In this work, we present a unified approach to predict the total path loss in various indoor communication links, taking into account the new analytical methods of the derivation of the fading phenomenon along corridors and between floors. We take into account the stochastic method of slow and fast fading estimations, caused by diffraction and multipath phenomena, respectively. The statistical parameters required for statistical description of the diffraction and multipath phenomena, such as the standard deviations of the signal strength due to slow and fast fading are obtained from the corresponding measurements. Based on strict and completed path loss prediction, an algorithm of link budget performance is presented for different scenarios of radio propagation within indoor communication links. Results of proposed unified approach are compared with the analytical model (Bertoni's) and the empirical model (Rappaport's), which are well-known and usually used in link budget design in various indoor environments The results are also compared with measurements carried out for different propagation scenarios, along corridor and between floors, occur in the indoor communication channels. A better agreement with experimental data is obtained compared with the models in consideration.