Oguz Bayat

Adaptive and Iterative Transceiver Designs For Wireless Communication Applications

Date: Thursday, October 5, 2006

Abstract:

In the first phase of this research, efficient turbo code based digital transmission systems are proposed. Simulation results of the digital transmission systems are provided for Gaussian and fading channels. The structure of turbo codes are examined in details and the factors that affect the performance are analyzed over AWGN, Rician and Rayleigh channels.

Channel coding is frequently utilized in the communication systems to increase power efficiency at a cost of sacrificing bandwidth. In order to overcome the cost of the channel coding and increasing the power efficiency simultaneously, system level designs of chosen coded modulations are investigated and compared with the existing coded modulations schemes. To provide a fair comparison among the coded modulations, bandwidth and power efficient turbo trellis coded modulation is implemented and simulated under Gaussian and fading channels. An optimized multilevel turbo coded modulation scheme is introduced by using phase shift keying modulation. The optimization process is based on providing lower overall bit error rate performance while employing unequal error protection on signaling constellation and using same component code at each level. The simulation results for this scheme are presented and compared with the turbo trellis coded modulation scheme. The superiority of the proposed multilevel turbo code scheme is improved by concatenating with a bandwidth and power efficient continuous phase modulation technique called MLTC-CPFSK. The BER performance of this scheme is simulated and compared with the reference schemes in the literature.

After designing power and bandwidth efficient proposed digital transmission systems, in the second phase of the research, these systems are applied to the channels with inter-symbol interference (ISI) added to AWGN. In order to deploy these channel coding applications over ISI channels, we integrate the equalization schemes into our proposed systems because turbo codes or coded modulations can not provide sufficient bit error rate itself over these channels. Finally, we offer the most suitable low complex equalization design, called DDFE, for both turbo coding and proposed schemes. The joint proposed channel coding and equalization models are called MLTEQ and MLTEQ-CPFSK. The performance of entire digital transmission designs are revealed under Proakis A and Proakis B channel consideration.

Thesis Committee: Prof. Bahram Shafai (advisor)
Prof. Osman N. Ucan (co-advisor)
Prof. Masoud Salehi
Prof. Hanoch Lev-Ari