HOW DOES IT GET THAT NAME !!!
Bluetooth was borrowed from the 10th century, second King of Denmark, King Harald Bluetooth; who was famous for uniting Scandinavia just as we intended to unite the PC and cellular industries with a short-range wireless link.
OKAY BACK TO TECHNOLOGY ......................
Bluetooth is one of the most recent development in wireless technology.Bluetooth technology allows wireless connection between various communication devices with ease.The paper begins with a brief introduction of Bluetooth technology and the need for it.It then explains other two types of
wireless communication viz.Infrared communication and Cable Synchronization and the advantages of Bluetooth over these.It also explains the techniques by which Bluetooth avoids interference from other electronic devices.
Avoiding interference from other electronic devices : HOW IT HAPPENS !!!
Weak Transmission Of Signals :- One of the ways Bluetooth devices will avoid interfering with other systems is by sending out very weak signals of 1 milliwatt. By comparison, the most powerful cell phones can transmit a signal of 3 watts. The low power limits the range of a Bluetooth device to about 10 meters, cutting the chances of interference between your computer system and your portable telephone or television. Even with the low power, the walls in your house won't stop a Bluetooth signal, from controlling several devices in different rooms.
Spread-Spectrum Frequency Hopping :- With many different Bluetooth devices in a room, you might think they'd interfere with one another, but it's unlikely that several devices will be on the same frequency at the same time because Bluetooth uses a technique called spread-spectrum frequency hopping. In this technique, a device will use 79 individual randomly chosen frequencies within a designated range, changing from one to another on a regular basis. In the case of Bluetooth, the transmitters change frequencies 1,600 times every second, meaning that more devices can make full use of a limited slice of the radio spectrum. Since every Bluetooth transmitter uses spread-spectrum transmitting automatically, it’s unlikely that two transmitters will be on the same frequency at the same time. This same technique minimizes the risk that portable phones or baby monitors will disrupt Bluetooth devices since any interference on a particular frequency will last only a tiny fraction of a second.
When new Bluetooth-capable devices come within range of one another, an electronic conversation will take place to determine whether they have data to share or whether one needs to control the other. The user doesn't have to press a button or give a command -- the electronic conversation happens automatically. Once the conversation has occurred, the devices -- whether they're part of a computer system or a stereo -- form a network. Bluetooth systems create a Personal-Area Network (PAN) or "piconet" that may fill a room or may encompass no more distance than that between the cellphone on a belt-clip and the headset you're wearing. Once a piconet is established, the members randomly hop frequencies in unison so they stay in touch with one another and avoid other piconets that may be operating in the same room.
U WANT SOME EXAMPLE ???
Let’s take a look at how the Bluetooth frequency hopping and personal-area network keep systems from becoming confused. Let’s say you’ve got a typical modern living room with the typical modern stuff inside. There’s an entertainment system with a stereo, a DVD player, a satellite TV receiver and a television; a cordless telephone; and a personal computer. Each of these systems uses Bluetooth, and each forms its own piconet to talk between main unit and peripheral.
The cordless telephone has one Bluetooth transmitter in the base and another in the handset. The manufacturer has programmed each unit with an address that falls into a range of addresses it has established for a particular type of device. When the base is first turned on, it sends radio signals asking for a response from any units with an address in a particular range. Since the handset has an address in the range, it responds and a tiny network is formed. Now, even if one of these devices should receive a signal from another system, it will ignore it since it’s not from within its network. The computer and entertainment system go through similar routines, establishing networks among addresses in ranges established by manufacturers. Once the networks are established, the systems begin talking among themselves. Each piconet hops randomly through the available frequencies, so all of the piconets are completely separated from one another.
Now the living room has three separate networks established, each one made up of devices that know the address of transmitters it should listen to, and the address of receivers it should talk to. Since each network is changing the frequency of its operation thousands of times a second, it’s unlikely that any two networks will be on the same frequency at the same time. If it turns out that they are, then the resulting confusion will only cover a tiny fraction of a second, and software designed to correct for such errors will weed out the confusing information and get on with the network’s business.
Bluetooth was borrowed from the 10th century, second King of Denmark, King Harald Bluetooth; who was famous for uniting Scandinavia just as we intended to unite the PC and cellular industries with a short-range wireless link.
OKAY BACK TO TECHNOLOGY ......................
Bluetooth is one of the most recent development in wireless technology.Bluetooth technology allows wireless connection between various communication devices with ease.The paper begins with a brief introduction of Bluetooth technology and the need for it.It then explains other two types of
wireless communication viz.Infrared communication and Cable Synchronization and the advantages of Bluetooth over these.It also explains the techniques by which Bluetooth avoids interference from other electronic devices.
Avoiding interference from other electronic devices : HOW IT HAPPENS !!!
Weak Transmission Of Signals :- One of the ways Bluetooth devices will avoid interfering with other systems is by sending out very weak signals of 1 milliwatt. By comparison, the most powerful cell phones can transmit a signal of 3 watts. The low power limits the range of a Bluetooth device to about 10 meters, cutting the chances of interference between your computer system and your portable telephone or television. Even with the low power, the walls in your house won't stop a Bluetooth signal, from controlling several devices in different rooms.
Spread-Spectrum Frequency Hopping :- With many different Bluetooth devices in a room, you might think they'd interfere with one another, but it's unlikely that several devices will be on the same frequency at the same time because Bluetooth uses a technique called spread-spectrum frequency hopping. In this technique, a device will use 79 individual randomly chosen frequencies within a designated range, changing from one to another on a regular basis. In the case of Bluetooth, the transmitters change frequencies 1,600 times every second, meaning that more devices can make full use of a limited slice of the radio spectrum. Since every Bluetooth transmitter uses spread-spectrum transmitting automatically, it’s unlikely that two transmitters will be on the same frequency at the same time. This same technique minimizes the risk that portable phones or baby monitors will disrupt Bluetooth devices since any interference on a particular frequency will last only a tiny fraction of a second.
When new Bluetooth-capable devices come within range of one another, an electronic conversation will take place to determine whether they have data to share or whether one needs to control the other. The user doesn't have to press a button or give a command -- the electronic conversation happens automatically. Once the conversation has occurred, the devices -- whether they're part of a computer system or a stereo -- form a network. Bluetooth systems create a Personal-Area Network (PAN) or "piconet" that may fill a room or may encompass no more distance than that between the cellphone on a belt-clip and the headset you're wearing. Once a piconet is established, the members randomly hop frequencies in unison so they stay in touch with one another and avoid other piconets that may be operating in the same room.
U WANT SOME EXAMPLE ???
Let’s take a look at how the Bluetooth frequency hopping and personal-area network keep systems from becoming confused. Let’s say you’ve got a typical modern living room with the typical modern stuff inside. There’s an entertainment system with a stereo, a DVD player, a satellite TV receiver and a television; a cordless telephone; and a personal computer. Each of these systems uses Bluetooth, and each forms its own piconet to talk between main unit and peripheral.
The cordless telephone has one Bluetooth transmitter in the base and another in the handset. The manufacturer has programmed each unit with an address that falls into a range of addresses it has established for a particular type of device. When the base is first turned on, it sends radio signals asking for a response from any units with an address in a particular range. Since the handset has an address in the range, it responds and a tiny network is formed. Now, even if one of these devices should receive a signal from another system, it will ignore it since it’s not from within its network. The computer and entertainment system go through similar routines, establishing networks among addresses in ranges established by manufacturers. Once the networks are established, the systems begin talking among themselves. Each piconet hops randomly through the available frequencies, so all of the piconets are completely separated from one another.
Now the living room has three separate networks established, each one made up of devices that know the address of transmitters it should listen to, and the address of receivers it should talk to. Since each network is changing the frequency of its operation thousands of times a second, it’s unlikely that any two networks will be on the same frequency at the same time. If it turns out that they are, then the resulting confusion will only cover a tiny fraction of a second, and software designed to correct for such errors will weed out the confusing information and get on with the network’s business.
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