Development of blind turbo equalization algorithms in the communication systems

In this study, blind turbo equalization problem for single-input single-output and multiple-input multiple-output communication systems is investigated. Three different blind turbo equalizers (receiver) are developed for both DPSK and MSK modulation in the SISO communication systems. Developed blind receivers use soft channel estimation. Using of the soft information that comes from the channel decoder provides more correct channel estimation. Communication channels are modelled as discrete-time FIR filter and its coefficients are estimated with EM, LMS and RLS algorithms in this study. Developed blind turbo equalization algorithms for SISO systems are adapted to MIMO communication systems. This adaptation produces two semi blind turbo equalizers for MIMO systems. Firstly, blind turbo equalization algorithms are derived mathematically and then computer programming are done according to these algorithms. Developed blind receivers are compared with each other in terms of bit error rate performances via computer simulations. In addition, bit error rate curves of turbo equalization (channel parameters are perfectly known) for both SISO and MIMO systems are plotted. BER performances of developed blind turbo equalizers are very promising