A case for OFDM in ultra-broadband terahertz communication

Terahertz (THz) Band communication is envisioned as one of the leading technology to meet the exponentially growing data rate requirements of emerging and future wireless communication networks. Although prior works on THz channel measurement capture large scale fading effects, like free space path loss and atmospheric absorption, they do not show the overall effect on the received signal due to additional non-linearity from experimental hardware. In this work, we perform over the air experiments in ultra-broad THz bandwidth (10 GHz) that reveals that the received signal undergoes frequency selective fading due to hardware imperfections. This motivates us to utilize orthogonal frequency division multiplexing (OFDM) in indoor short range ultra-broadband THz communication. To experimentally show its efficacy, we compute the coherence bandwidth of the system, which is less than the full bandwidth. We derive optimal parameters for OFDM for our hardware setup and perform over-the-air experiments to achieve 42 Gbps physical layer data rate over an effective bandwidth of 8.125 GHz.