# Multi-Connectivity for Multicast Video Streaming in Cellular Networks
## 7 Simulations  
We studied the performance of the proposed MC multicast in an MBMS system consisting of seven urban macro cells [41]. A base station was located at the center of each cell, and UEs were distributed uniformly at random in the cells. To create 5G-specific physical layer conditions, we created channels using the models recommended by 3 GPP [42]. The SNR used to rate mappings was also measured according to 3 GPP specifications [42]. Other relevant simulation parameters are given in Table 2. The cell-edge users in the system were multi-connected to all the base stations in the system. In all the cells, one PRB was allocated to the multicast stream in each time slot. Multi-connected users successfully received a packet if they could decode the content from at least one of the base stations. Other users only received the multicast content from their primary base stations. The number of packets delivered successfully and the number of UEs successfully served were used as the performance metrics in these simulations. In Figure 3, we plot the average number of packets successfully received by UEs under the CGA and the DGA resource allocation algorithms. One packet was transmitted in every sub-frame (1 ms), and we plotted the average number of packets successfully received by all the UEs in the system over a period of 10 s (10,000 packets). As expected from the discussions in Section 6, we observe that the centralized policy performs better than the distributed policy. However, despite its distributed nature, the packet loss under the DGA algorithm is at most 0.3% \begin{table}
\begin{tabular}{l l} \hline \hline
**Parameters** & **Values** \\ \hline System bandwidth & 20 MHz \\ Cell radius & 250 m \\ Path loss model & L = 128.1 + 37.6 \(\log 10(d)\), with \(d\) in kilometers \\ Lognormal shadowing & Log normal fading with 10 dB standard deviation \\ White noise power density & \(-\)174 dBm/Hz \\ Noise figure & 5 dB \\ Transmit power & 46 dBm \\ \hline \hline \end{tabular}
\end{table} 
Table 2: System simulation parameters [42]. greater than that under the CGA algorithm. Therefore, in the absence of centralized control, the DGA algorithm can provide a performance close to that of the centralized policy. In Figures 4-6, we compare the performance of MC multicasting with that of the conventional Single-Connectivity (SC) multicast transmission scheme. For resource allocation in SC multicasting, we used the DGA algorithm from Section 6, and the CGA algorithm was used in the resource allocation for MC multicasting. Note that since users are connected to a single base station in SC multicasting, the DGA algorithm provides the optimal solution for maximizing the number of users served. For the plots in Figures 4 and 5, data were transmitted at a fixed rate in each sub-frame. The points in these plots were obtained by averaging over 10,000 sub-frames. Figure 3(a) illustrates the number of packets successfully delivered under MC and SC multicasting as the number of users increased. We observe a decline in the number of packets successfully delivered as the number of UEs increases. However, the number of packets successfully delivered under MC multicasting is much larger than that under SC multicasting. Figure 3(b) plots the same metric as a function of the cell radius. We observe that the number of packets successfully delivered decreases as the cell sizes increase. This is because the path loss of the cell edge users increases as the cells become larger. The key observation here is that the performance gap between MC and SC follows an increasing trend. The relative performances of MC and SC are similar to what we observe in Figure 3(a). Figure 4: Comparisons of the average number of packets (out of 10,000) successfully delivered under SC and MC multicasting. Resource allocation was performed using the proposed CGA algorithm (Algorithm 3), and the results are plotted as a function of (**a**) an increasing number of users and (**b**) increasing cell radii.