Capacity of Wireless Channels Under Transceiver Hardware Impairments and Adaptive Transmission Techniques

We provide an analytic framework for the capacity of adaptive transmission techniques, taking into account both generalized fading channels and Gaussian-distributed transceiver hardware impairments (THI). We derive exact expressions for the capacity of optimal power and rate adaptation, optimal rate adaptation with constant power, channel inversion with fixed rate, and truncated channel inversion with fixed rate. These expressions are general enough to cover a wide range of wireless channels. Due to the high susceptibility of high-data-rate terahertz (THz) communications to THI, we apply our results to investigate the capacity of THz communication systems and confirm the validity of our approach using numerical simulations.