Fade Mitigation for Air-to-Ground Communication in Aeronautical Telemetry

Telemetry links were comprised of a transmit antenna mounted on the underside of fuselage and a fixed ground station equipped with a tracking antenna. Air-to- ground channel for this telemetry link can be estimated as line of sight propagation. But there is link loss observed at ground control station for certain instant of time. Possible causes of link loss in this case are due to aircraft maneuvering and fading. So analysis of various fade mitigation techniques as well as bit error rate (BER) and signal to noise (SNR) ratio performance comparison between selection diversity, equal gain combining and maximal ratio combining scheme is done. Finally bit error rate performance comparison curve between maximal ratio scheme (MRC) and Alamouti dual antenna transmission scheme is plotted, in order to find out the best scheme for fade mitigation, among all the above mentioned schemes.