FMEA driven Markov for Bluetooth 4.0+ connectivity devices: A practical approach for quantitative reliability prediction
Soheil Sobhani, Ioannis Chountalas · 2017
Hearing solutions are not only relevant for human interaction but also for enabling the benefit of communication with other devices featuring audio capabilities such as smartphones and TV. Bluetooth is a widely spread wireless connection protocol that is called upon to meet such demands. It operates in the internationally allocated, unlicensed Industrial, Scientific, & Medical (ISM) frequency spectrum. Bluetooth Low Energy (BLE), as a connectivity solution with high demands for power conservation accompanied with size limitation, can meet these demands. However, the lack of proven field data for BLE can be the root of uncertainties related to perceived quality of the interface. The main function of BLE in the H.A industry is to provide an audio and/or control interface between the Hearing aid and an external device. This function is investigated in this study. The mentioned function can be divided into 3 different operational modes; (I) pairing, (II) audio streaming and (III) control application. Some of the operational modes can potentially fail, while at the same time the rest remain operational. Since BLE has the aforementioned multistate functionality, the Markov process can be used to provide a practical approach for BLE functionality modeling. The method followed here is to group failure modes according to their severity ranks in the Failure Mode and Effect Analysis (FMEA) table. Accordingly, the transition from initial state means transitioning to higher severity in FMEA. Thereafter, the state transition rates can be obtained from the occurrence likelihood of the failure causes and their related detection likelihood. It is henceforth straightforward to solve the Markov chain by establishing the states matrix, the time dependent equations and steady state probabilities.