Multi-channel parallel/serial concatenated convolutional codes and trellis coded modulation encoder/decoder
First Claim
1. A modem for communicating over a network having channels, comprising:
- a multichannel modulator connected to generate respective symbols representing bits applied to said multichannel modulator on each of said channels;
a controller;
a turbo-encoder having first and second Recursive Systematic Convolutional encoders (RSC encoders) receiving data from an input data source and connected to apply to said multichannel modulator first parity bits from said first RSC encoder and second parity bits from said second RSC encoder under control of said controller;
said controller being programmed to measure respective transmission characteristics of said channels;
said controller being programmed to apply information bits and only a portion of said first and second parity bits to said multichannel modulator responsive to a result of a measuring of said respective transmission characteristics of said channels.
1 Assignment
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Accused Products
Abstract
A method and apparatus to transmit turbo-encoded data in a multitone channel assigns the original data and selected parity bits across multitone subchannels allowing transmission of an entire turbo-encoded block withing one or few symbol time frame. Parity bits are selected by a procedure using data derived by optimization using simulation of a single-channel system. The optimization determines, for a specified bit error rate, for each possible number of information bits per symbol, the code rate corresponding to the lowest signal-to-noise ratio. Alternatively, in the simulation non-identical integer values may be applied to the channels to approximate non-integer values of code rate and information bits-per-channel in the aggregate. The optimized data are used to determine an optimal code rate and SNR for each channel. In assigning the respective bits to the channels, the number of parity bits in each channel are shared.
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Citations
11 Claims
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1. A modem for communicating over a network having channels, comprising:
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a multichannel modulator connected to generate respective symbols representing bits applied to said multichannel modulator on each of said channels; a controller; a turbo-encoder having first and second Recursive Systematic Convolutional encoders (RSC encoders) receiving data from an input data source and connected to apply to said multichannel modulator first parity bits from said first RSC encoder and second parity bits from said second RSC encoder under control of said controller; said controller being programmed to measure respective transmission characteristics of said channels; said controller being programmed to apply information bits and only a portion of said first and second parity bits to said multichannel modulator responsive to a result of a measuring of said respective transmission characteristics of said channels. - View Dependent Claims (2, 3, 4, 5)
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6. A method for encoding data for transmission in a multichannel network, comprising the steps of:
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a. measuring a transmission characteristic of a first channel of said multichannel network; b. measuring a transmission characteristic of a second channel of said multichannel network; c. encoding an information data stream, wherein said encoding step includes encoding said information data stream to produce a first parity bit stream and interleaving said information data stream and encoding the result of said interleaving to produce a second parity bit stream, said total parity bit stream includes said first and second parity bit streams to generate a total parity bit stream; d. selecting a portion of said total parity bit stream for transmission in said first channel responsive to a result of said steps a and b. - View Dependent Claims (7, 10, 11)
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8. A modem for communicating over a network having channels, comprising:
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a multichannel modulator connected to generate a respective symbol representing bits applied to said multichannel modulator on each of said channels; a controller; a turbo-encoder having first and second Recursive Systematic Convolutional encoders (RSC encoders) receiving data from an input data source and connected to apply to said multichannel modulator first parity bits from said first RSC encoder and second parity bits from said second RSC encoder under control of said controller; said controller having a memory for storing measured respective transmission characteristics of said channels; said controller being programmed to apply said information bits and only a portion of said first and second parity bits to said multichannel modulator responsively to said measured said respective transmission characteristics of said channels.
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9. A modem for communicating over a network having channels, comprising:
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a uniform interleaver; a multichannel modulator connected to generate a respective symbol representing bits applied to said multichannel modulator on each of said channels; a controller; a turbo-encoder having first and second Recursive Systematic Convolutional encoders (RSC encoders) receiving data from an input data source and connected to apply to said multichannel modulator first parity bits from said first RSC encoder and second parity bits from said second RSC encoder under control of said controller; said controller being programmed to measure respective transmission characteristics of said channels; said controller being programmed to apply information bits to said uniform interleaver and selected ones of said first and second parity bits to said multichannel modulator, said selected ones being selected by said controller responsively to a result of a measuring of said respective transmission characteristics of said channels; said uniform interleaver being connected to apply information bits also being to said multichannel modulator after being interleaved by said uniform interleaver.
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Specification