This paper examines the integration of Intelligent Reflecting Surfaces (IRS) in beyond 5G (B5G) communication networks, where the IRS reflects signals with adjustable phase shifts. By optimizing these phase shifts, called passive beamforming, substantial improvements in communication performance can be achieved. We maximize energy efficiency in the uplink communication, utilizing the IRS. However, including an IRS introduces complexities, particularly in channel estimation. To address this, we examine two innovative approaches to minimize the channel estimation overhead: the first leverages a grouping strategy for the reflecting elements. In contrast, the second approach utilizes positioned-based phase optimization. Simulation results confirm that the IRS significantly enhances energy efficiency compared to the traditional system.