Báo Cáo A study of multi-carrier transmisson for air traffic control communications in c band

A study of multi-carrier transmisson for air traffic control communications in c bandIn present times, air traffic control (ATC) systems, which are using a limited VHF band (118-137MHz), have faced several serious problems especially in system capacity and spectrum usage efficiency. In air navigation, there is a so-called C band (5030-5150MHz), which is being assigned worldwide for Microwave Landing System (MLS). In reality, one part of this band is not being used. We evaluated and realized its applicability for ATC communications, then assume to use in our next evaluations. Based on a typical propagation model in ATC, we compute Root Mean Square (RMS) delay spread and Doppler shift spread in C band. With many advantages of multi-carrier transmission technique as theoretical evaluations, we propose two system-models for ATC communications based on the combination of OFDM and conventional multiple access schemes. They are OFDM-FDMA (OFDMA) and OFDM-CDMA (MC-CDMA). From these two system-models, we carry out computer simulations for the two systems in terms of channel performance. Our results show that, OFDMA is the most promising candidate for ATC communications in the future. This model deserves the striking selection for the advanced air-ground digital link that should be considered in ATC communications.