4G Wireless Systems

Yuben Joseph

School Of Management Studies

CUSAT, Kochi-22
E-mail: yubenjoseph@gmail.com

Abstract: Fourth generation wireless system is a packet switched wireless system

with wide area coverage and high throughput. It is designed to be cost effective
and to provide high spectral efficiency. The 4g wireless uses Orthogonal Frequency
Division Multiplexing (OFDM), Ultra Wide Radio Band (UWB),and Millimeter
wireless. Data rate of 20mbps is employed. Mobile speed will be up to 200km/hr.
The high performance is achieved by the use of long term channel prediction, in
both time and frequency, scheduling among users and smart antennas combined
with adaptive modulation and power control. Frequency band is 2-8 GHz. it gives
the ability for worldwide roaming to access cell anywhere.

Keywords: Mobile, internet, 4G, GPRS, EDGE

1.0 INTRODUCTION

W Wireless mobile-communications systems are uniquely identified by "generation"

designations. Introduced in the early 1980s, first-generation (1G) systems were marked
by analog-frequency modulation and used primarily for voice communications.
Second - generation (2G) wireless-communications systems, which made their
appearance in the late 1980s, were also used mainly for voice transmission and
reception The wireless system in widespread use today goes by the name of 2.5G—an
"in-between" service that serves as a stepping stone to 3G. Whereby 2G
communications is generally associated with Global System for Mobile (GSM) service,
2.5G is usually identified as being "fuelled" by General Packet Radio Services (GPRS)
along with GSM. In 3G systems, making their appearance in late 2002 and in 2003, are
designed for voice and paging services, as well as interactive-media use such as
teleconferencing, Internet access, and other services. The problem with 3G wireless
systems is bandwidth—these systems provide only WAN coverage ranging from 144
kbps (for vehicle mobility applications) to 2 Mbps (for indoor static applications). Segue
to 4G, the "next dimension" of wireless communication. The 4g wireless uses Orthogonal
Frequency Division Multiplexing (OFDM), Ultra Wide Radio Band (UWB), and Millimetre
wireless and smart antenna. Data rate of 20mbps is employed. Mobile speed will be up

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to 200km/hr. Frequency band is 2-8 GHz. it gives the ability for worldwide roaming to
access cell anywhere.

2.0 FEATURES

• Support for interactive multimedia, voice, streaming video, Internet, and other
broadband services

• IP based mobile system

• High speed, high capacity, and low cost-per-bit

• Global access, service portability, and scalable mobile services

• Seamless switching and a variety of Quality of Service-driven services

• Better scheduling and call-admission-control techniques

• Ad-hoc and multi-hop networks (the strict delay requirements of voice make multi-
hop network service a difficult problem)

• Better spectral efficiency

• Seamless network of multiple protocols and air interfaces (since 4G will be all-IP,
look for 4G systems to be compatible with all common network technologies,
including 802.11, WCDMA, Bluetooth, and Hyper LAN).

• An infrastructure to handle pre-existing 3G systems along with other wireless

technologies, some of which are currently under development.

3.0 HISTORY

The history and evolution of mobile service from the 1G (first generation) to fourth
generation are as follows. The process began with the designs in the 1970s that have
become known as 1G. The earliest systems were implemented based on analog
technology and the basic cellular structure of mobile communication. Many
fundamental problems were solved by these early systems. Numerous incompatible
analog systems were placed in service around the world during the 1980s.The 2G
(second generation) systems designed in the 1980s were still used mainly for voice
applications but were based on digital technology, including digital signal processing
techniques. These 2G systems provided circuit-switched data communication services
at a low speed. The competitive rush to design and implement digital systems led
again to a variety of different and incompatible standards such as GSM (global system
mobile), TDMA (time division multiple access); PDC (personal digital cellular) and
CDMA (code division multiple access).These systems operate nationwide or
internationally and are today's mainstream systems, although the data rate for users in
these system is very limited. During the 1990’s the next, or 3G, mobile system, this

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would eliminate previous incompatibilities and become a truly global system. The 3G
system would have higher quality voice channels, as well as broadband data
capabilities, up to 2 Mbps. An interim step is being taken between 2G and 3G, the
2.5G. It is basically an enhancement of the two major 2G technologies to provide
increased capacity on the 2G RF (radio frequency) channels and to introduce higher
throughput for data service, up to 384 kbps. A very important aspect of 2.5G is that the
data channels are optimized for packet data, which introduces access to the Internet
from mobile devices, whether telephone, PDA (personal digital assistant), or laptop.
However, the demand for higher access speed multimedia communication in today's
society, which greatly depends on computer communication in digital format, seems
unlimited. According to the historical indication of a generation revolution occurring
once a decade, the present appears to be the right time to begin the research on a 4G
mobile communication system.

4.0 ABOUT 4G

This new generation of wireless is intended to complement and replace the 3G

systems, perhaps in 5 to 10 years. Accessing information anywhere, anytime, with a
seamless connection to a wide range of information and services, and receiving a large
volume of information, data, pictures, video, and so on, are the keys of the 4G
infrastructures. The future 4G infrastructures will consist of a set of various networks
using IP (Internet protocol) as a common protocol so that users are in control because
they will be able to choose every application and environment. Based on the
developing trends of mobile communication, 4G will have broader bandwidth, higher
data rate, and smoother and quicker handoff and will focus on ensuring seamless
service across a multitude of wireless systems and networks. The key concept is
integrating the 4G capabilities with all of the existing mobile technologies through
advanced technologies. Application adaptability and being highly dynamic are the main
features of 4G services of interest to users. These features mean services can be
delivered and be available to the personal preference of different users and support the
users' traffic, air interfaces, radio environment, and quality of service. Connection with
the network applications can be transferred into various forms and levels correctly and
efficiently. The dominant methods of access to this pool of information will be the
mobile telephone, PDA, and laptop to seamlessly access the voice communication,
high-speed information services, and entertainment broadcast services. The fourth
generation will encompass all systems from various networks, public to private;
operator-driven broadband networks to personal areas; and ad hoc networks. The 4G
systems will interoperate with 2G and 3G systems, as well as with digital (broadband)
broadcasting systems. In addition, 4G systems will be fully IP-based wireless Internet.
This all-encompassing integrated perspective shows the broad range of systems that
the fourth generation intends to integrate, from satellite broadband to high altitude
platform to cellular 3G and 3G systems to WLL (wireless local loop) and FWA (fixed
wireless access) to WLAN (wireless local area network) and PAN (personal area
network),all with IP as the integrating mechanism. With 4G, a range of new services
and models will be available. These services and models need to be further examined
for their interface with the design of 4G systems.

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5.0 APPLICATION

4G technology is significant because users joining the network add mobile routers to
the network infrastructure. Because users carry much of the network with them,
network capacity and coverage is dynamically shifted to accommodate changing user
patterns. As people congregate and create pockets of high demand, they also create
additional routes for each other, thus enabling additional access to network capacity.
Users will automatically hop away from congested routes to less congested routes.
This permits the network to dynamically and automatically self-balance capacity, and
increase network utilization. What may not be obvious is that when user devices act as
routers, these devices are actually part of the network infrastructure. So instead of
carriers subsidizing the cost of user devices (e.g., handsets, PDAs, of laptop
computers), consumers actually subsidize and help deploy the network for the carrier.
With a cellular infrastructure, users contribute nothing to the network. They are just
consumers competing for resources. But in wireless ad hoc peer-to-peer networks,
users cooperate – rather than compete – for network resources. Thus, as the service
gains popularity and the number of users increases, service likewise improves for all
users. And there is also the 80/20 rule. With traditional wireless networks, about 80%
of the cost is for site acquisition and installation, and just 20% is for the technology.
Rising land and labor costs means installation costs tend to rise over time, subjecting
the service providers’ business models to some challenging issues in the out years.
With wireless peer-to-peer networking, however, about 80% of the cost is the
technology and only 20% is the installation. Because technology costs tend to decline
over time, a current viable business model should only become more profitable over
time. The devices will get cheaper, and service providers will reach economies of scale
sooner because they will be able to pass on the infrastructure savings to consumers,
which will further increase the rate of penetration.

5.1 4G Car

With the hype of 3G wireless in the rear view mirror, but the reality of truly mobile
broadband data seemingly too far in the future to be visible yet on the information
super highway, it may seem premature to offer a test drive 4G. But the good news is,
4G is finally coming to a showroom near you.

5.2 4G and public safety

There are sweeping changes taking place in transportation and intelligent highways,
generally referred to as “Intelligent Transportation Systems” (ITS). ITS is comprised of
a number of technologies, including information processing, communications, control,
and electronics. Using these technologies with our transportation systems, and
allowing first responders access to them, will help prevent - or certainly mitigate - future
disasters. Communications, and the cooperation and collaboration it affords, is a key
element of any effective disaster response. Historically, this has been done with bulky
handheld radios that provide only voice to a team in a common sector. And this
architecture is still cellular, with a singular point of failure, because all transmissions to
a given cell must pass through that one cell. If the cell tower is destroyed in the
disaster, traditional wireless service is eliminated.4G wireless eliminates this spoke-
and-hub weakness of cellular architectures because the destruction of a single node

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does not disable the network. Instead of a user being dependent on a cell tower, that
user can hop through other users in dynamic, self roaming, self-healing rings. This is
reason enough to make this technology available to first responders. But there is more:
mobility, streaming audio and video, high-speed Internet, real-time asset awareness,
geo-location, and in-building rescue support. All this, at speeds that rival cable
modems and DSL. Combining 4G with ITS infrastructure makes both more robust. In
4G architectures, the network improves as the number of users increases. ITS offers
the network lots of users, and therefore more robustness. Think of every light pole on a
highway as a network element, a “user” that is acting as a router/repeater for first
responders traveling on those highways. Think of every traffic light as a network
element, ideally situated in the center of intersections with a 360-degree view of traffic.
This is the power of the marriage between 4G networks and ITS.

5.3 Sensors in public vehicle

Putting a chemical-biological-nuclear (CBN) warning sensor on every government-

owned vehicle instantly creates a mobile fleet that is the equivalent of an army of highly
trained dogs. As these vehicles go about their daily duties of law enforcement, garbage
collection, sewage and water maintenance, etc., municipalities get the added benefit of
early detection of CBN agents. The sensors on the vehicles can talk to fixed devices
mounted on light poles throughout the area, so positive detection can be reported in
real time. And since 4G networks can include inherent geo-location without GPS, first
responders will know where the vehicle is when it detects a CBN agent.

5.4 Cameras in traffic light

Some major cities have deployed cameras on traffic lights and send those images
back to a central command center. This is generally done using fiber, which limits
where the cameras can be hung, i.e., no fiber, no camera. 4G networks allow cities to
deploy cameras and backhaul them wirelessly. And instead of having to backhaul
every camera, cities can backhaul every third or fifth or tenth camera, using the other
cameras as router/repeaters. These cameras can also serve as fixed infrastructure
devices to support the mobile sensor application described above.

5.5 First responder route selection

Using fiber to backhaul cameras means that the intelligence collected flows one way:
from the camera to the command center. Using a 4G network, those images can also
be sent from the command center back out to the streets. Ambulances and fire trucks
facing congestion can query various cameras to choose an alternate route. Police,
stuck in traffic on major thoroughfares, can look ahead and make a decision as to
whether it would be faster to stay on the main roads or exit to the side roads.

5.6 Traffic control during disasters

4G networks can allow officials to access traffic control boxes to change inland traffic
lanes to green. Instead of having to send officers to every box on roads being
overwhelmed by civilians who are evacuating, it can all be done remotely, and
dynamically.

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6.0 ISSUES

The first issue deals with optimal choice of access technology, or how to be best
connected. Given that a user may be offered connectivity from more than one
technology at any one time, one has to consider how the terminal and an overlay
network choose the radio access technology suitable for services the user is
accessing. There are several network technologies available today, which can be
viewed as complementary. For example, WLAN is best suited for high data rate indoor
coverage. GPRS or UMTS, on the other hand, are best suited for nationwide coverage
and can be regarded as wide area networks, providing a higher degree of mobility.
Thus a user of the mobile terminal or the network needs to make the optimal choice of
radio access technology among all those available. A handover algorithm should both
determine which network to connect to as well as when to perform a handover
between the different networks. Ideally, the handover algorithm would assure that the
best overall wireless link is chosen. The network selection strategy should take into
consideration the type of application being run by the user at the time of handover.
This ensures stability as well as optimal bandwidth for interactive and background
services. The second issue regards the design of a mobility enabled IP networking
architecture, which contains the functionality to deal with mobility between access
technologies. This includes fast, seamless vertical (between heterogeneous
technologies) handovers (IP micro-mobility), quality of service (QoS), security and
accounting. Real-time applications in the future will require fast/seamless handovers
for smooth operation. Mobility in IPv6 is not optimized to take advantage of specific
mechanisms that may be deployed in different administrative domains.

Instead, IPv6 provides mobility in a manner that resembles only simple portability. To
enhance Mobility in IPv6, ‘micro-mobility’ protocols have been developed for seamless
handovers i.e. handovers that result in minimal handover delay, minimal packet loss,
and minimal loss of communication state. The third issue concerns the adaptation of
multimedia transmission across 4G networks. Indeed multimedia will be a main service
feature of 4G networks, and changing radio access networks may in particular result in
drastic changes in the network condition. Thus the framework for multimedia
transmission must be adaptive. In cellular networks such as UMTS, users compete for
scarce and expensive bandwidth. Variable bit rate services provide a way to ensure
service provisioning at lower costs. In addition the radio environment has dynamics
that renders it difficult to provide a guaranteed network service. This requires that the
services are adaptive and robust against varying radio conditions. High variations in
the network Quality of Service (QoS) leads to significant variations of the multimedia
quality. The result could sometimes be unacceptable to the users. Avoiding this
requires choosing an adaptive encoding framework for multimedia transmission. The
network should signal QoS variations to allow the application to be aware in real time
of the network conditions. User interactions will help to ensure personalized adaptation
of the multimedia presentation.

7.0 FUTURE

We do have are good reasons for 4G development and a variety of current and
evolving technologies to make 4G a reality. Highlighting the primary drivers for 4G
wireless systems are cost, speed, flexibility, and universal access. Both service
providers and users want to reduce the cost of wireless systems and the cost of

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wireless services. The less expensive the cost of the system, the more people who will
want to own it. The high bandwidth requirements of upcoming streaming video
necessitates a change in the business model the service providers use—from the
dedicated channel per user model to one of a shared-use, as-packets-are-needed
model.
This will most likely be the model service providers use when 4G systems are
commonplace (if not before). Increased speed is a critical requirement for 4G
communications systems. Data-rate increases of 10-50X over 3G systems will place
streaming audio and video access into the hands of consumers who, with each
wireless generation, demand a much richer set of wireless-system features. Power
control will be critical since some services (such as streaming video) require much
more power than do others (such as voice).
4G's flexibility will allow the integration of several different LAN and WAN technologies.
This will let the user apply one 4G appliance, most likely a cell-phone/PDA hybrid, for
many different tasks—telephony, Internet access, gaming, real-time information, and
personal networking control, to name a few. A 4G appliance would be as important in
home-networking applications as it would as a device to communicate with family,
friends, and co-workers.
Finally, a 4G wireless phone would give a user the capability of global roaming and
access—the ability to use a cell phone anywhere worldwide. At this point, the 4G
wireless system would truly go into a "one size fits all" category, having a feature set
that meets the needs of just about everyone.

8.0 CONCLUSION

The mobile technology though reached only at 3G now, 4G offers us to provide with a
very efficient and reliable wireless communication system for seamless roaming over
various network including internet which uses IP network. The 4G system will be
implemented in the coming years which are a miracle in the field of communication
engineering technology.

9.0 REFERENCE

1. http://4gmobile.com/
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d40_gci749934,00.html

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