Now-a-days the requirements of wireless communication are to have high voice quality, high data rates, multimedia features, lightweight communication devices etc. But the wireless communication channel suffers from much impairment .One of them is fading which is due to the effect of multiple propagation paths, and the rapid movement of mobile communication devices. In a typical wireless communication environment, multiple propagation paths often exist from a transmitter to a receiver due to scattering by different objects. Signal copies following different paths can undergo different attenuation, distortions, delays and phase shifts. So, this is necessary to reduce the problem of fading, but not at the cost of extra power or additional bandwidth. One effective solution is proposed for wireless system named diversity, with out the requirement of power or extra bandwidth. This paper discusses about the characteristics of fading channels and a broad classification of various diversity techniques. To overcome the effect of fading various combining techniques are used at the receiver to get good signal at the receiver for improving the overall performance of the communication system. They are explained using very simple mathematics