Typical and atypical hierarchical routing protocols for WSNs : A review

Wireless Sensor Networks (WSNs) have emerged as the most preferable network for many applications which require pervasive computing. All such applications and environments need energy efficient routing. This has led to the evolution of hierarchical routing which has attracted many professionals towards this field for research and development. Hierarchical routing is energy-efficient and useful in several situations. It can be basically categorized in two types. First one is typical hierarchical routing protocols and second one is atypical hierarchical routing protocols. However, there are no such significant differences between both of them because atypical protocols are just a subset of typical hierarchical routing protocols. There are various survey papers which focus on typical routing protocols and very few papers which cover especially atypical routing protocols. There is no such paper which covers both categories collectively which can ease users to compare them for the best suitability. This survey aims to fulfill the same requirement and covers some renowned protocols from both categories.