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CHAPTER 1
WIRELESS COMMUNICATION
1. INTRODUCTION
Wireless communication is the transfer of information over a distance without the use of
electrical conductors or "wires". The distances involved may be short (a few meters as in
television remote control) or long (thousands or millions of kilometers for radio
communications). Wireless communication is generally considered to be a branch of
telecommunications.
It encompasses various types of fixed, mobile, and portable two-way radios, cellular telephones,
personal digital assistants (PDAs), and wireless networking. Other examples ofwireless
technology include GPS units, garage door openers and or garage doors, wireless computer mice,
keyboards and headsets,satellite television and cordless telephones.
Wireless operations permits services, such as long-range communications, that are impossible or
impractical to implement with the use of wires. The term is commonly used in the
telecommunications industry to refer to telecommunications systems (e.g. radio transmitters and
receivers, remote controls, computer networks, network terminals, etc.) which use some form of
energy (e.g. radio frequency (RF), infrared light, laserlight, visible light, acoustic energy, etc.) to
transfer information without the use of wires. Information is transferred in this manner over both
short and long distances.
In 1895, Guglielmo Marconi opened the way for modern wireless communications by
transmitting the three-dot Morse code for the letter S over a distance of three kilometers using
electromagnetic waves. From this beginning, wireless communications has developed into a key
element of modern society.
From satellite transmission, radio and television broadcasting to the now ubiquitous mobile
telephone, wireless communications has revolutionized the way societies function.
Wireless communications and the economic goods and services that utilise it have some special
characteristics that have motivated specialised studies. First, wireless communications relies on a
scarce resource namely, radio spectrum. Second, use of spectrum for wireless communications
required the development of key complementary technologies; especially those that allowed
higher frequencies to be utilised more efficiently. Finally, because of its special nature, the
efficient use of spectrum required the coordinated development of standards. Those standards in
turn played a critical role in the diffusion of technologies that relied on spectrum use.
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1.1 PRINCIPLES OF WIRELESS COMMUNICATIONS
Wireless communications begin with a message that is converted into an electronic signal by a
device called a transmitter. There are two types of transmitters: analog
and digital. An analog transmitter sends electronic signals as modulated radio waves. The analog
transmitter modulates the radio wave to carry the electronic signal and then sends the modified
radio signal through space. A digital transmitter encodes electronic signals by converting
messages into a binary code, the series of zeros and ones that are the basis of all computer
programming. The encoded electronic signal is then sent as a radio wave. Devices known as
receivers decode or demodulate the radio waves and reproduce the original message over a
speaker.
Wireless communications systems involve either one-way transmissions, in which a person
merely receives notice of a message, or two-way transmissions, such as a telephone conversation
between two people. An example of a device that only receives one-way transmission is a pager,
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which is a high-frequency radio receiver. When a person dials a pager number, the pager
company sends a radio signal to the desired pager.
The encoded signal triggers the pagers circuitry and notifies the customer carrying the pager of
the incoming call with a tone or a vibration, and often the telephone number of the caller.
Advanced pagers can display short messages from the caller, or provide news updates or sports
scores.
Two-way transmissions require both a transmitter and a receiver for sending and receiving
signals. A device that functions as both a transmitter and a receiver is called a transceiver.
Cellular radio telephones and two-way radios use transceivers, so that back-and-forth
communication between two people can be maintained. Early transceivers were very large, but
they have decreased in size due to advances in technology. Fixed-base transceivers, such as those
used at police stations, can fit on a desktop, and hand-held transceivers have shrunk in size as
well. Several current models of handheld transceivers weigh less than 0.2 kg (0.5 lb). Some
pagers also use transceivers to provide limited response options. These brief return-
communication opportunities allow paging users to acknowledge reception of a page and torespond using a limited menu of options.
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1.2 TYPES OF WIRELESS COMMUNICATION
1.2.1
Infrared Wireless Transmission- "Transmission of data signals using infrared-light waves".
These infrared-light waves are at a frequency too low for human eyes to receive and interpret.
Infrared ports can be found in digital cameras, laptops, and printers as well as wireless mice.
Broadcast Radio- a wireless transmission medium that sends data over long distances (regions,
states, countries) at up to 2 megabits per second (AM/FM Radio)
Microwave Radio- Transmission of voice and data through the atmosphere as super high-
frequency radio waves called microwaves. These frequencies are used to transmit messages
between ground-based stations and satellite communications systems.
Communications Satellites- are microwave relay stations in orbit around the earth.
1.2.2
Infrared Wireless Transmission: Wireless infrared communications refers to the use offree-space propagation of light waves in the near infrared band as a transmission mediumfor communication, as shown in Figure1. The communication can be between one portablecommunication device and another or between a portable device and a tethered device,called an access point or base station. Typical portable devices include laptop computers,personal digital assistants, and portable telephones, while the base stations are usuallyconnected to a computer with other networked connections.
Fig 1: A typical wireless infrared communication system
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Wireless infrared communication systems can be characterized by the application for which they
are designed or by the link type, as described below.
Applications
The primary commercial applications are as follows:
Short-term cable-less connectivity for information exchange (business cards, schedules, file
sharing) between two users. The primary example is IrDA systems
wireless local area networks (WLANs) provide network connectivity inside buildings. This can
either be an extension of existing LANs to facilitate mobility, or to establish ad hoc" networks
where there is no LAN. building-to-building connections for high-speed network access or
metropolitan- or campus-area networks. wireless input and control devices, such as wireless
mice, remote controls, wireless game controllers, and remote electronic keys.
Link Type
Another important way to characterize a wireless infrared communication system is by the link
type", which means the typical or required arrangement of receiver and transmitter. Figure 2
depicts the two most common configurations: the point-to-point system and the diffuse system.
The simplest link type is the point-to-point system. There, the transmitter and receiver must be
pointed at each other to establish a link. The line-of-sight(LOS) path from the transmitter to the
receiver must be clear of obstructions, and most of the transmitted light is directed toward thereceiver. Hence, point-to-point systems are also called directed LOS systems. The links can be
temporarily created for a data exchange session between two users, or established more
permanently by aiming a mobile unit at a base station unit in the LAN replacement application.
In diffuse systems, the link is always maintained between any transmitter and any receiver in the
same vicinity by reflecting or bouncing" the transmitted information-bearing light off reflecting
surfaces such as ceilings, walls, and furniture. Here, the transmitter and receiver are non-
directed; the transmitter employs a wide transmit beam and the receiver has a wide field-of-view.
Also, the LOS path is not required. Hence, diffuse systems are also called non-directed non-LOS
systems. These systems are well suited to the wireless LAN application, freeing the user fromknowing and aligning with the locations of the other communicating devices.
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Fig. 2: Common types of infrared communication systems
Wireless infrared communication systems enjoy significant advantages over radio systems in
certain environments. First, there is an abundance of unregulated optical spectrum available. This
advantage is shrinking some what as the spectrum available for licensed and unlicensed radio
systems increases due to modernization of spectrum allocation policies.
Radio systems must make great efforts to overcome or avoid the effects of multipath fading,
typically through the use of diversity. Infrared systems do not suffer from time-varying fades due
to the inherent diversity in the receiver. This simplifies design and increases operational
reliability.
Infrared systems provide a natural resistance to eavesdropping, as the signals are confined withinthe walls of the room. This also reduces the potential for neighboring wireless communication
systems to interfere with each other, which is a significant issue for radio-based communication
systems.
In band interference is a significant problem for both types of systems. A variety of electronic
and electrical equipment radiates in transmission bands of current radio systems; microwave
ovens are a good example. For infrared systems, ambient light, either man-made or natural, is a
dominant source of noise.
The primary limiting factor of infrared systems is their limited range, particularly when no good
optical path can be made available. For example, wireless communication between conventional
rooms with opaque walls and doors cannot be accomplished; one must resort to using either a
radio-based or a wire line network to bypass the obstruction.
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Radio broadcasting is an audio (sound) broadcasting service, broadcast through the air as radio
waves (a form of electromagnetic radiation) from a transmitter to an antenna and a thus to a
receiving device. Stations can be linked in radio networks to broadcast common programming,
either in syndication or simulcast or both. Audio broadcasting also can be done via cable FM,
local wire networks, satellite and the Internet.
Types
Transmission and reception schematic
The best known type of radiostation is the ones that broadcast via radio waves. These include
foremost AM and FM stations. There are several subtypes, namely commercial,public and
nonprofit varieties as well as student-run campus radio stations and hospital radio stations can be
found throughout the developed world.
Although now being eclipsed by internet-distributed radio, there are many stations that broadcaston shortwavebands using AM technology that can be received over thousands of miles(especially at night). For example, the BBC has a full schedule transmitted via shortwave. Thesebroadcasts are very sensitive to atmospheric conditions and solar activity.
Also, many other non-broadcast types of radio stations exist. These includebase stations for
police,fire and ambulance networks, militarybase stations, dispatchbase stations fortaxis,trucks, and couriers,emergency broadcast systems, and amateur radio stations.
Shortwave
Used largely for international broadcasts by organs of state propaganda, religious organizations,militaries and others.
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AM
AM stations were the earliest broadcasting stations to be developed. AM refers to amplitudemodulation, a mode of broadcasting radio waves by varying the amplitude of the carrier signal inresponse to the amplitude of the signal to be transmitted. Many countries outside of the U.S. usea similar frequency band for AM transmissions. Europe also uses the long wave band. In response to the growing popularity of FM radio stereo radio stations in the late 1980s and early1990s, someNorth American stations began broadcasting in AM stereo, though this never gained
popularity, and very few receivers were ever sold.
FM
FM refers to frequency modulation, and occurs on VHF airwaves in the frequency range of 88 to108 MHz everywhere (except Japan and Russia). Japan uses the 76 to 90 MHz band. Russia hastwo bands widely used by the Soviet Union, 65.9 to 74 MHz and 87.5 to 108 MHz worldwidestandard. FM stations are much more popular in economically developed regions, such as Europeand the United States, especially since higher sound fidelity and stereo broadcasting becamecommon in this format.
FM radio was invented by Edwin H. Armstrong in the 1930s for the specific purpose ofovercoming the interference (static) problem of AM radio, to which it is relatively immune. Atthe same time, greater fidelity was made possible by spacing stations further apart. Instead of 10kHz apart, they are 200 kHz apart. This was far in advance of the audio equipment of the 1940s,but wide interchannel spacing was chosen to take advantage of the noise-suppressing feature ofwideband FM.
The AM radio problem of interference at night was addressed in a different way. At the time FMwas set up, the available frequencies were far higher in the spectrum than those used for AMradio - by a factor of approximately 100. Using these frequencies meant that even at far higherpower, the range of as given FM signal was much lower, thus its market was more local than for
AM radio. The reception range at night is the same as at daytime.
The original FM radio service in the U.S. was the Yankee Network, located in New England.Regular FM broadcasting began in 1939, but did not pose a significant threat to the AMbroadcasting industry. It required purchase of a special receiver. The frequencies used, 42 to 50MHz, were not those used today. The change to the current frequencies, 88 to 108 MHz, beganafter the end of World War II, and it was to some extent imposed by AM radio owners so as toattempt to cripple what was by now realized to be a potentially serious threat.
FM radio on the new band had to begin from the ground floor. As a commercial venture itremained a little-used audio enthusiasts' medium until the 1960s. The more prosperous AM
stations, or their owners, acquired FM licenses and often broadcast the same programming on theFM station as on the AM station ("simulating"). The FCC limited this practice in the 1970s. Bythe 1980s, since almost all new radios included both AM and FM tuners, FM became thedominant medium, especially in cities. Because of its greater range, AM remained more commonin rural environments.
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Satellite
Satellite radiobroadcasters are slowly emerging, but the enormous entry costs of space-based
satellite transmitters, and restrictions on available radio spectrum licenses has restricted growth
of this market. In the USA and Canada, just two services, XM Satellite Radio and Sirius Satellite
Radio exist. Both XM and Sirius are owned by Sirius XM Radio, which was formed by the
merger of XM and Sirius on July 29, 2008, whereas in Canada,XM Radio Canada and Sirius
Canada remain separate companies.
Microwave Radio:
Microwave radio relay is a technology for transmitting digital and analog signals, such as long-
distance telephone calls and the relay oftelevision programs to transmitters, between two
locations on a line of sight radio path. In microwave radio relay, radio waves are transmitted
between the two locations with directional antennas, forming a fixed radio connection between
the two points. Long daisy-chained series of such links form transcontinental telephone and/or
television communication systems.
How microwave radio relay links are formed
Relay towers on Frazier Mountain, Southern California
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Because a line of sight radio link is made, the radio frequencies used occupy only a narrow path
between stations (with the exception of a certain radius of each station). Antennas used must
have a high directive effect; these antennas are installed in elevated locations such as large radio
towers in order to be able to transmit across long distances. Typical types of antenna used in
radio relay link installations areparabolic reflectors, shell antennas and horn radiators, which
have a diameter of up to 4 meters. Highly directive antennas permit an economical use of the
available frequency spectrum, despite long transmission distances.
Over-horizon microwave radio relay
In over-horizon, ortropospheric scatter, microwave radio relay, unlike a standard microwave
radio relay link, the sending and receiving antennas do not use a line of sight transmission path.
Instead, the stray signal transmission, known as "tropo - scatter" or simply "scatter," from the
sent signal is picked up by the receiving station. Signal clarity obtained by this method depends
on the weather and other factors, and as a result a high level of technical difficulty is involved inthe creation of a reliable over horizon radio relay link. Over horizon radio relay links are
therefore only used where standard radio relay links are unsuitable (for example, in providing a
microwave linkto an island).
Usage of microwave radio relay systems
During the 1950s the AT&T Communications system of TD radio grew to carry the majority of
US Long Distance telephone traffic, as well as intercontinentaltelevision networksignals.
Similar systems were soon built in many countries, until the 1980s when the technology lost its
share of fixed operation to newer technologies such asfiber-optic cable and optical radio relaylinks, both of which offer larger data capacities at lower cost per bit. Communication satellites,
which are also microwave radio relays, better retained their market share, especially for
television.
At the turn of the century, microwave radio relay systems are being used increasingly in portable
radio applications. The technology is particularly suited to this application because of lower
operating costs, a more efficient infrastructure, and provision of direct hardware access to the
portable radio operator.
Communication Satellite:
A communications satellite (sometimes abbreviated to SATCOM) is an artificial satellitestationed in space for the purpose oftelecommunications. Modern communications satellites usea variety of orbits including geostationary orbits,Molniya orbits, otherelliptical orbits and low(polarand non-polar) Earth orbits.
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For fixed (point-to-point) services, communications satellites provide a microwave radio relaytechnology complementary to that ofsubmarine communication cables. They are also used formobile applications such as communications to ships, vehicles, planes and hand-held terminals,and for TV and radiobroadcasting, for which application of other technologies, such as cable, isimpractical or impossible.
U.S. military MILSTAR communications satellite
Geostationary orbits
A satellite in a geostationary orbit appears to be in a fixed position to an earth-based observer. A
geostationary satellite revolves around the earth at a constant speed once per day over the
equator.
The geostationary orbit is useful for communications applications because ground basedantennas, which must be directed toward the satellite, can operate effectively without the need
for expensive equipment to track the satellites motion. Especially for applications that require a
large number of ground antennas (such as direct TV distribution), the savings in ground
equipment can more than justify the extra cost and onboard complexity of lifting a satellite into
the relatively high geostationary orbit.
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Low-Earth-orbiting satellites
A Low Earth Orbit (LEO) typically is a circular orbit about 400 kilometers above the earths
surface and, correspondingly, a period (time to revolve around the earth) of about 90 minutes.
Because of their low altitude, these satellites are only visible from within a radius of roughly
1000 kilometers from the sub-satellite point. In addition, satellites in low earth orbit change their
position relative to the ground position quickly. So even for local applications, a large number of
satellites are needed if the mission requires uninterrupted connectivity.
Molniya satellites
As mentioned, geostationary satellites are constrained to operate above the equator. As a
consequence, they are not always suitable for providing services at high latitudes: at highlatitudes, a geostationary satellite will appear low on the horizon, affecting connectivity and
causing multipath (interference caused by signals reflecting off the ground and into the ground
antenna).
The first satellite of the Molniya series was launched on April 23,1965and was used for
experimental transmissionof TV signal from a Moscow uplinkstation to downlinkstations
located in Siberia and the Russian Far East, inNorilsk, Khabarovsk, Magadan and Vladivostok.
In November of1967 Soviet engineers created a unique systemof national TV networkof
satellite television, calledOrbita, that was based on Molniya satellites.
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1.3 APPLICATIONS
Broadcasting services: including short wave, AM and FM radio as well as terrestrial
television
Mobile communications of voice and data: including maritime and aeronautical mobile
for communications between ships, airplanes and land; land mobile for communications
between a fixed base station and moving sites such as a taxi fleet and paging services,
and mobile communications either between mobile users and a fixed network or between
mobile users, such as mobile telephone services
Fixed Services: either point to point or point to multipoint services
Satellite: used for broadcasting, telecommunications and internet, particularly over long
distances .Professional LMR (Land Mobile Radio) and SMR (Specialized Mobile Radio)
typically used by business, industrial and Public Safety entities Consumer Two Way
Radio including FRS (Family Radio Service), GMRS (General Mobile Radio Service)
and Citizens band ("CB") radios Consumer and professional Marine VHF radios
Cellular telephones and pagers: provide connectivity for portable and mobile
applications, both personal and business.
Global Positioning System (GPS): allows drivers of cars and trucks, captains of boats
and ships, and pilots of aircraft to ascertain their location anywhere on earth.
Cordless computer peripherals: the cordless mouse is a common example; keyboards
and printers can also be linked to a computer via wireless.
Cordless telephone sets: these are limited-range devices, not to be confused with cell
phones.
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Satellite television: allows viewers in almost any location to select from hundreds of
channels.
Wireless gaming: new gaming consoles allow players to interact and play in the same
game regardless of whether they are playing on different consoles. Players can chat, send
text messages as well as record sound and send it to their friends.
Security systems: Wireless technology may supplement or replace hard wired
implementations in security systems for homes or office buildings.
Television remote control: Modern televisions use wireless (generally infrared) remote
control units. Now radio waves are also used.
Cellular telephony (phones and modems): These instruments use radio waves to enable
the operator to make phone calls from many locations world-wide. They can be used
anywhere that there is a cellular telephone site to house the equipment that is required to
transmit and receive the signal that is used to transfer both voice and data to and from
these instruments.
Wi-Fi: Wi-Fi (for wireless fidelity) is a wireless LAN technology that enables laptop
PCs, PDAs, and other devices to connect easily to the internet. Technically known as
IEEE 802.11 a,b,g,n, Wi-Fi is less expensive and nearing the speeds of standard Ethernet
and other common wire-based LAN technologies
Wireless energy transfer: Wireless energy transfer is a process whereby electrical energy
is transmitted from a power source to an electrical load thatdoes not have a built-in power
source, without the use of interconnecting wires.
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1.4 SERVICES OF WIRELESS COMMUNICATION
Common examples of wireless equipment include:
Telemetry control and traffic control systems Infrared and ultrasonic remote control devices Modulated laser light systems for point to point communications Professional LMR (Land Mobile Radio) and SMR (Specialized Mobile Radio) typically
used by business, industrial and Public Safety entities. ConsumerTwo way radio including FRS Family Radio Service, GMRS (General Mobile
Radio Service) and Citizens band ("CB") radios. The Amateur RadioService (Ham radio). Consumer and professional Marine VHF radios. Airband and radio navigation equipment used by aviators and air traffic control Cellular telephones and pagers: provide connectivity for portable and mobile
applications, both personal and business. Global Positioning System (GPS): allows drivers of cars and trucks, captains of boats and
ships, and pilots of aircraft to ascertain their location anywhere on earth. Cordless computer peripherals: the cordless mouse is a common example; keyboards and
printers can also be linked to a computer via wireless using technology such as WirelessUSB orBluetooth
Cordless telephone sets: these are limited-range devices, not to be confused with cellphones.
Satellite television: Is broadcast from satellites ingeostationary orbit. Typical servicesuse direct broadcast satellite to provide multipletelevisionchannels to viewers.
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1.5 ADVANTAGES
Anywhere, Anytime Work
Through wireless communication, working professionals and mobile workers can work and
access the Internet just about anywhere, anytime without the hassles of wires and network cables.
Enhanced Productivity
Workers, students, professionals and others need not be constrained by wired Internet
connections or dial-up connectivity. Wireless Internet connectivity options ensures that work and
assignments can be completed anywhere and enhance overall productivity of all concerned.
Remote Area Connectivity
Workers, doctors and other professionals working in remote-location hospitals and medical
centers can keep in touch with anyone through wireless communication. Non-profit organization
volunteers working in remote and underserved areas can stay connected to the outside world with
the help of wireless communication.
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On-Demand Entertainment Bonanza
For those unable to keep away from their daily soap operas, reality-programs, online TV shows
and Internet surfing or download activities, wireless communication ensures an entertainment
bonanza on--demand and anytime.
Emergency Alerts
Through wireless communication, many emergency situations and crisis situations can beaddressed quickly. Help and other assistance can reach affected areas quickly through early alerts
and warnings provided with the help of wireless communication.
1.6 DISADVANTAGES
Wireless communications are limited by the range of the transmitter
Cost of wireless communication system and components are high
When transmitting data, users must sometimes send smaller bits of data so the information
moves more quickly. The size of the device that's accessing the information is also still an issue.
Many applications need to be reconfigured if they are going to be used through wireless
connections.
Most client/server applications rely on a persistent connection, which is not the case with
wireless.
Since radio waves travel through the atmosphere they can be disturbed by electrical interferences
(such as lightning) that cause static.
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CONCLUSION
Wireless communication is the transfer of information over a distance without the use of
electrical conductors or "wires". It encompasses various types of fixed, mobile, and portable two-
way radios, cellular telephones, personal digital assistants (PDAs), and wireless networking.
Wireless communications begin with a message that is converted into an electronic signal by a
device called a transmitter. The encoded electronic signal is then sent as a radio wave. Devices
known as receivers decode or demodulate the radio waves and reproduce the original message
over a speaker.
There are 4 types wireless communication; they are Infrared Wireless Transmission, Broadcast
Radio, Microwave Radio, Communications Satellites.
Wireless communication is employed for a wide range of applications such as Broadcasting
services, Mobile communications of voice and data, Fixed Services, Satellite, Cellular
telephones and pagers, Global Positioning System , Cordless computer peripherals, Wireless
gaming, Security systems, Wi-Fi, Wireless energy transfer.
Therefore wireless communication is advantageous over the wired communication as we can
work without the hassles of wires and network cables and enhance overall productivity and also
at a higher speed.
CHAPTER-2
EVOLUTION FROM 1G 2G 3G 4G
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2.1 INTRODUCTION TO 1G
First generation
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Almost all of the systems of this generation were Analog systems where voice was considered to
be the main traffic.
1G wireless networks used analog radio signals. Through 1G, a voice call gets modulated to a
higher frequency of about 150MHz and up as it is transmitted between radio towers. This is done
using a technique called Frequency-Division Multiple Access (FDMA).
These systems could often be listened to by third parties.
Drawbacks of 1G
1G compares unfavorably to its successors. It has low capacity, unreliable handoff, poor voice
links, and no security at all since voice calls were played back in radio towers, making these calls
susceptible to unwanted eavesdropping by third parties.
2.1.1
1G -Standards.
Advanced Mobile Phone System
(AMPS) was a 1G standard used in the United States.
Nordic Mobile Telephone (NMT) was a 1G standard used in Nordic countries (Denmark,
Finland, Iceland, Norway and Sweden), as well as in its neighboring countries Switzerland and
Netherlands, Eastern Europe, and Russia. Italy used a telecommunications system called RTMI
Radio Telefono Mobile Integrato.In the United Kingdom, Total Access Communication System (TACS) was used. France used
Radiocom 2000.
2.2 Second generation:-
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2G refers to second generation wireless telecommunication technology. While its predecessor,
1G, made use of analog radio signals, 2G uses digital radio signals. Based on what type of
multiplexing (the process of combining multiple digital data streams into one signal) is
employed, 2G technologies may be categorized by whether they are based on time division
multiple access (TDMA) or code division multiple access (CDMA). Around 60% of the current
market is dominated by standards. of second Generation.
TDMA-based 2G standards
It includes the following:
Global System for Mobile communications (GSM), used worldwide;
Integrated Digital Enhanced Network (IDEN), developed by Motorola and used in the United
States and Canada;
Interim Standard 136 (IS-136) orDigital Advanced Mobile Phone System (D-AMPS), used
in North and South America; and
Personal Digital Cellular (PDC), used in Japan. IS-95, on the other hand, is CDMA-based. Itwas developed by Qualcomm, and is alternately known as TIA-EIA-95 or cdmaOne.
2G cellphone units were generally smaller than 1G units, since they emitted less radio
power.Another advantage of 2G over 1G is that the battery life of a 2G handset lasts longer,
again due to the lower-powered radio signals. Since it transmitted data through digital signals,
2G also offered additional services such as SMS and e-mail. Its lower power emissions also
made 2G handsets safer for consumers to use.
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2.3
2.5 Generation
2.5G, which stands for "second and a half generation," is a cellular wireless techno logy
developed in between its predecessor, 2G, and its successor, 3G. "2.5G" is an informal term,
invented solely for marketing purposes, unlike "2G" or "3G" which are officially defined
standards based on those defined by the Intern ational Teleco mmunication (ITU). The term
"2.5G" usually describes a 2G cellular system comb ined with General Packet Radio Services
(GPRS), or other services not generally fou nd in 2G or 1G networks.GPRS is a service
commonly associated with 2.5G technology. It has data transmission rates of 28 kbps or higher.
GPRS came after the development of the Global System for Mobile (GSM) service, which is
classified as 2G technology, and it was succeeded by the development of the Universal Mobile
Telecommunication Service (UMTS), which is classified as 3G technology.
Improved 2G networks (GPRS) manages to support few of applications like web browsing,
emailing, video streaming, Multimedia messaging service etc. therefore GPRS can also be said
that it is 2.5 generation technology.
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2.4
Third generations:-
3G is the third generation of mobile phone standards and technology, superseding2G, and
preceding 4G.To meet the growing demands in network capacity, rates required for high speed
data transfer and multimedia applications, 3G standards started evolving. It is based on the
International Telecommunication Union(ITU) family of standards under the International
Mobile Telecommunications programmer,IMT-2000.
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2.4.1 TECHNIQUES USED IN 3G
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GSM
Mobile
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Mobile Station (MS)
Mobile Equipment
Fixed
Portable
International Mobile Equipment Identity (IMEI) number
Subscriber Identity Module (SIM)
Personal Identification Number (PIN)
International Mobile Subscriber Identity (IMSI) number
Enables access to subscribed services
Smart card
Base Transceiver Station - BTS
Usually referred to as the Base Station
Provides the interface to the network for the MS
Handles all communications with the MS
intelligence now deployed on MS
for example, when to perform a handover
Transmitting power determines cell size
Base Station Controller - BSC
Controls Base Stations
up to several hundred depending on manufacturer
Manages radio channels
allocation and release
Coordinates Handover
Physical location may vary
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Abis interface
between BSC and BTS
Mobile Switching Centre (MSC)
Performs all switching/exchange functions
Handles registration authentication location updating
A GSM network must have at least one MSC
May connect to other networks
Gateway MSC (GMSC)
Administrative information for all subscribers
Home Location Register (HLR)
IMSI number actual phone number permitted supplementary services current location i.e. whichVLR subscriber is currently registered with One HLR per GSM PL GPRS
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Mobile
GPRS NSS
Two new nodes introduced for packet data
Serving GPRS Support Node (SGSN)
handles all packet data for the appropriate geographic area
monitors GPRS users
handles security and access control
may be regarded as the packet switched equivalent of the circuit-switched MSC
Gateway GPRS Support Node (GGSN)
internetworking functionality
routes incoming data to correct SGSN
translates between different protocols and formats
Details of data services added to HLR
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EDGE
EDGE, or the Enhanced Data Rate for Global Evolution, is the new mantra in the GlobalInternet Connectivity scene. EDGE is the new name for GSM 384. The technology was namedGSM 384 because of the fact that it provided Data Transmission at a rate of 384 Kbps. It consistsof the 8 pattern time slot, and the speed could be achieved when all the 8 time slots were used.The idea behind EDGE is to obtain even higher data rates on the current 200 KHz GSM carrier,by changing the type of the modulation used.Now, this is the most striking feature. EDGE, asbeing once a GSM technology, works on the existing GSM or the TDMA carriers, and enablesthem to many of the 3G services.
Although EDGE will have a little technical impact, since its fully based on GSM or the TDMAcarriers, but it might just get an EDGE over the upcomming technologies, and ofcourse, theGPRS. With EDGE, the operators and service providers can offer more wireless data application,including wireless multimedia,e-mail (Web Based), Web Infotainment, and above all, thetechnology of Video Conferencing.Now all these technologies that were named earlier, were the clauses of the IMT-UMTS 3GPackage. But, with EDGE, we can get all these 3G services on our existing GSM phones, whichmight just prove to be a boon to the user.
2.4.2
STANDARDS USED IN THE 3G MOBILES ARE FOLLOWING
W-CDMA also known as UMTS
CDMA2000
TD-CDMA / TD-SCDMA
UWC (often implemented with EDGE)
DECT
WIMAX
IMT-2000
It is the term used by the International Telecommunications Union (ITU) for a set of globally
harmonized standards for third generation (3G) mobile telecoms services and equipment. 3G
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services are designed to offer broadband cellular access at speeds of 2Mbps, which will allow
mobile multimedia services to become possible.
WIDEBAND CODE DIVISION MULTIPLE ACCESS
(Universal Mobile Telecommunications System)
WCDMA is a wideband spread-spectrum 3G mobile telecommunication air interface that
utilizes code division multiple access .It provides simultaneous support for a wide range of
services with different characteristics on a common 5MHz carrier.
The term WCDMA also refers to one of the International Telecommunications Union's IMT-
2000 standards, a type of 3G cellular network. WCDMA is the technology behind the 3G UMTS
standard and is closely allied with the 2G GSM standard. It provides new service capabilities,
increased network capacity and reduced cost for voice and data services.
The term 'WCDMA Evolved' describes the evolution of WCDMA, addressing both operators'
needs for efficiency and users' demands for enhanced experience and convenience. The first
steps of this evolution are HSDPA and Enhanced Uplink.
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Code division multiple access (CDMA) is a channel access method utilized by various radiocommunication technologies. It should not be confused with the mobile phone standards called
cdmaOne and CDMA2000 (which are often referred to as simply "CDMA"), which use CDMAas an underlying channel access method.
One of the basic concepts in data communication is the idea of allowing several transmitters tosend information simultaneously over a single communication channel. This allows several usersto share a bandwidth of different frequencies. This concept is called multiplexing. CDMAemploys spread-spectrum technology and a special coding scheme (where each transmitter isassigned a code) to allow multiple users to be multiplexed over the same physical channel. Bycontrast, time division multiple access (TDMA) divides access by time, while frequency-division multiple access (FDMA) divides it by frequency. CDMA is a form of "spread-spectrum" signaling, since the modulated coded signal has a much higher data bandwidth thanthe data being communicated.
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CDMA2000 Technologies
CDMA2000 represents a family of standards and includes:
CDMA2000 1X
CDMA2000 1xEV-DO Technologies
CDMA2000 1xEV-DO Rel 0
CDMA2000 1xEV-DO Rev A
CDMA2000 1xEV-DO Rev B
CDMA2000
It is a hybrid 2.5G / 3G technology of mobile telecommunications standards that use CDMA, a
multiple access scheme for digital radio, to send voice, data, and signalling data (such as a dialed
telephone number) between mobile phones and cell sites. CDMA2000 is considered a 2.5G
technology in 1xRTT and a 3G technology in EVDO. CDMA2000 is also known as IS-2000.
Even though "W-CDMA" and "CDMA2000" both have "CDMA" in their names, they are
completely different systems using different technologies. However, it is hoped that mobile
devices using the two systems will be able to talk to each other.
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CDMA2000-1xEVDO System Architecture (Basic)
BTS: Base Station, which creates a single cell
BSC: Base Station Controller, which controls roaming and channel allocations amongst
various BSTs and is also referred to as a Radio Network Controller (RNC).
MSC: Mobile Switching Center, which performs the telephony switching functions and is
usually connected to an SS7 network.
PDSN: Packet Data Serving Node, maintains IP communications between all MNs and the
Packet Data Network (PDN), which in this diagram is the Internet.
Broadband data: Provides a peak data rate of 2.4 Mbps in the forward link and 153 kbps in the
reverse link in a single 1.25 MHz FDD carrier
Offers an "always on" user experience
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Applications: Supports broadband data applications, such as broadband Internet or VPN access,
MP3 music downloads, 3D gaming, TV broadcasts, video and audio downloads.
Evolution-Data Optimized orEvolution-Data only, abbreviated as EV-DO orEVDO and
often EV, is a telecommunications standard for the wireless transmission of data through radio
signals, typically for broadband Internet access. It uses multiplexing techniques including code
division multiple access (CDMA) as well as time division multiple access (TDMA) to maximize
both individual user's throughput and the overall system throughput. It is standardized by 3rd
Generation Partnership Project 2 (3GPP2) as part of the CDMA2000 family of standards and has
been adopted by many mobile phone service providers around the world particularly those
previously employing CDMA networks.
A Packet Data Serving Node (PDSN) provides access to the Internet, intranets and applications
servers for mobile stations utilizing a cdma2000 Radio Access
The public switched telephone network (PSTN) is the network of the world's public circuit-
switched telephone networks
Voice over Internet Protocol (VoIP) is a general term for a family of transmission technologies
for delivery of voice communications over IP networks such as the Internet or other packet-
switched networks. Other terms frequently encountered and synonymous with VoIP are IP
telephony, Internet telephony, voice over broadband (VoBB), broadband telephony, and
broadband phone.
Key features of CDMA2000 are:
Leading erformance.
Efficient use of spectrum.
Support for advanced mobile services.
Devices selection.
Seamless evolution path .
Flexibility .
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CDMA2000 Advantages
Superior Voice Clarity
High-Speed Broadband Data Connectivity
Low End-to-End Latency
Increased Voice and Data Throughput Capacity
Improved Security and Privacy
Lower Total Cost of Ownership (TCO)
Time Division Code Division Multiple Access
Or
Time Division Synchronous Code
Divi\sion Multiple Access
TD-CDMA, an acronym forTime-division - CDMA, is a channel access method based on using
spread spectrum across multiple time slots.[1] It is shown that a mixture of TDMA and CDMA
provides better quality of service for multimedia communications in terms of data throughput
and voice/video quality.
TD-SCDMA is being pursued in the People's Republic of China by the Chinese Academy of
Telecommunications Technology (CATT), Datang and Siemens AG, in an attempt not to be
dependent on Western technology. This is likely primarily for practical reasons, other 3G
formats require the payment of patent fees to a large number of Western patent holders [4].
TD-SCDMA uses the Time Division Duplex (TDD) mode,
Time-division duplexing (TDD) is the application of time-division multiplexing to separate
outward and return signals. It emulates full-duplex communication over a half-duplex
communication link. Time-division duplex has a strong advantage in the case where there is
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asymmetry of the uplink and downlink data rates. As the amount of uplink data increases, more
communication capacity can be dynamically allocated, and as the traffic load becomes lighter,
capacity can be taken away. The same applies in the downlink direction.
In January 2009 the Ministry of Industry and Information Technology (MIIT) in China took the
unusual step of assigning licences for 3 different third-generation mobile phone standards to
three carriers in a long-awaited step that is expected to prompt $41 billion in spending on newequipment. The Chinese-developed standard, TD-SCDMA, was assigned to China Mobile, the
world's biggest phone carrier by subscribers. That appeared to be an effort to make sure the new
system has the financial and technical backing to succeed. Licences for two existing 3G
standards, WCDMA and CDMA-2000, were assigned to China Unicom and China Telecom,
respectively. Third-generation, or 3G, technology supports Web surfing, wireless video and other
services and the start of service is expected to spur new revenue growth.
DECT
Digital Enhanced Cordless Telecommunications (DECT), known as Digital EuropeanCordless TelephonE until 1995, is an ETSI standard for digital portable phones (cordless hometelephones), commonly used for domestic or corporate purposes. It is recognised by the ITU asfulfilling the IMT-2000 requirements and thus qualifies as a 3G system. Within the IMT-2000group of technologies, DECT is referred to as IMT-2000 Frequency Time (IMT-FT)
DECT was developed by ETSI but has since been adopted by many countries all over the world.The original DECT frequency band (1880MHz1900 MHz) is used in all countries inEurope.Outside Europe, it is used in most of Asia, Australia and South America. In the United States, theFederal Communications Commission in 2005 changed channelization and licensing costs in a
nearby band (1920 MHz1930 MHz, or 1.9 GHz), known as Unlicensed PersonalCommunications Services (UPCS), allowing DECT devices to be sold in the U.S. with onlyminimal changes. These channels are reserved exclusively for voice communication applicationsand therefore are less likely to experience interference from other wireless devices such as babymonitors and wireless networks.
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2.4.3
THE GROWTH OF 3G IN INDIA
India is seeing an unprecedented increase in the mobile users. According of one of the latest
TRAI reports released in November 2008, the total number of mobile users in India has reached
325 million. In October 2008 alone, 10.42 million new subscribers added. These figures are
bound to shoot up with the launch of 3G network.Some of the major mobile players in India are
BSNL mobile, Airtel mobile, Reliance mobile and Tata mobile. At one time Aircel mobile wasleading the market; however, it has now lost the market share to BSNL mobile, Airtel mobile and
other leading mobile players.
With 3G network, mobile internet will have its internet capabilities enhanced and we will be able
to have mobile broadband. BSNL mobile is planning to launch 3G network in January 2009.
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Airtel is expected to follow suit with 3G network. Airtel has already launched the Apple 3G
iPhone in India in August 2008.
With so much of competition in the mobile telecom industry, we can expect the tariffs for mobile
broadband network from BSNL broadband, Airtel broadband and other leading players to behighly competitive. We can expect a great reception from the Indian mobile consumers. Mobile
broadband is bound to change the entire internet experience. People who are currently using
GPRS connection to surf the internet while they are on the move using their mobile phones,
PDAs and Laptops know how convenient it is to have internet on the move. You can accom
plish a lot of work even as you move from one place to the other and your business will not
suffer because you are travelling. However, one of the pains of using GPRS connection is their
painfully slow connections. We can over come these internet speed issues with 3G mobile
network. We can enjoy internet at the speed of broadband not only at our homes and offices we
can enjoy high-speed internet connections even while travelling.
Most of us are closely following the announcements from all leading mobile players in India on
their efforts to bringing 3G network to the Indian mobile community. It is rather surprising to
note why Airtel who brought a revolution in the mobile industry, competitive rates and excellent
services have not managed to launch 3G service yet.
All those who have been waiting for the 3G network in India has reached the state of frustration
as there is no word from the telecom department regarding when exactly we will be able to enjoy
mobile broadband in India except for the occasional remarks from the leading mobile players in
India such as BSNL mobile. Though BSNL mobile has plans to launch 3G network in January2009, we can never be sure when exactly this will be realized. Interestingly, not many
international players are interested in bidding in the 3G network auctions. However, if
international players come in there will be an increased competition in the industry that will
work for the advantage of the end users in terms of better-priced 3G solutions.
3G ENABLED HANDSETS IN INDIA
Here are the top ten 3G phones of 2009 and their price in Indian Rupees
1. Nokia E 71 Rs. 19,700
2. Apple iphone 3G Rs. 29800
3. Samsung Pixon Rs.30999
4. Nokia N85 Rs.22,000
5. Blackberry Bold Rs 34990
6. Blackberry Storm Rs 27990 (Only available bundled with Vodafone connection)
7. LG Secret Rs. 22000
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8. INQ 1 (Price not available)
9. Sony Ericsson C905 Rs.31,000
10. Samsung Omnia Rs.31,200
3G in India by mid 2009 but with spectrum curbs
With the Government issuing guidelines for 3G, high speed mobile downloads and live
television on mobile will finally become a reality by middle of 2009. But customers in Delhi or
Mumbai may not have much to look forward to.
Due to spectrum constraints, there are merely three Global System for Mobile (GSM) operators
that can offer 3G services. With one slot already reserved for MTNL and the other two open for
global bids, customers in Delhi and Mumbai may end up missing the 3G bus if they dont switch
operators.But customers in Tamil Nadu, Karnataka and Kerala could have as many as 10
operators to choose from.
"Subject to the availability of 3G spectrum, we will have five operators to start with and
gradually we may go up to having ten operators. In Mumbai and Delhi, however, we can only
have 2-3 operators, Communications and IT Minister D Raja said.Even private GSM operators
admit that limited spectrum will lead to overbidding and could render 3G services unaffordable.
"If there is a supply constraint and demand excess, obviously there will be overbidding, which
could make 3G very expensive in Delhi and Mumbai," Director General, Cellular Operators
Association of India (COAI), T V Ramachandran cautions.But analysts say it is unlikely that the
big GSM players like Airtel and Vodafone will not bid aggressively to ensure they get 3G
spectrums, primarily because most customers with an appetite for 3G are locked in the two
networks.
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2.4.4
ADVANTAGES OF 3G TECHNOLOGY
3G has supplied a fresh way of living amongst cellular phone and handset users with consumersrapidly getting on the bandwagon and putting money into 3G-powered devices and tools. 3G canalter the way in which you look at network, with the various features as well as effects. Youcould move forward and take advantage of the highest details as well as tools by understandingthe operations and applications of the system, as well as the current networks.
The Operations
Individuals can perform many operations such as sending information and data and getting thesevia wireless access. You can obtain information no matter the time and location. 3G is thecurrent mobile technology and is currently the most rapidly growing host among mobilehandsets, giving you the greater speeds, in comparison to other technologies that preceded it.
You are able to have faster connection, audio entertainment with greater quality and fasterInternet access. You also receive the advantages of video calling because of the greater speed,
enjoying phone calls to family as well as friends all over the world with the video calling feature.The caliber and clarity are enhanced, with the ability usable provided the two parties areemploying the 3G innovations.
Utilizing the Technology
People may utilize their phones and allow them to work as a modem for their computer to mailand send necessary documents. Downloading audio tracks as well as games would be a lot
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quicker compared to older technologies. The tech additionally allows extremely quickdownloads, so you need only a couple minutes to download albums and movie clips.
Getting Info
Obtaining info is among of the best features of 3G technology which means you can also watchthe latest news and newspaper headlines, receiving information such as weather reports, sportsnews and even economy related information. You have the ability to acquire the latest scores in
an ongoing baseball match and other favorite sports or shows. The improved caliber of facilitiesas well as speed of 3G devices may permit you to see music clips as well as film clips with veryclear photographs, when held in comparison to 2.5G technology devices.
Faster Speed
Using 3G technology, you get to enjoy data transmission speed leading up to 2Mbps, providingyou have a phone stationary. It additionally provides you heightened level of connectivity as wellas greater networking, in addition to noise resistance. The tech has raised the bit rate, allowingservice providers to give high speed Internet capabilities, greater call numbers and lot of themultimedia apps that can be given to the consumers. All of the facilities can be given to the
customers based on the data quantity sent and not upon the time used for the service, so theservices given to customers are more inexpensive.
On Price
In spite of the new speeds and capabilities of 3G tech, the costs of handsets are relatively thesame, with the most recent types, though, being priced higher to those featuring 2.5G, althoughInternet bargains are around.
Disadvantages of 3G technology
Expensive input fees for the 3G service licenses
Numerous differences in the licensing terms
Large amount of debt currently sustained by many
telecommunication companies, which makes it a challenge to build the necessary infrastructure
for 3G
Lack of member state support for financially troubled operators
Expense of 3G phones
Lack of buy-in by 2G mobile users for the new 3G wireless services GE
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2.5 Fourth Generation:-
The 4G working group has defined the following as objectives of the 4G wirelesscommunication standard:
A spectrally efficientsystem (in bits/s/Hz and bits/s/Hz/site),
High network capacity: more simultaneous users per cell,
A nominal data rate of 100 Mbit/s while the client physically moves at high speeds relative to the
station, and 1 Gbit/s while client and station are in relatively fixed positions as defined by the
ITU-R,
A data rate of at least 100 Mbit/s between any two points in the world,
Smooth handoff across heterogeneous networks
Seamless connectivity and global roaming across multiple networks,
High quality of service for next generation multimedia support (real time audio, high speed data,
HDTV video content, mobile TV, etc
Interoperability with existing wireless standards, and
An all IP, packet switched network
In summary, the 4G system should dynamically share and utilize network resources to meet the
minimal requirements of all the 4G enabled users
2.5.1
SWOT ANALYSIS OF 4G
Strengths in 4G:
4G visions take into account installed base and past investments
Strong position of telecommunications vendors expected in the marketplace
- Faster data transmission and higher bit rate and bandwidth, allow more
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business applications and commercialization
- Has advantage for personalized multimedia communication tools
Weakness in 4G:
No large user community for advanced mobile data applications yet
- Growing divergence between telecommunications vendors and operators
- Not possible to offer full internet experience due to limited speed and
Bandwidth
- Comparatively higher cost to use and deploy infrastructure compared fast
mobile generation
Opportunities in 4G:
Evolutionary approach may yield opportunities for the 4G.
- Sophisticated and mature commercialization of 4G technology would
encourage more applications of e-commerce and m-commerce
- Worldwide economy recover stimulates consumption and consumer
confidence, therefore bring in opportunities for telecommunication sections
- It is expected and predicted that consumers will continue to replace handsets
with newer technology at a fast rate.
- Desirable higher data capacity rates, the growth opportunity for 4G is very
bright and hopeful
Threats in 4G:
Faster rate of growth and developments in other region
- Since 3G mobile is still in the market, it squeezes the market competition in
the mobile industry
Conclusion
As we come up with the SWOT analysis out of this 4G technology, it is inevitable that 4G
would completely replace 3G in a long run. Nevertheless, 4G and 3Gtend to keep a co-
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competitive relationship in a short run. In order for 4G to grow in the future market, it is
unavoidable to compete with 3G and acquire 3Gs customers.
2.5.2
Future of 3G and 4G networks
Like any new technological development, 4G is a lot closer than you think. Tests are alreadyunderway and some battle lines are being drawn with regards to how the market for theseservices will emerge. This development is on track to coincide with the equally rapiddevelopment of real time systems like Twitter and Google Wave. What is likely to emerge areservices that create instantaneous streams to deliver and share not just text and hyperlinks, butvideo, audio, whiteboarding and files. This will be:a) Fasterb) From a static or mobile device
c) With more reliable synchronization via the cloudd) Easily archivable and searchable
Even more exciting is the continued evolution in hardware and always on devices. Taking theiPhone as an example, its gyroscope has redefined gaming and sent the experience into a muchmore physical dimension. The Wii is another case, even being used as part of physical therapyregimens.
The near future will bring devices that rapidly stream real time data that can be manipulatedphysically via mobile devices around the world. This data will be searchable and archivable viathe cloud. Data will also be semantically organized and re-configurable into other views that
reveal insights for business owners and managers.
With all of the possibilities that this brings, planning for the roll out of these technologiesrequires a broad knowledge of what will become available, but it also requires significant focusbecause, taking Twitter as an example, the most compelling applications often use a subset ofwhat is available. Technologically, Twitter is not particularly complex, but it has met a humanneed.
4G will provide the playing field for the next Twitter or Facebook, provided that a developersand entrepeneurs are able to ask the right questions and stay focused on meeting human needs,rather than geeking out.
More importantly, is poses the questions that need to be asked by anyone who will be taking partin that space. It is important to remember that 4G, beyond being a mobile technology, will be aconvergence of technologies. Desktop, remote, mobile, and new interfaces will continue to makeit impossible to focus on one single type of device for anyone hoping to compete in the nextseveral years.
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2.5.3
DIFFERENCES BETWEEN 3G AND 4G TECHNOLOGIES
There has been more talk about 4G (fourth generation) mobile broadband recently and Nokia
Siemens Networks (NSN's) has announced that the first 4G field trials have been completed in
Berlin.
As 4G seems to have taken a step closer to reality, I decided to do some research and find out
what advantages 4G may offer over 3G. The specifications for 4G are not standardized yet but
the following 3G vs 4G table gives an idea of what 4G is likely to provide.
Technology3G 4G
Frequency band1.8 - 2.5GHz 2 - 8GHz
Bandwidth5-20MHz 5-20MHz
Data rateUp to 2Mbps 100Mbps moving - 1Gbps stationary
AccessW-CDMA VSF-OFCDM and VSF-CDMA
Switching Circuit/Packet Packet
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The existing 3G W-CDMA standard will be replaced in 4G by VSF-OFCDM and VSF-CDMA.
VSF-OFCDM allows extremely high downlink connections, both indoors and outdoors. VSF-
CDMA provides high-efficiency, high-speed packet transmissions for the uplink.
The 4G adoption of concatenated FEC (Forward Error Correction) will allow much larger data
packets to be transmitted and at the same time reduce the bit error rate. This will increase the
overall data through-put.
One of the main advantages that 4G technology will have over 3G is higher data rates. This will
benefit the end user by allowing faster access to multimedia and video while on the move.
We may still have to wait a while for 4G though, as it looks like 4G networks won't be launched
until 2008 and won't become widely available until 2010.
Conclusion:
Availability could be years off
4Gs predecessor, 3G wireless, is still taking off. The fourth-largest wireless-service provider, T-
Mobile. So if 3G is just getting going, what does that mean for 4G?
Opinions on when 4G services might be available differ.
But if standards dont come before 2015, as Gartners Redman predicts, true 4G services could
come only after 2015.
4G will open the door to a variety of mobile apps
Some analysts agree there is no killer app for 4G today. But with the mobile speeds being
proposed with 4G, customers could participate in live video conferences while on the go or
access bandwidth-intensive applications.
Abstract:
Wikipedia,
http://en.wikipedia.org/wiki/3G
http://searchmobilecomputing.techtarget.com/sDefinition/0,,sid40_gci505555,00.html
http://en.wikipedia.org/wiki/Wikipediahttp://en.wikipedia.org/wiki/3Ghttp://searchmobilecomputing.techtarget.com/sDefinition/0,,sid40_gci505555,00.htmlhttp://en.wikipedia.org/wiki/Wikipediahttp://en.wikipedia.org/wiki/3Ghttp://searchmobilecomputing.techtarget.com/sDefinition/0,,sid40_gci505555,00.html8/3/2019 Evolution 1G to 4G
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http://acronyms.thefreedictionary.com/TCDMA
http://www.dectweb.com/default.html
http://acronyms.thefreedictionary.com/TCDMAhttp://acronyms.thefreedictionary.com/TCDMATop Related