Chapter: Capita Selecta
Multipath reception causes rapid fluctuations of the received signal power, whereas shadowing is experienced as a slow amplitude effect. Adaptive transmit power control can mitigate the adverse effects of individual shadowing to some extent. Since most mobile networks are interference-limited rather than noise-limited, interfering signals are likely to produce substantially greater adverse collective impact if adaptive power control is used to overcome shadowing on their own transmission path. Mobile systems must live with signal fluctuations during transmission. Because of high demands on spectrum efficiency, extensive frequency re-use and mutual interference must be accepted. This means that the classical system analysis inspired by the stationary AWGN channel of conventional information theory may not be applicable.