BPSK) codes and quadrature PSK (QPSK) codes, the rank (i.e., binary projections) of the unmodulated code words, as binary matrices over the binary field, is used as a design criterion. Fundamental code constructions for both quasi-static and time-varying channels are provided.

Abstract: An encoder, decoder, method of encoding, and method of decoding which preserves the turbo coder performance in the waterfall region, while improving upon performance in the error asymptote region, by applying a parser or other similar element to the input bit stream. The parser assigns input bits to a subset of constituent encoders in a pseudo-random fashion. The parsing strategy breaks up input sequences producing low Hamming weight error events, thereby improving the weight spectrum and asymptotic performance of the code, while not impacting waterfall region performance. The parser or other similar element may also strengthen the weight spectrum without adversely affecting convergence of a corresponding decoder.

Abstract: A system in which a personal computer sends messages into a TCP/IP network using a conventional dial-up link and downloads data from the TCP/IP network using a high-speed one-way satellite link. A preferred embodiment uses a conventional SLIP provider to connect to the TCP/IP network and uses a commercial software TCP/IP package that has a standard driver interface. A spoofing protocol compensates for the long propagation delays inherent to satellite communication.

Abstract: A combined interference cancellation communication system employing forward error code (FEC) decoding for high spectral efficiency satellite communications. The disclosed system enables efficient utilization of available bandwidth through overlapping adjacent channels. A receiver is used to receive a waveform having data information and noise information. A filter bank is coupled with the receiver to receive and filter waveform and output channel information received by the receiver. The channel information received includes a combination of data signals and adjacent channel interference signals. Soft-input and soft-output decoders are provided to receive the channel information in order to calculate an estimated interference value. Additionally, the soft-input and soft-output interference canceler is provided for receiving the output channel information and the estimated interference value calculated from the decoders in order to provide a relatively more accurate estimated data signal.

Abstract: A method of providing forward error correction for data services uses a parallel concatenated convolutional code which is a Turbo Code comprising a plurality of eight-state constituent encoders wherein a plurality of data block sizes are used in conjunction with said Turbo Code. A variation uses the method in a cellular radio system. Another variation uses the method in both forward and reverse likes of a cellular radio system.

Abstract: A system and method for integrating advanced messaging capabilities in a wide area wireless personal communications system is provided. The system includes personal transceiver units capable of communicating with one or more of a plurality of long range pagers. The transceiver and long range pager use existing frequencies and formats of the wireless personal communications system. The method provides for registering a personal transceiver in a two way messaging service area of the wireless personal communications system.

Abstract: A communication system including an upstream proxy server and two reporting downstream proxy servers, where the upstream proxy server is capable of multicasting a uniform resource locator (URL) to the reporting downstream proxy servers, the reporting downstream proxy servers interact with the upstream proxy server to resolve cache misses and the upstream proxy servers returns a resolution to a cache miss via multicast. A downstream proxy server which filters multicast transmissions of URLs and stores a subset of the URLs for subsequent transmission, where relative popularity is used to determine whether to store a multicast URL. An upstream proxy server capable of multicasting URLs to reporting downstream proxy servers, where the upstream proxy server interacts with the two reporting downstream proxy servers to resolve cache misses and the upstream proxy server returns a resolution to the cache misses via multicast.

Abstract: An extension system, and related methods, for extending the location of interfaces and expanding the number of interface modules that interface with a communications system. The system includes a communications terminal including a first multi-transport mode bus that carries signals comprising a plurality of transport mode signals, a plurality of interface ports coupled to the first multi-transport mode bus, and a first extension interface mode coupled to one of the plurality of interface ports, wherein the first extension interface module converts the transmission format of the signals to a transmission format of an extension communications link.

Abstract: A system for managing return channel bandwidth in a two-way satellite communication network is disclosed. A plurality of transceivers are configured to transmit backlog information over a return channel via a satellite. The backlog information specifies an amount of queued traffic for the respective transceivers. A hub is configured to receive the backlog information and to allocate a predetermined amount of return channel bandwidth to each of the plurality of transceivers. The hub determines whether additional return channel bandwidth is available to accommodate a remaining backlog such that a bandwidth allocation amount is set to a level associated with one of the plurality of transceivers having the largest backlog. The hub selectively identifies a transceiver among the plurality of transceivers having a next largest backlog based upon the determined available return channel bandwidth.