Q 2.7 What are the advantages of geostationary orbit?
Participating ground stations do not require elaborate tracking as required by other types of orbits. Radio links and interference environment are (nearly) invariant and stable, which simplifies radio link design and inter/intra-system interference management. Small Earth stations can use fixed antennas enabling low cost receivers for mass use while large Earth stations can use simple and low-cost tracking system such as step track. The network architecture is simple.
Although geostationary satellites are said to be stationary, in practice they do move about slightly sometimes by up to 3 degrees a day in a repetitive pattern. This order of movement is easily absorbed by small antennas as used in direct broadcast receivers and small fixed receivers since satellite movements are well within their field-of-view.