Patent ID: 9143785
Filing Date: 2015-09-22
Classification: H03M,H04L,H04N

Abstract:
1. A transmitter apparatus for generating coded orthogonal frequency-division multiplex (COFDM) transmissions in a digital television (DTV) system, said transmissions utilizable for conveying coding to be turbo decoded by DTV receivers in said DTV system, said transmitter apparatus comprising: a source of first bit-wise forward-error-correction (FEC) coding that is at least a component of said coding to be turbo decoded by said DTV receivers in said DTV system, said first bit-wise FEC coding composed of data bits and a first set of redundant parity bits, said coding to be turbo decoded by said DTV receivers including a second set of redundant parity bits in addition to said data bits and said first set of redundant parity bits; a first QAM symbol constellation mapper for mapping said first bit-wise FEC coding to a succession of complex samples descriptive of QAM symbol constellations, each of said QAM symbol constellations having a prescribed number of lattice points therein each having its own respective labeling, which prescribed number is the number two raised to a power that is a positive integer at least six, each said respective labeling composed of a number of bit-places equal to said power, said first QAM symbol constellation mapper operable for mapping said data bits of said first bit-wise FEC coding to bit-places within said labeling of said lattice points tending to have relatively low confidence levels of correctness associated therewith during de-mapping, said first QAM symbol constellation mapper further operable for mapping said first set of parity bits of said first bit-wise FEC coding to bit-places within said labeling of said lattice points tending to have confidence levels of correctness associated therewith during de-mapping at least as high as and in some cases higher than said data bits of said first bit-wise FEC coding tend to have; a first OFDM modulator for orthogonal frequency-division multiplexing complex samples of plural carrier waves in each of successive OFDM windows responsive to respective OFDM symbol blocks supplied thereto; a first parser of said complex samples descriptive of QAM symbols from said first QAM symbol constellation mapper into effective portions of successive ones of said OFDM symbol blocks supplied to said first OFDM modulator; a first pilot-carrier-insertion unit for completing said OFDM symbol blocks supplied to said first OFDM modulator, by inserting complex samples descriptive of unmodulated pilot carrier waves and of carrier waves modulated by Transmission Parameters Signaling (TPS); a first guard interval and cyclic prefix insertion unit for prefacing said complex symbols of said plural carrier waves in each of said successive OFDM windows employed by first OFDM modulator with complex symbols identical to those in a concluding portion of the same OFDM window, thereby to generate a respective one of a first succession of extended OFDM windows; and a digital-to-analog converter for converting said first succession of extended OFDM windows to an analog signal.