This document discusses diversity techniques for wireless communication. It aims to reduce fading, a major impairment in wireless channels. Diversity techniques involve transmitting multiple replicas of a signal over different fading channels and combining them at the receiver. This reduces the probability that all signals will fade simultaneously. Different diversity techniques include temporal, frequency, and spatial diversity. Spatial diversity using multiple transmit and receive antennas is most popular as it provides a more robust communication without additional power or bandwidth requirements. Diversity combining at the receiver is used to optimize the received signal-to-noise ratio.