# Energy Saving in Wireless Sensor Networks via LEACH-Based, Energy-Efficient Routing Protocols
## 5 Comparative Performance Evaluation
### Presentation and Evaluation of Simulation Tests
It was found that T-LEACH\({}_{\text{SAS}}\), considering the depletion of the last living node, achieves an extension of network lifetime by 659% when compared to LEACH and by 51.2% when compared to T-LEACH. Figure 7 illustrates the number of the network nodes that remain alive per simulation round. Figure 5: Nodes alive per round in the second scenario for LEACH, T-LEACH, and T-LEACH\({}_{\text{SAS}}\). Figure 6: Total data bits transmitted to the base station per round in the second scenario for LEACH, T-LEACH, and T-LEACH\({}_{\text{SAS}}\). Also, it was found that the total volume of data transmitted to the base station by using T-LEACH\({}_{\text{SAS}}\) increased by 247% and 15% when compared to that achieved when using LEACH and T-LEACH, respectively. Figure 8 depicts the total volume of data transmitted per simulation round in the third simulation scenario. Based on the first three scenarios investigated, it becomes obvious that both in sparse and dense network topologies, T-LEACH\({}_{\text{SAS}}\) compared to LEACH and T-LEACH provides considerably longer lifetime of network nodes. Consequently, thanks to their extended lifespan network, nodes transmit a greater volume of data to the base station, as confirmed by the simulation results. Next, in the fourth scenario studied, it was supposed that the WSN under consideration comprises of a base station located at position (0, 0) along with 100 nodes. It was found that T-LEACH\({}_{\text{SAS}}\), considering the depletion of the last living node, achieves an extension of network lifetime by 174% when compared to LEACH and by 15.2% when compared to T-LEACH. Figure 9 graphically demonstrates the number of the network nodes that remain alive per simulation round. Figure 8: Total data bits transmitted to the base station per round in the third scenario for LEACH, T-LEACH, and T-LEACH\({}_{\text{SAS}}\). Figure 7: Nodes alive per round in the third scenario for LEACH, T-LEACH, and T-LEACH\({}_{\text{SAS}}\). Furthermore, it was found that the total volume of data transmitted to the base station by using T-LEACH\({}_{\text{SAS}}\) increased by 102% and 14% when compared to that achieved when using LEACH and T-LEACH, respectively. Figure 10 depicts the total volume of data transmitted per simulation round in the fourth simulation scenario. Finally, in the fifth scenario studied, it was supposed that the WSN under consideration comprises of a base station located at position (100, 220) along with 100 nodes. It was found that T-LEACH\({}_{\text{SAS}}\), considering the depletion of last living node, achieves an extension of network lifetime by 136% when compared to LEACH and by 12% when compared to T-LEACH. Figure 11 graphically demonstrates the number of the network nodes that remain alive per simulation round. Moreover, it was found that the total volume of data transmitted to the base station by using T-LEACH\({}_{\text{SAS}}\) increased by 107% and 17.1% when compared to that achieved when using LEACH and T-LEACH, respectively. Figure 12 depicts the total volume of data transmitted per simulation round in the fifth simulation scenario. Figure 10: Total data bits transmitted to the base station per simulation round in the fourth scenario. Figure 9: Nodes alive per round in the fourth scenario for LEACH, T-LEACH, and T-LEACH\({}_{\text{SAS}}\). The study of the first scenario in common with the fourth scenario and the fifth scenario makes it clear that the closer to the center of the field of interest the base station is located, the higher energy efficiency and greater data transfer are achieved. Actually, the base station is situated at the edge of the network field in the fourth scenario and out of the bounds of the network field in the fifth scenario. Thus, the average distance of the sensor nodes to the base station is accordingly increased in these last two scenarios examined.