CDMA Concept in The Telecommunication Field

Introduction

Access network, the network between local exchange and subscriber, in the Telecom Network accounts for a major portion of resources both in terms of capital and manpower. So far, the subscriber loop has remained in the domain of the copper cable providing cost effective solution in past. Quick deployment of subscriber loop, coverage of inaccessible and remote locations coupled with modern technology have led to the emergence of new Access Technologies. The various technological options available are as follows:

1. Multi Access Radio Relay
2. Wireless In Local Loop
3. Fibre In the Local Loop

Wireless In Local Loop (WILL) Fixed Wireless telephony in the subscriber access network also known as Wireless in Local Loop (WLL) is one of the hottest emerging market segments in global telecommunications today. WLL is generally used as "the last mile solution" to deliver basic phone service expeditiously where none has existed before. Flexibility and expediency are becoming the key driving factors behind the deployment of WILL.

WLL shall facilitate cordless telephony for residential as well as commercial complexes where people are highly mobile. It is also used in remote areas where it is uneconomical to lay cables and for rapid development of telephone services. The technology employed shall depend upon various radio access techniques, like FDMA, TDMA and CDMA.

Different technologies have been developed by the different countries like CT2 from France, PHS from Japan, DECT from Europe and DAMPS & CDMA from USA. Let us discuss CDMA technology in WILL application as it has a potential ability to tolerate a fair amount of interference as compared to other conventional radios. This leads to a considerable advantage from a system point of view.

Conclusion Hence we see that use of common frequency, multipath rake receiver, power control & variable bit rate vocoding and soft hand-off features of CDMA give us the benefits of no frequency planning, larger capacity, flexibility along with high performance quality.