1. CPET 565 Mobile Computing Systems Introduction to Mobile Computing & Technologies Lecture 1 Spring 2010 Hongli Luo Indiana University-Purdue University Fort Wayne

2. Mobile Computing? Computer History Computer History Mainframe, Microcomputers, MicrocontrollersMainframe, Microcomputers, Microcontrollers Networking Networking Dialup, TCP/IP, Ethernet LAN, WAN, Wi-Fi,Dialup, TCP/IP, Ethernet LAN, WAN, Wi-Fi, Client-Server Computing Client-Server Computing Web server, File Server, Database serverWeb server, File Server, Database server Distributed Computing Distributed Computing Grid computing Grid computing Peer-to-peer Computing Peer-to-peer Computing Mobile Computing Mobile Computing

3. What is Mobile Computing? Computing enabled by presence of wireless enabled portable devices (PDAs, cell phones) Computing enabled by presence of wireless enabled portable devices (PDAs, cell phones) Some other names Some other names Pervasive computingPervasive computing Ubiquitous computingUbiquitous computing Wireless computingWireless computing Embedded computingEmbedded computing Wireless communication is needed Wireless communication is needed Focus on logical aspects of mobile communication Focus on logical aspects of mobile communication What kind of application can be enabled by mobile computing? What kind of application can be enabled by mobile computing? Design issues in mobile application and system Design issues in mobile application and system

4. What is Mobile Computing? Mobile Computing Mobile Computing Computing Platforms: PDAs, Smartphone, Pocket PCs, Tablet PCs, LaptopsComputing Platforms: PDAs, Smartphone, Pocket PCs, Tablet PCs, Laptops Networked embedded processors & appsNetworked embedded processors & apps Information & computing anytime, anywhereInformation & computing anytime, anywhere Distributed computing Distributed computing Nodes (computers)Nodes (computers) CommunicationsCommunications Computing tasksComputing tasks

5. Mobile Computing Applications User Groups Cellular phone/VoIP Cellular phone/VoIP Personal Information Management (PIM) Personal Information Management (PIM) Mobile Internet Access Mobile Internet Access Mobile Multimedia Entertainment Mobile Multimedia Entertainment Business User Applications Business User Applications Mobile Enterprise Mobile Enterprise Retail/Supply Chain Retail/Supply Chain Intelligent Transportation Intelligent Transportation Maintenance and Field Service Maintenance and Field Service Healthcare Healthcare Homeland Security/Emergency Homeland Security/Emergency Military Military

6. Mobile Computing Applications Email Email Internet access Internet access Personal Information Management (PIM) Personal Information Management (PIM) Instant Messaging Instant Messaging Data & information access Data & information access Context-aware applications Context-aware applications Audio streaming Audio streaming Video streaming Video streaming Cell phone Cell phone VoIP via WiFi VoIP via WiFi

7. Mobile Computing Applications Pervasive/ubiquitous computing: computing everywhere Pervasive/ubiquitous computing: computing everywhere Home appliances: refrigerator, washer/dryer, thermometer,Home appliances: refrigerator, washer/dryer, thermometer, microwave, dishwasher, what else - rumba the vacuum cleanermicrowave, dishwasher, what else - rumba the vacuum cleaner Mobile devices: laptop, PDA, PocketPC, iPhone, cell phonesMobile devices: laptop, PDA, PocketPC, iPhone, cell phones Home electronics: TV, DVD player, satellite TV set-top boxes, cdHome electronics: TV, DVD player, satellite TV set-top boxes, cd players, Stereos, iPod, Gameboy/Sony psp/Nintendo DSplayers, Stereos, iPod, Gameboy/Sony psp/Nintendo DS Location positioning devises – GPS, MPSLocation positioning devises – GPS, MPS Automobiles – every modern car is a network of computersAutomobiles – every modern car is a network of computers Tags – RFIDs, SmartCardsTags – RFIDs, SmartCards Sensor network and Smart DustSensor network and Smart Dust Smart homes, wearable computing, ….Smart homes, wearable computing, ….

8. Mobile Computing Constraints Resource-poor Resource-poor Battery packsBattery packs Hardware: Memory, CPU, peripheralsHardware: Memory, CPU, peripherals SoftwareSoftware Battery lifetime will see very small increase Battery lifetime will see very small increase Need energy efficient hardware and system softwareNeed energy efficient hardware and system software Planned disconnections – doze modePlanned disconnections – doze mode

9. Mobile Computing Constraints Less secure and less reliable Less secure and less reliable Lost or stolenLost or stolen Hostile or unfriendly environmentHostile or unfriendly environment Mobile connectivity Mobile connectivity Dynamic changes in environment: infrastructureDynamic changes in environment: infrastructure Highly variable: bandwidth, latencyHighly variable: bandwidth, latency Reliability: disconnectionsReliability: disconnections

10. What Needs to be Reexamined? Operating systems Operating systems File systems File systems Database systems Database systems Programming Languages Programming Languages Communication architecture and protocols Communication architecture and protocols Hardware and architecture Hardware and architecture Real-Time, multimedia, QoS Real-Time, multimedia, QoS Security Security Application requirements and design Application requirements and design

11. Adaptability – the Key to Mobile Computing Scenario – searching for information Scenario – searching for information Adaptive to location, user’s preferenceAdaptive to location, user’s preference Scenario - Video streaming application Scenario - Video streaming application Adaptive to available resource, video contentsAdaptive to available resource, video contents Continuous streamingContinuous streaming Routing video stream packets Routing video stream packets Access points Access points New IP address New IP address

12. Adaptability – the Key to Mobile Computing Vision Vision Adapt to dynamic changes in environmental and system conditionsAdapt to dynamic changes in environmental and system conditions System agilitySystem agility speed and accuracy with which an adaptive application detects and responds to change in computing environment speed and accuracy with which an adaptive application detects and responds to change in computing environment Roam seamlesslyRoam seamlessly Perform computing and communication task uninterruptedPerform computing and communication task uninterrupted E.g., mobile video streaming E.g., mobile video streaming Less human interventionLess human intervention

13. Adaptability – the Key to Mobile Computing Fundamental to mobile computing is various techniques in hardware/software to adapt to resource availability Fundamental to mobile computing is various techniques in hardware/software to adapt to resource availability Take into account contextual information including user preferencesTake into account contextual information including user preferences Wireless sensor networking is enabling technology for pervasive/ubiquitous computing Wireless sensor networking is enabling technology for pervasive/ubiquitous computing Middleware deals with the heterogeneity of the mobile devices. Middleware deals with the heterogeneity of the mobile devices. Who should be responsible for adaptation Who should be responsible for adaptation system or application?system or application? Application transparent or application aware?Application transparent or application aware?

14. Application Transparent Transparency – the ability of system to hide some characteristics of underlying implementation from users. Transparency – the ability of system to hide some characteristics of underlying implementation from users. Access transparencyAccess transparency Location transparencyLocation transparency Failure transparencyFailure transparency Application works with no modification in mobile environment Application works with no modification in mobile environment Proxy can be provided to hide the differences between the stationary and mobile environment from applications. Proxy can be provided to hide the differences between the stationary and mobile environment from applications. Adaptive system is responsible for adaptation Adaptive system is responsible for adaptation

15. Application-Aware Adaptation Adaptive system is responsible for adaptation Adaptive system is responsible for adaptation Does application-transparent way of adaptation suffice in mobile computing?Does application-transparent way of adaptation suffice in mobile computing? Performance issue, difficult for system adaptive to different applications, manual intervention may be neededPerformance issue, difficult for system adaptive to different applications, manual intervention may be needed Allows Applications to react to mobile resource changes Allows Applications to react to mobile resource changes How? How? Collaboration between System and individual ApplicationsCollaboration between System and individual Applications System monitors resource levels and notifies applications of relevant changesSystem monitors resource levels and notifies applications of relevant changes Application then adapts to the changeApplication then adapts to the change

16. Application-Aware Adaptation Multimedia Application Multimedia Application ApplicationsApplications Video Conferencing on mobile devices Video Conferencing on mobile devices Watch live video from Remote server on mobile devices Watch live video from Remote server on mobile devices Operating condition changesOperating condition changes Move/bandwidth changes Move/bandwidth changes Request other peer/serverRequest other peer/server Lower quality videoLower quality video Battery power level changes Battery power level changes Conserve energyConserve energy Reducing the intensity of the back light (display)Reducing the intensity of the back light (display)

17. Mechanism for Adaptation Mechanisms for adaptation Mechanisms for adaptation Adapting Functionality of Mobile ApplicationAdapting Functionality of Mobile Application Adapting Data – deliveredAdapting Data – delivered Adapting Functionality Adapting Functionality Classic client-server systems assumeClassic client-server systems assume location of client and server hosts do not change location of client and server hosts do not change connection among them does not change connection among them does not change Functionality between client and server is statically partitionedFunctionality between client and server is statically partitioned Varying the Partition of duties in Client-Server model in mobile computingVarying the Partition of duties in Client-Server model in mobile computing Connected - Client-Server (CS) model Connected - Client-Server (CS) model Disconnected – Mobile client works autonomously Disconnected – Mobile client works autonomously

18. Adapting Functionality Change dynamically the functionality of the computational entities Change dynamically the functionality of the computational entities Client/Server Client/Server Resource-poor mobile client requests a resource-rich server to perform expensive computationResource-poor mobile client requests a resource-rich server to perform expensive computation Request-Response modelRequest-Response model Services Services Web pages ← Web serversWeb pages ← Web servers Database serverDatabase server Temporary IP addressesTemporary IP addresses Name translationName translation

19. Adapting Functionality Extended Client/Server Extended Client/Server Maintain the state of the clients: hard state, soft stateMaintain the state of the clients: hard state, soft state Soft stateSoft state Updated periodically to avoid automatic deletion Updated periodically to avoid automatic deletion Useful in systems with dynamic configurations Useful in systems with dynamic configurations Soft state used inSoft state used in Resource Reservation Protocol (RSVP, RFC 4604, 4605) Resource Reservation Protocol (RSVP, RFC 4604, 4605) Internet Group Management Protocol (IGMP) Internet Group Management Protocol (IGMP) Request service → Sleep (conserve energy) → Wake up (get result)Request service → Sleep (conserve energy) → Wake up (get result)

20. Adapting Data Varying the quality of data (fidelity) Varying the quality of data (fidelity) Quality of Service (QoS) requirements in information access application Quality of Service (QoS) requirements in information access application Information qualityInformation quality PerformancePerformance Latency: from the Mobile client’s perspective Latency: from the Mobile client’s perspective Throughput: from the system’s perspective Throughput: from the system’s perspective Data maintained at remote server Data maintained at remote server Reference copyReference copy Complete and Up-to-dateComplete and Up-to-date Mobile client – may choose to access or manipulate data item of lower fidelity Mobile client – may choose to access or manipulate data item of lower fidelity

21. Adapting Data Fidelity Fidelity Agility Agility Speed and accuracy with which the application detects and responds to changesSpeed and accuracy with which the application detects and responds to changes Consistency Consistency Data quality Data quality Video data – frame rate and image qualityVideo data – frame rate and image quality Telemetry data – sampling rate and timelinessTelemetry data – sampling rate and timeliness

22. Adaptations How To Adaptive to detectable changes in their environment Adaptive to detectable changes in their environment Software detects changes Software detects changes Middleware layers or Operating systemMiddleware layers or Operating system E.g., TCP protocolE.g., TCP protocol State-based approach State-based approach Changes in mobile computing are viewed as State Transitions (e.g., Coda)Changes in mobile computing are viewed as State Transitions (e.g., Coda) Strongly connected Strongly connected Weak connectivity Weak connectivity Weak connectivity/Disconnected → Strong connectivity Weak connectivity/Disconnected → Strong connectivity Disconnected Disconnected Adaptation of function and/or data performed when a state transition occurs.Adaptation of function and/or data performed when a state transition occurs.

23. Where ? Adaptations Client /Proxy/Server Client /Proxy/Server Adapting to the hardware/software capabilities – in the proxy and/or at the server Adapting to the hardware/software capabilities – in the proxy and/or at the server Adapting to the connectivity of the mobile device: at the server and/or the client Adapting to the connectivity of the mobile device: at the server and/or the client Adapting to the resource availability at the mobile device: at the client Adapting to the resource availability at the mobile device: at the client

24. Where ? Adaptations Proxies: Proxies: Filtering data and connections (security firewalls)Filtering data and connections (security firewalls) Modifying control data (network address translator)Modifying control data (network address translator) Transcoding (converting data, content transformation)Transcoding (converting data, content transformation) Proxy reduces Bandwidth demands and allow legacy and non standard client to communicate with the server Proxy reduces Bandwidth demands and allow legacy and non standard client to communicate with the server