Joint Beamforming and Deployment Design for IRS-aided Energy Harvest IoT Network

In this paper, we propose a transmission design scheme for the simultaneous wireless information and power transfer (SWIPT) in the intelligent reflecting surface (IRS) aided multi-user interference channel (IFC). Our goal is to maximize the harvested energy of all receivers by jointly optimizing the transmit and reflective beamforming vectors as well as the location of the IRSs while guaranteeing the rate of each user, deployable region of each IRS, and total transmit power constraints. The formulated optimization problem is hard to be solved due to the non-convex coupled of the variables related with location and beamforming vectors as well as the infinite number of constraints. To overcome the difficulty, we first design the location of IRSs by decoupling the larger-scale and small-scale fading of the reflective channels with the local region assumption. Then, based on this, we transform the transmit and reflective beamforming optimization problem into the second-order cone program (SOCP) and the relaxed semi-definite program (SDP) problems, which are convex and solved by utilizing the conventional interior point approach. Numerical results report that the gain is improved by optimizing the location of IRSs.