What is fading in wireless communication?

Fading is the variation in signal strength over time and/or location due to changes in the propagation environment. Main types include: Large-scale fading (path loss and shadowing from obstacles), and Small-scale fading (rapid fluctuations due to multipath propagation). Multipath fading occurs when signals arrive via multiple paths with different delays, causing constructive or destructive interference. Rayleigh fading describes conditions without a dominant line-of-sight path, while Rician fading includes a strong direct component. Fading mitigation techniques include diversity, equalization, and OFDM.