A BLUETOOTH BASED PROTOCOL FOR MULTIMEDIA
GUIDEBOOKS ON MOBILE COMPUTING DEVICES
Experiencing Mobile Locality-Aware Multimedia in the Palm of Your Hand
Matthew D’Souza, Adam Postula, Neil Bergmann
School of Information Technology and Electrical Engineering
The University of Queensland, Brisbane, Australia
Montserrat Ros
School of Mathematics, Statistics and Computer Science
The University of New England, Armidale, Australia
Keywords: Multimedia Guide Book, Bluetooth Wireless Network, On Demand Context-Aware Multimedia, Wireless
Communications Protocol.
Abstract: This paper presents a Bluetooth based communications protocol used for multimedia guidebooks on mobile
computing devices. Multimedia guidebooks are used in museums to allow users to access information about
museum exhibits. The multimedia guidebook protocol was successfully implemented on a personal digital
assistant and mobile (cell) phone platforms. The protocol overcomes some of the wireless file transfer
protocol limitation issues with mobile computing devices. The protocol uses Bluetooth wireless connections
as a communications medium. The protocol can be used to transfer various file formats such as image or
audio files. The protocol also identifies the language content of the information file. Future work on this
protocol involves expanding it to allow for other languages to be included and other user preferences such
as personal interests and file download options.
1 INTRODUCTION
The widespread usage of sophisticated mobile
computing technology has lead to the development
of mobile multimedia and communication services
such as Wireless Application Protocol (WAP) and
Bluetooth. Mobile phones and personal digital
assistants (PDA) are now increasingly being used to
run advanced applications such as web browsing,
gaming, playback of music and other applications.
As mobile computing devices (MCD) applications
become more advanced, the programming and
communication features of the MCD also advance.
This has lead to the development of variants of
commonly used languages such as C, Java and
Microsoft Visual Studio.Net as programming
environments for mobile computing devices.
However, not all the functionality of these
programming languages is available for MCDs.
The functionality of application programming
interfaces (API) is usually a public domain
specification. However it is up to the MCD
manufacturer to implement the API. For various
reasons, the API for file transfer using wireless
protocols may not be fully supported. This could be
due to the limited computing functionality the MCD.
For example file transfer functions such as file or
directory browsing are commonly not supported.
This is a problem for application programs that
require file transfer using Bluetooth or the infrared
protocols. The use of Bluetooth or infrared protocols
is attractive for some applications because the
transfer of information is not charged and does not
require the user to have an account with a service
provider as with WAP.
This paper introduces a Bluetooth based
communications protocol used for the
implementation of multimedia guidebooks.
Multimedia guidebooks are used in museums to
allow users to access information about museum
exhibits. The multimedia guidebook protocol (MGP)
presented in this paper, allows various formats of
152
D’Souza M., Postula A., Bergmann N. and Ros M. (2005).
A BLUETOOTH BASED PROTOCOL FOR MULTIMEDIA GUIDEBOOKS ON MOBILE COMPUTING DEVICES - Experiencing Mobile Locality-Aware
Multimedia in the Palm of Your Hand.
In Proceedings of the Second International Conference on e-Business and Telecommunication Networks, pages 154-157
DOI: 10.5220/0001415301540157
Copyright
c
SciTePress
information files to be passed between a client and a
server using a Bluetooth connection. The MGP is
also designed to convey the language type of the
transferred file contents and to be implemented on
any MCD with limited computing and wireless
communication capabilities.
Typical interaction between the user and the
information host involves 2 main processes: the
registration process, where a user is introduced to
the system; and a connect-and-request process,
where the user selects the item they wish to retrieve.
The user experiences the items requested by way of
the text, image and audio/video viewers already
located on the MCD.
This paper is organized into 5 sections. Section 2
presents a review of related work. Section 3
describes the MGP architecture and implementation.
Future areas of investigation are discussed in section
4 and conclusions are drawn in section 5.
2 RELATED WORK
There are two types of multimedia guidebook
protocols. The first type involves the information
being transferred to the MCD on request. The
second type already has the information stored on
the MCD. Examples are the Exploratorium (Hsi
2002), (Haneef and Ganz 2002) and the Cyberguide
guidebooks (Abowd, Atkeson et al. 1997). Existing
guidebooks tend to use older short-range wireless
protocols such infrared communications. This is due
to the widespread usage of infrared transceivers on
older personal digital assistant (PDA) platforms.
Infrared is not widely integrated into MCDs as
Bluetooth has become. Infrared has been surpassed
by Bluetooth in many applications because it does
not require line of sight, supports ad-hoc networking
and has more robust data communications.
Bluetooth does support some legacy protocols that
were developed for Infrared such as object exchange
file transfer profile.
The Exploratorium guidebook deploys Radio
Frequency Identification (RFID) beacons, 802.11b
wireless LAN and HP Jornada PDAs. When a user
with a PDA comes within range of an RFID beacon,
a uniform resource locator (URL) number is sent to
the PDA via infrared. The Hypertext Transfer
Protocol (HTTP) is then used by the PDA to request
and receive the information via the 802.11b LAN
connection.
3 MULTIMEDIA GUIDEBOOK
PROTOCOL ARCHITECTURE
The multimedia guidebook protocol (MGP) is a
Bluetooth based protocol for use with multimedia
guidebooks on mobile computing devices (MCD).
The MGP was designed to be simple enough to
implement on MCDs that have limited computing
and wireless communication resources. The
Bluetooth wireless protocol supports two basic
information transfer profiles: serial port profile
(SPP) and the OBEX file transfer (OBEX-FTP)
profile (Bluetooth SIG). The MGP uses the SPP as a
control channel and the OBEX-FTP to transfer
information item files. The control channel is used to
convey request and response MGP packets. Figure 1
shows the Bluetooth protocol stack (Bluetooth SIG)
integrated with the MGP and the communication
structure between the host device and the MCD.
3.1 Multimedia Guidebook Protocol
State Machine
The MGP is designed to be a request and response
protocol between a host device and a mobile
computing device. The host only responds to
requests from the MCD. The MGP state machine
message passing sequence can be seen in Figure 3.
The MGP state machine consists of 5 states:
registration, connection, menu initialization,
information item request and disconnection. The
MGP state machine on both the host and MCD does
implement a timeout to ensure that idle
communication links are disconnected. During the
registration phase, the MCD’s Bluetooth address is
registered as a user identifier (UID) in a user
database that is accessed by the host. This allows the
host to only accept requests from registered MCDs.
When the MGP state machine enters the
connection phase, the host authenticates the MCD’s
UID and allows the connection if the UID is
Figure 1: MGP – Bluetooth Stack Integration and
Communication Channels
A BLUETOOTH BASED PROTOCOL FOR MULTIMEDIA GUIDEBOOKS ON MOBILE COMPUTING DEVICES
153
registered. Once the host and MCD are connected,
an item initialization menu packet (IIMP) is sent to
the MCD from the host. The IIMP contains a list of
information items that can be accessed from the
host. Once the IIMP has been transferred, the user
will see a menu of information items to select from.
When a user selects an information item to view,
mobile computing device’s MGP state machine
enters the information item request phase. An MGP
item request packet is sent to the host from the
MCD. The host responds with an acknowledge
packet and it also transfers the information item file
to the MCD using the OBEX-FTP channel. When
the user wants to disconnect their MCD from the
host, the MGP state machine enters the
disconnection phase and transmits an MGP
disconnection packet to the host.
3.2 Multimedia Guidebook Protocol
Structure
The MGP packet structures containing ASCII values
can be seen in Figure 2. The packets are designed to
be received and transmitted through a normal
Bluetooth serial port connection. There are two
types of packets: request and response packets. Each
packet consists of a packet header that contains the
command field and the UID field. The request
packet contains the number of requested information
items and the information item numbers (IIN) of the
information items to be requested. The response
packets contain the IIN of the information item sent
as well as the number of items remaining to be sent.
The IIN is described in section 3.3.
The initialize item menu packet (IIMP) payload
contains the total number of accessible information
items, followed by the information item fields of
each information item. Delimiter characters are used
to separate the information fields. The structure of
the IIMP is given in Figure 4.
3.3 Information Item File Formats
The information items are transferred as files
through the Bluetooth OBEX-FTP channel. Each
information item file is assigned an information item
number (IIN). The IIN is only unique to a particular
host. The structure of the IIN can be seen in Figure
4, consists of an item type, language and number
fields. The number field is a random number
assigned by the host. The item type specifies the
format of a file. Common formats such as JPG and
MP3 are used. The language field contains a number
that specifies what language the file content is in. A
preliminary language list is given in Figure 4. The
information name field contains the text that is seen
by the user on their MCD. The menu type field
determines if the information name field is viewed
either as normal or it appears as a submenu item.
Figure 2: MGP Packet Fields
Figure 3: Multimedia Guidebook Protocol State
Machine and Message Passing Sequence
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4 FUTURE WORK
Future work associated with the development of this
protocol, would be to expand its facilitation of user
options. In order to make this technology available
to more people, further work must be done in the
expansion of the current field options – for example,
the inclusion of many more languages or item types.
As well as fledging out the current fields, further
work needs to be done on the development of other
user preferences as new fields. Some suggestions
include fields for file size preferences
(smaller/quicker vs. larger/detailed), experience type
(streaming vs. wait-until-downloaded), personal
interests (historical/architectural point-of-view) as
well as options for visually or hearing impaired
persons (captions/Read-Aloud).
5 CONCLUSION
A protocol for a multimedia guidebook was
presented in this paper. The multimedia guidebook
protocol was designed to be simplistic so that it
could be implemented onto any mobile computing
device with limited computing and programmability
capability. The MGP was also designed to overcome
some of the wireless file transfer limitation issues
with mobile computing devices and was
implemented using a Bluetooth serial port and
OBEX-FTP connections. The MGP allows the
transfer of various file formats such as image or
audio files and also identifies the language content
of the information file. Future work on this protocol
involves expanding the current field options to allow
for other languages to be included and for other user
preferences such as personal interests and file
download options.
ACKNOWLEDGEMENTS
This work is supported by the ACID CRC
Connected Communities Project and is also a part of
the EU Project RUNES.
REFERENCES
Abowd, G. D., C. G. Atkeson, et al. (1997). "Cyberguide:
a mobile context-aware tour guide." Wirel. Netw.
3(5):
421-433.
Haneef, A. M. and A. Ganz (2002). Mobile agent based
network access for mobile electronic guidebooks.
Mobility and Wireless Access Workshop.
Hsi, S. (2002). The Electronic Guidebook: A study of user
experiences using mobile web content in a museum
setting. IEEE International Workshop on Wireless and
Mobile Technologies in Education.
Bluetooth SIG. Bluetooth Specification Documents
https://www.bluetooth.org/spec
Fi
g
ure 4: Structures of the Information Item
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