Digital communication system having improved pilot encoding
First Claim
1. A digital time division multiple access communication system comprising:
- a time slot comprising four quadrature amplitude modulation sub-channels of pre-selected time duration;
a plurality of sync, pilot and data symbols in respective sync, pilot and data symbol positions of each sub-channel, with the pilot symbols arranged in a pre-selected pilot symbol format;
said data symbols modulated according to a pre-selected order of modulation; and
a plurality of dual purpose symbols in respective pilot symbol positions of said pilot symbol format and modulated with an order of modulation less than that of said data symbols.
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Accused Products
Abstract
A time division multiple access communication system is provided having multiple sub-channels according to known quadrature amplitude modulation techniques. Each sub-channel has a pre-determined time duration and is divided by a pre-determined number of symbol position time divisions. The symbol positions carry color codes and ACP codes in addition to sync, pilot and data symbols. Pilot symbols in the second half of the slot are replaced with dual purpose color code and ACP symbols. The dual purpose symbols are either modulated with a lower order modulation than data symbols or are repeated values of dedicated symbols located earlier in the same slot, or both. Slot throughput is attained with a minimal bit error rate penalty.
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Citations
36 Claims
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1. A digital time division multiple access communication system comprising:
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a time slot comprising four quadrature amplitude modulation sub-channels of pre-selected time duration;
a plurality of sync, pilot and data symbols in respective sync, pilot and data symbol positions of each sub-channel, with the pilot symbols arranged in a pre-selected pilot symbol format;
said data symbols modulated according to a pre-selected order of modulation; and
a plurality of dual purpose symbols in respective pilot symbol positions of said pilot symbol format and modulated with an order of modulation less than that of said data symbols. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A digital time division multiple access communication system comprising:
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a time slot comprising four quadrature amplitude modulation sub-channels of pre-selected time duration;
a plurality of color code, ACP, sync, pilot and data symbols in respective color code, ACP, sync, pilot and data symbol positions of each sub-channel, with the pilot symbols arranged in a pre-selected pilot symbol format; and
a plurality of dual purpose symbols in respective pilot symbol positions of said pilot symbol format and comprising copies of at least one of said color code symbols and said ACP symbols. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A digital time division multiple access communication system comprising:
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a time slot comprising four quadrature amplitude modulation sub-channels of pre-selected time duration;
a plurality of sync, pilot and data symbols in respective sync, pilot and data symbol positions of each sub-channel, with the pilot symbols arranged in a pre-selected pilot symbol format;
said data symbols modulated according to a pre-selected order of modulation; and
a plurality of dual purpose symbols comprising copies of at least one of said color code symbols and said ACP symbols, located in respective pilot symbol positions of said pilot symbol format and modulated with an order of modulation less than that of said data symbols. - View Dependent Claims (14, 15, 16, 17, 18)
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19. A method of digital time division multiple access communication comprising the steps of:
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providing a time slot comprising four quadrature amplitude modulation sub-channels of pre-selected time duration;
providing a plurality of sync, pilot and data symbols in respective sync, pilot and data symbol positions in said time slot, with the pilot symbols arranged in a pre-selected pilot symbol format;
modulating said data symbols with a pre-selected order of modulation;
providing a derived pilot symbol, modulating said derived pilot symbol with an order of modulation less than that of said data symbols to produce a dual purpose symbol comprising one of said dual purpose color code symbol and said dual purpose ACP symbol and placing said dual purpose symbol in a pre-selected pilot symbol position of said pilot symbol format. - View Dependent Claims (20, 21, 22, 23, 24)
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25. A method of digital time division multiple access communication system comprising the steps of:
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providing a time slot comprising four quadrature amplitude modulation sub-channels of pre-selected time duration;
providing a plurality of color code, sync, pilot and data symbols in respective color code, sync, pilot and data symbol positions in said time slot, with the pilot symbols arranged in a pre-selected pilot symbol format; and
copying at least one of said color code symbols and said ACP symbols to provide a dual purpose symbol and placing said dual purpose symbol in a pre-selected pilot symbol position of said pilot symbol format. - View Dependent Claims (26, 27, 28, 29, 30)
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31. A method of digital time division multiple access communication system comprising the steps of:
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providing a time slot comprising four quadrature amplitude modulation sub-channels of pre-selected time duration;
providing a plurality of color code, sync, pilot and data symbols in respective color code, sync, pilot and data symbol positions in said time slot, with the pilot symbols arranged in a pre-selected pilot symbol format;
modulating said data symbols with a pre-selected order of modulation; and
copying at least one of said color code symbols and said ACP symbols to produce a derived pilot symbol, modulating said derived pilot symbol with an order of modulation less than that of said data symbols to produce a dual purpose symbol and placing said dual purpose symbol in a pre-selected pilot symbol position of said pilot symbol format. - View Dependent Claims (32, 33, 34, 35, 36)
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Specification