초록 ▼

A data communication system for a constellation of low-Earth orbit (LEO) satellites (13a, 13b, . . . ) that employ Earth-fixed cellular beam management technology is disclosed. The data to be communicated is formed into data packets by a transmitting ground terminal (41). Each data packet includes a

A data communication system for a constellation of low-Earth orbit (LEO) satellites (13a, 13b, . . . ) that employ Earth-fixed cellular beam management technology is disclosed. The data to be communicated is formed into data packets by a transmitting ground terminal (41). Each data packet includes a header (41) and a payload (43). The header (41) contains address and other control information and the payload (43) contains the data to be communicated. The header and payload databits are separated (71) and outer forward error correction (FEC) encoded (72, 73) with an outer error correction code. The symbols of the outer encoded header and payload codewords are interleaved, first separately (74, 75) and then together (76). The outer encoded, interleaved header and payload codewords are inner encoded by an inner FEC encoder (77). Upon receipt by an uplink satellite (63), the inner error correction code is removed (87) and the resulting codeword symbols are de-interleaved (88, 89, 90). The outer error correction code of the header portion is then removed (91) to recover the header of the original signal. The information contained in the header is used to route the data packets through the satellite constellation to the appropriate downlink satellite (93). The downlink satellite re-outer encodes the header (95) and the symbols of the re-outer encoded header and the still outer encoded payload codewords are separately interleaved (96, 97) and then interleaved together (98). The interleaved re-outer encoded header and outer encoded payload databits are re-inner encoded (99). Upon receipt by a receiving ground terminal (107), the data packets are inner decoded (111) to remove the inner error correction code and the symbols of the header and payload codewords are de-interleaved (112, 113, 114). Then the header and payload codewords are outer decoded (115, 116) to remove the outer error correction codes and recover the header and payload. Preferably a payload filter (117) is included to eliminate the need to outer decode payload codewords not destined for the receiving ground terminal (107).

대표청구항 ▼

[ The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:] [1.] 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 receivin

[ The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:] [1.] 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.