Fault Analysis and Fault Tolerance of a Base Station System for Mobile Communications

A new approach for fault analysis and the evaluation of fault tolerance (FT) schemes of telecommunication systems is described. In particular mobile base stations are considered as an example for such systems. It is shown that standard metrics for availability and reliability are in general not suitable. A new model is proposed that leads to three different metrics which measure reliability and availability from either the system or the user point of view. These metrics are used to discover the current weak spots of unreliability and unavailability and to improve them accordingly. The approach also helps to identify and to evaluate new redundancy schemes for FT improvement. Finally the metrics give the basis for selecting these schemes according to a benefit-effort ratio.