Random Rotation-based Low-Complexity Schemes for Intelligent Reflecting Surfaces
Constantinos Psomas, Ilias Chrysovergis, Ioannis Krikidis
Abstract
The employment of intelligent reflecting surfaces (IRSs) is a potential solution to increase the spectral and energy efficiency of wireless networks. The passive operation of their elements and the fact they can be deployed on any flat surface, makes them ideal for future wireless networks. However, the passive operation of their elements, incurs limitation on their capabilities. In this paper, we propose two low-complexity and energy efficient techniques for IRS-aided communications, namely, a coding-based and a selection-based scheme, both based on random phase rotations. In particular, the coding-based scheme uses time-varying random phase rotations to produce a time-varying channel. The selection-based scheme, selects and activates a partition of the IRS elements at each time slot based on the received signal power at the destination. Analytical expressions for both schemes are derived and the achieved performance gains are demonstrated. Furthermore, it is shown that both schemes provide full diversity order.