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IEEE 802.15.4 Draft Standard. Presented by Arsalan Tavakoli CS 294 -11 October 18, 2005. Introduction. Home Networking Application Classes Internet connectivity Multi-PC Connectivity Audio/Video Networking Home Automation Energy Conservation Security. Motivation.
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IEEE 802.15.4 Draft Standard Presented by Arsalan Tavakoli CS 294 -11 October 18, 2005
Introduction • Home Networking Application Classes • Internet connectivity • Multi-PC Connectivity • Audio/Video Networking • Home Automation • Energy Conservation • Security
Motivation • Personal Area Network Requirements • Low Power Consumption • Minimal Installation Cost • Low Overall Cost • Existing Technologies • Wired • 802.11 • Bluetooth
History of Development • Combination of Two Standards Groups • ZigBee Alliance • IEEE 802 Working Group 15 • Task Group 4 formed in December 2000 • Low-rate Wireless Personal Area Network • Focus only on Physical and MAC layer specifications
Network Layer Guidelines • 802.15.4 Specification does not address Network Layer • Expected to be self-organizing and self-maintaining to minimize cost to user • Two Network Topologies Supported: • Star Topologies • Peer-to-Peer Topologies
Data Link Layer • Two Parts • Logical Link Control (LLC) • Standard among many 802.x standards • Communicates with MAC through SSCS • Proprietary LLC’s can communicate directly • MAC Sublayer • Data Service - Common Part Sublayer • Management Service – Management Entity
Superframe Beacons • Time between beacons divided in 16 time slots • Can be used to provide bandwidth guarantees • Contention-free period and duration of superframe announced in beacon
Additional MAC Features • Channel Access Mediums • Slotted CSMA-CA • Unslotted CSMA-CA • Acknowledgements • Security • No security • Access Control Lists • Symmetric Key Security
Physical Layer • Two Potential Physical Layers • 868/915Mhz • 2.4Ghz • Direct Sequence Spread Spectrum • Same Packet Structure • 27 Frequency Channels Total • Dynamic Channel Selection left to network layer
Other Physical Layer Features • Modulation • 868/915 – Binary Phase Shift Keying • 2.4 – Offset Quadrature Phase Shift Keying • Sensitivity and Range • 868/915 -92 dBm • 2.4 -85 dBm • 10-20m typical range