Development of an LSI maximum-likelihood convolutional decoder for advanced forward error correction capability on the NASA 30/20 GHz program

A low-complexity, reduced-power Viterbi Algorithm

“…Since the first transform also has the same effect, neither transform is applied. However, changing the state-metric update sequence (this reorders decision bits in TRN) in ACS, retains the first transform's benefits: reduced traceback complexity and correctly ordered 8-bit output 6 at the cost of a bitreversal of the 6-bit state index before traceback (Example A8).…”

“…Many applications use rate 1/n convolutional codes and decode them using the Viterbi Algorithm (VA). Commonly used rate (n-1)/n punctured convolutional codes [1]- [6] are also decoded by the VA with minor change [7]. The VA also demodulates trellis coded and continuous phase modulations (with or without channel equalization, as in the Global System for Mobile communications (GSM)).…”

High‐Rate Punctured Convolutional Codes

“…Using the weight spectrum an upper bound on the bit error probability bound P^ of a code of rate R=b/V is given by PB < ^ ^_,CJPJ (15) b J=dfreé…”

“…Although one could select the punctured code on the basis of its free distance only, a finer method consists of determining the weight spectrum of the punctured code according to (13) and (14) and then plotting the bit error probability bound (15). The code yielding the best error performance may be thus selected as the best punctured code, provided it is not catastrophic.…”