omponents are taken into account, but in this case a line-of-sight component also exists. Supposedly this fading can be modelled using the Rician distribution. 2.4.1 Okumura-Hata Model The Okumura-Hata model is a well-known propagation model, which can be applied for a macro cell environment to predict median radio signal attenuation. Having one component the model uses free space loss. The Okumura-Hata model is an empirical model, which means that it is based on field measurements. Okumura performed the field measurements in Tokyo and published results in graphical format. Hata applied the measurement results into equations. The model can be applied without correction factors for quasi-smooth terrain in an urban area but in case of other terrain types correction factors are needed. The weakness of the Okumura-Hata model is that it does not consider reflections and shadowing. The parameter restrictions for this model are: Frequency f: 150-1500 MHz, extension 1500-2000 MHz Distance between MS and BTS d: 1-20 km Transmitter antenna height Hb: 3-200 m Receiver antenna height Hm: 1-10 m The Okumura-Hata model for path loss prediction can by written as (2.23) where f is the frequency (MHz), Hb is the base station antenna height (m), a(Hm) is the mobile antenna correction factor, d is the distance between the BTS and MS (km) and Lother is an additional correction factor for area type correction. The correction factor for the MS antenna height is represented as follows for a small or medium sized city: (2.24) and for a large city: f < 200 MHz a(Hm) (2.25) 4.97: f = 400 MHz where Hm is the MS antenna height: 1<Hm < 10 (Hm in metres) (2.26) Radio Network Planning and Optimisation Table 2.6 Parameter set for Okumura-Hata calculations Parameter set 1 Parameter set 2 City type Small/medium city Large city Frequency f 900 MHz 1800 MHz BTS height MS height Hm 1.5 m 1.5 m 69.55 46.30 26.16 33.90 The parameters A and B are dependent on the frequency as follows: 2000 MHz (2.27) = 1500 2000 MHz In an example of the path loss calcu