Upper bounds on the free distance for trellis codes combined with CPFSK signals

Ertas T., Ali F.

ELECTRONICS LETTERS, vol.33, no.17, pp.1438-1440, 1997 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 33 Issue: 17
  • Publication Date: 1997
  • Doi Number: 10.1049/el:19970975
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.1438-1440
  • Bursa Uludag University Affiliated: No


It is well-known that CPM schemes themselves exhibit attractive spectral efficiencies and that combining them with a rate m/(m + 1) external trellis encoder with 2(m+1)-level modulation results in better power-bandwidth performance. Since the free distance is a good measure of performance, the authors construct upper bounds on the ultimately achievable Free distance for trellis codes of Ungerboeck type combined with constant-envelope CPFSK signals. Some encoders achieving the constructed upper bounds are also presented.