Reducing Effects of Multipath Propagation With a Blind Equalizer

Sammanfattning: When transmitting data from an aircraft being prepared at the apron (the area in front of the hangar) telemetry data is transmitted to ground personnel. The transmitted data is subject to severe distortion due to multipath propagation created by the surroundings, resulting in erroneous detection. By equalizing the signal using the Constant Modulus Algorithm a significant increase in detection performance has been observed, both in simulations and tests on collected data. The most sufficient parameters were chosen after testing a set of different parameter combinations on simulations with single delays. These parameters were then used to equalize simulated multipath as well as collected data. The results show that short delays with low power can be resolved without any equalizer. Longer delays with relatively low power can be resolved using the proposed equalizer but long delays with high power cannot be resolved by the equalizer at all. The thesis shows that it is worth investigating implementation of the equalizer.