The design and performance investigation of turbo-equalization structure with 8-PSK modulation for ISI-channels

The turbo-equalization concept was firstly introduced by Douillard et al. (1995). They used an iterative principle for equalization of a convolutional coded signal transmitted through interfered (ISI) channels. Then, Raphaeli and Zarai (1997) applied the turbo-equalization principle to turbo codes and provided 1dB increment in gain of the system according to classical equalization structures. On the other hand, it is possible to improve the performance of the 8-PSK modulation technique which is preferred in bandwidth limited channels by using soft-input soft-output modules in both equalizer and decoder. By taking into consideration the above idea, in this study, for an 8-PSK modulated turbo coded signal a turbo-equalizer is designed and the performance of the system is investigated using a simulation technique.