Refraction is the bending of waves as they pass from one medium to another, due to a change in their speed. The phenomenon is most commonly associated with light, but can also apply to sound, or even water, waves. The most common example used when discussing refraction is a straw in water. When a straw is placed in a glass of water and viewed from the side, it appears to be broken or bent. This is due to the difference in the refractive indices of air and water. Since water is denser than air, the straw appears to bend as the light it reflects is slowed by the density of the water. This phenomenon also makes submerged objects, such as fish; look closer to the surface than they actually are. Like a rock in the glass of water looks more bent out of shape than normal. The reason behind this is that the air around the rock outside of the glass has a different density than the water inside the glass. Refraction of light is bending of light as it enters medium of different density. Reflection of light (and other forms of electromagnetic radiation) occurs when the waves encounter a surface or other boundary that does not absorb the energy of the radiation and bounces the waves away from the surface. The simplest example of visible light reflection is the surface of a smooth pool of water, where incident light is reflected in an orderly manner to produce a clear image of the scenery surrounding the pool. Throw a rock into the pool, and the water is perturbed to form waves, which disrupt the reflection by scattering the reflected light rays in all directions. Signal degradation can occur in many ways. Signal degradation can occur if you are trying to communicate over vast distance that the system was not designed for. An example of this is, if the equipment or cable becomes damaged or the antenna becomes blocked.

References
Oliviero, A., & Woodward, B.