GEPS Programming Tutorial

LOW POWER WI-FI™ (IEEE 802.11) FOR IP SMART OBJECTS Daniel M. Dobkin and Bernard Aboussouan GainSpan Corporation Abstract: 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. LOW-POWER WI-FI™ FOR IP SMART OBJECTS Introduction Until recently, Wi-Fi was not considered viable for battery powered sensor network applications. Wi-Fi silicon had been targeted at laptops and cell phones, where the battery can be recharged after several hours of operation, or at line-powered devices such as access points. With the growing market for smart objects and wireless sensors, companies such as GainSpan have developed application-specific integrated circuits that are optimized for sensing applications. These products achieve a similar power profile to other low power wireless PHY/ MAC architectures, while leveraging the benefits of a well-established protocol: ► A huge installed base of over 2 ...