The augmented state diagram and its application to convolutional and turbo codes

  • Authors:

  • Ioannis Chatzigeorgiou;Miguel R. D. Rodrigues;Ian J. Wassell;Rolando A. Carrasco

  • Affiliations:

  • Computer Laboratory, University of Cambridge, Cambridge, United Kingdom;Instituto de Telecomunicações and the Department of Computer Science, University of Porto, Porto, Portugal;Computer Laboratory, University of Cambridge, Cambridge, United Kingdom;School of Electrical, Electronic and Computer Engineering, Newcastle University, Newcastle, United Kingdom

  • Venue:
  • IEEE Transactions on Communications
  • Year:
  • 2009

Quantified Score

Hi-index 0.00

Visualization

Abstract

Convolutional block codes, which are commonly used as constituent codes in turbo code configurations, accept a block of information bits as input rather than a continuous stream of bits. In this paper, we propose a technique for the calculation of the transfer function of convolutional block codes, both punctured and nonpunctured. The novelty of our approach lies in the augmentation of the conventional state diagram, which allows the enumeration of all codeword sequences of a convolutional block code. In the case of a turbo code, we can readily calculate an upper bound to its bit error rate performance if the transfer function of each constituent convolutional block code has been obtained. The bound gives an accurate estimate of the error floor of the turbo code and, consequently, our method provides a useful analytical tool for determining constituent codes or identifying puncturing patterns that improve the bit error rate performance of a turbo code, at high signal-to-noise ratios.