A Novel Transmission Policy for Intelligent Reflecting Surface Assisted Wireless Powered Sensor Networks

This paper proposes a novel transmission policy for wireless powered sensor network (WPSN) assisted by an intelligent reflecting surface (IRS) to enhance the performance of energy transfer (WET) and information (WIT) with certain phase shifts. To achieve its self-sustainability, IRS collects from station support own control circuit operation. Our proposed considered WPSN is called harvest-then-transmit time switching (IRS-HTT-TS), which capable schedule slots between collection reflection modes. We provide joint design slots, power allocation as well discrete shifts WET WIT, aiming maximize system sum throughput. formulates problem mixed-integer non-linear program (MINLP), NP-hard non-convex. effectively solve this problem, we first relax it one continuous shifts, then propose two-step approach decompose original into two sub-problems. address sub-problem in closed form respect WIT. For second sub-problem, apply Lagrange dual method Karush-Kuhn-Tucker conditions derive optimal closed-form allocation, shift WET, respectively. The can be obtained quantizing values. Numerical results demonstrate effectiveness validate beneficial role comparison benchmark schemes.