| Blue tooth is initially conceived by Ericsson. The | | | | communications are established between multiple |
| five founding members of the Bluetooth SIG are | | | | stations in a given coverage area without the use |
| Ericsson, IBM, Intel, Nokia and Toshiba. On | | | | of an access point or server. |
| December 1, 1999, the founding members | | | | The client/server network uses an access point |
| announced that 3COM, Lucent, Microsoft, and | | | | that controls the allocation of transmit time for all |
| Motorola have joined the founders to form the | | | | stations and allows mobile stations to roam from |
| Promoter Group with the founding companies. To | | | | cell to cell. The access point is used to handle |
| date, more than 1,200 companies have signed on. | | | | traffic from the mobile radio to the wired or |
| Bluetooth is a standard for a small, cheap radio | | | | wireless backbone of the client/server network. |
| chip to be plugged into computers, printers, mobile | | | | This arrangement allows for point coordination of |
| phones, etc. | | | | all the stations in the basic service area and |
| Blue thooth is a cable-replacement technology. It | | | | ensures proper handling of the data traffic. The |
| uses radio frequencies in the 2.45 GHz range to | | | | access point routes data between the stations |
| transmit information over short distances of | | | | and other wireless stations or to and from the |
| generally 33 feet (10 meters) or less. By | | | | network server. |
| embedding a Bluetooth chip and receiver into | | | | How does Blue Tooth works? |
| products, cables that would normally carry the | | | | Bluetooth uses frequency hopping in timeslots. |
| signal can be eliminated. | | | | Bluetooth has been designed to operate in noisy |
| A Bluetooth chip is designed to replace cables by | | | | radio frequency environments, and uses a fast |
| taking the information normally carried by the | | | | acknowledgement and a frequency-hopping |
| cable, and transmitting it at a special frequency to | | | | scheme to make the communications link robust, |
| a receiver Bluetooth chip, which will then give the | | | | communication-wise. Bluetooth radio modules |
| information received to the computer, phone | | | | avoid interference from other signals by hopping |
| whatever. | | | | to a new frequency after transmitting or |
| Bluetooth definitionso Piconet: Devices connected | | | | receiving a packet. |
| in an ad hoc fashion that is, not requiring | | | | Compared with other systems operating in the |
| predefinition and planning, as with a standard | | | | same frequency band, the Bluetooth radio |
| network. Two to eight devices can be networked | | | | typically hops faster and uses shorter packets. |
| into a piconet. It is a peer network that is, once | | | | This is because short packages and fast hopping |
| connected each device has equal access to the | | | | limit the impact of microwave ovens and other |
| others. However, one device is defined as master, | | | | sources of disturbances. Use of Forward Error |
| and the others as slaves.o Scatternet: Several | | | | Correction (FEC) limits the impact of random noise |
| piconets may form a larger scatternet, with each | | | | on long-distance links. |
| piconet maintaining independence.o Master unit: | | | | Establishing network connections |
| The master in a piconet whose clock and hopping | | | | In order to establish new connections the |
| sequence synchronizes the other devices.o Slave | | | | procedures inquiry and paging are used. The |
| unit: Devices in a piconet that are not the | | | | inquiry procedure enables a unit to discover which |
| master.o MAC address: Three bit address that | | | | units are in range, and what their device |
| distinguishes each unit in a piconet.o Parked units: | | | | addresses and clocks are. With the paging |
| Piconet devices that are synchronized but don't | | | | proce-dure, an actual connection can be |
| have MAC addresses.o Sniff and hold mode: | | | | established. Only the Bluetooth device address is |
| Power-saving mode of a piconet device. | | | | required to set up a connection. Knowledge about |
| Overview of Bluetooth characteristics | | | | the clock will accelerate the setup procedure. A |
| These are the features of the Bluetooth | | | | unit that establishes a connection will carry out a |
| technology: | | | | page procedure and will automatically become the |
| 1. It separates the frequency band into hops. This | | | | master of the connection. |
| spread spectrum is used to hop from one channel | | | | For the paging process, several paging schemes |
| to another, which adds a strong layer of security. | | | | can be applied. There is one mandatory paging |
| 2. Up to eight devices can be networked in a | | | | scheme which has to be supported by each |
| piconet. | | | | Bluetooth device. This mandatory scheme is used |
| 3. Signals can be transmitted through walls and | | | | when units meet for the first time, and in case |
| briefcases, thus eliminating the need for | | | | the paging process directly follows the inquiry |
| line-of-sight. | | | | process. Two units, once connected using a |
| 4. Devices do not need to be pointed at each | | | | mandatory paging/scanning scheme, may agree |
| other, as signals are omni-directional. | | | | on an optional paging/scanning scheme. |
| 5. Both synchronous and asynchronous applications | | | | What kind of traffic can Bluetooth handle? |
| are supported, making it easy to implement on a | | | | Bluetooth is specifically designed to provide |
| variety of devices and for a variety of services, | | | | low-cost, robust, efficient, high capacity, ad hoc |
| such as voice and Internet. | | | | voice and data networking with the following |
| 6. Governments worldwide regulate it, so it is | | | | characteristics: |
| possible to utilize the same standard wherever | | | | 1. 1 Mb/sec. transmission/reception rate exploits |
| one travels. | | | | maximum available channel bandwidth. |
| How could Bluetooth be used? | | | | 2. Fast frequency hopping avoids interference. |
| Well, it's very much up to our imagination. But the | | | | 3. Adaptive output power minimizes interference. |
| ambition is set high, indeed; practically all | | | | 4. Short data packets maximize capacity during |
| computerized equipment normally found in a | | | | interference. |
| modern office (and home) which do not use a | | | | 5. Fast acknowledge allows low coding overhead |
| synchronous communications protocol could be | | | | for links. |
| adapted for use with Bluetooth. | | | | 6. CVSD (Continuous Variable Slope Delta |
| Check this list: | | | | Modulation) voice coding enables operation at high |
| Phones and pagers, Modems, LAN access devices, | | | | bit-error rates. |
| Headsets, Notebook computers, | | | | 7. Flexible packet types supports a wide |
| Desktop and handheld computers, Printers, Fax | | | | application range. |
| machines, Keyboards, Joysticks etc | | | | 8. Relaxed link budget supports low-cost single |
| Virtually any digital device can be part of the | | | | chip integration. |
| Bluetooth system. Bluetooth radio technology can | | | | 9. Transmission/reception interface tailored to |
| also provide a universal bridge to existing data | | | | minimize electric current consumption |
| networks, a peripheral interface, and a mechanism | | | | What about Bluetooth's security? |
| to form small ad hoc groupings of connected | | | | Security can mean two things in this context:o A) |
| devices, away from fixed network infrastructures. | | | | We want to be sure that transmitted data arrives |
| The dynamic connectivity-nature of Bluetooth | | | | in un-corrupted condition to the receiver.o B) We |
| makes it possible for this system to replace USB, | | | | also want to feel that this data has not been |
| and it is an improvement on | | | | eaves dropped by parties for whom it is not |
| Plug-and-Play-systems, where the operating | | | | intended. |
| system has to be rebooted for the installation to | | | | Both of these issues are (of course!) addressed |
| take effect. | | | | by Bluetooth. |
| Basic Bluetooth functions | | | | Safe transmission of data |
| The Bluetooth technology is quite complex. This is | | | | Are transmissions secure in a business and home |
| not so surprising, considering the task it has to | | | | environment? Yes, they are supposed to be quite |
| handle. It is mainly based on the IEEE 802.11 | | | | reliable. Bluetooth has built in sufficient encryption |
| standard, briefly described at right. Of the 2 | | | | and authentication and is thus very secure in any |
| network modes described, Bluetooth uses the | | | | environment. In addition to this, a |
| ad-hoc mode. This means that each station must | | | | frequency-hopping scheme with 1600 hops/sec. is |
| observe "netiqette" and give all other units fair | | | | employed. This is far quicker than any other |
| access to the wireless media. | | | | competing system. This, together with an |
| The IEEE 802.11 communications standard defines | | | | automatic output power adoption to reduce the |
| the protocol for two types of networks; Ad-hoc | | | | range exactly to requirement, makes the system |
| and client/server. | | | | extremely difficult to eavesdrop. |
| The Ad-hoc network is a simple network where | | | | |