Coût de l’application - du Système de Suivi de Maintenance des sites

Chapitre 5:Modélisation du Système de Suivi de Maintenance des sites

8.2. Coût de l’application

Bell Bénin Communications dispose de plusieurs sites sur toute l’étendue du territoire national et de nombreux techniciens qui se chargent de la

maintenance de ces sites. Nous avons estimé le coût de réalisation du système de suivi de maintenance des sites pour 50 techniciens.

Les différents éléments qu’il faut prendre en compte pour l’estimation du coût sont les suivants :

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 Le modem GSM

 PC serveur

 Hébergement du mode connecté

 Le logiciel

Tableau 8.1 : Estimation du coût de réalisation

Désignation Montant(FCFA)

Serveur de donnée Modem GSM Hébergement PC serveur Projet logiciel

800.000 30.000 100.000 200.000 4.200.000

Total 5.330.000 FCFA

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Conclusion et perspectives

L’étude de la disponibilité du réseau de Bell Bénin Communications, la proposition d’une solution optimale pour la réduction du temps moyen écoulé depuis une panne jusqu’à la réparation (MTTR Mean Time To Repair) et la conception d’un système de suivi de maintenance des sites (S-SMS) capable de communiquer avec un modem GSM pour l’utilisation des ressources du réseau partenaire ont constitué le l’objet de cette étude. Notre application a permis également de garder l’historique d’une façon permanente de toutes les actions de maintenances préventive et curative effectuées ainsi que celles des alarmes survenues sur les différents sites. Elle offre la possibilité à l’administrateur de suivre son équipe même en dehors de l’entreprise et permet aux techniciens d’obtenir en un temps record des démarches à adopter pour la résolution d’une panne donnée. Ces différentes fonctionnalités qu’offre le S-SMS permettent à l’operateur de faire un bon suivi de maintenance de ses sites.

Ainsi en ce qui concerne le S-SMS, nous nous sommes intéressés dans ce document, après avoir spécifié les besoins fonctionnels de l’application et les étapes de sa modélisation, à présenter l'outil développé sur la base des différents choix techniques effectués. Le dernier volet de notre travail a été consacré aux tests des différentes fonctionnalités de l'outil. Les résultats présentés dans le chapitre 7 montrent que l’application est fonctionnelle et permet en effet, un bon suivi de maintenance des sites. Il ressort donc de ce travail un système modélisé facile à implémenter, flexible (possibilité d’installation sur la plupart des systèmes d’exploitation), réadaptable et peu onéreux. Par ailleurs, elle peut être associée aux outils de supervision existant afin d’améliorer les procédures de suivi de maintenance des sites.

En guise de perspectives, nous envisageons l’intégration d’autres fonctionnalités des outils de supervision tels que le iMANAGER. A long terme nous prévoyons faire connecter le S-SMS au serveur OMC-R pour reporter directement les alarmes survenues au niveau des sites sur les téléphones portables des techniciens et ingénieurs afin qu’ils soient informés en temps

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réseau. Pour plus de sécurité des messages d’alertes transférés sur le réseau via le modem GSM nous envisageons aussi de connecter notre application à la passerelle de messagerie le SMS-C de l’operateur. Notre ambition est de mettre l’outil à la disposition de tous les opérateurs pour l’amélioration de leurs procédures de suivi de maintenance des sites.

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Références bibliographiques

 Ouvrages

 [1] Godlewski, P., Martins, P., Coupechoux, M., 2007: Concepts Cellulaires et Paramètres Radio. Eyrolles, deuxième édition, 10-30.

 [4] Mechin, B., 2012 : Enjeux technique de la maintenance. Les sélections, première édition, 39-43.

 [5] Démoulin, C., Van Droogenbroek, M., 2004: Principes de base du fonctionnement du réseau GSM. Revue de l’AIM, quatrième édition 3-18.

 [6] Ghoumid, K., 2009 : Réseau sans fil : Ingénierie et concept cellulaire.

ENI, troisième édition, 1-22.

 [9] Eberspächer, J., Vöge, H., Bettstetter, C., Hartmann, C., 2009 : GSM – Architecture, Protocols and Services. Eyrolles, troisième édition, 290-294

 [10] Tisal, J., 1999 : Le réseau GSM. L'évolution GPRS : une étape vers UMTS. Dunod, troisième édition, 27-35

 [11] Walk, B., 2002: networking, protocols and traffic performance. ENI, deuxième édition, 39-43

 [13] Aernouts, L., 1999: Le réseau GSM. Revue de l’AIM, troisième édition, 1-17.

 [15] Girodon, S., 2002 : Réseaux GSM, GPRS, UMTS architecture évolutive pour une stratégie service. Dunod, deuxième édition, 56-58

 [19] Drucker, P., 2004 : Optimisation de l’efficacité de l’outil de production. Les sélections, quatrième édition, 5-7, 11, 20-23

 [20] Roques, P., 2008 : UML 2 Modéliser une application web. Eyrolles,

 [8] Afokpe, J., Agossou, F., 2010 : Principes de base du fonctionnement du réseau GSM

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 [14] Lagrange, X., Godlewski, P., Tabbane, S., 1997: Réseaux GSM-DCS

 [16] Manuel de sécurité du GOF, 2007 : BASE, MOBISTAR, PROXIMUS, 7-15

 [17] Harris, S., 2009: Best Practices Guide Microwave Radio Systems.

Harris Stratex Networks, 80-85.

 [18] Huawei, 2008: BTS3012 Hardware Description (for 18TRX II).

BTS3012 V300R008, 2-6, 45, 57.

Summary

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Topic:

Improving the procedures of monitoring maintenance on the mobile telephony networks sites: The study case of

Bell Benin communications.

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INTRODUCTION

The increasing need for mobility in human activities has led to the birth of mobile telephony systems. Through the obvious interest they have generated, the mobile networks have made the entrance in our morals and have become necessary means of communication [1]. Similarly, the numerous services they offer are increasing with the proliferation of their users who expect to benefit more from them; this therefore requires an increase in the capacity of these popular Mobile phone networks [2].

This increase then leads to the birth of a great number of mobile telephony operators and also to a competitive atmosphere between them as well. In order to win the maximum subscribers, they are required to have largest coverage in their country, to provide a better quality of services and thus a good continuing maintenance schedule for their respective equipments installed all over the covered territory and kept in technical areas called GSM sites [3]. In fact, to cover their territory, GSM mobile telephony operators establish a large number of sites so that customers can have access to the services they offer.

In order to avoid poor quality of services (degradation of the voice, radio link cuts,. Etc), GSM operators must conduct regular supervision on every network entity in order to prevent breakdown cases, and to early identify them and solve them on time. Therefore, they organize maintenance teams; whose role is to ensure at all times the correct operation of each device in the network. As the major concern of any operator is to ensure a better quality of services to its subscribers, Bell Benin Communications takes this challenging task to satisfy its numerous customers. Also in this same context, maintenance procedures have been established; and are performed by maintenance teams.

However, some of these procedures used for the above concern remain laborious and sometimes ineffective. This is the line in which the present project is to act. So this project aims to propose to Bell Benin Communications some maintenance procedures in order to help the operator to have optimal results and to develop an application for monitoring maintenance of its sites.

From the alarm signals generated in the network entity called OMC-R, we can

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produce the corresponding work list and archive all information concerning the actions of maintenance carried out on all sites.

This work is built on three main parts. In the first part we will introduce the GSM Networks and the full description of the equipments of a site. In the next section we will firstly analyze the procedures used by the operator Bell Benin Communications for monitoring maintenance in order to propose an optimal procedure and then specify the requirements for the design of the Monitoring System for Sites maintenance ( S-SMS). Then we will model this system and perform the technical choices for its design. The last part will present the results obtained from different tests undergone by the application and the discussion.

1. Project View

1.1. Context, justification and problematic

In the life cycle of a mobile telecommunications network, the concepts of radio coverage, quality of service and performance are vital. It is therefore essential to the mobile operator to measure, predict and optimize in real-time the performance and the quality of its network. To ensure the continuity of services offered to subscribers, devices on each site must operate continuously and without break. This situation in short and long time leads to malfunctions in the equipments; some are damaged and others need to be maintained. [4]

Non regular monitoring of these on-site equipments causes many problems in the network, enhancing thereby the degradation of the quality of service offered to subscribers.

Bell Benin Communications where we made our internship is a mobile GSM network telecommunications operator (like its competitors), which has many sites throughout the national territory. On these sites, we have transmission equipments, radio coverage equipments as well as equipments to supply energy.

Therefore, to ensure the monitoring and maintenance of the equipments on these sites, BSS technicians are informed of different alarms which occur in them at the OMC-R, them they produce a work schedule and go on the site to

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solve the problems. When they return, they write a report of the work they have performed and send it to their superior. Note that all these are made in manually. Doing so, leads so often to a loss of information on the different actions performed on GSM sites and therefore tracking this information becomes tedious, boring and sometimes even impossible. Also in case of allocation of existing sites to a new technician, it's hard for the latter to know the specific ways the different maintenance actions carried out on these sites were made. Indeed when the problem goes beyond the skills of the technicians at level 1 they bring it to engineers and technicians of the upper level which is Level 2. These latter go on the site and try to solve the problem, in case they too fail, they call for Level 3 which are the engineers the manufacturer.

The purpose of this end training project for the graduation for design engineer is to analyze the procedures followed by the operator Bell Benin Communications in monitoring maintenance, to propose an optimal procedure and develop a Monitoring System for Sites Maintenance (S-SMS). On the base of the alarm signals collected from the OMC-R, this tool will provide the technician in charge of the site with the methodology to be used to resolve the failure; produce the work schedule so that the technician will just have to print and then go to work. After the intervention on the site, the technician can enter in the application and edit the report which will be automatically stored on a server; Doing so, will help to easily track information about a site and archive them. In addition, the S-SMS informs technicians every day of the preventive maintenance actions they have to perform by means of message alerts they receive on their mobile phone.

1.2. Project Objectives

The maintenance procedures of mobile networks are not standard; this project will therefore aim to cope with those procedures in use in Bell Benin Communications. It will help technicians and engineers at Bell Benin Communications to automatically generate the work schedule for a technician (engineer) from alarms collected at the OMC-R, to propose to technician (engineer) the procedure to follow in order to resolve the detected failure and archive information concerning the maintenance of its sites.

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functions:

Generating automatically the work schedule for a technician, checking procedures to solve troubleshooting and alarms, and archiving permanently the information on the different actions performed on the sites;

Managing the materials used on sites;

• Saving information about preventive and curative maintenance for a long period;

• Informing technicians about the daily preventive maintenance actions they have to perform by means of alert messages they receive on their mobile phone;

• Client-server Functions:

- Server Side

o The rights to create, delete, and modify user accounts.

o The right to allocate sites for technicians, to modify information about a site, to assign sites belonging to a user to another user.

o The right to provide information about the equipments installed on each site.

o The right to generate a work schedule and assign it to a technician.

- Client side

o The right to be informed of alarms and anomalies.

o The right to view the list of materials.

o The right to view the report and the work schedule of other technicians.

o The right to make research on a given faillure.

o The right to transfer his/her work schedule to another technician.

o The right to generate a work schedule.

o The right to edit a work report.

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2. Generalities

2.1. Architecture of the GSM network

The architecture of a GSM network can be divided into three subsystems:

• The radio subsystem containing the mobile station, the base station and its controller.

• The network or routing subsystem.

• The operational subsystem or operation and maintenance subsystem.

Figure 1.2: General architecture of a GSM network [8]

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2.2. GPRS Network

GPRS Network adds a certain number of the module on the GSM network without changing the existing network. Thus the entire modules of GSM architecture are kept safe [15]. Particularly the radio subsystem concerned by our work remains unchanged during the implementation of the GPRS networks.

Figure 1.3: Architecture of a GPRS network [15]

2.3. Presentation of GSM site equipments

The BTS is located on GSM site with many other facilities to ensure the continuity of the radio transmission. The figure below shows the description of the elements present in a GSM site.

3.1. Types of maintenance used by Bell Benin Communications

In Accordance with the standard NFX 60-010 published by AFNOR in May 2002 regarding the types of maintenance used in mobile telephony networks, Bell Benin Communications uses two types of maintenance which are preventive maintenance and corrective maintenance.

Bleu Rectangle: Elements for network coverage

Blue circle: Elements for network management

Blue circle not in full: Elements of associated network to the data bases

Green circle : GPRS Network modules

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• Preventive maintenance

Preventive maintenance is to prevent cases of failure that can occur.

Therefore to ensure the efficient operation of the various equipments of the radio subsystem, Bell Benin Communications has a server (M2000) that helps to supervise from a far the various equipments installed on the sites and BSC.

By connecting to the server one can know the operating status of each device.

Some preventive maintenance actions are performed from the center just by connecting to the server while others require the presence of technicians on the sites. Table 3.2 presents some preventive maintenance actions performed at BBCom.

• Corrective maintenance

Corrective maintenance is performed to correct a failure. To perform this task on its numerous sites, Bell Benin Communications has an entity called OMC-R that helps to collect the various alarm signals that occurred on all sites.

These alarms are sorted according to their degree of emergency (minor, major and critical), for example, a critical alarm type indicates that the site is stopped and therefore a corrective maintenance action must be performed.

3.1.1. The monitoring maintenance procedure adopted by Bell Benin Communications

To monitor maintenance on its sites Bell Benin Communications has established three levels of maintenance and separated the transmission of energy.

• First level

The first level of maintenance at Bell Benin Communications is composed of climbers and technicians (transmission, power) who have received a specialized training which enables them with the ability to analyze and diagnose troubleshoots (failures). So if a failure occurs on a site the first level goes to the site and tries to solve the problem. If, despite their many attempts the problem is not fixed, then they call for the Level 2.

• Second level

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comprises of supervisors, energy and transmission technicians, and the officer in charge of the technical division. They have received a highly specialized training with the ability to analyze the overall network operation. When a problem is beyond level 1, they are called for. The members of this level assemble to analyze the problem. When the solution is found they go on the site to resolve the problem. But if despite their many attempts they fail, then they are called Level 3.

• Third level

The third level of maintenance consists of Huawei engineers. Indeed, when a problem is beyond the scope of level 1 and level 2, they pass it to level 3 which try to find a solution to this problem. Note that no problem can exceed the skill of level 3.

Senior Engineer

BSS / Transmission Engineer Energy/Environment Engineer

BSS/Transmission Technicians Energy/Environnement Technicians Manufacturer

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3.1.2. Working Group Constitution and Study Organization

Given that the operator of Bell Benin Communications network has many sites all over the country, the establishment of the working group that must perform the maintenance of these sites becomes a critical task. On a mobile telephony network site we find transmission equipments, energy equipments and mechanical equipments as well. Therefore the Level 1 Team is composed of transmission technicians, energy technicians and mechanics technicians. So, when there is a failure on a site alerted by the alarm at the OMC-R, the concerned technician goes to the site to repair. But sometimes alarm indicating a failure of transmission, energy or mechanical occur and by visiting the site you realize that there is another maintenance action we must first perform. For example the TRX Voltage alarm which may be caused by the failure of the TRX card (transmission problem) may have occurred because the energy bay no longer delivers 48V (energy problem). This greatly affects the availability of the network since it increases the mean time to repair (MTTR). Therefore we suggest that whenever there is a breakdown on a site, all the team of level 1 (radio technician, mechanical technician and energy technician) should go on the site to solve the problem in order to reduce the mean time to repair and optimize availability.

To strengthen the working group and reduce the mean time to repair (MTTR), we suggest Bell Benin Communications to train technicians of Level 1 and help them to have a certification from the manufacturer. So we suggest to Bell Benin Communications the following flowchart.

Figure 3.4: flowchart of the monitoring maintenance procedure used at Bell Benin Communications

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Tasks Grouping

Grouping different tasks enable us to:

• Permanently have the history all maintenance actions performed: this functionality was integrated into the S-SMS;

• Upgrade the existing program for preventive maintenance: To evolve the existing preventive maintenance tasks, we integrated into S-SMS a functionality to alert technicians every day about maintenance actions they have to perform;

97 BSS/Transmission

Technicians

BSS Manufacturer Energy Manufacturer

Senior Engineer

Figure 3.6: Flow chart for maintenance monitoring procedure

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• Reinforce the work team: To strengthen the work team we proposed Bell Benin Communications to offer training to its technicians who go on sites to be certified by the manufacturer. This will enable the operator to have a team that is efficient;

• Resolve issues of material nature;

4. Development of monitoring maintenance on site (S-SMS) 4.1. Requirements Specification

The tool we have to design is among the site supervision tools with the specification to display all preventive and corrective maintenance actions performed on a site, and to alert technicians by SMS if a preventive maintenance action is to be performed, and to help the technicians’ manager to supervise his/her team from outside the company and even from outside

Dans le document AMELIORATION DE LA PROCEDURE DE SUIVI DE MAINTENANCE DES SITES DES RESEAUX DE TELEPHONIE MOBILE : (Page 104-141)