BLUETOOTH

ABSTRACT:

Bluetooth wireless technology is a short-range communications technology intended to replace the cables connecting portable and/or fixed devices while maintaining high levels of security. The key features of Bluetooth technology are robustness, low power, and low cost. The Bluetooth specification defines a uniform structure for a wide range of devices to connect and communicate with each other.
Bluetooth technology has achieved global acceptance such that any Bluetooth enabled device, almost everywhere in the world, can connect to other Bluetooth enabled devices in proximity. Bluetooth enabled electronic devices connect and communicate wirelessly through short-range, ad hoc networks known as piconets. Each device can simultaneously communicate with up to seven other devices within a single piconet. Each device can also belong to several piconets simultaneously. Piconets are established dynamically and automatically as Bluetooth enabled devices enter and leave radio proximity.
A fundamental Bluetooth wireless technology strength is the ability to simultaneously handle both data and voice transmissions. This enables users to enjoy variety of innovative solutions such as a hands-free headset for voice calls, printing and fax capabilities, and synchronizing PDA, laptop, and mobile phone applications to name a few.

Introduction
The name Bluetooth is derived from the cognomen of a 10th century king, Harald Bluetooth King of Denmark and Norway from 935 and 936 respectively, to 940. He is known for his unification of previously warring tribes from Denmark (including Scania, present-day Sweden, where the Bluetooth technology was invented) and Norway. Bluetooth likewise was intended to unify different technologies like computers and mobile phones. The name may have been inspired less by the historical Harald than the loose interpretation of him in The Long Ships by Frans Gunnar Bengtsson, a Swedish best-selling Viking-inspired novel. The Bluetooth logo merges the Nordic runes analogous to the modern Latin H and B: (Haglaz) and (Berkanan). The logo is similar to an older logo for Beauknit Textiles, a division of Beauknit Corporation. That logo, using the connection of a reversed K and B for Beauknit, is wider and has rounded corners, but is otherwise the same.
Bluetooth wireless technology is a short-range communications technology intended to replace the cables connecting portable and/or fixed devices while maintaining high levels of security. The key features of Bluetooth technology are robustness, low power, and low cost. The Bluetooth specification defines a uniform structure for a wide range of devices to connect and communicate with each other.
Bluetooth technology has achieved global acceptance such that any Bluetooth enabled device, almost everywhere in the world, can connect to other Bluetooth enabled devices in proximity. Bluetooth enabled electronic devices connect and communicate wirelessly through short-range, ad hoc networks known as piconets. Each device can simultaneously communicate with up to seven other devices within a single piconet. Each device can also belong to several piconets simultaneously. Piconets are established dynamically and automatically as Bluetooth enabled devices enter and leave radio proximity.
A fundamental Bluetooth wireless technology strength is the ability to simultaneously handle both data and voice transmissions. This enables users to enjoy variety of innovative solutions such as a hands-free headset for voice calls, printing and fax capabilities, and synchronizing PDA, laptop, and mobile phone applications to name a few.
Specification Make-UpUnlike many other wireless standards, the Bluetooth wireless specification gives product developers both link layer and application layer definitions, which supports data and voice applications.
SpectrumBluetooth technology operates in the unlicensed industrial, scientific and medical (ISM) band at 2.4 to 2.485 GHz, using a spread spectrum, frequency hopping, full-duplex signal at a nominal rate of 1600 hops/sec. The 2.4 GHz ISM band is available and unlicensed in most countries.
InterferenceBluetooth technology’s adaptive frequency hopping (AFH) capability was designed to reduce interference between wireless technologies sharing the 2.4 GHz spectrum. AFH works within the spectrum to take advantage of the available frequency. This is done by detecting other devices in the spectrum and avoiding the frequencies they are using. This adaptive hopping allows for more efficient transmission within the spectrum, providing users with greater performance even if using other technologies along with Bluetooth technology. The signal hops among 79 frequencies at 1 MHz intervals to give a high degree of interference immunity.
RangeThe operating range depends on the device class:
· Class 3 radios – have a range of up to 1 meter or 3 feet
· Class 2 radios – most commonly found in mobile devices – have a range of 10 meters to 30 feet
· Class 1 radios – used primarily in industrial use cases – have a range of 100 meters or 300 feet
· PowerThe most commonly used radio is Class 2 and uses 2.5 mW of power. Bluetooth technology is designed to have very low power consumption. This is reinforced in the specification by allowing radios to be powered down when inactive.
Data Rate1 Mbps for Version 1.2; Up to 3 Mbps supported for Version 2.0 + EDR
Why Choose Bluetooth wireless technology?Bluetooth wireless technology is the simple choice for convenient, wire-free, short-range communication between devices. It is a globally available standard that wirelessly connects mobile phones, portable computers, cars, stereo headsets, MP3 players, and more. Thanks to the unique concept of “profiles,” Bluetooth enabled products do not need to install driver software. The technology is now available in its fourth version of the specification and continues to develop, building on its inherent strengths — small-form factor radio, low power, low cost, built-in security, robustness, ease-of-use, and ad hoc networking abilities. Bluetooth wireless technology is the leading and only proven short-range wireless technology on the market today shipping over five million units every week with an installed base of over 500 million units at the end of 2005.
Globally AvailableThe Bluetooth wireless technology specification is available free-of-charge to our member companies around the globe. Manufacturers from many industries are busy implementing the technology in their products to reduce the clutter of wires, make seamless connections, stream stereo audio, transfer data or carry voice communications. Bluetooth technology operates in the 2.4 GHz, one of the unlicensed industrial, scientific, medical (ISM) radio bands. As such, there is no cost for the use of Bluetooth technology. While you must subscribe to a cellular provider to use GSM or CDMA, with Bluetooth technology there is no cost associated with the use beyond the cost of your device.
Range of DevicesBluetooth technology is available in an unprecedented range of applications from mobile phones to automobiles to medical devices for use by consumers, industrial markets, enterprises, and more. The low power consumption, small size and low cost of the chipset solution enables Bluetooth technology to be used in the tiniest of devices. Have a look at the wide range products made available by our members in the Bluetooth product directory and the component product listing.
Ease of UseBluetooth technology is an ad hoc technology that requires no fixed infrastructure and is simple to install and set up. You don’t need wires to get connected. The process for a new user is easy – you get a Bluetooth branded product, check the profiles available and connect it to another Bluetooth device with the same profiles. The subsequent PIN code process is as easy as when you identify yourself at the ATM machine. When out-and-about, you carry your personal area network (PAN) with you and can even connect to others.
Globally Accepted SpecificationBluetooth wireless technology is the most widely supported, versatile, and secure wireless standard on the market today. The globally available qualification program tests member products as to their accordance with the standard. Since the first release of the Bluetooth specification in 1999, over 4000 companies have become members in the Bluetooth Special Interest Group (SIG). Meanwhile, the number of Bluetooth products on the market is multiplying rapidly. Volumes have doubled for the fourth consecutive year and are likely to reach an installed base of 500 million units by the close of 2005.
Secure ConnectionsFrom the start, Bluetooth technology was designed with security needs in mind. Since it is globally available in the open 2.4 GHz ISM band, robustness was built in from the beginning. With adaptive frequency hopping (AFH), the signal “hops” and thus limits interference from other signals. Further, Bluetooth technology has built-in security such as 128bit encryption and PIN code authentication. When Bluetooth products identify themselves, they use the PIN code the first time they connect. Once connected, always securely connected
Bluetooth Technology
The foundation of Bluetooth wireless technology is composed of the adopted specifications that are utilized and developed by the Bluetooth SIG’s global membership as guidelines for producing interoperable products. The Bluetooth specifications are categorized as the core specification, profiles, protocols, and transports.
The Bluetooth core specification describes the protocol stack up through the L2CAP layer and the characteristics of each of the relevant protocols, as well as the relationship between them.
Above the Bluetooth core specification are a set of protocols that have been defined for use by one or more profiles.
Profile specifications define a set of features required to support a particular usage model or set of usage models. A profile specification document describes how to use the protocol stack to implement a given profile.
Transport specifications define physical interfaces that can be used to implement the Host Controller Interface (HCI). The HCI transports are used in products that choose to separate the implementation of the Host and Controller functions.

Comparision with Other Technologies


The wireless world continues to grow as engineers develop faster, more robust technologies to free us from wires for greater simplicity, convenience, and efficiency. From short range to long range, the wireless landscape has taken shape in our lives. Bluetooth wireless technology, though one among many, has a wide variety of applications. A comparison of Bluetooth technology with other technologies is helpful then deciding which technologies to implement or products to purchase.
Bluetooth Wireless Technology
· Bluetooth wireless technology is geared towards voice and data applications
· Bluetooth wireless technology operates in the unlicensed 2.4 GHz spectrum
· Bluetooth wireless technology can operate over a distance of 10 meters or 100 meters depending on the Bluetooth device class. The peak data rate with EDR is 3 Mbps
· Bluetooth wireless technology is able to penetrate solid objects
· Bluetooth technology is omni-directional and does not require line-of-sight positioning of connected devices
· Security has always been and continues to be a priority in the development of the Bluetooth specification. The Bluetooth specification allows for three modes of security
· The cost of Bluetooth chips is under $3
Wi-Fi (IEEE 802.11)
Bluetooth technology costs a third of Wi-Fi to implement
· Bluetooth technology uses a fifth of the power of Wi-Fi
· The Wi-Fi Alliance tests and certifies 802.11 based wireless equipment
· 802.11a: This uses OFDM, operates in the 5 GHz range, and has a maximum data rate of 54 Mbps
· 802.11b: Operates in the 2.4 GHz range, has a maximum data rate of 11 Mbps and uses DSSS. 802.11b is the original Wi-Fi standard
· 802.11g: Operates in the 2.4 GHz range, uses OFDM and has a maximum data rate of 54 Mbps. This is backwards compatible with 802.11b
· 802.11e: This standard will improve quality of service
· 802.11h: This standard is a supplement to 802.11a in Europe and will provide spectrum and power control management. Under this standard, dynamic frequency selection (FS) and transmit power control (TPC) are added to the 802.11a specification
· 802.11i: This standard is for enhanced security. It includes the advanced encryption standard (AES). This standard is not completely backwards compatible and some users will have to upgrade their hardware. The full 802.11i support is also referred to as WPA2
· 802.11k: Under development, this amendment to the standard should allow for increased radio resource management on 802.11 networks
· 802.11n: This standard is expected to operate in the 5 GHz range and offer a maximum data rate of over 100 Mbps (though some proposals are seeking upwards of 500 Mbps). 802.11n will handle wireless multimedia applications better than the other 802.11 standards
· 802.11p: This standard will operate in the automotive-allocated 5.9 GHz spectrum. It will be the basis for the dedicated short range communications (DSRC) in North America. The DSRC will allow vehicle to vehicle and vehicle to roadside infrastructure communication
· 802.11r: This amendment to the standard will improve users’ ability to roam between access points or base stations. The task group developing this form in spring/summer 2004
· 802.11s: Under development, this amendment to the standard will allow for mesh networking on 802.11 networks. The task group developing this formed in spring/summer 2004
WiMAX (Worldwide Interoperability for Microwave Access and IEEE 802.16)
· WiMax is a wireless metropolitan area network (MAN) technology
· WiMax has a range of 50 km with data rates of 70 Mbps. Typical cell has a shorter range
· The original 802.16 standard operated in the 10-66 GHz frequency bands with line of sight environments
· The newly completed 802.16a standard operates between 2 and 11 GHz and does not need line of sight
· Delays in regulatory approval in Europe due to issues regarding the use of the spectrums in the 2.8 GHz and 3.4 GHz range
· Supports vehicle mobility for between 20 to 100+ km/hr. The 802.16e standard will allow nomadic portability
· The IEEE 802.16a and the ETSI HIPERMAN (High Performance Radio Metropolitan Area Network) share the same PHY and MAC. 802.16 has been designed from the beginning to be compatible with the European standard
· Created to compete with DSL and cable modem access, the technology is considered ideal for rural, hard to wire areas
WiBro (Wireless Broadband)
· Portable Internet Service (WiBro) is to provide a high data rate wireless internet access with PSS (Personal Subscriber Station) under the stationary or mobile environment, anytime and anywhere. Primarily based in South Korea based on TTA specifications.
· 2300-2400 MHz, TDD, OFDMA, channel bandwidth 10 MHz, etc.
· System shall support mobile users at a velocity of up to 60km/h
· Throughput (per user) Max. DL / UL = 3 / 1 [Mbps], Min. DL / UL = 512 / 128 [Kbps]
· Will come online Q1 2006
Infrared (IrDA)
· IrDA is used to provide wireless connectivity for devices that would normally use cables to connect. IrDA is a point-to-point, narrow angle (30° cone), ad-hoc data transmission standard designed to operate over a distance of 0 to 1 meter and at speeds of 9600 bps to 16 Mbps
· IrDA is not able to penetrate solid objects and has limited data exchange applications compared to other wireless technologies
· IrDA is mainly used in payment systems, in remote control scenarios or when synchronizing two PDAs with each other
Radio Frequency Identification (RFID)
· There are over 140 different ISO standards for RFID for a broad range of applications
· With RFID, a passive or unpowered tag can be powered at a distance by a reader device. The receiver, which must be within a few feet, pulls information off the ‘tag,’ and then looks up more information from a database. Alternatively, some tags are self-powered, ‘active’ tags that can be read from a greater distance
· RFID can operate in low frequency (less than 100 MHz), high frequency (more than 100 MHz), and UHF (868 to 954 MHz)
· Uses include tracking inventory both in shipment and on retail shelves
802.20
· Considered to be mobile wireless broadband wireless access.
· Maximum data rate expected to be 1 Mbps, operating in licensed bands below 3.5 GHz
· Supports vehicle mobility up to 250 km/hr

Security
Today's wireless world means that data is being sent, among us, invisibly from device to device, country to country, person to person. This data, in the form of e-mails, photos, contacts and addresses are precious and private to each of us. This private information, no longer making its way along wires in plain sight, needs to be sent securely to its intended recipient without interception. Wireless standards the world over are evolving and have various formats for dealing with the security issues of its users. Bluetooth wireless technology is no exception.Bluetooth wireless technology has, from its inception, put great emphasis on wireless security so that users of this global standard can feel secure while making their connections. The Bluetooth Special Interest Group (SIG), made up of over 4000 member manufacturers, has a Bluetooth security experts group made up of engineers from its member companies who provide critical security information and feedback that is taken into account as the Bluetooth wireless specification evolves.
Product developers that use Bluetooth wireless technology in their products have several options for implementing security. There are three modes of security for Bluetooth access between two devices. Security Mode 1: non-secure Security Mode 2: service level enforced security Security Mode 3: link level enforced securityThe manufacturer of each product determines these security modes. Devices and services also have different security levels. For devices, there are two levels: "trusted device" and "untrusted device." A trusted device, having been paired with one's other device, has unrestricted access to all services.With regard to services, three security levels are defined: services that require authorization and authentication, services that require authentication only and services that are open to all devices.Lately, confusion and misinformation surrounding security and Bluetooth wireless technology has increased. The current security issues typically involve mobile phones. How these issues apply to other classes of devices is important and is often not addressed. The encryption algorithm in the Bluetooth specifications is secure. This includes devices such as mice and keyboards connecting to a PC, a mobile phone synchronizing with a PC, and a PDA using a mobile phone as a modem to name just a few of the many use cases.Cases where data has been compromised on mobile phones are the result of implementation issues on that platform. The Bluetooth SIG diligently works with our members to investigate any issues that are reported to understand the root cause of the issue. If it is a specification issue, we work with the membership to get patches out and ensure future devices don't suffer from the same vulnerability. This is an on-going process. The recently reported issues of advanced "hackers" gaining access to information stored on select mobile phones using Bluetooth functionality are due to incorrect implementation. The names bluesnarfing and bluebugging have been given to these methods of illegal and improper access to information. The questions and answers below provide users with more information about these current issues and will address their concerns for dealing with these security risks.
List of applications
· Wireless control of and communication between a cell phone and a hands free headset or car kit. This was one of the earliest applications to become popular.
· Wireless networking between PCs in a confined space and where little bandwidth is required.
· Wireless communications with PC input and output devices, the most common being the mouse, keyboard and printer.
· Transfer of files between devices via OBEX.
· Transfer of contact details, calendar appointments, and reminders between devices via OBEX.
· Replacement of traditional wired serial communications in test equipment, GPS receivers and medical equipment.
· For controls where infrared was traditionally used.
· Sending small advertisements from Bluetooth enabled advertising hoardings to other, discoverable, Bluetooth devices.
· Wireless control of a games console – Nintendo's Wii and Sony's PlayStation 3 both use Bluetooth technology for their wireless controllers.
Hackers of Bluetooth
BluejackingBluejacking allows phone users to send business cards anonymously using Bluetooth wireless technology. Bluejacking does NOT involve the removal or alteration of any data from the device. These business cards often have a clever or flirtatious message rather than the typical name and phone number. Bluejackers often look for the receiving phone to ping or the user to react. They then send another, more personal message to that device. Once again, in order to carry out a bluejacking, the sending and receiving devices must be within 10 meters of one another. Phone owners who receive bluejack messages should refuse to add the contacts to their address book. Devices that are set in non-discoverable mode are not susceptible to bluejacking.
BluebuggingBluebugging allows skilled individuals to access the mobile phone commands using Bluetooth wireless technology without notifying or alerting the phone’s user. This vulnerability allows the hacker to initiate phone calls, send and receive text messages, read and write phonebook contacts, eavesdrop on phone conversations, and connect to the Internet. As with all the attacks, without specialized equipment, the hacker must be within a 10 meter range of the phone. This is a separate vulnerability from bluesnarfing and does not affect all of the same phones as bluesnarfing.
BluesnarfingBluesnarfing allows hackers to gain access to data stored on a Bluetooth enabled phone using Bluetooth wireless technology without alerting the phone’s user of the connection made to the device. The information that can be accessed in this manner includes the phonebook and associated images, calendar, and IMEI (international mobile equipment identity). By setting the device in non-discoverable, it becomes significantly more difficult to find and attack the device. Without specialized equipment the hacker must be within a 10 meter range of the device while running a device with specialized software. Only specific older Bluetooth enabled phones are susceptible to bluesnarfing.
Car WhispererThe car whisperer is a software tool developed by security researchers to connect to and send or receive audio to and from Bluetooth car-kits with a specific implementation. An individual using the tool could potentially remotely connect to and communicate with a car from an unauthorized remote device, sending audio to the speakers and receiving audio from the microphone in the remote device. Without specialized equipment, someone using the tool must be within a 10 meter range of the targeted car while running a laptop with the car whisperer tool. The security researchers’ goal was to highlight an implementation weakness in a select number of Bluetooth enabled car-kits and pressure manufacturers to better secure Bluetooth enabled devices.
Is Bluetooth wireless technology susceptible to hackers in other ways?Currently, the attacks listed on this page are the only known possibilities for hacking into a limited amount of products on the market, if appropriate measures are taken such as having security turned on and using reasonably long PIN codes or pairing devices in private. The Bluetooth SIG continues to study security risks associated with the technology and determine their viability as the technology spreads and develops.
What can consumers do to protect their data?Consumers can do a number of things to protect their data. If users have a phone that is vulnerable to bluesnarfing or bluebugging, they should contact the phone's manufacturer or take the phone to a manufacturer authorized service point. The manufacturers of the vulnerable devices have developed software patches to fix the vulnerability. In addition, if users are still concerned about a device being targeted, they can turn the device to non-discoverable mode when not using Bluetooth wireless technology and in unknown areas. Users can also ensure their data is secure by not "pairing" with unknown devices. If a user were to receive an invitation to pair with another device, and asked to put in a PIN code, but was unsure of what device was inviting to pair, the user should not pair. Only pair with known devices.
What is the cabir worm? Which devices does the cabir worm affect?The cabir worm is malicious software, also known as malware. When installed on a phone, it uses Bluetooth technology to send itself to other similarly vulnerable devices. Due to this self-replicating behavior, it is classified as a worm. The cabir worm currently only affects mobile phones that use the Symbian series 60 user interface platform and feature Bluetooth wireless technology. Furthermore, the user has to manually accept the worm and install the malware in order to infect the phone. More information on the cabir worm is available from the software licensing company Symbian and on the websites of F-Secure, McAfee and Symantec.
How does a PIN affect security?The personal identification number (PIN) is a four or more digit alphanumeric code that is temporarily associated with one's products for the purposes of a one time secure pairing. It is recommended that users employ at minimum an eight character or more alphanumeric PIN when possible. Product owners must share that PIN number only with trusted individuals and trusted products for pairing. Without this PIN number, pairing cannot occur. It is always advisable to pair products in areas with relative privacy. Avoid pairing your Bluetooth enabled devices in public. If, for some reason, your devices become unpaired, wait until you are in a secure, private location before repairing your devices.
Why does pairing in a public location potentially introduce a security risk?Theoretically a hacker can monitor and record activities in the frequency spectrum and then use a computer to regenerate the PIN codes being exchanged. This requires specially built hardware and thorough knowledge of Bluetooth systems. By using a PIN code with eight or more alphanumeric characters it would take the hacker years to discover the PIN. By using a four digit numeric PIN code, the hacker could discover the PIN in a matter of a few hours. Still advanced software is required.
What is denial of service (DoS)?The well known denial of service (DoS) attack, which has been most popular for attacking internet web sites and networks, is now an option for hackers of Bluetooth wireless technology enabled devices. This nuisance is neither original nor ingenious and is, very simply, a constant request for response from a hacker’s Bluetooth enabled computer (with specific software) to another Bluetooth enabled device such that it causes some temporary battery degradation in the receiving device. While occupying the Bluetooth link with invalid communication requests, the hacker can temporarily disable the product’s Bluetooth services.
What devices are vulnerable to attacks, and what is the Bluetooth SIG doing about it?DoS attacks can be performed on any discoverable Bluetooth enabled device but in some cases, advanced hackers can determine the address of a non-discoverable Bluetooth device. The Bluetooth SIG takes all security issues seriously, and we constantly work to make the specification more secure. Therefore, future Bluetooth core specifications are planned to include features that will make it impossible to penetrate non-discoverable devices. There are also ways for manufacturers to reduce the risk of DoS attacks at the implementation level of Bluetooth wireless technology.
What is the risk of being on the receiving end of a DoS attack?To date, DoS attacks on Bluetooth devices have only been conducted in laboratory tests. The risk of an attempted DoS attack should be considered minimal given the requirements and the normally short range of Bluetooth wireless technology.
Protecting your Bluetooth Devices
While Bluetooth wireless technology is fundamentally secure, keeping Bluetooth enabled devices secure is a team effort. The Bluetooth SIG, manufacturers, and you, the user, each has a role in ensuring the security of your Bluetooth enabled devices. As a user of Bluetooth enabled devices, you should understand the basics of securely using a PDA,
phone, etc. that can connect wirelessly to other consumer electronics.Bluetooth wireless technology has, from its inception, put great emphasis on wireless security so that users of this global standard can feel secure while making their connections. The Bluetooth Special Interest Group (SIG), made up of over 4000 member manufacturers, has a Bluetooth security experts group made up of engineers from its member companies, which provide critical security information and feedback that is taken into account as the Bluetooth wireless specification evolves. .
Future Trend
The next version of Bluetooth technology, currently code-named Lisbon, includes a number of features to increase security, usability and value of Bluetooth. The following features are defined:
· Automatic Encryption Change - allows encrypted links to change their encryption keys periodically, increasing security, and also allowing role switches on an encrypted link
· Extended Inquiry Response - provides more information during the inquiry procedure to allow better filtering of devices before connection. This information includes the name of the device, and a list of services, with other information.
· Sniff Subrating - reducing the power consumption when devices are in the sniff low-power mode, especially on links with asymmetric data flows. Human interface devices (HID) are expected to benefit the most, with mice and keyboards increasing the battery life from 3 to 10 times those currently used.
· QoS Improvements - these will enable audio and video data to be transmitted at a higher quality, especially when best effort traffic is being transmitted in the same piconet.
· Simple Pairing - this improvement will radically improve the pairing experience for Bluetooth devices, while at the same time increasing the use and strength of security. It is expected that this feature will significantly increase the use of Bluetooth.
· Bluetooth technology already plays a part in the rising Voice over IP (VOIP) scene, with Bluetooth headsets being used as wireless extensions to the PC audio system. As VOIP becomes more popular, and more suitable for general home or office users than wired phone lines, Bluetooth may be used in Cordless handsets, with a base station connected to the Internet link.
· The version of Bluetooth after Lisbon, code-named Seattle, has many of the same features, but is most notable for plans to adopt Ultra-wideband radio technology. This will allow Bluetooth use over UWB radio, enabling very fast data transfers, synchronizations and file pushes, while building on the very low power idle modes of Bluetooth. The combination of a radio using little power when no data is transmitted, and a high data rate radio used to transmit bulk data, could be the start of software radios. Bluetooth, given its worldwide regulatory approval, low power operation, and robust data transmission capabilities, provides an excellent signalling channel to enable the soft radio concept.