Availability and Maintainability Analysis for Mobile Networks in Addis Ababa
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Date
2018-11
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Publisher
AAU
Abstract
Modern society has a high dependence on communication technology with a wider range of
applications. So, service users demand an always available network to use it whenever they
wish. Thus, network operators are expected to continuously analyze the performance of their
networks and take corrective actions to make them as available as possible. Reliability
Engineering provides methodologies and techniques to analyze the reliability, availability, and
maintainability (RAM) of systems including telecommunication networks.
The main objective of this research is to perform availability, maintainability, and downtime
impact analysis as a case study of Ethio telecom (ET) mobile sites deployed in Addis Ababa,
Ethiopia. Four months mobile sites outage, active 3G mobile service users and average revenue
per user (ARPU) data are used for the analysis. The mean time between failures (MTBF) and
the mean time to repair (MTTR) are metrics used for availability analysis while maintainability
is analyzed based on the lognormal distribution of the time to repair (TTR) data.
Analysis results have shown that: (a) 91.7% of the mobile sites had an outage over four months.
(b) 69% of the total mobile sites were in an outage for 114, 592 times and 25, 676.72 hours (c)
The average availability of the mobile sites is 99.75% with a median, mean, and maximum
maintenance times of 1.9, 3.3 & 10.4 hours respectively. (d) Longer downtimes have a
significant impact on revenue, Service Level Agreement (SLA) and on customers. The results
of the research can be used as an input in network maintenance policy, strategy, and resource
planning to ensure high network availability. The MATLAB, Easy Fit, and MS Excel software
tools are used for analysis.
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Keywords
Availability, Reliability, Maintainability, RAM, Mobile Networks, Network Outage