Performance Analysis of Active Large Intelligent Surfaces (LISs): Uplink Spectral Efficiency and Pilot Training

Large intelligent surfaces (LISs) constitute a new and promising wireless communication paradigm that relies on the integration of massive number antenna elements over entire man-made structures. The LIS concept provides many advantages, such as capability to provide reliable space-intensive communications by effectively establishing line-of-sight (LOS) channels. In this paper, system spectral efficiency (SSE) an active is asymptotically analyzed under practical environment with well-defined uplink frame structure. order verify impact SSE pilot contamination, multi-LIS studied theoretical bound its performance derived. Given bound, optimal training length for systems subjected contamination characterized and, subsequently, devices need be serviced in maximize Simulation results show derived analyses are close agreement exact mutual information presence large antennas, achievable limited effect intra/inter-LIS interference through LOS path, even if equipped infinite antennas. Additionally, obtained proposed scheduled shown reach one via brute-force search solution.