Actual procedure used to establish a MW link budget in telecom?
If planning to deploy the communication scheme in a highly varied environment such as a city or town, ray-tracing techniques can be used. Ray-tracing is very computationally intensive and requires a lot of input parameters characterising the propagation environment such as a 3D topographical map of the area of concern (which can be hard to acquire).

Popular software tools used by mobile operators include the Volcano tool set from Siradel. From their website you can see that Volcano tool is used by over 100 mobile operators all over the world. In addition to this, the tool also used by the wireless research community.