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Definition
This report describes a new wireless local loop system for rapid expansion
of telecom services developed under a joint project involving Indian scientists
form Indian Institute Of Technology, Chennai, Midas technology and Analog Devices
Inc., USA. The new system, called corDECT, is based on microcellular architecture
and uses a modest bandwidth of 20MHz to provide voice, fax, and data communication
in low as well as very high subscriber density environments. The high capacity
at a modest bandwidth is made possible without prior frequency planning through
a completely decentralized channel allocation procedure called dynamic channel
selection. This technology provides cost-effective simultaneous high quality voice
and data connectivity, a voice communication using 32Kbps ADPCM and Internet connectivity
at 35\70 Kbps. This report discusses the relevance of corDECT in the context of
current trends towards wireless systems, contrasts the microcellular architecture
of corDECT with existing wireless systems based on macrocellular architectures,
and outlines its market potential. INTRODUCTION/OVERVIEW
A new wireless local loop system to eliminate the physical connections between
telephone exchanges and subscribers has just hit the market after a two-year long
joint research effort by Indian and US engineers. The new system, called corDECT,
is said to offer significant cost-savings, rapid installation, and improved reliability
over traditional connections based on copper cables. It is based on a microcellular
architecture that is said to offer cost and operational advantages over wireless/mobile
telephone systems based on macrocellular architectures. The corDECT system is
based on the European Digital Enhanced Cordless Telecommunications standard that
uses a modest bandwidth of 20MHz in the 1880-1900 MHz range and does not require
prior frequency planning necessary in conventional mobile cellular systems. The
corDECT technology uses relatively low-cost, easy-to-install subsystems and can
serve relatively high subscriber density environments -several thousands of subscribers
per square kilometer. Four Indian companies have bought the technology for domestic
manufacture. Its developers believe there is a large market potential in the Asia-Pacific
region and in other developing countries. This report will describe the CorDECT
wireless local loop system and its subsystems and compare the microcellular architecture
of corDECT with macrocellular architectures employed in many wireless telephone
systems. Need for wireless local loop system:
The telephone and the Internet have changed the way we deliver and receive information
and the way we use it for business, entertainment, planning and living. Unfortunately,
only 15 percent of the world's population is believed to have access to the Internet.
And more than 80 percent of people in the world are believed to have never even
heard a dial tone. This Digital divide -between the information 'haves' and 'have
nots' -is widening. In India, the problem is acute. Among 1000 million people.
There are fewer than 35 million people; there are fewer than 35 million phones
connections and around two million Internet connections. There is an urgent need
to bridges the gap.
The biggest reason for is high cost. The existing per
line cost of a telephone network is Rs.30, 000, which most people in India cannot
afford; this has to be reduced by a factor of three to four. In order to reduce
the cost, we must consider the factors responsible for overall system cost. The
telecom network consists of two components.
1.A
backbone network consisting of routers, switches and interconnection of exchanges
and routers, including intercity and international connections.
2.An access
network that includes the connection of the exchange to the office and home.
Fortunately, the cost of the backbone network
is reducing rapidly each successive year with improvements in technology. In order
to reduce overall costs. There is a need to focus on the cost of the access networks-
that is, the cost of the local loop. By reducing this cost, it is possible to
reduce overall per line cost by Rs12, 000 to Rs.16, 000.
For nearly a
century, these connections have relied on pairs of copper cables. But laying out
wired local loops has been an expensive, time-consuming process that also requires
detailed planning and intensive labor costs. According to a projection by the
International Telecommunications Union, developing countries alone will require
35-million pair kilometers of copper cable by the turn of the century just to
maintain existing waiting lists. The increasing cost of copper, the operational
problems associated with wired lines, and the demands for mobility are factors
fueling the move towards wireless local loops.
Importance
of CorDECT in present scenario:
Internet connections today, for the most
part, use a modem to connect a computer to a telephone line. In this case, Internet
traffic passes through the telecom network, which overloads the telecom network.
It is necessary to develop an access network technology, which separates Internet
data form the voice and prevent it from interfering with the telephone network.
This would also make it possible to use the telephone and the Internet on the
same line simultaneously.
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