ADAPTIVE DATA RATE CONTROL FOR NARROWCAST NETWORKS

• US 20110141938A1
• Filed: 02/18/2011
• Published: 06/16/2011
• Est. Priority Date: 08/16/1999
• Status: Active Grant

• Current Assignee: ViaSat Incorporated
• Original Assignee: ViaSat Incorporated
• Inventors: Miller, Mark J., Dankberg, Mark D.
• Granted Patent: US 8,208,864 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04B 7/18523 Satellite systems for providing broadcast service to terrestrial stations, i.e. broadcast satellite service arrangements specially adapted for satellite broadcast receiving H04H40/90; picture transmission via satellite H04N1/00103; television transmission via satellite H04N7/20
• CPC Class Codes: H04L 1/0005 applied to payload information
• CPC Class Codes: H04L 1/0011 applied to payload information
• CPC Class Codes: H04L 5/0005 Time-frequency
• CPC Class Codes: H04L 5/0016 Time-frequency-code
• CPC Class Codes: H04L 5/22 using time-division multiplexing
• CPC Class Codes: H04W 28/0236 radio quality, e.g. interference, losses or delay
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/242 taking into account path loss

Abstract

A system to provide narrowcast communications uses adaptive data rate control to individual subscribers such that the effects of precipitation or other link conditions, which are not common to all subscribers, is mitigated. The invention takes advantage of the fact that the narrowcast data consist of packets which are individually addressed to specific subscribers, or groups of subscribers. The narrowcast data is communicated on a plurality of channels, each of potentially differing data rates. The subscribers are assigned a particular channel, based upon their link quality, to receive packets addressed to them. The lower data rate channel will be less affected by adverse link conditions and are hence assigned to subscribers most likely to incur adverse link conditions.

Claims

1. In a narrowcast satellite communication network having a hub station transmitting to a satellite repeater and a plurality of receiving subscriber terminals, a method comprising:

transmitting data from said hub station addressed to selected ones of said receiving subscriber terminals to said satellite repeater on a selection of channels;

receiving and relaying at said satellite repeater, said data on said selection of channels to a selected subset of said receiving subscriber terminals using less than all available signal channels;

at each receiving subscriber terminal, determining signal quality metrics on the basis of qualities of said signal channels received from said satellite repeater and addressed to said receiving subscriber terminal;

communicating said signal quality metrics determined at said receiving subscriber terminals to said hub station;

at said hub station, grouping pluralities of said receiving subscriber terminals into subgroups according to said signal quality metrics;

varying at least one of a frequency bandwidth, a power level, a coding scheme, a modulation scheme and a data rate to produce a plurality of redefined channels;

signaling said subgroups to use at least one of said redefined channels for subsequent reception of said data; and

narrowcasting from said hub station said subsequent data to said subgroups of receiving subscriber terminal using said at least one of said redefined channels via said satellite repeater.