Wireless Future - Telenor

Joakim Persson (35) received
his MSc in Computer Engineering
and his PhD in Information
Theory from Lund University,
Sweden in 1990 and 1996,
respectively. He joined the
research department at Ericsson
Mobile Communications AB in
1996, and from 1999 he is technical
manager for the New Technology
section within this department.
He has been working with
Bluetooth since 1997, and is one
of the key contributors to the
baseband specification. He is
now playing an active role in the
work within Bluetooth SIG that
looks into the future evolution of
the system.
Joakim.Persson@ecs.ericsson.se
Jaap C. Haartsen (38) joined
Ericsson Mobile Communications
in 1991 and has since
worked at sites in RTP, USA and
in Lund, Sweden in the area of
wireless technology. In Sweden
he laid the foundations for the
Bluetooth radio concept. He is
currently located in Emmen, the
Netherlands, where he holds the
position of Expert, Wireless Systems.
He has recently been
appointed adjunct professor at
the Twente University of Technology,
in the area of Mobile Radio
Communications. He earned his
MSc and PhD degrees in electrical
engineering from the Delft
University of Technology, the
Netherlands. He has authored
numerous papers and holds
over 30 patents.
Jaap.Haartsen@eln.ericsson.se
Telektronikk 1.2001
Enabling Wireless Connections
using Bluetooth
JOAKIM PERSSON AND JAAP HAARTSEN
A new wireless technology called Bluetooth has recently emerged as the de facto standard
for wireless ad-hoc connectivity of devices within a relatively short distance from each other.
The technology is supported by a large number of leading companies in the telecom, computer,
and consumer areas. This paper discusses the basic functionality of this system, both
from a technical standpoint as well as from a user perspective. Furthermore, we will also
look ahead and see how some usage scenarios and their particular demands are likely to
influence the technology, leading to the evolution of the system.
1 Background
In 1994, a few people at Ericsson Mobile Communication
sat down to discuss a particular
problem regarding how to connect a laptop to
a mobile phone. The outcome of the discussion
was to opt for a wireless radio link. This simple
application was the origin of what is now known
as Bluetooth. Since then, the system has evolved
considerably. The simple point-to-point connection
that originally was the intended use for
Bluetooth now also includes network functionality.
Many interesting user applications have
emerged which were not envisioned from the
beginning, for instance background synchronisation
(see Figure 1). The special needs of Bluetooth
hosts running on batteries has been
addressed with certain low power modes in
the baseband and link manager protocols.
Certainly, one of the most important aspects of
any communication system is the user experience
and usability. History is full of examples
where systems provide great technologies but
have failed commercially due to insufficient
usability. In the design of Bluetooth, a large
effort has been put into such matters. For
instance, to ensure interoperability between
Bluetooth enabled devices from different manufacturers,
a quite extensive set of rules cutting
through the entire communication protocol
stack, have been created for different usage scenarios.
These rules are referred to as profiles.
Furthermore, a certification procedure is being
developed to ensure that Bluetooth equipment
really complies to the specification, both for the
radio interface and for the different profiles.
2 Technology
In this chapter we will give an overview of the
technical aspects of the Bluetooth technology.
We start with the physical layer and walk
through the different layers defined above this.
The Bluetooth protocol stack is visualized in
Figure 2. The layers L2CAP and below form
Bluetooth-specific protocols. L2CAP is a sort of
adaptation layer between the Bluetooth radio and
standard higher layers (like TCP/IP). However,
for specific Bluetooth functions, additional
higher layers have been defined like the Service
Discovery Protocol, the IrDA interoperability
(object exchange protocol over Bluetooth),
RFCOMM (serial port emulation over L2CAP),
Telephony control protocol, and interoperability
requirements for Bluetooth as a WAP bearer.
Figure 2 does not reveal all these protocols.
Clearly, we can only cover the most essential
parts of the Bluetooth system in the given space.
The complete specification [1] is obtainable
from the URL http://www.bluetooth.com.
Figure 1 Synchronisation of laptop and PDA using Bluetooth and the cellular network
65