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What is Bluetooth?

Bluetooth is one of the most efficient short distance wireless communication devices in our daily lives. With its stability and convenience in communication, this has allowed Bluetooth technology to become a valuable asset for both computers and electronic communication. It was first developed by a group called Bluetooth Special Interest Group (SIG) which formed by elite companies such as Ericsson, Nokia, Intel, IBM and Toshiba in May 1998. Bluetooth technology was officially approved in the summer of 1999. Since then the creation of Bluetooth wireless communication is widely used in various electronics and has been expanding everyday. Starting from communication between mobile phones and computers, Bluetooth has expanded to enable communication between such forms as headsets, printers and automobiles.

Bluetooth is a combination of hardware and software technology, running on a hardware radio chip and utilizing software to provide the main control and security protocols. By using this newer hardware and smarter software algorithms to direct network data we can achieve more efficient, flexible and secure wireless communications. The future is geared towards wireless communication as the cables seen on desktops are slowly becoming obsolete. The movement towards Bluetooth is rapidly rising and the low cost and efficiency is a clear indication of the unlimited possibilities of Bluetooth.

How does Bluetooth Work?

Bluetooth establish connection using Radio waves signal, it broadcasts its signal at Radio frequency of 2.45 Gigahertz. The picture to the immediate right is the Bluetooth radio chip that provides the communication between devices. Once the hardware radio chip is installed on two electronic devices, wireless communication can be established hopping channels up to 1600 times per second.

Because Bluetooth is using Radio waves to achieve communication, the main chip operates with frequency hopping and thus does not need a clear path between two devices.

The control of communication aspect is more complicated and software plays an important role to control communication. Every main Bluetooth chip has an identity coding and different types of links. Both of these characteristics of the chip allow two different devices to communicate. Two devices must have the same type of linkage in order to establish communication.

The concept behind a Bluetooth communication is the use of masters and slaves. The master works as the moderator between communication between itself and the slave as well as between the slaves themselves. The Bluetooth network can link up to eight devices with this use of masters and slaves. This type of network is referred to as a piconet. As a connection needs to be made between two slaves, then one slave will “act” as a master and communicate to the other slave while still maintaining connection to the original master.

The software will first send a page from the master to the slaves and the slaves will listen for its device access code. If there is a match, then a connection is established. Once this connection is established, then a NULL packet is sent from the master to the slave and the master must wait for the slave to respond. At this point the Link Manager Protocol (LMP) takes over.

The LMP is comprised of Mandatory Protocol Data Units and these are transferred between devices through a single packet. When a connection is requested, the requesting device must send LMP_host_connection_req. The requested device can respond with either LMP_accepted or LMP_not_accepted. Once the linkage is complete, LMP_setup_complete is sent and packets are transmitted.

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