# A Novel Power-Saving Transmission Scheme for Multiple-Component-Carrier Cellular Systems
## 5 Results and Discussion
Moreover, \(\Phi_{\text{target}}^{(m)}\), \(m=1\), 2, were both set at 1; \(\eta^{(m)}\), \(m=1\), 2, were both set at 0.1; \(h_{\text{b}}=100\) m; \(h_{\text{d}}=1\) m; the threshold \(y_{\text{th}}\) in the SAD component was set at 10; and the simulation time was set to 1 h.  
For demonstrations, the number of users was the variable, with the probability of a given user being an RT user set at 30%, meaning that the probability of a given user being an NRT user was set at 70%. The considered variation in the number of users over time is shown in Figure 3. In that figure, an increase in users from one time point to the next indicates the addition of new users, while a decrease indicates users leaving the cell. Accordingly, the numbers of RT and NRT user sessions being transmitted versus time in the 3-CC cellular system are respectively shown in Figure 4. As shown in Figures 3 and 4 during the interval from 35 to 40 min, there is a gap between the total number of users in the cell and the total number of sessions being transmitted. This gap is mainly due to the system capacity limit, such that some users' requests are forced, by the check of SAC, to be buffered in their respective processing queues to avoid causing service quality degradation of other user sessions that are currently being served. Given the conditions specified above, Figure 5 presents a comparison of the total power consumption levels of the proposed scheme and the conventional scheme. As shown, the proposed scheme resulted in significantly reduced total power consumption at the BS transceivers during periods of relatively light traffic. This effect was achieved because under the proposed scheme, some SCCs were dynamically deactivated when the traffic load decreased. As such, unnecessary power consumption was significantly reduced even as the respective minimum requirements of all the user sessions were satisfied and the fairness indexes for the different types of users were still efficiently controlled at acceptable levels. Figure 3: The number of users of the cell over time. Next, as can be seen in Figures 3 and 5 under the proposed scheme, for any periods in which the total number of users was equal to or less than 20, the power consumed by the BS transceivers was consistently reduced to a relatively low level (_i.e._, around 20 W). In contrast, under the baseline scheme, the power consumed by the BS transceivers remained at a much higher level (_i.e._, around 60 W) for almost the entire simulation. This was due to the fact that, for a given configuration of CCs, if the water-filling approach based on Equation (13) was applied, the maximum available transmission power was completely utilized for distribution over each sub-channel. Next, in order to more clearly illustrate the behavior of the two schemes with regard to traffic load, we introduce two graphs (Figures 6 and 7) in which the results for the basic levels of power consumed and for the levels of transmission power consumed over time, respectively, are plotted. By referencing Figures 3 and 6 it can be seen that, under the proposed scheme, the first SCC (CC-2) becomes activated when the number of users is increased to 25, while the second SCC (CC-3) is subsequently activated  
Figure 4: The numbers of RT and NRT user sessions over time. Figure 5: A comparison of the levels of total power consumption for the proposed scheme and the conventional scheme. when the number of users reaches 45. In contrast, when the number of users is relatively low, both of the SCCs are deactivated. These results imply, then, that the proposed scheme can, in comparison to the other scheme, effectively activate/deactivate the SCCs according to uncertain variations in traffic loads over time in order to lessen or prevent unnecessary energy consumption.