CorDECT

Abstract

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

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.