In-band transition of a nationwide air/ground radio system from an analog to a digital architecture

The Next-Generation Air/Ground (A/G) Radio Communications System (NEXCOM) will provide a digital voice and data capability for air traffic control in USA airspace. The nationwide transition from today´s all-voice analog system to NEXCOM will take several years. Since digital interference characteristics differ markedly from those of analog radios, most A/G radio circuits will need to change their operating frequencies when they are converted to NEXCOM, to avoid RF interference with neighboring circuits. The size and complexity of the system make it a challenging task to identify an incremental sequence of frequency changes that will enable a smooth, gradual, and cost-effective transition. In this paper, we present simulation results demonstrating the feasibility of a nondisruptive incremental transition to NEXCOM and identify specific measures for reducing the complexity of the transition and, thus, its overall cost.