Cross-Layer Designs for Energy-Efficient Sensor Networking

We propose a novel architecture for large-scale, low power sensor networks, referred to as Sensor Networks with Mobile Agents (SENMA) utilizing an Ultra Wide Band physical (PHY) layer. SENMA is designed to exploit node redundancies by introducing mobile agents that communicate opportunistically with a large field of sensors. The addition of mobile agents shifts computationally intensive tasks away from primitive sensors to more powerful mobile agents, which enables energy efficient operations under severely limited power constraints. Additionally, we select the Ultra Wide Band PHY layer to exploit mutual non-interfering operation and its natural by-product of range information. We further propose a cross-layer approach of PHY and MAC layers to provide power efficiency and operation effectiveness over SENMA architecture, referred as an Opportunistic ALOHA. Finally, using randomly selected CDMA codes from a large table of orthogonal codes will further reduce the complexity associated with collision mitigation. A comparison and analysis of SENMA with a flat ad-hoc sensor network architecture will be comprehensively conducted regarding the energy efficiency.