Citation

Abstract

This article compares the performance of binary turbo codes and Reed-Solomon (RS) codes in an optical communications system employing high-order pulseposition modulation (PPM) and an avalanche photodiode (APD) detector. Despite restriction of the turbo codes to binary alphabets and very simple 4- or 8-state encoders, they have coding gains 0.5-dB to 0.7-dB higher than equivalent-rate RS codes when using 256-PPM, employing a typical APD detector, and operating at an end-to-end bit-error rate (BER) of 10^-5. BER curves are given for code rates of 1/3 and 1/2, using a variety of turbo and RS coding methods. The simulations use an accurate modeling of APD output statistics instead of typical but less accurate Poisson or Gaussian approximations.

Keywords

turbo codes PPM optical channel optical communications coding theory channel coding

Details

Volume
42-138
Published
August 15, 1999
Pages
1–15
File Size
721.6 KB