Reliability Evaluation of Multi-State Communication Systems
Mohamed Abdulrahman AL-Amoudi · 2019
Reliability measures the ability of a system to perform its intended functions. It is one of the most critical performance measures of today’s complex systems, such as transportation systems, power systems, and communication systems. This dissertation studies the Reliability Evaluation of Multi-State Communication Systems by using both manual and automated methods to evaluate basic reliability measures of multi-state systems in general. The dissertation places a particular stress on systems used to model communication systems such as the multi-state k-out-of-n system. The reliability metrics studied include reliability per se, its derivatives (for assessment of importance metrics) and its integral (for assessment of MTTF). Out of many approaches for evaluation of reliability for multi-state systems, this dissertation employs two distinct general approaches. The first approach is a generalization of switching-algebraic or Boolean-domain approach for two-state or binary systems. The second approach is also a generalization of a technique used for binary systems, viz., the technique of formulating a solution via recursive equations together with boundary conditions. The dissertation starts with an introduction to multi-state systems, classification of their types, and a discussion of the reliability of optical fiber cables. Next, reliability evaluation of a communication flow network as a multi-state system, is performed via a brute force exhaustive (BFE) method. This is followed by a switching –algebraic analysis of multi-state system reliability including a discussion of advantages of working in the switching domain, and a binary analysis of a typical multi-state system. Reliability analysis of the multi-state system is reported using multi-valued logic. In another approach, the dissertation explores recursively-defined combinatorial functions in the case of binomial and multinomial coefficients and probabilities. Finally, the dissertation proposes techniques to evaluate certain importance measures such as the Birnbaum importance, metric.