Unavailability of a repairable system with one or two replacementoptions submarine telecommunication network

摘要

The submarine line terminal equipment (SLTE) is part of theland-based equipment of a submarine telecommunications network. It isconsidered to be a repairable system and is housed in the terminalstation (TS). This study is concerned with the methodology for thecalculation of the unavailability of the SLTE. Thetraditionally-accepted method of calculating the unavailability of theSLTE is to assume an unlimited number of spares in the TS. Because ofthe rapidly increasing capacity of submarine networks, it is becomingmore important to quantify accurately the unavailability of theequipment, taking into account the exact limited number of sparesprovided. Furthermore, the spares replacement policy has a bearing onunavailability. The Markov method is used to model the system and tocalculate the unavailability, the results are supported usingMonte-Carlo simulations. Simplified formulae are derived to approximatethe results. Numerical examples are presented to show the advantage ofintroducing a central store and to validate the approximations