Preliminary Studies on the Large Intelligent Surfaces Efficiencies Under Different Channels

This work investigates the impact of the channel model, and power allocation on the performance of a system employing Large Intelligent Surfaces (LIS). Most of the previous studies have considered the energy efficiency of such systems under the influence of Rayleigh channels and Zero-Forcing (ZF) precoding. We present results for Rice channels and Matched Filter (MF) receiver showing a surprising reduction in energy efficiency. We also derive an accurate approximation for spectral efficiency when the equal power allocation strategy is employed. According to our simulations, a loss of 6 dB is observed when the symbols are transmitted with the same power.