Outline Internet of Things (IoT) Enabling Technologies RFID
Mobile Cloud Computing
Slide 3
Things A real/physical or digital/virtual entity that exists
and moves in space and time 3 Examples: computers, sensors, people,
actuators, refrigerators, TVs, vehicles, mobile phones, clothes,
food, medicines, books, passports, luggage,..
Slide 4
Explosion of connected things
(devices/terminals/phones/sensors) 4
Slide 5
Internet of Things (IoT) Visions IoT allows people and things
to be connected 5 Anyone can use anything to access any service and
any network at anytime any place
Slide 6
199520042005 2008 2009-6future IoT concept U-Korea IBM: Smart
Planet Sensing China 2009-8 Internet of Things action plan for EU
ITU Internet Report 2005 The Internet of Things U-Japan IoT
development
Slide 7
IoT Application: Connected Vehicles for driving safety View for
the driver in the 2 nd yellow car
Slide 8
Connected Road: addressable sensors on the road and can be
networked Increase safety Road surface temperature Road condition
ice/snow/rain/dry/wet Tyre pressure monitoring Estimate traffic
Number of vehicles passed in 15 minutes 8 Sensors on the road
Slide 9
Outline Internet of Things (IoT) Enabling Technologies RFID
Wireless Sensor Networks
Slide 10
ENABLING TECHNOLOGIES: RFID 10
Slide 11
RFID (Radio Frequency Identification) RFID principle: devices
are wireless microchips used for tagging objects for automated
identification RFID can identify objects wirelessly without
line-of-sight 11
Slide 12
RFID systems RFID systems consist of Readers: read and write
tag data Tags: carry object identification data Back-end database
12
Slide 13
Tags Passive tags No energy source, harvesting RF energy Short
communication range, 10meter Communications: response only Low
price Active Tags Battery operated Long communication ranges, 100m+
Communications: response or initiate High price 13 Semi-Passive
tags Battery operated long communication range, 100+ Communication:
response only High price
Slide 14
Which tags are used in the applications? ApplicationsActive,
Semi-passive or Passive Tags Reisekort Shipping containers Large
assets tracking 14 Passive Active
Slide 15
Which tags are used in the applications? ApplicationsActive,
Semi-passive or Passive Tags Electronic toll Tracking components
like automobile parts during manufacture electronic product code 15
Semi-Passive Passive
Slide 16
Tag 1 reader Tag 2 Tag 3 Reading range Readers reading range
16
Slide 17
Reading range Tag Reader Tags collision problem 17 Collision
occurs when multiple tags respond to the same reader at the same
time. The reader is unable to differentiate these signals. Tag
collision results in wastage of energy, increases identification
delays. Readers must use an anti- collision protocol to minimize
collisions and help reduce identification delays
Slide 18
RFID anti-collision protocols: Aloha based protocols Pure Aloha
Slotted Aloha Framed Slotted Aloha 18
Slide 19
An example of ALOHA RFID anti-collision: Pure Aloha Easy to
implement If a tag has data to send, send the data If the message
collides with another tag, try resending "later On collision,
sender waits random time before trying again A tag responds after a
random delay, and continues until identified. Low efficiency: 18.4%
19 Tag1 Tag2 Tag3 Tag4 Tag5 Tag6 Tag7 Tag8 Tag9 Tag10
Collision
Slide 20
S: time slot An example of slotted ALOHA protocol RFID
anti-collision: Slotted Aloha S-ALOHA divides time into timeslots.
Each tag can send out data at the beginning of a timeslot. A tag
responds in synchronized slots after random delay Efficiency: 36.8%
20 S1S2S3S4S5S6S7S8S9S10S11 Tag1 Tag2 Tag3 Tag4 Tag5 Tag6 Tag7 Tag8
Tag9 Tag10 Collision
Slide 21
Pure Aloha vs Slotted Aloha 21 Slotted Aloha Pure Aloha
Slide 22
RFID anti-collision: Frame-Slotted Aloha A tag randomly selects
a slot to respond only once in a frame. If there is a collision,
tags respond in the next frame 22 Frame 1 Frame 2Frame 3 Tag 1 Tag
2 Tag 3 channel collision
Slide 23
Collisions Tags collision Collision between readers?
Slide 24
RFID readers collision Reader-to-Tag When a tag enters an
overlapping area of two readers, transmitted signals will collide
and tags will be unable to answer readers queries AB Reader As
reading range Reader Bs reading range Tag
Slide 25
RFID readers collision Reader-to-Reader AB Reader As reading
range Reader Bs reading range Rr Reader Bs interference range R i =
(1+ ) * R r Tag
Slide 26
Coverage based approach for Readers Anti-collision The reading
ranges of readers are adapted dynamically to reduce the overlapped
areas between adjacent readers Advantage: increases the space
re-used ratio Disadvantage: needs a central node to calculate the
distance between two readers and adjust their reading ranges, which
will increase the complexity of realization and cost of the system
26 AB Reader As reading range Reader Bs reading range Rr Tag
Slide 27
Scheduling based Readers Anti- collision Resources (e.g.,
frequencies and time) are allocated properly among readers to
prevent readers from transmitting simultaneously Advantage: reduce
readers collision effectively Disadvantage: requires the system to
maintain information over the network, which will be time and
energy consuming 27 AB Tag -Reader A transmits -after some time,
e.g., 1sec -Reader B transmits
Slide 28
ENABLING TECHNOLOGIES: MOBILE CLOUD COMPUTING 28
Slide 29
MCC = Mobile + Cloud Computing Cloud Cloud Mobile network Cloud
computing 3G/wifi/WiMAX
Slide 30
Mobile Devices/Terminals/Machines Smart phones Laptops Tablet
(e.g., Apple iPad, Samsung Galaxy Tab, Sony Xperia) Sensors,
actuators, robots Embedded systems (e.g., RFID readers and tags)
Vehicles Glasses Satellites and many more
Slide 31
Resource-constrained Devices: mobile phone as a sensor node
Modern mobile devices have many sensors to obtain location &
environmental information Huge sensed data can be collected,
transmitted, processed, and monitored. Devices will deal with
explosive traffic, but they are constrained by resources Low
computation Limited bandwidth Low storage Battery powered device
with limited energy Mobile devices should interact with cloud and
place computation-intensive and storage-intensive tasks to the
cloud Accelerometer Proximity Sensor Camera Light Sensor Microphone
GPS WiFi Bluetooth
Slide 32
MCC definition Mobile Cloud Computing at its simplest refers to
an infrastructure where both the data storage and the data
processing happen outside of the mobile device. Mobile cloud
applications move the computing power and data storage away from
mobile phones and into the cloud, bringing applications and mobile
computing to not just smart phone users but a much broader range of
mobile subscribers - Mobile Cloud Computing Forum definition
Slide 33
MCC 1 st Perspective: using mobile devices to access cloud
Infrastructure mode
Slide 34
MCC 2 nd Perspective: mobile devices are cloud Ad hoc mode: use
mobile devices for a self-organized cloud Share resources
(computation, storage, bandwidth) among devices Run complicated
cloud services by mobile devices Online Services Mobile Media
Urgent Tasks
Slide 35
MCC advantages Extending battery lifetime Improving data
storage capacity and computation capability Improving data
reliability and security
Slide 36
1 st advantage: battery lifetime improvement Challenge I hate
to charge iPhone everyday! Many applications are computation
intensive. Voice recognition, e.g., Siri Mobile gaming Real-time
navigation Searching Face recognition MCC provides Computation can
be performed in the cloud Save a lot of energy at mobile
devices
Slide 37
2 nd advantage: storage and processing power improvement
Challenge Users need more storage to save data iPhone 6 has max
128G MCC provides Mobile users can store and access the large data
on the cloud through wireless networks Example service Flickr
Slide 38
3 rd advantage: reliability improvement Challenge Users need
more reliable backup solution Lack of data security model MCC
provides Data and application are stored and backed up on a number
of computers in the cloud. An effective way to improve the
reliability
Slide 39
MCC challenges Wireless Communication side Limited radio
bandwidth Network latency Availability Device side Limited energy
Computation side Computation offloading Data access efficiency
Context-aware cloud services
Slide 40
OFFLOADING FOR MOBILE CLOUD
Slide 41
Computation Offloading Mobile devices have limited resources
battery lifetime network bandwidth storage capacity processor
performance Offloading: sending heavy computation to resourceful
servers and receiving the results from these servers. CloudCloud
Computation request Result: 6
Slide 42
Offloading schemes for energy-saving Saved energy C: the
computation needs C instructions S: the speed of cloud to compute C
instructions M: the speed of mobile device to compute C
instructions D: the data need to transmit B: the wireless bandwidth
P c : the energy cost when the mobile phone is doing computing P i
: the energy cost when the mobile phone is idle. P tr : the energy
cost when the mobile is transmitting the data
Slide 43
Energy-efficiency in offloading schemes Suppose the cloud is F
times fasteri.e., S = F M. Then, saved energy is Energy is saved
when this formula produces a positive number. The formula is
positive if D/B
