Turbo equalization for EDGE system with DDF-SOVA

Author

Tang, Xiang-Guo ; Ding, Zhi

Author_Institution

Dept. of Electr. & Comput. Eng., California Univ., Davis, CA, USA

Volume

1

fYear

2001

fDate

4-7 Nov. 2001

Firstpage

295

Abstract

As one of the 3G wireless communication standards, EDGE (enhanced data rates for global evolution) adopts 8PSK modulation to provide higher data rates using the existing TDMA system infrastructure of GSM. We study a receiver scheme which improves the detection performance through iterative equalization and decoding. Due to the 8-ary 8PSK alphabet of EDGE modulation, the number of states in a trellis for a full turbo equalizer is prohibitively high. Hence, a delayed decision feedback (DDF) approach is used to reduce the number of trellis states. A non-binary soft output Viterbi algorithm (SOVA) is developed to calculate the soft value of 8PSK channel input symbols. Iterative channel estimation is also applied to improve the accuracy of channel estimation. In addition, a prefilter is designed to "shorten" the ISI (intersymbol interference) channel length. Simulation results show our turbo equalization approach can achieve about 2 dB BER (FER) performance gain compared with non-turbo detection after 5 detection iterations.

Keywords

Rayleigh channels; Viterbi decoding; cellular radio; decision feedback equalisers; error statistics; intersymbol interference; iterative decoding; minimum shift keying; parameter estimation; phase shift keying; radio receivers; time division multiple access; 3G wireless communication; BER; EDGE system; GMSK; GSM; ISI; PSK modulation; Rayleigh fading channel; TDMA; channel estimation; delayed decision feedback; intersymbol interference; iterative decoding; iterative equalization; iterative estimation; prefilter; receiver; soft output Viterbi algorithm; turbo equalization; Channel estimation; Communication standards; Delay; Equalizers; GSM; Intersymbol interference; Iterative decoding; State feedback; Time division multiple access; Wireless communication;

fLanguage

English

Publisher

ieee

Conference_Titel

Signals, Systems and Computers, 2001. Conference Record of the Thirty-Fifth Asilomar Conference on

Conference_Location

Pacific Grove, CA, USA

ISSN

1058-6393

Print_ISBN

0-7803-7147-X

Type

conf

DOI

10.1109/ACSSC.2001.986924

Filename

986924