# A Novel Power-Saving Transmission Scheme for Multiple-Component-Carrier Cellular Systems
## 5 Results and Discussion
From Figure 7, meanwhile, the following fact, which was likewise illustrated above with Figure 5, can clearly be seen: due to the water-filling approach, the maximum available transmission power was almost fully utilized for any given configuration of CCs under both schemes. Accordingly, the channel efficiency enhanced. The latter point is illustrated in Figure 8, which shows the fairness indexes for both the RT and NRT users over time. It was also found, as shown in Figure 8, that for a specific number of users of the cell, the fairness indexes for the different types of users were nearly convergent, consistently reaching a level of less than 2% difference from the target. Moreover, even when the arrival rate of new users increased significantly,  
Figure 6: A comparison of the levels of basic power consumption for the proposed scheme and the conventional scheme. Figure 7: A comparison of the levels of transmission power consumption for the proposed scheme and the conventional scheme. the fairness indexes for both the RT and NRT users were nearly maintained at their respective target levels following no more than a few minutes of scheduling rounds (iterations) (the variable results for each round of the 5-min intervals shown in Figure 8, where the intervals were based on the traffic pattern indicated in Figure 3, are unrelated to any of the optimization variables for the power minimization problem being considered. Accordingly, these results do not reflect the stability of the proposed scheme in any way). Relatedly, while the fairness indexes for both types of users were instantly degraded whenever the traffic load was significantly increased, they were still maintained at levels above 0.7 during almost all those brief periods of degradation. For the sake of completeness, Table 1 lists the average levels of total power consumption, under the proposed scheme and the conventional scheme, for different minimum required data rates for the NRT users and RT users given the traffic pattern indicated in \[\varphi(h_{\text{d}})=3.2\log_{10}(11.75h_{\text{d}})^{2}-4.97 \tag{15}\]0 As indicated by Table 1, the proposed scheme outperforms the conventional scheme in terms of power-saving effectiveness for various minimum required data rates for the NRT users and RT users. This better performance results from the proposed scheme having the substantial advantage of flexibility in terms of activating/deactivating the SCCs according to dynamically fluctuating traffic loads, thus allowing unnecessary power consumption to be avoided. In addition, when the minimum required data rates are set relatively low (_i.e._, \(r_{\text{req},k}=300\) kbps for \(k\in\Re^{(1)}\) and \(r_{\text{req},k}=500\) bps for \(k\in\Re^{(2)}\)), the resulting power-saving ability is particularly significant (with consumption lowered by 50.26%). This is due to the fact that, under a given a traffic pattern, and as indicated by Equation (1), when the minimum required data rate for each user is higher, the accumulated transmission power will also be larger, which, in the event that the accumulated transmission power exceeds the maximum transmission power of the currently active CC(s), will lead to the activation of more SCC(s) to aid in the transmissions. As a result, more power will be consumed. Meanwhile, when the minimum required data rates are set lower, the resulting power consumption is also lower. For the conventional scheme, on the other hand, because the two SCCs were continuously active regardless of the lightness or heaviness of the traffic load, the level of total power consumption remained close to 60 W almost continuously.