The University of Iowa. Copyright© 2005 A. Kruger 1 Introduction to Wireless Sensor Networks ZigBee Overview 24 February 2005

The University of Iowa. Copyright© 2005 A. Kruger 2 Organizational Monday 4:30-5:20Room 4511 SC Thursday12:30-1:20Room 3220 SC Please note that the room numbers are different for Mondays and Thursdays. Class Website Class Time Midterm Exam Time: March 10, 2005

The University of Iowa. Copyright© 2005 A. Kruger 3 What is ZigBee? “Internet Everything” –Your toaster gets an IP address Wireless standard formed by an alliance of industry leaders Motorola, Phillips, Samsung, Cisco… over 100 companies!!

The University of Iowa. Copyright© 2005 A. Kruger 4 Why ZigBee? Reliable and self healing Supports large number of nodes Easy to deploy Very long battery life Secure Low cost Can be used globally

The University of Iowa. Copyright© 2005 A. Kruger 5 Applications ZigBee Wireless Control that Simply Works RESIDENTIAL/ LIGHT COMMERCIAL CONTROL CONSUMER ELECTRONICS TV VCR DVD/CD remote security HVAC lighting control access control lawn & garden irrigation PC & PERIPHERALS INDUSTRIAL CONTROL asset mgt process control environmental energy mgt PERSONAL HEALTH CARE BUILDING AUTOMATION security HVAC AMR lighting control access control mouse keyboard joystick patient monitoring fitness monitoring

The University of Iowa. Copyright© 2005 A. Kruger 6 – “the software” – Network, Security & Application layers – Brand management IEEE – “the hardware” – Physical & Media Access Control layers PHY 868MHz / 915MHz / 2.4GHz MAC Network Star / Mesh / Cluster-Tree Security 32- / 64- / 128-bit encryption Application API ZigBee Alliance IEEE Customer Silicon Stack App IEEE & ZigBee In Context

The University of Iowa. Copyright© 2005 A. Kruger 7 Why IEEE ? Ultra Low complexity Ultra Low cost Ultra Low power consumption Data reliability Low data rate

The University of Iowa. Copyright© 2005 A. Kruger General Characteristics Data rates of 20 kbps and up to 250 kbps Star or Peer-to-Peer network topologies Support for Low Latency Devices CDMA-CA Channel Access Handshaking Low Power Usage consumption 3 Frequencies bands with 27 channels Extremely low duty-cycle (<0.1%)

The University of Iowa. Copyright© 2005 A. Kruger Frequency Bands BAND COVERAGE DATA RATE CHANNELS 2.4 GHz ISM Worldwide 250 kbps MHz ISM Americas 40 kbps MHz Europe 20 kbps 1

The University of Iowa. Copyright© 2005 A. Kruger 10 Channel Division 868MHz/ 915MHz PHY 2.4 GHz MHz Channel 0 Channels 1-10 Channels GHz 928 MHz902 MHz 5 MHz 2 MHz 2.4 GHz PHY

The University of Iowa. Copyright© 2005 A. Kruger 11 Modulation & Spreading Direct Sequence Spread Spectrum (DSSS) –Chipping Sequences 2.4 GHz –32-chip PN codes –Chip modulation is MSK at 2.0 Mchips/s 868/915 MHz –15-chip m-sequence –Chip modulation is BPSK at 0.3 Mchips/s

The University of Iowa. Copyright© 2005 A. Kruger 12 Media Access Control Code Division Media Access w/ Collision Avoidance (CDMA-CA) Bi-Directional Communications (Duplex) Dynamic Device Addressing Fully Handshaked Protocol Optional Guaranteed Time Slots 2.4 GHz - 16-ary orthogonal 868/915 MHz - differential encoding

The University of Iowa. Copyright© 2005 A. Kruger 13 Packet Structure Packet Fields –Preamble (32 bits) - synchronization –Start of Packet Delimiter (8 bits) - specifies one of 3 packet types –PHY Header (8 bits) - Sync Burst flag, PSDU length –PSDU (0 to 127 bytes) - Data Preamble Start of Packet Delimiter PHY Header PHY Service Data Unit (PSDU) 6 Bytes0-127 Bytes

The University of Iowa. Copyright© 2005 A. Kruger 14 Transceiver Characteristics Transmit Power –Capable of at least 1 mW –Power reductions capability required if > 16 dBm (reduce to < 4dBm in a single step) Receiver Sensitivity –-85 dBm (1 % Packet Error Rate) RSSI measurements –Packet Strength indication –Clear channel assessment –Dynamic channel selection

The University of Iowa. Copyright© 2005 A. Kruger 15 PHY Layer Primitives PHY Data Service –PD-DATA - exchange data packets between MAC and PHY PHY Management Service –PLME-CCA - clear channel assessment –PLME-GET - retrieve PHY parameters –PLME-RX-ENABLE - enable/disable receiver –PLME-SET - set PHY parameters

The University of Iowa. Copyright© 2005 A. Kruger 16 Basic Network Characteristics 65,536 network (client) nodes Optimized for timing-critical applications –Network join time: 30 ms (typ) –Sleeping slave changing to active: 15 ms (typ) –Active slave channel access time: 15 ms (typ) Network coordinator Full Function node Reduced Function node Communications flow Virtual links

The University of Iowa. Copyright© 2005 A. Kruger 17 Topology Models (cont) Star Networks (Personal Area Network) –Home automation –PC Peripherals –Personal Health Care Peer-to-Peer (ad hoc, self organizing & healing) –Industrial control and monitoring –Wireless Sensor Networks –Intelligent Agriculture

The University of Iowa. Copyright© 2005 A. Kruger 18 Topology Models PAN coordinator Full Function Device Reduced Function Device Star Mesh Cluster Tree

The University of Iowa. Copyright© 2005 A. Kruger 19 Device Classes Full function device (FFD) –Any topology –Network coordinator capable –Talks to any other device Reduced function device (RFD) –Limited to star topology –Cannot become a network coordinator –Talks only to a network coordinator –Very simple implementation

The University of Iowa. Copyright© 2005 A. Kruger 20 Comparison of complimentary protocols

The University of Iowa. Copyright© 2005 A. Kruger 21 Bluetooth 30 days (park 1.28s) /ZigBee more battery-effective at all beacon intervals greater than 0.246s At beacon interval ~1s, 15.4/ZigBee battery life 85 days At beacon interval ~60s, 15.4/ZigBee battery life approx 416 days /ZigBee vs Bluetooth

The University of Iowa. Copyright© 2005 A. Kruger 22 Device Addressing All devices have IEEE addresses Short addresses can be allocated Addressing modes: –Network + device identifier (star) –Source/destination identifier (peer-peer) –Source/destination cluster tree + device identifier (cluster tree)

The University of Iowa. Copyright© 2005 A. Kruger 23 General Data Packet Structure PRESPDLENPCCRCLink Layer PDUADDRESSING Preamble sequence Start of Packet Delimiter Length for decoding simplicity Flags specify addressing mode Data sequence number CRC-16 DSN Addresses according to specified mode

The University of Iowa. Copyright© 2005 A. Kruger 24 Optional Frame Structure 15ms * 2 n where 0  n  14 Network beacon Contention period Beacon extension period Transmitted by network coordinator. Contains network information, frame structure and notification of pending node messages. Space reserved for beacon growth due to pending node messages Access by any node using CSMA-CA GTS 3GTS 2 Guaranteed Time Slot Reserved for nodes requiring guaranteed bandwidth [n = 0]. GTS 1

The University of Iowa. Copyright© 2005 A. Kruger 25 Traffic Types Periodic data –Application defined rate (e.g. sensors) Intermittent data –Application/external stimulus defined rate (e.g. light switch) Repetitive low latency data –Allocation of time slots (e.g. mouse)

The University of Iowa. Copyright© 2005 A. Kruger 26 Development Boards Atmel –AT86RF210 Z-Link™ Transceiver is an 868/915 MHz direct sequence spread spectrum BPSK transceiver designed for IEEE /ZigBee™- based systems; supports data rates of 20 kbps and 40 kbps, respectively. –AT86ZL3201 Z-Link™ Controller is an 8-bit AVR® Microcontroller customized for IEEE /ZigBee™ for wireless monitor and control applications; supports the 868/915 MHz and 2.4 GHz bands with data rates of 20 kbps, 40 kbps, and 250 kbps, respectively.

The University of Iowa. Copyright© 2005 A. Kruger 27 Development Boards (cont.) MicroChip PICDEM Z Demonstration kit –Features: ZigBee software stack supporting RFD (Reduced Function Device), FFD (Full Function Device) and Coordinator PIC18LF4620 MCU featuring nanoWatt Technology, 64 KB Flash memory and robust integrated peripherals RF transceiver and antenna interface via daughter card for flexibility Supports 2.4 GHz frequency band via Chipcon CC2420 RF transceiver Temperature sensor (Microchip TC77), LEDs and button switches to support demonstration –Package Contents Two PICDEM Z demonstration boards each with an RF transceiver daughter card ZigBee protocol stack source code (on CD ROM)

The University of Iowa. Copyright© 2005 A. Kruger 28 Development Boards (cont.) Motorola/FreeScale 13192DSK –Two 2.4 GHz wireless nodes compatible with the IEEE standard MC GHz RF data modemMC13192 MC9S08GT60 low-voltage, low-power 8-bit MCU for baseband operationsMC9S08GT60 Integrated sensors –MMA6261Q 1.5g X-Y-axis accelerometerMMA6261Q –MMA1260D 1.5g Z-axis accelerometerMMA1260D Printed transmit-and-receive antennae Onboard expansion capabilities for external application-specific development activities Onboard BDM port for MCU Flash reprogramming and in-circuit hardware debugging RS-232 port for monitoring and Flash programming

The University of Iowa. Copyright© 2005 A. Kruger 29 Development Boards (cont.) Emulator Development Kits –Ember –CompXs –Helicomm

The University of Iowa. Copyright© 2005 A. Kruger 30 Low Data Rate Wireless Evolution  Proprietary Fades  ZigBee Emerges  Semiconductor Focus  Early Adopter OEMs  $1 - $10B Industry  $100 - $10 Unit Cost Second Stage  Standards Dominate  IEEE Emerges  OEM Focus  Wireless Ubiquitous  $10 - $100B+ Industry  $10 - $1 Unit Cost Third Stage First Stage ………  Proprietary Dominates  IEEE Emerges  System Integrator Focus  Leading Edge OEMs  $.1 - $1B Industry  $1,000 - $100 Unit Cost Mapping Your Future: From Data to Value AMRA 2003 International Symposium

The University of Iowa. Copyright© 2005 A. Kruger 31 References The ZigBee Alliance web site – –Bob Heile, ZigBee Alliance Chairman Helicomm, Inc. Atmel, Inc. Microchip, Inc. Motorola, Inc. Thanks to Ryan Braun!