Satellite communication system employing a combination of time division multiplexing and non-orthogonal pseudorandom noise codes and time slots

Abstract

An improved satellite communication system is provided comprising at least one satellite wherein each satellite provides multiple beams, a plurality of UTs, and at least one gateway connected to a PSTN and communicating with said at least one UT or with a constellation, wherein each of the UTs within a given frequency band is distinguished from another of the UTs employing a combination of TDM and NOPN codes and time slots.

1 . A satellite communication system for communicating between a plurality of user terminals comprising:
 at least one satellite which provides multiple beams;   a plurality of user terminals that communicate with each other, or a public switched telephone network or a data network, via said at least one satellite; and   at least one gateway connected to the public switched telephone network and/or the data network and communicating with at least one user terminal over at least one satellite,   wherein each of said user terminals within a given frequency band of the satellite communication system is distinguished from another of said user terminals employing a combination of time division multiplexing and only non-orthogonal pseudorandom noise codes and time slots where each of the time slots includes only the non-orthogonal pseudorandom noise codes to distinguish each of said user terminals;   wherein each of said user terminals is equipped to initiate or receive or terminate packet data messages;   wherein each of said user terminals is handed off from one beam of a satellite to another beam of said satellite;   wherein said hand off is predicated on signal strength determined at said plurality of user terminals, and   wherein said user terminals located in a satellite beam are distinguished from user terminals located in an adjacent satellite beam assigned to an identical time slot by a different scrambling code for each beam, comprising a pseudorandom noise sequence uniquely assigned to each beam.   
     
     
         2 . The satellite communication system as defined in  claim 1 , wherein said time division multiplexing and non-orthogonal pseudorandom noise codes are implemented in a forward and return link. 
     
     
         3 . The satellite communication system as defined in  claim 2 , wherein said forward link comprises time division multiplexing and said return link uses non-orthogonal pseudorandom noise codes and time slots to distinguish users. 
     
     
         4 . The satellite communication system as defined in  claim 1 , wherein said at least one satellite comprises a LEO constellation satellite system. 
     
     
         5 . The communication satellite system as defined in  claim 1 , wherein said satellite system comprises a MEO satellite system. 
     
     
         6 . The satellite communication system as defined in  claim 1 , wherein said at least one satellite comprises a GEO satellite constellation. 
     
     
         7 . A satellite communication system for communicating between a plurality of user terminals comprising:
 at least one satellite which provides multiple beams;   a plurality of user terminals that communicate with each other, or a public switched telephone network or a data network, via said at least one satellite; and   at least one gateway connected to the public switched telephone network and/or the data network and communicating with at least one user terminal over at least one satellite,   wherein each of said user terminals within a given frequency band of the satellite communication system is distinguished from another of said user terminals employing a combination of time division multiplexing and only non-orthogonal pseudorandom noise codes and time slots where each of the time slots includes only the non-orthogonal pseudorandom noise codes to distinguish each of said user terminals;   a ground operations control center which provides tracking information over a ground portion of the data network as to which satellites of the system to use and transmission parameters including transmit power and frequencies to use for communication between the plurality of user terminals, and which antenna to use;   wherein said user terminal is equipped to initiate or receive or terminate packet data messages;   wherein said user terminal uses tracking information provided by the ground operations control center to optimize its signal transmission and reception parameters;   wherein said user terminals located in a satellite beam are distinguished from user terminals located in an adjacent satellite beam assigned to an identical time slot by a different scrambling code for each beam, comprising a pseudorandom noise sequence uniquely assigned to each beam.   
     
     
         8 . The satellite communication system of  claim 7 , wherein said satellites are in a LEO satellite constellation.