Wireless Technologies for Automation

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Lehrgebiet Softwaretechnik und Rechnernetze (C) Prof. Dr.-Ing. Jörg F. Wollert

Prof. Dr.-Ing. Jörg F. Wollert

Wireless Technologies for

Automation

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Wireless Technologies for Automation

Why using wireless communication?

Pros and cons in wireless networks

Embedded Wireless

Hardware

Software

A short technology overview

WLAN

Bluetooth

ZigBee

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Lehrgebiet Softwaretechnik und Rechnernetze

Why using wireless communication?



Use-cases for wireless technology



Cable Replacement: cheap and easy

interface with high data rate



Ad-hoc Networks: security and

flexible network configuration



Mobile Solutions: security, low

power and high reliability



Embedded: cheap, small, available



In all:

 Standardized communication  precisely defined protocols

 Scalable communication profiles for

data, speach and media content



Some demands



Suitable security with authentication

and authorization



Mobile services for control, diagnostic

and visualization



Integration of mobile Consumer

devices like mobile phone, PDA or

laptop

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Pros and cons of wireless networks

Pros:



Easy integration of mobile, distributed communication systems



Independent usage of electronic devices



No problems in cabling



Unsusceptible against disaster and careless users



Easy access without infrastructure

Cons:



Less data rate in comparison with standard Ethernet cabling



Difficult administration for a suitable security



Great differences in standards and interoperability



A lot of regulation constrains

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

worldwide common technology



No licenses and worldwide use without fee



Interoperability between products of different manufacturer



Robust and reliable transmission of data



Easy to use and simple configuration



Interoperability with cable based systems



Insensitive against various security attacks

(Interruption, Interception, Modification, Fabrication)



Low power consumption



Large communication range



Large number of active stations

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900 MHz & 2.4 GHz global admission

2,4 GHz global admission

Available ISM Frequencies

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Classification of wireless technology

Wireless Communication

distance > 100 m

distance > 100 m distance < 100 m_{distance < 100 m} distance < 10 m_{distance < 10 m} distance > 1000 m distance > 1000 m > 100 kbps > 100 kbps < 10 kbps_{< 10 kbps} > 100 kbps_{> 100 kbps} < 10 kbps_{< 10 kbps} > 100 kbps_{> 100 kbps} < 10 kbps_{< 10 kbps} > 100 kbps_{> 100 kbps} < 10 kbps_{< 10 kbps} Internet Information Diagnosis Update Switching Supervision Control GSM GSM/GPRS UMTS HotSpot WLAN 433 MHz 868 MHz HotSpot WLAN Bluetooth 433 MHz 868 MHz ZigBee Bluetooth Diagnosis Service Update Mobilephone-Integration Computer-Periphery Multimedia WLAN Bluetooth Switching Supervision Control Human-Control-Interface Computer-Periphery 433 MHz 868 MHz ZigBee Bluetooth Internet Information Diagnosis Update Switching Supervision Control Internet Information Diagnosis Update Switching Supervision Control

WAN Wide Area Network

WAN Wide Area Network LAN Local Area Network_{LAN Local Area Network} PAN Personal Area Network_{PAN Personal Area Network}

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Embedded

Wireless

Why using wireless communication?

Pros and cons in wireless networks

Embedded Wireless

Hardware

Software

A short technology overview

WLAN

Bluetooth

ZigBee

Conclusion

(9)

Software and hardware in embedded systems

Requirements



Hardware



Standardized functionality

 802.11 a,b,…;Bluetooth,ZigBee



Standardized interfaces

 SPI, USB, UART, PCCard



Software



Operating System

 Protocol Stacks  IP,TCP,UDP,OBEX,…  Defined functionality  DHCP,SMTP,ICMP,… 

Application

 Defined interfaces  Application profiles  Interoperability tests 

Question



Which functionality is done by the

wireless controller?



How much memory is used by the

necessary protocol stacks?



How much computing power is

consumed for handling the wireless

connections?

Application Application Transport Transport Network Network Link control Link control Physical Physical 1 2 3 4 7 ISO/OSI-Communication

Model Hardware Software

Link Manager Firmware Link Manager Firmware Operating System Operating System TCP / UDP TCP / UDP IP IP Application Application Hostcomputer Wireless Device

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Embedded

Wireless

Why using wireless communication?

Pros and cons in wireless networks

Embedded Wireless

Hardware

Software

A short technology overview 2.4 GHz

WLAN

Bluetooth

ZigBee

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Lehrgebiet Softwaretechnik und Rechnernetze O S O S A pp . A pp .

Wireless LAN 802.11



Normally WLAN is used to replace a

wired Ethernet connection.



Beside a hardware driver for the

special WLAN-hardware the additional

IP, UDP and TCP-protocol stack is

necessary.



TCP/IP-Stack is expensive and needs

a lot of memory and computing power



A lot of different incompatible or

additional specifications are available



802.11 is build for asynchronous

communication with a high data rate

typically 11 Mbps (802.11b), 54 Mbps

(802.11g) up to 100 Mbps



Special Profiles are not defined



Interoperability is guaranteed by the

WiFi logo

PHY and MAC PHY and MAC Hardware Driver Hardware Driver IP Internet

IP InternetProtocolProtocol

TCP

TCP UDPUDP

HTTP

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Bluetooth



Bluetooth features

 2.4 GHz ISM-Band, 79 Kanäle, 1 Mbps  GFSK, FHSS 1600 Hops/sec

 Connection oriented Link (SCO) for

voice-applications

 Asynchronous connectionless link (ACL) for

dataservices

 Master-slave piconet with 7 active and up to

255 slaves in parked mode



Completely defined, scalable software

 25 different communication profiles

 Network oriented profiles  Telephony, ISDN, fax profiles

 Various data-interchange profiles, based

on OBEX

 Human Interface definition profile  Cable replacement

 Service Discovery Profile and Application  Compatible with various products

Baseband Baseband A ud io A ud io HCI

HCI _{Link Manager}_{Link Manager}

L L22_CAP_CAP SDP SDP RFCOMMRFCOMM Pr ofi le s Pr ofi le s OBEX OBEX vC ard vC

ard vCalvCal vNotevNote

PPP PPP Bluetooth Core Protocols Bluetooth Host Protocols IT-Protocols BNEP BNEP IP IP UDP UDP TCPTCP ... ... HTTPHTTP SMTPSMTP OBEXOBEX RFCOMM

RFCOMM TCS binTCS bin AT

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Bluetooth

-

_-

Embedded

_Embedded

RF RF Baseband Baseband Link Manager Link Manager L L22_CAP_CAP SDP SDP Serial Serial Port Port Profile Profile RFCOMM RFCOMM AT AT--Bef.Bef. COM

COM SetupSetup

Sc he du le r Sc he du le r Connect

Connect/Security/SecurityManagerManager Application

Application



Various Bluetooth-chips have

programmable build-in µC

 Host controller is not necessary  Different profiles and

applications may be build in the chipset



Embedded devices

 Application runs on the

BT-module

 Build in security and connection

manager take care of highest possible security

 Connected serial devices

doesn't need any further software implementations

 No software protocols are

necessary on the host controller .

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ZigBee



ZigBee features



Data rate 20, 30 and 250 kbps



Low power consumption, low price



Scalable range and data rate in 868/915

MHz and 2.4 GHz



Star and mashed net topology

 FFD network coordinator  RFD tiny network client



Up to 254 RFD are managed by one FFD



Routing capability between FFD



Small protocol stacks and few resources



PHY and MAC layer are defined in IEEE

802.15.4 specification



The ZigBee stack is in specification

Zig B ee A llia nc e IE EE 80 2.1 5.4 Security Security Service Service Provider Provider (SSP) (SSP) 802.15.4 PHY

802.15.4 PHY --LayerLayer 802.15.4 Medium Access

802.15.4 Medium Access

Netzwerk

Netzwerk Layer (NWK)Layer (NWK)

Application Layer (APL)

Application Support Sub

Application Support Sub--Layer (APS)Layer (APS)

ZigBee

ZigBeeDevice Objects (ZDO)Device Objects (ZDO)

Sil ic on Zig B ee Sta ck

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On a glance: characteristics

L o w P o w e r S h o rt R a n g e H ig h P o w e r L o n g R a n g e ZigBee™ ZigBee™ Bluetooth™ Bluetooth™ 802.11b 802.11b 802.11a 802.11a 802.11g 802.11g UWB UWB

Low Data Rate High Data Rate

GSM

GSM GPRS/2½G_GPRS/2½G UMTS/3G_UMTS/3G

Text Graphics Internet Audio Video Multi-channel

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On a glance: Resource consumption

Reliability, Power, Cost Cost, Convenience Speed, Flexibility Reach, Quality Success Metrics 1 - 100+ 1 - 100 1 - 300 1,000+ Transmission Range (meters) 20 - 250 720 800 .. 54.000 64 - 128+ Bandwidth (KB/s) 255 / 65,000 7 –(250) 32 1 Network Size 100 - 1,000+ 1 - 7 .5 - 5 1-7

Battery Life (days)

4KB - 32KB 250KB+ 1MB+ 16MB+ System Resources Monitoring & Control Audio, Cable Replacement Web, Email, Video Wide Area

Voice & Data Application Focus ZigBee™ 802.15.4 Bluetooth™ 802.15.1 Wi-Fi™ 802.11b,g GPRS/GSM 1xRTT/CDMA Market Name Standard

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Embedded Wireless

Why using wireless communication?

Pros and cons in wireless networks

Embedded Wireless

Hardware

Software

A short technology overview 2.4 GHz

WLAN

Bluetooth

ZigBee

Conclusion

(18)

Conclusion



Wireless products are trendy



Different technologies are available



The used technology depends on the

specific requirements

 Power consumption  Data rate and topologies

 Interoperability to consumer or network

products

 Security and reliability

 Easy engineering and less complexity

433 und 868 MHz, ZigBee

 Low end products with less demands on

security, only small data rate, high range, few resources and specialized protocol stacks.

Bluetooth

 Tiny products with interoperability up to 25

different profiles

 Different channels for audio and data

 Highest embedded security on chipset level  Easy scalable systems with build-in

processors

 Exactly defined and tested interoperability  Compatibility to consumer products

WLAN 802.11

 Compatibility to Ethernet

 Very high data rate, large range

Application Application Transport Transport Network Network Link control Link control Physical Physical 1 2 3 4 7 Link Manager Link Manager Firmware Operating System Operating System TCP / UDP TCP / UDP IP IP Application Application Hostcomputer Wireless Device

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