Hardware and Software Architecture of Wireless Sensor Networks

Abstract

Conventional RF Wireless receivers, Bluetooth, Zigbee, 802.11 consume tens to hundreds of mW of battery power when operational. We consider this problem and format a solution for it. The only way by which the power budget needed for wireless sensor networks can be met is to organize the network such that the receivers are rarely switched on. The intermittent operation requires that the terminals have a sufficiently accurate common view of time to be able to switch on at correct moment. In many contexts this places unreasonable constraints on the distribution of timing within the network and the time-keeping ability of the terminals themselves. In event driven networks, where long idle periods are punctuated by occasional feverish activity, the overhead in maintaining synchronization can be unacceptable. Our motivation in designing the terminals described here is to get to a place where intermittent operation is no longer essential. In this mode of operation (the 'always on' receiver) a terminal that has something to say can do so immediately, knowing that its neighbors will be listening. The simplicity of this physical layer transaction has far reaching ramifications in the networking protocols and the level of network timing that has to be maintained; a further reduction in energy utilization comes about as a result. This whitepaper illustrates the basic hardware/software requirements as well as actual hierarchical development of the wireless sensor networks. It also includes the applications of wireless sensor network in the real world environment.