IEEE 802.11 (Wi-Fi) is normally used to provide high-speed, moderate-range IP data transfer between computers or handheld devices and local-area-networks, where datarate is the main design parameter. Systems optimized for this applica-tion are fast but not energy-efficient. However, with appropriate system design and usage models, Wi-Fi devices can operate in a power-efficient fashion, and achieve multi-year battery life in sensors and other low-power applications. Low-power Wi-Fi devices have the advantages of native IP-network compatibility and well-known protocols and management tools.
Sensors that monitor a variety of physical world conditions such as thermal, mechanical, chemical, optical, acoustical, and other measurable parameters, have long been employed in a variety of industrial, commercial, public, and consumer applications. Utilizing wireless technologies for sensor network solutions affords the potential for new capabilities and increased efficiencies. Today various proprietary wireless solutions exist for sensor network applications such as 802.15.4 based implementations; however, there is yet to be a widely deployed standards-based solution, or even a de facto standard per market penetration. At the same time IEEE 802.11 networks are widely deployed for commercial, public, and consumer applications, having met criteria for such requirements as security, manageability, and cost, but their use in sensor networks has been limited because many applications require years-long battery life for sensors node devices. New 802.11 designs that meet battery life requirements for sensor nodes enable organizations to capitalize on the their existing 802.11 infrastructure investment with the benefits that generally come with standards-based solutions, such as lower costs due to economies of scale, interoperability, ease of use, and availability of mature management tools, as well as the ability to support other 802.11 client devices.