Mitigating packet dropping problem in mobile ad hoc networks: Proposals and challenges

In mobile ad hoc networks (MANETs), nodes usually cooperate and forward each other's packets in order to enable out of range communication. However, in hostile environments, some nodes may deny to do so, either for saving their own resources or for intentionally disrupting regular communications. This type of misbehavior is generally referred to as packet dropping attack or black hole attack, which is considered as one of the most destructive attacks that leads to the network collapse. The special network characteristics, such as limited battery power and mobility, make the prevention techniques based on cryptographic primitives ineffective to cope with such attack. Rather, a more proactive alternative is required to ensure the safety of the forwarding function by staving off malicious nodes from being involved in routing paths. Once such scheme fails, some economic-based approaches can be adopted to alleviate the attack consequences by motivating the nodes cooperation. As a backup, detection and reaction schemes remain as the final defense line to identify the misbehaving nodes and punish them. In this paper, we make a comprehensive survey investigation on the state-of-the-art countermeasures to deal with the packet dropping attack. Furthermore, we examine the challenges that remain to be tackled by researchers for constructing an in-depth defense against such a sophisticated attack. © 2011 IEEE

Bio-inspired Medium Access Control for Wireless Sensor Networks

This thesis studies the applications of biologically inspired algorithms and behaviours to the Medium Access Control (MAC) layer of Wireless Sensor Networks (WSNs). By exploring the similarity between a general communications channel and control engineering theory, we propose a simple method to control transmissions that we refer to as transmission delay. We use this concept and create a protocol inspired by Particle Swarm Optimisation (PSO) to optimise the communications. The lessons learned from this protocol inspires us to move closer to behaviours found in nature and the Emergence MAC (E-MAC) protocol is presented. The E-MAC protocol shows emergent behaviours arising from simple interactions and provides great throughput, low end-to-end delay and high fairness. Enhancements to this protocol are later proposed. We empirically evaluate these protocols and provide relevant parameter sweeps to show their performance. We also provide a theoretical approach to proving the settling properties of E-MAC. The presented protocols and methods provide a different approach towards MAC in WSNs