Butterfly structure in trellis-coded modulation

Author

Dill, Jeffrey C. ; Lo, Yung-C ; Lindsey, Alan R.

Author_Institution

Dept. of Electr. Eng. & Comput. Sci., Ohio Univ., Athens, OH, USA

fYear

1999

fDate

6/21/1905 12:00:00 AM

Firstpage

707

Abstract

Trellis coded modulation was designed to improve error performance of synchronous data links without sacrificing data rate, or expanding bandwidth. The codes are interpreted as binary convolutional codes with a mapping of coded bits into multilevel/phase signals to increase free Euclidean distance. The technique referred to as “mapping by set partitioning” is claimed as an optimal assignment. The rules for assigning channel signals first proposed by Ungerboeck assure maximum free Euclidean distance. However, by taking advantage of a butterfly structure in the trellis and modifying Ungerboeck´s rules, the multiplicity of error events with free Euclidean distance can be minimized. In this paper, the relationship between butterfly and signal assignment is revealed and a modified rule is proposed for optimality of the trellis assignment

Keywords

binary codes; convolutional codes; phase shift keying; trellis coded modulation; Ungerboeck signal partitioning; binary convolutional codes; butterfly structure; error events minimization; free Euclidean distance; mapping by set partitioning; multilevel/phase signals; optimal assignment; rate 2/3 TC-8PSK; signal assignment; trellis assignment; trellis-coded modulation; Amplitude modulation; Bandwidth; Computer science; Convolution; Convolutional codes; Euclidean distance; Lattices; Modulation coding; Signal mapping; System performance;

fLanguage

English

Publisher

ieee

Conference_Titel

Global Telecommunications Conference, 1999. GLOBECOM '99

Conference_Location

Rio de Janeireo

Print_ISBN

0-7803-5796-5

Type

conf

DOI

10.1109/GLOCOM.1999.830154

Filename

830154