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Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 1
COMP 437 Mobile Computing Overview of Mobile Computing
Overview of Mobile Computing
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 2
COMP 437 Mobile Computing Overview of Mobile Computing
Outline
What is mobile computing?
Mobile computing applications
Basic concepts of mobile computing
Challenges in mobile computing
Topics in mobile computing
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 3
COMP 437 Mobile Computing Overview of Mobile Computing
What is mobile computing?By 2012 the number of mobile subscribers throughout the world will reach 5 Billion, of which close to 1.5 Billion will use wireless communicators (3G) as gateways to the Internet
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 4
COMP 437 Mobile Computing Overview of Mobile Computing
What is mobile computing?World wide Internet penetration rate increases rapidly.
25% of the world population access to the Internetby 2012, >1 billion of Internet users will use mobile as their only access means
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 5
COMP 437 Mobile Computing Overview of Mobile Computing
What is mobile computing?Today, access to information and computing services is necessary everywhere
not only from our "home base," but also while we are traveling and when we reach a different location.
Mobile computing Techniques that allow mobile users to use portable computing devices to run stand-alone applications and / or to access remote ones via wireless networks.
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 6
COMP 437 Mobile Computing Overview of Mobile Computing
What is mobile computing?Mobile computing = mobile + computing, another wave in computing evolution.Different kinds of mobility
Terminal mobility: movement of processors / devices - caused by mobile devices.User mobility: movement of users – caused by traveling people.Logical mobility: movement of processes - caused by mobile codes.
Different modes of computingSmall office: take the service/application with users - computing is offlineHome office: maintain the access to the same service/application at different places – computing is onlineMobile office: move to different places and the service/application follows – computing is moving (follow-me)
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 7
COMP 437 Mobile Computing Overview of Mobile ComputingEvolution of computing
paradigm
2010Unwired
Enterprise
1980
Branch
Age of DistributedComputing
Client/Server
1990
Office
Age of Personal
Computing
Personal Computer
2000
Remote Office
Age of NetworkedComputing
Internet
2003
Mobile Workplace
Age ofMobile
Computing
Mobile Internet
1960
Fixed Location
Age of Centralized Computing
Mainframe
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 8
COMP 437 Mobile Computing Overview of Mobile Computing
Mobile computing often uses wireless and mobile networks as access technologies.
Wireless and mobile networks extend networking capacity to cover the areas of lack of wired link and support movement of devices
Wireless communication plays an important role in mobile computing. But, mobile computing does not necessarily mean wireless.
What is mobile computing?
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 9
COMP 437 Mobile Computing Overview of Mobile Computing
Wireless mobile Examples
stationary computer
notebook in a hotel room
wireless LANs in historic buildings
Personal Digital Assistant (PDA)
Wireless vs mobile
mobile wireless
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 10
COMP 437 Mobile Computing Overview of Mobile Computing
Today’s applications
WAP GatewayMerchant 1
WAP / Agent Server
Merchant n
Internet
ProviderNetwork
WAP Terminal
SQL
SQL
SQL
- WML pages- list of merchants
Products
Products
Internet, Wireless Networks & Mobile ComputingMobile users use wireless communications to access to the Web information and services
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 11
COMP 437 Mobile Computing Overview of Mobile Computing
CorporationsM-business / M-office (working remotely - job dispatch, calendar, email, workflow, etc)M-commerce (logistics, inventory control)
ConsumersM-commerce (shopping, banking, payment, etc)Mobile web access / mobile email / SMSMobile P2P (file sharing, gaming, etc.)
Government / Public services / MilitariesM-healthcare (emergency with in-time patient condition info.)TransportationTourism (navigation with maps, location-aware travel hints, etc)Intelligent homeEnvironment monitoringBattle field communications
Today’s applications
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 12
COMP 437 Mobile Computing Overview of Mobile Computing
Enabling factorsMotivations and driving forces
Increasing demands on access to information, communication, and cooperation anywhere, anytime, anyway.Technology reality may support such demands
Increasing availability of wireless networks at reduced cost. Widespread use of handheld devices with increasing computing power and lower cost.Integration of communication and computing devices (PDA, i-Phone, smart phone, intelligent sensor).
Advances in techniques of detecting location of a device – location based services.
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 13
COMP 437 Mobile Computing Overview of Mobile Computing
Open Mobile Alliance (OMA)
No matter whatdevice I haveservice I wantcarrier or network I am using
I can communicate, access and exchange information
Visions
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 14
COMP 437 Mobile Computing Overview of Mobile Computing
Wireless Vision: ubiquitous communication
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 15
COMP 437 Mobile Computing Overview of Mobile Computing
Device VisionMobile phones
1973: First cellphone call
2007: ~ 3.3 billion mobile phone subscribers
2009: ~ 4.6 billion
Smart phones are mobile phoneshave operation systemscan connect to the internet: web browsing, email, etchave advanced computing ability: send and receive text & multimedia messages (SMS, MMS), take pictures, etc
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 16
COMP 437 Mobile Computing Overview of Mobile Computing
Convergences
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 17
COMP 437 Mobile Computing Overview of Mobile ComputingMobile computing means
more…Mobile computing has a close relationship with distributed computing
Distributed computing: coordination of utilizing computing resources shared by multiple hosts over a network.
Mobile computing: extends distributed computing with new dimensions of mobility and wireless connection.
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 18
COMP 437 Mobile Computing Overview of Mobile ComputingMobile computing means
more…Mobile computing is also closely related to Internet computing technologies
Mobile computing uses Internet computing technologies
The layered protocol stack and client/server paradigm
Mobile computing allows the application not to connect the network all the time
Mobile Internet, Wireless Internet
HTTP client / server protocols => WAP
XML, HTML => WML, XHTML
J2SE/J2EE, .Net => J2ME/J2EE, .Net Mobile
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 19
COMP 437 Mobile Computing Overview of Mobile ComputingMobile computing means
more…Pervasive computing
Create a smart environment with ubiquitous, invisible, interconnected devices that provides services to the users without being noticed.
Improving users’ experience and quality of life without requiring them know the underlying technologies.
Mark Weiser, “The Computer for the 21st Century,” Sci. Amer., Sept., 1991.
“The most profound technologies are those that disappear. They weave themselves into the fabric of everyday life until they are indistinguishable from it.”
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 20
COMP 437 Mobile Computing Overview of Mobile Computing
Pervasive computing era
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 21
COMP 437 Mobile Computing Overview of Mobile Computing
Mobile computing means more…
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 22
COMP 437 Mobile Computing Overview of Mobile Computing
Tomorrow…
Pervasive and Mobile ComputingComputing is everywhere, invisible, and moving with you
WLAN Cellular
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 23
COMP 437 Mobile Computing Overview of Mobile Computing
Forthcoming applicationsExample: Vehicle Networks
transmission of news, road condition, traffic information, weather, music via DABpersonal communication using mobile phone networkspositioning via GPSlocal ad-hoc network with vehicles close-by to prevent accidents, report traffic jams, guidance system, etcvehicle data (e.g., from busses, high-speed trains) can be transmitted in advance for maintenance busses, trucks, and trains can transmit logistic information for, e.g., fleet management.
ad ho
cUMTS, WLAN,GSM, cdma2000, DAB, ...
Personal Travel Assistant,DAB, PDA, laptop, GSM, UMTS, WLAN, Bluetooth, ...
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 24
COMP 437 Mobile Computing Overview of Mobile Computing
Example: Intelligent lifeSystem knows your current location, and light turns on as you enter a room, and the seat you are sitting on is adjusted to your size.Your active ID-badge indicates your identity (and your preferences). So brightness can be adjusted also based on your preference.Music will continue when you leave a room and enter another.When you enter a range of 5 km of your home, the air-conditioner will be turned on so you get a cool environment upon arriving home.When you attend MTR, you are automatically connected to a group of people sharing the same interest with you in music, sports, games etc.
Forthcoming applications
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 25
COMP 437 Mobile Computing Overview of Mobile Computing
What’s the future picture?
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 26
COMP 437 Mobile Computing Overview of Mobile Computing
Wireless: Convergence
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 27
COMP 437 Mobile Computing Overview of Mobile ComputingPervasive Internet of
“Things”…
The Economist, April 28, 2007
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 28
COMP 437 Mobile Computing Overview of Mobile Computing
Seamless Mobility
1xRTT / GPRSPDA
WiFi / 1x/ 3G PC
GSM / CDMAMobile
DeskPhone
PCLAN
LAN
PBX
DSL
LaptopPC
Headset
HomePhone
Phone
Web Kiosk
Corporate fixed / mobileCommunications
IP
User Mobility
Device Mobility
Network Mobility
PCWLAN
Mobile / PDA(eg. P900)
Work is something you do, not somewhere you goWork is something you do, not somewhere you go
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 29
COMP 437 Mobile Computing Overview of Mobile ComputingChallenges of mobile computing
Where do the challenges come from? Distinct characteristics of mobile and wireless computing:
Wireless communications
Mobility
Mobile devices
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 30
COMP 437 Mobile Computing Overview of Mobile Computing
Wireless communicationsBoth wired and wireless communications are about transmission of data by the propagation and processing of signals over a transmission medium
Data – an abstract entity that conveys meaning or informationSignals - electric or electromagnetic representations of data in the physical worldTransmission medium - physical path between transmitter and receiver
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 31
COMP 437 Mobile Computing Overview of Mobile Computing
Wireless communications
Transmission mediumGuided Media
Signals are guided along a solid mediume.g., copper twisted pair, copper coaxial cable, optical fiber
Unguided MediaProvides means of transmission but does not guide electromagnetic signalsUsually referred to as wireless transmissione.g., atmosphere, outer space, water
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 32
COMP 437 Mobile Computing Overview of Mobile Computing
Wireless communicationsA wireless communication does not use wires (cables) for communications, but by the transmission of electromagnetic waves through ‘the air’.
Michael faraday, James C. Maxwell, Heinrich Hertz
Wireless communication has a long history, started in 1896 - Guglielmo Marconi invented the wireless telegraph
Advances in wireless technology include radio, television, mobile telephone, communication satellites.
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 33
COMP 437 Mobile Computing Overview of Mobile Computing
Wireless communicationsElectromagnetic waves are produced and received via antennas
Transmitting antenna - a transmitter delivers radiates alternating current into the surrounding environment in the form of radio or microwave signals
Receiving antenna - converts signals from the environment into alternating current and delivers it to the receiver.
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 34
COMP 437 Mobile Computing Overview of Mobile Computing
ChallengesWired channel
Wired channel can be easily engineeredToo many noises? – use shell to protect against electromagnetic noiseLarge signal attenuation? - use repeaters to amplify the signalData rate too low? - upgrade to coaxial cable or optical fiberLow error rate - Good quality: 10-6; Optical fiber: 10-11 ~ 10-12
Wireless channelWireless channel is hardly be engineered
High background noisesSignal strength fluctuates significantlyLow data rateHigh error rate – Radio: 10-2 or worse
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 35
COMP 437 Mobile Computing Overview of Mobile Computing
Wired channel – what if more than one transmitter?
Switching Center
or
Network Access Point
Every user accesses the network by means of a dedicated channelNew user is served by a new wired-line circuit
Access capacity is guaranteed.
Dedicated Channel
Challenges
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 36
COMP 437 Mobile Computing Overview of Mobile Computing
Wireless channel – what happens?
Base Station
Shared Channel
Wireless users access the network by means of a shared channel
Access capacity is inherently limited.
Challenges
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 37
COMP 437 Mobile Computing Overview of Mobile Computing
Wireless channelLow and asymmetric bandwidth
High latency
High error rate
Large variation in available bandwidthBandwidth differences with orders of magnitude from open-space wireless to indoor wireless
Frequent disconnectionsNetwork failure is commonUser’s movement is frequent
Shared radio channelIncreased security risks
Challenges
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 38
COMP 437 Mobile Computing Overview of Mobile Computing
Mobility
Different entities of mobility
Physical / Terminal mobility
User mobility
Logical mobility
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 39
COMP 437 Mobile Computing Overview of Mobile Computing
MobilityDifferent modes of mobility
Personal mobility : reaching a mobile user using a logical identity, irrespective of what device he/she is using, current location in the network, or even which network he/she is located inSession mobility : maintaining access to the same network service / application at different placesService / application mobility : making a service/application available to mobile user when the user has moved to another location with other but similar resources (e.g., print using the nearest printer) – following me service
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 40
COMP 437 Mobile Computing Overview of Mobile Computing
ChallengesDynamic change of physical locations
Mobile users may use their phones at different places
Dynamic change of logical addressesUsers may use their laptops to access different networks
Frequent change of system configuration
Mobile users may use PDAs with cellular networks when outdoor and with WLANs when indoor.
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 41
COMP 437 Mobile Computing Overview of Mobile Computing
Location dependencyLocation management problem: How does the network know where the intended recipient of a message is currently located?
Cellular scenario
Where is 97532468?
Send broadcast messages from every base station.
Challenges
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 42
COMP 437 Mobile Computing Overview of Mobile Computing
Mobile devices
PagersCellular phonesPortable media playersPersonal digital assistants (PDAs)Tablet PCsLaptop computersMobile Internet devices (MIDs)
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 43
COMP 437 Mobile Computing Overview of Mobile Computing
Mobile computing devices are becoming smaller, cheaper, more powerful and better integrated
Small screen display sizeNo keyboard, only some buttonsSmall storage capacityLimited computation capabilityLimited battery powerLarge variations in design & usageFrequent disconnection & a short life span
Challenges
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 44
COMP 437 Mobile Computing Overview of Mobile Computing
Need new solutions to old / new problems to overcome the above constraints
Need to Reduce communication and operational costNeed to manage mobilityNeed to conserve energyNeed to design special interfaces for small devicesNeed to enforce wireless security Need to have new computing paradigms
asynchronous interactionshandling of disconnectionsadaptation (may need user’s involvement)mobile code and mobile agent
Cope with challenges
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 45
COMP 437 Mobile Computing Overview of Mobile Computing
The challenges can be tackled in various system components including
Mobile devices
Mobile wireless networks and protocols
Location tracking techniquesMobile computing models, application architectures, and software infrastructureProtocols, OS, and programming languagesApplication / user requirements, business models
Cope with challenges
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 46
COMP 437 Mobile Computing Overview of Mobile Computing
Topics in mobile computing
Wireless communications and networks
Modulation techniques, Multiplexing techniques, Medium access control (MAC), Routing, etc.
Design of different types of wireless networks
Cellular, WLAN, WPAN, WMAN, Satellites
Wireless ad hoc networks (WSN, MANET)
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 47
COMP 437 Mobile Computing Overview of Mobile Computing
Topics in mobile computing
Wireless communications and networks
Wireless networks can be classified in different ways
Short range vs. Long range
Infrastructured vs. Ad hoc
Heterogeneous
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 48
COMP 437 Mobile Computing Overview of Mobile Computing
Wireless communications and networksShort-range wireless pertains to networks that are confined to a limited area.
Local area networks (LAN): cover corporate building, school campuses, manufacturing plants, homes.Personal area networks (PAN): connect portable computers within close proximity to one another.
Operate over unlicensed spectrum reserved for industrial, scientific, medical usage (ISM)
No need to obtain a license, and free of chargeThe most common frequency band is at 2.4 GHzOther bands at 5GHz and 40GHz are also often used.
Topics in mobile computing
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 49
COMP 437 Mobile Computing Overview of Mobile Computing
Wireless communications and networksLong-range wireless networks span large areas - a metropolitan area, a state or province, an entire country, or across world.
The goal is to provide wider-area or even global coverage
Typically provided by companies that sell the wireless connectivity as a service.
Charging either by the minute or by the amount of data transferred.
Topics in mobile computing
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 50
COMP 437 Mobile Computing Overview of Mobile Computing
Wireless communication and networksInfrastructure-based wireless networks
mobile computers /devices connect to a wired network via hubse.g., cellular systems (base station infrastructure)e.g., a laptop access internet via WLAN access points
Topics in mobile computing
Fixed, wired backbone;Mobiles connectto Access Points.
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 51
COMP 437 Mobile Computing Overview of Mobile Computing
Wireless communication and networksAd hoc wireless networks
No infrastructure required, temporarily setup a network to meet immediate needse.g., rescue, home networking, military applicationse.g., wireless sensor networks
Topics in mobile computing
No wired backbone;Peer-to-peer;Multi-hop routes
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 52
COMP 437 Mobile Computing Overview of Mobile Computing
Wireless communication and networksHeterogeneous networks: integrated network combining different kinds of wireless & wired networks
Topics in mobile computing
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 53
COMP 437 Mobile Computing Overview of Mobile Computing
Wireless networks issuesThe essential aspects of differrent wireless networks are the same.
They share a common foundation in the design of
physical layer,
median access,
network planning and deployment, and
network operation.
Topics in mobile computing
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 54
COMP 437 Mobile Computing Overview of Mobile Computing
Mobile computing modelsMobile C/S Models
Simple C/S model, Client/Agent/Server model, Client/Intercept/Server model
Mobile Peer-to-Peer ModelMobile hosts plays the same role and cooperate to Discover peers and resources Route query requests Perform specified tasks
Mobile Agent ModelCode mobility (with computation, data, and state)Autonomous and Asynchronous
Topics in mobile computing
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 55
COMP 437 Mobile Computing Overview of Mobile Computing
Mobile C/S modelC/S model can still be used in mobile environment - mobile hosts act as the clients requesting service from server located at fixed network.
However, mobile C/S model deviates from the C/S model used for distributed system in several ways. Mobile C/S model cannot assume continuous network connectivity and powerful client ability
RPC (Remote process control) is not suitable due to disconnection; Direct message exchange is not good neither due to weak connectivity and slow network.Need to decouple the communication in synchronous RPC; Use indirection with messages queued at the two ends.
Topics in mobile computing
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 56
COMP 437 Mobile Computing Overview of Mobile Computing
Mobile C/S modelNo clear division of functionality between mobile client and server at the fixed networkResource limitation on mobile client justifies moving client activities to server side (“thin client”); However, client can not be too “thin”, since disconnection and low bandwidth force us to place some processing ability on client for disconnected operations (“smart client”)
Need synchronization between client and server
Topics in mobile computing
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 57
COMP 437 Mobile Computing Overview of Mobile Computing
Mobile C/S issuesOptimization
Data compressing / filtering
Mobile date managementData dissemination and broadcast
Caching and invalidation
Disconnected operations
Location based services
Context-aware adaptation
Topics in mobile computing
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 58
COMP 437 Mobile Computing Overview of Mobile Computing
Mobile P2P modelNo central server, actually no difference between client and server:
All nodes have the same role, serving as both server and clientRelying on collaboration
Completely decentralized & asynchronous operationsNodes can communicate with each other directly
Topics in mobile computing
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 59
COMP 437 Mobile Computing Overview of Mobile Computing
Mobile P2P applicationsData sharing and disseminationInstant messagingCollaborationEntertainment (e.g., gaming)…
Topics in mobile computing
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 60
COMP 437 Mobile Computing Overview of Mobile Computing
Mobile P2P featuresGood programming model for ad hoc network
Good architecture for cooperative applications
Server side can also move: more flexible
Good system scalability
Both sides need resource rich devices
Complexity in protocol design
Topics in mobile computing
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 61
COMP 437 Mobile Computing Overview of Mobile Computing
Mobile P2P issuesRapid mutual peer discovery and connection establishment
Message routing between peers
Data sharing among peersSearching / discovery (routing of queries)
Caching and invalidation
Security
Topics in mobile computing
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 62
COMP 437 Mobile Computing Overview of Mobile Computing
Mobile agent (MA) modelA MA is a “process on the move” – dispatched by one host, encapsulating a thread of execution along with a package of code, data, and execution state
Executes at a host for a while, halts execution, dispatches itself to another host, and resumes execution there - all under its own control
mobile agent X
logic
mobile agent X
logic
Host A Host B
Migratingmobile agent
X
logic
Topics in mobile computing
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 63
COMP 437 Mobile Computing Overview of Mobile Computing
Mobile agent featuresMobility
Actively travels across the network, carrying partial / intermediate results calculated at the previous hostNot just alternative to message passing; can perform additional tasks along its way of traveling
AutonomousDecides by itself what to do and how, when and where it ought to move
AsynchronyMobile agents and users can execute at the same time without blocking each other
Topics in mobile computing
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 64
COMP 437 Mobile Computing Overview of Mobile Computing
Mobile agent advantages
Reducing remote communicationPerform tasks locally: save network bandwidth
Intermediate result data is processed locally rather than transferred back and forth over the network
Go to the data if the data can’t come to you
Topics in mobile computing
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 65
COMP 437 Mobile Computing Overview of Mobile Computing
ClientAgent Service
ServerHost
MA model of service MA model of service providingproviding
Client
Host
Service
ServerNetwork
Network
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 66
COMP 437 Mobile Computing Overview of Mobile Computing
Mobile agent advantages
Overcome message passing latency
Local, “instant” interaction with the other party
Latest up-to-date information
Be adaptiveCan encapsulate policies and protocols
Topics in mobile computing
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 67
COMP 437 Mobile Computing Overview of Mobile Computing
Mobile agent advantagesSupport disconnected/intermittent connectivity, slow network.
Support disconnected/weak connectivity operation
Topics in mobile computing
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 68
COMP 437 Mobile Computing Overview of Mobile Computing
Mobile agent applications
Especially good for those mobile computing applications
Require long connection time and/or user has bad connection/highly mobility
User can disconnect and do something else while mobile agent performing tasks over the network
E.g., information search, retrieval, filtering, E-commerce, network management, etc.
Topics in mobile computing
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 69
COMP 437 Mobile Computing Overview of Mobile Computing
Mobile agent applications
Site B
Site A Site C
Site D
Dispatch
Computing
ComputingComputing
Computing
Site EReceive
Topics in mobile computing
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 70
COMP 437 Mobile Computing Overview of Mobile Computing
Site B
Site A Site C
Site D
Dispatch
Computing
Computing Computing
Computing
Site E
collaborating
Topics in mobile computingMobile agent applications
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 71
COMP 437 Mobile Computing Overview of Mobile Computing
Mobile agent issuesNeed powerful mobile devices if need to have mobile agent platform installed on devices
Fault tolerance
Security issue is the main obstacle
Topics in mobile computing
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 72
COMP 437 Mobile Computing Overview of Mobile Computing
Mobility managementTypes of mobility management
Handoff management
Location management
Mobility management in cellular networks
Mobility management in Mobile IP
Location services in MANET
Topics in mobile computing
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 73
COMP 437 Mobile Computing Overview of Mobile Computing
Topics in mobile computing
Protocols / algorithms for resource-constrained mobile environments
MAC protocols
Routing protocols
Clustering
Synchronization
Data dissemination
Data aggregation
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 74
COMP 437 Mobile Computing Overview of Mobile Computing
Location based servicesMobile positioning techniques
Cellular phone positioning Network-based vs Handset based solutions
GPSWLAN positioningOther technologies (in-door, road beacon, identity)
Location-based servicesGIS
LBS architecture
Topics in mobile computing
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 75
COMP 437 Mobile Computing Overview of Mobile Computing
Mobile computing middleware
Service discovery in mobile computing
Security in mobile computing
Reliability in mobile computing
Topics in mobile computing
Wei Lou @ Department of Computing, Hong Kong Polytechnic Univ.
Slide 76
COMP 437 Mobile Computing Overview of Mobile Computing
Related journal & conferences
IEEE Transactions on Communications IEEE Transactions on Parallel and Distributed SystemsIEEE/ACM Transactions on Networking IEEE Transactions on Vehicular TechnologyIEEE Transactions on Computers Transactions on Mobile ComputingMobile Networks & ApplicationsIEEE Communications MagazineMobile Computing and Communications ReviewProceedings of the MOBICOMProceedings of the MOBIHOCProceedings of the INFOCOMProceedings of the GLOBECOMProceedings of the Vehicular Technology ConferenceProceedings of ICDCS…