Abstract: A cellular telephone network comprises peripheral branches and a central high-capacity data trunking region or network backbone. The invention concerns effective utilization of trunking capacity to provide backbone facilities for such a network. The network backbone comprises a satellite interface for a satellite connection and alternatively or additionally a backup backbone route. For example an Internet backbone route and a satellite backbone route may be used, one backing up the other.

Abstract: Two-way data communication via satellite, using data communication in a first direction via satellites in geostationary orbit, and a data communication in a second direction via satellites in a below geostationary orbit, either MEO or LEO. The transceiver is particularly useful for providing Internet connections Preferably, a LEO forward link may be used for control signaling, urgent data traffic and the like.

Abstract: A satellite modem whose baseband modules can be implemented mostly in software running on a suitable processor such as a high speed digital signal processor (DSP). The modem includes a RF portion and a baseband portion. The digitized output of a matched filter is input to the baseband processing portion that consists of software executing on a DSP. The modem comprises an antenna coupled to an upconverter/downconverter. The upconverter/downconverter is coupled to a RF transceiver which functions to receive a transmit signal from a baseband transmitter module and generate a signal for input to the upconverter/downconverter. The RF transceiver also functions to receive a downconverted signal and output an IF signal for input to an IF module. The IF functions to generate I and Q outputs that are input to a digital baseband module. The baseband module can be implemented as software executing on a DSP. Also included in a technique of modulation wipe off wherein the effects of modulation are removed.

Abstract: A cellular telephone network comprises peripheral branches and a central high-capacity data trunking region or network backbone. The invention concerns effective utilization of trunking capacity to provide backbone facilities for such a network. The network backbone comprises a satellite interface for a satellite connection and alternatively or additionally a backup backbone route. For example an Internet backbone route and a satellite backbone route may be used, one backing up the other.

Abstract: A frequency synthesizer includes a direct digital synthesizer (DDS), a digital-to-analog converter for converting the output of the DDS to a DDS output signal, a first bandpass filter for filtering the DDS output signal, a single side band mixer for mixing the filtered DDS output signal with a mixing frequency signal, a divider for dividing the mixer output, a second bandpass filter for filtering the mixer output, and a phase lock loop for turning the filtered mixer output into a signal of the desired frequency. This frequency synthesizer combines the high resolution of a DDS with high bandwidth and low noise.

Abstract: A method of filtering a signal, the method including the steps of sampling analog input signal, thereby providing a purality of digital complex input signal samples the each of the samples indicates a sign and a magnitude, for each of the complex input signal samples demultiplexing the complex input signal sample into a first sign component and a first magnitude component, performing a logarithmic conversion on the first magnitude component, thereby resulting in a first logarithmic value, demultiplexing a complex coefficient into a second sign component and a second magnitude component, performing a logarithmic conversion on the second magnitude component, thereby resulting in a second logarithmic value, adding the first and second logarithmic values, thereby resulting in a third logarithmic value, performing an antilog conversion on the third logarithmic value, thereby resulting in an antilog value, XORing the first and second sign components, thereby resulting in an output sign, providing the antilog value

Abstract: Two-way data communication via satellite, using data communication in a first direction via satellites in geostationary orbit, and a data communication in a second direction via satellites in a below geostationary orbit, either MEO or LEO. The transceiver is particularly useful for providing Internet connections Preferably, a LEO forward link may be used for control signaling, urgent data traffic and the like.

Abstract: The present invention is a return link for a satellite communication system. The return link described herein is suitable for use in any type of communications network such as networks used for Internet access purposes. The return link in combination with a forward link forms a complete two way communication system via satellite. The return link comprises two separate communication schemes used in combination to implement the return link of the satellite system. The first communication scheme uses a random access method based on a non synchronous frequency hopping code division multiple access technique (NS/FH/CDMA). The second communication scheme uses a channel assignment method based on a frequency division multiple access (FDMA) technique. Data generated by a user is transmitted utilizing one of the two communication schemes in accordance with the content and amount of data generated.