IEEE

Wireless Personal Area Networks Wireless networks classified into four broad categories: –Wireless personal area network (WPAN): Hand-held and portable devices; slow to moderate transmission speeds. –Wireless local area network (WLAN): i.e., IEEE a/b/g –Wireless metropolitan area network (WMAN): Range up to 50 kilometers –Wireless wide area network (WWAN): Connects networks in different geographical areas

Wireless Personal Area Networks (continued)

Point-to-point transmission

Wireless Personal Area Networks (continued) Point-to-multipoint transmission

Wireless Personal Area Networks WPANs encompass technology designed for portable devices –PDAs, cell phones, tablet or laptop computers –Low transmission speeds Three main categories: –IEEE standards –Radio frequency ID (RFID) –IrDA

WPANs: IEEE (Bluetooth) Bluetooth uses short-range RF transmissions –Users can connect wirelessly to wide range of computing and telecommunications devices –Rapid and ad hoc connections between devices adapted and expanded from Bluetooth –Designed for area of about 10 meters –Rate of transmission below 1 Mbps Two types of network topologies –Piconet –Scatternet

WPANs: IEEE (continued) Piconet: When two devices come within range, automatically connect –Master: Controls wireless traffic –Slave: Takes commands from master –Piconet has one master and at least one slave Active slave: Connected to piconet and sending transmissions Parked slave: Connected but not actively participating

WPANs: IEEE (continued) Piconet

WPANs: IEEE (continued) Devices in piconet can be in one of five modes: –Standby: Waiting to join a piconet –Inquire: Device looking for devices to connect to –Page: Master device asking to connect to specific slave –Connected: Active slave or master –Park/Hold: Part of piconet but in low-power state Scatternet: Group of piconets in which connections exist between different piconets uses FHSS

WPANs: IEEE (continued) Scatternet

WPANs: IEEE Created in response to limitations of –High-rate WPANs Two main applications: –Video and audio distribution for home entertainment systems High-speed digital video transfer Home theater PC to LCD projector Interactive video gaming –High speed data transfer

WPANs: IEEE (continued) Differences between and –Quality of Service (QoS) –Security –High data rates –Spectrum utilization IEEE security modes

WPANs: IEEE (continued) a: Will support data transfers up to 110 Mbps between max of 245 devices at 10 meters –Ultrawideband (UWB) –Intended to compete with USB 2.0 and FireWire IEEE b task group working on improving implementation and interoperability of IEEE c task group developing alternative physical layer standard that could increase speeds up to 2 Gbps

WPANs: IEEE Sometimes preferable to have low-speed, low-power wireless devices –Size can be dramatically reduced IEEE standard addresses requirements for RF transmissions requiring low power consumption and cost IEEE data rates and frequencies

WPANs: IEEE (continued) ZigBee Alliance: Industry consortium that promotes standard ZigBee and IEEE

WPANs: Radio Frequency ID (RFID) RFID tag

WPANs: Radio Frequency ID (continued) Passive RFID tags: No power supply –Can be very small –Limited amount of information transmitted Active RFID tags: Must have power source –Longer ranges/larger memories than passive tags RFID tags

WPANs: IrDA Infrared Data Association IrDA specifications include standards for physical devices and network protocols they use to communicate Devices communicate using infrared light-emitting diodes –Recessed into device –Many design considerations affect IrDA performance

WPANs: IrDA (continued) IrDA drawbacks: –Designed to work like standard serial port on a personal computer, which is seldom used today –Cannot send and receive simultaneously –Strong ambient light can negatively impact transmissions –Angle and distance limitation between communicating devices