Efficient Smart Antenna Systems (4G) For CDMA Wireless Communication

Today, mobile communications play a central role in the voice/data network arena. With the deployment of mass scale 3G just around the corner, new directions are already being researched. In this paper we address about the 4 G mobile communications. The Fourth Generation (4G) Mobile Communications should not focus only on the data-rate increase and new air interface.4G Mobile should instead con-verge the advanced wireless mobile communications and high-speed wireless access systems into an Open Wireless Architecture (OWA) platform which becomes the core of this emerging next generation mobile technology. Based on this OWA model, 4G mobile will deliver the best business cases to the wireless and mobile industries,i.e.cdma2000/WLAN/GPRS 3-in-1 product, WCDMA/OFDM/WLAN 3in-1 product, etc. The advent of 4G wireless systems has created many research opportunities. The expectations from 4G are high in terms of data rates, spectral efficiency, mobility and integration. Orthogonal Frequency Division Multiplexing (OFDM) is proving to be a possible multiple access technology to be used in 4G. But OFDM comes with its own challenges like high Peak to Average Ratio, linearity concerns and phase noise. This paper proposes a solution to reduce Peak to Average Ratio by clipping method. With a number of 3G systems using CDMA as the preferred transmission scheme, extensive research has been done into ways of improving performance in a CDMA system. To this end, a lot of research has been done in coding, modulation, handoff protocols and so on. One of the avenues of possible performance improvement that has not received as much attention is the use of multiple antennas at the base station (and possibly at the mobile handset as well). Multiple antennas can be used for beam steering ,diversity combining,range improvement,reduction in interference etc for obtaining performance gains, thus leading to the concept of Smart Antennas