The first commercial telephone services were set up in 1878 and 1879 on both sides of the Atlantic. Till the generation of copper wire, every call had to have a dedicated wire stretching from one end of the call to the other for the duration of the call. The call had to connected through switches between pieces of copper wire. Now voice is digitized, and thousands of calls can be combined onto a single fiber optic cable. These calls are transmitted at a fixed rate of 64 kilobits per second (Kbps) in each direction, for a total transmission rate of 128 Kbps.

A packet-switched phone network is the alternative to circuit switching. Data networks simply send and retrieve data as you need it. And, instead of routing the data over a dedicated line, the data packets flow through a network along thousands of possible paths. This is called packet switching.  It lets the network route the packets along the least congested and cheapest lines. It also frees up the two computers communicating with each other so that they can accept information from other computers, as well.

RADIO SPECTRUM

Mobile operators use radio spectrum to provide the services. Before the advent of cellular technology, capacity was enhanced through a division of frequencies, and the resulting addition of available channels. However, this reduced the total bandwidth available to each user, affecting the quality of service.

Cellular technology allowed for the division of geographical areas, rather than frequencies, leading to a more efficient use of the radio spectrum. This geographical re-use of radio channels is known as “frequency reuse”.

In a cellular network, cells are generally organized in groups of seven to form a cluster. There is a “cell site” or “base station” at the centre of each cell, which houses the transmitter/receiver antennae and switching equipment.

The size of a cell depends on the density of subscribers in an area: for instance, in a densely populated area, the capacity of the network can be improved by reducing the size of a cell or by adding more overlapping cells. This increases the number of channels available without increasing the actual number of frequencies being used. All base stations of each cell are connected to a central point, called the Mobile Switching Office (MSO), either by fixed lines or microwave.

The MSO is generally connected to the PSTN (Public Switched Telephone Network).

Cellular technology allows the “hand off” of subscribers from one cell to another as they travel around. This is the key feature which allows the mobility of users.

A computer constantly tracks mobile subscribers of units within a cell, and when a user reaches the border of a call, the computer automatically hands-off the call and the call is assigned a new channel in a different cell.

International roaming arrangements govern the subscriber’s ability to make and receive calls the home network’s coverage area.

Fibre-Optics is the Branch of science which deals with transfer of information from one point to another using fibres is called fibre optics. It uses s lights wave as carrier waves of signals. It is based on the principle of total Internal reflection.Optical fibreis a thin, cylindrical cable made of glass fibre used for transmitting light signals. Light is propagated down an optical fibre by refraction and internal reflection. The Core has high refractive index.Cladding has less refractive index in comparison to core.

There are two types of fibres, one in which the central core has uniform refractive index (Step Index) and the other where there is a gradual change in the refractive index(Graded Index) decreasing outward from the centre of the fibre.

Before they are sent through an optical fibre, electrical signals are converted into pulses of light by semiconductor devices known as light emitting diode (LED) and laser diode.

At the far end, light is reconverted into electrical signals by a receiver which consists of a photodiode. Signals can be transmitted in both directions provided that both ends of the fibre have a source and a receiver.

The main advantages of optical fibres in transmission of information are its larger channel capacity, lighter weight compared to copper cables and no possibility of a cross talk between adjacent cables. Besides, these cables do not pick up any noise signals and can withstand extreme environmental conditions. Thus it has no Interference from outer environment.  They are even cheaper than copper cables.They have lesser signal loss and large signal carrying capacity

Mobile satellite telecommunications is being pioneered by the International Maritime Satellite Communication Organization (Immarsat), the global mobile satellite communication organization. Inmarsat is an intergovernmental organization having 76 member nations, headquartered in London. It was set up in 1979 to serve the maritime community, but has now expanded into being the sole provider of world wide mobile satellite communications for commercial and distress and safety applications at sea, on land and in the air. India is a founder member of Immarsat. Videsh Sanchar Nigam is the signatory to Immarsat on behalf of the government of India. Immarsat is able to support service including direct dial telephone, telex, facsimile, electronic mail and data communications between mobile users and subscribers around the world connected to the International Public Switched Network.

The three essential components of this system are:

• The Inmarsat Space segment, comprising satellites and associated ground support facilities.
• The Land Earth Station (LES) which provides an interface between the space segment and the nationally and internationally fixed telecommunications networks.
• The Mobile Earth Station (MES), the satellite communication terminals located on ships, trucks etc.

Hand-held satellite telephone - Inmarsat-P: The advent of the hand-held satellite telephone Immarsat-P will be the realization of one of mankind’s ultimate dreams - the ability to communicate instantly and effortlessly to and from any place on Earth. A new generation of advanced satellites will be required to deliver Immarsat-P services. The complex issues encompassing the choice of available satellite technology have led Inmarsat to decide and focus on two of the most promising designs - intermediate circular orbit (ICO) and geostationary orbit (GSO). The choice of spacecraft constellation will be ultimately the quality and price of any service. Mobile satellite communications is likely to be one of the most exciting areas to be watched in the realm of communications.

Multimedia 

Multimedia is now the latest buzzword in this era of information revolution multimedia means digitizing information from various sources like text, audio, video, music etc., and recording it on a computer system where it can be manipulated and recombined.

It is in other words an interactive television system. The invention of the laser disc and personal computer gave rise to the concept of multimedia. One is used to control the other and images and texts are interspersed to create new issues and stories. CD-ROMs (compact disc read only memories) are the building blocks of multimedia.

Virtual reality is the most talked about aspect of multimedia. This latest technique uses the modeling capabilities of the computer to create a digital world which can be seen and touched. A small pair of LCD (Liquid Crystal display) screen in front of the viewer facilitates viewing.

The images supplied by the computer when viewed through the LDC gives rise to a three dimensional view. Multimedia is usually of two types ‘non interactive’ and ‘interactive’ Corporate presentations done in multimedia and presented to an audience are usually non interactive. Here the audience is rather passive in the sense that they simply receive the information presented to them in the form of video, sound images, text, animations etc. Interactive multimedia on the other hand is oriented specifically to the individual use. Here the user is the master. He can choose precisely what he wants to know and move from one point in the environment to another through a process called ‘navigation’.

Video conferencing

Another significant breakthrough of the breathtaking developments in information technology is video conferencing A video conferencing is a sort of two-way video communication between two or more places to meet and discuss issues and strategies in a particular time.

It is almost similar to a round table conference except for that, in this case the round table is a television/computer screen. Video conferencing is usually used by large multinationals to confer with their branch offices or government agencies or corporations. Also, a number of educational institutions are using video conferencing for teaching and research. Video conferencing reduces business travel and improves productivity through faster and better decision making. It helps the company to get closer to the customer and reduces the lead time for the development of new products.

VSAT

VSAT (Very Small Aperture Terminal) is a satellite communications system that serves home and business users. A VSAT end user needs a box that interfaces between the user's computer and an outside antenna with a transceiver. The transceiver receives or sends a signal to a satellite transponder in the sky. The satellite sends and receives signals from an earth station computer that acts as a hub for the system. Each end user is interconnected with the hub station via the satellite in a star topology. For one end user to communicate with another, each transmission has to first go to the hub station which retransmits it via the satellite to the other end user's VSAT. VSAT handles data, voice, and video signals.

VSAT is used both by home users who sign up with a large service such as DirecPC and by private companies that operate or lease their own VSAT systems. VSAT offers a number of advantages over terrestrial alternatives. For private applications, companies can have total control of their own communication system without dependence on other companies. Business and home users also get higher speed reception than if using ordinary telephone service or ISDN.

WiMAX

The main problems with broadband access are that it is pretty expensive and it doesn't reach all areas. The main problem with WiFi access is that hot spots are very small, so coverage is sparse.WiMAX (Worldwide Interoperability for Microwave Access) is a wireless communications standard designed to provide 30 to 40 megabit-per-second data rates. This new technology would provide:

• The high speed of broadband service
• Wireless rather than wired access, so it would be a lot less expensive than cable or DSL and much easier to extend to suburban and rural areas
• Broad coverage like the cell phone network instead of small WiFi hotspots

WiMAX equipment exists in two basic forms - base stations, installed by service providers to deploy the technology in a coverage area, and receivers, installed in clients. WiMAX supports several networking usage models.

LiFi

It is a wireless optical networking technology that uses light-emitting diodes (LEDs) for data transmission. LiFi is designed to use LED light bulbs similar to those currently in use in many energy-conscious homes and offices. However, LiFi bulbs are outfitted with a chip that modulates the light imperceptibly for optical data transmission. LiFi data is transmitted by the LED bulbs and received by photoreceptors. LiFi's early developmental models were capable of 150 megabits-per-second (Mbps). Some commercial kits enabling that speed have been released. In the lab, with stronger LEDs and different technology, researchers have enabled 10 gigabits-per-second (Gbps), which is faster than 802.11ad.

Benefits of LiFi:

i) Higher speeds than Wi-Fi.

ii) 10000 times the frequency spectrum of radio.

iii)More secure because data cannot be intercepted without a clear line of sight.

iv) Prevents piggybacking.

v) Eliminates neighboring network interference.

vi) Unimpeded by radio interference.

vii) Does not create interference in sensitive electronics, making it better for use in environments like hospitals and aircraft.

By using LiFi in all the lights in and around a building, the technology could enable greater area of coverage than a single WiFi router. Drawbacks to the technology include the need for a clear line of sight, difficulties with mobility and the requirement that lights stay on for operation.

CAS 

Conditional access system, CAS is an addressability system required for viewing the desired pay channels by the subscribers.  It would enable the subscriber to pay only for those channels that he or she wishes to watch.  It will also bring transparency in the system, since accurate figures of subscriber base would be available.  Therefore, the broadcasters cannot complain of under reportage of subscriber base, for arbitrary hikes in the rates of pay channels. 

ACCESS TECHNOLOGIES (FDMA, TDMA, CDMA)

FDMA: Frequency Division Multiple Access is a technique whereby spectrum is divided up into frequencies and then assigned to users. With FDMA, only one subscriber at any given time is assigned to a channel. The channel is therefore is closed to other conversations until the initial call is finished, or until it is handed-off to a transmitting and the other for receiving. FDMA has been used for first generation analog systems.

TDMA: Time Division Multiple Access  improves spectrum capacity by splitting each frequency into slots. TDMA allows each user to access the entire radio frequency channel for the short period of a call. Other users share this same frequency channel at different time slots. The base station continually switches from user to user on the channel. TDMA is the dominant technology for the second generation mobile cellular networks.

CDMA: Code Division Multiple Access is based on “spread” spectrum technology.

CDMA increases spectrum capacity by allowing all users to occupy all channels at the same time. Transmissions are spread over the whole radio band, and each voice or data call are assigned a unique code to differentiate from the other calls carried over the same spectrum. CDMA allows for a “soft hand-off”, which means that terminals can communicate with several base stations at the same time. The dominant radio interface for third-generation mobile, or IMT-2000, will be a wideband version of CDMA with three models (IMT-DS, IMT-MC and IMT-TC).

GSM

GSM, which stands for Global System for Mobile communications, reigns as the world’s most widely used cell phone technology. Cell phones use a cell phone service carrier’s GSM network by searching for cell phone towers in the nearby area.

The origins of GSM can be traced back to 1982 when the Groupe Spécial Mobile (GSM) was created by the European Conference of Postal and Telecommunications Administrations (CEPT) for the purpose of designing a pan-European mobile technology.

It is approximated that 80 percent of the world uses GSM technology when placing wireless calls, according to the GSM Association (GSMA), which represents the interests of the worldwide mobile communications industry. This amounts to nearly 3 billion global people.

AT A GLANCE

• Advantage: Its large user base is its biggest advantage.  This and the roaming facility it allows, give it an edge.  Besides, GSM uses SIM cards, while in CDMA the entire handset has a number. 
• Disadvantages: CDMA has higher ‘throughput’ meaning it can transmit data more cost-efficiently.

GENERATIONS IN TELECOMMUNICATIONS

The first wireless mobile telecommunications technologies are referred to as 1G which originated in the 1980s. They were predominantly analog and provided only voice services.

2G refers to the second generation of mobile telecommunications technologies. The most well known 2G technology is GSM. The first CDMA standard (cdmaOne) was also a 2G technology. Being digital, 2G technologies not only provide voice services, they can also provide data transfer by Short Messaging Service. 2G technologies also provide greater security to the users as the communications are encrypted.

There are certain intermediate technologies between 2G and 3G that are referred to as 2.5G and 2.75G. The main intermediate technologies are GPRS and EDGE. Both provide high speed data transfer on existing 2G networks enabling Internet access on mobile phones.

GPRS: General Packet Radio Service (GPRS) is a mobile data service available to all users of GSM technology. GPRS provides data rates of 56-114 kbps. It enables use of Internet on mobile phones, and multimedia messaging service (MMS.)

EDGE: Stands for ‘Enhanced Data rates for GSM Evolution’. Also known as Enhanced GPRS or EGPRS. It is a mobile data service available to all users of GSM technology. It is considered a 3G technology. It is more sophisticated than the earlier GPRS and provides more than three-fold increase in both the capacity and performance of GPRS. It can provide data rates of upto 384 kbps, allowing Internet access at higher speeds. The existing GSM infrastructure is not required to be changed.

3G STANDARDS: The two main 3G standards are:

UMTS: Universal Mobile Telecommunications Service. It is an evolution of the 2G GSM standard. It was introduced in 2001. It is used primarily in Europe, Japan, China and other regions predominated by GSM 2G system infrastructure. This is the technology that is currently in use by BSNL and MTNL for their 3G services.

CDMA 2000: It was introduced in 2002. It is used mainly in North America and South Korea and other regions predominated by CDMA (cdmaOne) infrastructure.

FEATURES OF 3G:

Provides voice, SMS and data transfer at speeds much higher than GRPS and EDGE, enabling users to access Internet at broadband speeds, on mobile phones. The most well known 3G feature is video telephony i.e. simultaneous voice and non-voice data transfer. From development point of view 3G can: be great booster in areas such as Telemedicine, Mobile Banking, inclusive banking such as taking banking and financial services to remote villages, help provide weather updates and market price information to farmers, it can provide TV and entertainment services for remote ' villages. It can also be used in disaster management, as a cheap and effective means d coordinating rescue and relief efforts with the use of live images.

4G 4G Technology is basically the extension in the 3G technology with more bandwidth and services offers in the 3G. 4G technology is one that satisfies the requirements of the IMT-Advanced (International Mobile Telecommunications Advanced) standard, as defined by the International Telecommunications Union (ITU.) According to the ITU, an IMT-Advanced cellular system must have data transfer speeds of up to approximately 100 Mbps for mobile users and up to approximately 1 Gbps for fixed users. A 4G system is expected to provide facilities such as IP telephony, ultra-broadband Internet access, gaming services and streamed multimedia, and even HDTV (high definition TV.)

The main objective of this generation is to converge all the technologies into one another with simplified structure, any user can use his respective services even on the phone line, and similarly he can use his broadband services on mobile. In short you may say that any network can be accessed on any terminal. The main technologies of 4G are LTE (Long Term Evolution), WiMax (Worldwide Interoperability for Microwave Access), UMB (Ultra Mobile Broadband) and EV-DO (Rev. C). The advantage of this Generation is that they can also communicate with 3G technologies and also even with GSM Phase 2+

Aircel and Bharati Airtel are offering these services in India.

Mobile Operating Systems

Symbian is an operating system (OS) and software platform designed for smartphones and was maintained by Nokia. Symbian OS was originally developed by Symbian Ltd.

Windows Phone is a mobile operating system developed by Microsoft, and is the successor to its Windows Mobile platform, although incompatible with it.  With Windows Phone, Microsoft offers a new user interface with its design language, Metro, integrates the operating system with third party and other Microsoft services, and controls the hardware on which it runs

Android is a Linux-based operating system for mobile devices such as smartphones and tablet computers. It is developed by the Open Handset Alliance led by Google. It has the largest installed base worldwide on smartphones. The current Android version is 4.4.

Open Handset Alliance is, a consortium of 86 hardware, software, and telecommunication companies devoted to advancing open standards for mobile devices. The Android Open Source Project (AOSP) is tasked with the maintenance and further development of Android.

Android has a large community of developers writing applications ("apps") that extend the functionality of the devices. Developers write primarily in a customized version of Java. Apps can be downloaded from third-party sites or through online stores such as Android Market, the app store run by Google.

The latest version[1] of Android are Jelly Bean (4.1), (4.2), (4.3) and Kit Kat (4.4), Lollipop (5.0-5.1.1) and Marshmallow (6.0–6.0.1)

Mobile Applications

It is a term used to describe Internet applications that run on smartphones and other mobile devices. Mobile applications usually help users by connecting them to Internet services more commonly accessed on desktop or notebook computers, or help them by making it easier to use the Internet on their portable devices. A mobile app may be a mobile Web site bookmarking utility, a mobile-based instant messaging client, Gmail for mobile, and many other applications.

GPS on mobile phones: Assisted GPS

"Standalone" or "Autonomous" GPS operation uses radio signals from satellites alone. A-GPS additionally uses network resources to locate and utilize the satellites in poor signal conditions. In very poor signal conditions, for example in a city, these signals may suffer multipath propagation where signals bounce off buildings, or be weakened by passing through atmospheric conditions, walls or tree cover. When first turned on in these conditions, some standalone GPS navigation devices may not be able to work out a position due to the fragmentary signal, rendering them unable to function until a clear signal can be received continuously for up to 12.5 minutes (the time needed to download the GPS almanac and ephemeris)

In AGPS, the Network Operator deploys an AGPS server. These AGPS servers download the orbital information from the satellite and store it in the database. An AGPS capable device can connect to these servers and download this information using Mobile Network radio bearers such as GSM, CDMA, WCDMA, LTE or even using other wireless radio bearers such as Wi-Fi. Usually the data rate of these bearers is high, hence downloading orbital information takes less time.

Though not a true GPS, AGPS is widely used on application like Map and Location services on mobile phones.

AGPS has two modes of operation:

Mobile Station Assisted (MSA) - In MSA mode A-GPS operation, the A-GPS capable device receives acquisition assistance, reference time and other optional assistance data from the A-GPS server. With the help of the above data, the A-GPS device receives signals from the visible satellites and sends the measurements to the A-GPS server. The A-GPS server calculates the position and sends it back to the A-GPS device.

Mobile Station Based (MSB) - In MSB mode A-GPS operation, the A-GPS device receives ephemeris, reference location, reference time and other optional assistance data from the A-GPS server. With the help of the above data, the A-GPS device receives signals from the visible satellites and calculates the position

environmental conditions. They are even cheaper than copper cables.

DTH

Direct to Home (DTH) broadcasting is the technology that allows people to receive television programmes in the Ku Satellite transmission band in their homes, directly via small dish antenna. In Traditional method television programme is send out from terrestrial transmitter and received with small & cheap half wave dipole antennas LPT (Low power transmitter) is used. In satellite based television services local cable operator receive prog (channels) using 1 or more 3-4 m dIa antennas and send them to individual homes using coaxial cable. C. Band (3.4 - 6.65 GHz) is used for transmission.

Advantages of DTH system

• This makes it suitable for home users even in remote areas, where conventional cable networks are not in place.
• Size of antennas required is just 35-40 cm dia [1.5-4m dia antennas-C band] They are very light & can be placed anywhere
• A lot of channels are provided (over 100)
• It’s transmission is superior in quality and not subject to vagaries of cable
• The introduction of DTH services would provide a window for broadcasting companies to migrate to providing more interactive services in video, audio and text on such platforms.
• Significantly, it would also provides new media companies with the ideal platform to provide integrated and interactive broadband services.

India on 2nd November 2000 permitted the introduction of Direct-to-Home services in the country.

Conditions

• The Centre has opened the doors to DTH, with no cap on the number of players to provide this service.
• But there are curbs on foreign equity, particularly foreign direct investment.
• Also, the Centre has laid down certain conditions-it must be under Indian management, with not more than 49 per cent foreign equity of which only 20 per cent can be FDI.
• The earth station must be set up on Indian soil to ensure than up linking is from India and so under content regulation.
• The domestic advertisement and programming code will apply to DTH as well. It cannot carry channels prohibited by the Information Ministry and should show all the Prasar Bharti channels on most favoured terms.
• Though the broadcaster would be free to use a satellite of his choice, proposals involv­ing the use of Indian satellite capacity would be given prefer­ence in the grant of licenses.

The technology of DTH ensures highest quality of voice, video as it uses digital form of communication system. The DTH service also provides various value added services such as internet services, telemedicine, video conferencing etc. Since in DTH technology, all the encoded transmission signals are digital.Thus, it provides higher resolution picture quality and better audio than traditional analog signals. In recent years DTH has become the buzzword in the satellite broadcasting industry because of immense opportunities it offers to broadcasters and viewers.

E-mail

E-mail is the short form for electronic mail, which is based on the use of computers for the transmission of massages rather than through the postal system.

The e-mail system connects a network of personal computers (PC) spread over hundreds of locations within a country or across the globe.

The main advantages of e-mail are that it cuts down the delay involved in postal transmission of messages. Moreover, messages can be sent at any time of day or night which are shored and can be retrieved by the recipient at his or her convenience. Besides once the contact between the transmitter and receiver PCs is established e-mail requires only a few minutes time to transmit even a bulky message.

Compared to fax, E-mail is error-free whereas as fax is not. And lastly, E-mail works out to be much cheaper as compared to fax.

A computer network, often simply referred to as a network, is a collection of computers and other hardware components interconnected by communication channels that allow sharing of resources and information. Where at least one process in one device is able to send/receive data to/from at least one process residing in a remote device, then the two devices are said to be in a network. Simply, more than one computer interconnected through a communication medium for information interchange is called a computer network.

Networks may be classified according to a wide variety of characteristics, such as the medium used to transport the data, communications protocol used, scale, topology, and organizational scope.

Communications protocols define the rules and data formats for exchanging information in a computer network, and provide the basis for network programming. Well-known communications protocols include Ethernet, hardware and link layer standard that is ubiquitous in local area networks, and the Internet protocol suite, which defines a set of protocols for internetworking, i.e. for data communication between multiple networks, as well as host-to-host data transfer, and application-specific data transmission formats.

Properties of Computer networks:

Facilitate communications

• Using a network, people can communicate efficiently and easily via email, instant messaging, chat rooms, telephone, video telephone calls, and video conferencing.
• Permit sharing of files, data, and other types of information
• In a network environment, authorized users may access data and information stored on other computers on the network. The capability of providing access to data and information on shared storage devices is an important feature of many networks.

Share network and computing resources

• In a networked environment, each computer on a network may access and use resources provided by devices on the network, such as printing a document on a shared network printer. Distributed computing uses computing resources across a network to accomplish tasks.

May be insecure

• A computer network may be used by computer hackers to deploy computer viruses or computer worms on devices connected to the network, or to prevent these devices from normally accessing the network (denial of service).

May interfere with other technologies

• Power line communication strongly disturbs certain forms of radio communication, e.g., amateur radio. It may also interfere with last mile access technologies such as ADSL and VDSL.

May be difficult to set up

• A complex computer network may be difficult to set up. It may also be very costly to set up an effective computer network in a large organization or company.

Communication media

Computer networks can be classified according to the hardware and associated software technology that is used to interconnect the individual devices in the network, such as electrical cable (HomePNA, power line communication, G.hn), optical fiber, and radio waves (wireless LAN). In the OSI model, these are located at levels 1 and 2.

A well-known family of communication media is collectively known as Ethernet. It is defined by IEEE 802 and utilizes various standards and media that enable communication between devices. Wireless LAN technology is designed to connect devices without wiring. These devices use radio waves or infrared signals as a transmission medium.

Wired technologies

The order of the following wired technologies is, roughly, from slowest to fastest transmission speed.

Twisted pair wire is the most widely used medium for telecommunication. Twisted-pair cabling consist of copper wires that are twisted into pairs. Ordinary telephone wires consist of two insulated copper wires twisted into pairs. Computer networking cabling (wired Ethernet as defined by IEEE 802.3) consists of 4 pairs of copper cabling that can be utilized for both voice and data transmission. The use of two wires twisted together helps to reduce crosstalk and electromagnetic induction. The transmission speed ranges from 2 million bits per second to 10 billion bits per second. Twisted pair cabling comes in two forms: unshielded twisted pair (UTP) and shielded twisted-pair (STP). Each form comes in several category ratings, designed for use in various scenarios.

Coaxial cable is widely used for cable television systems, office buildings, and other work-sites for local area networks. The cables consist of copper or aluminum wire surrounded by an insulating layer (typically a flexible material with a high dielectric constant), which itself is surrounded by a conductive layer. The insulation helps minimize interference and distortion. Transmission speed ranges from 200 million bits per second to more than 500 million bits per second.

ITU-T G.hn technology uses existing home wiring (coaxial cable, phone lines and power lines) to create a high-speed (up to 1 Gigabit/s) local area network.

Wireless technologies

Terrestrial microwave – Terrestrial microwave communication uses Earth-based transmitters and receivers resembling satellite dishes. Terrestrial microwaves are in the low-gigahertz range, which limits all communications to line-of-sight. Relay stations are spaced approximately 48 km (30 mi) apart.

Communications satellites – The satellites communicate via microwave radio waves, which are not deflected by the Earth's atmosphere. The satellites are stationed in space, typically in geosynchronous orbit 35,400 km (22,000 mi) above the equator. These Earth-orbiting systems are capable of receiving and relaying voice, data, and TV signals.

Cellular and PCS systems use several radio communications technologies. The systems divide the region covered into multiple geographic areas. Each area has a low-power transmitter or radio relay antenna device to relay calls from one area to the next area.

Radio and spread spectrum technologies – Wireless local area network use a high-frequency radio technology similar to digital cellular and a low-frequency radio technology. Wireless LANs use spread spectrum technology to enable communication between multiple devices in a limited area. IEEE 802.11 defines a common flavor of open-standards wireless radio-wave technology.

Infrared communication can transmit signals for small distances, typically no more than 10 meters. In most cases, line-of-sight propagation is used, which limits the physical positioning of communicating devices.

A global area network (GAN) is a network used for supporting mobile across an arbitrary number of wireless LANs, satellite coverage areas, etc. The key challenge in mobile communications is handing off user communications from one local coverage area to the next. In IEEE Project 802, this involves a succession of terrestrial wireless LANs.

Exotic technologies

There have been various attempts at transporting data over more or less exotic media:

• IP over Avian Carriers was a humorous April fool's Request for Comments, issued as RFC 1149. It was implemented in real life in 2001.
• Extending the Internet to interplanetary dimensions via radio waves.
• Both cases have a large round-trip delay time, which prevents useful communication.

LAN

Lan is the short form of Local Area Network. It allows the linking together of several computers within a building. This interconnection of various computer terminals located in close proximity such as an industrial complex, an office building and a university campus enables each terminal to interact with any other. LAN is, therefore, a multi-user system. Not only is the exchange of data among the various linked up computers made possible by LAN but resources from a large computer can also be shared. LAN thus offers the most effective means of handling local automated tasks and data management.

LAN can be even linked with an outside computer network using 'gateway'. The gateway converts the formats of data to make them compatible to the two networks.

Internet

Internet is the abbreviation of Internetwork System and is described as a network of networks. Internet is the most important information networks available in the world. Internet is a worldwide computer network that contains a large collection of information which could be made available to you on your computer. The largest and most complete learning tool for a group of people with varied educational backgrounds and interests.

Application

• Professors, students and other educators can share ideas instantly across vast distances.
• Through internet, scientists can gain instant access to the world’s most advanced research facilities and discuss their research problems with others, working in the same field.
• For business community, Internet is the common place where they can discuss and set the business  deals without moving from their place.
• The persons who want to procure something, places his requirement on internet and the concerned supplier(s) can quote for the same, almost instantly.
• It also serves as an encyclopedia since one can get the desired information, in detail, on any subject of his interest.

Net Neutrality

What is Net Neutrality:

Net neutrality is the principle that internet providers treat all web traffic equally, and it’s pretty much how the internet has worked since its creation. But regulators, consumer advocates and internet companies were concerned about what broadband companies could do with    their power as the pathway to the internet — blocking or slowing down apps that rival their own services.

What did the government do about it?

India’s Internet will be governed by the rules of net neutrality as the Telecom Commission has accepted the recommendations made by regulatory body TRAI (Telecom Regulatory Association of India).

According to TRAI’s Net Neutrality rules, first recommended back in November 2017, discriminatory treatment of content is prohibited. What this means is that the ISP or internet providers cannot charge extra for say watching videos on Netflix at a high-speed. The rules bar ISPs from creating high-speed data lanes, or charging extra for viewing certain kind of content on the web.

It also means that zero-rating packages like says a Facebook Free Basics, where certain content is provided for free like access to Facebook, also remain illegal in India. The recommendations had also noted, “the use of Internet should be facilitated in such a manner that it advances the free speech rights of citizens, by ensuring plurality and diversity of views, opinions, and ideas.”

What is out of purview of Net Neutrality?

Telecom Commission has kept some critical applications or services like remote surgery and autonomous cars out of the purview of this framework. TRAI in its recommendations had also kept CDN or content delivery networks out of the purview of Net Neutrality.

CDNs allow a telecom company to deliver content on their network, without accessing public internet. Players like Airtel, Reliance Jio are doing this. In order to access the content provided by them, the user has be on the respective network.

The regulator had also recommended restrictions on service providers from entering into agreements which lead to discriminatory treatment of content on the Internet. When it comes to Internet of Things (IoT), ) TRAI said it “should not be specifically excluded from the scope of the restrictions on nondiscriminatory treatment.”

Specialised services are only exempt from Net Neutrality rules if “such services are not usable or offered as a replacement for Internet Access Services.”  Still, the recommendations from TRAI also allow for “reasonable traffic management practices and certain other legitimate purposes” provided they are transparent interventions.

Any violation of the core principles of net neutrality would involve a two-stage process of review and appeal. TRAI would also continue to regulate traffic, and any new tariff would be tested against the principles of Net Neutrality

What are the arguments used by TRAI to justify ban on discriminatory data services?

TRAI has rejected the argument that differential pricing could help increase Internet penetration in India, and eventually encourage users who access a part of the Internet for free to move on to the ‘full Internet’. The regulator said that TSPs can’t be allowed to “define the nature of access” and thus the “users’ internet experience.” It also questioned how users who can’t afford data in the first place will eventually move on to the complete Internet, if “they don’t have the resources to do so.”

TRAI has also raised the issue of a conflict of interest when the service provider is also competing with other content providers. It notes that differential pricing would give these service providers an unfair advantage. What this means is that the big teleco players like Airtel, Vodafone, which have often clubbed free content such as movies or music with their apps like Airtel Wynk or Vodafone Play are also affected.

TRAI’s order essentially quashes the power of TSPs to provide their content for free on their networks.

Has TRAI really come out in support of Net Neutrality and the open internet principle?

By far, this is the strongest endorsement of Net Neutrality that TRAI has given. However, the issue of VoIP apps like WhatsApp or Skype and whether they could come under a licensing regime as telecos have been demanding, remains unresolved.

Technically, India still does not have a law that endorses Net Neutrality as whole. Until the Parliament passes one, the latest order is the closest India has to a pro-Neutrality stand.

TRAI’s order has supported the principle of the open Internet, and says that differential data pricing might “reduce the network effects associated with Internet as the usage of the broad Internet as it exists may go down,” which the regulator believes is not good for society.

The regulator says that just because a TSP is offering data services to the consumers, does not mean that it controls the “Internet infrastructure” in its entirety. This is important since telecos have long argued that while they provide the infrastructure, OTTs and other content providers reap the benefits with their growing user base.

Is the debate on Net Neutrality over?

Although the rules by TRAI are lauded as the strongest rules on Net neutrality in the world, but since there’s no law on the subject, the debate is unlikely to end just yet. As more and more Internet users come online in India, especially via mobile, the fight for their screen space, between telecos, content providers will continue. The lack of a law means that telecos might still go to court against the order.

Net Neutrality Timeline of Events:

April 2015	The issue of Net Neutrality gained popularity in India after Facebook and Airtel planned to launch and push their Free Basic and Airtel zero program respectively in the market. Internet activists opposed these, calling them a blatant violation of Net Neutrality. The issue then rages on for most of 2015.
July 2015	The Department of Telecommunications’ (DoT’s) Net Neutrality report was issued, which said that the core principles of NN had to be “adhered”. It also said that a user’s rights on the Internet need to be protected
February 2016	TRAI issued its ‘Prohibition of Discriminatory Tariffs for Data Services Regulations, 2016’ order which was seen as the first victory for Net Neutrality in India.
January 2017	TRAI had invited public views on the net neutrality issue to finalise a framework. “The purpose of this second stage of consultation is to proceed towards the formulation of final views on policy or regulatory interventions, where required, on the subject of Net Neutrality,”
April 2017	Supreme Court heard plea against the online content violative of Section 22 of PNPCDT Act The apex court made an important observation which is relevant in context of net neutrality as well: "Citizens have the right to access the Internet to gain information, wisdom and knowledge and their right cannot be curtailed unless it encroaches into the boundary of illegality"
November 2017	TRAI had recommended its thoughts on Net Neutrality and upheld the basic principles that ISPs, TSPs (Telecom Service Providers) must treat all data packets the same, and not discriminate on the basis of content. The recommendations followed a consultation process that lasted for over a year.
July 2018	Indian Government approves Net Neutrality Rules  to ensure that all web traffic is treated fairly. Internet service providers will need to agree to the deal when they sign license agreements with the Department of Telecommunications. ISPs that violate the rules could have their licenses canceled.

It must be remembered that no one owns the Internet, so it should be open and accessible to everyone. Service providers have the power of becoming gatekeepers of the Internet but they should not indulge in doing so with this important platform.