Slide

Slide
Paper Reading Assignment IV
(Due on October 11th)
•
Duquennoy, Simon, Beshr Al Nahas, Olaf Landsiedel, and Thomas
Watteyne. "Orchestra: Robust mesh networks through autonomously
scheduled TSCH." In Proceedings of the 13th ACM Conference on
Embedded Networked Sensor Systems, pp. 337-350. ACM, 2015.
•
http://www.simonduquennoy.net/papers/duquennoy15orchestra.pdf
RF Wireless Data Rates & Ranges
Faster
Wireless Video
Applications
WAN
WLAN
UWB
Wireless Data
Applications
Peak Data Rate (Performance)
802.11g/n /AC
Medium Power
802.11a
Medium-Power (Low-
Wi-Fi®
802.11b
Cost)
Smart Converged
Gateway
4G
2.5G/3G
BT (LE)
Bluetooth™
NFC
Slower
(Medium Cost)
IrDA
Cellular
Sub-GHz Sensors
RFID
3G/4G BB
High-Power (High
Low Data-Rate
Transfer
Low-Power
ZigBee™ WSN
Wireless Sensor
Networking
(Long Battery Life
Low Cost)
Closer
WSN
(PAN)
Cost)
Low-Power (Long
Mesh Network
Range
Battery Life, Medium
Cost)
Farther
Networked Smart Gateway (MPC8308NSG)
Converged Architecture
Wireless media gateway
Home security & safety surveillance
Smart energy home automation
Health monitoring & management
Seamless Wireless Connectivity
(TCP/IP, 802.11n, ZigBee)
Smart metering connectivity via SE 1.0 or MBus
Smart appliance management via ZigBee HA1.0
Anytime/Anywhere access via internet connected devices
Integration of four essential software stacks
TCP/IP - Broadband WAN/LAN connectivity
ZigBee Home Automation 1.0 Profile
ZigBee Smart Energy 1.0 Profile
Web-based GUI (Java) for Ease of Use
Fully ready for Mass Production NOW
Freescale owned hardware & software
Solid hardware partnerships
Several ODMs are engaged
Traction with several consumer & utility OEMs
Branding, value and eCommerce enabling platform
IEEE 802.15.4
Content
•
•
•
•
•
•
•
•
Overview
Topologies
Superframe structure
Frame formatting
Data service
Management service
Interframe spacing
CSMA procedure
Slide 5
Introduction
• Until recently the main concentration In wireless was on high
throughput.
• Some applications for home automation, security, agriculture,
industrial etc. have relaxed throughput requirements with low
power consumption and low cost.
• Existing standards are not suitable because of high complexity,
power implications and high cost.
6
Applications
Home automation
heating, ventilation, and air conditioning, security, lighting, and
the control of objects.
Industrial
detecting emergency situations, monitoring machines
Automotive
automotive sensing, such as tire pressure monitoring;
Agriculture
sensing of soil moisture, pesticide, herbicide, and pH levels.
Others
Controlling consumer electronics, PC peripherals etc.
Data rate needed ranges from 115.2 kb/s to less than 10 kb/s.
7
IEEE 802.15 Working Group
8
Comparison between WPANs
9
802.15.4 Architecture
Upper Layers
IEEE 802.15.4 Service
Specific Convergence
Sub Layer (SSCS)
IEEE 802.2
LLC, Type I
IEEE 802.15.4 MAC
IEEE 802.15.4
868/915 MHz
PHY
IEEE 802.15.4
2400 MHz
PHY
10
Protocol Drivers
• Extremely low cost
• Ease of installation
• Reliable data transfer
• Short range operation
• Reasonable battery life
Slide 11
IEEE 802.15.4 Device Classes
• Full function device (FFD)
–
–
–
–
Any topology
PAN coordinator capable
Talks to any other device
Implements complete protocol set
• Reduced function device (RFD)
– Limited to star topology or end-device in a peer-to-peer
network.
– Cannot become a PAN coordinator
– Very simple implementation
– Reduced protocol set
Slide 12
IEEE 802.15.4 Definitions
• Network Device: An RFD or FFD implementation
containing an IEEE 802.15.4 medium access control
and physical interface to the wireless medium.
• Coordinator: An FFD with network device
functionality that provides coordination and other
services to the network.
• PAN Coordinator: A coordinator that is the principal
controller of the PAN. A network has exactly one
PAN coordinator.
Slide 13
Device Addressing
• Two or more devices communicating on the same
physical channel constitute a WPAN which includes at
least one FFD (PAN coordinator).
• Each independent PAN will select a unique PAN
identifier.
• All devices operating on a network shall have unique
64-bit extended address. This address can be used for
direct communication in the PAN.
• An associated device can use a 16-bit short address,
which is allocated by the PAN coordinator when the
device associates.
IEEE 802.15.4 Supported Topologies
• MAC supports 2 topologies: star and peer-to-peer
• Star topology supports beacon and no-beacon
structure
– All communication done through PAN coordinator
Star Topology
• Any FFD may establish its own network by becoming
the PAN coordinator
• After formation, star networks operate
independently from neighboring networks
• PAN coordinator starts sending beacons
– Other devices can associate with the network by sending
an association request
Peer-to-Peer Topology
• Any FFD can communicate with any other FFD
– i.e., this is ad-hoc networking
• RFDs can participate only as peripherals
– Do not have the capabilities of forwarding packets
• Each device responsible for proactively searching for
other devices
– Once a device is found, then they can exchange
information about what devices form the PAN
Technical Characteristics
• Physical layer
– 20 kbps over 1 channel @ 868-868.6 MHz
– 40 kbps over 10 channels @ 905 – 928 MHz
– 250 kbps over 16 channels @ 2.4 GHz
• MAC protocol
– Single channel at any one time
– Combines contention-based and schedule-based schemes
18
Physical Frequencies and Channels
868MHz / 915MHz
PHY
2.4 GHz
PHY
2.4 GHz
Channel 0
Channels 1-10
868.3 MHz
902 MHz
Channels 11-26
2 MHz
928 MHz
5 MHz
2.4835 GHz
19
IEEE 802.15.4 MAC overview
•
Star networks: devices are associated with coordinators
–
•
Coordinator
–
–
•
Forming a PAN, identified by a PAN identifier
Bookkeeping of devices, address assignment, generate beacons
Talks to devices and peer coordinators
Beacon-mode superframe structure
–
GTS assigned to devices upon request b
20
IEEE 802.15.4 MAC Overview
General Frame Structure
PHY Layer
MAC
Layer
Payload
Synch. Header
(SHR)
MAC Header
(MHR)
PHY Header
(PHR)
MAC Service Data Unit
(MSDU)
MAC Footer
(MFR)
MAC Protocol Data Unit (MPDU)
PHY Service Data Unit (PSDU)
4 Types of MAC Frames:
• Data Frame
• Beacon Frame
• Acknowledgment Frame
• MAC Command Frame
24
General MAC Frame Format
Octets:2
Frame
control
1
0/2
0/2/8
0/2
Destination
Source
Destination
Sequence
PAN
PAN
address
number
identifier
identifier
Addressing fields
0/2/8
Source
address
MAC header
Bits: 0-2
3
4
5
6
7-9
Frame type
Security
enabled
Frame
pending
Ack. Req.
Intra PAN
Reserved
variable
2
Frame
payload
Frame
check
sequence
MAC
payload
MAC footer
10-11
Dest.
addressing
mode
12-13
Reserved
14-15
Source
addressing
mode
Frame control field
Slide 25
Beacon Frame Format
Octets:2
1
4 or 10
2
variable
variable
Frame
control
Beacon
sequence
number
Source address
information
Superframe
specification
GTS
fields
Pending
address
fields
MAC header
Bits: 0-3
Beacon
order
4-7
8-11
Superframe Final CAP
order
slot
MAC payload
12
Battery life
extension
13
Reserved
variable
2
Beacon payload
Frame
check
sequence
MAC
footer
14
15
PAN
Association
coordinator
permit
Slide 26
MAC Command Frame
Octets:2
Frame
control
1
4 to 20
1
Data
Address Command
sequence
information
type
number
MAC header
variable
2
Command payload
Frame
check
sequence
MAC payload
MAC
footer
• Command Frame Types
–
–
–
–
–
Association request
Association response
Disassociation notification
Data request
PAN ID conflict notification
–
–
–
–
Orphan Notification
Beacon request
Coordinator realignment
GTS request
Slide 27
Data Frame Format
Octets:2
Frame
control
1
Data
sequence
number
4 to 20
variable
Address
information
Data payload
MAC header
MAC Payload
2
Frame
check
sequence
MAC
footer
Acknowledgement Frame Format
Octets:2
1
2
Data
Frame
Frame
sequence
check
control
number sequence
MAC
MAC header
footer
Slide 28
Data Service
• Data transfer to neighboring devices
– Acknowledged or unacknowledged
– Direct or indirect
– Using GTS service
• Maximum data length (MSDU) aMaxMACFrameSize
(102 bytes)
Slide 29
Direct Data Transfer
Message Sequence Diagram
Originator
higher layer
MCPS-DATA.request
Originator
MAC
Recipient
MAC
Recipient
higher layer
Data frame
Acknowledgment (if requested)
MCPS-DATA.indication
MCPS-DATA.confirm
Slide 30
Indirect Data Transfer
Message Sequence Diagram
Coordinator
higher layer
Coordinator
MAC
Device
MAC
Device
higher layer
MCPS-DATA.request
(indirect)
Beacon frame
Data request
Acknowledgement
Data frame
Acknowledgment
MCPS-DATA.indication
MCPS-DATA.confirm
Slide 31
Management Service
•
•
•
•
•
•
•
Access to the PIB
Association / disassociation
GTS allocation
Message pending
Node notification
Network scanning/start
Network synchronization/search
Passive Scan
Device
higher layer
Device
MAC
Coordinator
MAC
MLME-SCAN.request
st
Set 1 Channel
ScanDuration
Beacon
nd
Set 2 Channel
MLME-SCAN.confirm
Slide 33
Active Scan
Device
higher layer
Device
MAC
Coordinator
MAC
MLME-SCAN.request
st
Set 1 Channel
Beacon request
CSMA
ScanDuration
Beacon
nd
Set 2 Channel
Beacon request
MLME-SCAN.confirm
Slide 34
Association
Message Sequence Diagram
Device
higher layer
Device
MAC
MLME-ASSOCIATE.request
Coordinator
MAC
Coordinator
higher layer
Association request
Acknowledgment
MLME-ASSOCIATE.indication
aResponseWaitTime
MLME-ASSOCIATE.response
Data request
Acknowledgment
Association response
Acknowledgement
MLME-ASSOCIATE.confirm
MLME-COMM-STATUS.indication
In IEEE 802.15.4, association results are announced in an indirect fashion
Disassociation
Message Sequence Diagram
=
Originator
higher layer
Originator
MAC
Recipient
MAC
Recipient
higher layer
MLME-DISASSOCIATE.request
Disassociation notification
Acknowledgment
MLME-DISASSOCIATE.confirm
MLME-DISASSOCIATE.indication
Data Polling
Message Sequence Chart
Device
higher layer
Device
MAC
Coordinator
MAC
MLME-POLL.request
Data request
Acknowledgment (FP = 0)
MLME-POLL.confirm
No data pending at the coordinator
Data Polling
Message Sequence Chart
Device
higher layer
Device
MAC
Coordinator
MAC
MLME-POLL.request
Data request
Acknowledgment (FP = 1)
Data
Acknowledgement
MLME-POLL.confirm
MCPS-DATA.indication
Data pending at the coordinator
Channel Access Mechanism
In non beacon-enabled networks
- unslotted CSMA/CA channel access mechanism
In beacon-enabled networks
- slotted CSMA/CA channel access mechanism
Based on a basic time unit called Backoff Period
(BP)
= aUnitBackoffPeriod = 80 bits (0.32 ms)
Un-slotted CSMA Procedure
Un-slotted CSMA
NB = 0,
BE = macMinBE
Delay for
random(2BE - 1) unit
backoff periods
Perform CCA
Used in non-beacon
networks.
Y
Channel idle?
N
NB = NB+1,
BE = min(BE+1, aMaxBE)
N
NB>
macMaxCSMABackoffs
?
Y
Failure
Success
Slide 41
Slotted CSMA Procedure
Slotted CSMA
Delay for
random(2BE - 1) unit
backoff periods
NB = 0, CW = 0
Battery life
extension?
Y
Perform CCA on
backoff period
boundary
BE = lesser of
(2, macMinBE)
N
Y
BE = macMinBE
Channel idle?
N
Locate backoff
period boundary
N
Used in beacon enabled networks.
CW = 2, NB = NB+1,
BE = min(BE+1, aMaxBE)
CW = CW - 1
NB>
macMaxCSMABackoffs
?
CW = 0?
Y
Failure
N
Y
Success
Slide 42
802.15.4 Architecture
Applications
ZigBee
IEEE 802.15.4 MAC
IEEE 802.15.4
868/915 MHz
PHY
IEEE 802.15.4
2400 MHz
PHY
43
ZigBee
• Pushed by Chipcon (now TI), ember, freescale (Motorola),
Honeywell, Mitsubishi, Motorola, Philips, Samsung…
• More than 260 members
– about 15 promoters, 133 participants, 111 adopters
– must be member to commercially use ZigBee spec
• ZigBee platforms comprise
– IEEE 802.15.4 for layers 1 and 2
– ZigBee protocol stack up to the applications
44
ZigBee Stack Architecture
45
Typical ZigBee-Enabled Device Design
Typical design consist of RF IC and 8-bit
microprocessor with peripherals connected to an
application sensor or actuators
46
Competing/Similar Technologies
• Bluetooth
– http://www.bluetooth.org
– http://www.bluetooth.com
• X10
– Powerline protocol first introduced in the 1970's.
– http://www.x10.com/technology1.htm
• Z-wave
– Proprietary protocol for wireless home control networking.
– http://www.z-wavealliance.com/
• INSTEON
– Peer-to-peer mesh networking product that features a hybrid
radio/powerline transmission
– http://www.insteon.net
• nanoNET
– Proprietary set of wireless sensor protocols, designed to compete with
ZigBee.
– http://www.nanotron.com/
47
Summary
•
802.15.4: Low-Rate, Very Low-Power
– Low data rate solution with multi-month to multi-year battery life and very low
complexity
– Potential applications are sensors, interactive toys, smart badges, remote controls,
and home automation
– Data rates of 20-250 kbit/s, latency down to 15 ms
– Master-Slave or Peer-to-Peer operation
– Up to 254 devices or 64516 simpler nodes
– Support for critical latency devices, such as joysticks
– CSMA/CA channel access (data centric), slotted (beacon) or unslotted
– Automatic network establishment by the PAN coordinator
– Dynamic device addressing, flexible addressing format
– Fully handshaked protocol for transfer reliability
– Power management to ensure low power consumption
– 16 channels in the 2.4 GHz ISM band, 10 channels in the 915 MHz US ISM band and
one channel in the European 868 MHz band
– Basis of the ZigBee technology – www.zigbee.org
48
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