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Unit V- Wireless communication. Prepared by, S.Sankara Narayanan. Asst Professor/CSE Ssankaranarayanan.wordpress.com. outline. IEEE 802.11 Wireless geolocation Mobile Adhoc Networks IEEE 802.15 Home RF Bluetooth technology. IEEE 802.11.
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Unit V- Wireless communication Prepared by, S.Sankara Narayanan. Asst Professor/CSE Ssankaranarayanan.wordpress.com
outline IEEE 802.11 Wireless geolocation Mobile Adhoc Networks IEEE 802.15 Home RF Bluetooth technology Wireless communication/ECE431
IEEE 802.11 Supports both infrastructure WLAN connecting through an AP and ad hoc operation allowing peer to peer communication between terminals. Wireless communication/ECE431
Requirements The standard should provide Single MAC to support multiple PHY layers. mechanisms to handle hidden terminals. options to support time bounded services provisions to handle privacy and access control. Wireless communication/ECE431
Reference architecture Basic service area-coverage area of one access point. Basic service set-set of stations controlled by one AP. Distribution system – is fixed infrastructure used to connect set of BSS to create extended service set(ESS) Wireless communication/ECE431
Protocol architecture Wireless communication/ECE431
Contd… MAC Sublayer- responsible for access mechanism and fragmentation and reassembly of packets. Management sub layer – responsible for roaming in ESS, power management, association,disassociation for registration connection management. Wireless communication/ECE431
PHY layer PHY layer convergence protocol(PLCP) PHY medium dependent protocol(PMD) PHY management sublayer Wireless communication/ECE431
Contd.. PLCP responsible for carrier sensing assessment and forming packets for different PHY layers. PMD sublayer specifies the modulation and coding technique for signalling with the medium. PHY layer management decides on channel tuning to different options for each PHY layer. Wireless communication/ECE431
Wireless Geo location Wireless communication/ECE431
Functional architecture Two functional ingredients of position location are location estimation of MS attributes shared with network N Wireless communication/ECE431
Contd…. There are two ways in which actual estimation of location can be obtained. Self positioning system Remote positioning system. Wireless communication/ECE431
Self positioning system MS locates its own position using measurements of its distance or directions from known locations of transmitters. Wireless communication/ECE431
Remote positioning system Receivers at known locations on a network together compute location of a mobile transmitter using the measurements of the distance or direction of this mobile from each of the receivers. Wireless communication/ECE431
Mobile Adhoc Networks Wireless communication/ECE431
Wireless Personal Area Networks IEEE 802.15 WPAN Wireless communication/ECE431
HOME RF Wireless communication/ECE431
Mission The HomeRF working group was formed to establish the mass deployment of interoperable wireless networking access devices to both local content and internet voice, data and streaming media in consumer environments
Vision Set up a wireless home network to share voice and data between PCs, peripherals, PC enhanced cordless phones etc Access internet from anywhere in and around the home from portable display devices Share ISP connection between PCs and other new devices
Member Companies HRFWG includes leading companies from the personal computer, consumer electronics, peripherals, communications, software and semiconductor industries HRFWG has developed a specification for wireless communication in home called the Shared Wireless Access Protocol (SWAP)
SWAP The HomeRF SWAP is designed to carry both voice and data traffic and to interoperate with the PSTN and the Internet Operates in the 2.4GHz ISM range Uses digital frequency hopping spread spectrum – 50 hops / second Provides 1 Mbps and 2 Mbps data rate
SWAP Technology • Extensions of DECT ( Digital Enhanced Cordless Telephone ) and wireless LAN technology to enable a new class of home cordless services
Network topology SWAP system operates in either Ad hoc network Managed network Ad hoc Network Only data communication is supported All stations are equal Control of network distributed between the stations
Network topology Managed network For time critical applications such as interactive voice, Connection point is required to coordinate the system The Connection point provides the gateway to the PSTN and can be connected to a PC via a standard interface like USB that will enable voice and data services
Managed network The Connection point also provides power management for prolonged battery life by scheduling device wakeup and polling
Node types The network can accommodate up to 127 nodes There are 4 basic types of nodes Connection point – supports voice and data Voice terminal – uses TDMA to communicate with base station Data node – uses CSMA/CA to communicate with a base station and other data nodes Voice and data node – uses both types of services
What is Bluetooth? A cable-replacement technology that can be used to connect almost any device to any other device Radio interface enabling electronic devices to communicate wirelessly via short range (10 meters) ad-hoc radio connections a standard for a small , cheap radio chip to be plugged into computers, printers, mobile phones, etc