Multiband OFDM-Based THz Wireless Communication System

This paper presents an experimental investigation of a multiband orthogonal frequency division multiplexing (OFDM) system for terahertz (THz) communication through various wireless carrier frequencies in the sub-THz band. The proposed system employs 3 bands of 2 GBaud/s signal to transmit data in parallel over 150 - 300 GHz sub-THz frequency bands. It further increases spectral efficiency to three times higher than usual OFDM in THz wireless transmission. An IM/DD (intensity modulation and direct detection) scheme is employed to meet the requirements of B5G commercialized applications, while avoiding the need for a local oscillator, thereby reducing the associated costs. QPSK, 8-QAM, and 16-QAM formats are investigated here. The BER performance indicates that overall 6 GBaud/s in QPSK format can be achieved through 250 GHz carrier frequency under 20% FEC limit over 1-meter transmission wireless distance. The proposed approach provides the potentials in the flexible OFDM sub-band allocation with meter-level link distance and cost-effective THz wireless communication system.