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.