overview of mobile computing (2): applications and services

Overview of Mobile Computing (2): Applications and Services

The iMode Story: It is About Services!

• 27M Internet-capable cell phone sub-scribers (10/01); 50K iMode Web Sites

• World’s largest ISP, first to deploy 3G“Freedom of Multimedia Access” (FOMA)

• Not just about Japanese teenagers

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Applications Used User Ages

Economist Magazine, 13 Oct 2001

In the post-PC age…

• Not just about gadgets or access technologies• About services and applications, and how the

network can best support them• Increasing, not decreasing, diversity• Bottlenecks moving from core towards edge• Enabled by computing embedded in communications

fabric: wide-area, topology-aware, distributed computing

Services for Mobile Networks

How to build services for end users in a mobile and wireless networking environment:

• Issues and service types

• One example: universal interactor,

Grand Goal of “AAA” Mobile Services

AAA Service: “Any time, Any where, Any form” service

• Any time: it is about wireless (time-domain quality)

• Any where: it is about mobility (space-domain quality)

• Any form: it is about device diversity (systems quality)

Issues in building mobile services

• Mobility induced issues:– Seamless services: service migration– Location services: location itself is a service

• Heterogeneity induced issues:– Hardware diversity

• Client devices & different networks

– Software diversity• System software: OS, networking protocols• Application software

• Wireless induced issues:– Time-varying network connectivity: disconnection,

partial connection, full connection

Possible services types1. Location service

2. Location-transparent services– Hide locations from users: same as old Internet

3. Location-dependent services– Services “local” to a geographic location

– Not available globally

4. Location-aware services– Services are globally available, but multiple

instantiations of the same service are a function of locations

– Service adapts to a location

How to Provide Location Services• GPS at every node

• GPS at a few reference points– Build recursive location services through

reference hierarchy

• Geometric triangle computation– Cricket system

• Identify the current cell

• What about location tracking?

Services• Location transparent services:

– If lower-layer provides mobility support, this is not a big issue

• Location-dependent services:• Local currency exchange when visiting foreign

country• Location aware services:

– example: finding a nearby bookstore while driving

– Issue: service migration from old server to the new server

– Solution: location-adaptive

Building context-aware applications?

• Context is a key factor for mobile computing– Typical context: time, location coordinate, personal

profile, etc.

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Typically: Identity, location, time•Rest is implied•Not much else used: activity, mood, etc.

Design Process Using Tools?

For your information only

Not required for the exam

overview of mobile computing (2): applications and services

Documents

services slide

location slide

connection slide

exam slide

locationadaptive slide

distributed computing

location services gps

locationtransparent