An Energy-Efficient Cross-Layer Routing Approach for Wireless Sensor Networks Using Distributed Beamforming

Wireless sensor networks are valuable assets to both the commercial and military communities with applications ranging from industrial control on a factory floor to reconnaissance of a hostile border. In most applications, the sensors act as data sources and forward information generated by event triggers to a central sink or base station (BS). The unique role of the BS makes it a natural target for an adversary that desires to achieve the most impactful attack possible against a WSN with the least amount of effort. Even if a WSN employs conventional security mechanisms such as encryption and authentication, an adversary may apply traffic analysis techniques to identify the BS. This motivates a significant need for improved BS anonymity to protect the identity, role, and location of the BS. Previous work has shown distributed beamforming to be an effective technique to boost BS anonymity in WSNs; however, the energy consumption of these networks depends on helper relay availability and the energy required to recruit relays. In this paper we propose a novel, cross-layer link cost that balances the relay recruitment energy and the number of recruited relays. By incorporating available helper relays directly into the routing link cost, we select routes that maximize the use of distributed beamforming at each hop. We use simulation to demonstrate that our link cost preserves anonymity and reduces energy consumption to levels below those of WSNs that employ no anonymity protection.