| General Packet Radio Service (GPRS) is
an enhancement to existing GSM networks that introduces
packet data transmission, enabling "always on"
mobility. This means that users can choose to be permanently
logged on to e-mail, Internet access and other services,
but do not have to pay for these services unless sending
or receiving information. It is a new nonvoice value added
service that allows information to be sent and received
across a mobile telephone network. It supplements todays
Circuit Switched Data and Short Message Service. GPRS
is NOT related to GPS (the Global Positioning System),
a similar acronym that is often used in mobile contexts.
Quick benefits of GPRS
- Faster data speeds and "always on" mobility
- Almost instantaneous connection set-up
- Connection to an abundance of data sources around
the world, through support for multiple protocols, including
IP
- A step towards full 3G (3rd Generation) services.
For mobile operator, GPRS can be implemented by adding
new packet data nodes and upgrading existing nodes to
provide a routing path for packet data between the mobile
terminal and a gateway node. The gateway node will provide
interworking with external packet data networks for
access to the Internet and intranets.
Unique Features
GPRS has several unique features which can be summarized
as: 1. SPEED
Theoretical maximum speeds of up to 171.2 kilobits per
second (kbps) are achievable with GPRS using all eight
timeslots at the same time. This is about three times
as fast as the data transmission speeds possible over
todays fixed telecommunications networks and ten
times as fast as current Circuit Switched Data services
on GSM networks. 2. IMMEDIACY
GPRS facilitates instant connections whereby information
can be sent or received immediately as the need arises.
No dial-up modem connection is necessary. This is why
GPRS users are sometimes referred to be as being "always
connected". Immediacy is one of the advantages of
GPRS (and SMS) when compared to Circuit Switched Data.
High immediacy is a very important feature for time critical
applications such as remote credit card authorization
where it would be unacceptable to keep the customer waiting
for even thirty extra seconds. 3. NEW APPLICATIONS,
BETTER APPLICATIONS
GPRS facilitates several new applications that have not
previously been available over GSM networks due to the
limitations in speed of Circuit Switched Data (9.6 kbps)
and message length of the Short Message Service (160 characters).
These applications, described later in this white paper,
range from web browsing to file transfer to home automation-
the ability to remotely access and control in-house appliances
and machines.
SERVICE ACCESS
To use GPRS, users specifically need:
- a mobile phone or terminal that supports GPRS (existing
GSM phones do NOT support GPRS)
- a subscription to a mobile telephone network that
supports GPRS
- use of GPRS must be enabled for that user. Automatic
access to the GPRS may be allowed by some mobile network
operators, others will require a specific opt-in
- knowledge of how to send and/or receive GPRS information
using their specific model of mobile phone, including
software and hardware configuration (this creates
a customer service requirement)
- a destination to send or receive information through
GPRS. Whereas with SMS this was often another mobile
phone, in the case of GPRS, it is likely to be an
Internet address, since GPRS is designed to make the
Internet fully available to mobile users for the first
time. From day one, GPRS users can access any web
page or other Internet applications- providing an
immediate critical mass of uses.
Key Network Features
of GPRS (technical information)
PACKET SWITCHING
GPRS involves overlaying a packet based air interface
on the existing circuit switched GSM network. This gives
the user an option to use a packet-based data service.
To supplement a circuit switched network architecture
with packet switching is quite a major upgrade. However,
as we shall see later, the GPRS standard is delivered
in a very elegant manner- with network operators needing
only to add a couple of new infrastructure nodes and
making a software upgrade to some existing network elements.
With GPRS, the information is split into separate but
related "packets" before being transmitted
and reassembled at the receiving end. Packet switching
is similar to a jigsaw puzzle- the image that the puzzle
represents is divided into pieces at the manufacturing
factory and put into a plastic bag. During transportation
of the now boxed jigsaw from the factory to the end
user, the pieces get jumbled up. When the recipient
empties the bag with all the pieces, they are reassembled
to form the original image. All the pieces are all related
and fit together, but the way they are transported and
assembled varies. The Internet itself is another example
of a packet data network, the most famous of many such
network types.
SPECTRUM EFFICIENCY
Packet switching means that GPRS radio resources are
used only when users are actually sending or receiving
data. Rather than dedicating a radio channel to a mobile
data user for a fixed period of time, the available
radio resource can be concurrently shared between several
users. This efficient use of scarce radio resources
means that large numbers of GPRS users can potentially
share the same bandwidth and be served from a single
cell. The actual number of users supported depends on
the application being used and how much data is being
transferred. Because of the spectrum efficiency of GPRS,
there is less need to build in idle capacity that is
only used in peak hours. GPRS therefore lets network
operators maximize the use of their network resources
in a dynamic and flexible way, along with user access
to resources and revenues.
GPRS should improve the peak time capacity of a GSM
network since it simultaneously:
- allocates scarce radio resources more efficiently
by supporting virtual connectivity
- migrates traffic that was previously sent using
Circuit Switched Data to GPRS instead, and
- reduces SMS Center and signaling channel loading
by migrating some traffic that previously was sent
using SMS to GPRS instead using the GPRS/ SMS interconnect
that is supported by the GPRS standards.
INTERNET AWARE
For the first time, GPRS fully enables Mobile Internet
functionality by allowing interworking between the existing
Internet and the new GPRS network. Any service that is
used over the fixed Internet today- File Transfer Protocol
(FTP), web browsing, chat, email, telnet- will be as available
over the mobile network because of GPRS. In fact, many
network operators are considering the opportunity to use
GPRS to help become wireless Internet Service Providers
in their own right.
The World Wide Web is becoming the primary communications
interface- people access the Internet for entertainment
and information collection, the intranet for accessing
company information and connecting with colleagues and
the extranet for accessing customers and suppliers.
These are all derivatives of the World Wide Web aimed
at connecting different communities of interest. There
is a trend away from storing information locally in
specific software packages on PCs to remotely on the
Internet. When you want to check your schedule or contacts,
instead of using something like "Act!", you
go onto the Internet site such as a portal. Hence, web
browsing is a very important application for GPRS. Because
it uses the same protocols, the GPRS network can be
viewed as a sub-network of the Internet with GPRS capable
mobile phones being viewed as mobile hosts. This means
that each GPRS terminal can potentially have its own
IP address and will be addressable as such.
SUPPORTS TDMA AND GSM
It should be noted right that the General Packet Radio
Service is not only a service designed to be deployed
on mobile networks that are based on the GSM digital
mobile phone standard. The IS-136 Time Division Multiple
Access (TDMA) standard, popular in North and South America,
will also support GPRS. This follows an agreement to
follow the same evolution path towards third generation
mobile phone networks concluded in early 1999 by the
industry associations that support these two network
types. |