Transcript Wireless Sensor Networks - User page server for CoE

Introduction to Wireless
Sensor Networks
ZigBee Overview
24 February 2005
The University of Iowa.
Copyright© 2005
1
A. Kruger
Organizational
Class Website
www.engineering.uiowa.edu/~ece195/2005/
Class Time
Monday
4:30-5:20
Room 4511 SC
Thursday
12:30-1:20
Room 3220 SC
Please note that the room numbers are different for
Mondays and Thursdays.
Midterm Exam
Time: March 10, 2005
The University of Iowa.
Copyright© 2005
2
A. Kruger
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
3
A. Kruger
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
4
A. Kruger
Applications
security
HVAC
AMR
lighting control
access control
patient
monitoring
fitness
monitoring
BUILDING
AUTOMATION
CONSUMER
ELECTRONICS
TV
VCR
DVD/CD
remote
ZigBee
PERSONAL
HEALTH CARE
asset mgt
process
control
environmental
energy mgt
The University of Iowa.
Copyright© 2005
Wireless Control that
Simply Works
RESIDENTIAL/
LIGHT
COMMERCIAL
CONTROL
INDUSTRIAL
CONTROL
5
PC &
PERIPHERALS
mouse
keyboard
joystick
security
HVAC
lighting control
access control
lawn & garden irrigation
A. Kruger
IEEE 802.15.4 & ZigBee In Context
Application
Customer
API
Security
– “the software”
32- / 64- / 128-bit encryption
Network
ZigBee
Alliance
– Brand management
Star / Mesh / Cluster-Tree
IEEE 802.15.4
MAC
IEEE
802.15.4
PHY
868MHz / 915MHz / 2.4GHz
Silicon
The University of Iowa.
Copyright© 2005
Stack
– Network, Security &
Application layers
– “the hardware”
– Physical & Media
Access Control layers
App
6
A. Kruger
Why IEEE 802.15.4?
•
•
•
•
•
Ultra Low complexity
Ultra Low cost
Ultra Low power consumption
Data reliability
Low data rate
The University of Iowa.
Copyright© 2005
7
A. Kruger
802.15.4 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
8
A. Kruger
802.15.4 Frequency Bands
BAND COVERAGE
2.4 GHz
ISM
Worldwide
915 MHz
ISM
868 MHz
The University of Iowa.
Copyright© 2005
DATA RATE
CHANNELS
250 kbps
16
Americas
40 kbps
10
Europe
20 kbps
9
1
A. Kruger
Channel Division
868MHz/
915MHz
PHY
2.4 GHz
PHY
Channel 0
Channels 1-10
868.3 MHz
902 MHz
Channels 11-26
2.4 GHz
The University of Iowa.
Copyright© 2005
2 MHz
928 MHz
5 MHz
2.4835 GHz
10
A. Kruger
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
11
A. Kruger
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
12
A. Kruger
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 Bytes
The University of Iowa.
Copyright© 2005
0-127 Bytes
13
A. Kruger
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
14
A. Kruger
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
15
A. Kruger
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
16
A. Kruger
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
17
A. Kruger
Topology Models
Mesh
Star
PAN coordinator
Full Function Device
Reduced Function Device
Cluster Tree
The University of Iowa.
Copyright© 2005
18
A. Kruger
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
19
A. Kruger
Comparison of complimentary
protocols
Feature(s)
IEEE 802.11b
Bluetooth
ZigBee
Power Profile
Complexity
Nodes/Master
Hours
Very Complex
32
Years
Simple
64000
Latency
Enumeration upto 3 seconds
Enumeration 30ms
Range
Extendability
Data Rate
100 m
Roaming possible
11Mbps
Days
Complex
7
Enumeration upto 10
seconds
10m
No
1Mbps
Security
Authentication Service Set
ID (SSID)
64 bit, 128 bit
128 bit AES and Application
Layer user defined
The University of Iowa.
Copyright© 2005
20
70m-300m
YES
250Kbps
A. Kruger
802.15.4/ZigBee vs Bluetooth
At beacon interval ~6
15.4/ZigBee battery
approx 416 days
802.15.4/ZigBee more
battery-effective at all beacon
intervals greater than 0.246s
At beacon interval ~1s,
15.4/ZigBee battery life 85
days
Bluetooth 30 days
(park mode @ 1.28s)
The University of Iowa.
Copyright© 2005
21
A. Kruger
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
22
A. Kruger
General Data Packet Structure
Preamble sequence
Start of Packet Delimiter
PRE
SPD
LEN
PC
ADDRESSING
DSN
Link Layer PDU
CRC
CRC-16
Data sequence number
Addresses according to specified mode
Flags specify addressing mode
Length for decoding simplicity
The University of Iowa.
Copyright© 2005
23
A. Kruger
Optional Frame Structure
GTS 3
GTS 2
GTS 1
15ms * 2n
where 0  n  14
Network
beacon
Transmitted by network coordinator. Contains network information,
frame structure and notification of pending node messages.
Beacon
extension
period
Space reserved for beacon growth due to pending node messages
Contention
period
Access by any node using CSMA-CA
Guaranteed
Time Slot
Reserved for nodes requiring guaranteed bandwidth [n = 0].
The University of Iowa.
Copyright© 2005
24
A. Kruger
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
25
A. Kruger
Development Boards
• Atmel
– AT86RF210 Z-Link™ Transceiver is an 868/915
MHz direct sequence spread spectrum BPSK
transceiver designed for IEEE 802.15.4/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
802.15.4/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
26
A. Kruger
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
27
A. Kruger
Development Boards (cont.)
• Motorola/FreeScale 13192DSK
– Two 2.4 GHz wireless nodes
compatible with the IEEE 802.15.4
standard
• MC13192 2.4 GHz RF data modem
• MC9S08GT60 low-voltage, low-power 8-bit
MCU for baseband operations
• Integrated sensors
– MMA6261Q 1.5g X-Y-axis accelerometer
– MMA1260D 1.5g Z-axis accelerometer
• 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
28
A. Kruger
Development Boards (cont.)
• Emulator Development Kits
– Ember
– CompXs
– Helicomm
The University of Iowa.
Copyright© 2005
29
A. Kruger
Low Data Rate Wireless Evolution
First Stage
……… 2002
Second Stage
2003
2004
2005
2006
Third Stage
2007
2008
2009+
 Proprietary Dominates
 Proprietary Fades
 Standards Dominate
 IEEE 802.15.4 Emerges
 ZigBee Emerges
 IEEE 1451.5 Emerges
 System Integrator Focus
 Semiconductor Focus
 OEM Focus
 Leading Edge OEMs
 Early Adopter OEMs
 Wireless Ubiquitous
 $.1 - $1B Industry
 $1 - $10B Industry
 $10 - $100B+ Industry
 $1,000 - $100 Unit Cost
 $100 - $10 Unit Cost
 $10 - $1 Unit Cost
Mapping Your Future: From Data to Value
The University of Iowa.
Copyright© 2005
AMRA 2003 International
Symposium
30
A. Kruger
References
• The ZigBee Alliance web site
– http://www.zigbee.org
– Bob Heile, ZigBee Alliance Chairman [email protected]
•
•
•
•
•
Helicomm, Inc.
Atmel, Inc.
Microchip, Inc.
Motorola, Inc.
Thanks to Ryan Braun!
The University of Iowa.
Copyright© 2005
31
A. Kruger