Analysis of a BTS Failure Tolerant Scheme for GSM Network

Abstract

There exist many failure scenarios in GSM networks like BTS failure, VLR, HLR or other database failure etc. The cost involved with a particular failure can be accessed in terms of number of affected users and its duration. Sometimes the failure of a base transreceiver station (BTS) may have very long duration. In such a case the BTS failure is a costly affair for the operator and highly annoying for the subscribers too. Present work suggests a scheme, BFTS (Base transreceiver station Failure Tolerant Scheme) which ensures some level of service to all users despite the BTS failure. When a BTS stops all functioning, it is designated as BTS failure. BFTS has been designed with two goals: efficient utilization of channels after BTS failure and to ensure service availability to the users of failed BTS by distributing the impact of failure over other cells. Markov models have been developed for accessing the performance, availability and survivability of GSM with BFTS. Interference analysis has also been done. In order to get robust results both analytical and simulation approaches have been used. Tradeoffs between various designing parameters have been observed and discussed.