Waveform Design of UAV Data Links in Urban Environments for Interference Mitigation

摘要

OFDM-based communication systems for Unmanned Aerial Vehicles (UAV) are designed predominately for high mobility scenarios with direct line of sight. The number of sub-channels used is selected to be small to mitigate the effects of inter-carrier interference (ICI) resulting from carrier frequency offset. We investigate interference effects in urban environments for quad-copter UAVs based on both ICI and inter-symbol interference (ISI), which results from multi-path scenarios. We propose that changing the number of sub-carriers used in the Air-to-Ground link improves bit error rate performance dependent upon the channel characteristics. In the presence of closely spaced buildings, a greater amount of multi-path will occur, motivating the use of more sub-carriers. A practical joint synchronizer is discussed to enable scalability of the proposed idea and characterize the source of ICI. Through the use of ray tracing models and realistic end-to-end simulations, we determine that UAV communications in urban environments benefit from adaptive sub-carrier counts to combat interference effects.