Wireless Local Loop using Code Division Multiple Access

Abstract

Wireless in local loops (WLL) offers several advantages such as speedy deployment, no need for digging ducts and lower installation as well as maintenance costs compared to the conventional wired local loops. Choice of the multiple access technique is one of the very important considerations in the wireless local loops. Frequency division (FD), Time division (TD) and the Code division (CD) are the three most commonly used multiple access (MA) techniques in radio communication systems. The FDMA is not very efficient and the TDMA is currently in use in both the cellular mobile as well as in the Digital Enhanced/European Cordless Telephony (DECT) and many other WLL systems. CDMA is being used in some cellular mobile systems and is proposed to be used in 3(G) mobile systems. It has some attractive features which make it a potential candidate for WLL. The suitability of CDMA in WLL for telephony applications has been examined in this paper. Some issues related to CDMA code design, link design and system architecture for WLL applications have been proposed and simplified calculations have been made as an illustration of the idea under ideal conditions.

Indexing terms:

• CDMA
• WLL

Additional information

Notes on contributors

A K Arora

Ajay Kumar Arora passed BE (Electronics) from Madhav Institute of Technology and Science in year 1986. He passed MTech in Telecommunication & Systems Engineering from NT Khargapur in year 1999. He attended & presented a paper in National Communication Conference (NCC-99). He is presently working in a Defence Establishment.

S L Maskara

Shankar Lall Maskara graduated in Telecommunication Engineering from Bihar Institute of Technology, Sindri 1963, obtained Master of Engineering degree from the Indian Institute of Science, Bangalore in 1966 and completed his PhD degree at the Indian Institute of Technology, Kharagpur in the year 1977.

He served for one year on the faculty of BIT Sindri. In 1966, he joined the department of Electronics & Electrical Communication Engineering, IIT, Kharagpur, as a faculty member where he has been a professor since 1981.

He has been closely associated with many sponsored and consultancy research projects many of which have been successfully completed and some are on going. His research interest includes Spread Spectrum Techniques, Error Control Coding, Digital Satellite and Optical Fibre Communications and Telecommunication Switching and Networking including ATM, B ISDN, Cellular Wireless Mobile and IP based networks. He has co-authored a Textbook on Basic Electronics and has many journal and conference publications. He has guided and supervised a large number of BTech, MTech and PhD projects and theses.

He is deeply interested in teaching, planning, education and curriculum development in the area of Electronics & Telecommunication Engineering both at the undergraduate and the postgraduate levels. Being on the Board of Studies of various Institutions and Universities, he has actively contributed to their curriculam and syllabi design.

Prof Maskara has been one of the active members of the team to visualise, plan and execute the ERNET project right from its inception. He has been responsible in the planning, installation and operation of the IIT Kharagpur Telephone system and the Institute Computer Backbone Network.

He is a Fellow of the Institution of Electronics and Telecommunication Engineers and also of the Institution of Engineers(I). He is a senior member of the IEEE and life members of the ISTE and the CSI. As an active member of the Joint Telematics Group consisting of experts from the five IITs and IISc Bangalore in the area of Telecommunication, he has played a key role in starting the National Conference on Communications in the year 1995 which is held annually. He was the founding Chairman of the IEEE Kharagpur Sub-section and was also the founding Branch Counsellor of IEEE Kharagpur Student Branch. He has organized many short term courses and National and International Conference and has delivered a large number of invited and key-note lectures in the frontier areas of Telecommunication and Networking in various fora.

He served as the Head of the Department of Electronics & Electrical Communication Engineering, IIT Kharagpur and was the founder Chairman of the GS Sanyal School of Telecommunication. He was also the VSNL Chair Professor in Information Technology.