Network deployment with energy efficiency optimization in IRS-assisted cell-free MIMO system

The energy efficiency and network deployment of wireless communication systems have become two main issues owing to the increasing quantity of gadgets and the limited power. Intelligent reflecting surface (IRS) is a novel technique recently proposed to increase the achievable rate and energy efficiency of multiple-input multiple-output (MIMO) wireless networks. This paper explores the deployment of IRS in a cell-free MIMO network where multiple base stations (BSs) communicate with users via IRSs. To strike the equilibrium between the achievable rate and power consumption, we explore the issue of maximizing energy efficiency by jointly designing the IRSs’ on/off mode, passive beamforming, and transmit beamforming at BSs. For resolving the coupled variables non-convex problem, we proposed a Stackelberg game algorithm for solving the sub-problems in turn, by utilizing second-order cone programming (SOCP), alternating optimization (AO), and mixed integer programming (MIP). Further, the simulation outcomes indicate that IRSs can significantly improve EE in the MIMO system. Additionally, our proposed algorithm's superiority and effectiveness in reaching the equilibrium between achievable rate and power consumption are confirmed.