ABSTRACT
The design of a wireless sensor network is more than the design of a communication protocol. The design of the actual network nodes is critical to the success of the network (i.e., to how well the network meets the needs of the application). Several features of the design of wireless sensor network nodes are unique (or nearly so) to the design of small, battery-powered wireless devices, and are not often encountered in the design of other types of electronic equipment. For example, in the design of a cellular telephone or other land mobile communications system, the primary cost to be borne in mind during development is the cost of the system infrastructure — the base stations, towers, switching equipment, etc. — both as an initial capital outlay and then as monthly rental, depreciation, and maintenance expense. To make the system economically viable, this equipment must service the largest possible number of users to defray these fixed costs among them to the point that the service is affordable. The cost of the individual mobile handset is, to a very large degree, irrelevant when compared with the infrastructure cost; not only is its cost relatively low when compared with the infrastructure cost, its maintenance cost is also negligible — and often borne by the user, in any event, in the form of electricity to recharge the battery.
