Wireless packet data distributed communications system

• US 20020089956A1
• Filed: 03/13/2002
• Published: 07/11/2002
• Est. Priority Date: 12/07/1995
• Status: Active Grant

• Current Assignee: 2201028 Ontario Incorporated
• Original Assignee: Transcore Link Logistics Corporation (Roper Technologies, Inc.)
• Inventors: Seed, William Robert, Haugli, Hans-Christian
• Granted Patent: US 7,142,521 B2
• Time in Patent Office: Days
• US Class Current: 370/335
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system
• CPC Class Codes: H04B 7/216 Code division or spread-spectrum multiple access [CDMA, SSMA]
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A two-way satellite communications system includes an Earth station communicating with a plurality of remote terminals using a network access protocol that facilitates low power consumption by the terminals. The earth station generates forward link TDM packet data transmissions on one or-more satellite channels, and detects, despreads and decodes multiple concurrent return link slotted CDMA packet transmissions on one or more satellite channels. It communicates through a wired connection with a packet processing center which ultimately both delivers return link packet data to end-customers and receives forward link packet data from end-customers. The remote terminals receive, process and act upon forward link TDM transmissions on one or more satellite channels, and generate slotted spread spectrum CDMA transmissions on the return link on one or more satellite channels. The remote terminals communicate with a local digital data source and/or sink, digitize one or more local analog sensor signals, enter into a sleep mode to minimize the terminal'"'"'s power consumption, and access the satellite communications network in accordance with the system network access protocol.

Claims

1. A method of establishing packet data communication between a central station and a plurality of remote units via multiple beam satellite, comprising transmitting packets over a TMD forward link to said remote units, transmitting packets from said remote units back to the control station over a slotted CMDA return link, and switching beams to increase efficiency of satellite usage.

2. A method as claimed in claim 1, wherein each said remote unit is allocated a particular subframe in the TDM forward link and a particular satellite beam so as to permit the same subframe to be used by other units in different beams.

3. A method as claimed in claim 1, wherein a beam identifier for each remote unit is stored at said control station.