Spatial Throughput Characterization for Intelligent Reflecting Surface Aided Multiuser System

Intelligent Reflecting Surface (IRS) has been recently proposed as a promising solution to enhance the spectral and energy efficiency of future wireless networks by tuning a massive number of low-cost passive reflecting elements and thereby constructing favorable wireless propagation environment. Different from the prior works that focus on link-level performance optimization for IRS-aided wireless systems, this letter characterizes the spatial throughput of a single-cell multiuser system aided by multiple IRSs that are randomly deployed in the cell. It is shown by simulation that our analysis is valid and the IRS-aided system outperforms the full-duplex relay-aided counterpart system in terms of spatial throughput when the number of IRSs exceeds a certain value. Moreover, it is shown that different deploying strategies for IRSs/active relays should be adopted for their respective throughput maximization. Finally, it is revealed that given the total number of reflecting elements for IRSs, the system spatial throughput increases when fewer IRSs are deployed each with more reflecting elements, but at the cost of more spatially varying user rates.