Teledesic LLC

Karl R Griep

Sami M Hinedi

Samson Million

Mark Alan Sturza

Farzad Ghazvinian

A data communication system for a constellation of satellites (,, 13,, . . . ) 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 (,). Each data packet includes a header (,) with control information and a payload (,) of data to be communicated. The information contained in the header is used to route the data packets through the satellite constellation to the appropriate intended satellite or to a downlink satellite (,). The header and payload databits are outer forward error correction (FEC) encoded (,), optionally interleaved separately (,), and inner error correction encoded by inner FEC encoders (,). After receipt by an uplink satellite (,), processing of the header is accomplished to recover the header of the original signal. That information may then be used to identify and separate the payload into payload intended for the receiving satellite and payload not intended for the receiving satellite. If receiving satellite payload codewords are identified, the corresponding data is processed and used by the satellite. In one embodiment, a hard decision (,) is applied to the payload data packets that are not intended for use by the receiving satellite. In another embodiment, a hard decision is applied to all payload data. The information contained in the header is then used to route the data packets through the satellite constellation to the appropriate intended satellite or to a downlink satellite (,).

System and method of separately coding the header and payload of a data packet for use in satellite data communication

A serial concatenated convolutional coding system for a constellation of low-Earth-orbit (LEO) satellites for transmitting input data bits of information is disclosed. The input data bits are systematically outer convolutional encoded (,), producing outer encoded data bits and outer encoded parity bits. Some of the bits of the outer encoded parity bits are remove by a puncturer (,), and the remaining outer encoded parity bits and the outer encoded data bits are bit interleaved (,). The bit interleaved, outer encoded data and remaining parity bits are systematically inner convolutional encoded (,) producing concatenated coded, bit interleaved inner data bits and concatenated coded, bit interleaved inner parity bits. Some of the bits of the concatenated coded, bit interleaved inner parity bits are removed by a puncturer (,), and the remaining concatenated coded, bit interleaved inner parity bits and the concatenated coded, bit interleaved inner data bits are combined (,). Upon receipt by a serial concatenated convolutional decoding system (,), the serially concatenated convolutional coded data and parity bits are iteratively decoded to recover the data bits of information of the original signal. During decoding erasures are inserted (,) for the parity bits removed by puncturing. Decoding is accomplished by soft input, soft output (SISO) modules (,).

Punctured serial concatenated convolutional coding system and method for low-earth-orbit satellite data communication

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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Seattle, WA, United States of America

Karl R Griep