Remedying low densities of ONEs in transmission and reception of digital television signals

A method for transmitting successive shortened Bose-Chaudhuri-Hocquenghem (BCH) codewords utilized by a digital television transmitter, said method comprising the steps of:

• counting the number of ONEs in each one of said successive shortened BCH codewords;
• complementing the bits of each of said successive shortened BCH codewords having fewer than a prescribed number of ONEs therein, which fewer number is determined by a previous one of said counting steps;
• forward-error-correction coding the bits of said bye-interleaved succession of shortened BCH codewords to generate a digital modulating signal;
• and
• modulating a carrier wave of electromagnetic energy in accordance with said digital modulating signal.

A method for decoding concatenated coding of data bits in electronic apparatus, said concatenated coding having been generated by further coding of a collection of shortened Bose-Chaudhuri-Hocquenghem (BCH) codewords, some of which shortened BCH codewords are TRUE in form and some of which are FALSE in form, said method comprising steps of:

• decoding said further coding of said collection of shortened BCH codewords;
• using a ZEROs-fill technique to lengthen each of said shortened BCH codewords recovered by said step of decoding said further coding, thus to generate a first collection of possibly TRUE full-length BCH codewords;
• attempting to decode each of said first collection of possibly TRUE full-length BCH codewords, to generate a first set of respective decoding results together with respective indications as to whether each of said first set of respective decoding results is correct;
• ONEs' complementing the bits of said shortened BCH codewords recovered by said step of decoding said further coding;
• using a ZEROs-fill technique to lengthen each of said shortened BCH codewords having had its bits ONEs' complemented, thus to generate a second collection of possibly TRUE full-length BCH codewords;
• attempting to decode each of said second collection of possibly TRUE full-length BCH codewords, to generate a second set of respective decoding results together with respective indications as to whether each of said second set of respective decoding results is correct;
• and
• generating a third set of decoding results comprising those of said first set of respective decoding results indicated to be correct and those of said second set of respective decoding results indicated to be correct.

Receiver apparatus for digital television signals that transmit via a carrier wave of electromagnetic energy successive shortened Reed-Solomon (RS) codewords encoding respective data packets, selected ones of which shortened RS codewords have had their bits ONEs' complemented, said receiver apparatus comprising:

• a tuner for converting a selected carrier wave of electromagnetic energy modulated in accordance with a digital television signal to a baseband digital television signal;
• a decoder for decoding forward-error-correction coding of bits of said baseband digital television signal, thus to recover byte-interleaved shortened RS codewords, selected ones of which shortened RS codewords were transmitted after having had their bits ONEs' complemented;
• a byte de-interleaver for de-interleaving said byte-interleaved shortened RS codewords, thus to recover successive shortened RS codewords, selected ones of which were transmitted after having had their bits ONEs' complemented;
• RS decoding apparatus for determining whether each of said successive shortened RS codewords was transmitted after said having had its bits ONEs' complemented, attempting to decode each of said successive shortened RS codewords to reproduce with possible corrections of any erroneous bytes therein a respective lateral-data packet coded within each of said successive shortened RS codewords whether or not that said successive shortened RS codeword had the bits thereof ONEs' complemented before its transmission, and determining which ones of said respective lateral-data packets as so reproduced are correct for being free of any detectable byte errors in bytes thereof;
• and
• further receiving apparatus for utilizing ones of said lateral-data packets as so reproduced by said RS decoding apparatus, including at least those that are determined to be correct.

Receiver apparatus for digital television signals transmitting via a carrier wave of electromagnetic energy successive shortened Reed-Solomon (RS) codewords encoding respective data packets, selected ones of which shortened RS codewords have had their bits ONEs' complemented, said receiver apparatus comprising:

• a tuner for converting a selected carrier wave of electromagnetic energy modulated in accordance with a digital television signal to a baseband digital television signal;
• a decoder for decoding forward-error-correction coding of bits of said baseband digital television signal, thus to recover byte-interleaved shortened RS codewords, selected ones of which shortened RS codewords were transmitted after having had their bits ONEs' complemented;
• a byte de-interleaver for de-interleaving said byte-interleaved shortened RS codewords, thus to recover successive shortened RS codewords, selected ones of which were transmitted after having had their bits ONEs' complemented;
• exclusive-ORing apparatus for exclusive ORing the hard data bit of each soft-decision from said byte de-interleaver response with the bits expressing the level of confidence in that hard data bit, thus to generate bits expressive of an absolute value of the level of lack-of-confidence in that hard data bit;
• apparatus for selecting the largest absolute value of the level of lack-of-confidence in the eight hard data bits of each byte of said of successive shortened RS codewords to be ascribed to that byte as the absolute value of the level of lack-of-confidence in that byte;
• RS decoding apparatus for determining whether each of said successive shortened RS codewords was transmitted after said having had its bits ONEs' complemented, attempting to decode each of said successive shortened RS codewords to reproduce it with possible corrections of any erroneous bytes therein as a respective one of a succession of lateral RS decoding results whether or not that said successive shortened RS codeword had the bits thereof ONEs' complemented before its transmission, and determining whether or not each said lateral RS decoding result is correct for being free of any detectable byte errors in bytes thereof;
• an extended-byte-organized memory for temporarily storing bytes of 255 successive ones of said shortened RS codewords supplied as respective ones of said lateral RS decoding results from said RS decoding apparatus together with respective byte extensions descriptive of the absolute values of the levels of lack-of-confidence in the byte that is extended, the byte extensions for bytes of each said shortened RS codeword reproduced by said RS decoding apparatus that is determined to be correct having the lowest possible level of lack-of-confidence therein ascribed to them, the byte extensions for bytes of each said shortened RS codeword reproduced by said RS decoding apparatus that is determined not to be correct having ascribed to them respective levels of lack-of-confidence from said apparatus for selecting the largest absolute value of the level of lack-of-confidence in the eight hard data bits of each byte of said successive shortened RS codewords to be ascribed to that byte as the absolute value of the level of lack-of-confidence in that byte, said extended-byte-organized memory operable for having the extended bytes of said successive shortened RS codewords reproduced by said RS decoding apparatus written to successive rows of extended-byte storage locations therein for temporary storage, said extended-byte-organized memory further operable for having the extended bytes of full-length Reed-Solomon codewords read from or written to respective columns of extended-byte storage locations therein, said extended-byte-organized memory also further operable for having the extended bytes of shortened Reed-Solomon codewords read from or written to respective columns of extended-byte storage locations therein;
• a TRS decoder for full-length Reed-Solomon codewords read from respective columns of extended-byte storage locations in said extended-byte-organized memory, said TRS decoder operable for attempting to decode each of said full-length RS codewords not known to be free from discernible byte error to correct every discernible byte error therein, each of said full-length RS codewords having its bytes most probable to be in error located for said TRS decoder depending on absolute values of the levels of lack-of-confidence in them as expressed in their respective extensions, said TRS decoder connected for updating the extended bytes of each full-length RS codeword that it corrects by over-writing the former extended bytes thereof temporarily stored in one of said columns of extended-byte storage locations in said extended-byte-organized memory, in which said updating the byte extensions for bytes of each said full-length RS codeword that said TRS decoder corrects have the lowest possible level of lack-of-confidence therein ascribed to them;
• an RS decoder for shortened Reed-Solomon codewords read from respective rows of extended-byte storage locations in said extended-byte-organized memory, said RS decoder operable for attempting to decode each of said shortened RS codewords not known to be free from discernible byte error to correct every discernible byte error therein, each of said shortened RS codewords having its bytes most probable to be in error located for said RS decoder depending on absolute values of the levels of lack-of-confidence in them as expressed in their respective extensions, said RS decoder connected for updating the extended bytes of each shortened RS codeword that it corrects by over-writing the former extended bytes thereof temporarily stored in one of said rows of extended-byte storage locations in said extended-byte-organized memory, in which said updating the byte extensions for bytes of each said shortened RS codeword that said RS decoder corrects have the lowest possible level of lack-of-confidence therein ascribed to them;
• an IPE packet selector for selectively reproducing respective IPE packets from shortened RS codewords read from said extended-byte-organized memory after TRS-decoding and RS-decoding procedures concerning them have been completed;
• and
• apparatus for utilizing ones of said lateral-data packets selectively reproduced by said IPE packet selector.

Receiver apparatus for digital television signals that transmit via a carrier wave of electromagnetic energy successive shortened Bose-Chaudhuri-Hocquenghem (BCH) codewords encoding respective data packets, selected ones of which shortened BCH codewords have had their bits ONEs' complemented, said receiver apparatus comprising:

• a tuner for converting a selected carrier wave of electromagnetic energy modulated in accordance with a digital television signal to a baseband digital television signal;
• a decoder to decode forward-error-correction (FEC) coding of bits of said baseband digital television signal, thus to recover shortened BCH codewords, selected ones of which shortened BCH codewords were transmitted after having had their bits ONEs' complemented;
• BCH decoding apparatus for determining whether each of said successive shortened BCH codewords was transmitted after said having had its bits ONEs' complemented, attempting to decode each of said successive shortened BCH codewords to reproduce with possible corrections of any erroneous bytes therein a respective lateral-data packet coded within each of said successive shortened BCH codewords whether or not that said successive shortened BCH codeword had the bits thereof ONEs' complemented before its transmission, and determining which ones of said respective lateral-data packets as so reproduced are correct for being free of any detectable byte errors in bytes thereof;
• and
• further receiving apparatus for utilizing ones of said lateral-data packets as so reproduced by said BCH decoding apparatus, including at least those that are determined to be correct.