TAXONOMY FOR MOBILE TERMINALS

A Selective Classification Scheme

Gunther Schiefer and Michael Decker

Institute of Applied Informatics and Formal Description Method, University Karlsruhe (TH), 76128 Karlsruhe, Germany

Keywords: Simple Phone, Feature Phone, Smartphone, Handheld, Web-Tablet, Netbook, Mobile PC, Tablet-PC,

classification, mobile Terminal.

Abstract: There is a great number of different types of mobile computing devices like cellular phones, Handhelds and

notebooks. However in literature so far there is no common accepted definition for these terminal types. Es-

pecially the term “Smartphone” is used for very different types of mobile phones. In our article we therefore

propose a comprehensive taxonomy for mobile terminals that clearly distinguishes between different classes

of terminals.

1 MOBILE TERMINALS

Everyday life without mobile terminals is almost

unthinkable. With the increasing use of them for a

multiplicity of tasks the equipment variants increase

likewise. At present the most popular mobile termi-

nals with the highest penetrations rates are mobile

phones and Feature Phones. According to Kuhn

(Kuhn, 2004) a mobile terminal is a portable com-

puter-assisted communication system with inde-

pendent data processing capacity, which can com-

municate as endpoint of a wireless connection with

other IT-systems. “Independent data processing

capacity” means that the mobile terminal is equipped

with random access memory (RAM), a central proc-

essing unit (CPU) (this implies programmability),

own network-independent power supply (battery)

and the possibility to directly interact with human

users by providing means for data input (e.g. keys,

microphone, touchscreen) as well data output (e.g.

display, light emitting diodes, speaker). Thus radio

frequency identity tags (RFID), Smartcard etc. are

not mobile terminals in the sense of the above defi-

nition because they don’t dispose over an independ-

ent power supply and a user interface. Computers

integrated into machines (e.g. vending machines,

machines in factories) are also not considered as

mobile terminals because a human user can’t carry

them along.

Mobile terminals differ particularly with regard

to their size, their use and their performance for the

execution of mobile applications. One reason for this

is that mobile computing is a rather new technology

so a market consolidation like that for personal desk-

top computers didn't take place yet. There are also

many application scenarios for mobile computers

with different requirements so it is necessary to have

mobile terminals especially developed for individual

fields of applications. To get an impression of the

great variety of mobile terminals one can refer to the

WURFL

project which assembles a profile database

with information about capabilities of different mo-

bile terminals: the file comprehends over 5.000

different profiles. Some software products for mo-

bile terminals are available in customized versions

for several hundred types of mobile terminals, e.g.

“Yahoo!Go”

a mobile applications that provides

access to services like e-mail, news, weather fore-

casts and maps.

Nevertheless we can identify distinct classes of

mobile terminals with common characteristics.

2 CLASSES OF TERMINALS

Within the range of the mobile terminals there are a

number of different types. They differ in the charac-

teristics listed above. There are different approaches

to divide the terminals into different classes (see for

example (Noesekabel and Lehner, 2002), (Meier,

2002) or (Roth, 2005)). The borders between the

http://wurfl.sourceforge.net/

http://mobile.yahoo.com/go

255

Schiefer G. and Decker M. (2008).

TAXONOMY FOR MOBILE TERMINALS - A Selective Classiﬁcation Scheme.

In Proceedings of the International Conference on e-Business, pages 255-258

DOI: 10.5220/0001911502550258

 SciTePress

different terminal classes are seen differently by

different authors and are often not clear. For exam-

ple according to Brome and Zeman (Brome and

Zeman, 2008) and Canalys (Canalys.com, 2004) the

classification into Feature Phone and Smartphone is

determined by whether additional software is exe-

cuted directly by the operating system or by a run-

time environment like Java ME. On the one hand

this distinction isn’t obvious, on the other hand there

are terminals which can do both.

Mobile terminals can differ in the following cri-

teria (list is not complete):

• Size and weight

• Input modes

• Output modes

• Performance

• Kind of usage

• Communication capabilities

• Type of operating system

• Expandability

Some of these characteristics can be used to dis-

tinguish classes of terminals from each other. The

following section gives criteria for the classification

of mobile terminals into distinct classes without the

need to do a deepened technical analysis. All classes

regarded in our classification (see also Figure 1)

have the ability for bidirectional wireless communi-

cation and have an independent power in the form of

an accumulator. Hereby the often vague defined

term Smartphone will be clearly separated from

Feature Phone and Handheld.

2.1 Mobile Standard PC

The wireless mobile standard computers include

laptops/notebooks, subnotebooks (also called net-

books) and Tablet-PC (including ultra mobile PC

(UMPC)). Subnotebook is the name for a particu-

larly small and light notebook, whose equipment is

very similar to those in a full notebook, however has

no optical drives (CD/DVD-ROM-drive) and a

smaller keyboard. An UMPC is a Tablet-PC which

is maximally 8 inches large, weighs maximally

900 grams and has a display with a resolution of at

least 800x480 pixels; Keyboards can be attached

externally. On these terminals the conventional

desktop operating systems (Linux, Windows) can be

used as well as the compatible software packages

like office suites. Substantial distinguishing features

are the size of chassis and display, the weight, the

Figure 1: Classification tree of mobile terminals.

Mobile terminals

In narrow sense In broad sense

Wireless mobile

Computer

Smartcards

Board-

computer

Feature

Phones

Handhelds

Mobile Internet

Devices

Mobile

Standard PC

Tablet-PC

Smart

Phones

Mobile phones

Simple

Phones

Subnotebooks

ICE-B 2008 - International Conference on e-Business

256

integrated peripherals (e.g. optical Drive included)

and the operation kind of the terminals.

Notebooks with wireless communication capa-

bilities are mobile terminals according to definition

given above. However in the following considera-

tions we won’t focus on them because our article is

more concerned with smaller and lighter terminals

that can be used by a walking or standing user.

Notebooks usually need a „stand space“ like a table

or someone’s lap. Tablet PCs on the other hand are a

special subclass of the mobile standard computers,

because they have a touch-sensitive display and

therefore can be used while standing with only one

hand so they can be operated without a stand space.

2.2 Mobile Internet Devices

Beside the mobile standard PC there is a terminal

class “Mobile Internet Devices” (MID) (also called

Web-Tablet or mobile Thin Client) with similar

equipment and display size, however clearly reduced

function range and normally no mechanical drives.

Characteristically these terminals are equipped like

Handhelds (see below) with an operating system in

the read-only memory (ROM) and are immediately

ready for use after switching them on. Their function

range is similar to the Handhelds and they are

mainly used for browsing the web and as client for

terminal server sessions. They depend mostly on a

constant wireless network connection for the fulfil-

ment of their tasks. The Web-Tablets (like the Tablet

PC) can be operated through a touch-sensitive dis-

play, the mobile Thin Clients usually through a

keyboard.

2.3 Handhelds

Handhelds are small computers, which — like the

name already suggest — can be held in one hand.

They are called often also Personal Digital Assistant

(PDA). Historically these were originated from the

pure organizers, which could be predominantly used

for personal information management (PIM) appli-

cations like calendar, address book or personal

notes. Today's Handhelds have clearly higher per-

formance and are usually equipped with multimedia

capabilities. As written above, only Handhelds who

are able to establish a wireless connection are re-

garded here. They are equipped usually with an

operating system in the ROM and are immediately

ready for use after switching on (no boot-time

needed). Apart from the pre-installed programs in

the ROM, users can install further applications in the

RAM or the flash memory and attach various exten-

sion modules. Handhelds usually have a touch-

sensitive display and can be used with a pen (or the

fingers), or they have a text keyboard and navigation

keys for it. Increasingly there are terminals which

can be operated through both of them. Terminals are

only classified as Handheld if they cannot communi-

cate in communication networks for mobile teleph-

ony like GSM or UMTS.

2.4 Smartphones

The term “Smartphone” designates a combination of

Feature Phone (see below) and Handheld with usu-

ally somewhat smaller dimensions, smaller display

and partly reduced function range in comparison to

the Handheld. They form their own class. On the one

hand mobile computers which have the characteris-

tics of Handhelds and the ability to communication

over mobile telephony networks and have almost

everywhere and „seamless“

connection to the Inter-

net belong to this class. On the other hand portable

radio terminals with the characteristics of Feature

Phones that have extended input modes belong to

this class, too. The extended input mode can be

provided by a touch-sensitive display (which can be

used with the fingers or a pen) or a complete text

keyboard.

2.5 Feature Phones

Feature Phones are mobile phones (see below) with

usually somewhat larger display and extended func-

tion range. The primary use purpose of the Feature

Phones lies in mobile communication, which in-

cludes both the voice communication and text-based

communication (SMS, MMS, e-mail etc.). For this

terminal class the ability for wireless data communi-

cation over the mobile communications networks

(e.g. GPRS or UMTS) and the absence of the ex-

tended input modes are characteristic. These are

limited to a number keyboard and a few additional

keys. Particularly terminals which support not only

the GSM standard but also UMTS are equipped with

a Web browser and software to play back multime-

dia contents. On these terminals the user can install

additional software. Since many terminals have

proprietary operating systems, in most cases addi-

tional software is offered on basis of Java Micro

Seamless means that these terminals change unno-

ticed and without further user interaction inde-

pendently from one radio cell to another (soft

handover) and give the user the impression of only

one large radio cell.

TAXONOMY FOR MOBILE TERMINALS - A Selective Classification Scheme

257

Edition (Java ME), which is supported by nearly

every Feature Phone manufactured today.

2.6 Simple Phones

The classical mobile phones (also termed “cellular

phone”) were developed primarily for mere voice

communication. However nowadays text-based

communication in the form of the short message

service (SMS) is a standard feature of mobile

phones. For Simple Phones it is characteristic that

they are not able to use wireless data communication

based on TCP/IP (e.g. browsing the internet or re-

ceive e-mail). The resolution and colour depth pro-

vided by displays of these terminals was signifi-

cantly improved in the recent years. The displays

became also bigger but they are usually noticeably

smaller than those of Feature Phones. The function

range of these terminals can only be extended with

software in a small scale, e.g. by additional ring-

tones, pictures and multimedia animations or games,

whereby these are strongly limited by the memory

free space and the performance of the processor.

2.7 Special Terminals

Beyond the versatile usable standard terminals there

are a number of specialized mobile terminals which

cannot be arranged into the above classification.

These are for example e-book readers for storage

and reproduction of electronic books, electronic light

pens, which can read bar code or printed texts and

process electronically or bar code readers with num-

ber keyboard for the stocktaking in supermarkets: A

worker scans the product code, enters the number of

available products in shelf and transfers all immedi-

ately wirelessly to a server.

Navigation terminals for travellers became quite

popular in the last few years. Those terminals can be

used for locating as well as for route guidance.

These terminals can calculate their own position

based on the signals received from several satellites

(Küpper, 2005). The global positioning system

(GPS) of the US military or the Russian system

GLONASS are already in use for many years and

can be used nearly world-wide without fees. The

projected Galileo system by the European Union is a

civilian system that will provide some service for

navigation free of charge; the full operation of this

system is now scheduled to start in the year 2013.

GPS (ore others) receivers can be integrated into a

mobile terminal but there are also separate GPS

modules (so called “GPS mouse”) that can be con-

nected to a mobile terminal using a cable or blue-

tooth.

3 CONCLUSIONS

In this article we distinguished the mobile terminals

clearly from other mobile devices. With the intro-

duction of the term Feature Phone, which is used

rarely by other authors, mobile phones can be di-

vided selectively into different classes. The term

Smartphone, which was until then fuzzy, become

consequently clear. With the introduction of the

class of special terminals, which comprehends all

terminals for special tasks that cannot and should not

be assigned to the standard classes, the classification

of mobile terminals is altogether clear and complete.

ACKNOWLEDGEMENTS

This work has been funded by the Federal Ministry

of Economics and Technology, Germany (BMWi,

Contract No. 01MD06012). The responsibility for

the content of this article lies solely with the authors.

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