Zainab Zaidi

1
ELEC 5508 Wireless NetworksPart 2 Data
services

• Zainab Zaidi
• Network Systems Group
• NICTA
• Zainab.Zaidi_at_nicta.com.au
• Consultation Time Wednesday 4-6 pm
• Lab 730 EE

2
Contents

• IEEE 802.15 Wireless Personal Area Networks
  (WPANs)
• Bluetooth IEEE 802.15.1
• Ultra-wideband (UWB) IEEE 802.15.3a
• Zigbees IEEE 802.15.4
• Radio Frequency Identification (RFID)

3
Bluetooth

• Idea
• Universal radio interface for ad-hoc wireless
  connectivity
• Interconnecting computer and peripherals,
  handheld devices, PDAs, cell phones replacement
  of IrDA
• Embedded in other devices, goal 5/device (2005
  40/USB bluetooth)
• Short range (10 m), low power consumption,
  license-free 2.45 GHz ISM
• Voice and data transmission, approx. 1 Mbit/s
  gross data rate

One of the first modules (Ericsson).
4
Characteristics

• 2.4 GHz ISM band, 79 RF channels, 1 MHz carrier
  spacing
• Channel 0 2402 MHz channel 78 2480 MHz
• G-FSK modulation, 1-100 mW transmit power
• FHSS and TDD
• Frequency hopping with 1600 hops/s
• Hopping sequence in a pseudo random fashion,
  determined by a master
• Time division duplex for send/receive separation
• Voice link SCO (Synchronous Connection
  Oriented)
• FEC (forward error correction), no
  retransmission, 64 kbit/s duplex, point-to-point,
  circuit switched
• Data link ACL (Asynchronous ConnectionLess)
• Asynchronous, fast acknowledge,
  point-to-multipoint, up to 433.9 kbit/s symmetric
  or 723.2/57.6 kbit/s asymmetric, packet switched
• Topology
• Overlapping piconets (stars) forming a scatternet

5
Piconet

• Collection of devices connected in an ad hoc
  fashion
• One unit acts as master and the others as slaves
  for the lifetime of the piconet
• Master determines hopping pattern, slaves have to
  synchronize
• Each piconet has a unique hopping pattern
• Participation in a piconet synchronization to
  hopping sequence
• Each piconet has one master and up to 7
  simultaneous slaves (gt 200 could be parked)

P
S
S
M
P
SB
S
P
SB
PParked SBStandby
MMaster SSlave
6
Forming a piconet

• All devices in a piconet hop together
• Master gives slaves its clock and device ID
• Hopping pattern determined by device ID (48 bit,
  unique worldwide)
• Phase in hopping pattern determined by clock
• Addressing
• Active Member Address (AMA, 3 bit)
• Parked Member Address (PMA, 8 bit)

?
?
P
?
S
?
SB
?
SB
S
?
?
?
SB
M
P
?
?
SB
SB
?
?
SB
?
S
?
?
?
SB
SB
P
?
SB
?
SB
SB
7
Scatternet

• Linking of multiple co-located piconets through
  the sharing of common master or slave devices
• Devices can be slave in one piconet and master of
  another
• Communication between piconets
• Devices jumping back and forth between the
  piconets

Piconets (each with a capacity of 720 kbit/s)
P
S
S
S
P
P
M
M
SB
S
MMaster SSlave PParked SBStandby
P
SB
SB
S
8
Bluetooth protocol stack
vCal/vCard
NW apps.
telephony apps.
audio apps.
mgmnt. apps.
Host Controller Interface
Link Manager
Baseband
Radio
AT attention sequence OBEX object exchange TCS
BIN telephony control protocol specification
binary BNEP Bluetooth network encapsulation
protocol
SDP service discovery protocol RFCOMM radio
frequency comm.
9
Frequency selection during data transmission
625 µs
fk
fk1
fk2
fk3
fk4
fk5
fk6
S
M
M
M
M
S
S
t
fk3
fk4
fk
fk5
fk6
M
M
M
S
S
t
fk
fk1
fk6
M
M
S
t
10
Baseband

• Piconet/channel definition
• Low-level packet definition
• Access code
• Channel, device access, e.g., derived from master
• Packet header
• 1/3-FEC, active member address (broadcast 7
  slaves), link type, alternating bit ARQ/SEQ,
  checksum

68(72)
54
0-2745
bits
access code
packet header
payload
4
64
(4)
3
4
1
1
1
8
bits
AM address
type
flow
ARQN
SEQN
HEC
preamble
sync.
(trailer)
11
Baseband data rates
Payload User Symmetric Asymmetric Header Paylo
ad max. Rate max. Rate kbit/s Type byte by
te FEC CRC kbit/s Forward Reverse DM1 1 0-17 2
/3 yes 108.8 108.8 108.8 DH1 1 0-27 no yes 172.8
172.8 172.8 DM3 2 0-121 2/3 yes 258.1 387.2 54.4
DH3 2 0-183 no yes 390.4 585.6 86.4 DM5 2 0-224
2/3 yes 286.7 477.8 36.3 DH5 2 0-339 no yes 433.9
723.2 57.6 AUX1 1 0-29 no no 185.6 185.6 185.6 HV
1 na 10 1/3 no 64.0 HV2 na 20 2/3 no 64.0 HV3 na
30 no no 64.0 DV 1 D 10(0-9) D 2/3 D yes
D 64.057.6 D
ACL
1 slot
3 slot
5 slot
SCO
Data Medium/High rate, High-quality Voice, Data
and Voice
12
SCO payload types
payload (30)
audio (10)
HV1
FEC (20)
HV2
audio (20)
FEC (10)
audio (30)
HV3
audio (10)
DV
header (1)
payload (0-9)
2/3 FEC
CRC (2)
(bytes)
13
ACL Payload types
payload (0-343)
header (1/2)
payload (0-339)
CRC (2)
header (1)
payload (0-17)
2/3 FEC
DM1
CRC (2)
header (1)
payload (0-27)
DH1
CRC (2)
(bytes)
header (2)
payload (0-121)
2/3 FEC
DM3
CRC (2)
header (2)
payload (0-183)
DH3
CRC (2)
header (2)
payload (0-224)
2/3 FEC
DM5
CRC (2)
header (2)
payload (0-339)
DH5
CRC (2)
header (1)
payload (0-29)
AUX1
14
Baseband link types

• Polling-based TDD packet transmission
• 625µs slots, master polls slaves
• SCO (Synchronous Connection Oriented) Voice
• Periodic single slot packet assignment, 64 kbit/s
  full-duplex, point-to-point
• ACL (Asynchronous ConnectionLess) Data
• Variable packet size (1,3,5 slots), asymmetric
  bandwidth, point-to-multipoint

SCO
SCO
SCO
SCO
ACL
ACL
ACL
ACL
MASTER
f6
f0
f12
f18
f8
f14
f4
f20
SLAVE 1
f1
f7
f13
f19
f9
SLAVE 2
f17
f5
f21
15
Robustness

• Slow frequency hopping with hopping patterns
  determined by a master
• Protection from interference on certain
  frequencies
• Separation from other piconets (FH-CDMA)
• Retransmission
• ACL only, very fast
• Forward Error Correction
• SCO and ACL

Error in payload (not header!)
NAK
ACK
A
C
C
H
F
MASTER
SLAVE 1
B
D
E
SLAVE 2
G
G
16
L2CAP - Logical Link Control and Adaptation
Protocol

• Simple data link protocol on top of baseband
• Connection oriented, connectionless, and
  signaling channels
• Protocol multiplexing
• RFCOMM, SDP, telephony control
• Segmentation reassembly
• Up to 64kbyte user data, 16 bit CRC used from
  baseband
• QoS flow specification per channel
• Follows RFC 1363, specifies delay, jitter,
  bursts, bandwidth
• Group abstraction
• Create/close group, add/remove member

17
L2CAP logical channels
Slave
Master
Slave
L2CAP
L2CAP
L2CAP
2
d
1
d
d
1
1
d
2
1
d
d
d
baseband
baseband
baseband
ACL
signalling
connectionless
connection-oriented
18
L2CAP packet formats
Connectionless PDU
?2
2
bytes
2
0-65533
length
CID2
PSM
payload
Connection-oriented PDU
2
bytes
2
0-65535
length
CID
payload
Signalling command PDU
2
bytes
2
length
CID1
One or more commands
1
1
2
?0
code
ID
length
data
19
Security
User input (initialization)
PIN (1-16 byte)
PIN (1-16 byte)
Pairing
Authentication key generation (possibly permanent
storage)
E2
E2
Authentication
link key (128 bit)
link key (128 bit)
Encryption key generation (temporary storage)
E3
E3
Encryption
encryption key (128 bit)
encryption key (128 bit)
Keystream generator
Keystream generator
Ciphering
payload key
payload key
Cipher data
Data
Data
20
802.11 vs. 802.15/Bluetooth

• Bluetooth may act like a rogue member of the
  802.11 network
• Does not know anything about gaps, inter frame
  spacing etc.
• IEEE 802.15-2 discusses these problems
• Proposal Adaptive Frequency Hopping
• a non-collaborative Coexistence Mechanism
• Real effects? Many different opinions,
  publications, tests, formulae,
• Results from complete breakdown to almost no
  effect
• Bluetooth (FHSS) seems more robust than 802.11b
  (DSSS)

21
WPAN IEEE 802.15-1 Bluetooth

• Data rate
• Synchronous, connection-oriented 64 kbit/s
• Asynchronous, connectionless
• 433.9 kbit/s symmetric
• 723.2 / 57.6 kbit/s asymmetric
• Transmission range
• POS (Personal Operating Space) up to 10 m
• with special transceivers up to 100 m
• Frequency
• Free 2.4 GHz ISM-band
• Security
• Challenge/response (SAFER), hopping sequence
• Availability
• Integrated into many products, several vendors

• Connection set-up time
• Depends on power-mode
• Max. 2.56s, avg. 0.64s
• Quality of Service
• Guarantees, ARQ/FEC
• Manageability
• Public/private keys needed, key management not
  specified, simple system integration
• Special Advantages/Disadvantages
• Advantage already integrated into several
  products, available worldwide, free ISM-band,
  several vendors, simple system, simple ad-hoc
  networking, peer to peer, scatternets
• Disadvantage interference on ISM-band, limited
  range, max. 8 devices/networkmaster, high set-up
  latency

22
WPAN IEEE 802.15

• 802.15-2 Coexistance
• Coexistence of Wireless Personal Area Networks
  (802.15) and Wireless Local Area Networks
  (802.11), quantify the mutual interference
• 802.15-3 High-Rate
• Standard for high-rate (20Mbit/s or greater)
  WPANs, while still low-power/low-cost
• Data Rates 11, 22, 33, 44, 55 Mbit/s
• Quality of Service isochronous protocol
• Ad hoc peer-to-peer networking
• Security
• Low power consumption
• Low cost
• Designed to meet the demanding requirements of
  portable consumer imaging and multimedia
  applications

23
UWB IEEE 802.15.3

• 802.15.3a
• Alternative PHY with higher data rate as
  extension to 802.15.3
• Applications multimedia, picture transmission
• 802.15.3b
• Enhanced interoperability of MAC
• Correction of errors and ambiguities in the
  standard
• 802.15.3c
• Alternative PHY at 57-64 GHz
• Goal data rates above 2 Gbit/s
• Not all these working groups really create a
  standard, not all standards will be found in
  products later

24
UWB in the Digital Home
Local high throughput delivery
Wired /Wireless
Wired / Wireless
Broadband
Wired / Wireless
Long range delivery wired wireless (Backbone)
Wired / Wireless
Wired / Wireless
UWB defines high spatial capacity and effortless
interconnectivity
Courtesyhttp//download.microsoft.com/download/9/
8/f/98f3fe47-dfc3-4e74-92a3-088782200fe7/TWMO05003
_WinHEC05.ppt
25
Qualities of the 802.15.3 MAC

• Centralized and connection-oriented ad-hoc
  networking topology
• The coordinator (PNC) maintains network
  synchronization timing, performs admission
  control, assigns time for connection between
  802.15.3 devices (DEV), manages PS requests,
• Communication is peer to peer
• Support for multimedia QoS
• TDMA superframe architecture with Guaranteed Time
  Slots (GTS)
• Authentication, encryption and integrity
• Multiple power saving modes (asynchronous and
  synchronous)
• Robustness
• Dynamic channel selection, TX power control per
  link
• PNC handover

Courtesy http//www.fcc.gov/realaudio/presentatio
ns/2002/042602/IEEE_802-15.ppt
26
Scalable Security Capabilities

• Mode 0 is no security
• Mode 1 allows the user to restrict access to the
  piconet
• User externally specifies which devices (MAC
  address) are in ACL
• Can be done with simple open enrollment modes
  using common button push
• Mode 2 provides cryptographic authentication,
  payload protection and command integrity.
• Mode 3 provides payload protection, command and
  data integrity as well as cryptographic
  authentication using digital certificates.
• The security modes above mode 0 are optional

Courtesy http//www.fcc.gov/realaudio/presentatio
ns/2002/042602/IEEE_802-15.ppt
27
Superframe Structure

• Time-slotted superframe structure consists of 3
  sections
• Beacon
• transmits control information to the entire
  piconet, allocates resources (GTS) per stream ID
  for the current superframe and provides time
  synchronization
• Optional CAP (CSMA/CA)
• used for authentication/association
  request/response, stream parameters negotiation,
  (command frames)
• PNC can replace the CAP with MTS slots using
  slotted Aloha access
• CFP made of
• Unidirectional Guaranteed Time Slots (GTS)
  assigned by the PNC for isochronous or
  asynchronous data streams
• Optional Management Time Slots (MTS) in lieu of
  the CAP for command frames

Courtesy http//www.fcc.gov/realaudio/presentatio
ns/2002/042602/IEEE_802-15.ppt
28
GTS and MTS Slots

• GTSs may have different persistence
• Dynamic GTS position in superframe may change
  from superframe to superframe (Beacon CTA IE or
  broadcast channel time Grant command)
• Pseudo-static GTS (isochronous streams) PNC may
  change the GTS positions, but needs to
  communicate and confirm with both Tx and Rx DEVs
• Variable guard times between adjacent slots to
  prevent collision (clock drift)
• MTS
• Open dedicated MTS Used for PNC/DEV
  communication
• Association MTS
• Number of MTS per superframe is controlled by the
  PNC

Courtesy http//www.fcc.gov/realaudio/presentatio
ns/2002/042602/IEEE_802-15.ppt
29
Quality of Service (QoS)

• QoS typically defined as the latency required to
  bound jitter of a continuous data stream at a
  desired rate.
• Latency can be used to buffer data stream so that
  effects of non-deterministic transmission times
  can be reduced.
• Very small amounts of jitter can be handled by
  the presentation device.
• Use of latency to reduce jitter requires higher
  channel bit rates to catch up.
• Additional requirements placed on systems where
  multiple data streams must be synchronized.
• Home theater audio distribution to multiple
  speakers
• Allocation of channel time (TDMA) the best
  solution.

Courtesy http//www.fcc.gov/realaudio/presentatio
ns/2002/042602/IEEE_802-15.ppt
30
2.4GHz PHY (802.15.3)

• 5 selectable data rates
• 11, 22, 33, 44, 55 Mb/s
• 11 Msymbol/s
• Modulation formats BPSK, QPSK (no coding), 16,
  32, 64-QAM (8-state Trellis code)
• 15 MHz channel bandwidth
• 3 or 4 non-overlapping channels
• 3 channel mode aligns with 802.11b for
  coexistence
• Transmit Power approximately 8 dBm
• Coexistence
• Compared to 802.11, an 802.15.3 2.4GHz PHY system
  causes less interference since it occupies a
  smaller bandwidth and transmits at lower power
  levels
• Provides for dynamic channel selection
• Per link dynamic power control
• Detects and monitors for active channels and moves

Courtesy http//www.fcc.gov/realaudio/presentatio
ns/2002/042602/IEEE_802-15.ppt
31
Alternate PHY Study Group (802.15.3a)

• 802.15.3 has created a Study Group to investigate
  the creation of an alternate PHY to address very
  high data rate applications
• Goal of gt 110Mbps _at_ 10 m, gt 400 Mbps _at_ 5 m
• 1394a, USB2.0 HS cable replacement
• DV50, DV100, HD DVD, High resolution printer and
  scanner, fast download speed for MP3 players,
  digital still cameras
• Currently reviewing Application Presentations and
  developing requirements documents
• UWB is a potential candidate for these VHR WPAN
  applications

Courtesy http//www.fcc.gov/realaudio/presentatio
ns/2002/042602/IEEE_802-15.ppt
32
UWB Throughput
Courtesyhttp//download.microsoft.com/download/9/
8/f/98f3fe47-dfc3-4e74-92a3-088782200fe7/TWMO05003
_WinHEC05.ppt
33
UWB Signals

• UWB signals are typically modulated pulse trains
• Very short pulse duration (lt1 ns)
• Uniform or non-uniform inter-pulse spacing
• Pulse repetition frequency (PRF) can range from
  hundreds of thousands to billions of
  pulses/second
• Modulation techniques include pulse-position
  modulation, binary phase-shift keying and others

Courtesy http//www.fcc.gov/realaudio/presentatio
ns/2002/042602/IEEE_802-15.ppt
34
What is Ultra Wideband?

• Radio technology that modulates impulse based
  waveforms instead of continuous carrier waves

Courtesyhttp//www.cse.ohio-state.edu/siefast/pre
sentations/ultra-wide-band-kimyoung-2003/ultra-wid
e-band-kimyoung-2003.ppt
35
Information Modulation
Pulse length 200ps Energy concentrated in
2-6GHz band Voltage swing 100mV Power 10uW

• Pulse Position Modulation (PPM)
• Pulse Amplitude Modulation (PAM)
• On-Off Keying (OOK)
• Bi-Phase Modulation (BPSK)

Courtesyhttp//www.cse.ohio-state.edu/siefast/pre
sentations/ultra-wide-band-kimyoung-2003/ultra-wid
e-band-kimyoung-2003.ppt
36
Large Relative (and Absolute) Bandwidth
Narrowband (30kHz)
Wideband CDMA (5 MHz)
Part 15 Limit
UWB (Several GHz)
Frequency

• UWB is a form of extremely wide spread spectrum
  where RF energy is spread over gigahertz of
  spectrum
• Wider than any narrowband system by orders of
  magnitude
• Power seen by a narrowband system is a fraction
  of the total
• UWB signals can be designed to look like
  imperceptible random noise to conventional radios

Courtesy http//www.fcc.gov/realaudio/presentatio
ns/2002/042602/IEEE_802-15.ppt
37
Large Fractional Bandwidth

• Original FCC UWB definition (NPRM) is 25 or more
  fractional bandwidth
• Fractional Bandwidth is the ratio of signal
  bandwidth (10 dB) to center frequency Bf B /
  FC 2(Fh-Fl) / (FhFl)
• Preliminary FCC rules enable in excess of 100
  fractional bandwidths
• 7.5 GHz maximum bandwidth at 10 dB points
• Large fractional bandwidth leads to
• High processing gain
• Multipath resolution and low signal fading

Courtesy http//www.fcc.gov/realaudio/presentatio
ns/2002/042602/IEEE_802-15.ppt
38
Multipath Performance

• Ultra-wide bandwidth provides robust performance
  in multipath environments
• Less severe signal fading due to multipath
  propagation means fade margin of only a few dB
• Extremely short pulses enable resolution and
  constructive use of multipath energy using RAKE
  receiver techniques

Courtesy http//www.fcc.gov/realaudio/presentatio
ns/2002/042602/IEEE_802-15.ppt
39
Implications for Applications

• UWB characteristics
• Simultaneously low power, low cost high data-rate
  wireless communications
• Attractive for high multipath environments
• Enables the use of powerful RAKE receiver
  techniques
• Low fading margin
• Excellent range-rate scalability
• Especially promising for high rates ( gt100 Mbps)
• Candidate Applications
• Wireless Video Projection, Image Transfer,
  High-speed Cable Replacement

Courtesy http//www.fcc.gov/realaudio/presentatio
ns/2002/042602/IEEE_802-15.ppt
40
Challenges for UWB

• Wide RF Bandwidth Implementation
• In-Band Interference
• Signal Processing Beyond Current DSP (today
  requires analog processing)
• Global Standardization
• Broadband Non-resonant Antennas

Courtesy http//www.fcc.gov/realaudio/presentatio
ns/2002/042602/IEEE_802-15.ppt
41
The 802 Wireless Space
Source http//www.zigbee.org/en/resources/
Courtesy http//homepage.uab.edu/cdiamond/ZigBee.
ppt
42
IEEE 802.15.4 ZigBee In Context
Application
Customer

• the software
• Network, Security Application layers
• Brand management
• IEEE 802.15.4
• the hardware
• Physical Media Access Control layers

API
Security 32- / 64- / 128-bit encryption
ZigBee Alliance
Network Star / Mesh / Cluster-Tree
MAC
IEEE 802.15.4
PHY 868MHz / 915MHz / 2.4GHz
Stack
Silicon
App
Source http//www.zigbee.org/resources/documents/
IWAS_presentation_Mar04_Designing_with_802154_and_
zigbee.ppt
Courtesy http//homepage.uab.edu/cdiamond/ZigBee.
ppt
43
Applications

• Designed for wireless controls and sensors
• Environmental Monitoring
• Agricultural Monitoring
• Home Automation Still on Horizon
• Control of lights, switches, thermostats,
  appliances, etc.
• Connectivity between small packet devices

Source ZigBee Specification Document
Courtesy http//homepage.uab.edu/cdiamond/ZigBee.
ppt
44
ZigBee/802.15.4 Technology General
Characteristics

• Data rates of 250 kbps , 20 kbps and 40kpbs.
• Star or Peer-to-Peer operation.
• Support for low latency devices.
• CSMA-CA channel access.
• Dynamic device addressing.
• Fully handshaked protocol for transfer
  reliability.
• Low power consumption.
• 16 channels in the 2.4GHz ISM band, 10 channels
  in the 915MHz ISM band and one channel in the
  European 868MHz band.
• Extremely low duty-cycle (lt0.1)

Courtesy http//www.centronsolutions.co.uk/docs/z
igbee-802.15.45B15D.ppt
45
IEEE 802.15.4 Basics

• 802.15.4 is a simple packet data protocol for
  lightweight wireless networks
• Channel Access is via Carrier Sense Multiple
  Access with collision avoidance and optional time
  slotting
• Message acknowledgement and an optional beacon
  structure
• Multi-level security
• Works well for
• Long battery life, selectable latency for
  controllers, sensors, remote monitoring and
  portable electronics
• Configured for maximum battery life, has the
  potential to last as long as the shelf life of
  most batteries

Courtesy http//www.centronsolutions.co.uk/docs/z
igbee-802.15.45B15D.ppt
46
IEEE 802.15.4 PHY Overview

• PHY functionalities
• Activation and deactivation of the radio
  transceiver
• Energy detection within the current channel
• Link quality indication for received packets
• Clear channel assessment for CSMA-CA
• Channel frequency selection
• Data transmission and reception

Courtesy http//www.centronsolutions.co.uk/docs/z
igbee-802.15.45B15D.ppt
47
Channel Access Mechanism

• Two type channel access mechanism, based on the
  network configuration
• In non-beacon-enabled networks ? unslotted
  CSMA/CA channel access mechanism
• In beacon-enabled networks ? slotted CSMA/CA
  channel access mechanism
• The superframe structure will be used.
• GTS mechanism

Courtesy http//www.centronsolutions.co.uk/docs/z
igbee-802.15.45B15D.ppt
48
Superframe Structure

• A superframe is divided into two parts
• Inactive all stations sleep
• Active
• Active period will be divided into 16 slots
• 16 slots can further divided into two parts
• Contention access period
• Contention free period
• (These slots are MACRO slots.)

Courtesy http//www.centronsolutions.co.uk/docs/z
igbee-802.15.45B15D.ppt
49
GTS Concepts

• A guaranteed time slot (GTS) allows a device to
  operate on the channel within a portion of the
  superframe.
• A GTS shall only be allocated by the PAN
  coordinator.
• and is announced in the beacon.
• The PAN coordinator can allocated up to seven
  GTSs at the same time
• The PAN coordinator decides whether to allocate
  GTS based on
• Requirements of the GTS request
• The current available capacity in the superframe

Courtesy http//www.centronsolutions.co.uk/docs/z
igbee-802.15.45B15D.ppt
50
Battery Life Extension
Courtesy http//www.centronsolutions.co.uk/docs/z
igbee-802.15.45B15D.ppt
51
Comparison Between WPAN
Courtesy http//www.centronsolutions.co.uk/docs/z
igbee-802.15.45B15D.ppt
52
RFID Radio Frequency Identification (1)

• Data rate
• Transmission of ID only (e.g., 48 bit, 64kbit, 1
  Mbit)
• 9.6 115 kbit/s
• Transmission range
• Passive up to 3 m
• Active up to 30-100 m
• Simultaneous detection of up to, e.g., 256 tags,
  scanning of, e.g., 40 tags/s
• Frequency
• 125 kHz, 13.56 MHz, 433 MHz, 2.4 GHz, 5.8 GHz and
  many others
• Security
• Application dependent, typ. no crypt. on RFID
  device
• Cost
• Very cheap tags, down to 1 (passive)
• Availability
• Many products, many vendors

• Connection set-up time
• Depends on product/medium access scheme (typ. 2
  ms per device)
• Quality of Service
• none
• Manageability
• Very simple, same as serial interface
• Special Advantages/Disadvantages
• Advantage extremely low cost, large experience,
  high volume available, no power for passive RFIDs
  needed, large variety of products, relative
  speeds up to 300 km/h, broad temp. range
• Disadvantage no QoS, simple denial of service,
  crowded ISM bands, typ. one-way (activation/
  transmission of ID)

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RFID Radio Frequency Identification (2)

• Function
• Standard In response to a radio interrogation
  signal from a reader (base station) the RFID tags
  transmit their ID
• Enhanced additionally data can be sent to the
  tags, different media access schemes (collision
  avoidance)
• Features
• No line-of sight required (compared to, e.g.,
  laser scanners)
• RFID tags withstand difficult environmental
  conditions (sunlight, cold, frost, dirt etc.)
• Products available with read/write memory,
  smart-card capabilities
• Categories
• Passive RFID operating power comes from the
  reader over the air which is feasible up to
  distances of 3 m, low price (1)
• Active RFID battery powered, distances up to 100
  m

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RFID Radio Frequency Identification (3)

• Applications
• Total asset visibility tracking of goods during
  manufacturing, localization of pallets, goods
  etc.
• Loyalty cards customers use RFID tags for
  payment at, e.g., gas stations, collection of
  buying patterns
• Automated toll collection RFIDs mounted in
  windshields allow commuters to drive through toll
  plazas without stopping
• Others access control, animal identification,
  tracking of hazardous material, inventory
  control, warehouse management, ...
• Local Positioning Systems
• GPS useless indoors or underground, problematic
  in cities with high buildings
• RFID tags transmit signals, receivers estimate
  the tag location by measuring the signals time
  of flight

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RFID Radio Frequency Identification (4)

• Security
• Denial-of-Service attacks are always possible
• Interference of the wireless transmission,
  shielding of transceivers
• IDs via manufacturing or one time programming
• Key exchange via, e.g., RSA possible, encryption
  via, e.g., AES
• Future Trends
• RTLS Real-Time Locating System big efforts to
  make total asset visibility come true
• Integration of RFID technology into the
  manufacturing, distribution and logistics chain
• Creation of electronic manifests at item or
  package level (embedded inexpensive passive RFID
  tags)
• 3D tracking of children, patients