Patent ID: 6157642
Filing Date: 2000-12-05
Classification: H04B,H04L

Abstract:
A data communication system for a communication network comprising a constellation of low-Earth orbit (LEO) satellites and ground terminals for sending data packets to and receiving data packets from the low-Earth orbit satellites forming said constellation, said data packets including header databits and payload databits, said header databits including information regarding the destination of the payload databits, said data communication system comprising:a forward error correction (FEC) coding system located in said ground terminals for: (i) outer FEC encoding the header and payload databits of said data packets; (ii) interleaving the symbols of the resulting header and payload codewords; (iii) inner FEC encoding said interleaved, outer encoded header and payload codewords to produce concatenated coded, interleaved data packets; and (iv) transmitting said concatenated coded, interleaved data packets to one of said low-Earth orbit satellites;an FEC decoding system located in said low-Earth orbit satellites for: (i) receiving said concatenated coded, interleaved data packets; (ii) decoding said concatenated coded, interleaved data packets to recover said interleaved, outer encoded header and payload codewords; (iii) de-interleaving the symbols of said interleaved, outer encoded header and payload codewords; and (iv) outer decoding said header codewords, but not said payload codewords, to recover said header databits;an FEC coding system located in said low-Earth orbit satellites for: (i) receiving from other satellites data packets comprising header databits and outer encoded payload codewords; (ii) re-outer FEC encoding the header databits received from other satellites; (iii) interleaving the symbols of the resulting header codewords and said outer encoded payload codewords received from other satellites; (iv) re-inner FEC encoding said interleaved, re-outer encoded header and outer encoded payload codewords to produce re-concatenated coded, interleaved data packets; and (v) transmitting said re-concatenated coded, interleaved data packets to one of said ground terminals; andan FEC decoding system located in said ground terminals for: (i) receiving said re-concatenated coded, interleaved data packets; (ii) inner decoding said re-concatenated coded, interleaved data packets to recover said interleaved, re-outer encoded header and outer encoded payload codewords; (iii) de-interleaving said interleaved, re-outer encoded header and outer encoded payload codewords; and (iv) outer decoding said header and payload codewords to recover said header and payload databits.