pdf - International Journal of Computer Technology and Applications

Sujata Khobragade,Snehalata Barde,Rasmiprava Singh Int. J. Comp. Tech. Appl., Vol 2 (2), 327-331
ISSN:2229-6093
Hybridization of advance technologies in the field of WLAN
1 Sujata Khobragade, 2 Snehalata Barde, 3 Rasmiprava Singh,
1 NIT Raipur(C.G.) , suajtakhobragade27@gmail.com
2 NIT Raipur(C.G.), sneha.barde@yahoo.com
3 NIT Raipur(C.G.), rasmiprava.singh@gmail.com
Abstract: Wireless communication is the transfer of information over a distance without the use of
enhanced 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 wide area cellular network solutions have been around for many years.
Widespread adoption has been slow due to issues with coverage, cost, performance, and secure
remote access to business networks. The deployment of the Global System for Mobile
Communications (GSM)-based General Packet Radio Service (GPRS) has the potential to change
this situation and to provide connectivity “anytime and anywhere.” This paper reviews the
underlying GSM circuit switched technology and the packet-data capabilities added by GPRS.
Here we give the brief description of GPRS technologies and its comparision with GSM
technology.
Keywords: GSM, GPRS, Wireless, Cellular Network
,
.
I. INTRODUCTION
Wireless technology increases worker
responsiveness and productivity, but it can
also be too much of a good thing. Mobile
employees commonly carry cellular phones,
wireless laptops and personal digital
assistants so they can talk with customers
and co-workers, check voice and e-mail
messages, access enterprise network
applications and use instant messaging (IM).
Carrying several devices can be unwieldy,
and the need to check multiple mailboxes
reduces the productivity potential of all that
wireless power. Wireless wide area cellular
network solutions have been around for
many years. Widespread adoption has been
slow due to issues with coverage, cost,
performance, and secure remote access to
business networks. The deployment of the
Global System for Mobile Communications
(GSM)-based General Packet Radio Service
(GPRS) has the potential to change this
situation and to provide connectivity
“anytime and anywhere.” GPRS is a packet-based
radio service that enables “always on”
connections, eliminating repetitive and time
consuming dial-up connections. It will also
provide real throughput in excess of 40 Kbps,
about the same speed as an excellent landline
analog modem connection General Packet Radio
Service (GPRS) is a communication standard for
mobile phone net works that is designed for
efficient data transfer. GPRS, which is typically
faster than older, circuit-switched services, is not
intended for voice communication but is, instead,
tailored for activities such as email and web
browsing over the mobile network. One important
quality of GPRS is that it has the effect of being
“always on.” You do not have to dial a number in
order to access GPRS services.
2. EVOLUTION OF GSM
2G cellular telecom networks were commercially
launched on the GSM standard in Finland by
Radiolinja (now part of Elisa Oyj) in 1991. There
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Sujata Khobragade,Snehalata Barde,Rasmiprava Singh Int. J. Comp. Tech. Appl., Vol 2 (2), 327-331
ISSN:2229-6093
are several major second-generation (or 2G)
digital cellular standards used throughout
the world. The most widespread are GSM,
the Code Division Multiple Access (CDMA)
standard called cdmaOne, Time Division
Multiple Access (TDMA), and Personal
Digital Communications (PDC) used mainly
in Japan. Over the next few years, there will
be a transition to 2.5G and 3G technologies
that, in addition to voice services, will add
support for “always on” packet data access
and, eventually, new multimedia types of
wireless service. In some countries such as
the U.S., there is a complementary trend to
deploy localized wireless local area
networks (WLANs) in public places such as
hotels, airports, and cafes. These wireless
LANs allow users to access the Internet and
intranets through broadband service
providers. More than two out of three digital
cellular subscribers worldwide connect
using GSM, making GSM the dominant
worldwide standard. Additionally, a number
of major North American TDMA service
providers have decided to deploy
GSM/GPRS overlays, rather than continuing
on a separate and unique evolution path
towards 3G networks. Figure 1 shows the
evolution paths of current technologies to
2.5G and 3G.
Fig.Wide-Area Cellular Network Evolution
to 3G.
2.1 GSM Technology Characteristics
The GSM radio technology is based on 200-
kHz wide radio channels with a gross data
rate of 270 Kbps. Each radio channel is divided
into eight time slots using TDMA.
Several users can efficiently share these radio
channels. Separate radio channels are used from
the mobile devices to the network and the network
to the mobile devices through the frequency
division duplex (FDD) technique. In GSM, voice
calls are supported by sampling the user’s voice
and compressing the data using digital encoding
algorithms.GSM is currently defined for three
major frequency bands, including blocks of radio
spectrum within the 900-, 1800-, and 1900-MHz
bands. The 900- and 1800-MHz bands are the
principal bands used in Europe and Asia, and the
1900-MHz band is used in North America.North
American TDMA operators are also considering
the deployment of GSM within the 850-MHz
band as well. The 450-MHz band is used in some
Eastern European countries. There are terminal
devices that support multiple bands, allowing
them to operate in different countries and
networks.Upcoming advance technologies "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 International Telecommunication
(ITU).GPRS could provide data rates from 56
kbit/s up to 115 kbit/s. It can be used for services
such as Wireless Application Protocol (WAP)
access,Multimedia Messaging Service (MMS),
and for Internet communication services such as
email and World Wide Web access. GPRS data
transfer is typically charged per megabyte of
traffic transferred, while data communication via
traditional circuit switching is billed per minute of
connection time, independent of whether the user
actually is utilizing the capacity or is in an idle
state GPRS is a packet data overlay onto existing
GSM networks.As a global standard, it is
expected to be widely deployed on GSM
networks. Figure 2 depicts a simplified GPRS
network.
New terminal devices are required to take
advantage of GPRS. The new devices will range
from cell phones to PDAs to PC Card modems.
Some will support simultaneous connections to
packet- and circuit-switched services, and others,
nonsimultaneous connections.Still others will only
support the new packet data services.GPRS
requires an upgrade to the GSM radio network
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Sujata Khobragade,Snehalata Barde,Rasmiprava Singh Int. J. Comp. Tech. Appl., Vol 2 (2), 327-331
ISSN:2229-6093
known as the Base Station Subsystem
(BSS). This normally includes a software
upgrade to the radio
transceivers and base station control nodes.
In addition,a new hardware unit called a
Packet Control Unit (PCU) is typically
added to the BSS to manage the packet data
transfer between user devices and the GPRS
core network network.The PCU also
supports data frame retransmission and other
specific GPRS protocol functions.
2.2 Working principle of GPRS
When a user turns on a GPRS device,
typically it will automatically scan for a
local GPRS channel. If an appropriate
channel is detected, the device will attempt
to attach to the network. The SGSN receives
the attach request, fetches subscriber profile
information from the subscriber’s HLR
node, and authenticates the user. Ciphering
may be established at this point The SGSN
uses the profile information (including the
access-point name, which identifies the
network and operator) to determine which
GGSN to route to. The selected gateway
may perform a Remote Authentication Dial-
In User Service (RADIUS) authentication
and allocate a dynamic Internet Protocol (IP)
address to the user before setting up
connections to outside networks. This
process is called the “packet data profile
context activation”and the setup may vary
from one carrier to the next. It may include
additional functions like QoS management
and virtual private network (VPN) tunnel
management.When the mobile device is
powered off or moved out of a GPRS
coverage area, its context is deactivated and
the device is detached from the network.
3.Comparison between GSM and GPRS
GPRS provides faster data transfer rates, “always
on” connection, robust connectivity, broad
application support,and strong security
mechanisms.Faster Data Transfer Rates GPRS
currently supports an average data rate of 115
Kbps, but this speed is only achieved by
dedicating all eight time slots to GPRS.3 Instead,
carriers and terminal devices will typically be
configured to handle a specific number of time
slots for upstream and downstream data.
Always-On Connection
An “always on” connection eliminates the lengthy
delays required to reconnect to the network to
send and receive data. Information can also be
pushed to the end user in real time.GPRS allows
providers to bill by the packet, rather than by the
minute, thus enabling cost-effective “always
on”subscriber services.
Robust Connectivity
GPRS improves data transmission integrity with a
number of mechanisms. First, user data is encoded
with redundancies that improve its resistance to
adverse radio conditions. The amount ofcoding
redundancy can be varied, depending on radio
conditions. GPRS has defined four coding
schemes—CS1 through CS4. Initially,only CS1
and CS2 will be supported, which allows
approximately 9 and 13 Kbps in each time slot.If
an error is detected in a frame received in the
BSS, the frame may be repeatedly retransmitted
until properly received before passing it on to the
GPRS core network.
Broad Application Support
Like the Internet, GPRS is based on packetswitched
data.This means that all native IP
applications, such as email,Web access, instant
messaging, and file transfers can run over GPRS.
In addition, its faster data transfer rates enable
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Sujata Khobragade,Snehalata Barde,Rasmiprava Singh Int. J. Comp. Tech. Appl., Vol 2 (2), 327-331
ISSN:2229-6093
GPRS to accommodate higher-bandwidth
applications (such as multimedia Web
content) not suited to slower GSM dial-up
connections. GPRS is particularly well
suited for applications based on the Wireless
Application Protocol (WAP). WAP has
gained widespread acceptance in a new
breed of microbrowser-enabled phones.
Security Support
GPRS builds on the proven authentication
and security model used by GSM. At session
initiation, a user is authenticated using secret
information contained on a smart card called
a Subscriber Identity Module (SIM).
Authentication data is exchanged and
validated with records stored in the HLR
network node. GPRS enables additional
authentication using protocols such as
RADIUS before the subscriber is allowed
access to the Internet or corporate data
networks.GPRS supports the ciphering of
user data across the wireless interface from
the mobile terminal to the SGSN. In
addition, higher-level, end-to-end VPN
encryption may take place when a user
connects to a private corporate network.
GPRS Network
• Add new core network elements
• Serving GPRS Support Node
(SGSN)
• Gateway GPRS Support Node
(GGSN)
Fig The SGSN and GGSN additions
GPRS BSS
• A software upgrade is required in the
existing Base Transceiver Site (BTS).
• The Base Station Controller (BSC) also
requires a software upgrade, and the
installation of a new piece of hardware
called a packet control unit (PCU).
• The PCU directs the data traffic to the
GPRS network and can be a separate
hardware element associated with BSC.
• The PCU provides a physical and logical
data interface out of BSS for packet data
traffic.
Databases (VLR and HLR)
• All the databases involved in the network
requires software upgrades to handle the
new call models and functions introduced
by GPRS.
• The home Location Register (HLR) and
Visitor Location Register (VLR)
especially require upgrades to functionally
service GPRS.
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Sujata Khobragade,Snehalata Barde,Rasmiprava Singh Int. J. Comp. Tech. Appl., Vol 2 (2), 327-331
ISSN:2229-6093
3.) Internet protocol version 6 (IPv6), where a
visiting care-of mobile IP address is assigned
according to location and connected network.
4.) Pervasive Networks providing ubiquitous
computing: The user can simultaneously be
connected to several wireless access technologies
and seamlessly move between them.
References
The network reference model for GSM
CONCLUSION
Mobiles have become very essential part of
our everyday life. Their current development
is the outcome of various generations. In this
paper we review the various generations of
mobile wireless technology, their portals,
performance, advantages and disadvantages
of one generation over other.This field is
still full of research opportunities.In
conclusion, our survey reveals that there are
following major area of research
1. EDGE (Enhanced Data rates for
GSM Evolution)
EDGE (EGPRS) is an abbreviation for
Enhanced Data rates for GSM Evolution, is
a digital mobile phone technology.EDGE
technology is an extended version of GSM.
It allows the clear and fast transmission of
data and information. It is also termed as
IMT-SC or single carrier.
2. HSDPA (High-Speed Downlink
Packet Access)
High-Speed Downlink Packet
Access(HSDPA) is a mobile telephony
protocol, also called 3.5G (or "3½G"),
which provides a smooth evolutionary path
for UMTS-based 3G networks allowing for
higher data transfer speeds.
1.) Real wireless world with no more
limitation with access and zone issues.
2.) Wearable devices with AI capabilities.
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