Estimation of TDMA and CDMA capacities for an air-to-ground communication system

We estimate capacities of code-division multiple access (CDMA) and time-division multiple access (TDMA) systems when applied to an air-to-ground/ground-to-air (AG/GA) environment. Our analysis is based upon a regular cellular arrangement of ground stations (bases), as in the land-mobile environment, and uses waveforms based upon current cellular standards. Two of the most crucial parameters for capacity estimation, unique for the air-to-ground environment, are the outside-cell interference factor for CDMA and the frequency re-use factor for TDMA. These are computed, using a quasi-two-dimensional (2D) analysis, for average and worst-case conditions, taking into account radio propagation effects at VHF/UHF. We also investigate variations from conventional system operational modes: half-duplex for TDMA, and 1/3 frequency re-use for CDMA. We provide capacity estimates vs. cell size, and show that (as in the cellular case), capacity depends upon the many available system parameters, in addition to cell size