Three-dimensional cellular systems for aeronautical mobile radio communications

A new technique for designing three-dimensional cellular systems for VHF air/ground communications is proposed to solve the problem of frequency congestion for air traffic control (ATC) and flight services. In VHF air/ground communication systems, a radio line of sight (RLOS) between the aircraft and ground station must exist. The frequency reuse distance is reduced by using the radio horizon to block cochannel interferences. In the proposed system, cells of different sizes to cover different altitude ranges are separated by different reuse distances. With nine groups of channels, the altitude range from 740 ft to 45000 ft can be covered without interference. The proposed system utilizes the spectrum efficiently by covering a certain airspace according to a well-organized plan with the minimum number of frequency channels and cell sites. Thus, it has more frequency reuse than the current systems