The Bluetooth system is a
communication system which
enables both voice communication and data
communication
to
be done on the same system. In 1998, it was made an
open
standard, with five American/Japanese/European
firms
as "promoters." Pieces of equipment which have
received
authentication are assured of having mutual
connectivity.
This abstract gives a summary description of the
communications. The concept of the Bluetooth system
is
to
provide a wireless connection between equipment and
it
can
potentially be applied to all kinds of electronic
equipment.Some of the electronic equipments using
Bluetooth system are: a chip set consisting of an RF
transceiver LSI (ML 7050LA) and a base band
controller
LSI
(ML7051LA),Bluetooth
communication software.
The Bluetooth system is a wireless communication
system
which uses the 2.4 GHz band (ISM band) radio
frequency
which has been allocated for industrial/science and
engineering/medical use without the need for a
license.A variety of electronic equipment, such
as portable telephones, personal computers, etc.,
can
be
connected in a "cable-less" manner.The Bluetooth
network is
configured with two kinds of wireless stations:
master
and
slave stations.A service area called a Piconet is
created,
centered around the master and having a radius of
approximately 10 meters. The master can be placed
in a
state where it can have a maximum of seven slaves
as
active
slaves regularly communicating on the Piconet.The
ML7051LA
base band controller LSI is developed
according to the SPA (Silicon Platform
Architecture)
concept. The Bluetooth communication
processing circuit
is
connected to the APB (AMBA Peripheral Bus) as a
peripheral
block of this platform, in the same way as the UART
(Universal Asynchronous Receiver Transmitter) block
and
the
USB (Universal Serial Bus) block.
The Bluetooth communication processing circuitry,
is
composed of ten kinds of small blocks. These
blocks,
through
control by means of software, perform the functions
of
wireless control, communication processing for each
link,
voice processing, and timing control, which are
specified
by the Bluetooth specifications.Bluetooth
communication
is
structured with software controlling the
communication
processing circuits described above. This processing
software consists of the LC (Link Controller) and
LMP
(Link
Manager.Master: when configuring a Piconet, first,
an "inquiry" operation is performed. While
periodically
sending the "inquiry" signal,information gathering
is
done
to collect the addresses, etc. of the slaves which
exist on
the periphery.Slave: to be accepted by the master,
an "inquiry scan" operation is performed. While
periodically switching the receiving frequency, it
waits for the "inquiry" signal from the master.
Upon
receiving an "inquiry" signal, the address
information,
etc. of the slave is transmitted to the
master.Master:
to
transition the slave to the "connection" state,
the "page"
operation is performed. Within the "page"
operation,
the
slave is notified of active member addresses, the
master
address, and clock phase information.While
periodically
switching the receiving frequency, the slave waits
for
the "page" signal from the master. Upon receiving
a "page"
signal, the master's address and clock-offset
information
are received.After this the master and slave can
mutually
exchange linked information and "connection" has
been
established. The slave obtains the information for
frequency hopping and synchronizing the scrambler
by
calculating it based on the address and clock phase
information which the slave receives from themaster.