During training period, trainee has learnt about overall exposure of RLU exchange, telecommunication network and bsnl broadband and 3G services. MUDIT GUPTA is a student of b. tech – ivth year, S. d. College of engineering and technology, muzaffarnagar(u. p. ) . He has attended the b. s. n. l, Shivchowk, Exchange, Muzaffarnagar for six weeks. ACKNOWLEDGEMENT I am very much thankful and want to express my profound gratitude in respect of Computer Engineers, b. s. n. l. ,mzn, who permitted me for the practical training in their Department. I am also grateful to all Technical Staff of B.
S. N. L. whose transcendent thoughts were the tremendous source of inspiration and encouragement, which will be definitely important for me as far my future is concerned. They explained primary techniques in a very easy manner. I also extend my gratitude to whole staff of B. S. N. L. , Muzaffarnagar, for their kind cooperation. CONTENTS Page No. ¦ Company Profile 4-5 ¦ Vision, Mission and Objectives 6 ¦ Broadband Services 9 Technology Used 10 ¦ Wired Line 11-17 ¦ Wireless Line 18-26 ¦ Bibliography 12 COMPANY PROFILE On October 1, 2000 the Department of Telecom Operations, Government of India became a corporation and was christened Bharat Sanchar Nigam Limited (BSNL).
Today, BSNL is the largest Public Sector Undertaking of India and its responsibilities include improvement of the already impeccable quality of telecom services, expansion of telecom network introduction of new telecom services in all villages and instilling confidence among its customers. Bharat Sanchar Nigam Ltd. formed in October, 2000, is World’s 7th largest Telecommunications Company providing comprehensive range of telecom services in India: Wireline, CDMA mobile, GSM Mobile, Internet, Broadband, Carrier service, MPLS-VPN, VSAT, VoIP services, IN Services etc.
Presently it is one of the largest & leading public sector unit in India. BSNL has installed Quality Telecom Network in the country and now focusing on improving it, expanding the network, introducing new telecom services with ICT applications in villages and wining customer’s confidence. Today, it has about 47. 3 million line basic telephone capacity, 4 million WLL capacity, 48. 11 Million GSM Capacity, more than 37382 fixed exchanges, 44966 BTS, 3140 Node B ( 3G BTS), 287 Satellite Stations, 480196 Rkm of OFC Cable, 63730 Rkm of Microwave Network connecting 602 Districts, 7330 cities/towns and 5. Lakhs villages. BSNL is the only service provider, making focused efforts and planned initiatives to bridge the Rural-Urban Digital Divide ICT sector. In fact there is no telecom operator in the country to beat its reach with its wide network giving services in every nook & corner of country and operates across India except Delhi & Mumbai. Whether it is inaccessible areas of Siachen glacier and North-eastern region of the country. BSNL serves its customers with its wide bouquet of telecom services.
BSNL has set up a world class multi-gigabit, multi-protocol convergent IP infrastructure that provides convergent services like voice, data and video through the same Backbone and Broadband Access Network. At present there are 0. 6 million DataOne broadband customers. The company has vast experience in Planning, Installation, network integration and Maintenance of Switching & Transmission Networks and also has a world class ISO 9000 certified Telecom Training Institute. BSNL cellular service, CellOne, has more than 49. 09 million cellular customers, garnering 16. 98 percent of all mobile users in its area of operation as its subscribers.
In basic services, BSNL is miles ahead of its rivals, with 35. 1 million Basic Phone subscribers i. e. 85 per cent share of the subscriber base and 92 percent share in revenue terms. BSNL plans to expand its customer base from present 47 millions lines to 125 million lines by December 2007 and infrastructure investment plan to the tune of Rs. 733 crores (US$ 16. 67 million) in the next three years. The turnover, nationwide coverage, reach, comprehensive range of telecom services and the desire to excel has made BSNL the No. 1 Telecom Company of India. VISION, MISSION & OBJECTIVES
VISION: To become the largest telecom Service Provider in Asia. MISSION: To provide world class State-of-art technology telecom services to its customers on demand at competitive prices. To Provide world class telecom infrastructure in its area of operation and to contribute to the growth of the country’s economy. OBJECTIVES: (1) To be the Lead Telecom Services Provider. (2) To provide mobile telephone service of high quality and become no. 1 GSM operator in its area of operation. (3) To provide point of interconnection to other service provider as per their requirement promptly. 4) Contribute towards: (i) National Plan Target of 500 million subscriber base for India by 2010. (ii) Providing telephone connection in villages as per government policy. (iii) Implementation of Triple play as a regular commercial proposition. (5) To facilitate R & D activity in the country. Voice The majority of all telecommunication today uses Digital techniques, and the dominance of digital is so strong that in this text we will neglect Analog communication almost completely. When communicating voice digitally, the sound waves in the air must be digitalized.
This is done by sampling the sound waves: measuring their shape, and converting this measurement into numbers. These numbers are a digital form of the voice signal. At the receiver, the measurement values (called samples) are used to reconstruct the original sound wave. To be able to reconstruct the voice with sufficient quality, the number of samples taken (called the Sampling-rate) and the accuracy of each sample (called the Resolution) must be sufficient. This is a trade-off, because the more samples, the more digital numbers needs to be transmitted, and this costs money.
As a good compromise for understandable voice, the telecom community agreed to take 8000 samples per second, each 8 bits precise. This will not result into perfect audio-quality, but it is enough to understand the person on the other side of the line. As you are converting the sound waves to digital numbers, you create a continuous stream of information flow: every second you generate – transport – terminate 8000*8 = 64000 bits. This amount is called the Bit-rate. As a result a single digital voice connection is often referred to as a 64 kbps (kilo-bits-per-second).
This continuous stream lasts as long as the phone conversation lasts, typically a few minutes. Note: – As a comparison, an audio CD signal uses 44100 samples per second, each 16 bit precision, and two channels (left+right) to provide stereo. You will agree that CD sound quality is much better than a phone-line, but the price for this is that you need to transport 1. 411 Mbps for the CD (mega-bits-per-second), where only 64 kbps for a telephone line. Data When computers or machines communicate with each other, they usually don’t send a continuous stream of information.
Typically a computer needs some limited input data, then processes this, and responds with a limited amount of result data. Therefore data communication is using the concept of information packets a group of information bits. So one computer sends a packet of input to the other computer, which processes it, and then returns a packet with the results. BROADBAND SERVICES Broadband is often called high-speed Internet, because it usually has a high rate of data transmission. In general, any connection to the customer of 256 kbit/s (0. 256 Mbit/s) or more is considered broadband Internet.
The Organization for Economic Co-operation and Development (OECD) has defined broadband as 256 kbit/s in at least one direction and this bit rate is the most common baseline that is marketed as “broadband” around the world. Telecommunication regulatory authority of India(TRAI) defines broadband as “an always on data connection that is able to support interactive services including internet access & has the capability of the minimum download speed of 256Kbps to an individual subscriber from the point of presence of the service provider intending to provide broadband service where multiple uch individual broadband connections are aggregated & the subscriber is able to access these interactive services including the internet through the POP. The interactive services will include any services for which a separate license is specifically required. For example- real time voice transmission, except to the extent that it is presently permitted under ISP license with internet Telephony”. TECHNOLOGY USED Broadband access technology is classified into two categories: Wired Line * DSL (Digital subscriber’s line) * Cable Modem * PLC (power line communication) * Optical fibre technologies Wireless Line * 3G Mobile Wi-Fi (Wireless fidelity) * Wi-Max * FSO (Free space optical) * LMDS & MMDS * Satellite Wired Line: * DSL: Digital subscriber lines apply modern digital techniques on twisted pair medium to deliver new services over existing infrastructure. The bandwidth and quality of a typical analog telephone line is relatively low (300… 3400 Hz). This is mainly because there is a wide variety of types, lengths, qualities, etc of twisted pairs used, and an analog line must assume the worst-case common denominator of all. However, today’s more powerful signal processing and computing techniques allow building equipment hat adapts to each particular twisted pair, optimizing the use of it case by case, and resulting in much higher throughputs. For the Telecom operator, the advantages are: – * No additional cable-cost: uses existing telephone line. * Telephone network is not used for data-services, like accessing the Internet. Telephone networks are dimensioned for phone calls, not for accessing the Internet. For example the average phone call duration is 100 seconds, when ‘surfing’ the Internet this is much longer, resulting in congestion in the telephone network. Advantages for the end-user: – High throughput up to Mbps. * Telephone is still available when surfing the Internet, telephone and data-services can be used at the same time. HDSL XDSL is a family name for a number of similar techniques. The x is a placeholder for several variants of Digital Subscriber Line (DSL). The first one, which was developed, was High Speed Digital Subscriber Line (HDSL) It is a symmetrical technique, the same bandwidth is available in both directions. HDSL is typically deployed in the network where 2. 048 Mbps are needed, but only twisted pair (no coax or fiber) is available. ADSL
Asymmetrical Digital Subscriber Line (ADSL) is the best-known variant of XDSL: The main principles are the same, but the bandwidths are divided Asymmetrical: more bandwidth is made available from network to user (Downstream) then from network to user (Upstream). This matches with typical residential applications, Such as: – * Video-on-Demand (VOD): video, typically a few Mbps going downstream, with the user control (selecting the video, play, stop, rewind, etc) only a few kbps going upstream. * Internet: WEB-contents going downstream are megabytes; user requests are only a few hundred bytes.
Figure: – Internet Access Provider, ADSL VDSL Digital subscriber lines make a trade-off between bandwidth and distance: the shorter the line, the higher the throughput. As a result of this, a number of variants of DSL-techniques are being developed, from long distance – low bandwidth to short distance – high bandwidth. Another parameter is the division of Upstream/Downstream bandwidth. This can be: – * Symmetrical: the same in each direction, * Asymmetrical, fixed * Asymmetrical, dynamic: the total bandwidth, upstream+downstream is fixed, but at any time this total can be assigned in a certain ratio to either direction.
New DSL variants using these new techniques are called Very High Speed Digital Subscriber Line (VDSL) Figure: – Different DSL technique CABLE MODEM A cable modem with a splitter can provide Internet access to multiple PCs, if they are connected via a LAN. * Tuner converts TV channel to a fixed lower frequency (6 to 40 Mhz). * Demodulator performs A/D demodulation, error correction & MPEG synchronization. * MAC extracts data from MPEG frames, filters data for other cable modem, runs the protocol. * Burst modulator performs RS encoding modulation frequency conversion/A conversion. Interface can be PCI bus, universal serial bus, Ethernet or others. Figure : -Cable Modem POWER-LINE COMMUNICATION(PLC) This is a new service still in its infancy that may eventually permit broadband Internet data to travel down standard high-voltage power lines. Broadband over power lines (BPL), also known as Power line communication, has developed faster in Europe than in the US due to a historical difference in power system design philosophies. Nearly all large power grids transmit power at high voltages in order to reduce transmission losses, then near the customer use step-down transformers to reduce the voltage.
Since BPL signals cannot readily pass through transformers, repeaters must be attached to the transformers. In the US, it is common for a small transformer hung from a utility pole to service a single house. In Europe, it is more common for a somewhat larger transformer to service 10 or 100 houses. For delivering power to customers, this difference in design makes little difference, but it means delivering BPL over the power grid of a typical US city will require an order of magnitude more repeaters than would be required in a comparable European city. The second major issue is signal strength and operating frequency.
The system is expected to use frequencies in the 10 to 30 MHz range, which has been used for decades by licensed amateur radio operators, as well as international shortwave broadcasters and a variety of communications systems (military, aeronautical, etc. ). However there are some disadvantages of using PLC communication: N/w characterstics & devices can advesely affect signal strength & quality. Electronic loads & nearby high frequency radiation sources may cause high frequency noise that interferes BPL. Some PLC systems are not fully operable at very low or no load without battery backup.
Physics limits frequency on power lines to ; 100 Mhz. BPL is not likely to be available soon for high voltage(;66Kv)power lines. Conventional electronic surge arrestors severely attenuate BPL signals. OPTIC-FIBRE TECHNOLOGY Currently fibre costs are high as compared to copper but there is a trend towards decreasing costs of optical fibre cables and photonics employed. To carry same information as one fibre cable we would need hundreds of reels of twisted wire copper cables. Fibre is 23 times lighter than copper cable & 36 times less in cross section. Advantages Of Optic-Fibre Communication: Small Size and Weight: – Optical fibers have very small diameters which are often no greater than the diameter of a human hair. Hence, even when such fibers are covered with protective coatings they are far smaller and much lighter than corresponding copper cables. This is a tremendous boon towards the alleviation of duct congestion in cities, as well as allowing for an expansion of signal transmission within mobiles such as aircraft, satellites and even ships. • Signal Security: – The light from optical fibers does not radiate significantly and therefore they provide a high degree of signal security.
Unlike the situation with copper cables, a transmitted optical signal cannot be obtained from a fiber in a noninvasive manner (i. e. without drawing optical power from the fiber). Therefore, in theory, any attempt to acquire a message signal transmitted optically may be detected. This feature is obviously attractive for military, banking and general data transmission (i. e. computer network) application. • Ruggedness and Flexibility:- Although protective coatings are essential, optical fibers may be manufactured with very high tensile strengths.
Perhaps surprisingly for a glassy substance, the fibers may also be bent to quite small radii or twisted without damage. Furthermore cable structures have been developed which have proved flexible, compact and extremely rugged. Taking the size and weight advantage into account, these optical fiber cables are generally superior in terms of storage, transportation, handling and installation to corresponding copper cables, whilst exhibiting at least comparable strength and durability. • System Reliability And Ease Of Maintenance :- These features primarily stem from the low loss property of optical fiber cables which reduces the equirement for intermediate repeaters or line amplifiers to boost the transmitted signal strength. Hence with fewer repeaters, system furthermore, the reliability of the optical components is no longer a problem with predicted lifetimes of 20 to 30 years now quite common. Both these factors also tend to reduce maintenance time and costs. • Enormous Potential Bandwidth: – The optical carrier frequency in the range 1013 to 1016 Hz (generally in the near infrared around 1014 Hz or 105 GHz) yields a far greater potential transmission bandwidth than metallic cable systems. i. e. coaxial cable bandwidth up to around 500 MHz) or even millimetre wave radio systems (i. e. systems currently operating with modulation bandwidths of 700 MHz ). At present, the bandwidth available to fiber systems is not fully utilized but modulation at several gigahertz over a hundred kilometers and hundreds of megahertz over three hundred kilometers without intervening electronics (repeaters) is possible. Therefore, the information – carrying capacity of optical fiber systems has proved far superior to the best copper cable systems. Wireless Line: * Bluetooth:
Bluetooth is a standard and communications protocol primarily designed for low power consumption, with a short range (power-class-dependent: 1 meter, 10 meters, 100 meters) based on low-cost transceiver microchips in each device. Bluetooth enables these devices to communicate with each other when they are in range. The devices use a radio communications system, so they do not have to be in line of sight of each other, and can even be in other rooms, as long as the received transmission is powerful enough. Bluetooth exists in many products, such as telephones, printers, modems and headsets.
The technology is useful when transferring information between two or more devices that are near each other in low-bandwidth situations. Bluetooth is commonly used to transfer sound data with telephones (i. e. with a Bluetooth headset) or byte data with hand-held computers (transferring files). Bluetooth protocols simplify the discovery and setup of services between devices. Any Bluetooth device can, in theory, host any other Bluetooth device. This makes using services easier because there is no longer a need to set up network addresses or permissions as in many other network.
More prevalent applications of Bluetooth include: Wireless control of and communication between a mobile phone and a hands-free headset. This was one of the earliest applications to become popular. Wireless networking between PCs in a confined space and where little bandwidth is required. Wireless communications with PC input and output devices, the most common being the mouse, keyboard and printer. Replacement of traditional wired serial communications in test equipment, GPS receivers, medical equipment, bar code scanners, and traffic control devices.
For controls where infrared was traditionally used. Sending small advertisements from Bluetooth enabled advertising hoardings to other, discoverable, Bluetooth devices. Future of Bluetooth: * Broadcast Channel: enables Bluetooth information points. This will drive the adoption of Bluetooth into mobile phones, and enable advertising models based around users pulling information from the information points, and not based around the object push model that is used in a limited way today. Topology Management: enables the automatic configuration of the piconet topologies especially in scatternet situations that are becoming more common today. This should all be invisible to the users of the technology, while also making the technology just work. * Alternate MAC PHY: enables the use of alternative MAC and PHY’s for transporting Bluetooth profile data. The Bluetooth Radio will still be used for device discovery, initial connection and profile configuration, however when lots of data needs to be sent, the high speed alternate MAC PHY’s will be used to transport the data.
This means that the proven low power connection models of Bluetooth are used when the system is idle, and the low power per bit radios are used when lots of data needs to be sent. * QoS improvements: enable audio and video data to be transmitted at a higher quality, especially when best effort traffic is being transmitted in the same piconet. Figure: -A typical Bluetooth USB dongle * 3-G Mobile: 2. 54 & 3 G falls into the category of broadband access. 2. 5G- GSM (EDGE/GPRS), CDMA 3G-VMTS/WCDMA, CDMA, speed achieved by 3G is 384K(M),2048K(S) Technology| 3G|
Frequency Band| 1. 8-2. 5 GHz| Bandwidth| 5-20 MHz| Data Rate| Up-to 2 Mbps| Access| W-CDMA| FEC| Turbo-Codes| Switching| Cirsuit/Packet| Figure: -3G Services * Wi-Fi: A Wi-Fi enabled device such as a PC, game console, cell phone, MP3 player or PDA can connect to the Internet when within range of a wireless network connected to the Internet. The coverage of one or more interconnected access points — called a hotspot — can comprise an area as small as a single room with wireless-opaque walls or as large as many square miles covered by overlapping access points.
Wi-Fi technology has served to set up mesh networks, for example, in London. Both architectures can operate in community networks. In addition to restricted use in homes and offices, Wi-Fi can make access publicly available at Wi-Fi hotspots provided either free of charge or to subscribers to various providers. Wi-Fi also allows connectivity in peer-to-peer (wireless ad-hoc network) mode, which enables devices to connect directly with each other. This connectivity mode can prove useful in consumer electronics and gaming applications. Figure : -A keychain size Wi-Fi detector.
Operational advantages: Wi-Fi allows LANs (Local Area Networks) to be deployed without cabling for client devices, typically reducing the costs of network deployment and expansion. Spaces where cables cannot be run, such as outdoor areas and historical buildings, can host wireless LANs. * WiMAX WiMAX, an approximate acronym of Worldwide Interoperability for Microwave Access, is a telecommunications technology that provides for the wireless transmission of data using a variety of transmission modes, from point-to-point links to full mobile cellular-type access.
The technology provides upto 70 Mb/sec symmetric broadband speed without the need for cables. The technology is based on the IEEE 802. 16 standard (also called WirelessMAN). The name “WiMAX” was created by the WiMAX Forum, which was formed in June 2001 to promote conformity and interoperability of the standard. Uses: The bandwidth and range of WiMAX make it suitable for the following potential applications: * Connecting Wi-Fi hotspots to the Internet. * Providing a wireless alternative to cable and DSL for “last mile” broadband access. * Providing data and telecommunications services. Providing a source of Internet connectivity as part of a business continuity plan. That is, if a business has a fixed and a wireless Internet connection, especially from unrelated providers, they are unlikely to be affected by the same service outage. * Providing portable connectivity. Comparison with Wi-Fi: Comparisons and confusion between WiMAX and Wi-Fi are frequent, possibly because both begin with the same two letters, are based upon IEEE standards beginning with “802. “, and are related to wireless connectivity and Internet access. However, the two standards are aimed at different applications. WiMAX is a long-range system, covering many miles/kilometers that typically uses licensed spectrum (although it is possible to use unlicensed spectrum) to deliver a point-to-point connection to the Internet from an ISP to an end user. Different 802. 16 standards provide different types of access, from mobile (similar to a cellphone) to fixed (an alternative to wired access, where the end user’s wireless termination point is fixed in location. ) * Wi-Fi is generally a shorter range system, typically tens of yards/meters, though its range can be extended to over a kilometer using directional antennas.
Wi-Fi uses unlicensed spectrum to provide access to a network. Typically Wi-Fi is used by an end user to access his/her own network, which may or may not be connected to the Internet. If WiMAX provides services analogous to a cellphone, Wi-Fi is similar to a cordless phone. * WiMAX and Wi-Fi have quite different Quality of Service (QoS) mechanisms. WiMAX uses a mechanism based on connections between the Base Station and the user device. Each connection is based on specific scheduling algorithms, which means that QoS parameters can be guaranteed for each flow.
Wi-Fi has introduced a QoS mechanism similar to fixed Ethernet, where packets can receive different priorities based on their tags. This means that QoS is relative between packets/flows, as opposed to guaranteed. * WiMAX is highly scalable from what are called “femto”-scale remote stations to multi-sector ‘maxi’ scale base that handle complex tasks of management and mobile handoff functions and include MIMO-AAS smart antenna subsystems. * LMDS: Local Multipoint Distribution Services (LMDS) is a radio-based access system.
A fixed base-antenna (typically on a high building or tower) called Hub, services a number of users, which are also fixed. (Customer antenna on top of building). The access has a broadband capacity it can be used for all kinds of telecom services: – * POTS or ISDN telephony. * Data services such as LAN interconnect, ATM, IP networks, etc. * Digital Video broadcasting. And potential customers are: – * Businesses * Schools, Libraries, Health care providers * Residential consumers Each Hub is at the center of cell, a few kilometers in size, containing hundreds or thousands of users.
Interconnections between hubs are typically done through fiber-optic core networks. The radio frequencies used are in the range 28 GHz to 42 GHz. This requires ‘line-of-sight’ between hub and end-user. The word Local in LMDS refers to the relative short distance, or small cell-size. The words Multipoint Distribution refers to the point to multipoint nature. Figure 36: – Local Multipoint Distribution Services * Free Space Optics (FSO): It is optical wireless, point-to-point line of sight broadband technology that is an alternative to fiber optic cable systems.
It can transmit up to 1. 25 Gbps at a distance of 4 miles. * Satellite: It offers two-way Internet access via satellite orbiting the earth about 22000 miles above equator. PC through a special satellite modem broadcasts the requests to the satellite dish located on top of the roof / building which in turn transmits & receives signal from the satellites. But it is slower in uplink as well as in downlink. BIBLIOGRAPHY (1) www. bsnl. co. in (2) www. wikipedia. org (3) www. howstuffworks. com (4) www. esnips. com