lation using the Okumura-Hata model the calculations are done with two parameter sets and compared to the free space loss (see the graphs in Figure 2.11). The parameter sets are presented in Table 2.6. The distance between the BTS and MS is from 1 to 20 km in these calculations, which is also the validity range for the Okumura-Hata model. The calculation shown below is for the parameter set 2 when the distance from the BTS is 2 km: = A + B logo f - 46.30 + +[44.9 -6.55 log10(30)] log10(2) = 146.8246 (2.28) The Okumura-Hata model is valid for the frequency ranges 150-1500 MHz and 1500-2000 MHz. The range for the base station antenna height is from 30 to 200 metres, the mobile antenna height from 1 to 10 meters and the cell range, i.e. the distance between the BTS and MS, from 1 to 20 km. With Okumura-Hata loss, 1800MHz set2 Okumura-Hata loss, 900MHz set1 free space loss, 1800MHz free space loss, 900MHz 2 3 4 5 6 7 8 9 10 1112 131 141516171819 distance [km] Figure 2.11 Free space loss and Okumura-Hata propagation loss comparison Radio Wave Propagation Table 2.7 Propagation loss for different area types Area type Propagation loss [dB/decade] Free space Open area (ground reflection) Suburban Urban the additional correction factor (Lother) the Okumura-Hata model can be applied for all terrain types, meaning different morphological areas. The correction factors for each area are received as a result of model tuning including field measurements in the particular areas. Some examples of propagation loss values can be seen in Table 2.7. 2.4.2 Walfish-Ikegami Model The Walfish-Ikegami model is an empirical propagation model for an urban area, which is especially applicable for micro cells but can also be used for macro cells. The parameters related to the Walfish- Ikegami model are illustrated in Figure 2.12. The mean value for street widths (w) is given in metres and the road orientation angle (6) in degrees. The mean value for building heights (hroof) is an average over the calculation area and is given in metres. The me