In wireless channels, the signal quality degrades mainly due to the additive noise and the random variation of attenuation of the signal, known as fading. The additive noise can be compensated to some extent using forward error correction (FEC) coding and automatic repeat request (ARQ). The fading can be compensated not First and foremost, I want to thank my co-supervisors Professor Halim Yanikomeroglu and Professor Ian Marsland. I am thankful to Professor Yanikomeroglu for the encouragement and the endless support throughout my Ph.D. studies. His advice on both research as well as on my career have been invaluable. I would also like to appreciate Professor Marsland for the enormous contribution of time and ideas to increase the productivity of my thesis. During my studies, we had numerous meetings and discussions on a variety of research issues; throughout them, he has taught me many aspects of communication systems. Completing my Ph.D. would have been difficult without his excellent support and patience. I would also like to thank my committee members and in particular my external examiner, Prof. Jean-Yves Chouinard, for their invaluable comments and feedback about many aspects of my thesis. I would like to acknowledge Huawei Technologies Canada Co., Ltd., the Ontario Ministry of Economic Development and Innovations Ontario Research Fund-Research Excellence (ORF-RE) program, and the Natural Sciences and Engineering Research Council of Canada's (NSERC) Strategic Partnership Grants for Projects (SPG-P) program for the financial support of this work. I am grateful to Huawei technologies for filing one patent application from my researches. I especially would like to thank Dr. Ngoc Dao and Dr. Gamini Senarath (Huawei Canada Co., Ltd.) for their invaluable comments and discussions.

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Typically, forward error correction (FEC) codes are designed based on the minimization of the error rate for a given code rate. However, for applications that incorporate hybrid automatic repeat request (HARQ) protocol and adaptive modulation and coding, the throughput is a more important performance metric than the error rate. Polar codes, a new class of FEC codes with simple rate matching, can be optimized efficiently for maximization of the throughput. In this paper, we aim to design HARQ schemes using multilevel polar codedmodulation (MLPCM). Thus, we first develop a method to determine a set-partitioning based bit-to-symbol mapping for high order QAM constellations. We simplify the LLR estimation of set-partitioned QAM constellations for a multistage decoder, and we introduce a set of algorithms to design throughputmaximizing MLPCM for the successive cancellation decoding (SCD). These codes are specifically useful for non-combining (NC) and Chase-combining (CC) HARQ protocols. Furthermore, since optimized codes for SCD are not optimal for SC list decoders (SCLD), we propose a rate matching algorithm to find the best rate for SCLD while using the polar codes optimized for SCD. The resulting codes provide throughput close to the capacity with low decoding complexity when used with NC or CC HARQ.

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Slow fading broadcast channels can model a wide range of applications in wireless networks. Due to delay requirements and the unavailability of the channel state information at the transmitter (CSIT), these channels for many applications are non-ergodic. The appropriate measure for designing signals in non-ergodic channels is the outage probability. In this paper, we provide a method to optimize STBCs based on the outage probability at moderate SNRs.Multilevel polar coded-modulation is a new class of coded-modulation techniques that benefits from low complexity decoders and simple rate matching. In this paper, we derive the outage optimality condition for multistage decoding and propose a rule for determining component code rates. We also derive an upper bound on the outage probability of STBCs for designing the set-partitioning-based labelling. Finally, due to the optimality of the outage-minimized STBCs for long codes, we introduce a novel method for the joint optimization of short-to-moderate length polar codes and STBCs.