Presentation on theme: "Abstract The engineering internship is about 600-640 hours (75-80 days) full time work placement with an industrial partner conducted as an alternative."— Presentation transcript:
Abstract The engineering internship is about 600-640 hours (75-80 days) full time work placement with an industrial partner conducted as an alternative pathway to an engineering thesis for final year engineering students at Adama science and Technology University. The purpose of internship is to provide engineering students with experience to the world of engineering practice through a period of work place employment. This report details the work performed during an 80 days internship placement with the western regional telecommunication. The report features Western regional ethiotelecom description including several telecommunication sectors to make clear communication for subscribers by solving communication challenges of this region. The future work required to be completed as the continuation of a work performed during internship placement is presented.
Acknowledgement First of all we would like to express thanks to almighty God. Second, we would also like to thank Adama science and Technology University for organizing the internship program at all for his engineering students alike. Again show appreciation Western regional ethiotelecom for permitting the semester internship to be train with their company. We would like to express gratitude to Ato Aman Mieso the Electrical Engineering department Head, Ato Temesgen the electrical engineering internship student advisor. We would also like to give special thanks to our supervisor, Ato Tilahun Ejigu and operation and maintence manager, Ato Mulatu and other operation and maintenance worker who assisted us by sharing their knowledge and experience throughout their working time in our internship duration. Finally, we would like to show gratitude to other western regional ethio-telecom workers that gave their knowledge and other efforts to make us perfect with works.
Introduction Western Regional Ethiotelecom is situated in the West of Ethiopia which is found at Nekemte town 330km from Addis Ababa 430 from Adama. This region includes seven sections, such as indirect channel, direct channel, fixed access network, operation and maintenance, Business partner, finance and physical security and 12 shops in different areas. This is final report for Electrical engineering in communication stream semester internship.the internship was undertaken to finalize this semester industry internship for engineering students. This specific internship was undertaken at Ethio telecom western regional division, where duties were assigned providing the experience as a product specialist.Over the course of internship a variety of activities were experienced, both technical and process related.This provide a range of valuable job skills which would be able to applied in future position both with Ethio telecom and western region division in general.
2. Background of Ethio telecom The introduction of telecommunication in Ethiopia dates back to 1894. Ethiopian Telecommunications Corporation is the oldest public telecommunications operator in Africa. In those years, the technological scheme contributed to the integration of the Ethiopian society when the extensive open wire line system was laid out linking the capital with all the important administrative cities of the country. After the end of the war against Italy, during which telecommunication network was destroyed, Ethiopia re-organized the Telephone, Telegraph and Postal services in 1941. In 1952 the Imperial Board of Telecommunications (IBTE) was established by proclamation No. 131/52 in 1952. The Board had full financial and administrative autonomy and was in charge of the provision and expansion of telecommunications services in Ethiopia. The Imperial Board of Telecommunications of Ethiopia, which became the Ethiopian Telecommunications Authority in 1981, was placed in charge of both the operation and regulation of telecommunication services in the wake of the market reforms. In 1996, the Government established a separate regulatory body, the Ethiopian Telecommunication Agency (ETA) by Proclamation 49/1996, and during the same year, by regulation 10/1996, the Council of Ministers set up the Ethiopian Telecommunications Corporation (ETC). Recently, the Ethiotelecom company has been organizational structured by 1 head quarter,6 zonal offices and 8 regional offices providing different services such as fixed telephone, mobile telephone, internet, CDMA, etc through its offices.Western region is among 8 regional office and plays vital role in ethiotelecom on behalf of it self.
2.1 Company mission and value As a continuation of the last five-year plan and after concentrating its efforts on education, health and agriculture, the Ethiopian government has decided to focus on the improvement of telecommunication services, considering them as a key lever in the development of Ethiopia Ethio telecom is born from this ambition of supporting the steady growth of our country. Ethio Telecom wishes to implement state-of-the-art processes, to develop reliable network infrastructures and to provide the best quality of services to Customers. This is the mission of Ethio telecom; that drives all Ethio telecoms actions. To ensure that Ethio Telecom runs parallel with top telecom operators, the Ethiopian government has reached an agreement with France Telecom, one of the world’s leader telecommunication companies. This agreement will help ETHIO telecom to improve its management capability through the transfer of world-renowned know-how and skills. While meeting international standards, Ethio Telecom remains faithful to his values: Ethio Telecom commit to understand, meet and exceed the telecommunications needs and expectations of our country at large and of customers in particular Ethio Telecom respect customers and recognize that their revenues allow to operate Ethio Telecom recognize that the company employees are the most valuable asset and want to create an efficient corporate management environment that allows them to develop and grow Ethio Telecom will commit to high-level job performance, customer service quality, organizational excellence and continuous improvement in all areas
Ethio Telecom will stay motivated and encouraged to meet all the challenges that will face Ethio Telecom will make every effort to achieve a superior financial return Ethio Telecom uphold ethical standards, being honest in all assignments Ethio Telecom will hold employees accountable to all their stakeh
2.2 Company Objectives, Services and products In line with its ambitious mission, Ethio Telecom has ambitious goals: being a customer centric company offering the best quality of services meeting world-class standards building a financially sound company To reach these goals, all Ethio telecom divisions will focus on: developing and enhancing network and information system ensuring easy access and coverage to the whole population creating a strong brand developing human resources management implementing control standard processes improving financial, sourcing and facilities processes
Ethio telecom offers a wide range of products and services tailored made for Enterprise customers and non enterprise customers. Ethio telecom offer Fixed wire line and wireless services, mobile services, Internet and Data services as well as 3G services like WCDMA and CDMA through the newly deployed Next Generation Networks(NGN). Owing to nationwide huge capacity Ethio telecom provide Enterprise customers a reliable and affordable Internet and data services which facilitate their business and increase their productivity by connecting them to local and international partners
3.Management, Training and employee information Ethiotelecom has different departments in different places. Here, at western region we assigned to work in operation and maintenance department for all internship session. This section covers all operation and maintenance case of western region. So that, it consist of seven different working section. At the day we began intern to this region we introduced with operation and maintenance manager and he assigned a supervisor for us. On the next day, after we have introduced with our supervisor and he shown us different working sections of this region and supervisor assigned us to work with their coworkers. We introduced to the supervisor and with other operation and maintenance worker for two weeks first. After that, we assigned to see different western regional Ethiotelecom equipments and how they are configured these includes RAN system, transmission system, exchange, routers, PSTN, BSCs, BTSs and the like. To have detail knowledge about this equipment the manual of some equipment is give for us by pdf and by hard copy/module/.After we have completed these duties we are assigned to see all operation and maintenance section turn by turn. First turn RAN section, second turn core section, third, fourth, fifth IP section, transmission section, payphone section respectively. Finally we are assigned to see power section. For each section we are assigned to work for more weeks.
Our supervisor has helped us to succeed in our assignments in a good manner. After we encountered about a week one personal computer is given for us from his working section. There are free internet access about 100Mbps and we have used for reading and checking our account and such a like. Our supervisor guided us what we have to do and what we haven’t do in our daily working at every working time and he took attendance to follow us whether we present or not. We ask our coworkers if there is unclear thing while we are on working. The other responsibility we had during our internship is respecting working ethics like arriving on time, cooperation with coworker, accepting and respecting daily duties given by our supervisor and the like. Western region has many workers in different departments. It is difficult to mention all departments on this report because of its wideness but, let us mention the main department of this region.
1.Operation and maintenance department This department deals with all operation and maintenance of RAN, corenetworks, transmission, exchange, PSTN, payphone equipments sothat, this department is back bone at this level. 2.Fixed access network department Does the operation maintenance activities of copper cables and optical fibers. 3.Human resource management department This department manages human power with the intention that, employee appraisal is conducted once a year for employee and managers and also used two types of standardized forms i.e, administrative and clerical, and management and professional performance evaluation format respectively. Progress of employee performance is measured periodically, provide feedback and support employees to achieve both quantitative and qualitative targets.
4. Specific job information 4.1 operation and maintenance department 4.1.1 Radio Access network System (RANS) section In this section we have seen different types of BTS, BSC different vendors’ equipments. That equipment plays their own role for mobile communication. Let us discuss in short and brief. Base transceiver station (BTS):- BTSs-houses the radio transceiver of the cell and handles the radio links protocols with the mobile
-connects to a number of mobile stations (MSs) and each MS establishes connection through the user interface um where um is the ISDN U interface for mobile. -A BTS is also connected to a BSC at through the A bis interface which transmits and receives data. With four multiplexed channels of 16 kbps or with a 64 kbps channel. In this section we seen two BTSs. one BTSs operates to 900MHZ which is corresponds to out side nekemte town for rural areas of nekemte town. The other BTS is operates to 1800MHZ which is used for nekemte town. These BTSs is corresponds to GSM. Similarly two CDMA’s BTSs is found in this section which is operates to frequency of 800MHZ and450 MHZ which is used to cover town and rural area of Nekemte respectively. Main function performed by the BTS Formation of cells using appropriately directed antennae Processing of signals Amplification of signals to acceptable strength so that they can be transmitted without loss of data. Channel coding and decoding (for example, coding voice into bits so that it can be transmitted at 13kbps and decoding received coded signals back to voice). Frequency hoping so that multiple channels for various mobile stations can operate simultaneously using different channel band frequencies Base station controller (BSC) In this room there are three racks serves for BSC which is used to control western regional ethiotelecom BTSs and it manages radio resources (channel set up, hand over)for one or more BTSs.BSC connected to an MSC in the networking and switching layer using an interface A.
Important functions performed by the BSC Processing of signals Controlling signals to the connected BTSs and control of handover of signals from one BTS to another with in a BSS Control of handover of the signals from BSC to MSC(Mobile switching center) Mapping a signal of a channel at a given instant receives signals from a BTS at 16 kbps through and interface to MSC at 16 kbps Alternatively, may have to interface to a PSTN switching centre at 64 kbps through a fixed line network Reserving radio frequencies and frequency hoping(For example, multiple BTSs operate simultaneously by using the different frequencies at a given instant) Location registry for the MSs Authentication, encryption,and decryption of data BSC and BTS maintenance system Daily routine maintenance: this includes 1. Equipment environment:-This includes temperature requirement 15 o c_30 o c. 2. Equipment running status:-This can be a. querying the alarm information b. running status of boards:-It is required to check whether the indicators for each board in the rack are normal. If any alarm indicator is on, it is required to maintain and eliminate the fault. By the different flashing meaning of the indicators’ we can determine the running status of the equipment. Regular routine maintenance:-This can be considered as 1. Checking BTSs and BSC rack modules:-checking the amount, model and version of the spare modules once a week. 2. Hardware checking:-This includes cleaning the rack, checking
power cables and ground cables Typical maintenance method:-In daily maintenance, several typical maintenance methods can be used as follows: 1. Observation method:-Locating the fault by viewing the alarm information of the LMT of the BTS. The observation method is the first method the maintenance personnel should use in case of fault occurrence. Making a correct judgment on the observation result is a key step for correct analysis and handling of the Fault. Therefore, the maintenance personnel must be very familiar with the indicator statuses of the boards, and fully aware of the meanings of the alarm information of different levels on the LMT of the BTS. 2. Plugging/unplugging method:-When a circuit board is initially found faulty, plug/unplug the circuit board and the external interface connector to eliminate such faults as poor contact or processor abnormality. Make sure that the board must be hot-swappable when this method is applied. 3. Replacing method:-The replacing method is to check the fault by replacing the circuit board in question with a normal circuit board. When the plugging/unplugging method fails, the replacing method can be applied.
4. Isolation method:-When a part of the system is faulty, the involved circuit board or racks can be isolated to check whether the fault comes from mutual impact. For example, a typical application of the isolation method is to self-loop the I/O interface of a circuit board so as to isolate and solve the problem of the related system. 5. Self-test method:-When the system or circuit board is powered on again judge if there is any fault by way of self-test. Usually, when a circuit board is re-powered on for self-test, the indicators on its panel will flash regularly, so that we can check whether the circuit board itself is faulty. 6. Pressing method:-Such faults as poor contact can be removed by pressing the chips and cable connectors.
4.1.2 Transmissions, access and transport section The ethiotelecom objective is to produce high-quality voice, video, and data Communication between any pair of desired locations, whether the distance between locations is 1 or 10,000 km. The distance between the two locations determines the type of transmission equipment used for setting up the connection. First, communication over a distance on the order of a few meters, such as within a building, is done using metallic wires, optical fibers or radio. Any routing of information within the building is done by switch on the premises, a switch known as a private branch exchange (PBX).When the distance is extended to a neighboring building or to span a distance within a village, town, or city, the local telephone network is usually used. This entails making a connection to the nearest switching exchange by a pair of copper wires or radio, routing the initiating party to the desired receiving party, and completing the connection on the recipient’s pair of copper wires, or radio, which are also connected to the nearest exchange. The next stage of interconnection is intercity or long-distance, connections. The contenders to fill this role are microwave radio, optical fiber, and satellite. Fierce competition has emerged among these three technologies. Microwave and satellite communications are far more mature technologies. For wideband services optical fiber will no doubt be used in the future. There are many other instances where the choice between microwave radio
and optical fiber systems are not so clear. The decision might be in favor of satellite or microwave radio for very rugged terrain, or fiber optics for very flat terrain. When the region under consideration contains both very flat and very mountainous areas, a combination might be suitable. In addition to above, we have seen various transmission system used to transport information from one place to other place. Let us see one by one. 1. Microwave Microwave communication is the transmission of signals via radio using a series of microwave towers. Microwave communication is known as a form of "line of sight" communication, because there must be nothing obstructing the transmission of data between these towers for signals to be properly sent and received.Additiionally, we have seen different types of microwave dishes directed to different microwave repeaters. This microwave repeater increases the power gain which will be transmitted from BSC. So that, there are several microve repeaters available for this region. Fig 4.1
Figure 4.1 shows a simplified microwave link incorporating just one regenerative repeater and two end terminal stations. The terminal stations house switching equipment that connects the customers to the long-distance paths. In this illustration, a large number of customer signals (around 2000) are multiplexed together into a single signal, ready for transmission over the microwave link. The signal is converted to the microwave frequency (around6 GHz) and transmitted over a path of typically 30 to 60 km from station A to the receiving antenna at the repeater station. The repeater either (1) simply amplifies the signal and sends it off on its journey using a different micro wave frequency to minimize interference, or (2) it completely regenerates the individual pulses of the bit stream before reconverting the signal back to a microwave beam for onward transmission. Station B receives the microwave signal, processes it, and unravels the individual channels ready for distribution to the appropriate customers at these end users. 2. Fiber optics Fiber-optic communication is now the dominant data transmission method. However, microwave communication equipment is still in use at many remote sites where fiber-optic cabling cannot be economically installed. At present cisboarder backbone network is microwave transmission system, as telecommunication service is becoming in Ethiopia.The existing back bone transmission system cannot meet the needs of the people. Therefore ETC confirmed eight optic fiber lines through out the country to be builted; its main aim is to resolve communication problem of communication between country capital and states. This Nekemte branch includes eleven stations(Addis Ababa, Holota, Adis Alem,Welenkomi,ginchi,Ambo,Guder,Gedo,Ijaji,Bako,Sire and Nekemte).This Nekemte branch also extended up to Asosa regions by branching to different western regional towns. Here one SDH 2.5G and one SDH 155M system is equipped in the route.
All optical fiber out from or into all stations terminated at the termination box on the ODF. The termination box connected to flange; using single ended pigtail fibers, and connected to SDH equipment using dual ended pigtail fibers with FC/PC. The 34Mbits/s (E 3 ) or 2Mbits/s (E 1 ) port of SDH equipment connected to DDF in the equipment rooms. Using coaxial RF cables. The 155M outlet fibers of the branches terminated on ODF in the transmission rooms, using dual ended pigtail fibers with FC/PC. In this transmission system communication cables includes trunk cables, pigtail fibers, clocking wire and alarm wires and network wires. All these cables run in cable trays and placed in order and bound fitly 3. VSAT (Very small Aperture Terminal) Two Stations on Earth want to communicate through radio broadcast but are too far away to use conventional means. The two stations can use a satellite as a relay station for their communication. One Earth Station sends a transmission to the satellite. This is called a Uplink. The satellite Transponder converts the signal and sends it down to the second earth station. This is called a Downlink.
The Broadband VSAT is a satellite system especially applied to the remote areas of the country. The country uses the Broadband VSAT network for the provision of triple play services for high schools, universities, research centers, Woredas and Non Governmental organizations. School Net: with the aim of providing similar standard education to high schools throughout the nation, the program was launched in February 2004. At this time 1093 high schools and preparatories are getting the service with the help of 12 channels; in addition to this the 197 of the high schools have got access to internet service with a capacity of 256kbps. WoredaNet: The WoredaNet Network has enabled woreda centers of the country with the opportunity to use voice, data and multimedia services. At this point in time 631 woredas are getting data, internet and Video conferencing service with a maximum capacity of 512kbps. AgriNet: This AgriNet Network has a total of 35 VSAT stations which are agricultural institutions connected with each other and the federal government for Internet service. The advantages of satellite communication over terrestrial communication are: The coverage area of a satellite greatly exceeds that of a terrestrial system. Transmission cost of a satellite is independent of the distance from the center of the coverage area. Satellite to Satellite communication is very precise. Higher Bandwidths are available for use The disadvantages of satellite communication: Launching satellites into orbit is costly. Satellite bandwidth is gradually becoming used up. There is a larger propagation delay in satellite communication than in terrestrial communication
4.1.3 Internet protocol (IP) and IT section Ethio telecom’s IP Network is constructed in such a way that it can provide NGN (including GSM, Fixed NGN, CDMA, IP/Broadband Access Network services including Value Added Services) at regional cities, major cities, sub cities, and towns. To understand easily this IP network let us show you its topology.
IP network layers and their functions 1. Gateway layer: This layer deployed in four sites and contains routers mainly functions to connect to an external network /internet/ The Ethio Telecom has built extensively Ethiopia’s internet infrastructure to give better and quality internet service. Currently; we have fifteen international internet links from Bole, Bahirdar Diredawa and Shashemene gateways. The Total Upstream /downstream bandwidth is 6475.5/6775.5 in Mbps 2. Back bone layer: Totally 10 sets of BR (T8000), distributed to five cities and each city deploys two sets of BR, full meshed connection. This layer is mainly responsible for service traffic forwarding and high capacity communication facilities. 3. Core layer: This layer is mainly responsible for service traffic forwarding, convergence and high capacity communication facilities. 4. Edge layer: Provides information exchange b/n the access and core network. It is an entry point in to carrier/service provider core backbone networks and used for aggregation of core switches
5. Acess layer: Access layer is where broadband access devices and ethio telecom ’ s other networks (GSM, CDMA, FL-NGN) are connected.
4.4. Core Network, Local Switch and MSAG Section Core network: A core network is the central part of a telecommunication network that provides various services to customers who are connected by the access networks. One of the main functions is to route telephone calls across the PSTN. Typically the term refers to the high capacity communication facilities that connect primary nodes. Core/backbone network provides paths for the exchange of information between different sub-networks Core network includes three parts:- 1. Soft switch: A soft switch has revolutionized telecom industry. Gone are the days of conventional voice switches. These days, a soft switch can work with voice, fax and video, contributing much to the recent telecommunication revolution. As a matter of fact, a soft switch is a virtual device/software that connects calls from one line to another. Since this is a virtual tool, it is entirely managed via computer. 2.Media gate way: A Media Gateway acts as a translation unit between disparate telecommunications networks such as PSTN; Next Generation Networks; 2G, 2.5G and 3G radio access networks or PBX.As the Media Gateway connects different types of networks, one of its main functions is to convert between the different transmission and coding techniques. 3. Public switching telephone (PSTN):-The basic service of PSTN refers to the basic call connection functions provided by the switch, inter office call, local call, national toll call, international toll call, tendem call and others.
MSAG:-MSAG (Multi-service Access Gateway), a reliable device of medium capacity and carrier class rolled out by ZTE, mainly develops VOIP services and broadband data services over the IP MAN or backbone network, and is primarily based on the accessing of ADSL or VDSL to realize the voice and data services simultaneously. Also, it can access the corporate users like enterprises by deploying the inner LAN to provide IP phone services. Local switch:-Is the telephone exchange in the PSTN directly serving subscribers. This serves includes dial tone, calling, features and additional digital and data services to subscribers using the local loop.
4.1.5 Pay phone and CPE section CPE:- A customer premises equipment device (CPE device) refers to a telecommunications hardware device located on the telecommunication customer's premises. This equipment might include cable or satellite television set-top boxes, DSL or other broadband Internet routers, VoIP base stations, telephone handsets, or other customized hardware. CPE equipment can be owned by the customer or leased from the telecommunications company. CPE also includes the interior wiring at the customer's location that is connected to a communication service. Payphone:- payphone is a public telephone, often located in a telephone booth or a privacy hood, with pre- payment by inserting money (usually coins), a credit or debit card, or a telephone card. Ethiotelecom facilitated the communication system as a form of payphone for rural, towns and cities of Ethiopia. Here fixed telephone, GSM, CDMA can be considered. The quality of this payphone is that; since it uses solar power it is very useful for rural areas of Ethiopia where difficult to get AC power source. Now a days rural areas of Ethiopia (kebele and wereda) uses this wireless CDMA, GSM payphone and easily can access communication networks.
4.1.6 Power and environment section This section is one of the important parts of the ethiotelecom division section. The main job of this section is managing and facilitating power supplies for this environment. Especially for equipments. To do this in a best condition this section uses different equipment and limit power specification of equipments.This equipment includes:- 1. HF- switch:-380v triple-phase with five lines and 220v single phase with three lines can be Can be accessed. -frequency: 50HZ -lighting protection added -warning of high voltage and AC failure; marking civil power and generator. 2. AC power supply:-This includes generators and hydro electric power 3. Rectifier: - AC 220V input; DC -48V out put -function of floating charge, averaging current, converting -warning of high and low voltage -Adjusting scope of DC voltage output: -50V--59V -Adjusting scope of equalize voltage: -50V-60V 4. DC power supply system:-warning of DC high voltage output, low voltage output and without -Two times discharging and battery low voltage protected. 5. Non maintenance storage battery:-low self discharge -flow and equalize charge of battery is in constant voltage -the steel anti- seismic rack or stand rack is used to fix the storage batteries.
During our internship period the responsibility given for us is covering all operaration and maintenance department sections and we have successfully seen all these section accordingly which is crucial for our stream. We were in trouble when we were working in core network and transmission section while fiber optics and telecommunication course is a base for this sections.Therefore, to be succeful in our practice we decided to read manual and soft copy after that we continued practical work. The other course we advanced while we on intern are Antenna system and design.it is also the basic in some of antenna related like MSAG,BTS,BSCs and the like configurations.The other one is Electromagnetic wave and propagation is also the basic one for such alike work, Every wave can move from one any type of antenna to another in the form of Radio wave,microwaves and fiber optics to transmissions and receiving
5. Evaluation and critique Today all of the worlds are becoming to one neighbor district through globalization and technology development in high speed, if you need any things from this world there is a competition beside of you. Therefore to become a competent of as such you have to know in every directions around that you are focusing for.Internship is the basic knowledge full for every students living in this globalized world. There is knowledge at every work industry the same as that of at school, even if there is a problem with some industries to give you a chance for more working accessibility intern students can get more knowledge more. So we are one of that! we got more knowledge related to our field from this company and we also know the working behavior, in general as we already explain it so far what we got from this intern. Any like explained above problem can be solved by the Universities or collages internship committee or other concerning parts for his trainees benefit to get productive human from this career, unless it is just merely losing a country resource and human mind. We extremely blame especially electrical department Intern holder. We never ever visited whether we on working or not. Every intern owner must have to follow and communicate to help his trainees at every time needed. As such is so worthy! Finally, since modern technologies is dynamic to go with recent technologies any education should be supported by education tour for each related course.To do so, the university should facilitate education trip in addition to internship.
5.1 Recommendation Now we would like to recommend the internship to be improved as internship student from what we face when we are on intern. First of all the university must have facilitate the place of internship for his student strictly that is favorable to follow them while on work. There was a problem with our university concerning this in fact. Most of intern students are searching company by them selves with some challenges we know. The internship students must have followed in related by the University advisors at least once per month. The problem we mentioned above favorable is here useful for our advisors to perform this actions easily. The internship student must be evaluated or have a report what they have been working every months in the form of hard copy or through e-mail to university advisors. Also there must be a neat communication between the Organization and University advisors to do this type of evaluation. Every help and supports are throughout the duration of internship placement is strictly required from every department internship concerning body. Finally; in our report we wanted to describe the topology of Nekemte BSC but because of shortage of available space we haven’t described on this report.