# IRS, LIS, and Radio Stripes-Aided Wireless Communications: A Tutorial
## 2 Several Promising Techniques: IRS, LIS, and Radio Stripes
### Categorizing Recent Studies on Radio Stripes  
The RS concept represents the implementation of a viable CF mMIMO network. It is made up of a stripe that is linked to a CPU, to which a huge number of antennas are connected and collaborate phase-coherently. The APs are stacked one on top of the other on the same cable. This lets them synchronize, transfer data, and get power over a single link, getting rid of the requirement for separate fronthaul links between each AP and its CPU [9; 37].  
Radio stripes can be used anywhere and at any time (Figure 3[14]). For busy environments such as stadiums, stations, and shopping malls, a cell-free technique of deployment based on radio stripes was also suggested [38]. Many APs are connected by a single fronthaul cable, which also serves as a means of data transport, power transmission, and synchronization. A consecutive procedure, dubbed \"normalized-MMSE\" (N-MMSE) was published for the radio stripe cell-free technique, which creates nearby Aps. The striped system consists of numerous antenna PBs with maximum transmit energy restrictions that coherently beamform power signals towards devices that utilize CSI acquired through up  
\begin{table}
\begin{tabular}{c p{284.5 pt}} \hline \hline
**Reference** & **Main Contribution** \\ \hline
[6] & One of the disadvantages of the implementation of the LIS is the complexity of the panels. This paper offers a method for omitting the complexity involved in managing the set of activated panels. \\ \hline
[7] & It is demonstrated that when terminal density grows, it is preferable to use smaller panels and, as a result, more outputs per m\({}^{2}\). \\ \hline
[8] & This research investigates the capabilities of single-antenna terminals being connected with huge antenna arrays installed on surfaces. That is, the entire surface is used as an IRS array. If the surface area is high enough, the received signal after matched filtering (MF) can be well represented by the intersymbol interference (ISI) channel. \\ \hline
[16] & The best user assignments can be efficiently obtained using classical linear assignment problems (LAPs) developed based on the pleasant property of effective inter-user interference suppression of the LIS units. \\ \hline
[27] & The capacity and utility of the surface area are both reduced with HWI due to the greater effective noise level induced by the HWI. A distributed LIS system can be implemented by dividing it into numerous small LIS units, where the effects of the HWI can be considerably reduced due to the smaller surface area of each unit. \\ \hline
[30] & As the number of antennas increases, hardware impairments, noise, and interference from channel estimate errors and the non-line-of-sight become insignificant. This paper investigated the uplink rate in the presence of restrictions such as device-specific, spatially correlated Rician fading. \\ \hline
[32] & Coverage and positioning are discussed in this paper. \\ \hline
[33] & This paper designs a Channel estimation scheme for large LIR-assisted multi-user wireless communication systems. \\ \hline
[34] & This study discusses the implementation problems associated with the interconnection data rate in the LIS. It additionally examined the system capacity and implementation cost with various design parameters and provided design suggestions for LIS installation. \\ \hline \hline \end{tabular}
\end{table}
Table 2: Representative Overview of Recent Research on the LIS.  
link retraining and power transfer efficiency (PTE) data of the energy harvesting (EH) circuits at the user equipment's (UEs). Cutting-edge precoders are adopted that attempt to lower radio stripe transmit power and must meet tight EH specifications per UE [37].