Turbo Equalizer: A Solution to 4G Mobiles

Abstract

Turbo codes exhibit excellent performance gains. Turbo equalization is an iterative equalization and decoding technique. It can achieve equally impressive performance gains for communication systems. Turbo codes are send digital data over channels that require equalization, i.e. those which suffer from inter-symbol interference (ISI). Turbo equalizers have been shown to be successful in mitigating the effects of inter-symbol interference introduced by partial response modems and by dispersive channels for code rates of R>1/2. The performance of iterative equalization and decoding (IED) using an M-BCJR equalizer is analyzed. Bit error rate (BER), frame error rate simulations and extrinsic information transfer (EXIT) charts are used to study and compare the performances BCJR equalizers on precoded and non-precoded channels. We predict the BER performance of Turbo equalizer using the M-BCJR equalizer from EXIT charts and explain the discrepancy between the observed and predicted performances.