# On the Performance of Partial LIS for 6G Systems
## 3 Simulation Results and Analysis
It is worth noting that, in the case of the \"full LIS\", the performance obtained with the MRC receiver is almost superimposed over those obtained with the ZF/MMSE receivers, while in the case of the \"partial LIS--one panel\" the MRC shows a small degradation compared with the ZF/MMSE. Figure 4: Performance results of the 4 \(\times\) 400 LIS system, with 2 users, without LDPC codes, and with and without the partial LIS. Figure 5: Performance results of the 4 \(\times\) 225 LIS system, with 2 users, without LDPC codes, and with and without the partial LIS. In the previous graphics, one can see that \"partial LIS--one panel\" achieves the best performance results, for both 4 \(\times\) 400 LIS and 4 \(\times\) 225 LIS. Figure 6 shows the results with a partial LIS, using a single panel, with 2 users, without LDPC codes, but while performing a comparison between different LIS configurations. As can be seen from Figure 6, the use of one panel with the configuration 4 \(\times\) 400 LIS (i.e., with each panel corresponding to 1 \(\times\) 400 LIS) slightly outperforms the configuration 4 \(\times\) 225 LIS--one panel (i.e., 1 \(\times\) 225), for all receiver types. Nevertheless, the results obtained with 4 \(\times\) 50 LIS--one panel (i.e., 1 \(\times\) 50) experience a significant degradation as compared with the other two LIS configurations, while the MRC and EGC receivers perform very badly. This occurs because the diversity gain obtained with the 50 antennas is very low. Figure 7 shows the performance results of the 4 \(\times\) 400 LIS system, with 16 users, without LDPC codes, with and without the partial LIS. Similar to the results shown in Figure 4 (2 users), Figure 7 shows that, with 16 users and for this LIS configuration, the utilization of a single panel leads to a gain in performance as compared with the scenario of the full LIS configuration. Moreover, such gain is higher in the case of 16 users (Figure 7) than in the case of 2 users (Figure 4). This occurs because the use of one panel allows interference mitigation (as compared with the full LIS), whose effect is more visible for a higher number of interfering users. Figure 8 shows the performance results of the 4 \(\times\) 361 LIS system, with several number of users (2, 8 and 16 users), with the partial LIS, and without LDPC codes. As expected, the performance degrades with the increase in the number of users. Nevertheless, as previously shown, the performance degradation is partially mitigated using the partial LIS. Moreover, the performance degradation with the increase in the number of users is very low in the case of the ZF/MMSE receivers, which is achieved at the cost of a higher processing power, as compared with the MRC/EGC receivers. Figure 6: Performance results of several LIS configurations, with 2 users, without LDPC codes, with the partial LIS—one panel. Figure 8: Performance results of the 4 \(\times\) 361 LIS system, with several number of users, with the partial LIS, and without LDPC codes. Figure 7: Performance results of the 4 \(\times\) 400 LIS system, with 16 users, without LDPC codes, with and without the partial LIS. Figure 9 aims to perform a comparison between the results with and without LDPC codes. Note that the use of LDPC with the full LIS has been previously analysed in [10]. Figure 9 shows results like those of Figure 5 but in which the LDPC codes are also shown, considering the scenario with the partial LIS. One can see that the use of LDPC codes allows for a performance improvement for all receiver types, and with the partial LIS. Note that the partial LIS corresponds with the use of one panel. The gain achieved with the LDPC codes is of the order of 2 dB in the different scenarios.