Modelling Feature Interaction Patterns in Nokia Mobile Phones using Coloured Petri Nets and Design/CPN Louise Lorentsen University of Aarhus Antti-Pekka Tuovinen Jianli Xu Nokia Research Center

29. august 2001 CPN'01 2 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

29. august 2001 CPN'01 3 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

29. august 2001 CPN'01 4 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

29. august 2001 CPN'01 5 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

29. august 2001 CPN'01 6 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, …

29. august 2001 CPN'01 7 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!

29. august 2001 CPN'01 8 Reality of UI Software Development? UI design analysis SW design Integrat ion and testing implemen tation and testing design docs ? UI specs code

29. august 2001 CPN'01 9 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

29. august 2001 CPN'01 10 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 2001 CPN'01 11 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

29. august 2001 CPN'01 12 Overview of the CPN model Hierarchically structured 4 parts – Applications – Servers – UI Controller – Communication kernel

29. august 2001 CPN'01 13 UI controller I Applications make the features available to the user via an user interface 12

29. august 2001 CPN'01 14 UI Controller II Many applications active at the same time Need to share the limited UI resources 1 2

29. august 2001 CPN'01 15 Game FeatureGAME(none) GAME(none) GAME(suspended) GAME(saved) GAME(active) GAME(none) GAME(active)

29. august 2001 CPN'01 16 Common Send-Receive Pattern Triggered by some action Request for display Wait until display is granted Proceed

29. august 2001 CPN'01 17 Incoming Call Feature

29. august 2001 CPN'01 18 Incoming Call Feature II

29. august 2001 CPN'01 19 General Send-Receive Pattern Triggered by some action Request server/application/UI controller Wait for result Proceed

29. august 2001 CPN'01 20 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

29. august 2001 CPN'01 21 CPN model in Feature Development

29. august 2001 CPN'01 22 Mimic Library

29. august 2001 CPN'01 23 Message Sequence Charts Library

29. august 2001 CPN'01 24 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