## 5 Simulation Results
### Network System Performance  
This section compares the proposed SSC-UA scheme with: (1) The joint optimization of SBS off and user association (BS-off-UA) algorithm, where the SBS states in BS-off-UA are Off and Sleep. (2) The optimization of user association without considering the SBS off (BS-on-UA) algorithm. Figure 10 compares the power consumption and average delay of the SBSs for each scenario with different \(\alpha\). The average delay of the SBSs during the time period is calculated by the following equation. \[\overline{D}^{i}\left(\mathbf{\rho}^{t}\right)=\frac{1}{n}\sum_{i\in B_{m}^{t}}d_{ i,s}^{t}\left(\rho_{i}^{t}\right)+d_{i,w}^{t}\left(\rho_{i}^{t}\right) \tag{36}\]  
where \(n\) denotes the number of SBSs in the On state in period \(t\). From Figure 10, it can be observed that as the value of \(\alpha\) increases, the energy consumption of all three schemes \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**BS Number**} & \multicolumn{2}{c}{**RMSE**} & \multicolumn{2}{c}{**MAE**} \\ \cline{2-5}  & **LSTM** & **ARIMA** & **LSTM** & **ARIMA** \\ \hline Cell\_000111 & 135.48 & 410.9 & 113.45 & 354.88 \\ Cell\_000113 & 61.81 & 474.92 & 54.79 & 65.72 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Comparing the prediction effect of two models. Figure 8: Traffic prediction error of base station Cell_000111. Figure 9: Traffic prediction error of base station Cell_000113. decreases and the delay increases. This is because the larger \(\alpha\) indicates that the proportion of energy consumption in the objective function increases, and the objective function optimization is more sensitive to energy consumption. The final result is to reduce energy consumption by increasing the delay, so as to reduce the value of the overall objective function. Comparing the SSC-UA and BS-off-UA schemes, we can find that the delay of the SSC-UA scheme is always lower than that of the BS-off-UA scheme, but the energy consumption is slightly higher than that of the BS-off-UA scheme. The reason for this result is that there is a Standby state for the SSC-UA scheme, and the energy consumption of these SBSs is larger than that of the Sleep state SBSs. On the other hand, the Standby state SBSs can be woken up faster than the Sleep state SBSs, and the system wake-up delay is much lower than that of the Sleep state SBSs, so the delay is reduced. Although the SSC-UA scheme reduces the latency at the expense of energy consumption, the algorithm complexity of the SSC-UA scheme is much lower than that of the BS-off-UA scheme. This is mainly due to the fact that in the SSC-UA scheme we predict the traffic of the SBSs through the LSTM network and make the initial decision on the state of the SBSs, which greatly reduces the number of SBSs to be considered in the heuristic algorithm. The BS-off-UA scheme needs to take all of the SBSs into account, and the algorithm complexity is much higher than that of the SSC-UA scheme. In addition, because all the SBSs are on in the BS-on-UA scheme, their energy consumption is kept at a high level, and there is no wake-up delay in the system, and the load of each SBS is in a more balanced state, so the overall system delay is low. Figure 11 compares the cumulative distribution function (CDF) of the delay of the SSC-UA scheme and the BS-on-UA scheme. Compared with the BS-on-UA scheme, the CDF of the delay of the SSC-UA scheme is on the left, which indicates that the network delay of the SSC-UA scheme is smaller than that of the BS-on-UA scheme in general. Figure 10: Comparison of average latency and total energy consumption of the three schemes. Figures 12 and 13 show the continuous 48-h network conditions of the SSC-UA and BS-on-UA schemes, including the traffic demand, the number of SBSs to be turned on, and the average delay and the energy consumption of the network for each hour, where the left vertical coordinate indicates the number of SBSs, and the right vertical coordinate indicates the normalized traffic demand, average delay and energy consumption.