Wireless Personal Area Networks based on Bluetooth, ZigBee, & Ultra-Wideband

1. Wireless Personal Area
Networks
CS5440 Wireless Access Networks
Dilum Bandara
Dilum.Bandara@uom.lk
Some slides extracted from ZigBee by J. Dohl, F. Diehm, & P. Grosa and
ZigBee by E. Ünal CSE 401 Special Topics In Computer Networks

2. Outline
 Bluetooth
 ZigBee
 Ultra-Wideband
2

3. 3
OSI
Stack
Source: http://walkwidnetwork.blogspot.com/2013/04/physical-layer-osi-model.html

4. OSI vs. TCP/IP
4
Source: http://blog.anuesystems.com/category/span-and-taps/

5. Bluetooth – IEEE 802.15.1
 Developed by Ericson
 Now managed by Bluetooth Special Interest Group
 2.4 – 2.48 GHz ISM band
 Range – 10 m
 Bandwidth – 2.1 Mbps (shared) (version 2.0)
 Version 4.0
 Includes Classic Bluetooth, Bluetooth high speed & Bluetooth low
energy protocols
 Bluetooth high-speed based on Wi-Fi
 Classic Bluetooth based on legacy Bluetooth protocols
 Low power consumption
 Found in mobile phones, laptops, computer peripherals,
printers, etc. 5

6. Bluetooth Applications
 Cable replacement
 Phone to PC connection
 Connecting computing devices
 Digital imaging
 Smart car systems
 Multiparty data exchange
 Exchange business cards, calendar events
 Share presentation material
 Synchronize information between multiple terminals
 Play multi-player games
 Personal trusted device
 Reliable e-commerce transactions
 Local value added services
 Locking & access control 6
Stick N Find

7. Bluetooth Piconet
 Through master
 No slave-to-slave communication
 Up to 7 active slaves 255 parked slaves 7
Source: www.techrepublic.com/article/secure-your-bluetooth-
wireless-networks-and-protect-your-data/6139987

8. Bluetooth Scatternet
 By connecting 2+
piconets
 No direct support at
Baseband Layer
8
Source: www.techrepublic.com/article/secure-your-bluetooth-
wireless-networks-and-protect-your-data/6139987

9. Bluetooth Protocol Stack
9
Source: http://withfriendship.com/user/sathvi/bluetooth-stack.php

10. Protocols & Usage Models
10
PPP
RFCOMM
TCP/IP
Baseband
L2CAP
OBEX
IrMC
TCS-BIN
Audio
Sync
Dial-up
net.
Usage Models
File
Transfer
AT-commands
Fax Headset
LAN
Access
Cordless
Phone
SDP
LMP

11. Bluetooth Protocol Stack (Cont.)
11

12. Bluetooth Applications/Profiles
 Set of application protocols
 Definitions of possible applications & specify general
behaviors
 Resides on top of Bluetooth core specification &
(optionally) additional protocols
 Example profiles
 Hands-Free Profile (HFP)
 Basic Printing Profile (BPP)
 Audio/Video Remote Control Profile (AVRCP)
 File Transfer Profile (FTP)
 Human Interface Device Profile (HID)
 Personal Area Networking Profile (PAN)
 Generic Object Exchange Profile (GOEP)
 OBEX
12

13. Other Key Layers
 Link Management Protocol (LMP)
 Set-up & control of radio link between 2 devices
 Logical Link Control & Adaptation Protocol (L2CAP)
 Multiplex multiple logical connections between 2 devices using
different higher-level protocols
 Provides segmentation & reassembly of on-air packets
 Service Discovery Protocol (SDP)
 Allows a device to discover services offered by other devices, &
their associated parameters
 Baseband layer
 Physical layer
 Manages physical channels & links
 Error correction, data whitening, hop selection, & security
13

14. Physical Channel
 Required to use spread spectrum technology as
it’s in ISM band
 79 RF channels spaced 1 MHz apart
 Channel – frequency range in which communication
occurs
 Frequency hoping
 Channel represented by a pseudo-random hopping
sequence hopping through 79 channels
 Piconet – all devices use same channel
 Hopping sequence is unique for the piconet & is determined
by device address (BD_ADDR) of master
14

15. Physical Channel (Cont.)
 Traffic controlled by master
 Master clock used for all timing & scheduling activities
 Master transmissions at even slots, slaves always at odd
slots
 Packet extended over up to 5 slots
15

16. Packets
 Access code
 Used for timing synchronization, offset compensation, paging &
inquiry
 Header
 Contains information for packet acknowledgement, packet
numbering for out-of-order packet reordering, flow control, slave
address, & error check for header
 Payload
 Can contain either voice field, data field, or both
16

17. ZigBee
 By ZigBee Alliance
 Very low power consumption  long battery life
 Low data rate
 Low complexity circuits & small size  low cost
17

18. ZigBee Applications
Telecom
Services
m-commerce
info services
object interaction
(Internet of Things)
ZigBee
Wireless Control that
Simply Works
TV
VCR
DVD/CD
remote
security
HVAC
lighting control
access control
irrigation
PC&
Peripherals
asset mgt
process
control
environmental
energy mgt
Personal
Health Care
security
HVAC
AMR
lighting control
access control
patient
monitoring
fitness
monitoring
18
Source: http://zigbee.org/

19. ZigBee Protocol Stack
 IEEE 802.15.4 covers
physical layer & MAC
layer of low-rate
WPAN
 ZigBee adds network
construction,
application services,
& more on top of
IEEE 802.15.4
19
Source: www.sena.com/products/industrial_zigbee/zigbee_summary.php

20. IEEE 802.15.4 Devıce Types
 LR-WPAN devices defined by IEEE 802.15.4
1. Full Functional Device (FFD)
 Can work as a PAN coordinator, as a coordinator, or
as a simple device
 Can communicate with either another FFD or a RFD
2. Reduced Functional Device (RFD)
 For applications that don’t need to transmit large
volumes of data & have to communicate only with a
specific FFD
20

21. IEEE/ZigBee Topologies
21
Source: http://wireless.arcada.fi/MOBWI/material/PAN_5_2.html

22. ZigBee Topologies (Cont.)
1. Star Topology
 Pros
 Easy to synchronize
 Low latency
 Cons
 Small scale
2. Mesh/P2P Topology
 Pros
 Robust multi-hop
communication
 Multi-path communication
 Flexible network
 Lower latency
 Cons
 Route discovery is costly
 Needs to store routing
table
22

23. ZigBee Topologies (Cont.)
3. Cluster Tree Topology
 Pros
 Low routing cost
 Multi-hop communication
 Scalable
 Cons
 Route reconstruction is costly
 Latency may be quite long
 Root node becomes a single point of failure
23

24. ZigBee Frequency Bands
24

25. PHY Protocol Data Unit (PPDU)
 2 different services
 Data service
 Controls radio
 Management service
 Energy detection in the channel
 Clear channel assesment before sending messages
 Link Quality Indication (LQI) for received packets
 Preamble for chip & symbol synchronization
 Frame size 8-127 Octets 25

26. MAC Layer
 2 services
 Data service
 Tx & Rx MPDUs
 Management service
 If coordinator
 Manages network beacons, PAN association & disassociation,
frame validation, & acknowledgment
 CSMA/CA for channel access
 Support device security
26

27. Traffic-Modes – Device to PAN
Coordinator
 Beacon mode
 Beacon send periodically
 Coordinator & end device
can go to sleep
 Lowest energy
consumption
 Precise timing needed
 Beacon period (ms-min)
27
Source: IEEE 802.15.4 Standard (2006)

28. Traffic-Modes – Device to PAN
Coordinator (Cont.)
 Non-Beacon mode
 Coordinator/routers have
to stay awake
 Heterogeneous network
 Asymmetric power
28
Source: IEEE 802.15.4 Standard (2006)

29. Data Transfer From PAN Coordınator
29
Source: IEEE 802.15.4 Standard (2006)

30. MAC Layer – Managing PANs
 Channel scanning
 Active, passive
 PAN ID conflict detection & resolution
 Starting a PAN
 Sending beacons
 Device discovery
 Device association/disassociation
 Synchronization (beacon/nonbeacon)
 Orphaned device realignment
30

31. MAC Layer – Frame Security
 Provided security features
 Access control
 Data encryption
 Frame integrity
 Sequential freshness
 Available security modes
 Unsecured mode
 ACL mode
 Secured mode
 Available security suites
 AES-CTR
 AES-CCM
 AES-CBC-MAC
31

32. Network Layer
 Distributed address assignment
 Tree structure or self managed by higher layer
 16-bit network space divided among child routers
 Child routers divide their space again for their children
 Depends on
 Maximum child count per parent
 Maximum child-routers per parent
 Maximum network depth
32

33. Network Layer (Cont.)
 Route discovery
 Find or update route between specific source &
destination
 Started if no active route present in routing table
 Broadcast routing request (RREQ) packets
 Generates routing table entries for hops to source
 Endpoint router responds with Routing response
(RREP) packet
 Routes generated for hops to destination
 Routing table entry generated in source device
33

34. Route Discovery
RREQ
RREP
1 2 3
4
2
1
5
34

35. Network Layer (Cont.)
 Routing
 Check if routing table entry exists
 Initiate route discovery if possible
 Hierarchical routing as fallback
 Route maintenance
 Track failed deliveries to neighbors
 Initiate route repair when threshold reached
 Careful with network load!
 In case of total connectivity loss
 Orphaning procedure
 Re-association with network
35

36. ZigBee Profiles
 Describes a common language for exchanging
data
 Defines offered services
 Device interoperability across different
manufacturers
 Standard profiles available from the ZigBee
Alliance
 Profiles contain device descriptions
 Unique identifier (licensed by the ZigBee Alliance)
36

37. ZigBee vs. Bluetooth
Feature(s) Bluetooth ZigBee
Power Profile days years
Complexity complex Simple
Nodes/Master 7 64000
Latency 10 seconds 30 ms – 1s
Range 10m 70m ~ 300m
Extendibility no Yes
Data Rate 1 Mbps 250 Kbps
Security 64bit, 128bit 128bit AES &
Application Layer 37

38. ZigBee vs. BluetoothSHORT<RANGE>LONG
LOW < DATA RATE > HIGH
PAN
LAN
Text Graphic
s
Internet Hi-fi
Audio
Streaming
Video
Digital
Video
Multi-channel
Video
802.15.1
Bluetooth1
802.15.1
Bluetooth 2
802.15.4
ZigBee
802.11b
802.11a/HL2 & 802.11g
38

39. Ultra-Wideband
 Short-range technology for high-speed WPANs
 3.1 – 10.6 GHz, 15 MHz channels (up to 5)
 10 m
 Applications – Cell phones, HDTV, DVD players, audio
players, etc.
39
Source: www.ice.rwth-aachen.de/index.php?id=630&tx_felogin_pi1[forgot]=1&tx_iceprojects_pi1[uid]=155

40. Ultra-Wideband (Cont.)
 Emit large no of very-short pluses over a wide
bandwidth
 Few nanoseconds or less
 Gains few 100s of Mbps
 Channel capacity proportional to used bandwidth
 No specific frequency allocation
 Operate on frequency band allocated to other
technologies
 Secure
 Like other spread spectrum technologies
40

41. Protocol Stack
 Wireless USB, Wireless IP, Bluetooth over UWB, &
IEEE1394 over UWB can be operated over a common
radio platform
41
Source: http://research.nokia.com/page/244

42. Summary
 Bluetooth
 Spread Spectrum
 Moderate rate, short-range (10 m)
 ZigBee
 Low rate, low power, short range (10 m – 100 m)
 Ultra-Wideband
 High rate, very-short range
42