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Wireless Services

Key questions

  1. What service do we want to create?
  2. For whom do we create the service?
  3. What kind of devices do they have?
  4. What are the devices communication capabilities?
  5. Do we need a client program for user device?
  6. What is our communication model?
  7. What is required from user & how can we help on it?
  8. What can we optimise in the service?

Communication models

  • Client server models
    1. Request-reply
    2. Push
    3. Publish-subscribe
  • Peer to peer communications

Request-reply

  • Client requests data & server provides the data requested
  • Most common model
  • Latency heavily affected

Push

  • Server sends data to client without requests
  • Can be intrusive
  • Who may push data to mobile devices?
    • Push validation, whitelists
    • OMA Push Proxy Gateway (OMA PPG)
  • Is the communication capability always on at user's device?
    • E.g. is Bluetooth communication capability turned on by default?

Publish-subscribe

  • Client subscribes itself to server
    • Whenever subscribed data in server changes it is pushed to the client
  • Advantages over request-reply
    • Reduced bandwidth requirements
      • Server App only sends data changes for a specific point to clients registered to exception on that point
    • Reduces latency problems
      • Client App no longer constantly asking for new data
      • Data not delayed by polling cycles

Publish-subscribe ...

  • How to handle subscriptions
    • Server side
      • Lost connection → unsubscribe?
      • Timers
    • Client side
      • Automated re-subcriptions
      • When to give up?
  • Retransmissions?
  • Limitations to amount of subscribees?
  • Allow anonymity to subscribers?
  • Presence based services

P2P

  • Communication Apps (devices) are equal
    • Either can initiate the connection
    • Data transmission can go in both ways
    • End-to-end security
    • How to handle differences in device capabilities
      • Division of calculation
  • ComLab - Peerhood project
    • P2P neighborhood
    • Provides information about devices & their Apps that are within communication range
    • Supports multiple communication technologies
    • Provides capability to switch between commmunication technologies seamlessly

Ad-hoc

  • Spontaneous temporary connections
  • All communicating devices can be mobile
    • App can not rely on connections remaining functional
  • Routing is problematic
  • Load balancing
    • Movement of nodes may cause extra burden to others

Client

  • Is there a need to create one?
    • Can the service be used with an existing application
      • E.g. microbrowser .. instant messaging client (imo)
  • UI
    • What kind of interaction has to be supported
    • How many hardware platforms have to be supported
  • Data storage
    • Do you need to store data at the device?
    • Can data be stored & how much space is available?

User aspects

  • Whats required from the user?
    • Creation of connection
      • Is the wireless connection creation simple enough?
    • Interaction with the service?
  • Transparent service
    • The service access & running does not require any user action
      • E.g. information walls
    • Where to draw the line on automation

User apsects ...

  • How can we help the user to use the service
    • personalisation
      • What is too much automation?
    • Configuration
      • Can the user know when the selections are done?
    • Context-Awareness
      • Location
      • Time
      • Role

Optimisation

  • What to optimise?
    • Minimise data transfer?
    • Minimise packet amount/payload?
    • Minimise client processor use?
    • Security Vs. usability
  • Selections depend on requirements of the service & the user

Wireless posibilities

  • Mobility
  • Presence & availability
    • Mobile device is most of the time with user
  • Location
    • Utilise user's location to customise the service
  • Context-Aware application

Architectures

Mobile Internet

  • Not just conventional web browsing
    • Browsing is cumbersome with mobile devices
  • Apps & services
    • Transactions
    • Connectivity to people
    • Games & entertainment
    • Sources of media content
    • Manage everyday events

Mobile Internet - Specifications

  • Architecture specifications
    • Permanent baseline of MITA
  • Key system specifications
    • end-to-end system aspects
  • Architecture frameworks
    • Define how to handle some special issues e.g. security & QoS

Mobile Internet - Architecture specification

  • UI & App framework
    • Guidelines for UIs
    • Limited set of UI styles
    • Mapping App functionality to physical UI in understandable way
    • Minimising customer learning curves to adopt new Apps & services
  • Interaction models
    • Messaging
    • Browsing
    • Rich Call

Messaging

  • Non real-time
  • Client-server based communication
  • Asynchronous
  • Server functionality
    • Store & forward (SMS, EMS, MMS)
    • Store & retrieve (EMAIL)
    • Store & push
    • Publish & subscribe

Browsing

  • Near real-time
  • Request-response
  • One-way audio & video streaming capability
  • XHTML mobile profile
  • Online & offline browsing

Rich call

  • Two-way real-time communication
  • QoS
    • Jitter (variation in time between packets arriving)
    • Latency
  • Voice & video calls
  • Concurent communication

Internet protocols in MITA

  • IP protocol extended to support mobility (mobile IP)
  • OS & platform support in MITA
  • Sets basic requirements for OS & platform
  • Defines required functionality
    • Libraries, APIs, network protocols, …
  • Does not define preferred OS just the required capabilities
  • Eases the portability of Apps
  • Multiple access in MITA
  • Defines the elements needed to allow access from mobile device to IP network
  • Access independent interface shields the mobile Internet layer from underlying technology

MITA - Key system specifications

  • Naming Numbering & Addressing (NNA)
  • Presence
  • Reachability
  • Location

Naming Numbering & Addressing

  • Identity/addressing
    • Phone number
    • www-address
    • E-mail address
  • Translation between different types of naming schemes on different communication types

Presence

  • Provides dynamic information about
    • The status & availability of users & mobile devices
  • One user may have multiple App level identities
    • Presence can be different for different Apps

Reachability

  • Defines how the user/device can be reached through web/mobile domain
  • Tries to solve the problem caused by different types of networks
  • Access independent connectivity
  • Mobility management
  • Reliability to end-to-end communications
  • Service discovery
  • Three types of methods
    • SD on ad-hoc networks
    • SD on Internet
    • SD for presence & virtual community

Location

  • Defines software & protocol interfaces for location services
  • Device management & data synchronisation
  • Distributed applications & databases
  • Link between presence & contact/calendar
  • Personal Information Management (PIM)
  • Content download
  • Content formats
  • Content adaptation
  • To support different types of devices
  • Privacy

Architecture frameworks

  • Defines how to handle some issues that are complicated to solve without a common & unified model
    • Structured under common framework before a more detailed architecture is built
  • Current frameworks include:
    1. Directories
    2. Security in MITA
    3. QoS

Directories

  • Network repositories about people, places & things
    1. Schema
    2. Access methods
    3. Directory store

Security

  1. Integrity
  2. Confidentiality
  3. Availability
  4. Authentication
  5. Authorisation

Mobile Internet interfaces

  • Open interfaces to software & protocols for software developers & integrators
  • Quality of service
    • Real-time, Near real-time, Async, ..
    • Jitter, latency, tolerable Delays, …

MITA ppt

Ubicomp & App areas

  • Ubiquitous computing - Mark Weiser (1952-1999), Xerox Parc 1988
    • Each person is continually interacting with hundreds of nearby interconnected computers without explicitly attending to them
    • Computers are integrated in everyday objects like motors.
      • people use the items not computers as much as you use a drill not the motor
    • The most profound technologies are those that dissapear. The weave themselves into the fabric of everyday life untill they are indistinguishable from it” - Weiser, The computer of the 21st century, scientific american, september 1991.
  • Pervasive computing - Academia, IBM 1999
    • Pervasive computing encompasses the dramtically expanding sphere of computers embedded within and instrinsically part of larger devices - IBM

Ubicomp & App areas ...

  • Ambient inteligence - European commision
    • People living easily in digital environments in which the electronics are sensitve to peoples needs, personalised to their requirements, anticipatory of their behaviour and responsive to their presence” - philips
    • Ambient inteligence repsents a vision of the future where we shall be surronded by electronic environmnets, sensitive and responsive to people. Ambient intelligence technologies are expected to combine concepts of ubiquitous computing & intelligent systems putting humans in the center of technological development” - 2nd European symposium on ambient intelligence
  • Calm computing - Weiser & John Seely Brown 1996
    • Computing activity takes place in the background & provides outcome in an unobtrusive way
    • Dangling strings, Laughing lily, …

Ubicomp & App areas ...

  • Active environments, augmented environments, augmented reality
  • Virtual reality takes place in digital world, augmented environments brings digital enhancements in normal environments
  • Augmenting humans
    • Adding capabilities to humans
    • Computing power is everywhere, because computer is embedded in the user
  • Awareness
    • Communication with environment
    • Knowledge of current situation
    • Knowledge of users

Challenges

  • User interfaces
    • Multi-modality
      • Modality–> way to convey information between a user & App interface using single distinct human capability to process the information
        • Text, graphics, speech, audio, …
      • UI adapted to the device capability
        • Speaker, graphical display, …?
        • Microphone, keyboards, …?
  • Connections
    • Machine to machine communications?
  • Automation
    • System control Vs. user control
    • Privacy Vs usability

Comlab & ubicomp Apps

  • Guidance systems
  • Mobile phone & bicycle communications
  • Automated locks & computer login
  • ME- Mobile Electronic Personality

References

  • Mobile Internet Technical Architecture book series, Nokia & IT Press
    • Technologies & standardisation
    • Solutions & tools
    • Visions & implementations
  • Ubiquitous computing
    • Magazines
      • Personal & ubiquitous computing magazine - springer verlag
      • IEEE pervaise computing magazine - IEEE
    • Books
      • Security for ubiquitous computing - Frank Stajano
      • Pervasive computing - Technology & architectures of mobile internet applications - Jochen Burkhardt et al.
      • World without secrets: Business, crime & privacy in the age of ubiquitous computing - Richard Hunter

References ...

Last modified: 2013/07/01 14:42