# Energy Saving in Wireless Sensor Networks via LEACH-Based, Energy-Efficient Routing Protocols
## 6 Conclusions  
This research article focused on hierarchical, energy-efficient routing protocols for WSNs and particularly LEACH, which is a pioneering protocol of this type, along with some of its numerous descendants. Specifically, an overview of typical examples of these protocols was provided, while their main advantages and disadvantages were indicated. From the study conducted, it was made evident that LEACH descendants have proven to enhance the operation of their ancestor regarding energy efficiency. Nevertheless, such protocols differentiate too in terms of many other metrics, such as scalability, throughput, cluster formation, complexity, load balance, processing and communication overhead, latency, communication model, location information, modulation techniques, fault tolerance, and channel encoding. For these reasons, it is apparent that the aptness of each hierarchical protocol for energy-efficient routing in WSNs is application-dependent.  
Additionally, a novel protocol of this type named T-LEACH\({}_{\text{SAS}}\) was proposed. The specific protocol combines the threshold-based approach for selecting cluster heads that was first introduced in T-LEACH, which is a well-known protocol, along with a mechanism for sleep-awake scheduling, which ensures that nodes transition between active and sleep modes judiciously and, thus, conserve energy during periods of inactivity. The results of the simulation tests executed in all scenarios examined evinced that T-LEACH\({}_{\text{SAS}}\) enhances the beneficial outcomes of T-LEACH and, consequently, constitutes a promising choice for energy-efficient routing in WSNs, because it effectively reduces energy wastage on unnecessary data transmissions and inefficient clustering. On the other hand, sleep-awake scheduling is inevitably associated with the intermittent operation of the network, which may be inappropriate for a certain number of applications.  
The authors of this article intend to extend their future research, so that it will incorporate energy efficiency along with other metrics in order to achieve the multiobjective optimization of WSNs' performance.  
Figure 13: Influence of the number of nodes on the round when first node dies (FND) and last node dies (LND) for LEACH, T-LEACH, and T-LEACH\({}_{\text{SAS}}\).  
**Author Contributions:** Conceptualization, D.K., D.R. and G.S.; methodology, D.K., D.R. and G.S.; software, D.R. and G.S.; validation, D.K., D.R. and G.S.; formal analysis, D.K., D.R. and G.S.; resources, D.K., D.R. and G.S.; writing--original draft preparation, D.K., D.R. and G.S.; writing--review and editing, D.K., D.R. and G.S.; visualization, D.K., D.R. and G.S.; supervision, D.K.; project administration, D.K., D.R. and G.S. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research received no external funding.  
**Data Availability Statement:** The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author.  
**Conflicts of Interest:** The authors declare no conflict of interest.