und reflection is clearly present, MO can be estimated from the angle of arrival of the reflected ray in standard propagation conditions. 2. Calculate the nonselective reduction parameter r from [150(8/S2 + 30] + 0.963 for q > 1 (3.67)* where (3.68)* Transmission Network Planning and Optimisation 8 = angular separation between the two patterns E = elevation angle of the upper antenna (positive towards the ground) S = half-power beamwidth of the antenna patterns 3. Calculate the nonselective correlation parameter Q0 from (3.69)* 4. Calculate the multipath activity parameter n as calculated above in Equation (3.57) 5. Calculate the nonselective outage probability from (3.70)* 6. Calculate the square of the selective correlation coefficient from (3.71)* 7. The selective outage probability Pds is found from (3.72)* where Ps is the nonprotected outage as calculated in Equation (3.51). 8. The total outage probability P is calculated as (3.73)* Other hydrometers such as snow, hail, cloud and fog droplets have some impact on the performance of microwave links. However, attenuation due to moist snow is less than the equivalent rainfall, while wet snow has an attenuation approximately double the equivalent rainfall and watery snow has an attenuation triple the equivalent rainfall. Hail, which is a mixture of water, air and ice, has an impact at frequency of 34 GHz, with losses going as high as 6 dB/km. Cloud and fog droplets with a radius less than 0.1 mm attenuate the signal by 0.3 dB/km at a frequency of 40 GHz. 3.6 Interface Planning Once the quality issues have been addressed in link planning, capacity planning is the next step. In the GSM networks, Abis and Ater interface planning helps to define the equipment required, especially microwave radios. Through this lanning/dimensioning exercise, the number of 2 Mbps links can be determined, which further helps to define the type of radios. To dimension the interfaces, the following aspects should be kept in mind: no blocking between the BTS and BSC; no blocking between th