BLUETOOTH TECHNOLOGY in WIRELESS COMMUNICATION

ABSTRACT:-

Today, electronics that connect to one another are found everywhere--in the office, home, Car, etc. Keyboards connect to computers, MP3 players to headphones and so on. So, how do these devices connect to each other? Usually the answer is: with wires and cables. But, as you know, wires and cables always result in a tangled mess.

Bluetooth wireless technology eliminates many of the wires that clutter our offices, homes, etc., while allowing our electronic devices of today and tomorrow to with one communicate another .Bluetooth technology has been around for years, however for many people it is just another “tech” term.

Bluetooth technology is how mobile phones, computers, and personal digital assistants (PDAs), not to mention a broad selection of other devices, can be easily interconnected using a short-range wireless connection. Using this technology, users can have all mobile and fixed computer devices be totally coordinated.

This presentation explains the present scenario of using wireless technology for transmission of data .This includes working of Bluetooth wireless technology, protocols used, profiles and specifications needed for transmission,security provision and includes some of the devices using bluetooth.









INTRODUCTION


Today, electronics that connect to one another are found everywhere--in the office, home car, etc. keyboards connect to computers, MP3 players to headphones and so on. So, how do these devices connect to each other? Usually the answer is: with wires and cables. But, as you know, wires and cables always result in a tangled mess
Bluetooth wireless technology eliminates many of the wires that clutter our offices, homes, etc., while allowing our electronic devices of today and tomorrow to with one communicate another .Bluetooth technology has been around for years, however for many people it is just another “tech” term.
Most people have little or no understanding of the technology and have very little knowledge of its applications. However, you hear and read about it everywhere--in ads for computers, cell phones, PDAs and all types of different devices enabled with Bluetooth technology.
What is Bluetooth wireless technology?
Bluetooth technology is how mobile phones, computers, and personal digital assistants (PDAs), not to mention a broad selection of other devices, can be easily interconnected using a short-range wireless connection. Using this technology, users can have all mobile and fixed computer devices be totally coordinated.
Bluetooth wireless technology is a short-range radio technology. Bluetooth wireless technology makes it possible to transmit signals over short distances between telephones, computers and other devices and thereby simplify communication and synchronization between devices. Generally, Bluetooth has a range of up to 30 ft. or greater, depending on the bluetooth core specification version. Newer devices, using newer versions of Bluetooth, have ranges over 100 ft.
It is a global standard that:
· eliminates wires and cables between both stationary and mobile devices;
· facilitates both data and voice communication;
· offers the possibility of ad hoc networks and delivers the ultimate synchronicity between all your personal devices.
Bluetooth technology is actually derived from a combination of wireless technologies. The Bluetooth specification unites these technologies under the title: "Bluetooth technology". Bluetooth radio uses a fast acknowledgement and frequency-hopping scheme to make the link robust, even in noisy radio environments. Due to the fact that Bluetooth technology is a standardized wireless technology, you can rest assure it will be around for many years to come.

HISTORY :
The Bluetooth SIG:
The name “Bluetooth” and its logo are trademarked by the privately held trade association named the Bluetooth Special Interest Group (SIG).
Founded in September 1998, the Bluetooth SIG is a unification of leaders in the telecommunications, computing, network, industrial automation, and Automotive industries. Today, the Bluetooth SIG is responsible for encouraging and supporting research and development in Bluetooth technology.
The Bluetooth SIG includes promoter member companies Microsoft, Ericsson, IBM, Intel, Agere, Motorola, Nokia, and Toshiba, plus thousands of Associate and Adopter member companies .
· Why is It Called Bluetooth?
The developers of this wireless technology first used the name "Bluetooth" as a code name, but as time past, the name stuck.
The word "Bluetooth" is taken from the 10th century Danish King Harald Bluetooth. King Bluetooth had been influential in uniting Scandinavian Europe during an era when the region was torn apart by wars and feuding clans.
The founders of the Bluetooth SIG felt the name was fitting because: 1) Bluetooth technology was first developed in Scandinavia, and 2) Bluetooth technology is able to unite differing industries such as the cell phone, computing, and automotive markets. Bluetooth wireless technology simplifies and combines multiple forms of wireless communication into a single, secure, low-power, low-cost, globally available radio frequency.
· Where Did the Logo Come From?
A Scandinavian firm originally designed the logo at the time the SIG was formally introduced to the public. Keeping to the same origin as the Bluetooth name, the logo unites the Runic alphabetic characters "H", which looks similar to an asterisk, and a "B", which are the initials for Harald Bluetooth. If you look close enough you can see both embodied in the logo.
How Bluetooth Works?
In order to understand how Bluetooth technology works, we must first take a look at how electronic devices (Bluetooth or not) connect and communicate with one another.
There are several questions that need to be addressed before any two devices can communicate with one another.
Q: Will the devices communicate via wires or through the air?
A: Obviously, if the devices are using Bluetooth technology, they will communicate without wires. However, if the devices are not Bluetooth enabled, then they have the option of communicating either with or without wires. Devices can take advantage of several wireless technologies (Bluetooth included) by using various transmitters to send information over the airwaves.

Q: How will messages or information be sent between the two devices?
A: Information can be sent one bit at a time in a scheme called serial communications, or in groups of bits (usually 8 or 16 at a time) in a scheme called parallel communications.
Q: How will devices in this “electronic conversation” know what the information (bits or groups of bits) means? How will they know if they received the same message that was sent?

A: Most of the time these questions are answered by the creation of what is known as a protocol. A protocol is a standard that controls or enables the connection, communication, and data transfer between two electrical devices. Basically, a protocol is the "language" of devices.With so many different types of electronics available, it is probably no surprise that there are tons of established protocols. However, almost all protocols address one or more of the following:
* Detecting the presence of other devices* Establishing communications guidelines between two devices (AKA: Handshaking)* Determining the various connection characteristics* How to format a message* How to start and end a message* What to do with corrupted or incorrectly formatted messages* How to recognize unexpected connection loss, and what to do next* Ending the connection or “conversation”

Bluetooth: Low Power and Low Cost!
Bluetooth wireless technology operates on an open frequency within the 2.4 gigahertz band, which is the same as WiFi, cordless phones and various other wireless devices. Bluetooth is able to share the same frequency band without experiencing any interference because it utilizes various key technologies.
One of the ways Bluetooth avoids interference is through the use of low power signals (around one milliwatt). Devices using the Bluetooth Core Specification Version 1.1 or later are able to avoid interference with other wireless devices because their signal is so weak. Take into consideration that powerful cell phones use a signal of around three watts. Even though the signal is weaker, Bluetooth still offers a range of up to 30 feet (Newe versions can have a range over 100 feet).
The signal is also capable of passing through the walls in your home, making it useful for controlling several devices in different rooms. Data can be transferred at a rate of up to one Megabyte per second (Mbps).
Also, because Bluetooth transmitters require minimal amounts of power, they are relatively inexpensive to manufacture. Simply put, Bluetooth uses low-power radio waves to reliably communicate in an inexpensive way.
“Hopping” = No Interference
Another way Bluetooth devices are able to avoid interference is through a technique known as spread-spectrum frequency hopping. By using the “hopping” method, a device will use one of 79 different, randomly chosen frequencies within an assigned range, and will frequently change frequencies from one to another.
Bluetooth enabled devices, which all use the “hopping” method, change frequencies 1,600 times per second. As a result, more devices can use a portion of the radio spectrum.The risk of a device like a cell phone or baby monitor interfering with Bluetooth devices is minimized, since any interference on a specific frequency will last for only a fraction of a second.Bluetooth version 2.0 + EDR, the very latest of the Bluetooth specification versions, uses an enhanced technology called: Adaptive Frequency Hopping (AFH).
AFH allows Bluetooth devices to measure the quality of the wireless signal and then determine if there are bad channels present on specific frequencies due to interference from other wireless devices.If bad channels are present on a specific frequency, the Bluetooth device will adjust its hopping sequence to avoid them. As a result, the Bluetooth connection is stronger, faster, and more reliable.
Bluetooth Profiles: How Bluetooth is Used
Bluetooth enabled devices must use and understand certain Bluetooth "profiles" in order to use Bluetooth technology to connect to one another. These profiles define the possible applications that a Bluetooth enabled device can support.In order for one Bluetooth device to connect to another, both devices must share at least one of the same Bluetooth profiles.




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Bluetooth Pairing
If you are familiar with Bluetooth wireless technology, you'll probably recognize the term "Bluetooth pairing". But do you actually know what Bluetooth pairing means?
Bluetooth pairing occurs when two Bluetooth devices agree to communicate with each other and establish a connection.In order to pair two Bluetooth wireless devices, a password (passkey) has to be exchanged between the two devices. A Passkey is a code shared by both Bluetooth devices, which proves that both users have agreed to pair with each other.
This is the normal process that occurs with Bluetooth pairing:
Bluetooth device A looks for other Bluetooth devices in the area
In order to find other Bluetooth devices, Bluetooth device A must be set to discoverable mode. When set to discoverable, Bluetooth device A will allow other Bluetooth devices to detect its presence and attempt to establish a connection.
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Bluetooth device A finds Bluetooth device B
Usually the discoverable device will indicate what type of device it is (Such as a printer, cell phone, headset, etc.) and its Bluetooth device name. The Bluetooth device name is the name that you give the Bluetooth device or the factory name that originally was programmed.


Bluetooth Device A prompts you to enter a password (PassKey)
With advanced devices, both users must agree on the Passkey and enter it into their device. The code can be anything you like as long as it is the same for both Bluetooth wireless devices.On other devices, such as Bluetooth headsets, the Passkey stays the same. Refer to the product’s manual for the default passkey. Most often , the passkey is zero.
Bluetooth device A sends the Passkey to Bluetooth device B


Bluetooth device B sends the Passkey back to Bluetooth device A
If both Passkeys are the same, a trusted pair is formed. This will happen automatically.
Bluetooth device A and B are now paired and able to exchange data


Bluetooth technology must be examined in two separate sections in order for you to understand the entire process of how the technology works and how it is used.
* The Bluetooth protocol defines how the wireless technology works, and
* The Bluetooth Profiles describe and organize how the technology is used.
Protocol:
Overview of the Bluetooth Protocol
The Bluetooth standard requires a basic level of communication between devices, so that they can connect to each other over the airwaves, at the correct frequencies, using the correct channels, and finding the correct destination(s). In order to create this basic level of communication, a specific protocol was created. The Bluetooth protocol establishes the set of rules by which all Bluetooth devices must abide in order to establish a connection to communicate with one another.
Protocol stack
Most protocols, Bluetooth’s included, are usually layered together into “protocol stacks”, and the various tasks are split up and assigned to the different layers of protocols in the stack.




Bluetooth Protocol Architecture
Bluetooth Protocol Stack
Here is an outline of the different levels in the Bluetooth protocol stack:
Radio Layer
When looking at the different layers of the Bluetooth protocol stack, you will always find the raio layer first. Everything in Bluetooth runs over the Radio Layer, which defines the requirements for a Bluetooth radio transceiver, which operates in the 2.4GHz band. The radio layer defines the sensitivity levels of the transceiver, establishes the requirements for using Spread-spectrum Frequency Hopping and classifies Bluetooth devices into three different power classes:
* Power Class 1 – long rang devices (100m),
* Power Class 2 – normal or standard range devices (10m), and
* Power Class 3 – short (10cm)-range operation
Baseband Layer
The next “floor” in the Bluetooth protocol stack is the Baseband Layer, which is the physical layer of the Bluetooth. It is used as a link controller, which works with the link manager to carry out routines like creating link connections with other devices. It controls device addressing, channel control (how devices find each other) through paging and inquiry methods, power-saving operations, and also flow control and synchronization among Bluetooth devices.
Link Manager Protocol (LMP)
A Bluetooth device’s Link Manager Protocol (LM) carries out link setup, authentication, link configuration and other protocols. It discovers other LMs within the area and communicates with them via the Link Manager Protocol (LMP).
Host Controller Interface (HCI)
Next in the protocol stack, above the LMP is the Host Controller Interface (HCI), which is there to allow command line access to the Baseband Layer and LMP for control and to receive status information. It’s made up of three parts: 1) The HCI firmware, which is part of the actual Bluetooth hardware, 2) The HCI driver, which is found in the software of the Bluetooth device, and 3) The Host Controller Transport Layer, which connects the firmware to the driver.
Logical Link Control and Adaptation Protocol (L2CAP)
Above the HCI level is the Logical Link Control and Adaptation Protocol (L2CAP), which provides data services to the upper level host protocols. The L2CAP plugs into the Baseband Layer and is located in the data link layer, rather than riding directly over LMP. It provides connection-oriented and connectionless data services to upper layer protocols.
RFCOMM
Above L2CAP, the RFCOMM protocol is what actually makes upper layer protocols think they’re communicating over a RS232 wired serial interface, so there’s no need for applications to know anything about Bluetooth.
Service Discovery Protocol (SDP)
Also relying on L2CAP is the Service Discovery Protocol (SDP). The SDP provides a way for applications to detect which services are available and to determine the characteristics of those services.




Bluetooth Profiles

Overview of Bluetooth Profiles
The Bluetooth SIG states, "Bluetooth profiles are general behaviors through which Bluetooth enabled devices communicate with other devices."
In order to connect to one another, devices that use Bluetooth technology must support and understand certain Bluetooth profiles. Bluetooth profiles define the possible applications and describe how Bluetooth technology is to be used for each specific device.
For example, the File Transfer profile is used to define how devices like a PDA will use Bluetooth Technology to transfer files to other devices like another PDA, cell phone, or computer.When a Bluetooth device is developed, the manufacturer assigns (In accordance with the Bluetooth SIG's requirements) specific Bluetooth profiles for that device to use in order to establish applications which will work with other Bluetooth devices.
In order for one Bluetooth device to connect to another, both devices must share at least one of the same Bluetooth profiles.
For example, if you want to use a Bluetooth headset with your Bluetooth enabled cell phone, both devices must use the Headset (HS) profile (Defines how headsets and cell phones use Bluetooth technology to connect to one another).
According to the Bluetooth SIG: At minimum, every Bluetooth profile includes information on the following issues:
* Dependencies on other profiles. * Recommended user interface formats. * Particular parts of the Bluetooth protocol stack used by the profile. To perform its functions, each profile uses particular options and parameters at each layer of the stack.


An Example of Bluetooth in Action
The Wireless Office
Imagine a modern day office with various hi-tech, yet common electronic devices.
The first thing an office should have are the basic essentials: a computer, keyboard, mouse, printer and phone. Next, lets say there is a Headset that works with the phone.
Now that we have all the basics, lets make this office a little more exciting by adding some fun "toys", like a PDA, digital camera and MP3 player.
By now you should have a pretty good picture of the office and the various devices in it.
Every device is connected, or is capable of being connected to at least one other device. For example, the keyboard and mouse have to connect to the computer and the PDA has the option to connect to the computer.
Just imagine if all these devices used cables to connect to one another. The office would have cables running everywhere and we'd be left with a big, tangled mess.
Now imagine all of these devices use Bluetooth technology to connect to one another instead. The result: no more cables and no more mess.
Suppose the Bluetooth enabled printer comes with a Bluetooth Computer Adapter that plugs into the computer's universal serial bus (USB) port. The company that manufactured the printer and computer adapter programmed each device with the same Bluetooth profiles.
Bluetooth profiles are used by devices to instruct them on how to use the Bluetooth technology
After the printer is turned on, it transmits a signal, which looks for a response from other Bluetooth enabled devices with the same profile(s). Since the USB adapter shares the same profile(s), it responds and a small network (AKA: Piconet) is created.
Since this piconet is established between devices with the same specific profiles, the signals sent by other devices with different profiles, like the headset, will be ignored. All the other Bluetooth devices in the room establish similar piconets that are all separated from one another based on the specific profile(s) they use.


Bluetooth Security
Bluetooth Technology Faces Security Threats
Today, all communication technologies are facing the issue of privacy and identity theft. Bluetooth technology is no exception. The information and data we share through these communication technologies is both private and in many cases, critically important to us.
Everyone knows that email services, company networks, and home networks all require security measures. What Bluetooth users need to realize, is: Bluetooth requires similar security measures.

The Bluetooth SIG Focuses on Security
The Bluetooth SIG is constantly improving formats for combating security threats associated with Bluetooth technology. Offering a secure method to wirelessly communicate has always been one of the key benefits of Bluetooth technology
In order to lead the security effort, a group of engineers within the Bluetooth SIG formed the Bluetooth Security Experts Group. As the Bluetooth Core Specification Versions continue to advance, the Bluetooth Security Experts Group is responsible for monitoring the advancement and testing for flaws in its security.
The Fundamentals of Bluetooth Security
One of the most basic levels of security for Bluetooth devices is the “pairing” process.
Pairing = Two or more Bluetooth devices recognize each other by the Bluetooth Profiles they share, and in most cases, both must enter the same PIN.
The Bluetooth core specifications use an encryption algorithm, which is entirely secure. Once Bluetooth devices pair with one another, they too are entirely secure.
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How Developers Can Provide Security Companies who develop Bluetooth enabled products have multiple options in order to provide security. There are three security modes for connecting two Bluetooth devices: 1.Security Mode 1: non-secure 2. Security Mode 2: service level enforced security 3. Security Mode 3: link level enforced security It is the company who develops each specific Bluetooth product that decides which security modes to use. Also, the devices and services have different security levels as well.


What is Bluejacking?
Bluejacking allows phone users to send business cards anonymously to one another using Bluetooth technology. Bluejacking does NOT involve any altercations to your phone's data. These business cards usually consist of some clever message or joke. Bluejackers are simply looking for a reaction from the recipient. To ignore bluejackers, simply reject the business card, or if you want to avoid them entirely, set your phone to non-discoverable mode
What is Bluesnarfing?
Bluesnarfing refers to a hacker who has gained access to data, which is stored on a Bluetooth enabled phone. Bluesnarfing allows the hacker to make phone calls, send and receive text messages, read and write phonebook contacts, eavesdrop on phone conversations, and connect to the Internet. The good news is, bluesnarfing requires advanced equipment and expertise or requires the hacker to be within a 30 ft. range. If your phone is in non-discoverable mode, it becomes significantly more difficult for hackers to bluesnarf your phone. According to the Bluetooth SIG, only some older Bluetooth enabled phones are vunerable to bluesnarfing.
What is Bluebugging?
Bluebugging refers to a skilled hacker who has accessed a cell phone's commands using Bluetooth technology without the owner's permission or knowledge. Bluebugging allows the hacker to make phone calls, send messages, read and write contacts and calendar events, eavesdrop on phone conversations, and connect to the Internet. Just like all Bluetooth attacks, the hacker must be within a 30 ft. range. Bluebugging and bluesnarfing are separate security issues, and phones that are vulnerable to one are not necessarily vulnerable to the other.




Bluetooth Specifications
Here Are a Few Specifications From the Bluetooth SIG (Special Interest Group):
Bluetooth devices in a piconet share a common communication data channel. The channel has a total capacity of 1 megabit per second (Mbps). Headers and handshaking information consume about 20 percent of this capacity.
In the United States and Europe, the frequency range is 2,400 to 2,483.5 MHz, with 79 1-MHz radio frequency (RF) channels. In practice, the range is 2,402 MHz to 2,480 MHz. In Japan, the frequency range is 2,472 to 2,497 MHz with 23 1-MHz RF channels.
A data channel hops randomly 1,600 times per second between the 79 (or 23) RF channels.
Each channel is divided into time slots 625 microseconds long.
A piconet has a master and up to seven slaves. The master transmits in even time slots, slaves in odd time slots.
Packets can be up to five time slots wide.
Data in a packet can be up to 2,745 bits in length.
There are currently two types of data transfer between devices: SCO (synchronous connection oriented) and ACL (asynchronous connectionless).
In a piconet, there can be up to three SCO links of 64,000 bits per second each. To avoid timing and collision problems, the SCO links use reserved slots set up by the master.
Masters can support up to three SCO links with one, two or three slaves.
Slots not reserved for SCO links can be used for ACL links.
One master and slave can have a single ACL link.
ACL is either point-to-point (master to one slave) or broadcast to all the slaves. ACL slaves can only transmit when requested by the master.



The Advantages of Bluetooth
Main Reasons to Use a Bluetooth Device:
1. Bluetooth Devices are Wireless.
2. Bluetooth Technology is Inexpensive.
3. Bluetooth is Automatic.
4. Standardized Protocol = Interoperability
5. Low Interference
6. Low Energy Consumption
7. Share Voice and Data
8. Instant Personal Area Network (PAN)
9. Upgradeable



Some of the devices using Bluetooth technology are

1.wireless audio devices
2.bluetooth car where the drivers can restricted to use their cell phones while driving.
3.cell phones using Bluetooth technology
4.bluetooth computer adapters and receivers
5.bluetooth gps receivers
6.bluetooth head sets

Conclusion:
In the future Bluetooth is likely to be standard in tens of millions of mobile phones, PCs laptops and a whole range of other electronic devices. As a result, the market is going to demand new innovative applications. Value-added services, end – to – end solutions, and much more. The possibilities opened up really are limitless and because the radio frequency used is globally available, Bluetooth can offer fast and secure access to wireless connectivity all over the world. With potential like that it is no wonder that Bluetooth is set to become the fastest adopted technology in history.
Reference:
www.bluetomorrow.com