# On the Performance of Partial LIS for 6G Systems
## 3 Simulation Results and Analysis  
This section shows the performance of the LIS and partial LIS, in terms of bit error rate (BER), as a function of \(E_{b}/N_{0}\). \(E_{b}\) stands for the energy of the transmitted bits, and \(N_{0}\) is the one-sided power spectral density of the noise. Results are obtained through Monte Carlo simulations, using SC-FDE block transmission techniques. In the simulations, the locations of the users are randomly selected within the compartment. The channel has five multipath components (an LoS and four reflected rays in the walls) without fading, and the power of each multipath component is given by the propagation conditions (overall propagation length plus reflection losses). Ground-reflected paths are more likely to be blocked and/or attenuated by the antennas' radiation pattern and have a lower reflection factor (for example, if a mat or a carpet is employed). It is worth noting that the number of reflections does not seem to have a significant effect on the performance and does not affect our main conclusions (the conclusions are essentially the same even with second-order reflections). In the Monte Carlo simulations, we considered \(N=256\) symbols, as a block size (we obtained similar results for other values of \(N>>1\)). Moreover, the QPSK modulation was adopted. In some scenarios, LDPC codes are utilised in the Monte Carlo simulations. When LDPC codes are used, these have a code rate of \(\%\). The length of the LPDC codes utilized in the simulations is 32,400 from the DVB-S.2 standard (also used in [10]). LDPC codes have gained significant attention due to their excellent performance in various communication systems, including wireless, satellite, and optical communication. These are characterized by their sparse parity-check matrices, which lead to efficient encoding and decoding algorithms. Regular LDPC codes were employed in the simulations, with all variable nodes and all check nodes having the same degree. In the simulations, we employed a min-sum belief propagation decoder with 20 iterations, using hard decision. Figure 3 shows a 3D user distribution map that allows for the viewing of the distribution of users and also the distribution of the panels, and which gives an idea of how much each user is aligned with each panel. Figure 3 also shows the scenario considered in the simulations, with four panels on the ceiling, each with a different number of antennas. Moreover, the number of users varies, depending on the scenario. Note that their locations are randomly selected by the simulation, i.e., each run of the Monte Carlo simulation considers a different location for the users. Different graphics include results for \"full LIS\" and \"partial LIS\". \"Full-LIS\" corresponds with the performance results of the regular LIS with all panels and all antennas in each panel. On the other hand, \"partial LIS\" means that such results with this designation correspond with the use of a subset of the total number of antennas that compose the LIS system. \"Partial LIS\" considers the antennas that are closer to each user while mitigating the level of interference of the other users. In other words, \"full LIS\" considers the total number of panels, and total number of antennas. In our simulations, we considered four panels. \"Partial LIS--one panel\" corresponds with the use of only one panel (the closest  
Figure 3: Scenario considered in the simulations with four panels. panel) of the four total panels. In the other scenarios of \"partial LIS\" that do not correspond with the use of one panel, the number of antennas under consideration is stated. For example, in the configuration 4 \(\times\) 400, \"full LIS\" corresponds with 4 panels of 400 antennas on each panel, while \"partial LIS--one panel\" corresponds with the use of a single panel, i.e., 1 \(\times\) 400. Moreover, \"partial LIS--225 antennas\" corresponds with the use of only 225 of the 4 \(\times\) 400 = 1600 antennas of the full LIS.