Multiuser Long-Distance Sub-THz Wireless Communication

In this article, we present the first point-to-multipoint (P2MP) subterahertz (THz) wireless communication link capable of simultaneously transmitting data to multiple users over several meters at tens of gigabits per second (Gbps). The sub-THz wireless link employs an optoelectronic transmitter that generates digital subcarriers by modulating a single free-running laser with a high-bandwidth electro-optic inphase and quadrature modulator. A unitraveling-carrier photodiode downconverts the transmitted signal from the optical to the sub-THz domain, and the signal is transmitted by a lens-integrated leaky-wave antenna, offering a gain of up to 30 dBi and a wide beam-steering range of approximately 51° in the horizontal plane. The optoelectronic transmitter can simultaneously address multiple receiver units, i.e., users, hence enabling efficient multiuser operation. A sub-THz electronic receiver unit operating from 280 to 320 GHz is used for reception. In a proof-of-concept experiment, the sub-THz wireless link is implemented in a lecture hall scenario with one transmitter and two receiver units. The distance between the transmitter and receivers is 16 m, with the two receivers having a maximum spacing of 3.3 m. Measurements have been conducted for single-, dual-, and up to four-user configurations using quadrature phase-shift keying and 16-quadrature amplitude modulation modulation schemes. To the best of the authors' knowledge, record-high data rates of up to 80 Gbps for a single user, 40 Gbps for dual users, and 20 Gbps for four users are demonstrated for the first time in a sub-THz P2MP system.