Overall Transmission Rate of 41.6 Gbit/s-0.22 THz OFDM Upstream–Downstream Real-Time Transceivers Facing Over-500 m Communication

In the practice of terahertz upstream and downstream systems, the inconsistency of up/downstream channels and terahertz frontends, unpredictable nonideality of terahertz transceivers, and crosstalk between channels lead to short communication range and limits application scenarios of terahertz communication systems. In this article, an all-solid-state terahertz full-duplex upstream and downstream communication systems working in the 220 GHz band is proposed with a 630 m communication distance. Frequency division multiplexing and orthogonal frequency division multiplexing are employed. Terahertz frontend and real-time demodulation baseband circuit are designed, and a debugging algorithm for power distribution in bidirectional communication systems is proposed, which is capable of finding the feasible solution of the furthest distance of bidirectional communication system in the premise of unclear performance of radio frequency frontend and baseband systems. The system performance and debugging algorithm are verified in the experiment. The field test shows a communication distance of 630-m under the communication speed of 20.8 Gbit/s per channel, with a bit error rate is less than
$10^{-10}$
, which supports real-time bidirectional noncompression-4 K video transmission at the same time. The estimated maximum communication distance of the system can exceed 1 km, and the difference in the estimated maximum communication distance between upstream and downstream is less than 7%.