Cross-Layer Protocols for WSNs

Fahmy, Hossam Mahmoud Ahmad

Most of the proposed communication protocols exploiting the collaborative nature of WSNs and its correlation characteristics improve energy efficiency. However, they follow the traditional layered protocol architectures; specifically, the majority of these communication protocols are individually developed for different networking layers, i.e., transport, network, medium access control (MAC), and physical layers. While they may realize high performance in terms of the metrics related to each of these individual layers, they are not jointly optimized to maximize the overall network performance while minimizing the energy expenditure. Considering the scarce energy and processing resources of WSNs, joint optimization, and design of networking layers, i.e., cross-layer design, stands as the most promising alternative to inefficient traditional layered protocol architectures. The basic principle of cross-layer design is to make information available to all levels of the protocol stack. It allows the definition of protocols or mechanisms that do not meet the isolation layers of the OSI model (van der Schaar M, Shankar NS, Wirels Commun 12(4):50–58, 2005; Srivastava V, Motani M, Commun Mag 43(12):112–119, 2005). In fact, cross-layer integration and design techniques result in significant improvement in terms of energy conservation in WSNs (van Hoesel L, Nieberg T, Wu J, Havinga PJM, Wirel Commun 11(6):78–86, 2004; Yetgin H, Cheung KTK, El-Hajjar M, Hanzo L, Trans Veh Technol 64(8):3795–3803, 2015). Several researches started by focusing on the cross-layer interaction and design to develop new communication protocols (Melodia T, Vuran MC, Pompili D, The state of the art in cross-layer design for wireless sensor networks. Vol 3883, in Lecture Notes in Computer Science-Wireless Systems and Network Architectures in Next Generation Internet (EuroNGI), by M Cesana and L Fratta, Berlin/Heidelberg: Springer, pp 78–92, 2005). Yet, these works either provide analytical results without communication protocol design or perform pairwise cross-layer design within limited scope, e.g., only MAC and network layers, which do not consider all of the networking layers involved in WSNs communication, such as transport, network, MAC, and physical layers. Considering the scarce energy and processing resources of WSNs, joint optimization, and design of networking layers, i.e., cross-layer design, stands as the most promising alternative to inefficient traditional layered protocol architectures. There are considerable benefits of rethinking the protocol functions of networking layers in a unified way so as to provide a single communication module for efficient communication in WSNs.