Essay Example on The Wireless Personal Area Networks WPANs is covered by this Group

The Wireless Personal Area Networks WPANs is covered by this group Communications specification that was approved in early 2002 by the IEEE for wireless personal area networks Different technologies are covered by several subgroups 2 802 15 1 Bluetooth based Short range 10m wireless technology for cordless keyboard mouse and hands free headset at 2 4 GHz 3 802 15 3a To provide a higher speed Ultra wideband UWB PHY enhancement amendment to IEEE 802 15 3 for applications which involve imaging and multimedia Short range high bandwidth ultra wideband link This was withdrawn in January 2006 4 802 15 4 ZigBee Short range wireless sensor networks IEEE 802 15 4 is a technical standard covering the operation of low rate wireless personal area networks LR WPANs This standard was defined in 2003 and maintained by the IEEE 802 15 working group it covers the physical layer and media access control for LR WPANs It forms the basis for the ZigBee ISA100 11a WirelessHART MiWi SNAP Thread specifications each of which further extends the standard by developing the upper layers which are not defined in IEEE 802 15 4 It can also be used with 6LoWPAN the technology used to deliver the IPv6 version of the Internet Protocol IP over WPANs to define the upper layers 5 IEEE 802 15 5 Mesh Network Extension of network coverage without increasing the transmit power or the receiver sensitivity Enhanced reliability via route redundancy Easier network configuration Better device battery life 6 802 15 5 provides the architectural framework enabling WPAN devices to promote interoperable stable and scalable wireless mesh networking It is composed of two parts i low rate WPAN mesh less which is built on IEEE 802 15 4 2006 MAC and ii high rate WPAN mesh networks which utilize IEEE 802 15 3 3b 

An important feature of the physical layer is the use of a dual ring topology using optical fiber at high data rates up to 1 Gbps or more Data can be transmitted simultaneously on both rings in normal operation doubling the capacity Robustness is provided by the dual ring topology by including a capability for automatic reconfiguration after a link failure 6 The main purpose is to provide enhanced services for the transmission of Ethernet packets over a ring based interconnect topology at the MAC level This means a simple mapping from the Ethernet frame format to the RPR frame format 7 RPR runs on a concept of dual counter rotating rings referred to as ringlets These ringlets are set up by creating RPR stations at nodes where traffic is supposed to drop per flow a flow is the ingress and egress of data traffic Media Access Control protocol MAC messages to direct the traffic is used by RPR which can use either ringlet of the ring The nodes also negotiate for bandwidth among themselves using fairness algorithms avoiding congestion failed spans Failed spans are avoided by using one of two techniques known as steering wrapping All nodes are notified of a topology change they reroute their traffic if a node or span is broken under steering The traffic is looped back in wrapping at the last node before the break routed to the destination station