MIMO communication systems: receiver design and diversity-multiplexing tradeoff analysis

After a few decades\u27 evolution of wireless communication systems, to ensure reliable high-speed communication over unreliable wireless channels is still one of the major challenges facing researchers and engineers. The use of multiple antennas at transmitter and receiver, known as multiple-input multiple-output (MIMO) communications, is one promising technology delivering desired wireless services. The main goal of this thesis is to study two important issues in wireless MIMO communication systems: receiver design for coded MIMO systems, and diversity-multiplexing tradeoff analysis in general fading channels;In the first part of this thesis, we decompose the receiver design problem into two sub-problems: MIMO channel estimation and MIMO detection. For the MIMO channel estimation, we develop an expectation-maximization (EM) based semi-blind channel and noise covariance matrix estimation algorithm for space-time coding systems under spatially correlated noise. By incorporating the proposed channel estimator into the iterative receiver structure, both the channel estimation and the error-control decoding are improved significantly. We also derive the modified Cramer-Rao bounds (MCRB) for the unknown parameters as the channel estimation performance metric, and demonstrate that the proposed channel estimation algorithm can achieve the MCRB after several iterations. For the MIMO detection, we propose a novel low-complexity MIMO detection algorithm, which has only cubic order computational complexity, but with near-optimal performance. For a 4x4 turbo-coded system, we show that the proposed detector had the same performance as the maximum a posteriori (MAP) detector for BPSK modulation, and 0.1 dB advantage over the approximated MAP detector (list sphere decoding algorithm) for 16-QAM modulation at BER = 10-4;In the second part of this thesis, we derive the optimal diversity-multiplexing tradeoff for general MIMO fading channels, which include different fading types as special cases. We show that for a MIMO system with long coherence time, the optimal diversity-multiplexing tradeoff is also a piecewise linear function, and only the first segment is affected by different fading types. We proved that under certain full-rank assumptions spatial correlation has no effect on the optimal tradeoff. We also argued that non-zero channel means in general are not beneficial for multiplexing-diversity tradeoff

The Organizational Change Dilemma Of ERP Implementation In A Small Manufacturing Company

ERP implementation in small and medium-sized businesses is especially challenging not only because of their shortage of budget and talents but also of the strong organizational and individual resistance to the overall organizational changes caused by the new technology.   This paper presents an original case of ERP implementation failure in a small manufacturing company and how we used the case to teach about organizational changes in a management class. Rather than leading a retrospective analysis of the case as many instructors would do with this type of change failure case study, we employed the four-step problem-solving case study approach to guide the students to identify the case problem, analyze its causes, prescribe and evaluate alternatives, and make a decision and develop detailed action plan to eventually solve the problem. Our purpose with such a thorough, quasi-experiential learning case study was to develop the students’ problem solving and decision making skills, particularly in understanding and leading organizational changes. Students received methodological, conceptual, practical, and technical learning benefits from the forward-looking, solution-focused case study of the small company’s ERP implementation failure

Navigating IEP Meetings: Effective Approaches for Supporting Asian Families of Children With IDD in Special Education

Family involvement is an essential component of the special education process for youth with intellectual and developmental disabilities (IDD). In addition to the legal requirement that parents should be equal partners in the decision-making of the student’s IEP program (IDEA, 2004), a bulk of empirical research demonstrates the positive impact of parent involvement on student outcomes. However, many families face barriers to participation in the special education process. Culturally and linguistically diverse (CLD), including Asian families, especially face systemic barriers when accessing services for their children with disabilities. In order to better understand parents’ perceptions of stress in relation to individualized education program (IEP) meetings, special education knowledge, and family-professional collaborations, individual interviews were conducted with eight Asian families of children with IDD. The input provided by Asian parents provides many critical implications for practice