WIRELESS SENSOR NODE WITH LOW-POWER SENSING

Wireless sensor network consists of a large number of simply sensor nodes that collect information from the external environment by sensors, process the information, and communicate with other neighboring nodes in the network. Usually sensor nodes operate with exhaustible batteries unattended. Since manual replacement or recharging the batteries is not an easy, desirable and always possible task, the power consumption becomes a very important issue in the development of these networks. The total power consumption of a node is a result of all steps of operation: sensing, data processing and radio transmission. In this work we focus on the impact of sensing hardware on the total power consumption of a sensor node. Firstly, we describe the structure of sensor node architecture, identify its key energy consumption sources, and introduce an energy model for the sensing subsystem as building block of a node. Secondly, with aim to reduce energy consumption of a node we propose implementation of two power-saving techniques: duty-cycling and power-gating. Duty-cycling is effective at system level. It is used for switching a node between active and sleep mode (with duty-cycle factor of 1% reduction of in dynamic energy consumption is achieved). Power-gating is implemented at circuit level with goal to decrease a power loss due to leakage current (in our design, a reduction of dynamic and static energy consumption of off-chip sensor elements as constituents of sensing hardware within a node of is achieved). Our MATLAB simulation results suggest that in total for a sensing hardware thanks to involving of duty-cycling and power-gating secures a three order of magnitude reduction ( ) in energy consumption can be achieved compared to a node architecture in which the implementation of both energy saving techniques are omitted