Modelling Feature Interaction Patterns in Nokia Mobile Phones

Modelling Feature Interaction Patterns in Nokia Mobile Phones using

Coloured Petri Nets and Design/CPN

Louise LorentsenUniversity of Aarhus

Antti-Pekka Tuovinen

Jianli XuNokia Research Center

29. august 2001CPN'012

MAFIA project Modelling and Analysis of Feature Interactions in mobile phone Architectures

Joint project– CPN group, University of Aarhus, Denmark– Nokia Research Center, Finland

15 man months Started nov.2000 Project group:

– Nokia: 2 part time– CPN: 3 part time, 1 full time


Design of a mobile phone UI

Special purpose device for personal communication and information management

Constrained device The user interface is designed to

support the most frequent and important user tasks

The links that enable this kind of flexibility must be built into the UI software


Features

Utility functions (the main purposes of the product) voice and data calls, messaging, phonebook, calendar, games, WAP browser, alarm

clock, calculator, ... user need: communications, time management, contact information management,

being entertained, being informed, … Settings (mode)

call forwarding, call barring, call diverting, profiles, caller groups, ringing tones… user need: configuration of utility functions according to the changing context of

usage, personalization

Notes battery low, charging, missed calls, … user need: getting informed about imporant events related to the (mechanical) state

of the device and the state of (asynchronous) utility functions

UI control functions any key answer, keyguard, keypad cover, lights, … user need: control and configure the user interaction with the device


Feature Interactions

A feature may– invoke other features

utility functions may need other utilities or their subfunctions functions need to issue warnings and info notes goal: smooth flow of users tasks

– take over the display and softkeys from other active feature(s) sharing limited resources according to the priorities of the usage

of the product

– affect the way other features behave configuration of utility functions controlling user interaction


Other issues

Concurrency user, network (calls & messaging), power management,

alarm clock, calendar alarms, SIM card

Very complex behavioral view from the SW development viewpoint!

Many design constraints Limited screen, keys, memory, processing power, …


Motivation for MAFIA

The types and number of interactions are direct indicators of the cost of developing the feature

Problems often arise when integrating independently developed featues

Features are documented (appearance and behavior) Feature interactions are not systematically documented It’s hard to get the interactions right in the

implementation!


Reality of UI Software Development?

UI design

analysis

SW design

Integration and

testing

implementation

and testing

design docs

?

UI specs

code


MAFIA Goals

Increase the level of understanding of the role that interactions play in the UI software and its development

– Many software developers have experience only in desktop applications

How?

1. Identify patterns of interactions that are specific to Nokia’s mobile phone UI

2. Create CPN models that capture the typical interaction patterns in each category

3. Provide 1. Static documentation that explains the interaction patterns

2. An environment for interactive exploration and simulation of the models for demonstrational or analytical purposes

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MAFIA Approach

Build a CPN model of the UI software system– The model reflects the existing UI architecture

(Applications, Servers, UI Controller, Communication kernel)– Features are modelled at a level that captures their essential

behavior– Generic sub-models for features– Modelling of the UI controller is a central issue – new features

can be plugged in

The model includes a sufficient number of features so that all the identified feature interaction categories are covered

29. august 2001CPN'0111

Software Architecture View

Applications implement the features of the mobile phone– Applications make the feature available to the user via a user interface

User interfaces are handled by the UI Controller Servers provide the basic capabilities for the applications

– Servers do not have user interfaces Communication by means of asynchronous message passing

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Overview of the CPN model

Hierarchically structured

4 parts– Applications– Servers– UI Controller– Communication

kernel

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UI controller I

Applications make the features available to the user via an user interface

1 2

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UI Controller II

Many applications active at the same time

Need to share the limited UI resources

1 2

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Game Feature

GAME(none)GAME(none)


GAME(suspended)GAME(suspended)

GAME(saved)GAME(saved)

GAME(active)GAME(active)


GAME(active)GAME(active)

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Common Send-Receive Pattern

Triggered by some action

Request for display Wait until display is

granted Proceed

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Incoming Call Feature

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Incoming Call Feature II

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General Send-Receive Pattern

Triggered by some action

Request server/application/UI controller

Wait for result Proceed

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Feature Modelling

User interfaces are handled by the UI controller Feature model:

– -"Top-level" model of the feature– -Description of UI requirements / use of servers or

other features

No assumptions about other features

Easy to add new features

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CPN model in Feature Development

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Mimic Library

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Message Sequence Charts Library

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Status - Future work - Conclusions

Status:– Categorisation of feature interactions– CPN model has several key features

MAFIA work has influenced the current development of a new feature (FM Radio)

MAFIA has generated ideas for the new UI software design