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What is Bluetooth?
Bluetooth is a technology that helps in transmitting data between Bluetooth enabled devices over a short distance. It helps the users to communicate with different types of electronic devices connected within the network.
It works on open wireless technology and is designed to transmit data from different fixed and mobile electronic devices as well, apart from the desktop and laptop computers.
- Bluetooth is a wireless technology that comes in different versions and in different data transfer rates.
- The use of Bluetooth today is much more extensive and varied in the world of computers and beyond.
- The Frequency Hopping Spread Spectrum technique helps in avoiding interferences and increasing data transfer speeds incredibly.
- There are two types of Bluetooth architecture namely Piconet and Scatternet.
- This technology is secure and consumes less power but the difference in drivers and versions may result in compatibility issues.
Bluetooth is a wireless technology named after a Danish Viking King Harald. He was also called King Harald Blatand, where Blatand means “Bluetooth” in English.
The Bluetooth technology was started in 1994 by Ericsson Mobile Communications. Check out pros and cons of using Bluetooth.
This was then used as an alternative to those cumbersome cables needed to connect mobile phones with computers and other devices.
Later on, in 1998, the Bluetooth Special Interest Group or SIG was formed by different companies such as:
- IBM and
The SIG took on the responsibility of publishing different versions of Bluetooth with different standards, features, and speed of data transfer.
- The first version of it was released in 1999. This version of Bluetooth was of 1.2 standard. The data transfer rate of it was 1 Mbps.
- The second version was of a different standard, 2.0 + EDR, and had a data transfer speed of 3 Mbps.
- The standard of the third version was 3.0 + HS and had a speed of data transfer as high as 24 Mbps.
- The latest version is 4.0.
Bluetooth with infrared is the most significant and latest wireless technology developed with an intent to accomplish WPAN or Wireless Personal Area Network. This is a wireless LAN technology that is mostly used to connect different devices to communicate such as:
- Laptop and desktop computers
- Printers and other accessories of a computer network system.
Nowadays, the use of Bluetooth technology is even more extensive and varied. It is included in both computers and non-computer applications such as:
- Wireless mouse and keyboard of a computer
- Modern healthcare computers to send images and signals to the monitors
- Palmtops and
- Mobile computers to connect to the fixed Local Area Network.
The Bluetooth device comes with a radio transmitter built in it that operates in a short range.
The technology uses the radio waves transmitted. These waves are omnidirectional and are effective enough to pass through any non-metal barriers and even walls.
These waves help in transferring data at the rate of 1Mbps using a 2.4 GHz bandwidth. The data is transferred automatically when the devices are within its range. The user hardly can notice such transfers.
As for the ISM band used by Bluetooth, it is divided into 79 channels. Each of these channels are of 1 MHz frequency.
Bluetooth, as said earlier, uses the FHSS or Frequency Hopping Spread Spectrum method in its physical layer. This helps it to avoid interference that are caused by the other computing devices connected to the network.
This raises its functionality and speed to an incredible 1600 times per second. It means that each of the devices connected in the network will be able to change its modulation frequency 1600 times per second.
The Bluetooth frame format has different fields such as:
- The Access Code – This 72-bit field contains the synchronization bits and also identifies the master.
- The Data – This field contains the control information and data that are sent by the upper layers and can be 0 to 2744 bits in length.
- The Header – This is a 54-bit field that contains the 18-bit pattern which is repeated for three times.
The Header field, however, may be divided into six different subfields such as:
- The Address, which is a 3-bit field and can define slaves 1 to 7. If this address is 0, then it is used for broadcasting communication between the primary and secondary nodes.
- The Type, which is a 4-bit field that classifies the type of data received from the upper layers.
- The F, which is a flow bit and is used to control the flow of the frames. When this F is set to 1, the computer will not be able to receive any more frames.
- The A, which indicates its use or acknowledgement.
- The S, which contains the sequence number of the frames. This helps in easy identification of the data that needs to be retransmitted. This uses a stop and wait protocol, and, therefore, only one bit is enough.
- The Checksum, which is an 8-bit field that helps in detecting errors, if any, in the Header.
This is the entire structure of Bluetooth that helps it in working on different networks establishing a connection between one or many computers.
Background and Nomenclature
The range of operation of the Bluetooth enabled computers depend on the network it is using as well as the class of the device. These devices include:
- Personal computers
- MP3 players
- Mobile phones and
- Different other peripherals.
Just as the functionality and potential of Bluetooth is fascinating and interesting, so is its naming.
The name ‘Bluetooth’ does not sound very technical and it is not an abbreviation that stands for something meaningful and techie.
It is all related to the man behind it.
The name ‘Bluetooth’ is related to a man and dates back a thousand of years to the era of King Harald Gormsson, nicknamed ‘Bluetooth.’ The Viking King Harald of Scandinavia was known for two specific things:
- One, uniting Norway and Denmark in 958 and
- Two, his dark blue or grey colored dead tooth.
Since the Bluetooth network unites two separate electronic devices, it is therefore called by this name. The original logo of Bluetooth is a bind rune.
It is designed by merging the Younger Futhark runes Bjarkan or ᛒ symbol and Hagall or the ᚼ symbol. These were the initials of King Harald Gormsson.
It was actually Jim Kardach of Intel who suggested this name, Bluetooth, albeit as a temporary code name.
Kardach supported his decision saying that just as King Harald ‘Bluetooth’ helped in uniting Scandinavia, this device is also intended to unite the cellular and personal computer using a short-range wireless link.
Hence the name ‘Bluetooth’ seems to be just right.
Later on, different other names were also considered to make the device sound as serious and technical as it looks.
Two specific names that were in contention were RadioWire and PAN or Personal Area Networking. Both these names could not make the cut because:
- PAN, though was the front runner, already had tens of thousands of hits all over the internet, as found during research, and
- Unfortunately, and luckily for Bluetooth, a complete trademark search on RadioWire could not be made within the time of launch.
Therefore, the name ‘Bluetooth’ stayed and made a very good and strong impact pretty fast.
It rapidly caught the imagination of the people before the industry majors could give a second thought to change the name.
It became tantamount with short-range wireless technology and spread through the computer industry like wildfire.
Features and Uses
Ideally, Bluetooth was initially designed and marketed as a placeholder, but, over time, it has developed into some of the coolest devices and features.
Bluetooth technology is significantly different from other wireless technologies.
This is with respect to the network and devices it is equipped with.
Ideally, a Bluetooth will use top-performing networks to provide a wide range of services such as:
- Voice transmission
- File pushing and
- Emulation of serial lines.
The features that are normally found in a Bluetooth device include:
- A few specs that are built on the unique Frequency Hopping Spread Spectrum Technology
- FreeBSD stack that operates using radio transmission signals of shorter wavelength which is implemented through the Net Graph framework.
- Block cipher algorithm along with Secure and Fast Encryption Routine or SAFER technology that facilitates confidentiality, security, authentication and key derivation of the computer system.
The network helps the computers to communicate with the master Bluetooth device.
This can establish a wide network with as many as seven devices, depending on the type of Bluetooth used.
After its introduction in 1994, the computer and electronics majors like Intel, Nokia, and Ericsson met together to design a code for collaboration in 1996.
This was done with intent to standardize this short-range radio technology.
There are different uses of Bluetooth such as:
- Wireless communication and control of different mobile, computer and handsfree headsets
- Wireless networking between several computers in regions with restricted service and range
- Wireless communication with computers, peripherals, and I/O devices
- OBEX or With Object Exchange that helps in transfer of files, contact details, and calendar schedules between various computing devices
- To replace the traditional RS 232 and other wired communication such as medical equipment, GPS receivers, bar code scanners and traffic control devices
- For different low-bandwidth applications where a higher USB bandwidth is not required
- To bridge several industrial Ethernet networks in a computer grid
- A wireless controller in play stations and different interactive games
- Access dialup Internet connection through a personal computer or PDA
- Manage data transmission at a short range between cellular, medical and other types of tele-health devices
- Facilitate Digital Enhanced Cordless Telecommunication or DECT to enrich mobile phone communication
- Track and identify positions of different objects using the real-time location system
- Personal applications for mobile and computer security and
- Track prisoners and livestock movement!
Ideally, Bluetooth facilitates and enhances united communication protocols by giving it a single universal standard.
Types of Bluetooth Network
The Bluetooth technology and architecture creates a small network between the computing devices that the user can access easily without requiring any cables to connect between these devices.
The Bluetooth architecture typically outlines two different kinds of networks, namely:
- Piconet and
Each of these networks different in their features, contents and functionality.
The piconet Bluetooth network contains one master or primary node. There are also seven other different active secondary nodes that are called the slave nodes.
This means that this network has as many as eight active nodes stations. This can operate within a 10-meter distance.
Apart from that, Piconet network will also have as many as 255 parked nodes. These nodes are slave or secondary stations.
These cannot take active part in communicating until and unless these are changed to active state from their parked state.
This is because all communications are between master and slave nodes. There is nothing called a slave-slave communication.
Moreover, the communication between the primary and secondary nodes can be either one-to-one or one-to-many.
The Scatternet network, on the other hand, is formed by merging different piconets. One such piconet is the slave node that acts as the primary or master in other piconet.
This is called the station or node. It can receive the signals sent by the master in the first piconet. It then delivers the same to the other slaves in other piconet.
This is the piconet to which it is acting as the master. This particular node is called the bridge slave.
To understand these networks even better, you will have to take a look at the different layers of the Bluetooth protocol.
Both these networks follow the Bluetooth protocol stack and the different layers of it. This helps in maintaining the universal Bluetooth standard, irrespective of the different layers of its protocol.
The Bluetooth layer structure looks into different aspects such as, it does not allow Bluetooth to follow TCP/IP, OS1 or any other recognized model.
There are different protocol architectures and layers in Bluetooth. One such layer is the radio layer. This layer has the following features and capabilities:
- It handles modulation and radio transmission
- It matches with the carnal layer of OSI model
- It facilitates and expedites the movement of data from the master to slave and the other way round
- It is actually a system of low power and can operate within a range of 10 meters using the ISM band of 2.4 GHz.
It also helps in changing the bits into signals and for that it utilizes a special version of FSK. This is called the GFSK. This is actually an FSK that has the ability to filter Gaussian bandwidth.
Next is the baseband layer, which resembles the MAC sublayer that you will find in a Local Area Network.
This layer structure allows Bluetooth to use Time Division Duplex TDMA, a special form of TDMA, a short for Time Division Multiple Access standard.
Using these specific time slots, the master and slave stations in this network communicate with each other. Normally, the master in each piconet outlines this time slot of 625 µsec.
Actually, in TDD-TDMA model, the communication between the nodes are in half duplex form. This means that they can send as well as receive data both but cannot do that at the same time.
If there are no slaves in a piconet, the network will perform in a different way such as:
- The master will use the even-numbered slots such as 0, 2, 4, and so on, and
- The slave will use the odd-numbered slots.
However, once again, both master and the slave nodes will be able to communicate in the half duplex mode. This works in a specific way, such as:
- The master sends the data and the secondary nodes receive them in slot 0 and
- In slot 1 it is just the opposite where the secondary node sends and the primary node receives the data.
There are a few types of Bluetooth where the piconet network may have more than one slave. In such cases the primary or master will use the even-numbered slots.
The slave node will send this data to the following odd-numbered slot, provided the data packet of the preceding slot is addressed to it.
Ideally, in the baseband layer, the master and slave can create two specific types of links. These are:
- ACL or Asynchronous Connectionless – This link is used by the packet switched data. These are offered at irregular intervals. It performs on the best effort principle to deliver traffic. This means that there is a chance of the frames being lost in transmission and may need to be retransmitted. This is because the slave can access only one ACL link at a time to respond to the master. However, ACL can transfer data at a maximum speed of 721 Kbps. It uses one, three or more slots. This means that the ACL link is best to use if you prefer correct delivery over fast delivery.
- SCO or Synchronous Connection Oriented – This is used to transfer real time data like the sound signals. This is best to use if you prefer faster delivery over accurate delivery. The SCO helps in creating a physical link between the master and the slave. A slave can send data at the speed of 64 Kbps to the master using three SCO links. This helps in preserving definite slots at regular intervals. However, SCO links will not allow resending damaged data packets.
There is also a third layer in Bluetooth technology protocol.
The L2CAP or Logical Link Control Adaptation Protocol Layer, which is also known as the Logical Unit Link Control Adaptation Protocol, is very much similar to the logical link control sublayer of the Local Area Network.
This link helps the ACL link to exchange data but does not allow the SCO link to use it.
The L2CAP performs different functions such as reassembly and segmentation. In this process the L2CAP receives the data packets of maximum 64 KB in size from the upper layers.
It then divides them into several frames before transmitting them. It may also include some additional information in it such as the location of the frame in the data packet.
At the destination, the L2CAP reassembles the frames once again into data packets.
L2CAP also helps in multiplexing and demultiplexing at the sender site and at the receiver site respectively.
- While multiplexing at the sender site, the L2CAP receives data from a single upper layer protocol. It frames and sends them to the baseband layer.
- During demultiplexing at the receiver site, the L2CAP receives the data from the baseband layer to extract and deliver it to the desired protocol layer.
Providing Quality of Service or QOS according to the requirements is another function performed by the L2CAP. This happens both during normal operation of the links or when these links are established.
Finally, it also permits the computers in the network as well as the Bluetooth device to negotiate the optimal size of the payload while establishing a connection.
How Does It Work?
Basically, the Bluetooth works by establishing a personal network between the computers. This is done by the Personal Area Network or piconet.
This contains 2 to 8 Bluetooth peer devices. The working process consists of three major steps.
- Step 1: The only master node here initiates the communication with the devices in the network and at the same time controls the traffic and link between it and the 7 slave nodes or stations related to it.
- Step 2: The slave responds to the master to synchronize the receiving or transmitting timing with it. Once again, it is overseen by the master device.
- Step 3: In order to establish a fast and easy connection, Bluetooth pairing is done. This is a specific scheme that helps two computing devices to communicate with each other. This process of pairing is initiated by the user manually. When the Bluetooth link is visible, it can be then paired.
This pairing process is triggered automatically when it receives the request for establishing a connection for the first time.
A password needs to be exchanged between the devices. This ‘Passkey’ is used as a code by both the Bluetooth devices and ensures that they have agreed to be paired.
Once it is completed, exchange of data can begin between the connected or paired devices within the network.
You will not need to follow the same process all over again for pairing and authentication of the devices every time you connect your computer using Bluetooth.
The Bluetooth specifications help this working process a lot. These specifications include:
- The core specifications that defines the necessities for testing and Bluetooth protocol stack and
- The profile speciﬁcation that deﬁnes the usage models which contains the exhaustive information on how you should use the Bluetooth protocol for different types of requests.
Bluetooth technology uses radio waves that come in 79 different channels or frequencies to send and receive data from one computer to another.
This wave is 2.45 GHz in range and is different from that used by the radio, TV and cell phones. This band is reserved for use by industrial, medical and scientific gadgets.
The short-range transmitters in Bluetooth helps it to create an ad-hoc computer network of smaller range and within a short distance. This is called piconet and will not interfere with another network.
Any device can join or exit from this network. Moreover, two or more distinct piconets can join and share info using the Scatternet network.
Ideally, Bluetooth technology is more secure than Wi-Fi and other networks that work in longer ranges.
Questions & Answers:
What kind of network does Bluetooth use?
The networks used by Bluetooth are basic piconet with 79 channels that provides more flexibility, adapted piconet with 20 and 79 channels to reduce the hop-set, inquiry channel to detect the slave by the master within the range, and paging network to make the physical connection.
Does Bluetooth need Wi-Fi?
No, because these are two different things. Both will need a completely different set of hardware and software to establish a connection.
They also have different sets of protocol, power efficiency and permissible frequency. Therefore, both cannot work together.
Why is it called Bluetooth?
It is named after the Viking King Harald who ruled in medieval Scandinavia and united Norway and Denmark in 958 and converted Danes to Christianity.
He had a dark blue colored dead tooth. Since he united two nations, this technology is named after him as it unites two computing devices.
Bluetooth technology is widely used nowadays as a wireless technology.
From computers to smartphones, this technology helps to connect two devices easily, quickly and without needing any elaborate setup, long cables or hardware.
Bluetooth technology is truly a boon to the world of computers!