Statellite direct radio broadcast receiver for extracting a broadcast channel and service control header from time division multiplexed transmissions

• US 5,870,390 A
• Filed: 11/05/1996
• Issued: 02/09/1999
• Est. Priority Date: 11/05/1996
• Status: Expired due to Fees

• Current Assignee: Worldspace International Network Incorporated
• Original Assignee: Worldspace International Network Incorporated
• Inventors: Campanella, S. Joseph
• Primary Examiner(s): Kizou, Hassan
• Application Number:
  US08/746,067
• Time in Patent Office: 826 Days
• Field of Search: 370/316, 370/321, 370/322, 370/324, 370/325, 370/326, 370/468, 370/474, 370/312, 370/313, 370/537, 370/542, 370/522, 370/314, 455/3.2, 455/427, 455/12.1, 455/13.2
• US Class Current: 370/326
• CPC Class Codes: H04B 10/118 specially adapted for satellite communication
• 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: H04H 20/30 by a single channel
• CPC Class Codes: H04H 20/74 of satellite networks
• CPC Class Codes: H04H 40/90 specially adapted for satellite broadcast receiving
• CPC Class Codes: H04H 60/23 using cryptography, e.g. encryption, authentication, key distribution
• CPC Class Codes: H04J 3/04 Distributors combined with modulators or demodulators pulse distributors in general H03K5/15; pulse counters H03K21/00 - H03K29/06; for telegraphy H04L5/22, H04L13/00 - H04L23/00, H04L25/45; for telephony H04Q11/04
• CPC Class Codes: H04N 21/6143 involving transmission via a satellite

Abstract

A method of receiving one of a plurality of prime rate channels transmitted via downlink signals from a satellite comprises the step of demodulating downlink signals into a baseband time division multiplex bit stream comprising frames generated by the satellite. Each of the frames comprises a plurality of time slots, each of the time slots having a set of symbols. Each symbol in the set of symbols corresponding to a respective one of the prime rate channels occupies a similer symbol position in each of the time slots. The method further comprises the steps of locating the frames in the bit stream using a master frame preamble inserted therein by the satellite, and retrieving from the set of symbols in each of the time slots of at least one of the frames the symbols that correspond to one of the prime rate channels.

Claims

1. A method of receiving one of a plurality of broadcast channels transmitted via downlink signals comprising prime rate channels from a satellite comprising the steps of:

demodulating said downlink signals into a baseband time division multiplexed bit stream comprising frames generated by said satellite, each of said frames comprising a plurality of time slots, each of said time slots comprising a set of symbols, each symbol in said set of symbols corresponding to a respective one of said prime rate channels occupying a similar symbol position in each of said time slots;

locating said frames in said bit stream using a master frame preamble inserted in said bit stream by said satellite;

retrieving from said set of symbols in each of said time slots of at least one of said frames the symbols that correspond to at least one of said prime rate channels;

remultiplexing said symbols corresponding to said at least one of said prime rate channels to recover a broadcast channel corresponding thereto and as originally transmitted to said satellite; and

extracting a service control header from said broadcast channel.

2. A method as claimed in claim 1, wherein said retrieving step comprises the steps of:

locating a time slot control channel inserted in said bit stream by said satellite, said control channel indicating which of said time slots contain said symbols corresponding to each of said prime rate channels; and

extracting said symbols corresponding to one of said prime rate channels selected by a using said control channel.

3. The method as claimed in claim 1, further comprising the step of determining if said service control header comprises an identification code inserted in said broadcast channel by a broadcast station prior to transmission to said satellite for uniquely addressing a radio receiver.

4. The method as claimed in claim 1, further comprising the steps of:

determining if said service control header comprises control data; and

operating a radio receiver to perform at least one of a plurality of functions depending on said control data, said plurality of functions comprising operating said radio receiver in a selected reception mode to provide a selected multimedia service, to display data, to display an image, and to decrypt data using a decryption key provided in said service control header.

5. A radio receiver for receiving one of a plurality of prime rate channels transmitted via downlink signals from a satellite comprising:

a radio frequency device for receiving said downlink signals;

a channel recovery device for recovering said prime rate channels from said downlink signals by demodulating said downlink signals into a baseband time division multiplexed bit stream comprising frames generated by said satellite, each of said frames comprising a plurality of time slots, each of said time slots comprising a set of symbols, each symbol in said set of symbols corresponding to a respective one of said prime rate channels occupying a similar symbol position in each of said time slots, locating said frames in said bit stream using a master frame preamble inserted in said bit stream by said satellite, retrieving from said set of symbols in each of said time slots of at least one of said frames the symbols that correspond to at least one of said prime rate channels, remultiplexing said symbols corresponding to said at least one of said prime rate channels to recover a broadcast channel corresponding thereto and as originally transmitted to said satellite, and extracting a service control header from said broadcast channel; and

a controller, said controller being operable to receive said service control header from said channel recovery device and control said radio receiver to perform a plurality of functions comprising operating said radio receiver in a selected reception mode to provide a selected multimedia service, to display data, to display an image, to decrypt data using a decryption key provided in said service control header, and to respond to an identification code provided in said service control header to uniquely address said radio receiver.