Shiron Satellite Communications (1996) Ltd.

Sorin Goldenberg

Alexander Pokrass

Shaul Laufer

Arie Reichman

Jeffrey Davidson

Israel Shahaf Wayer

Avi Barda

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. A signal detection technique performs signal detection and frequency acquisition in the presence of multiple signals in accordance with a method described hereinbelow. A timing acquisition technique includes an unwrapping technique that functions to correct timing errors before averaging is performed. Linear changes to the time estimates are performed using LSR techniques.

Variable rate continuous mode satellite modem

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. Messages requiring a relatively low transmission rate, such as short bursty messages, utilize the random access transmission method. On the other hand, messages requiring a higher transmission rate, such as video conferencing, utilize the channel assignment method.

Reverse link for a satellite communication network

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Petach Tikva, Israel

Sorin Goldenberg