Wipro-NewLogic is an Associate Member of the Bluetooth SIG


http://www.bluetooth.com/

What is Bluetooth wireless technology?

Bluetooth wireless technology is a wireless standard started and promoted by Ericsson. It is a wireless specification that describes how mobile phones, computers, personal digital assistants (PDAs), and any other wireless product can easily interconnect with each other. Using this technology, users of cellular phones, pagers, and personal digital assistants such as the PalmPilot will be able to buy a three-in-one phone that can double as a portable phone at home or in the office, get quickly synchronized with information in a desktop or notebook computer, initiate the sending or receiving of a fax, initiate a print-out, and, in general, have all mobile and fixed computer devices totally coordinated. The technology requires that a low-cost transceiver chip be included in each device.

What do the different parts do?

Radio - a frequency hopping radio, after every transmission or reception it 'hops' or changes frequency. This is done so that it can avoid intereference. Bluetooth wireless technology uses the ISM (Industrial Scientific and Medical) band around 2.4 GHz because it's available unlicensed in most countries, but because it's unlicensed Bluetooth wireless technology must compete with other technologies, so it’s subject to interference. Baseband - assembles various different packets for transmission, receives packets, checks them and passes them up the stack if they are correct. It also handles retransmission of errored packets and manages simple low level flow control.

What are profiles? What are they for?

The profiles describe ways the Bluetooth Core specification can be used in different products. The idea is that if everybody follows the profiles then products will interoperate. So for instance they describe how to connect with a headset, what records should go into Service Discovery databases, and what names to use for features.

What do you mean by "qualified"?

There is a testing process administered by the Bluetooth SIG which is intended to make sure that any device labelled with the Bluetooth brand will work correctly. This process is called Qualification, and qualified products are listed on the Bluetooth web site.

About Radio Frequency

The radio frequency (RF) system will process the analog or digital signals in high frequency to be transmitted over the air. There will be a link between transmit and receive antenna. Bluetooth use a frequency of 2.4 GHz for transmission.

Some important key words

• LMP - Link Management Protocol - sets up and configures links
• HCI - Host Controller Interface - allows the Bluetooth stack to be split between a module and a host in a standard way.
• L2CAP - Logical Link Control and Adaptation Protocol - segments and reassembles data packets from higher layers, so that Bluetooth wireless technology can handle large packet sizes. Also multiplexes different higher layer protocols onto the lower layer ACL (data) links. All user data sent on a Bluetooth link must be sent through L2CAP.
• SDP - Service Discovery Protocol - Allows devices to exchange information about services they provide. A service is any feature which can be used across a Bluetooth link.
• RFCOMM - Radio Frequency communications port - a serial port emulation layer.
• TCS - Telephony control Specification - allows telephone call signalling to be passed around Bluetooth devices
• OBEX - taken from the Infra Red Data Association (IrDA) this layer allows you to exchange data objects such as files, calendar information or virtual business cards
• WAP - Bluetooth wireless technology can act as a bearer (transport) layer for WAP. WAP allows a simplified version of a web browser to run on mobile devices with small screen sizes.