 WLANs Agriculture-Micromeshes can be used for soil monitoring, water manage- ment, chemical deployment, and other uses in agriculture. Applications requiring mobility-Micromeshes can be used in situations in which it is frequently necessary to move the entire network, such as in military, intelligence, and national security environments. For example, imagine a horse ranch with sensors, each the size of a quarter, dis- persed over the land, measuring environmental variables such as temperature and humidity. If each sensor were connected to a base station, the cost would be pro- hibitive, but in a micromesh network, they are all connected to each other and then to the base station. They synchronize with each other, collect data, and sleep until the next iteration. As illustrated in Figure 15.6, a sensor mesh network must bridge to processing elements that deal with the data collected by sensor nodes. It must also provide monitoring and command and control of the mesh in response to changing condi- tions. This functionality is best implemented in a gateway. As the size of a micromesh network grows, there is increasing need for a gateway-based systems- level architecture. It is predicted that gateways will become a core element of sen- sor-mesh networks in the coming years. 000000000000 PC Remote Station Gateway Node Sensor Nodes Mobile Tablet Mesh Node (Router) Wireless Links Database Figure 15.6 A sensor mesh network Chapter 15 WMANs, WLANs, and WPANs WPANs A WPAN is a network that serves a single person or small workgroup and is charac- terized by limited distance, limited throughput, and low volume. PANs have tradi- tionally been used to transfer data between a laptop or PDA and a desktop machine or server and a printer. In this case, there is usually support for virtual docking sta- tions, peripheral sharing, and ad hoc infrared links. Another application of WPANs is in support of building automation and control. An increasing number of machine- to-machine (m2m) applications are emerging, as are future applicat