## 4 Performance Evaluation
### Simulation Results
#### 4.2.1 Received Data Rate  
Figure 3 shows the average received data rate with different number of users (i.e., U = 1, 10, 20, 30,..., 100 users), where a data packet with 4000 bytes is transmitted by the selected TP for each serving user. Note that \"FR1 within FR1\", \"FR2 within FR2\", and \"Sub-THz (FR3) within Sub-THz\" denote the connection (i.e., TP) is selected in FR1, FR2, and FR3 may change within the initially selected FR1, FR2, and FR3, respectively. These are equivalent to max-SINR rule-based TPS with single connectivity in single-band wireless networks, e.g., [8,12]. \"any FR among (FR1, FR2, FR3)\" also denotes that the connection can be changed within FR as well as across FR (e.g., from FR1 to FR3), which is equivalent to  
\begin{table}
\begin{tabular}{c c} \hline \hline
**System Parameter** & **Values** \\ \hline Channel model & UMi-Street Canyon \\ \hline Carrier frequency (FR1, FR2, FR3) & (4, 28, 32) GHz \\ \hline Bandwidth (FR1, FR2, FR3) & (20, 200, 3200) MHz \\ \hline TP transmit power (FR1, FR2, FR3) & (44, 44, 44) dBm \\ \hline Number of TPs (FR1, FR2, FR3) & (4, 16, 32) TPs at 3 m height, see Figure 2 \\ \hline User distribution & 100\% randomly deployed at 1.5 m height \\ \hline Traffic model & FTP Model 3 \\ \hline Network Layout & 270 m \(\times\) 50 m \\ \hline Simulation time & 10,000 slots \\ \hline \hline \end{tabular}
\end{table}
Table 1: Key system parameters of the simulation.  
Figure 2: An example of deployment with TPs (X: TP operating in FR1; O: TP operating in FR2; and \(\square\): TP operating in FR3) in UMi-Street Canyon environment, where 4 TPs operating in FR1, 6 TPs operating in FR2, and 8 TPs operating in FR3 are assumed to be deployed at 3m height.  
TPS with single connectivity in multi-band wireless networks, e.g., [5]. Here, Figure 3a-c show the average received data rate in the case of allowing only a single connection for a user, in the case of allowing two connections for a user, and in the case of allowing three connections for a user, respectively. (i) The result in Figure 3a shows that the average data rate of users served by TP operating in FR3 is higher than the others. This is due to the fact that we allocate the wider system bandwidth to FR3, compared to that in FR1 and FR2. Also, only TP within the FR, which is selected initially, can be selected and changed. Interestingly the average data rate of users served by any FR is not the highest. This is because the TP operating in FR3 is not often selected to serve users. It also implies that the channel gain in FR3 is lower than that in FR1 and FR2. (ii) In contrast to the case of allowing only single connection, the average data rate of users by selecting TP operating any FR having the highest SINR is higher than the others in case of allowing multiple connections for users as shown in Figure 3b,c. We infer that multi-connection operation across multiple bands is beneficial for the system performance in terms of received data rate for users, compared to the multi-connection operation with a single band. (iii) In addition, as the number of connections increases, the average received data rate also increases. We also infer that multiple connections and increasing the number of connections for a user lead to the better data rate.