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U. Glaeser

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sort of local area network. Support for handling paging is optional in the Bluetooth specification. Another<br />

role of the link managers is to exchange information about each other to make passing data back and<br />

forth more efficient.<br />

The Bluetooth Transceiver<br />

The Bluetooth systems operate in the industrial and scientific (ISM) 2.4 GHz band. This band is available<br />

license free on a global basis and is set a side for wireless data communications. In the United States the<br />

Federal Communication Commission (FCC) sets up rules for transmitters operating in the ISM band<br />

under section 15.247 of the Code of Federal Regulations. The frequency allocated is from 2,400 MHz to<br />

2,483.5 MHz. The Bluetooth transceiver operates over 79 channels each of which is one megahertz wide.<br />

At least 75 of the 79 frequencies hoped to must be pseduo-random. Bluetooth uses all 79 channels and<br />

hops at a rate of 1600 hopes per second.<br />

The Middleware Protocol Group<br />

The Middleware Protocol Group includes ISO layers three and six, which are made up of the RFCOMM<br />

protocol, the service discovery protocol (SDP), IrDA interoperability protocols, IrDA, and Bluetooth<br />

wireless protocol, and the audio and telephony control protocol. Fitting Bluetooth into the ISO model<br />

is really up to the developer. If you want to make it fit it makes sense, but there is lots of strange baggage<br />

imbedded protocols in Bluetooth that makes this difficult to see. First, we have already seen the voice<br />

communication connect down at the L2CAP layer. Now we are faced with how the toss in multiplexed<br />

serial port emulation, IrDA interoperability, and a bunch of protocols from telephony world. No wonder<br />

the standard goes on for thousands of pages and hundreds of companies around the world are struggling<br />

with comparability testing of various Bluetooth devices designed from this very complex specification.<br />

The Application Protocol Group<br />

The Application Protocol Group includes ISO layer seven. This grouping contains the most extensive<br />

variety of special-purpose profiles all of which rely on the six lower levels for service. These include the<br />

generic profiles, the serial and object exchange profile, the telephony profiles, and the networking profiles.<br />

The generic profiles includes the generic access profile and the service discovery application profile.<br />

The serial and object exchange profile contains the serial port profile, the generic object exchange profile,<br />

the object push profile, the file transfer profile, the synchronization profile, the networking profiles, the<br />

dial-up networking profile, the LAN access profile, the fax profile, the telephony profiles, the cordless<br />

telephony profile, the intercom profile, the headset profile, and the cordless telephony profile. Most of<br />

these applications profiles are self-explanatory and are only of detailed interest to the software developer<br />

when developing a specific application using the appropriate profile. This is not to say that they are not<br />

important, but they provide very detailed application programmer interfaces (API) [15].<br />

The possible Bluetooth applications keep expanding. This stimulates interest in expanding the array<br />

of application profiles in the Bluetooth specification. Several of the newer application profiles are the car<br />

profile, a richer audio/video profile, and a local positioning profile.<br />

Bluetooth Development Kits<br />

Given the obvious complexity of the Bluetooth hardware and software applications, having access to<br />

good development kits is essential to speed the implementation of the specification. The first inexpensive<br />

development kit to become widely available to universities was Ericsson’s Bluetooth Application and<br />

Training Toolkit. This is a first generation Bluetooth kit that demonstrates important Bluetooth features<br />

and has a well defined, but extensive proprietary API in C++<br />

. Application development is possible, but<br />

is time-consuming and tedious requiring knowledge of C++<br />

to learn a vast API. Newer kits, specifically<br />

for development, are more efficient.<br />

© 2002 by CRC Press LLC

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