Comparative Analysis of OTFS and OFDM for UAV Assisted Wireless Network

This paper provides a comparative analysis of channel estimation for unmanned aerial vehicle (UAV)-assisted wireless networks, focusing on orthogonal time frequency space (OTFS) and orthogonal frequency division multiplexing (OFDM) techniques. UAV poses a major challenge in channel estimation due to the high-speed mobility of the receiver that causes the Doppler effect. OTFS is an emerging modulation technique to handle high-speed scenarios. OFDM has been widely adopted in wireless communication systems for its ability to support high data rate transmission, offer efficient bandwidth utilization, and maintain robustness against multipath delay spread. However, it is less effective when a receiver is moving at high speeds. The proposed work utilizes least square channel estimation in combination with OTFS and OFDM for a moving receiver (UAV) for 16-QAM modulation to understand the performance in terms of bit error rate (BER), outage probability, and normalized mean square error (NMSE). We analytically prove that OTFS outperforms OFDM and provides better BER, outage probability, and NMSE performance at high speeds.