Coding system and method for low-earth orbit satellite data communication
First Claim
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; and
an 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.
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Accused Products
Abstract
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).
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Citations
28 Claims
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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:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A data communication method for a communication network comprising a constellation of low-Earth orbit (LEO) satellites and a plurality of ground stations for transmitting data packets to and receiving data packets from said 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 method comprising:
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forward error correction (FEC) coding data packets to be transmitted by said ground terminals to one of said LEO satellites prior to transmission by;
(i) outer FEC encoding the header and payload databits of said data packets;
(ii) interleaving the symbols of the resulting header and payload codewords; and
(iii) inner FEC encoding said interleaved, outer encoded header and payload codewords to produce concatenated coded, interleaved data packets;transmitting said concatenated coded, interleaved data packets to one of said LEO satellites; receiving said concatenated coded, interleaved data packets at one of said LEO satellites; FEC decoding said concatenated coded, interleaved data packets at said one of said LEO satellites by;
(i) inner decoding said concatenated coded, interleaved data packets to recover said interleaved, outer encoded header and payload codewords;
(ii) de-interleaving the symbols of said interleaved, outer encoded header and payload codewords to recover said outer encoded header codewords and said outer encoded payload codewords; and
(iii) outer decoding said outer encoded header codewords, but not said outer encoded payload codewords, to recover said header databits;conveying said header databits and said outer encoded payload codewords through said constellation of LEO satellites to another of said LEO satellites; FEC coding said header databits and said outer encoded payload codewords at said other satellite by;
(i) re-outer encoding said header databits;
(ii) interleaving the symbols of the resulting re-outer encoded header codewords and the symbols of said outer encoded payload codewords; and
(iii) inner encoding said interleaved, re-outer encoded header and said outer encoded payload codewords to produce re-concatenated coded, interleaved data packets;transmitting said re-concatenated coded, interleaved data packets to a ground terminal; receiving said re-concatenated coded, interleaved data packets at a ground terminal; and FEC decoding said re-concatenated coded, interleaved data packets at said ground terminal by;
(i) inner decoding said re-concatenated coded, interleaved data packets to recover said interleaved, re-outer encoded header and outer encoded payload codewords;
(ii) de-interleaving the symbols of said interleaved outer re-encoded header and outer encoded payload codewords to recover said re-outer encoded header databits and said outer encoded payload codewords;
(iii) outer decoding said re-outer encoded header codewords; and
(iv) outer decoding said outer encoded payload codewords. - View Dependent Claims (13, 14)
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15. In a data communication system wherein data packets that include header databits and payload databits are transmitted from a transmitting terminal to a receiving terminal via a plurality of satellites, the improvement comprising:
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an interleaver located at said transmitting terminal for interleaving the header databits with the payload databits; and a de-interleaver located at said receiving terminal for de-interleaving said interleaved header and payload databits. - View Dependent Claims (16, 17, 18)
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- 19. In a method of data communication wherein data packets that include header databits and payload databits are transmitted from a transmitting terminal to a receiving terminal via a plurality of satellites, the improvement comprising interleaving the header databits with the payload databits at the transmitting terminal and de-interleaving said interleaved header and payload databits at the receiving terminal.
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23. In a data communication system wherein data packets formed of header and payload databits that have been concatenated coded using inner and outer forward error correction (FEC) codes are transmitted from a transmitting terminal to a receiving terminal through a network of nodes by passing the data packets from node to node, the improvement comprising:
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an inner FEC decoder located at the node receiving data packets from said transmitting terminal for inner FEC decoding said concatenated coded data packets; an outer FEC decoder located at the node receiving data packets from said transmitting terminal for outer FEC decoding only said header databits, said payload databits remaining outer FEC encoded; an outer FEC encoder located at the node forwarding data packets to said receiving terminal for re-outer FEC encoding said header databits; and an inner FEC encoder located at said node forwarding data packets to said receiving terminal for inner FEC encoding said re-outer encoded header databits and said outer encoded payload databits. - View Dependent Claims (24, 25)
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26. In a method of data communication wherein data packets formed of header and payload databits that have been concatenated coded using inner and outer forward error correction (FEC) codes are transmitted from a transmitting terminal to a receiving terminal through a network of nodes by passing the data packets from node to node, the improvement comprising:
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inner FEC decoding said concatenated coded data packets at the node receiving data packets from said transmitting terminal; outer FEC decoding only said header databits at said node receiving data packets from said transmitting terminal; re-outer FEC encoding said header databits at said node forwarding data packets to said receiving terminal; and re-inner encoding said re-outer encoded header databits and said outer encoded payload databits at said node forwarding said data packets to said receiving terminal. - View Dependent Claims (27, 28)
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Specification