chat on a phone, not a pc clone: ims-based mobile community service

Ericsson Review No. 1, 200814

Introduction

Today’s young people are surrounded by communication technologies that have a central place in their daily lives, such as the internet and mobile phones.1 Text messaging (short message service, SMS), for example, became a fully established phenomenon by the late 1990s. And teens were especially quick to adopt it. Today, SMS is the second most used mobile phone service (after voice) in Europe and in parts of Asia.2 At the same time, instant messaging (IM) has emerged as a favorite tool for online communication. This is because IM enables users to exchange messages in real time. People today employ IM to maintain existing friendships, enhance their social status, make new friends, and manage the demands of daily life.3-4

Compared with PC-based IM, the outlook for mobile-phone-based IM is less clear, since it is still a niche service, especially compared with SMS. Notwithstanding, PC-based IM

service providers, such as Yahoo! and Micro-soft MSN, are taking measures to expand into the mobile domain, in order to attain a prom-inent position in the mobile IM market.

In 2006, Ericsson Research developed and implemented an IMS-based service proto-type for mobile communities. The service simultaneously supports IM, voice calls, live video sharing, and presence information. To optimize the user experience, Ericsson evalu-ated the concept using typical IM users; that is, teens and young adults.

IMS-based service conceptThe prototype service concept supports text (IM) and voice communication (VoIP). The voice and text channels handle one-to-one and group communication as well as paral-lel communication sessions. During one-to-one voice communication, users may share live, unidirectional video streams. The ser-vice even synchronizes presence status and free text information among all clients. The concept was implemented on Sony Ericsson Z800i and K800i phones (Figure 1).

Design conceptThe service concept was designed to give us-ers only two windows:

contact view; and communication view.

The contact view displays user contacts. Communication is initiated from the address book (Figure 1, “A”), which contains pres-ence information (Available/Not available) and free text about every contact. Users can change personal presence status and free text in the address book. When the information changes, it is automatically updated on all clients (local and remote).

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The communication view holds all active communication. Chat entries, communica-tion status, and the presence status of remote users are presented in this view (Figure 1, “B”). Each communication session is dis-played separately in a tabbed chat window.

Concept target segmentThe concept was developed to target teens and young adults. Experience has shown that these groups of users are usually the fi rst to integrate new data services into everyday communication and social life. They are ac-tive communicators (high frequency rate) and expect to be able to communicate with peers anywhere and at any time.5

Design process and methodThe service concept was developed using a user-centered design (UCD) process that takes an iterative approach to design, imple-mentation and evaluation. Three prototypes were developed during the project (Figure 2). The fi rst two were tested for usability and heuristics, and the third was tested on con-sumers from the target segment. The test results served as input to the different phases of the work process to further optimize the user experience.

The fi rst prototype was delivered on a Sony Ericsson Z800 with a limited feature set: one-to-one chat, VoIP calls, live video shar-ing, and stand-alone buddy list. The second prototype, which was delivered a few months later, added a chat history feature, presence information, and an enhanced design. The fi nal prototype ported the application to a Sony Ericsson K800i. In this iteration, the design had been updated yet again using the results of the second expert evaluation. The service now supported group chat and calls, and integrated the buddy list function into the address book. The implementation was also subsequently evaluated by end-users.

Preliminary studyThe initial design activity consisted of a study of areas relating to instant messaging, online communities, and the target user seg-ments. The study included reviews of reports from Ericsson, as well as commercial and academic sources. The study also conducted hands-on trials of different IM/communica-tion applications and services. All the project stakeholders took part in activities to defi ne a

Delivering a great user experience in the simplest possible way is often a complex task. To succeed, one must understand and translate user needs, expectations, technical opportunities, and constraints into an adequate design.

The authors describe the user-centered approach that was used to develop an IMS-based service for mobile communities. The service con-cept, which supports text (instant messaging, IM) and voice communica-tion (VoIP), uses the IMS core system, presence and group management (PGM), application servers (AS) and media resource function processors (MRFP). The authors also discuss key fi ndings from end-user studies and their pertinence to the project.

Chat on a phone, not a PC clone:IMS-based mobile community serviceDidier Chincholle, Michael Björn, Cristian Norlin and Morgan Lindqvist

TERMS AND ABBREVIATIONS

3GPP Third Generation Partnership

Project

AS Application server

GUI Graphical user interface

GSM-AMR Voice codec used in mobile

networks

IM Instant messaging

IMS IP Multimedia Subsystem

MRFP Media resource function

processor

MSRP Message session relay protocol

PC Personal computer

PGM Presence and group

management

RTP Real-time transport protocol

SIP Session initiation protocol

SMS Short message service

UCD User-centered design

VoIP Voice over internet protocol

Review108.indd 14Review108.indd 14 08-01-21 16.08.3108-01-21 16.08.31

Ericsson Review No. 1, 2008 15

broad but relevant scope for the study. Their experiences and fi ndings were then discussed and analyzed in a series of workshops.

ScenariosWith the target segment of the service con-cept in mind, the project defi ned a number of simple personas (see example in Figure 3) that served as the main characters in several text-based communication scenarios. The associated tasks were used to communicate ideas and concepts to project participants and stakeholders. The number of concepts that were developed into scenarios (see ex-ample in Figure 4) exceeded the number of features in the fi nal design, in part because some concepts had been discarded during the iterative development process.

Use casesThe scenarios were next translated into use cases that describe interaction between per-sonas/users and a given service. The use cases gave participants in the project simple descrip-tions of the key features of the service and ap-plications. Stakeholders discussed and modi-fi ed the use cases in workshops held to reach agreement regarding the solutions around which the concept was to be designed.

Interaction and GUI designInitially, all interaction was designed on paper in the form of wireframes of screen layouts and graphical elements. This exer-cise showed the principal fl ows of interac-tion, navigation models, appearance, and behavior for different service/application states. The interaction fl ows were annotat-ed with comments to clarify behavior and conditions and to describe sounds, anima-tions and tactile feedback. The interaction wireframes were discussed extensively and reworked several times throughout the de-velopment process.

The graphical user interface (GUI) was developed at the same time. Sketches of the GUI were introduced to the development team as a complement to the wireframes, allowing for a dynamic discussion about in-teraction, behavior and appearance. In short, the project groups interacted with one an-other, exchanging their fi ndings rapidly and iteratively with all project stakeholders.

Iterative process with expert evaluationsBy design, the development process was meant to result in the delivery of three major

prototypes: two work-in-progress prototypes and one fi nal prototype. A group of experts (Figure 5) tested and analyzed the fi rst two prototypes relative to commonly accepted usability principles and heuristics.6-7 This procedure was similar to, but less formal than, the heuristic evaluations.8 Feedback from each evaluation was input into the work on the next prototype. The fi nal prototype was then tested on “real” end-users.

User studies

Qualitative research was conducted in November 2006 in Stockholm, Sweden. Seventy-fi ve people (men and women aged 15-25) were recruited to participate in nine focus groups emphasizing current IM-re-lated services and technologies on PCs and mobile phones.

Respondents were recruited as pairs of

Figure 1(A) Contact view and (B) communication views.

Figure 2User-centered approach to designing the IMS-based service.



friends and screened for daily communica-tion via voice and SMS on mobile phones, use of IM on PCs, and broadband access at home.

From the focus groups, nine pairs of friends were selected for a usability evalu-ation of the service prototype client. And fi nally, in-depth interviews were conducted with the same nine pairs of participants (Fig-ure 6). The aim of the research was

to obtain feedback on usability issues and the performance requirements of the ser-

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vice concept on mobile phones; and to better understand consumer drivers and barriers related to communication via PCs and mobile phones.

Key fi ndingsPCs and mobile phones are essential parts of everyday life. We use them to stay connected with friends and peer groups. Notwithstand-ing, PCs and mobile phones are typically used in different contexts. Mobile phones are used when users are on the move and face

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a variety of potential distractions that could cause them to lose focus. PCs, on the other hand, are primarily used at home (even lap-top models). And although users frequently multitask (for instance, by communicating with several people at once through IM) they are generally in far greater control of the communication context and can therefore re-main more focused.9-10

PC messaging behavior

PC users perceived Microsoft MSN Messen-ger to be virtually synonymous with instant messaging. The features that respondents consider valuable for structuring and con-trolling communication are primarily

free text to express moods; offl ine/busy modes to facilitate privacy and selectivity when communicating; and fi le sharing – media often provides topics for conversation.

The typical messaging behavior on a PC is to have up to four or fi ve parallel one-on-one sessions open alongside one another. Con-tacts are often categorized in groups, such as school, friends and others.

Mobile messaging behavior

Mobile phone messaging primarily involves one’s immediate network of contacts – typi-cally between six and eight friends or family members. Messages are generally exchanged on a one-to-one basis. SMS is frequently used in a chat-like manner with messages being sent back and forth rapidly to keep a dialog going.

When asked about chat services (such as mobile MSN), respondents showed little spontaneous interest. Their response was that MSN-like chatting with a mobile phone seemed too complicated. Moreover, they were reluctant to merge MSN contacts into the native address book on their phones.

Usability evaluation and in-depth interviewsDespite low initial interest for MSN-like chatting using a mobile phone, the response to the service prototype during usability testing and in-depth interviews was much more positive.

For many, the turning point came when they realized that the service prototype was not, in fact, downgraded MSN on the phone but rather a complement to SMS. Once they had made this mental transition, respondents asked for some of the key functional elements of MSN in the service prototype.

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Figure 3Eva, a persona from the IMS-based service study.

Eva, 20, is a student at the Umeå Institute of Design. She is active in many areas: clubs, university and sports. She enjoys sharing experiences with friends and spends little time at home. She wants to spend as much of her free time as possible socializing. She uses PC and mobile messaging services quite heavily to maintain her social network. She uses her small, fashionable mobile phone mainly for calling, texting, taking pictures and listening to music. Having access to the information she needs is key.

Figure 4A persona-based scenario from the IMS-based service study.

From text to voice… London, 9 pm While waiting for her boyfriend, Alice checks to see if any of her friends are online (she checks the address book in her mobile phone for “active addresses”). Eva is online and available so she invites her to join her in a chat session. Eva accepts and they begin chatting about vacation plans. When the conversation becomes too detailed and diffi cult for simple texting, Alice suggests that they switch to voice mode. Eva agrees and they continue their conversation...


Ericsson Review No. 1, 2008 17

Usability evaluationRespondents perceived the service prototype to be straightforward and intuitive, albeit with some minor usability issues, which in-cluded

features that needed to be given more prominence in the interface (presence, free text, one-to-one calls and chat); and functional improvements (ability to save chat dialogs and front/rear camera alterna-tives for live video).

In-depth interviewsMSN on a PC is used for communication in an extended network, but mobile phones are primarily used for an immediate network of typically fewer than ten contacts. Users gen-erally wanted to retain MSN as their primary tool for chatting on the computer, but wel-comed the IMS-based service prototype as a new option for communicating with con-tacts already present in their phone’s address book.

As with MSN on a PC, users wanted to have control over incoming communication when using the IMS-based service prototype. For instance, they wanted to be able to hide from others but still have the option to com-municate. And as with MSN, the ability to share fi les added value to the communication experience.

Respondents preferred to keep the phone and PC separate, because they contain differ-ent types of contacts that are used in differ-ent situations and for different purposes. By keeping their devices (and services) separate, respondents felt they could better structure their contacts and communication activities.

Use of IMS and protocols

The client in the prototype employs IMS to enable a host of functions. IMS is a 3GPP specifi cation based on session initiation pro-tocol (SIP) signaling. When a mobile phone is turned on, its IMS client registers it with the IMS core system, which enables the phone to receive incoming presence informa-tion, chat messages, and voice calls without the need for user intervention. Headers in the registration message tell the IMS core system what kind of services the client can support. The client in the prototype supports chat and multimedia telephony. The IMS core system uses this information when it routes requests to clients. This way, clients that do not support a specifi c service will not receive a request to establish that service.

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When a user requests a chat session, the IMS core network establishes a message session relay protocol (MSRP) connection between the local and remote clients. This connection is used for transmitting chat mes-sages and feedback – for example, “X is typ-ing.” From the address book, one may mark several contacts to initiate a group chat ses-sion. In this case, MSRP connections are es-tablished between each client and an MRFP node in the IMS core network. The MRFP node sends all incoming messages to the oth-er clients in the group. The application server (AS) that controls the MRFP node notifi es all participants when a member has joined or left the group.

One may even have a voice session along-side a chat session. The voice is encoded (us-ing GSM-AMR) and transmitted in RTP packets. During a group voice session, the RTP voice packets are sent to an MRFP

node that distributes them to the appropri-ate clients.

Clients exchange presence information us-ing the PGM node in IMS. Each client pub-lishes its presence information to the PGM, which forwards it to clients that have per-mission (have been authorized) to receive this information.

Conclusion

We involved usability experts and end-users (from a well-defi ned target segment) early and iteratively in the design process. This helped us to translate the initial service con-cept into a design that was better suited to target users’ expectations. The iterative ap-proach also enabled other stakeholders such as software developers, system architects and managers to get more involved in the design process, thus better contributing to a valid

Figure 5Expert evaluation of the IMS-based service prototype.

BOX A, DEFINITIONS

FOCUS GROUP: Listen to the usersA focus group discussion is a qualitative method for obtaining in-depth information on concepts

and perceptions about a certain topic through spontaneous group discussion of approximately

6–12 persons, guided by a facilitator.

Ref: http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1871685

USABILITY EVALUATION: Observe the usersA usability evaluation is a means of measuring how well people can use human-made objects

(such as a web page, a computer interface, a document, or a device) for its intended purpose.

Ref: http://en.wikipedia.org/wiki/Usability_testing

IN-DEPTH INTERVIEW: Ask the usersAn in-depth interview is a face-to-face conversation to explore issues; it is conducted without

using a structured questionnaire.

Ref: http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1871685



and feasible design. Implementing an end-to-end concept using the IMS core was easier than expected. It was also simple to add both ASs and MRFPs to enable functionality not supported by the available IMS core.

The user study highlighted that end-user interest in converged communication servic-es should not be taken for granted. Although this communication culture may change in the future, young end-users currently struc-ture their communication patterns by divid-ing services rather than combining them (different contact lists for different social contexts, different services for different mes-sages, and so on). Ignorance of current com-munication cultures can introduce problems rather than provide user benefi ts.

Consequently, end-users do not particu-larly want a PC service which has been im-ported to the mobile phone. Instead, they perceived the IMS-based concept as a ser-vice optimized for the mobile phone and its unique functionality. More specifi cally, it can provide a set of tools for a community which has hitherto been overlooked – the imme-diate network of friends and family already present in the mobile phone address book.

For these reasons, the service concept can provide both rational and emotional benefi ts. On a rational level it can make communica-tion between contacts in the immediate net-work more effi cient. On an emotional level it adds a new quality of immediacy and in-timacy to mobile phone messaging. This in turn makes the mobile phone more relevant and fun to use. Figure 6

The three phases of the user study: (1) Focus group, (2) usability evaluation and (3) in-depth interview.

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chat on a phone, not a pc clone: ims-based mobile community service

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