## 2 Related Work
A survey of state-of-the-art routing techniques for WSNs was presented in [40], whose authors outlined the clustering architecture in WSNs and presented a simple classification based on only three attributes, _i.e._, parameters used for CH election, whether there exist a centralized control during clustering, and hops between nodes and CH in intra-cluster communication. Furthermore, the survey highlighted the challenges in clustering WSNs and briefly introduced a few clustering routing techniques. [PERSON] _et al_. [41] have made a simple survey of clustering routing protocols, including only six typical clustering algorithms. The authors of the survey simply compared these clustering routing algorithms based on some performance parameters, including energy conservation, network lifetime, data aggregation, robustness, scalability, security, and _etc_. Another simple survey on clustering routing algorithms was given by [PERSON] [42]. Only eight popular clustering routing protocols are covered in this survey, such as LEACH, PEGASIS, TEEN, APTEEN, _etc_. The authors of the survey briefly compared these clustering routing approached based on energy conservation and the network lifetime. An overview of [PERSON] and [PERSON] [43] focuses on design challenges and comparative analysis of WSN clustering routing algorithms for improving the network lifetime. The authors of the overview analyzed many challenging factors that influenced design of routing protocols in WSNs, and presented a simple classification of routing protocols. Besides, many efficient clustering based classical WSN routing protocols with comparative analysis were discussed in the overview. Finally, we summarize the previous work related to ours in Table 1, which highlights the main contributions of each author along with the year of the survey. However, our work differs from the others due to a few distinctive characteristics, which are described in last section. \begin{table}
\begin{tabular}{|c|c|c|c|} \hline
**Year** & **Authors** & **Literature** & **Main contributions** \\ \hline
2006 & [PERSON]. _et al_. & Comparison of clustering algorithms and protocols for wireless sensor networks [33] & \(\backslash\)1 Discussion of basic concepts related to the clustering process \\ \hline
2007 & [PERSON] _et al_. & A survey on clustering algorithms for wireless sensor networks [32] & \(\backslash\)2 Analysis of LEACH-based protocols \\ \hline
2008 & [PERSON] _et al_. & Algorithms for node clustering in wireless sensor networks: a survey [34] & \(\backslash\)1 Presentation of a classification based on cluster-formation parameters and CH election criteria \\ \hline
2008 & [PERSON] _et al_. & Algorithms for wireless sensor networks: a survey [35] & \(\backslash\)2 Discussion of the key design challenges of WSN clustering \\ \hline
2008 & [PERSON] _et al_. & Cluster head selection in clustering algorithms for wireless sensor networks: a survey [35] & \(\backslash\)1 Discussion of CH selection strategies based on the classification of deterministic scheme, adaptive scheme and combined metric scheme \\ \hline
2009 & [PERSON] _et al_. & Towards clustering algorithms in wireless sensor networks-a survey [36] & \(\backslash\)1 Presentation of a classification of WSN clustering schemes based on 8 clustering attributes \\ \hline \end{tabular}
\end{table} 
Table 1: Summary of Previous Surveys on Clustering Routing Protocols in WSNs