# IRS, LIS, and Radio Stripes-Aided Wireless Communications: A Tutorial
###### Abstract  
This is a tutorial on current techniques that use a huge number of antennas in intelligent reflecting surfaces (IRS), large intelligent surfaces (LIS), and radio stripes (RS), highlighting the similarities, differences, advantages, and drawbacks. A comparison between IRS, LIS, and RS is performed in terms of the implementation and capabilities, in the form of a tutorial. We begin by introducing the IRS, LIS, and RS as promising technologies for 6 G wireless technology. Then, we will look at how the three notions are applied in wireless networks. We discuss various performance indicators and methodologies for characterizing and improving the performance of IRS, LIS, and RS-assisted wireless networks. We cover rate maximization, power consumption reduction, and cost implementation concerns in order to take advantage of the performance increase. Furthermore, we extend the discussion to some cases of emerging use. In the description of the three concepts, IRS-assisted communication was introduced as a passive system, considering the capacity/data rate, with power optimization being an advantage, while channel estimation was a challenge. LIS is an active component that goes beyond massive MIMO; a recent study found that channel estimation issues in IRS had improved. In comparison to IRS, capacity enhancement is a highlight, and user interference showed a trend of decreasing. However, power consumption due to utilizing power amplifiers has restrictions. The third technique for increasing coverage is cell-free massive MIMO with RS, with easy deployment in communication network structures. It is demonstrated to have suitable energy efficiency and power consumption. Finally, for future work, we further propose expanding the conversation to include some cases of new uses, such as complexity reduction; design and simulation with LDPC code could be a solution to decreasing complexity. the flexible multipath publication environment for better quality, but it has not been able to manage the environment itself. An IRS might be used to construct a programmable and controllable intelligent radio environment. The metasurface structure is vast and very thin, made of dielectric or metal. These metasurfaces, which have a unique physical structure, contain several passive sub-wavelength dispersion components. Software may regulate the component to alter the electromagnetic (EM) parameters of the reflected radio frequency (RF) signals, such as phase shift [1]. A unified phase control of all the scattering components allows for flexible real-time modification of the reflected radiation pattern of incoming RF signals, providing new degrees of freedom for improving the overall wireless network performance [4]. In contrast, the large intelligent surface (LIS) was used to describe enormous active antenna arrays that were similar to the massive MIMO (mMIMO) concept, but much larger [5]. As a result, a LIS creates, transmits, and receives signals. The arrays are not only large but also comprise very small pieces [6]. This allows them to manipulate electromagnetic waves on the surface nearly indefinitely. The LIS concept can be seen as a larger version of traditional, huge MIMO systems. Intelligent surfaces are physical surfaces that are, in theory, electromagnetically enabled surfaces, meaning that each part of the surface may broadcast and receive electromagnetic waves. Being able to control these fields with great accuracy makes it possible to concentrate energy in three-dimensional space so that it can be sent and received [7]. Therefore, the surfaces will introduce whole new possibilities for communications, as well as sensing and controlling the electromagnetic environment. Intelligent surfaces are the inevitable evolution of the mMIMO concept taken to its logical conclusion. Massive MIMO has been proven to offer several benefits, but only limited efforts have been made to prevent harmful effects from a base station, with multiple antennas that use surfaces throughout the physical area as antennas [8].