Bluetooth technology Archives

Bluetooth technology Archives

Bluetooth technology Archives

Bluetooth technology Archives

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October 16, 2009

Going the Distance with Wi-Fi Direct

By Glenn Fleishman

The areas Wi-Fi Direct can best Bluetooth are on distance and speed: I've written a few articles already about Wi-Fi Direct, the new peer-to-peer mode that the Wi-Fi Alliance is finalizing and which will appear in updated and new hardware in mid-2010. This includes my analysis of why Bluetooth and Wi-Fi Direct serve related but not entirely overlapping purposes. But in that discussion, I only mentioned speed and distance in passing.

Bluetooth devices come in one of three varieties by signal output: Class 1, 2, or 3. Class 3 devices (1 meter, 1mW) were originally the most common, intended for low-power earpiece-to-phone communication. Class 2 (10 meters, 2.5 mW) became more common, and I believe now predominates. This allows communication within a room and sometimes beyond. Class 1 (100 meters, 100 mW) is rarely found in peripherals, although it's used in computers. The Callpod Dragon V2 headset ($99) is a rare peripheral exception, but the size and price have something to do with its ability to push out that much signal.

Wi-Fi, in contrast, is designed for whole home/whole office coverage, with 802.11n finally achieving that for many venues. Wi-Fi equipment makers used to, and some still do, put out nominal distance numbers, like 100 meters diameter or what have you, but I always thought these numbers were nonsense. Originally, these distances were based on minimal testing in simulations of the real world. Some companies and trade groups have houses that are designed to be testbeds, even.

In practice, 802.11g Wi-Fi was a one to two wall and one, maybe two floor solution. A lot of factors about building materials affected that. 802.11n penetrates far better, and can produce a far clearer signal (and thus higher speeds) through many more obstructions.

For Wi-Fi Direct, where you want to be able to peer easily to devices around you without fuss, the distance and penetration issues may be one important component of why people may turn to use that mode rather than Bluetooth. It's possible that some operating system makers or third-party software developers will make it simple for Wi-Fi Direct to become an ad hoc Internet access mode, bypassing the need for guest networks in access points, for instance.

Speed will also be a component depending on the uses to which Wi-Fi Direct is put, and how OS makers and device makers incorporate the mode. If Apple lets me use Wi-Fi Direct on an iPhone to transfer data from an Apple TV or a Mac or Windows system with iTunes installed (say, as an extension of the firm's new Home Sharing feature in iTunes), then I will surely want the 50 to 150 Mbps available with Wi-Fi Direct instead of the 2 Mbps of throughput from Bluetooth 2.1+EDR.

This draws me back to the application and profile issue I discussed in the previous article on Bluetooth competition. The usage Wi-Fi Direct beyond simple file transfer and Internet access and printing will depend heavily on having layers of functionality (tasks and purposes) put on top of connectivity.

Posted by Glenn Fleishman at 10:55 AM | Permanent Link | Categories: Bluetooth, Standards|No Comments

October 14, 2009

Is Wi-Fi Gunning for Bluetooth? Not Precisely

By Glenn Fleishman

Wi-Fi Direct is both parallel to and complementary of Bluetooth. Discuss: Today's announcement of Wi-Fi Direct, a peer-to-peer Wi-Fi transfer method, might seem to be firing across Bluetooth's bow. But it isn't quite. Intel's My WiFi is a much more direct threat, and even then may not materialize in quite the way that's being predicted. (Read my coverage, "Wi-Fi Alliance Peers into the Future with Ad Hoc Replacement.")

To review, Bluetooth is a PAN (personal area networking) technology in which devices under the control of the same person or computer communicate over short ranges and relatively low speeds. Bluetooth can create peer-to-peer connections or piconet networks, which comprise a host and up to seven clients. In a very standard configuration, a cell phone might use Bluetooth to communicate with a laptop, sharing its 3G mobile broadband connection, while at the same time a Bluetooth earpiece is paired with the phone to handle audio.

Bluetooth requires a pairing process, in which devices authenticate to each other and agree through a handshake (with optional encryption) to talk to one another. The SIG, device makers, and desktop and mobile OS developers have done a great job of simplifying this process down to typically entering a PIN--one of several options with the current security system, Secure Simple Pairing--instead of having 20 to 25 steps as it used to be.

Bluetooth's current release (2.1+HDR [high data rate]) encompasses a wireless spec for 3 Mbps data transfer (raw) using the 2.4 GHz band. The spec also includes application-layer elements, which are called profiles, and which define a large array of end-to-end tasks, like printing, file transfer, or acting as a modem. This allows any manufacturer to make a Bluetooth keyboard that talks the HID (human interface device) profile, and which is tested and certified as such, to talk to any other Bluetooth device with the HID profile.

The Bluetooth SIG, which maintains and develops the spec, isn't tied to its physical medium. It's tried to partner with other specs in process to extend itself, notably tying its cart at one point to both major ultrawideband (UWB) encodings, and then picking WiMedia, which was the "winner" in UWB. WiMedia disbanded, but handed off the Bluetooth component to the SIG; there may still be life in it. (Originally, Intel et al. wanted to stick one UWB radio in computers and devices, but have many different protocols run over that radio, such as Bluetooth, TCP/IP, Wireless USB, and video. UWB is currently shipping only as an instantiation of Wireless USB.)

While UWB fiddled and burned, however, the SIG worked on Bluetooth 3.0+HS (High Speed), which incorporates a high-speed transfer mode that allows a Bluetooth device to coordinate with a peer switching to use 802.11 for a bulk transfer, useful for large files or high-speed video streaming. The session is still within the structure of a Bluetooth PAN, and the use of 802.11 is entirely under the control of the Bluetooth session. The devices don't suddenly become ad hoc nodes or soft access points. Note the use of 802.11: this is a particular use of that protocol outside of any current Wi-Fi spec.

Wi-Fi Direct is an outgrowth of the interest by Intel and others in reducing the number of radio technologies and the level of complexity in devices, which can correspondingly reduce battery usage, while also developing a spec that's to their liking. Intel has a board seat on the Wi-Fi Alliance and the Bluetooth SIG, but still enjoys charting its own course.

Wi-Fi Direct is a peer-to-peer technology, at least the way it's being described initially. Wi-Fi devices that have services to offer (like printing, file sharing, etc.) can advertise those in a way that other equipped devices can access directly. This new method offers the speed and security of an infrastructure Wi-Fi network with an access point at the center without the overhead of joining such a network or making such networks public to allow access to specific resources. That is, someone can print to your printer without you giving them a key to your network. Wi-Fi Direct is built on top of 802.11n, so it can work in both 2.4 and 5 GHz, too.

The simplicity of Wi-Fi Direct is supposed to aid in devices without keyboards or easy data entry methods, much as Wi-Fi Protected Setup (WPS) was supposed to offer a one-click secure connection. With a peer-to-peer approach, a camcorder could hook up with a laptop to transfer data directly without you needing to enter a WPA2 Personal passphrase or even connect at all to an existing Wi-Fi network.

Beyond speed and security, Wi-Fi Direct will allow an adapter to be scanning and accessing peers while also maintaining a full infrastructure connection to a network. It's this feature that allows devices to ostensibly cut the Bluetooth "cord," although I'm still dubious about that as a general element, as I'll explain.

The My WiFi technology that Intel developed (apparently at least in part with Ozmo Devices) emphasizes more of the PAN aspect, talking about having eight devices associated with a laptop, for instance.

So, the question at the outset was whether Wi-Fi Direct is a competitor to Bluetooth?

Bluetooth and Wi-Fi Direct definitely compete head to head on trying to make the simplest network connection between two devices for a variety of straightforward purposes.

However, Wi-Fi Direct won't be backward compatible to the hundreds of millions of devices on the market that already have Bluetooth 1.x or 2.x. Bluetooth's later flavors (2.x and 3.x) are backwards compatible with those older devices.

And while Wi-Fi with a PAN mode could reduce circuit counts, most Wi-Fi chips that are being sold in the mobile market, and I believe in the desktop/laptop market, are integrated Bluetooth/Wi-Fi modules that often throw in other radios and circuitry as well.

Wi-Fi may eventually be appropriate to build into keyboards, mice, wireless headsets, earpieces, and other low-battery peripherals, but that's not really the case today. Bluetooth dominates there in hundreds of millions of installed devices.

Bluetooth's profiles also seem like an advantage to me. Kelly Davis-Felner, the Wi-Fi Alliance's marketing director, said that Wi-Fi Direct would not have application or task overlays, but would be focused on the networking and communication level, as with other Wi-Fi certifications.

Which means that if I connect my mobile phone with my computer to transfer music over, I still need an application on both sides that handles the file transfer. With Bluetooth, the profiles still need an interface on top, but a universally supported file-transfer method already exists. I can use a Bluetooth program under Windows and on the Mac and within various mobile phones to transfer files today.

If I want a method that synchronizes stored files and handles it automatically, then OS makers or third-party developers still do have to build an application on top of that. But with Bluetooth, they can rely on leveraging a well-supported mechanism. It's asymmetric, in that a desktop OS program for syncing MP3 files or photos doesn't require a corresponding program to be installed on a mobile phone that allows access to its storage via the Bluetooth profile.

Now, of course, I'm being a little disingenuous about profiles, because Wi-Fi Direct will create an IP-based network between the two parties, allowing existing service discovery methods to work just as they do over a wireless LAN today--including Apple's Bonjour and whatever the current name of Microsoft's technology. But none of these methods are supported across gadgets (like cameras). mobile operating systems, and desktop/laptop operating system platforms. That's going to be the challenge for Wi-Fi Direct.

In the end, I certainly see Wi-Fi Direct as provoking additional industry efforts to figure out precisely what's useful about PANs and sell those capabilities to consumers as solutions for frustration or a way to accomplish tasks they're unaware they need to accomplish.

The best thing about Wi-Fi Direct is that it enables a secure, high-speed ad hoc mode that will actually work among different devices, something that's long been needed.

One of the most interesting aspects of Wi-Fi Direct is that it could be used with Bluetooth, since many manufacturers participate actively in the Bluetooth SIG and Wi-Fi Alliance. Beyond Bluetooth 3.0+HS, there could be a convergence path for hand-in-hand networking, playing to each standard's strengths.

Posted by Glenn Fleishman at 11:23 AM | Permanent Link | Categories: 802.11n, Bluetooth, Standards|4 Comments

October 13, 2009

Wi-Fi Alliance Peers into the Future with Ad Hoc Replacement

By Glenn Fleishman

Strong peer-to-peer mode added to Wi-Fi portfolio: The Wi-Fi Alliance has announced Wi-Fi Direct, a peer-to-peer wireless networking method that takes the group into a new realm of creating specifications de novo, instead of following IEEE groups. The spec will appear in hardware by mid-2010.

Wi-Fi Direct will allow any device to advertise itself as a combination of software access point and peer. Newer hardware--which will include some existing equipment with firmware upgrades--will be able to maintain a wireless LAN connection to a so-called infrastructure network (via an access point), while also creating a peer-to-peer link to a device like a printer, mouse or keyboard, computer, or handheld. This could be used for file transfers, printing, input, and synchronization, among other purposes.

The spec is backwards compatible with 802.11a and 802.11g, which will see the peering device as a software access point, if I understand that detail correctly.

Wi-Fi Direct will include mechanisms for advertising service availability without connecting, something like the Apple Bonjour method known generically as Zeroconf that uses DNS records to broadcast specific services over a LAN.

The new method is a wholesale replacement of the weak ad hoc networking mode that's part of 802.11, but never built out into a standardized, certified part of Wi-Fi. Ad hoc networks allow devices to exchange data with each other without an access point, but implementations almost universally offer poor security and degraded throughput.

Distinct from ad hoc networks are software access points, which mimic all the functionality of an infrastructure network, and must be operated in a continuous fashion on a computer.

The Wi-Fi Direct mode will not suffer from weaknesses of either type of quasi peer-to-peer methods, and will be rigidly tested for interoperability among devices. Kelly Davis-Felner, the alliance's marketing director, said in an interview that Wi-Fi Direct can preserve the full bandwidth of 802.11n, as well as use WPA2 encryption and WPS (Wi-Fi Protection Setup) secure key handling.

Davis-Felner also said that while the spec has a lot of consumer electronics and home user advantages, enterprise management was baked in as well. The spec requires "Wi-Fi Direct networks to be seen by enterprise APs, and, potentially to be shut down by them" to prevent rogue networks that violate policy, she said. The spec also includes optional mechanisms that allow enterprise access points to suggest channel assignments and power management choices. The spec was designed to be an "enterprise-acceptable solution," Davis-Felner said.

The alliance has pulled together support from many non-standardized PAN/WLAN hybrid modes that have been under development, most notably the Intel My WiFi personal area networking (PAN) extension of 802.11. Intel said via email that Wi-Fi Direct would be incorporated into Intel My WiFi, which has additional capabilities. (My WiFi supports up to eight devices in a PAN configuration, much like Bluetooth.)

Chipmaker Atheros also offers its Direct Connect mode (in addition to a soft access point feature), which it said via email can converge into Wi-Fi Direct. (Oddly, Atheros has no plain product briefing page on this mode.) Marvell has a similar hotspot-on-a-chip offering, and plans Wi-Fi Direct support.

And Ozmo Devices, a chipmaking and integration firm that worked with Intel on its PAN/WLAN technology, is also onboard, deeply involved in writing the spec.

"This has been by far one of the most dynamic and heavily participated in groups that we've had in the Alliance," Davis-Felner said.

Wi-Fi Direct is a bit of a departure for the Wi-Fi Alliance, which typically develops a set of parameters from IEEE standards that a Wi-Fi-compliant device should support, and then builds interoperability testing and certification around those parameters.

With the initial release of Wi-Fi Protected Access (WPA), the Wi-Fi Alliance reacted to the interminable delays at the 802.11i security task group by splitting the backwards-compatible components from all the future-looking elements. WPA was based on an interim 802.11i draft, but ultimately was updated to WPA2 to incorporate the final work of the group.

Here, the alliance isn't following the IEEE, which has no PAN/WLAN convergence group, but maintains separate WLAN (802.11) and PAN (802.15) efforts. The 802.15 group has famously suffered from mid-stream shifts in technology approaches and the disbanding of 802.15.3b (high-speed PAN using UWB).

Wi-Fi Direct could be seen as a challenge to Bluetooth, given that Bluetooth is designed entirely as a PAN, and has a specification that will soon see light that allows Bluetooth to trigger an 802.11-compatible bulk-transfer mode for large files at faster rates. Bluetooth had paired itself with UWB as its next-generation wireless medium, but generic UWB radios never reached market, although there's still some potential.

Posted by Glenn Fleishman at 10:11 AM | Permanent Link | Categories: Bluetooth, Standards|No Comments|No TrackBacks

April 9, 2009

Bluetooth 3.0 Standard Launches This Month

By Glenn Fleishman

The Bluetooth SIG has approved its 3.0 spec with a 21 April launch date: I've written before about Bluetooth 3.0, which pairs the 3 Mbps low-power frequency hopping radio system of 2.1+EDR with high-speed transfers via 802.11 standards. The idea is that a properly integrated Bluetooth 3.0 system will have a bulk-transfer mode that two devices can swap into. (Note that the SIG is referencing 802.11, the generic standard, as it doesn't have a specific program in place with the Wi-Fi Alliance--yet?--for cross-certifiation.)

For instance, if you had one of those ubiquitous BlackBerry or iPhone smartphones with Bluetooth 3.0 and Wi-Fi inside, you could start a sync session with your PC. For normal calendar data and other matter, the sync would use the Bluetooth radio system. To sync a large music or video file, the handset's BT gear would talk with the computer's, agree to switch to 802.11, and then make the bulk transfer. At the end, communication would return to the other radio.

This mode works in a quasi ad-hoc fashion, without requiring that a device join a Wi-Fi network, which is part of why the 802.11 label is being used. With the collapse of UWB as a near-term generic option for personal area networking (PAN)--it may wind up being important, but it's not right now--802.11 standards will likely morph into WLAN/PAN systems. Intel has been working on this for a while, disclosing its Cliffside project a year ago as part of a larger effort to rethink mobile device functions.

Bluetooth 3.0 will get its formal unveiling later this month along with information about which chipmakers have products ready to sample. Because the SIG is a practical group, standards aren't released until there are multiple vendors with interoperable prototype chips and hardware.

Posted by Glenn Fleishman at 10:10 AM | Permanent Link | Categories: Bluetooth

June 2, 2008

Ozmo Aims to Steal Bluetooth's Thunder for Peripherals

By Glenn Fleishman

An Intel-backed startup, Ozmo, plans low-power Wi-Fi protocol modification to compete with Bluetooth technology: Ozmo has developed chips for wireless peripherals like headphones, headsets, and handhelds (the three H's?) as well as mice and keyboards that pair with special driver software for computers to enable a 9 Mbps Wi-Fi-based PAN (personal area network) at the same time a computer is connected via Wi-Fi to a wireless LAN (local area network).

Ozmo apparently is trying to leverage the ubiquity of Wi-Fi, the market reach of Intel (which has invested in the firm and is pushing its technology), and the dissatisfaction with Bluetooth device association and throughput to stick a wedge into Bluetooth's market domination. Well over a billion Bluetooth chipsets have shipped--CSR alone has shipped over a billion--and estimates put half a billion this year into cell phones alone. So there's a large embedded market to overcome.

This new technology, so far unnamed but apparently part of Intel's Cliffside research program, is trying to reduce complexity by reducing the number of standards needed to drive a computer, while increasing the flexibility of those standards. Ozmo and Intel's system would, for instance, allow a simultaneous WLAN connection and a PAN network of up to 8 devices using a single radio on a computer.

The press releases and articles make it quite unclear whether a new Wi-Fi chip would be needed; that chip would almost certainly not conform to today's Wi-Fi standards except in a compatibility mode, given that Wi-Fi has no capacity for PAN-style connections. Ad hoc mode isn't quite the same thing. In the past, extensions to the 802.11 standards that are the basis of the Wi-Fi certification and service mark were allowed as long as basic 802.11 worked as expected.

Bluetooth and Wi-Fi have been complementary technologies for several years. There were early conflicts--I wrote an article about the severe problems in using Bluetooth 1.1 and 802.11b back in 2001! But those interference and coordination issues were resolved, and Blueooth and Wi-Fi marched forward hand in hand, without any close association between the two trade groups behind the standards and branding, but with a lot of technology acquisitions and mergers on the part of companies that make Wi-Fi gear.

The Bluetooth SIG has been working for years to put Bluetooth on top of ultrawideband (UWB), which is still not readily available in the marketplace. UWB is always next year's big technology, and may be passed by except for applications like high-definition video streaming among a/v electronics. The SIG also announced support in Oct. 2007 for Bluetooth + 802.11, where a Bluetooth device could initiate high-speed transfers using 802.11 (yes, Wi-Fi, but not by that name; no partnership there). Bluetooth plus UWB is likely not available until 2009 at this point; BT and Wi-Fi, not until perhaps 2010. (See my article, "Bluetooth to Add Wi-Fi with UWB Delays in Mind," 2007-10-31.)

It's hard to see how Ozmo builds a place in this infrastructure, even with higher bandwidth, and what Ozmo says is lower power use and a lower cost for their chips, because laptop and desktop makers will need to buy into the Intel/Ozmo ecosystem. The demand for this kind of technology is typically driven by users who buy one component and need their computer to interface with it.

With Ozmo and Intel apparently planning to debut the Wi-Fi chips and driver support next year, it seems like a multi-year process to figure out whether Ozmo can evolve a competitive position to Bluetooth, even as Bluetooth is estimated to be embedded in over 1.2b cell phones by 2012.

Posted by Glenn Fleishman at 11:04 AM | Permanent Link | Categories: Bluetooth, Future

February 10, 2008

Bluetooth Will Add 802.11 for Bulk Data Transfer

By Glenn Fleishman

The Bluetooth SIG says a 2009 standard will integrate Bluetooth and 802.11 in a tighter, more complementary relationship: The group that controls the Bluetooth standard continues the evolution towards agnosticism about underlying radio stuff. The latest move takes advantage of the side-by-side deployment of the "winning" wireless specifications: Bluetooth for PAN (Personal Area Networks) and Wi-Fi for WLAN (Wireless Local Area Networks). Bigger files will automatically be sent over Wi-Fi. Sounds simple, no?

"Bluetooth is great right now for sending some of these less bulky data files," said senior marketing manager Kevin Keating, but with the "bulk transfer of entertainment data, whether it's piles of MP3s or a bunch of vacation photos you want to move off your cameras or on your PC, it's not really built for that."

The SIG made this announcement this afternoon at the Mobile World Conference in Barcelona; Bluetooth is built into hundreds of millions of cell phones worldwide in its current form, and is near two billion devices shipped in all form factors. That number went from 1 to 2 billion in about two years.

The new standard, called Bluetooth High Speed, will allow a Bluetooth adapter and drivers to identify bulk transfers and move them from the lower-powered and slower Bluetooth radio technology to more battery intensive, but faster 802.11.

They're really talking about 802.11 and Wi-Fi nearly interchangably, but this standard doesn't yet have any formal involvement from the SIG's counterpart, the Wi-Fi Alliance, which controls the certification process for Wi-Fi and the trademark. Keating said, "Wi-Fi is its own brand, and we've talked."

It's important to remember that Bluetooth is both a set of profiles that define behavior--applications and schemas for data in those applications--and a radio standard. Bluetooth was originally developed with its own communications spec (the MAC and PHY, in technical terms) that worked at 1 Mbps; the 2.0+EDR and 2.1+EDR (Enhanced Data Rate) bumped that to 3 Mbps. (Version 2.1 also dramatically simplifies pairing between devices; it's rolling out widely now.)

These profiles include things like HID (Human Interface Device) for keyboards and input devices, DNP for dial-up networking, GOEP (Generic Object Exchange Profile) for file transfer, and so forth. The profiles are at a layer of abstraction above the interface and radio part, which makes it relatively simple to repurpose them across many radio standards.

In that vein, the Bluetooth SIG has already disclosed plans for its support for ultrawideband (UWB), whenever PCs with UWB or adapters start appearing in great provision, and their own ultra low power version of Bluetooth for things like heart-rate monitor, bike cyclometers sensors, and other low-data-rate devices.

The Bluetooth SIG says prototypes using the high-speed standard will be tested this year, with a published spec due in mid-2009, and devices presumably long before the end of 2009.

Posted by Glenn Fleishman at 9:00 AM | Permanent Link | Categories: Bluetooth, Future, Standards

October 31, 2007

Bluetooth to Add Wi-Fi with UWB Delays in Mind

By Glenn Fleishman

The Bluetooth SIG will create a version that runs over Wi-Fi: Bluetooth comprises applications and radio standards. The applications include standard profiles that developers use to add features like keyboard and input device access, file transfer, and dial-up networking. The Bluetooth SIG has a long-range plan to keep Bluetooth relevant by essentially adding more radio technologies underneath, not just the 1 Mbps version found in Bluetooth 1.x and the 3 Mbps version in the Enhanced Data Rate (EDR) part of 2.x+EDR.

Ultrawideband (UWB) was one of the preferred newer radio standards, something they decided on supporting in March 2006, because UWB seemed to be near term at that point, and was part of the original migration path for personal area networking in the IEEE 802.16 group that Bluetooth has some coordination with. (UWB was to be the radio standard for 802.16.3a until the group disbanded over friction caused by a now-dropped original flavor of UWB from what is now Motorola spin-off Freescale.) UWB is low-power and low-range, making it ideal.

But it's hardly on the market yet and is way too expensive. This pushes back Bluetooth over UWB in handsets to something like 2009. TechWorld notes that UWB vendors say that UWB handsets will be on the market (in Asia) within six months. Of course, UWB chipmakers and manufacturers have been telling me since 2006 that UWB products will be shipping in a few months. They weren't lying; complications ensued. I accept that. But I'm now Missouri as regards UWB in shipping hardware.

As a result, TechWorld reports, the SIG's chair, ironically a Motorola employee, said that they would focus on building Bluetooth over Wi-Fi. Details aren't available, and one UWB vendor says that Wi-Fi and Bluetooth are incompatible due to security models.

Posted by Glenn Fleishman at 4:00 PM | Permanent Link | Categories: Bluetooth, Hardware, UWB

August 1, 2007

Bluetooth Group Adopts Better Pairing, Lower Power Rules

By Glenn Fleishman

The Bluetooth SIG's board of directors approved 2.1+EDR (Enhanced Data Rate): The revision of the short-range personal area networking standard will reduce power consumption and greatly ease pairing, the association between two Bluetooth devices. The changes can be applied to 2.0+EDR devices via firmware, the Bluetooth SIG told me, but many Bluetooth modules are now in devices that lack firmware upgrade ability. So computers, yes; phones, many; picture frames, perhaps not so much.

Pairing has been dramatically improved by reducing the number of steps and the complexity. For devices that require a passcode entry, version 2.1+EDR requires that one device in the paired set generates a six-digit PIN that is then entered in the other device. And you're done. (Apple created their own version of this years ago, but it worked only when devices were discoverable and paired by Mac OS X to a computer, and it was far less secure than the 2.1+EDR version.)

The PIN is generated, by the way, using an Elliptic Curve Diffie-Hellman algorithm, which avoids man-in-the-middle (MitM) attacks by using an out-of-band method to confirm a key exchange. In this case, the two Bluetooth 2.1+EDR devices generate and exchange their ECDH keys, and then one device generates a six-digit PIN which is part of a hash of the session key being used by the two devices. While an MitM can talk to both parties, they can't know that six-digit PIN.

The improvement in power usage is rather significant: the SIG reports a fivefold improvement in battery life by intermittently connected devices like sensors, and input devices that send very little actual information, like keyboards and mouses.

Posted by Glenn Fleishman at 4:34 PM | Permanent Link | Categories: Bluetooth, Standards|1 Comment

June 12, 2007

Bluetooth Extends Usefulness with Wibree Inclusion

By Glenn Fleishman

The Bluetooth SIG will incorporate Nokia's wearable Wibree technology into its portfolio: Nokia sparked some interest when it unveiled Wibree last year because of the niche it filled: wireless technology with miserly power use that could fit in a tiny form factor, like wearable items. But there were also groans. With Bluetooth, ultrawideband, Wi-Fi, WiMax, and ZigBee already extant--not another technology standard, please!

Fortunately, Nokia is contributing Wibree to the Bluetooth SIG, and the Wibree Forum (which includes Broadcom and other firms) will become part of the fold, too. Contributing is the operative word: Nokia will allow the use of Wibree royalty free. Bluetooth itself was turned into a royalty-free offering to push its adoption.

Wibree-based products will be marketed as ultra-low-power Bluetooth, and have a goal of a year's battery life, 10-meter range, and 1 Mbps throughput. Current Bluetooth products have no battery-life target that I'm aware of, and can operate at ranges of 10 meters (Class 2) or 100 meters (Class 1), and up to 3 Mbps with Bluetooth 2.0+HDR (high data rate). Existing Bluetooth devices won't talk to Wibree equipment, but future Bluetooth standards can incorporate that ability, as Wibree uses 2.4 GHz frequency hopping radios.

This might seem to put the Bluetooth SIG in competition with the ZigBee Alliance, which products products that use the IEEE 802.15.4 standard for low-power, long-battery-life, short-range, low-speed wireless communication. (By the way, IEEE 802.15.1 is a subset of Bluetooth.) ZigBee, however, is focused on devices in the home and office like alarm and fire sensors, A/V equipment (like a TV remote control), and "white" appliances like refrigerators that might have something to say to its owner. Wibree's intent is centered around small, mobile devices where Bluetooth might be too bulky or power-intensive. We'll see if worlds collide.

Part of the Bluetooth SIG's real genius in recent years--and, yes, its director Mike Foley deserves to be credited--is embrace, adopt, extend. Bluetooth was clearly on a path to obsolescence with its specific radio technology, even as developers and hardware manufacturers continued to cram Bluetooth into everything mobile. It didn't have a good roadmap with a single offering with incremental improvements--like moving from 1 Mbps to 3 Mbps.

What's critical to know about Bluetooth is that it's a pile of specific application-layer tasks (which they call "profiles") combined with underlying radio technology. The radio technology is, frankly, irrelevant except insofar as the original and current Bluetooth standards codified a common way of exchanging low-speed data wirelessly. That's great, but there are a lot of methods, and there's nothing particularly special or important about Bluetooth's RF.

Rather, the value is in the profiles, like file transfer, printing, hands-free access, and dial-up networking. These profiles are abstracted from the radio, which means that programmers never have to think about the RF properties of the device in order to use profiles. (They might think about efficiency for bandwidth and battery usage, but not about radio-wave propagation.)

This has allowed the Bluetooth SIG to embrace ultrawideband (UWB) and Wibree without compromising its existing set of products or alienating developers. In fact, it's a boon to all electronics makers: a handset or smartphone maker could add or switch to UWB from the Bluetooth RF standard without losing Bluetooth's capabilities. (UWB is always next year's technology. Late last year, it looked like 2007 was going to be the year. But we're still waiting for the first real UWB products to hit the marketplace.)

Posted by Glenn Fleishman at 12:16 PM | Permanent Link | Categories: Bluetooth, Standards, ZigBee

March 27, 2007

Bluetooth 2.1: Simpler, Longer Lived

By Glenn Fleishman

The Bluetooth SIG unveiled its 2.1 spec today: Ephraim Schwartz of InfoWorld gave a preview 10 days ago, and the wraps were taken off at the cell industry trade show CTIA today. Bluetooth 2.1 makes pairing two devices a snap. Power usage has been taken down several notches, too, allowing five times the battery life for devices that don't send continuous data, such as mice, keyboards, watches, sensors, and "medical devices," the SIG says.

As a 2.1 spec, one hopes that some devices will upgradable to support new pairing. There was no announcement as to whether manufacturers were planning upgrades. Conceivably, most of the changes are at the application layer, and existing silicon could support the process using existing circuits, or by offloading elements to the operating system driver. The lower-power mode sounds like a protocol change that could be handled in a firmware upgrade, except that the devices likely to benefit from it also are likely to have no rewritable memory nor an interface by which to update their firmware.

I haven't seen a demonstration yet, but I'm familiar with the methods by which Bluetooth pairing has been simplified. In the past, pairing two devices meant navigating down several menus or depressing buttons, and then inventing a code on one device and entering it on the other, or finding the code that was embedded in the device by default. It could take as many as 14 steps with some sets of devices to pair them.

The new method is much simpler. You'll push a button on a headless Bluetooth device, and then choose Add Bluetooth Device or a similar simple item from a top-level entry on a phone, computer, or handheld. You're done. If you need security, such as pairing two computers, you'll push one computer into pairing mode, and enter a code that computer generates into an interface on the other machine. And you're done.

And you beat the man-in-the-middle attack. The new system creates a strong passkey, so you don't have to invent a PIN, and the out-of-band display of the passkey on the initiating device allows confirmation of the integrity of the encrypted connection. (Apple had its own version of this with a PIN: when pairing, Mac OS X generates a random PIN you enter in the paired device.)

It's so simple, you wish that they had developed this, say, four years ago. But times change, and ideas evolve. Nobody invented Bluetooth pairing to make life hard. And engineers don't think that 14 well-documented steps are a bar to use.

The new Bluetooth 2.1 methods are rather similar to a couple of modes in Wi-Fi Protected Setup (WPS), with some differences in implementation, but the same ease of use. (I've tested WPS with the new 802.11n AirPort Extreme Base Station and a properly equipped Mac with an N adapter. Lovely, simple, fast--and very secure.)

Bluetooth 2.1 also supports near-field communication (NFC) as an option, where you hold two devices close to each other when engaged in the pairing process. NFC isn't available on a widespread basis yet, but there's a lot of interest in it.

Posted by Glenn Fleishman at 2:20 PM | Permanent Link | Categories: Bluetooth

March 16, 2007

Simpler Bluetooth Due in Late 2007

By Glenn Fleishman

Good news from the simplicity front: The Bluetooth SIG told InfoWorld's Ephraim Schwartz that the 2.1 update to the standard that would appear later this year would automate parts of the pairing process to reduce hooking up two devices down to perhaps 2 to 3 steps.

In writing about Bluetooth, I've always been stunned by how many steps are necessary to create a connection, even in ideal circumstances. The Wi-Fi Alliance learned from this, and their Wi-Fi Protected Setup--a kind of pairing for simple WPA security--involves as few as two steps on a base station and one on a computer trying to associate to form an encrypted pairing.

The new 2.1+EDR spec also uses as little as 20 percent as much power through better sleep modes. Schwartz writes the spec should ship to device manufacturers in two months, but I wonder if he means that chipmakers will have implemented versions that can be integrated in devices in two months?

Posted by Glenn Fleishman at 10:09 AM | Permanent Link | Categories: Bluetooth|1 Comment

January 16, 2007

CSR Combines Bluetooth, GPS in Single Chip

By Glenn Fleishman

The chipmaker CSR wants to preserve existing Bluetooth business by offering GPS as a cheap, incremental improvement: CSR says that it will cost about $1 to add a GPS receiver in a combined Bluetooth/GPS chip, and that the chip--make possible by its acquisition of two GPS firms--will have far higher sensitivity than other chips on the market. E911 service in the US requires some kind of automated location service be embedded in phones. As location services are now being sold by carriers based on their cheap, embedded GPS receivers, CSR may have a market in providing better positioning, a lower bill-of-goods, and better battery life.

Posted by Glenn Fleishman at 8:24 PM | Permanent Link | Categories: Bluetooth, Location

January 3, 2007

Bluetooth Has Patent Woes

By Glenn Fleishman

First Wi-Fi, now Bluetooth: On the heels of Australian technology agency CSIRO winning a key patent suit against Buffalo Technology over the use of very specific elements of newer Wi-Fi standards, the University of Washington's patent-licensing arm has sued four electronics makers that incorporate Bluetooth chips made by CSR into their products: Nokia, Samsung, and both Matsushita and its subsidiary Panasonic of North America. The Washington Research Foundation has patents created by an undergraduate and assigned to the school that the WRF claims are infringed by CSR chips. WRF has a licensing agreement in place with CSR's competitor, Broadcom.

CSR stated today that the claims are without merit. One article says that WRF sued customers because CSR sells chips worldwide, but the customers deliver products specific to the US market that incorporate CSR chips.

The patents were apparently developed in the mid-1990s, according to The Seattle Times, but one of the patents in dispute was not filed until 2003; it was granted in Oct. 2006. The Bluetooth SIG's members agreed to cross-license technology, but WRF is outside that process.

Posted by Glenn Fleishman at 9:02 PM | Permanent Link | Categories: Bluetooth, Legal

December 3, 2006

Qualcomm Buys Airgo

By Glenn Fleishman

The cell-phone tech giant buys early MIMO company: Airgo was a pioneer in commercializing multiple-antenna (multiple-in/multiple-out or MIMO) technology for the mass market. While one might quibble with some of the particulars of their marketing or their confidence in their precise technology decisions, there's no question that they were the first to market with Wi-Fi plus MIMO, that they helped set the direction of the industry towards MIMO, and that they continue to be a significant player--although that significance was in danger of being challenged by the success of MIMO as a component in wireless data networking.

Their acquisition by Qualcomm ensures their future relevance. Qualcomm says they'll continue to support Airgo's lines of business, but will also integrate their Wi-Fi technology into the Mobile Station Modem chipsets and Snapdragon platform, both of which are designed to give Qualcomm a full place at the converged "table," in which cellular data is one of multiple options for connectivity.

MIMO makes it possible to carry more data over the same frequencies through reuse of those frequencies across space (spatial multiplexing), while also increasing receive sensitivity and transmission clarity, resulting in greater effective area covered by a transceiver.

A related announcement made my head spin. Airgo is claiming the availability of 802.11n Draft 2.0 chipsets that are fully backward compatibility with Draft 1.0 features, and 802.11a/b/g. Now this is hard to swallow given that Draft 2.0 won't be actually voted on until March 2007. In fact, the latest notes from the November meeting of Task Group N--the group responsible for the drafts--explains that 370 technical comments are left to address (88 percent have been gone through) with expected approval on the resolution of those comments by the January meeting. Only by that happening would a ballot be created that could then be approved for the March 2007.

So I have to ask--what kind of crack is Airgo/Qualcomm smoking, and how do I get me some? I'd love to be able to exist simultaneously four months in the future and today; it would make investing much easier. This announcement from a company that denounced Draft 1.0 chip releases is especially rich.

I expect we will get all kinds of qualifications from Qualcomm, and all kinds of denunciations from competing chipmakers. What they will certainly claim is something like, "Based on our expectations of how the final 370 comments will be addressed, we currently comply with the state of Draft 2.0 in progress." That is, they will claim compliance with a DRAFT OF A DRAFT and state that with a straight face. This is why I am not in marketing.

Update on 2.0: In email with an Airgo spokesperson, the company stated that the chips will include all possible iterations of ideas still under discussion and incorporate everything that could possibly be in 2.0. This is probably true. But there's a great difference between "we anticipate Draft 2.0" and "we're Draft 2.0 compliant," which is logically and linguistically impossible. Airgo's CEO--newly minted VP of wireless connectivity at Qualcomm--Greg Raleigh told Wi-Fi Planet: " 'We've had a year of debate and negotiation in the IEEE,' says Raleigh. In that time, lots of features have been introduced as possibilities for 802.11n and Airgo plans to support just about everything that’s come up. In fact, he says Airgo argued to include most of them while some other vendors argued to have features taken out."

It's still specious to call their new chips Draft 2.0 compliant.

Another update: TechWorld talked to someone at Qualcomm who said that "availability" doesn't mean that chips are available. "With no possibility of a Draft 2.0 design until after then, Qualcomm vice president Enrico Salvatori admitted to us that the Draft 2.0 silicon was not actually "available" was planned for sample quantities in the second half of 2007."

Airgo, by the way, has a pile of patents, and while I haven't heard boo so far about them attempting to enforce these in any fashion--and as a participant in IEEE, they've had to agree to certain licensing terms--I expect Qualcomm to follow its usual aggressive strategy. Which means bloody noses, lawsuits, and so on. Qualcomm is in the midst of being sued by and suing a variety of competitors, involving patents that parties claim other parties have used without permission and the cost of patent royalties.

Qualcomm announced another purchase today, too. The deal is described as Qualcomm acquiring the "majority of RF Micro Devices' Bluetooth assets," which is a little difficult to parse, but ostensibly means patents, processes, licenses, and inventories.

Posted by Glenn Fleishman at 10:31 PM | Permanent Link | Categories: 802.11n, Bluetooth, Financial

November 15, 2006

Bluetooth Tops One Billion

By Glenn Fleishman

For a failed technology, it's looking pretty good: Weekly unit shipments are 12m in devices; in 2010, they have a goal of shipping two billion units--in that year. Bluetooth 2.0+EDR solved a lot of frustration with throughput, range, and co-existance, making a better audio experience possible. The future of Bluetooth is now tied to UWB, and it's a year until we'll see the fruits of that collaboration. With Bluetooth over UWB, the same applications will be available with little effort on the part of developers to make them work with a different radio set.

Posted by Glenn Fleishman at 2:55 PM | Permanent Link | Categories: Bluetooth

October 18, 2006

Retro Bluetooth Handset from ThinkGeek

By Glenn Fleishman

I love the smell of Bakelite in the morning: The fine people at ThinkGeek have taken their USB-corded retro handset  and cut the cord. This Bluetooth handset has the charm of the old AT&T telephones, with the flexibility of Bluetooth. For $40, it's an easy sell for the stylish and those that like that full-sized effect. (They continue to sell their USB-only version for $30; this Bluetooth version includes a USB connector for charging.) [link via Gizmodo]

Posted by Glenn Fleishman at 11:21 AM | Permanent Link | Categories: Bluetooth, Unique|1 Comment

October 12, 2006

Bluetooth Will Push From Web Page to Portable Device

By Glenn Fleishman

The Bluetooth SIG announces a kind of Web clipping service: The new TransSend feature will let you click an icon next to a chunk of information on a Web page--like an address, map, contact, or arbitrary text--and have that pushed to any Bluetooth device in range. There's no retrofit needed for the Bluetooth phone or mobile device, as the transfers use an existing Bluetooth profile and formats. But you will need to install software on the computer; only Windows XP SP2 and Windows 2000 are supported at first, and only with IE 5.5 or later. Other platforms and browsers are "under consideration."

The software allows any arbitrary selection to be clipped by using a right-click menu that appears in the browser after selection. However, Web developers can update their pages with appropriate tags to identify TransSend regions, which will be a cinch for directories, mapping companies, and other services that specialize in this sort of information.

Posted by Glenn Fleishman at 4:22 PM | Permanent Link | Categories: Bluetooth

April 21, 2006

Ultrawideband Has Ultrawide Differences of Opinion

By Glenn Fleishman

Peter Judge writes a UWB Soap three-parter: It's daytime theater on the air as Judge presents the views of Freescale, the Bluetooth SIG, and the WiMedia Alliance on the future of UWB and Bluetooth. You'll laugh, you'll cry, you'll consult stock market reports.

Part one covers the views of Martin Rofheart, a pioneer of UWB and head of Freescale's wireless efforts, but whose particular flavor appears marginalized and sidelined to my eyes. Freescale's UWB technology was dropped by Bluetooth and Freescale and former parent Motorola left the trade group they helped form. While promising shipping silicon for years, Freescale now seems poised to deliver it at last this July--but only running at 110 Mbps, not the promised 480 Mbps speed sought for the last couple of years. Rofheart makes a lot of claims for how his competition's version of UWB is further behind and less capable. Freescale plans to deliver Cable Free USB, which will work seamlessly through dongles and hubs with existing USB 2.0 connections and devices.

Part two looks into whether Bluetooth has a future given recent developments. Judge notes that Freescale's Rofheart believes Bluetooth over UWB will be late to market and have a restricted worldwide appeal due to choices about spectrum. Will no-wire USB simply take the day? Hard to say, although there's a lot of good technical detail here to absorb. Fundamentally, Bluetooth is about applications running over a radio, while USB is about connectivity. For companies already invested in Bluetooth, adding UWB as a radio option should involve less effort than retooling around USB. Although USB is commonly used for phone synchronization, too. It should prove entertaining.

Part three has the WiMedia Alliance chiming in with their upcoming delivery dates and refuting much of what Rofheart says. (There's no rebuttal from Freescale yet, but part three just posted.) The WiMedia Alliance says that Certified Wireless USB will provide better throughput than Freescale's Cable Free USB by a long shot, and that a single radio for future application and connectivity standards for short-range networks  is the right way to go.

The soap opera won't reach its conclusion until products ship. Stay tuned.

Posted by Glenn Fleishman at 4:58 PM | Permanent Link | Categories: Bluetooth, Future, UWB

March 30, 2006

If This Bluetooth Is Rocking, Don't Come-a Call Waitin'

By Glenn Fleishman

Texas Instruments introduces a Bluetooth chip that rocks, dude! Its BlueLink 6.0 platform couples FM radio reception (mono and stereo) with Bluetooth in a single chip. This module also co-exists neatly with Wi-Fi. The notion is that a handset could be an FM tuner without additional chips or integration; this feature must be a top request as music players are added into phones. One analyst predicts 400m units with FM reception by the end of the decade.

Of course, if I put on my other hat, I know that HD Radio, a digitally encoded form of AM and FM radio, has begun making headway in the market. HD Radio uses unused guard bands around the primary analog frequencies to deliver crisp, even multi-channel audio. It makes a lot of sense in about two years to have HD Radio-only AM and FM tuners in handsets. About 700 stations broadcast HD Radio today and only a few car receivers, one high-end home receiver, and one tabletop radio can tune in these broadcasts. A few thousand stations will have added HD by 2007.

The platform works with all common cell phone standards (2G through 3G), as well as Linux, Microsoft, and Symbian operating systems. The chips in two modules are in sampling with devices expected in early 2007 based on the technology.

Posted by Glenn Fleishman at 9:56 AM | Permanent Link | Categories: Bluetooth, Chips, Unique

March 28, 2006

Bluetooth SIG Adopts WiMedia's UWB Flavor

By Glenn Fleishman

The group that controls Bluetooth's evolution decided to favor the WiMedia Alliance's flavor of ultrawideband (UWB): UWB offers speeds of 110 Mbps to 480 Mbps over distances of 10 down to 1 meters in its current incarnation. Two incompatible versions are backed by separate alliances. The WiMedia Alliance includes Intel and a number of other semiconductor makers, computer technology manufacturers, and consumer electronics firms. The other alliance--UWB Forum--is Freescale with just a few significant companies in the mix, including former parent Motorola.

The Bluetooth SIG had earlier signaled that it would support development of Bluetooth profiles and technology--such as object exchange (file transfer) and other widely supported and implemented higher-level modules for action--on top of the classic UWB that Freescale will release shortly to its manufacturing partners and the MB-OFDM flavor developed by WiMedia. (Freescale has talked about production silicon for years, but still lacks a single product on the market; July is the target for two partners for a USB 2.0 hub that uses UWB.)

Now, WiMedia is the only dance partner for the Bluetooth SIG. In an article in ExtremeTech, the SIG's head, Mike Foley says that the trade group's members heavily favored the WiMedia version of UWB. Freescale's head Martin Rofheart said in the same article that the company's short-term focus reamins USB 2.0 replacement given that Bluetooth-based high-speed applications won't be ready until some time in 2007 in the revised scheduled announced today.

A year ago, Rofheart said:

Fast Bluetooth may beat Wireless USB to the market, said Rofheart, since the high-level protocols are in place, and Freescale's silicon is further ahead: "The pieces are more mature, and can be wed together more quickly, rolling into the market faster."

This has proven not to be true. A demonstration last October showed Bluetooth operating over the Freescale flavor of UWB. Freescale and a few other firms that back its flavor are members of the Bluetooth SIG. Motorola was an original promoter and founder of the SIG. Freescale and Motorola have enormous product portfolios, however, and this Bluetooth SIG decision might not cause either company to leave the trade group.

The Bluetooth SIG is pursuing several different paths to make its applications continue to be relevant given the slow speed of its current paired radio technology--just 3 Mbps with Bluetooth 2.0+SDR. The applications allow for wide interoperability and leverage legions of developers who have written Bluetooth support. Changing the radio out from underneath Bluetooth is relatively straightforward compared with the adoption of an entirely new specification from top to bottom, which is why Bluetooth appears to have legs as it follows UWB, Near Field Communications (a form of very close proximity communication), and even Wi-Fi.

ABI Research

Источник: [https://torrent-igruha.org/3551-portal.html]
, Bluetooth technology Archives

Archived Specifications

CoreCS – Core Specification5.1LegacyCS v5.2CoreCS – Core Specification5LegacyCS v5.2CoreCS – Core Specification4.2LegacyCS v5.2CoreCS – Core Specification4.1Deprecated, to be withdrawn28/01/201901/02/2023CS v5.2CoreCS – Core Specification4.0Deprecated, to be withdrawn28/01/201901/02/2022CS v5.2CoreCS – Core Specification3.0+HSWithdrawn28/01/201901/07/2020CS v5.2CoreCS – Core Specification2.1+EDRWithdrawn28/01/201901/07/2020CS v5.2CoreCS – Core Specification2.0+EDRWithdrawn28/01/2019CS v5.2CoreCS – Core Specification1.2Withdrawn27/01/2009CS v5.2CoreCS – Core Specification1.1Withdrawn09/02/2006CS v5.2CoreCS – Core Specification1.0BWithdrawn17/01/2006CS v5.2CoreCSA – Core Specification Addendum6LegacyCS v5.2CoreCSA – Core Specification Addendum5LegacyCS v5.2CoreCSA – Core Specification Addendum4Deprecated, to be withdrawn28/01/201901/02/2022CS v5.2CoreCSA – Core Specification Addendum3r2Deprecated, to be withdrawn28/01/201901/02/2022CS v5.2CoreCSA – Core Specification Addendum2Deprecated, to be withdrawn28/01/201901/02/2022CS v5.2CoreCSA – Core Specification Addendum1Withdrawn28/01/201901/07/2020CS v5.2CoreCSS – ​Core Specification Supplement8Withdrawn31/12/2019Active CSSCoreCSS – ​Core Specification Supplement7Withdrawn28/01/2019Active CSSCoreCSS – ​Core Specification Supplement6Withdrawn06/12/2016Active CSSCoreCSS – ​Core Specification Supplement5Withdrawn14/07/2015Active CSSCoreCSS – ​Core Specification Supplement4Withdrawn02/12/2014Active CSSCoreCSS – ​Core Specification Supplement3Withdrawn03/12/2013Active CSSCoreCSS – ​Core Specification Supplement2Withdrawn12/02/2013Active CSSCoreCSS – ​Core Specification Supplement1Withdrawn12/02/2013Active CSSGATTBLP – Blood Pressure Profile1.0LegacyBLP v1.0.1GATTCGMP – Continuous Glucose Monitoring Profile1.0To be deprecated01/02/202101/02/2022CGMP v1.0.1GATTCGMS – Continuous Glucose Monitoring Service1.0To be deprecated01/02/202101/02/2022CGMS v1.0.1GATTCPP – Cycling Power Profile
Источник: [https://torrent-igruha.org/3551-portal.html]
Bluetooth technology Archives

Bluetooth

Short distance wireless technology standard

Bluetooth is a wireless technology standard used for exchanging data between fixed and mobile devices over short distances using UHFradio waves in the industrial, scientific and medical radio bands, from 2.402 GHz to 2.480 GHz, and building personal area networks (PANs). It was originally conceived as a wireless alternative to RS-232 data cables.

Bluetooth is managed by the Bluetooth Special Interest Group (SIG), which has more than 35,000 member companies in the areas of telecommunication, computing, networking, and consumer electronics. The IEEE standardized Bluetooth as IEEE 802.15.1, but no longer maintains the standard. The Bluetooth SIG oversees development of the specification, manages the qualification program, and protects the trademarks.[3] A manufacturer must meet Bluetooth SIG standards to market it as a Bluetooth device.[4] A network of patents apply to the technology, which are licensed to individual qualifying devices. As of 2009[update], Bluetooth integrated circuit chips ship approximately 920 million units annually.[5]

History[edit]

The development of the "short-link" radio technology, later named Bluetooth, was initiated in 1989 by Nils Rydbeck, CTO at Ericsson Mobile in Lund, Sweden. The purpose was to develop wireless headsets, according to two inventions by Johan Ullman, SE 8902098-6, issued 1989-06-12  and SE 9202239, issued 1992-07-24 . Nils Rydbeck tasked Tord Wingren with specifying and Dutchman Jaap Haartsen and Sven Mattisson with developing. Both were working for Ericsson in Lund.[6] In 1990, Jaap Haartsen was nominated by the European Patent Office for the European Inventor Award. [7] From 1997 Örjan Johansson became the project leader and propelled the technology and standardization.[8][9][10][11]

In 1997, Adalio Sanchez, then head of IBM ThinkPad product R&D, approached Nils Rydbeck about collaborating on integrating a mobile phone into a ThinkPad notebook. The two assigned engineers from Ericsson and IBM to study the idea. The conclusion was that power consumption on cellphone technology at that time was too high to allow viable integration into a notebook and still achieve adequate battery life. Instead, the two companies agreed to integrate Ericsson's short-link technology on both a ThinkPad notebook and an Ericsson phone to accomplish the goal. Since neither IBM ThinkPad notebooks nor Ericsson phones were the market share leaders in their respective markets at that time, Adalio Sanchez and Nils Rydbeck agreed to make the short-link technology an open industry standard to permit each player maximum market access. Ericsson contributed the short-link radio technology, and IBM contributed patents around the logical layer. Adalio Sanchez of IBM then recruited Stephen Nachtsheim of Intel to join and then Intel also recruited Toshiba and Nokia. In May 1998, the Bluetooth SIG was launched with IBM and Ericsson as the founding signatories and a total of five members: Ericsson, Intel, Nokia, Toshiba and IBM.

The first consumer Bluetooth device was launched in 1999. It was a hands-free mobile headset which earned the "Best of show Technology Award" at COMDEX. The first Bluetooth mobile phone was the Ericsson T36 but it was the revised T39 model which actually made it to store shelves in 2001. In parallel, IBM introduced the IBM ThinkPad A30 in October 2001 which was the first notebook with integrated Bluetooth.

Name and logo[edit]

Name[edit]

The name Bluetooth is an Anglicised version of the Scandinavian Blåtand/Blåtann (Old Norseblátǫnn), the epithet of the tenth-century king Harald Bluetooth who united dissonant Danish tribes into a single kingdom. The implication is that Bluetooth unites communication protocols.[12]

The idea for this name was proposed in 1997 by Jim Kardach of Intel, who developed a system that would allow mobile phones to communicate with computers.[13] At the time of this proposal he was reading Frans G. Bengtsson's historical novel The Long Ships about Vikings and King Harald Bluetooth.[14][15]

Logo[edit]

The Bluetooth logo is a bind rune merging the Younger Futharkrunes (ᚼ, Hagall) and  (ᛒ, Bjarkan), Harald's initials.[16][17]

Implementation[edit]

Bluetooth operates at frequencies between 2.402 and 2.480 GHz, or 2.400 and 2.4835 GHz including guard bands 2 MHz wide at the bottom end and 3.5 MHz wide at the top.[18] This is in the globally unlicensed (but not unregulated) industrial, scientific and medical (ISM) 2.4 GHz short-range radio frequency band. Bluetooth uses a radio technology called frequency-hopping spread spectrum. Bluetooth divides transmitted data into packets, and transmits each packet on one of 79 designated Bluetooth channels. Each channel has a bandwidth of 1 MHz. It usually performs 1600 hops per second, with adaptive frequency-hopping (AFH) enabled.[18]Bluetooth Low Energy uses 2 MHz spacing, which accommodates 40 channels.[19]

Originally, Gaussian frequency-shift keying (GFSK) modulation was the only modulation scheme available. Since the introduction of Bluetooth 2.0+EDR, π/4-DQPSK (differential quadrature phase-shift keying) and 8-DPSK modulation may also be used between compatible devices. Devices functioning with GFSK are said to be operating in basic rate (BR) mode where an instantaneous bit rate of 1 Mbit/s is possible. The term Enhanced Data Rate (EDR) is used to describe π/4-DPSK and 8-DPSK schemes, each giving 2 and 3 Mbit/s respectively. The combination of these (BR and EDR) modes in Bluetooth radio technology is classified as a BR/EDR radio.

In 2019, Apple published an extension [1] called HDR which supports data rates up to 8Mbit/s.

Bluetooth is a packet-based protocol with a master/slave architecture. One master may communicate with up to seven slaves in a piconet. All devices within a given piconet use the clock provided by the master as the base for packet exchange. The master clock ticks with a period of 312.5 μs, two clock ticks then make up a slot of 625 µs, and two slots make up a slot pair of 1250 µs. In the simple case of single-slot packets, the master transmits in even slots and receives in odd slots. The slave, conversely, receives in even slots and transmits in odd slots. Packets may be 1, 3 or 5 slots long, but in all cases the master's transmission begins in even slots and the slave's in odd slots.

The above excludes Bluetooth Low Energy, introduced in the 4.0 specification, which uses the same spectrum but somewhat differently.

Communication and connection[edit]

A master BR/EDR Bluetooth device can communicate with a maximum of seven devices in a piconet (an ad-hoc computer network using Bluetooth technology), though not all devices reach this maximum. The devices can switch roles, by agreement, and the slave can become the master (for example, a headset initiating a connection to a phone necessarily begins as master—as an initiator of the connection—but may subsequently operate as the slave).

The Bluetooth Core Specification provides for the connection of two or more piconets to form a scatternet, in which certain devices simultaneously play the master role in one piconet and the slave role in another.

At any given time, data can be transferred between the master and one other device (except for the little-used broadcast mode). The master chooses which slave device to address; typically, it switches rapidly from one device to another in a round-robin fashion. Since it is the master that chooses which slave to address, whereas a slave is (in theory) supposed to listen in each receive slot, being a master is a lighter burden than being a slave. Being a master of seven slaves is possible; being a slave of more than one master is possible. The specification is vague as to required behavior in scatternets.[20]

Uses[edit]

Class Max. permitted power Typ. range[2]
(m)
(mW) (dBm)
1 10020~100
1.5
(BT 5 Vol 6 Part A Sect 3)
1010~20
2 2.54~10
3 10~1
4 0.5−3~0.5

Bluetooth is a standard wire-replacement communications protocol primarily designed for low power consumption, with a short range based on low-cost transceivermicrochips in each device.[21] Because the devices use a radio (broadcast) communications system, they do not have to be in visual line of sight of each other; however, a quasi optical wireless path must be viable.[22] Range is power-class-dependent, but effective ranges vary in practice. See the table "Ranges of Bluetooth devices by class".

Officially Class 3 radios have a range of up to 1 metre (3 ft), Class 2, most commonly found in mobile devices, 10 metres (33 ft), and Class 1, primarily for industrial use cases,100 metres (300 ft).[2] Bluetooth Marketing qualifies that Class 1 range is in most cases 20–30 metres (66–98 ft), and Class 2 range 5–10 metres (16–33 ft).[1] The actual range achieved by a given link will depend on the qualities of the devices at both ends of the link, as well as the air conditions in between, and other factors.

The effective range varies depending on propagation conditions, material coverage, production sample variations, antenna configurations and battery conditions. Most Bluetooth applications are for indoor conditions, where attenuation of walls and signal fading due to signal reflections make the range far lower than specified line-of-sight ranges of the Bluetooth products.

Most Bluetooth applications are battery-powered Class 2 devices, with little difference in range whether the other end of the link is a Class 1 or Class 2 device as the lower-powered device tends to set the range limit. In some cases the effective range of the data link can be extended when a Class 2 device is connecting to a Class 1 transceiver with both higher sensitivity and transmission power than a typical Class 2 device.[23] Mostly, however, the Class 1 devices have a similar sensitivity to Class 2 devices. Connecting two Class 1 devices with both high sensitivity and high power can allow ranges far in excess of the typical 100m, depending on the throughput required by the application. Some such devices allow open field ranges of up to 1 km and beyond between two similar devices without exceeding legal emission limits.[24][25][26]

The Bluetooth Core Specification mandates a range of not less than 10 metres (33 ft), but there is no upper limit on actual range. Manufacturers' implementations can be tuned to provide the range needed for each case.[2]

Bluetooth profile[edit]

To use Bluetooth wireless technology, a device must be able to interpret certain Bluetooth profiles, which are definitions of possible applications and specify general behaviors that Bluetooth-enabled devices use to communicate with other Bluetooth devices. These profiles include settings to parameterize and to control the communication from the start. Adherence to profiles saves the time for transmitting the parameters anew before the bi-directional link becomes effective. There are a wide range of Bluetooth profiles that describe many different types of applications or use cases for devices.[27][28]

List of applications[edit]

A typical Bluetooth mobile phone headset
  • Wireless control and communication between a mobile phone and a handsfreeheadset. This was one of the earliest applications to become popular.[29]
  • Wireless control of and communication between a mobile phone and a Bluetooth compatible car stereo system (and sometimes between the SIM card and the car phone[30][31]).
  • Wireless communication between a smartphone and a smart lock for unlocking doors.
  • Wireless control of and communication with iOS and Android device phones, tablets and portable wireless speakers.[32]
  • Wireless Bluetooth headset and Intercom. Idiomatically, a headset is sometimes called "a Bluetooth".
  • Wireless streaming of audio to headphones with or without communication capabilities.
  • Wireless streaming of data collected by Bluetooth-enabled fitness devices to phone or PC.[33]
  • Wireless networking between PCs in a confined space and where little bandwidth is required.[34]
  • Wireless communication with PC input and output devices, the most common being the mouse, keyboard and printer.
  • Transfer of files, contact details, calendar appointments, and reminders between devices with OBEX.
  • Replacement of previous wired RS-232 serial communications in test equipment, GPS receivers, medical equipment, bar code scanners, and traffic control devices.
  • For controls where infrared was often used.
  • For low bandwidth applications where higher USB bandwidth is not required and cable-free connection desired.
  • Sending small advertisements from Bluetooth-enabled advertising hoardings to other, discoverable, Bluetooth devices.[35]
  • Wireless bridge between two Industrial Ethernet (e.g., PROFINET) networks.
  • Seventh and eighth generationgame consoles such as Nintendo's Wii,[36] and Sony's PlayStation 3 use Bluetooth for their respective wireless controllers.
  • Dial-up internet access on personal computers or PDAs using a data-capable mobile phone as a wireless modem.
  • Short-range transmission of health sensor data from medical devices to mobile phone, set-top box or dedicated telehealth devices.[37][38]
  • Allowing a DECT phone to ring and answer calls on behalf of a nearby mobile phone.
  • Real-time location systems (RTLS) are used to track and identify the location of objects in real time using "Nodes" or "tags" attached to, or embedded in, the objects tracked, and "Readers" that receive and process the wireless signals from these tags to determine their locations.[39]
  • Personal security application on mobile phones for prevention of theft or loss of items. The protected item has a Bluetooth marker (e.g., a tag) that is in constant communication with the phone. If the connection is broken (the marker is out of range of the phone) then an alarm is raised. This can also be used as a man overboard alarm. A product using this technology has been available since 2009.[40]
  • Calgary, Alberta, Canada's Roads Traffic division uses data collected from travelers' Bluetooth devices to predict travel times and road congestion for motorists.[41]
  • Wireless transmission of audio (a more reliable alternative to FM transmitters)
  • Live video streaming to the visual cortical implant device by Nabeel Fattah in Newcastle university 2017.[42]
  • Connection of motion controllers to a PC when using VR headsets

Bluetooth vs Wi-Fi (IEEE 802.11)[edit]

Bluetooth and Wi-Fi (Wi-Fi is the brand name for products using IEEE 802.11 standards) have some similar applications: setting up networks, printing, or transferring files. Wi-Fi is intended as a replacement for high-speed cabling for general local area network access in work areas or home. This category of applications is sometimes called wireless local area networks (WLAN). Bluetooth was intended for portable equipment and its applications. The category of applications is outlined as the wireless personal area network (WPAN). Bluetooth is a replacement for cabling in a variety of personally carried applications in any setting, and also works for fixed location applications such as smart energy functionality in the home (thermostats, etc.).

Wi-Fi and Bluetooth are to some extent complementary in their applications and usage. Wi-Fi is usually access point-centered, with an asymmetrical client-server connection with all traffic routed through the access point, while Bluetooth is usually symmetrical, between two Bluetooth devices. Bluetooth serves well in simple applications where two devices need to connect with a minimal configuration like a button press, as in headsets and remote controls, while Wi-Fi suits better in applications where some degree of client configuration is possible and high speeds are required, especially for network access through an access node. However, Bluetooth access points do exist, and ad-hoc connections are possible with Wi-Fi though not as simply as with Bluetooth. Wi-Fi Direct was recently developed to add a more Bluetooth-like ad-hoc functionality to Wi-Fi.[43]

Devices[edit]

A Bluetooth USB dongle with a 100 m range

Bluetooth exists in numerous products such as telephones, speakers, tablets, media players, robotics systems, laptops, and console gaming equipment as well as some high definition headsets, modems, hearing aids[44] and even watches.[45] Given the variety of devices which use the Bluetooth, coupled with the contemporary deprecation of headphone jacks by Apple, Google, and other companies, and the lack of regulation by the FCC, the technology is prone to interference.[46] Nonetheless Bluetooth is useful when transferring information between two or more devices that are near each other in low-bandwidth situations. Bluetooth is commonly used to transfer sound data with telephones (i.e., with a Bluetooth headset) or byte data with hand-held computers (transferring files).

Bluetooth protocols simplify the discovery and setup of services between devices.[47] Bluetooth devices can advertise all of the services they provide.[48] This makes using services easier, because more of the security, network address and permission configuration can be automated than with many other network types.[47]

Computer requirements[edit]

A typical Bluetooth USB dongle
An internal notebook Bluetooth card (14×36×4 mm)

A personal computer that does not have embedded Bluetooth can use a Bluetooth adapter that enables the PC to communicate with Bluetooth devices. While some desktop computers and most recent laptops come with a built-in Bluetooth radio, others require an external adapter, typically in the form of a small USB "dongle."

Unlike its predecessor, IrDA, which requires a separate adapter for each device, Bluetooth lets multiple devices communicate with a computer over a single adapter.[49]

Operating system implementation[edit]

For Microsoft platforms, Windows XP Service Pack 2 and SP3 releases work natively with Bluetooth v1.1, v2.0 and v2.0+EDR.[50] Previous versions required users to install their Bluetooth adapter's own drivers, which were not directly supported by Microsoft.[51] Microsoft's own Bluetooth dongles (packaged with their Bluetooth computer devices) have no external drivers and thus require at least Windows XP Service Pack 2. Windows Vista RTM/SP1 with the Feature Pack for Wireless or Windows Vista SP2 work with Bluetooth v2.1+EDR.[50] Windows 7 works with Bluetooth v2.1+EDR and Extended Inquiry Response (EIR).[50] The Windows XP and Windows Vista/Windows 7 Bluetooth stacks support the following Bluetooth profiles natively: PAN, SPP, DUN, HID, HCRP. The Windows XP stack can be replaced by a third party stack that supports more profiles or newer Bluetooth versions. The Windows Vista/Windows 7 Bluetooth stack supports vendor-supplied additional profiles without requiring that the Microsoft stack be replaced.[50] It is generally recommended to install the latest vendor driver and its associated stack to be able to use the Bluetooth device at its fullest extent.

Apple products have worked with Bluetooth since Mac OS X v10.2, which was released in 2002.[52]

Linux has two popular Bluetooth stacks, BlueZ and Fluoride. The BlueZ stack is included with most Linux kernels and was originally developed by Qualcomm.[53] Fluoride, earlier known as Bluedroid is included in Android OS and was originally developed by Broadcom.[54] There is also Affix stack, developed by Nokia. It was once popular, but has not been updated since 2005.[55]

FreeBSD has included Bluetooth since its v5.0 release, implemented through netgraph.[56]

NetBSD has included Bluetooth since its v4.0 release.[57] Its Bluetooth stack was ported to OpenBSD as well, however OpenBSD later removed it as unmaintained.[58][59]

DragonFly BSD has had NetBSD's Bluetooth implementation since 1.11 (2008).[60] A netgraph-based implementation from FreeBSD has also been available in the tree, possibly disabled until 2014-11-15, and may require more work.[61][62]

Specifications and features[edit]

The specifications were formalized by the Bluetooth Special Interest Group (SIG) and formally announced on 20 May 1998.[63] Today it has a membership of over 30,000 companies worldwide.[64] It was established by Ericsson, IBM, Intel, Nokia and Toshiba, and later joined by many other companies.

All versions of the Bluetooth standards support downward compatibility.[65] That lets the latest standard cover all older versions.

The Bluetooth Core Specification Working Group (CSWG) produces mainly 4 kinds of specifications:

  • The Bluetooth Core Specification, release cycle is typically a few years in between
  • Core Specification Addendum (CSA), release cycle can be as tight as a few times per year
  • Core Specification Supplements (CSS), can be released very quickly
  • Errata (Available with a user account: Errata login)

Bluetooth 1.0 and 1.0B[edit]

Versions 1.0 and 1.0B[citation needed] had many problems, and manufacturers had difficulty making their products interoperable. Versions 1.0 and 1.0B also included mandatory Bluetooth hardware device address (BD_ADDR) transmission in the Connecting process (rendering anonymity impossible at the protocol level), which was a major setback for certain services planned for use in Bluetooth environments.

Bluetooth 1.1[edit]

Bluetooth 1.2[edit]

Major enhancements include:

Bluetooth 2.0 + EDR[edit]

This version of the Bluetooth Core Specification was released before 2005. The main difference is the introduction of an Enhanced Data Rate (EDR) for faster data transfer. The bit rate of EDR is 3 Mbit/s, although the maximum data transfer rate (allowing for inter-packet time and acknowledgements) is 2.1 Mbit/s.[67] EDR uses a combination of GFSK and phase-shift keying modulation (PSK) with two variants, π/4-DQPSK and 8-DPSK.[69] EDR can provide a lower power consumption through a reduced duty cycle.

The specification is published as Bluetooth v2.0 + EDR, which implies that EDR is an optional feature. Aside from EDR, the v2.0 specification contains other minor improvements, and products may claim compliance to "Bluetooth v2.0" without supporting the higher data rate. At least one commercial device states "Bluetooth v2.0 without EDR" on its data sheet.[70]

Bluetooth 2.1 + EDR[edit]

Bluetooth Core Specification Version 2.1 + EDR was adopted by the Bluetooth SIG on 26 July 2007.[69]

The headline feature of v2.1 is secure simple pairing (SSP): this improves the pairing experience for Bluetooth devices, while increasing the use and strength of security.[71]

Version 2.1 allows various other improvements, including extended inquiry response (EIR), which provides more information during the inquiry procedure to allow better filtering of devices before connection; and sniff subrating, which reduces the power consumption in low-power mode.

Bluetooth 3.0 + HS[edit]

Version 3.0 + HS of the Bluetooth Core Specification[69] was adopted by the Bluetooth SIG on 21 April 2009. Bluetooth v3.0 + HS provides theoretical data transfer speeds of up to 24 Mbit/s, though not over the Bluetooth link itself. Instead, the Bluetooth link is used for negotiation and establishment, and the high data rate traffic is carried over a colocated 802.11 link.

The main new feature is AMP (Alternative MAC/PHY), the addition of 802.11 as a high-speed transport. The high-speed part of the specification is not mandatory, and hence only devices that display the "+HS" logo actually support Bluetooth over 802.11 high-speed data transfer. A Bluetooth v3.0 device without the "+HS" suffix is only required to support features introduced in Core Specification Version 3.0[72] or earlier Core Specification Addendum 1.[73]

L2CAP Enhanced modes
Enhanced Retransmission Mode (ERTM) implements reliable L2CAP channel, while Streaming Mode (SM) implements unreliable channel with no retransmission or flow control. Introduced in Core Specification Addendum 1.
Alternative MAC/PHY
Enables the use of alternative MAC and PHYs for transporting Bluetooth profile data. The Bluetooth radio is still used for device discovery, initial connection and profile configuration. However, when large quantities of data must be sent, the high-speed alternative MAC PHY 802.11 (typically associated with Wi-Fi) transports the data. This means that Bluetooth uses proven low power connection models when the system is idle, and the faster radio when it must send large quantities of data. AMP links require enhanced L2CAP modes.
Unicast Connectionless Data
Permits sending service data without establishing an explicit L2CAP channel. It is intended for use by applications that require low latency between user action and reconnection/transmission of data. This is only appropriate for small amounts of data.
Enhanced Power Control
Updates the power control feature to remove the open loop power control, and also to clarify ambiguities in power control introduced by the new modulation schemes added for EDR. Enhanced power control removes the ambiguities by specifying the behaviour that is expected. The feature also adds closed loop power control, meaning RSSI filtering can start as the response is received. Additionally, a "go straight to maximum power" request has been introduced. This is expected to deal with the headset link loss issue typically observed when a user puts their phone into a pocket on the opposite side to the headset.

Ultra-wideband[edit]

The high-speed (AMP) feature of Bluetooth v3.0 was originally intended for UWB, but the WiMedia Alliance, the body responsible for the flavor of UWB intended for Bluetooth, announced in March 2009 that it was disbanding, and ultimately UWB was omitted from the Core v3.0 specification.[74]

On 16 March 2009, the WiMedia Alliance announced it was entering into technology transfer agreements for the WiMedia Ultra-wideband (UWB) specifications. WiMedia has transferred all current and future specifications, including work on future high-speed and power-optimized implementations, to the Bluetooth Special Interest Group (SIG), Wireless USB Promoter Group and the USB Implementers Forum. After successful completion of the technology transfer, marketing, and related administrative items, the WiMedia Alliance ceased operations.[75][76][77][78][79]

In October 2009 the Bluetooth Special Interest Group suspended development of UWB as part of the alternative MAC/PHY, Bluetooth v3.0 + HS solution. A small, but significant, number of former WiMedia members had not and would not sign up to the necessary agreements for the IP transfer. The Bluetooth SIG is now in the process of evaluating other options for its longer term roadmap.[80][81][82]

Bluetooth 4.0[edit]

The Bluetooth SIG completed the Bluetooth Core Specification version 4.0 (called Bluetooth Smart) and has been adopted as of 30 June 2010[update]. It includes Classic Bluetooth, Bluetooth high speed and Bluetooth Low Energy (BLE) protocols. Bluetooth high speed is based on Wi-Fi, and Classic Bluetooth consists of legacy Bluetooth protocols.

Bluetooth Low Energy, previously known as Wibree,[83] is a subset of Bluetooth v4.0 with an entirely new protocol stack for rapid build-up of simple links. As an alternative to the Bluetooth standard protocols that were introduced in Bluetooth v1.0 to v3.0, it is aimed at very low power applications powered by a coin cell. Chip designs allow for two types of implementation, dual-mode, single-mode and enhanced past versions.[84] The provisional names Wibree and Bluetooth ULP (Ultra Low Power) were abandoned and the BLE name was used for a while. In late 2011, new logos "Bluetooth Smart Ready" for hosts and "Bluetooth Smart" for sensors were introduced as the general-public face of BLE.[85]

Compared to Classic Bluetooth, Bluetooth Low Energy is intended to provide considerably reduced power consumption and cost while maintaining a similar communication range. In terms of lengthening the battery life of Bluetooth devices, BLE represents a significant progression.

  • In a single-mode implementation, only the low energy protocol stack is implemented. Dialog Semiconductor,[86] STMicroelectronics,[87] AMICCOM,[88]CSR,[89]Nordic Semiconductor[90] and Texas Instruments[91] have released single mode Bluetooth Low Energy solutions.
  • In a dual-mode implementation, Bluetooth Smart functionality is integrated into an existing Classic Bluetooth controller. As of March 2011[update], the following semiconductor companies have announced the availability of chips meeting the standard: Qualcomm-Atheros, CSR, Broadcom[92][93] and Texas Instruments. The compliant architecture shares all of Classic Bluetooth's existing radio and functionality resulting in a negligible cost increase compared to Classic Bluetooth.

Cost-reduced single-mode chips, which enable highly integrated and compact devices, feature a lightweight Link Layer providing ultra-low power idle mode operation, simple device discovery, and reliable point-to-multipoint data transfer with advanced power-save and secure encrypted connections at the lowest possible cost.

General improvements in version 4.0 include the changes necessary to facilitate BLE modes, as well the Generic Attribute Profile (GATT) and Security Manager (SM) services with AES Encryption.

Core Specification Addendum 2 was unveiled in December 2011; it contains improvements to the audio Host Controller Interface and to the High Speed (802.11) Protocol Adaptation Layer.

Core Specification Addendum 3 revision 2 has an adoption date of 24 July 2012.

Core Specification Addendum 4 has an adoption date of 12 February 2013.

Bluetooth 4.1[edit]

The Bluetooth SIG announced formal adoption of the Bluetooth v4.1 specification on 4 December 2013. This specification is an incremental software update to Bluetooth Specification v4.0, and not a hardware update. The update incorporates Bluetooth Core Specification Addenda (CSA 1, 2, 3 & 4) and adds new features that improve consumer usability. These include increased co-existence support for LTE, bulk data exchange rates—and aid developer innovation by allowing devices to support multiple roles simultaneously.[94]

New features of this specification include:

  • Mobile Wireless Service Coexistence Signaling
  • Train Nudging and Generalized Interlaced Scanning
  • Low Duty Cycle Directed Advertising
  • L2CAP Connection Oriented and Dedicated Channels with Credit-Based Flow Control
  • Dual Mode and Topology
  • LE Link Layer Topology
  • 802.11n PAL
  • Audio Architecture Updates for Wide Band Speech
  • Fast Data Advertising Interval
  • Limited Discovery Time[95]

Notice that some features were already available in a Core Specification Addendum (CSA) before the release of v4.1.

Bluetooth 4.2[edit]

Released on 2 December 2014, it introduces features for the Internet of Things.

The major areas of improvement are:

Older Bluetooth hardware may receive 4.2 features such as Data Packet Length Extension and improved privacy via firmware updates.[96][97]

Bluetooth 5[edit]

The Bluetooth SIG released Bluetooth 5 on 6 December 2016. Its new features are mainly focused on new Internet of Things technology. Sony was the first to announce Bluetooth 5.0 support with its Xperia XZ Premium in Feb 2017 during the Mobile World Congress 2017.[98] The Samsung Galaxy S8 launched with Bluetooth 5 support in April 2017. In September 2017, the iPhone 8, 8 Plus and iPhone X launched with Bluetooth 5 support as well. Apple also integrated Bluetooth 5 in its new HomePod offering released on 9 February 2018.[99] Marketing drops the point number; so that it is just "Bluetooth 5" (unlike Bluetooth 4.0).[citation needed] The change is for the sake of "Simplifying our marketing, communicating user benefits more effectively and making it easier to signal significant technology updates to the market."[100]

Bluetooth 5 provides, for BLE, options that can double the speed (2 Mbit/s burst) at the expense of range, or up to fourfold the range at the expense of data rate. The increase in transmissions could be important for Internet of Things devices, where many nodes connect throughout a whole house. Bluetooth 5 adds functionality for connectionless services such as location-relevant navigation[101] of low-energy Bluetooth connections.[102][103][104]

The major areas of improvement are:

  • Slot Availability Mask (SAM)
  • 2 Mbit/s PHY for LE
  • LE Long Range
  • High Duty Cycle Non-Connectable Advertising
  • LE Advertising Extensions
  • LE Channel Selection Algorithm #2

Features Added in CSA5 – Integrated in v5.0:

The following features were removed in this version of the specification:

Bluetooth 5.1[edit]

The Bluetooth SIG presented Bluetooth 5.1 on 21 January 2019.

The major areas of improvement are:

  • Angle of Arrival (AoA) and Angle of Departure (AoD) which are used for location and tracking of devices
  • Advertising Channel Index
  • GATT Caching
  • Minor Enhancements batch 1:
    • HCI support for debug keys in LE Secure Connections
    • Sleep clock accuracy update mechanism
    • ADI field in scan response data
    • Interaction between QoS and Flow Specification
    • Block Host channel classification for secondary advertising
    • Allow the SID to appear in scan response reports
    • Specify the behavior when rules are violated
  • Periodic Advertising Sync Transfer

Features Added in Core Specification Addendum (CSA) 6 – Integrated in v5.1:

The following features were removed in this version of the specification:

Bluetooth 5.2[edit]

On 31 December 2019, the Bluetooth SIG published the Bluetooth Core Specification Version 5.2. The new specification adds new features:[106]

  • LE Audio: Announced in January 2020 at CES by the Bluetooth SIG, LE Audio will run on the Bluetooth Low Energy radio lowering battery consumption, and allow the protocol to carry sound and add features such as one set of headphones connecting to multiple audio sources or multiple headphones connecting to one source[107][108] It uses a new LC3 codec. BLE Audio will also add support for hearing aids.[109]
  • Enhanced Attribute Protocol (EATT), an improved version of the Attribute Protocol (ATT)
  • LE Power Control
  • LE Isochronous Channels

Technical information[edit]

Architecture[edit]

Software[edit]

Seeking to extend the compatibility of Bluetooth devices, the devices that adhere to the standard use an interface called HCI (Host Controller Interface) between the host device (e.g. laptop, phone) and the Bluetooth device (e.g. Bluetooth wireless headset).

High-level protocols such as the SDP (Protocol used to find other Bluetooth devices within the communication range, also responsible for detecting the function of devices in range), RFCOMM (Protocol used to emulate serial port connections) and TCS (Telephony control protocol) interact with the baseband controller through the L2CAP Protocol (Logical Link Control and Adaptation Protocol). The L2CAP protocol is responsible for the segmentation and reassembly of the packets.

Hardware[edit]

The hardware that makes up the Bluetooth device is made up of, logically, two parts; which may or may not be physically separate. A radio device, responsible for modulating and transmitting the signal; and a digital controller. The digital controller is likely a CPU, one of whose functions is to run a Link Controller; and interfaces with the host device; but some functions may be delegated to hardware. The Link Controller is responsible for the processing of the baseband and the management of ARQ and physical layer FEC protocols. In addition, it handles the transfer functions (both asynchronous and synchronous), audio coding (e.g. SBC (codec)) and data encryption. The CPU of the device is responsible for attending the instructions related to Bluetooth of the host device, in order to simplify its operation. To do this, the CPU runs software called Link Manager that has the function of communicating with other devices through the LMP protocol.

A Bluetooth device is a short-rangewireless device. Bluetooth devices are fabricated on RF CMOSintegrated circuit (RF circuit) chips.[5][110]

Bluetooth protocol stack[edit]

Bluetooth is defined as a layer protocol architecture consisting of core protocols, cable replacement protocols, telephony control protocols, and adopted protocols.[111] Mandatory protocols for all Bluetooth stacks are LMP, L2CAP and SDP. In addition, devices that communicate with Bluetooth almost universally can use these protocols: HCI and RFCOMM.[citation needed]

Link Manager[edit]

The Link Manager (LM) is the system that manages establishing the connection between devices. It is responsible for the establishment, authentication and configuration of the link. The Link Manager locates other managers and communicates with them via the management protocol of the LMP link. In order to perform its function as a service provider, the LM uses the services included in the Link Controller (LC). The Link Manager Protocol basically consists of a number of PDUs (Protocol Data Units) that are sent from one device to another. The following is a list of supported services:

  • Transmission and reception of data.
  • Name request
  • Request of the link addresses.
  • Establishment of the connection.
  • Authentication.
  • Negotiation of link mode and connection establishment.

Host Controller Interface[edit]

The Host Controller Interface provides a command interface for the controller and for the link manager, which allows access to the hardware status and control registers. This interface provides an access layer for all Bluetooth devices. The HCI layer of the machine exchanges commands and data with the HCI firmware present in the Bluetooth device. One of the most important HCI tasks that must be performed is the automatic discovery of other Bluetooth devices that are within the coverage radius.

Logical Link Control and Adaptation Protocol[edit]

The Logical Link Control and Adaptation Protocol (L2CAP) is used to multiplex multiple logical connections between two devices using different higher level protocols. Provides segmentation and reassembly of on-air packets.

In Basic mode, L2CAP provides packets with a payload configurable up to 64 kB, with 672 bytes as the default MTU, and 48 bytes as the minimum mandatory supported MTU.

In Retransmission and Flow Control modes, L2CAP can be configured either for isochronous data or reliable data per channel by performing retransmissions and CRC checks.

Bluetooth Core Specification Addendum 1 adds two additional L2CAP modes to the core specification. These modes effectively deprecate original Retransmission and Flow Control modes:

Enhanced Retransmission Mode (ERTM)
This mode is an improved version of the original retransmission mode. This mode provides a reliable L2CAP channel.
Streaming Mode (SM)
This is a very simple mode, with no retransmission or flow control. This mode provides an unreliable L2CAP channel.

Reliability in any of these modes is optionally and/or additionally guaranteed by the lower layer Bluetooth BDR/EDR air interface by configuring the number of retransmissions and flush timeout (time after which the radio flushes packets). In-order sequencing is guaranteed by the lower layer.

Only L2CAP channels configured in ERTM or SM may be operated over AMP logical links.

Service Discovery Protocol[edit]

The Service Discovery Protocol (SDP) allows a device to discover services offered by other devices, and their associated parameters. For example, when you use a mobile phone with a Bluetooth headset, the phone uses SDP to determine which Bluetooth profiles the headset can use (Headset Profile, Hands Free Profile (HFP), Advanced Audio Distribution Profile (A2DP) etc.) and the protocol multiplexer settings needed for the phone to connect to the headset using each of them. Each service is identified by a Universally Unique Identifier (UUID), with official services (Bluetooth profiles) assigned a short form UUID (16 bits rather than the full 128).

Radio Frequency Communications[edit]

Radio Frequency Communications (RFCOMM) is a cable replacement protocol used for generating a virtual serial data stream. RFCOMM provides for binary data transport and emulates EIA-232 (formerly RS-232) control signals over the Bluetooth baseband layer, i.e., it is a serial port emulation.

RFCOMM provides a simple, reliable, data stream to the user, similar to TCP. It is used directly by many telephony related profiles as a carrier for AT commands, as well as being a transport layer for OBEX over Bluetooth.

Many Bluetooth applications use RFCOMM because of its widespread support and publicly available API on most operating systems. Additionally, applications that used a serial port to communicate can be quickly ported to use RFCOMM.

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