On Optimal Stepsize for Soft Decision Viterbi Decoding

Eui-Cheol LIM  Hyung-Jin CHOI 

Publication
IEICE TRANSACTIONS on Communications  Vol.E88-B  No.12  pp.4651-4654
Publication Date: 2005/12/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Fundamental Theories for Communications
Keyword: 
soft decision,  quantization,  stepsize, 

Full Text: PDF(284.3KB)

Summary: 
This letter presents a method of finding the optimal quantization stepsize that minimizes quantization loss and maximizes coded BER performance. We define 'Information Error Rate'(IER) and obtain the equation of the modified constraint length (Km) to obtain an upper bound of coded BER performance of a l bit quantized soft decision Viterbi decoder. Using IER and Km, we determine the optimal quantization stepsize of a 2 bit and 3 bit quantized soft decision decoding system in an AWGN channl with respect to SNR, and verify our strategies by simulation results.