Turbo Equalization for an 8-PSK Modulation Scheme in a Mobile TDMA Communication System

Turbo equalization iteratively detects coded data over a frequency selective channel. An 8-PSK modulation scheme gives rise to a high number of states in a trellis based equalizer. In this abstract we show how a linear MMSE decision feedback equalizer can incorporate a priori information from the channel decoder. This technique enables the equalizer to make less erroneous decisions and provides better soft values to the channel decoder. The simulation environment is based on the GSM system. First simulation results indicate that the coded BER can be improved by about 2dB using 2 iterations.