Patent ID: 7031408
Filing Date: 2006-04-18
Classification: H03M,H04L

Abstract:
1. A method of conducting data communications between a transmitter site and a receiver site, comprising the steps of: at said transmitter site, (a) encoding data to be transmitted using an encoding modulation mechanism to produce an encoded data stream, and (b) transmitting said encoded data stream over a communication channel to said receiver site; and at said receiver site, (c) receiving said encoded data stream from said communication channel, (d) subjecting said encoded data stream to a first decoding mechanism to recover said data, as long as said first decoding mechanism remains in synchronization, (e) in response to said first decoding mechanism failing to remain in synchronization, subjecting said encoded data stream to a second decoding mechanism to derive a quasi-recovered data stream, and (f) in response to said second decoding mechanism recovering synchronization using said quasi-recovered data stream, adjusting properties of said first decoding mechanism in accordance with said second decoding mechanism, and subjecting said encoded data stream to said first decoding mechanism as adjusted in accordance with said second decoding mechanism, to thereby recover said data, wherein step (a) comprises encoding data to be transmitted using a self-concatenated convolutional code that is either decodable by a sequential decoder as said first decoding mechanism in step (d), or is decodable by a Viterbi decoder in said second decoding mechanism, to derive said quasi-recovered data stream for path recovery in step (e), and wherein step (f) comprises coupling estimated outputs from said Viterbi decoder to a syndrome former, which estimates a recovered sequential decoding state and generates an estimate of the validity of the recovered state, summing a prescribed number of consecutive syndrome former outputs and, in response to the sum of said consecutive syndrome former outputs being zero, adjusting properties of said first decoding mechanism in accordance with the contents of said syndrome former.