Taking into account variability in wireless communication devices performance

The quality of the radio link in a wireless communication is heavily dependent on what happens at both ends of the link, especially on the terminal side when the base station is in an elevated and free space location. In addition, these devices are often of highly varying performance and in widely variable kinds of environments, both regarding the local propagation context and the immediate (near field) medium. All this constitutes many sources of variability, which are not easily accounted for and which, in practice, are seldom considered.