L weakness in today's systems is their susceptibility to access, with additional flexibility. The current telecom optical blockage, particularly from fog. slump has slowed the deployment of these systems. Local area systems VSAT and other geosynchronous satellite systems Unlike the fixed systems just considered, local area sys- Very small aperture terminal (VSAT) systems are similar tems achieve their high throughput via proximity. They to fixed terrestrial multipoint systems, except that in- generally allow some range of motion on the user's part, stead of a tower- or rooftop-mounted base unit, a satellite providing flexible usage scenarios. The technologies transponder is used. A limited number of geo- considered here require no spectrum license. synchronous earth orbit (GEO) satellites circle the equator at 22,236 miles altitude, maintaining a fixed Infrared, IrDA position in relation to a point on the earth. These tran- Infrared signals are used for a range of simple control sponders can be used for high-bandwidth bidirectional protocols, such as TV remote controls. The Infrared Data signal relay, supporting applications such as data transfer, Association (IrDA) has standardized multimegabit-per- Internet access, and audio/video signal distribution. second data transfers in support of a wide range of usage Though the ground station antenna is fixed during oper- profiles. Typically, these are very short-range (i.e., inches ation, it is easily deployable, making it well suited for to feet of separation between units) applications re- disaster recovery and other temporary situations. quiring a fairly high degree of directionality between Again, multiple licensed bands are employed. Full transmitter and receiver. According to IrDA [4], over satellite channels are often subdivided via multiple access 300 million devices support this technology. Introduction CHAPTER 1.0 Bluetooth personal area networks Paging Operating at 1 Mbps channel rate in the unlicensed 2.4 Paging was successful for years as a reliable delive