18-06-2012, 06:08 PM
Bluetooth Based Smart Sensor Networks
Bluetooth Based Smart Sensor Networks.docx (Size: 92.65 KB / Downloads: 36)
INTRODUCTION
Bluetooth is a proprietary open wireless technology standard for exchanging data over short distances (using short wavelength radio transmissions in the ISM band from 2400-2480 MHz) from fixed and mobile devices, creating personal area networks (PANs) with high levels of security. Created by telecoms vendor Ericsson in 1994 it was originally conceived as a wireless alternative to RS-232 data cables. It can connect several devices, overcoming problems of synchronization. Bluetooth is managed by the Bluetooth Special Interest Group, which has more than 15,000 member companies in the areas of telecommunication, computing, networking, and consumer electronics. The SIG oversees the development of the specification, manages the qualification program, and protects the trademarks.
To be marketed as a Bluetooth device, it must be qualified to standards defined by the SIG. A network of patents is required to implement the technology and is only licensed to those qualifying devices; thus the protocol, whilst open, may be regarded as proprietary. The communications capability of devices and continuous transparent information routes are indispensable components of future oriented automation concepts. Communication is increasing rapidly in industrial environment even at field level. In any industry the process can be realized through sensors and can be controlled through actuators. The process is monitored on the central control room by getting signals through a pair of wires from each field device in Distributed Control Systems (DCS).
With advent in networking concept, the cost of wiring is saved by networking the field devices. But the latest trend is elimination of wires i.e., wireless networks. Wireless sensor networks -networks of small devices equipped with sensors, microprocessor and wireless communication interfaces. The word "Bluetooth" is an anglicized version of the Scandinavian Blåtand/Blåtann, the epithet of the tenth-century king Harald I of Denmark and parts of Norway who united dissonant Danish tribes into a single kingdom. The implication is that Bluetooth does the same with communications protocols, uniting them into one universal standard. In 1994, Ericsson Mobile communications, the global telecommunication company based in Sweden, initiated a study to investigate, the feasibility of a low power, low cost ratio interface, and to find a way to eliminate cables between devices.
Finally, the engineers at the Ericsson named the new wireless technology as “Blue tooth” to honor the 10th century king if Denmark, Harald Blue tooth (940 to 985 A.D).The goals of blue tooth is unification and harmony as well, specifically enabling different devices to communicate through a commonly accepted standard for wireless connectivity. We can distinguish two types of radio components for sensor nodes: those based on fixed frequency carriers, i.e., all sensor nodes within communication range compete for a shared channel in order to transmit data, and those based on spread-spectrum transmissions such as Bluetooth, i.e., sensor nodes within communication range use separate channels to transmit data. Roughly, the former type of radio favors connectionless data broadcast while the latter favors connection oriented communications. In this paper, we focus on the use of Bluetooth modules as radio components for sensor nodes Blue tooth operates in the unlicensed ISM band at 2.4 GHZ frequency band and use frequency hopping spread spectrum technique.
A typical Blue tooth device has a range of about 10 meters and can be extended to 100meters. Communication channels support total bandwidth of 1 Mb / sec. A single connection supports a maximum asymmetric data transfer rate of 721 KBPS maximum of three channels. Bluetooth was initially designed as a cable replacement technology. Does it make sense to consider it in the context of sensor networks? Spread spectrum radios are serious candidates for sensor network usage because of their resilience to interferences (notably in the free 2.4 GHz band). The WINS prototypes from UCLA, for instance, relied on this type of radio. The mass production of Bluetooth radios ensures robustness and decreasing costs Bluetooth modules are thus valid candidates, but how suited are they to the sensor network regime?
BLUETOOTH-NETWORKS
In Bluetooth, a Piconet is a collection of up to 8 devices that frequency hop together. Each Piconet has one master usually a device that initiated establishment of the Piconet, and up to 7 slave devices. Master’s Blue tooth address is used for definition of the frequency hopping sequence. Slave devices use the master’s clock to synchronize their clocks to be able to hop simultaneously.
A Piconet
The original piconet was a networking type used on RM Nimbus computers. These days, a piconet' is an ad-hoc computer network linking a user group of devices using Bluetooth technology protocols to allow one master device to interconnect with up to seven active slave devices (because a three-bit MAC address is used). Up to 255 further slave devices can be inactive, or parked, which the master device can bring into active status at any time. Piconet range will vary according to the class of the Bluetooth device. Data transfer rates vary between about 200 and 2100 Kbit/s at the application.
A Scatternet
A scatternet is a type of ad-hoc computer network consisting of two or more piconets. Both of the terms 'scatternet' and 'piconet' are typically applied to Bluetooth wireless technology. A piconet is the type of connection that is formed between two or more Bluetooth-enabled devices such as modern cell phones or PDAs. Bluetooth enabled devices are "peer units" in that they are able to act as either master or slave. However, when a piconet is formed between two or more devices, one device takes the role of 'master', and all other devices assume a 'slave' role for synchronization reasons. Piconets have a 3-bit address space, which limits the maximum size of a piconet to 8 devices (23 = 8), i.e. 1 master and 7 slaves.
A scatternet is a number of interconnected piconets that supports communication between more than 8 devices. Scatternets can be formed when a member of one piconet (either the master or one of the slaves) elects to participate as a slave in a second, separate piconet. The device participating in both piconets can relay data between members of both ad-hoc networks. However, the basic Bluetooth protocol does not support this relaying - the host software of each device would need to manage it. Using this approach, it is possible to join together numerous piconets into a large scatternet, and to expand the physical size of the network beyond Bluetooth's limited range.
Scatternet Formation Algorithms
We now review the localized scatternet formation algorithms from [1], based on sparse geometrical structures. The algorithms have several phases which are shown in following algorithm
Algorithm 1: Scatternet Formation Algorithms
Bluetooth Based Smart Sensor Networks.docx (Size: 92.65 KB / Downloads: 36)
INTRODUCTION
Bluetooth is a proprietary open wireless technology standard for exchanging data over short distances (using short wavelength radio transmissions in the ISM band from 2400-2480 MHz) from fixed and mobile devices, creating personal area networks (PANs) with high levels of security. Created by telecoms vendor Ericsson in 1994 it was originally conceived as a wireless alternative to RS-232 data cables. It can connect several devices, overcoming problems of synchronization. Bluetooth is managed by the Bluetooth Special Interest Group, which has more than 15,000 member companies in the areas of telecommunication, computing, networking, and consumer electronics. The SIG oversees the development of the specification, manages the qualification program, and protects the trademarks.
To be marketed as a Bluetooth device, it must be qualified to standards defined by the SIG. A network of patents is required to implement the technology and is only licensed to those qualifying devices; thus the protocol, whilst open, may be regarded as proprietary. The communications capability of devices and continuous transparent information routes are indispensable components of future oriented automation concepts. Communication is increasing rapidly in industrial environment even at field level. In any industry the process can be realized through sensors and can be controlled through actuators. The process is monitored on the central control room by getting signals through a pair of wires from each field device in Distributed Control Systems (DCS).
With advent in networking concept, the cost of wiring is saved by networking the field devices. But the latest trend is elimination of wires i.e., wireless networks. Wireless sensor networks -networks of small devices equipped with sensors, microprocessor and wireless communication interfaces. The word "Bluetooth" is an anglicized version of the Scandinavian Blåtand/Blåtann, the epithet of the tenth-century king Harald I of Denmark and parts of Norway who united dissonant Danish tribes into a single kingdom. The implication is that Bluetooth does the same with communications protocols, uniting them into one universal standard. In 1994, Ericsson Mobile communications, the global telecommunication company based in Sweden, initiated a study to investigate, the feasibility of a low power, low cost ratio interface, and to find a way to eliminate cables between devices.
Finally, the engineers at the Ericsson named the new wireless technology as “Blue tooth” to honor the 10th century king if Denmark, Harald Blue tooth (940 to 985 A.D).The goals of blue tooth is unification and harmony as well, specifically enabling different devices to communicate through a commonly accepted standard for wireless connectivity. We can distinguish two types of radio components for sensor nodes: those based on fixed frequency carriers, i.e., all sensor nodes within communication range compete for a shared channel in order to transmit data, and those based on spread-spectrum transmissions such as Bluetooth, i.e., sensor nodes within communication range use separate channels to transmit data. Roughly, the former type of radio favors connectionless data broadcast while the latter favors connection oriented communications. In this paper, we focus on the use of Bluetooth modules as radio components for sensor nodes Blue tooth operates in the unlicensed ISM band at 2.4 GHZ frequency band and use frequency hopping spread spectrum technique.
A typical Blue tooth device has a range of about 10 meters and can be extended to 100meters. Communication channels support total bandwidth of 1 Mb / sec. A single connection supports a maximum asymmetric data transfer rate of 721 KBPS maximum of three channels. Bluetooth was initially designed as a cable replacement technology. Does it make sense to consider it in the context of sensor networks? Spread spectrum radios are serious candidates for sensor network usage because of their resilience to interferences (notably in the free 2.4 GHz band). The WINS prototypes from UCLA, for instance, relied on this type of radio. The mass production of Bluetooth radios ensures robustness and decreasing costs Bluetooth modules are thus valid candidates, but how suited are they to the sensor network regime?
BLUETOOTH-NETWORKS
In Bluetooth, a Piconet is a collection of up to 8 devices that frequency hop together. Each Piconet has one master usually a device that initiated establishment of the Piconet, and up to 7 slave devices. Master’s Blue tooth address is used for definition of the frequency hopping sequence. Slave devices use the master’s clock to synchronize their clocks to be able to hop simultaneously.
A Piconet
The original piconet was a networking type used on RM Nimbus computers. These days, a piconet' is an ad-hoc computer network linking a user group of devices using Bluetooth technology protocols to allow one master device to interconnect with up to seven active slave devices (because a three-bit MAC address is used). Up to 255 further slave devices can be inactive, or parked, which the master device can bring into active status at any time. Piconet range will vary according to the class of the Bluetooth device. Data transfer rates vary between about 200 and 2100 Kbit/s at the application.
A Scatternet
A scatternet is a type of ad-hoc computer network consisting of two or more piconets. Both of the terms 'scatternet' and 'piconet' are typically applied to Bluetooth wireless technology. A piconet is the type of connection that is formed between two or more Bluetooth-enabled devices such as modern cell phones or PDAs. Bluetooth enabled devices are "peer units" in that they are able to act as either master or slave. However, when a piconet is formed between two or more devices, one device takes the role of 'master', and all other devices assume a 'slave' role for synchronization reasons. Piconets have a 3-bit address space, which limits the maximum size of a piconet to 8 devices (23 = 8), i.e. 1 master and 7 slaves.
A scatternet is a number of interconnected piconets that supports communication between more than 8 devices. Scatternets can be formed when a member of one piconet (either the master or one of the slaves) elects to participate as a slave in a second, separate piconet. The device participating in both piconets can relay data between members of both ad-hoc networks. However, the basic Bluetooth protocol does not support this relaying - the host software of each device would need to manage it. Using this approach, it is possible to join together numerous piconets into a large scatternet, and to expand the physical size of the network beyond Bluetooth's limited range.
Scatternet Formation Algorithms
We now review the localized scatternet formation algorithms from [1], based on sparse geometrical structures. The algorithms have several phases which are shown in following algorithm
Algorithm 1: Scatternet Formation Algorithms