Ultrafast Pulsed THz Communication

We study the problem of wireless communication over indoor pulsed terahertz (THz) channels. First, we characterize the THz channel using measurements and derive a channel model. This channel model is then implemented in a Matlab simulator that we use to study different modulation schemes. In this paper, our focus is on examining frequency-domain differential phase shift keying (FD-DPSK) modulation schemes. We show that absorption due to water vapor leads to high bit error rate (BER). To combat this, we propose adaptive modulation schemes in which, depending on the humidity level of the channel and the distance between transmitter (Tx) and receiver (Rx), the system excludes some bands of the pulsed signal from the modulation scheme. Using FD-D64PSK modulation scheme and multiple transmitters in a time division multiplexing (TDM) channel, data rates as high as 5.994 Tbit/s can be achieved when the relative humidity (RH) is 0% over a distance of 50 cm. When the RH increases to 40% and 80% data rates decrease to 5.938 Tbit/s and 5.817 Tbit/s, respectively.