无线传感器节点（智能手环、智能手表）

A Wireless Sensor Network (WSN) consists of autonomous devices with inbuilt sensors for monitoring various environmental and physical conditions at various places and times. These devices have traditionally been networked using the IEEE 802.15.4 standard as the base with standards like Zigbee, 6LoWPAN, WirelessHART, etc., forming the upper layers. These standards have served well the primary requirement of Wireless Sensor Nodes - a long battery life. However, they have their drawbacks - they offer limited range and throughput, they are less secure, they need special infrastructure so that they can be integrated into the existing LAN and they are affected by an already existing WLAN since they use the same frequency band. Wi-Fi addresses these issues effectively and WSN's have started using 802.11b/g /n as the networking standard. The RS9113/RS9116/RS14100 module is a complete IEEE802.11bgn Wi-Fi client device with an integrated MAC, baseband processor, RF transceiver and power amplifier. Based on the Redpine's RS9113/RS9116/RS14100 MAC/baseband processor, the module provides a complete end-to-end solution for ultra low power WLAN applications. It conforms to the 802.11n standard in single-stream mode for handheld devices and includes an embedded processor with a rich set of peripherals offering minimal load on a host processor, to which it can connect through SDIO and SPI interfaces. Since this module doesn't support IPv6 it can only be used in small to medium scale number of sensor nodes applications.