# Energy and Spectral Efficiency Balancing Algorithm for Energy Saving in LTE Downlinks
## 4 Performance Evaluation of the Proposed SET algorithm
### Impact of Varying Traffic Loads in Congested Network
#### 4.3.1 Impact of Varying Network Loads on a Congested Network Using an Omni-Directional Antenna  
An omni-directional antenna that spreads radio signals in all directions has been used in a congested network scenario that contains a large number of UE \(>\) 100 [30]. The pieces of UE are uniformly distributed with an inter-eNodeB distance of 500 m. The objective of implementing this scenario is to determine the network performance under an increasingly stressful condition, where Figures 12-15 present the results of the SE, delay, energy consumption, and SET, respectively.  
A comparison of the SE between the proposed SET algorithm and the DRX power-saving algorithm has been shown in Figure 12. As explained in Section 3, the proposed SET algorithm allocates the RBs to users with good channel states, which exhibits better performance than the DRX algorithm. It worth noting that disregarding the selection of an appropriate channel state by the DRX algorithm results in poor SE, which affects the performance of the eNodeB.  
A comparison between the delay of the proposed SET algorithm to that of the DRX power-saving algorithm has been presented in Figure 13. The DRX algorithm exhibits an increased delay because the RBs allocation is established while disregarding the packet delay requirements. Moreover, the proposed algorithm is able to minimize the delay because it uses an appropriate selection of window size. Given the frequent arrival of users and the spread of radio signals in different directions by the omni-directional antenna, the competition among users to access the radio signals increases the delay in the case of the DRX algorithm that, consequently, increases the interference level.  
Subsequently, the energy consumption of the eNodeB is investigated, where Figure 14 shows that increasing the number of UE in the network environment will cause a rise in the interference, thereby increasing the energy consumption, in which the increase of interference makes it difficult to find an optimal power transmission. For this reason, the proposed algorithm outperforms the DRX power-saving algorithm with the least energy consumption due to its ability to adjust eNodeB by predicting the arrival pattern of user requests.  
Figure 12: SE as the number of UEs are increased in congested network for with omni-directional antenna.  
The impact of increasing the number of UE pieces in a congested network using omni-directional antenna by utilizing SET has been presented in Figure 15, in which the increase in the SE will always increase the EE.  
The proposed SET algorithm achieves the optimal point at 2.2 bit/s/Hz, which is higher than that of the DRX power-saving algorithm whose optimal point was at 1.78 bit/s/Hz. This result indicates that the proposed SET algorithm outperforms the DRX algorithm because it can achieve optimal value with reduced energy consumption.  
Figure 14: Energy consumption by increasing number of UEs in congested network for with omni-directional antenna.  
Figure 13: Delay as the number of UEs are increased in congested network for with omni-directional antenna.