Studies on the performance enhancement of MC-CDMA system through site diversity techniques

Abstract

Communication has visited various trends and stages over the past few decades. Global system for mobile communication (GSM) a second generation (2G) technology, which was introduced in early 1990s , is running out of bandwidth. This has led to its evolution into third generation (3G) networks with general packet radio service (GPRS) and EDGE based networks as milestones. Although cellular phones and pagers revolutionised communication, the next few years promise the deployment of enhanced wireless communication devices. These future technologies are targeted at providing very high-rate communication anywhere and anytime. Researchers now realise the need to develop a technology to handle very high rate multimedia traffic, which will not only be able to support the traffic, but also provide this service for a mobile user moving at a high speed. This technology is certainly beyond 3G and can be classified as a fourth generation (4G) technology. The field of mobile radio communications aspires to support high data rate applications such as image and video. However, the ability to achieve high bit rates at low error rates over wireless channels is severely restricted by the frequency selectivity of channels used by multiple propagation paths with different time delays. With conventional code division multiple access (CDMA), resistance to fading is achieved by spreading the signal energy over a larger bandwidth than necessary, to contain the user signal. However, in the process of providing resistance to deep fades, the signal is affected by delay spreads to a greater extent, and experiences considerable inter chip interference (ICI). Recently, wide-band CDMA