Communication Using Bluetooth Technology
May 2, 2009
Bluetooth is a type of communication protocol that devices use to wirelessly communicate with each other. Initially, Intel, Toshiba, Nokia, IBM, Compaq, Dell, HP, Motorola, Samsung, Lucent were some of the companies to come together to form an organisation known as Special Interest Group or the SIG. Their main purpose was to set-up a short frequency wireless technology for transferring and receiving data. They thus introduced a technology known as Bluetooth.
Bluetooth can be described as a communication language used by machines. Its operation is based on the Master & Slave format. The devices form a network within a short range. This network is known as Piconet. It has been observed that within a single coverage area about 10 pico-nets can co-exist. The master device has the capability to connect to more than one slave devices simultaneously. However at any single given moment, it can only connect to one slave unit. As the master switches between different slaves pretty fast, it seems to be connected to many slaves at the same time. Two or more pico-nets are linked using Bluetooth, however this can only be done over a short range. Bluetooth communication is possible between PDAs, laptops, mobile phones, digital cameras, scanners, printers and many other electronic widgets.
Now let’s see how a connection is established between similar Bluetooth compatible devices. Initially, all the devices will remain in a “Passive State”. In the passive state, the gadgets are all in contact with the network, yet are not performing any action. The actual connectivity establishment process starts with a process known as the “Inquiry Process”. In this stage, the master unit sends a request to all the devices that are found in its range. The devices which receive this request send a response signal that contains their respective addresses. Amongst all the responses received, the master selects one address and synchronises with it at a point that is termed as an access point. This synchronisation process is known as “Paging Technique”, which involves the alignment of the device’s clock and frequency with that of the access point.
The next process in the Bluetooth Communication Protocol is called as the “Service Discovery Phase”. Here a link is established and the master unit enters the access point using a service discovery protocol. For transferring information, a “Communication Channel” is to be created. In some cases, the access point may include some kind of security mechanism, which requires an encryption key (PIN in common terms) to be unlocked. Once the PIN is sent and received as well as confirmed by both the devices, a communication channel is established. You can now transfer data or information.
The same process takes place while using Bluetooth network for hands free calling purposes. Ideally a communication channel is first established between a bluetooth compatible phone and a satellite navigator (that has bluetooth compatibility). Next as the phone receives a call, it is transferred to the sat nav and you can now answer of reject the call. Similarly you can also make a call trough your sat nav in turn getting connected to your mobile phone.
Bluetooth is often mistaken for a type of broadband networking technique. It is not any kind of long distance or broadband communication technique but is a type of Personal Area Network that can be used in many crucial applications. Bluetooth technology uses the same frequency range as that of the Wi-Fi system. The only criteria is that Bluetooth requires a careful co-ordination of the various frequencies along with the perfect transmit and receive timings. Recently an enriched version of Bluetooth is being designed that is expected to use the Ultra Wide Band frequencies for improved signal strength and increased data transfer rate.
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