Patent ID: 9143375
Filing Date: 2015-09-22
Classification: H04L,H04N

Abstract:
1. A method for preparing packets of digital data to be transmitted by a COFDM broadcast transmitter so as to facilitate iterative-diversity reception by COFDM broadcast receivers of suitable design, said method comprising steps of: forward-error-correction (FEC) coding successive frames of digital data to generate respective FEC codewords, each having the same prescribed number of bits; writing said FEC codewords to temporary storage locations within a digital memory to be temporarily stored therein for a number at least one of COFDM symbol intervals; twice reading said FEC codewords from said temporary storage locations within said digital memory, initially reading portions of FEC codewords in each of successive COFDM symbols in a first time-sequential order from said temporary storage locations, and finally reading said portions of said FEC codewords in each of successive COFDM symbols in a second time-sequential order from said temporary storage locations some time after their being initially read; mapping the bits of each portion of said FEC codeword initially read from said temporary storage locations to modulation symbol constellations to generate digital coordinates descriptive of successive ones of said modulation symbol constellations; mapping the bits of each said portion of said FEC codeword finally read from said temporary storage locations to modulation symbol constellations to generate digital coordinates descriptive of successive ones of said modulation symbol constellations, said mapping of said bits of each said FEC codeword finally read from said temporary storage locations to said modulation symbol constellations differing from said mapping of said bits of each said FEC codeword initially read from said temporary storage locations to said modulation symbol constellations, those bits of each said FEC codeword mapped less robustly to said modulation symbol constellations when initially read from said temporary storage locations being mapped more robustly to said modulation symbol constellations when finally read from said temporary storage locations, those bits of each said FEC codeword mapped more robustly to said modulation symbol constellations when initially read from said temporary storage locations being mapped less robustly to said modulation symbol constellations when finally read from said temporary storage locations; and generating a modulated carrier wave responsive to said digital coordinates descriptive of successive ones of said modulation symbol constellations mapping each said FEC codeword as twice read from said temporary storage locations within said digital memory, said modulated carrier wave to be transmitted by said broadcast transmitter.