Communication method and apparatus

• US 7,266,097 B2
• Filed: 10/02/2003
• Issued: 09/04/2007
• Est. Priority Date: 03/04/1998
• Status: Expired due to Term

• Current Assignee: Inmarsat Global Limited (Inmarsat PLC)
• Original Assignee: Inmarsat Global Limited (Inmarsat PLC)
• Inventors: Trachtman, Eyal, Feldman, Howard Ray, Wong, Hok Shuen, Wong, Siu Wah, Christodoulides, Louis Mimis
• Primary Examiner(s): Chan; Wing
• Assistant Examiner(s): Chu; Wutchung
• Application Number:
  US10/675,945
• Publication Number:
  US 20040114547A1
• Time in Patent Office: 1,433 Days
• Field of Search: 370/323, 370/322, 370/321, 370/326, 370/327, 370/468, 455/452.2, 455/12.1, 455/13.1, 455/430
• US Class Current: 370/323
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system
• CPC Class Codes: H04B 7/18532 Arrangements for managing transmission, i.e. for transporting data or a signalling message
• CPC Class Codes: H04L 1/0042 Encoding specially adapted to other signal generation operation, e.g. in order to reduce transmit distortions, jitter, or to improve signal shape H04L1/0067 takes precedence
• CPC Class Codes: H04L 1/0066 Parallel concatenated codes
• CPC Class Codes: H04L 1/0072 Error control for data other than payload data, e.g. control data
• CPC Class Codes: H04L 1/0078 Avoidance of errors by organising the transmitted data in a format specifically designed to deal with errors, e.g. location forward error control, e.g. FEC, CRC H04L1/004; adaptive formatting H04L1/0006; mappings H04L27/00
• CPC Class Codes: H04L 1/0083 Formatting with frames or packets; Protocol or part of protocol for error control
• CPC Class Codes: H04L 27/3466 by providing an alternative to one signal point
• CPC Class Codes: H04L 69/324 in the data link layer [OSI layer 2], e.g. HDLC
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04W 28/22 Negotiating communication rate
• CPC Class Codes: H04W 4/18 Information format or content conversion, e.g. adaptation by the network of the transmitted or received information for the purpose of wireless delivery to users or terminals
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 72/00 Local resource management
• CPC Class Codes: H04W 84/06 Airborne or Satellite Networks space-based or airborne stations H04B7/185

Abstract

A set of formats and protocols is proposed for a satellite communications system. In these formats, a pilot signal (PS) is inserted after every 25 or 29 data symbols. The formats consist of SCPC frames (F) which may contain either data (D) and in-band signaling information (SU), or only signaling information (SU). In either case, the contents of each frame (F) are error-correction coded before transmission with the same coding rate. Each data frame (F) carries the data content of an integral number of input user data frames (M), each of which comprises four subframes. Different symbol transmission rates are used for different input data rates, the symbol transmission rates being selected so that their different synchronizing clock rates can easily be obtained from a common clock. Data bursts may be preceded by a constant power level preamble (P). The formats and protocols satisfy the requirements of a high data rate satellite communications system.

Claims

1. A satellite communications system comprising a plurality of user terminals and at least one earth station, each of said user terminals being arranged to communicate with said at least one earth station via at least one satellite, wherein the system is arranged so that said user terminals and/or said earth station are able to receive data at any one of a set of input data rates and to transmit said user data at a corresponding one of a set of output data rates, wherein the ratio between one of said input data rates and the corresponding one of said output data rates differs from one of said input data rates to another one of said input data rates, such that the ratio between each of said input data rates and the lowest common multiple of said set of input data rates is less than the ratio between each of said output data rates and the lowest common multiple of said set of output data rates.

2. A system as claimed in claim 1, wherein said set of output data rates comprises 8, 16 and 33.6 ksymbol/s.

3. A system as claimed in claim 1, wherein said set of input data rates comprises 14.4, 28.8 and 64 kbit/s.

4. A system as claimed in claim 3, wherein said set of input data rates further includes 56 kbit/s.

5. Apparatus arranged to carry out the method of claim 1.