Mitigating blockage of transmission and reception due to rotor blades in air-to-air data link using single-carrier block modulation

In air-to-air data links such as helicopter-satellite communications, single rotor UAV (SR-UAV)-satellite communications, and inter SR-UAVs communications blockage of the data transmission or reception due to rotor blades is prevalent. The blockage incurs a loss in carrier frequency synchronisation and data throughput. This paper proposes a novel system and waveform design, based on a judicious choice of time-diversity-based single-carrier block modulation with cyclic prefix. The proposed waveform is highly reliable, power and bandwidth efficient. Time diversity mode and appropriate receiver algorithms enable highly reliable capture of all data, and data packets can be delivered in order to the next layer. Low Peak to Average Power Ratio (PAPR) is ensured by using single carrier block modulation. Accurate synchronisation is achieved at low SNR and even at negative SNR with high detection probability by adding a novel step to the popular Schmidl-Cox algorithm. Proper tracking of the frequency offset error is ensured over each frame. The timing synchronisation symbols provide phase tracking, and so the error rate can be kept low over the entire frame.