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Bluetooth Low-Energy for the NextGen Networks

It may sound a bit like a cheerleader chant for a high school sports event, but it really is going to be one of the topmost enabling technologies for the next-generation networks.

By Ernest Worthman, Executive Editor, Small Cell Magazine

May 12, 2016 — Bluetooth low-energy (BLE), also referred to as Bluetooth low-power, and Bluetooth smart, as the Bluetooth SIG is calling it, is one of the top emerging disruptive technologies for the next generation of wireless networks, especially the IoE. BLE will enable the next level of IoE vertical devices, such as medical devices, home automation, retail, wearables, and much more.

ble-01For consumers, it comes down to the Internet of Your Things (IoYT – yet another iteration in the craze to find a personalized moniker for your corner of the IoE world). You wake up and go for a run with a heart rate monitor that speaks directly to your smart watch. You brush your teeth with a sensor toothbrush while listening to music through your showerhead. Your computer senses you just sat down in front of it and it turns itself on. You watch your kids play basketball with a “smart” ball that analyses their play style. You unlock your doors, turn on the lights, and run your TV with your smart phone or your wearable BLE device (which interfaces with your smart phone). And that is only a partial laundry list of devices that can integrate a Bluetooth module.

The Rundown

Fortunately, BLE, formally known as Bluetooth 4.0 is an extension of the classic BT technology. BLE was developed as an ultra-low, short range (three -10 m1) wireless protocol for energy stingy application and disposable devices. Says Kroeter, when we developed it, fundamentally, it brought two things to the table. The first being orders of magnitude of better power efficiency, and second, it offers a flexible application development environment.”

The nice (and smart) thing about BLE is that it inherits all the functionality, standards, and interoperability that its parent, BT classic has. That means developing for the BLE platform has a lot of technology that can be ported. It is just designed to use less energy.

BLE is designed to be exactly the opposite of its bigger, faster brothers, 1.2, 2.0 + EDR (the enhanced data rate version), and 3.0 +HS (the high speed version). BLE is designed for small data-transfer payloads with low duty cycles. “Where classic Bluetooth devices can run on a couple of AA batteries for a couple of months, the smart version can run on a coin cell for a couple of years,” says Kroeter.

There is some question as to where BLE will find a niche among some many competing technologies (Wi-Fi, ZigBee) but there certainly seem to be some applications, such as the body area network (BAN) where the network is constrained to a very small perimeter bubble around the body (sports, medical, gaming, implants, wearables, etc.). It can also work for other platforms such as computers (keyboards, mice) and is a promising platform for many types of sensors in the IoE, especially those that might not be viable if frequency battery change-outs are required.

The Drill Down

Peeling back the layers and looking at the technology finds that the design reuses much of the existing framework for BT radios, including the 2.4 GHz ISM band. That means it is backwards compatible with all existing BT designs. Following is a laundry list of specifications, and we will dissect some of them a bit further on. A table of more precise specifications is given at the end of this article.

  • OTA data rate: 1 Mb/s.
  • Modulation scheme: GFSK2 with frequency hopping.
  • Channels: 40.
  • Max output power: +10 dBm.
  • Nominal output power: 0 dBm.
  • Major operational modes: advertising, scanning, master device and slave device.
  • Packet data transfers: 8-27 octets per packet.
  • Latency: down to 3 ms, 6 ms typical.
  • Robustness: 24-bit CRC per packet.
  • Built-in security: AES-128, with counter mode, CBC-MAC, and application layer user defined.
  • Topology: 32-bit scatternet, one to one and one to many.

BLE improves on classic BT in a number of areas that relate to power footprints. BLE boasts energy efficiencies of 20 times that of Classical BT, yet reduces power consumption by an order of magnitude in some places. It does this by using a number of schemes and a very simple link layer that is capable of a fast connect cycle. Typically, BLE devices spend only 1% of its time awake, (lowest sleep mode can will typically consume < 1.0 μA) and when it does wake, the idle current mode is a few 10s of μA, and when in data transmission mode, that peak current rises to 15 mA, max.

From the onset, BLE was designed with simplicity in mind. In order to achieve the lofty goals of minimal power consumption, BLE design focuses on applications and devices that need to transfer small quantities of data, over relatively short distances. That was accomplished with a new protocol stack that can, quickly, construct simple links. The process sets up an ultra-fast connection, followed by a short bursts of minute data packets, and an ultra-fast disconnect. This resembles a pulsed data transmission scheme and works extremely well for quick communication of data snippets such as “the temperature in the refrigerator has changed more than two degrees, or the room is no longer occupied.”

There are three main elements that are used to accomplish this. They are an intelligent host controller, and an adjustable duty cycle and message length. As far as the controller goes, being smart means it has the ability to monitor activity and respond only to activity that requires action specific to the host. That mean the host can remain in sleep mode much of the time.

The other two primary low energy components are the adjustable duty cycle and message length. The duty cycle can be adjusted down to as low as 0.1%. What that does is present app and device developers a minimal target to aim for to give them maximum run time, should that be their goal. The adjustable message variable gives the app the options of packaging messages in longer or shorter packages for efficiency. Reasoning is that longer single messages are more energy efficient than multiple short messages, mainly due to setup and tear down overhead, but other system parameters have an effect as well.

Another key parameter for efficiency is robustness. Frequency hopping is used because it is relatively immune to interference, thereby reducing redundancy requirements. This is particularly useful in multi-wireless environments, such as the home, or public wireless hotspots where multiple protocols exits (Wi-Fi, ZigBee, cellular, etc.).

The more cycles that wireless device has, the more latency becomes a factor, simply put, latency is created when the activity needs to add extra processing to the signal. This can be due to link budgets, signal or component instability, or signal strength. BLE addresses that by its simple architecture. I.e., small packets and simple protocols.

ble-02BLE is designed for small packet transmissions. Typically between 8 and 27 octets3 per data package. Additionally, connections implement sniff sub-rating4, which provides very low duty cycles

Perhaps the greatest doctrine of BLE is its simplicity. The layered GATT architecture (see Figure 2), simplifies creating and implementing profiles. Because ease of implementation was part of the initial design considerations, applications and embedded devices can be quickly fitted to the BLE architecture.

Channels and Protocol and Security

In addition to all the tricks used to reduce power, the most significant design feature is the channel configuration. The BLE mantra, simplicity, and economy is a result of fewer channels. This propagates throughout the design in producing the low-energy footprint. For example, BLE uses only three channels as advertising channels, where classic uses 32. This reduces time on air, which in turn reduces the power envelope. The three-channel design requires only 0.6 to 1.2 ms to scan for other devices, in contrast to the 22.5 ms and 32 channel scan that the classic version uses.

The protocols that BLE uses also contribute to BLE’s energy efficiency. Classic uses nine different protocols, BLE only one – the attribute protocol (ATT). This is a sequential configuration that allows only one request at a time. It is based on a client/server architecture that is a much simplified read/write protocol requiring significantly less power to run.

Finally, BT and BLE are a bit more secure, intrinsically, principally because the interconnect processes are between two paired devices. That requires an authentication process that, once initiated, provides relatively secure communications between the devices. Included in this security envelop are mechanisms for authentication, encryption, authorization, even man-in-the-middle protection.

BLE uses the industry-standard Diffie–Hellman, FIPS-compliant, encryption for key generation. And, once the keys are generated, and the data is encrypted with the 128-bit AES cipher.

What BLE Isn’t Good For

For all BLE seems to be a fit for, one must remember that BLE devices are a general classification of short messaging scenarios. BLE cannot be used for transmitting streaming content or long complex conversations. Generally, the baseline for BLE applications is that is needs to spend most of its time in the off state. For applications that meet that criterion, BLE is an ideal platform.

Flash — Bluetooth 4.2 Just Released

Bluetooth 4.2 is a just released (Dec 2014) update to the core 4.0 specification. Four dot two expands upon the 4.0 by adding support for low power IP (IPv6 and 6LoWpan). This adds some new flexibility and enables IoE connectivity. It also adds a bit more intelligence in the form of security. With this update, a Bluetooth smart location tracker can only be followed by the owner or trusted group. And finally, the data bandwidth has been increased. Throughput has been increased by a factor or up to 2.5X and packet capacity has been given a 10-fold uptick, so the total data payload is now 270 octets.

Missive

BLE promises to offer a low-cost, low-profile, ultra-low-power and ultra-efficient short messaging platform. The ubiquity of the market is still developing but there is promise in a number of areas such as sports, medical, PANs, sensors, etc.

As the IoE unfolds, there will be a significant amount of opportunity for communication between objects that fists this short-range, low duty cycle, low data packet envelope. Some areas, such as in-home automation, and in-vehicle communications are rich in exactly the type of communication BLE is designed for.

And, last but not least is the IoE. Low power will have a high value in the IoE. With so many possibilities, and so many devices, low energy will be a primary consideration. So the future for BLE cannot be anything but bright.


1. Theoretically, distances up to 200 ft. are possible, but for that to work, the ultra-low e

2. Gaussian Frequency Shift keying modes do not make use of PN codes. In this case, all devices on the same frequency can communicate with one another, and co-location capabilities are potentially reduced. GFSK mode is the fastest data rate. However, care must be taken in its use. Because this mode eliminates the advantage that DSSS technology has, making it much more susceptible to errors.

3. An octet is an 8-bit word. In most cases, it is the same as a byte. It is also commonly used to represent any of the four bytes of an IPv4 address.

4. Sniff sub-rating is a Bluetooth feature that enables paired devices to negotiate, based on usage, the frequency of sending “keep alive” messages to one another.

BLE VS. BT CLASSIC – TABLE OF SPECIFICATIONS
Specification Classic BLE
Channel Bandwidth 1 MHz 2 MHz
Channels 79 40
Data Rate 1-3 Mbps 1 Mbps
Frequency  2.4 – 2.483 GHz  2.4 – 2.483 GHz
Modulation Index 0.35 0.5
Modulation Scheme GFSK GFSK
Modulation Technique FHSS FHSS
Nodes Master/Slave 7 Unlimited
Security 56 to 128-bit 128-bit AES
Throughput 0.7-2.1 Mbps 0.3 Mbps

Bluetooth 4.0 Features IoE Focus

By Ernest Worthman

December 10, 2010 — The fourth version of the Bluetooth protocol, known as Bluetooth Smart or Bluetooth Low Energy (BLE), is placing a new focus on the Internet of Everything (IoE). The Bluetooth SIG (Special Interest Group) recently unveiled several of the IoE features being added to Bluetooth in 2016.

The planned upgrades include improvements in data transmission range and speed (four- and two-fold increases, respectively) without increasing energy consumption. The current version of Bluetooth Smart supports ultra-low peak, average and idle mode power consumption, allowing Bluetooth devices to run for a month on standard coin-cell batteries, the organization says. The Bluetooth standard can typically transmit data over a distance of 32.81 feet, but has the potential to send information up to 109.3 yards.

This is good news for a number of industries, wearables being one, which will now be able to better connect to the variety of small cell networks, such as smart homes, industrial automation, smart infrastructure, and mission-critical devices used in medicine and hospitals, while maintaining long battery life, according to the Bluetooth SIG.

Special Report – It’s Time to Address Smart Phone Security

By Ernest Worthman —

August 26, 2015 — For the longest time, securing wireless communication devices wasn’t high on the OEM’s priority list. And for much of that time, there really wasn’t much of a concern with security on phones, and smart devices in general. But that is starting to change. With the integration of Wi-Fi and web browsing, the same miscreants that attack computer networks have a new vector to compromise data.

In general, the Android and Apple operating systems (OS) aren’t particularly hack-able so the operational components are safe. The value in hijacking a smart phone is in what’s on it and what else it can be used for, to attack. Their interest is in things like personal, financial, credit card, and other data, as well as to put it to use as a portal to other devices and systems. That is now possible using a smartphone.

But with Wi-Fi and Internet access, it isn’t just about your data. There is a virtual cornucopia of opportunity with all the social media that most people have on their smartphones. So if you’re hacked, everyone whose data is on your device is a potential target as well.

That is the gravity of the situation, and it is serious. Most consumers are aware of securing their PCs. But few realize that today’s mobile phones are just as vulnerable. And when the Internet of Everything (IoE) materializes, your smartphone will be connected to everything from smart socks to smart cars.

Just recently, a group of researchers from Indiana University, Peking University and the Georgia Institute of Technology revealed some deadly zero-day flaws in Apple’s iOS and OS X, claiming it is possible to crack Apple’s password-storing keychain, break app sandboxes and bypass its App Store security checks. Apple is supposedly not hackable. Well, so much for that theory. Similar conditions exist for Android, as well. And, simply put the term “smartphone hack” into any search engine; pages and pages come up on how to and what hacks are available.

An excellent overview of smartphone security overview, titled “A Window Into Mobile Device Security.” from Symantec. While this report is a few years old and some progress has been made towards addressing these flaws, a significant number of them still exist, in addition to new ones that have been discovered since then.

And another issue is just how easy it can be done. Recently, a cyber-company named iSEC partners demonstrated how texts, cell phone calls and other information were fully able to be disclosed on the Verizon smartphone through the use of a femtocell, which can be bought for under $300!

Today, there are three common methods of cell phone hacking: the first can be done, even when the phone is off, using peripheral technology such as Bluetooth. Hackers can still access your info without your even being aware of it.

Another method, and this has risen to the top of late, is the use of mini-cell phone towers where outsiders can read off cell phone data, or spoofed cell towers (devices that fool the phone into thinking it is talking to a real tower).

Another method of hacking into phones is to reroute the info to an outside source, typically referred to as “man in the middle. This is when a person can get into your phone’s operating system and pass the information onto unscrupulous persons who just wait for information to come to them.

We are just scratching the surface, here. But the time has come to start taking smartphone security very seriously. With the IoE, the potential for expanded threats ramps up by orders of magnitude because the devices that will be interconnected will be expanded by those same orders of magnitude.

Meanwhile, there are some things one can do to keep the possibility of being hacked to a minimum:

  • Storing and sharing information on your phone is very risky and is something that is done autonomously. So the first thing to do is know what is on your smartphone and if there are ways to password or secure them.
  • Keep the phone close and in a secure place that is difficult for thieves to get to. If there is suspicion that the phone has been hacked, or it has been stolen, contact your service provider ASAP.
  • Use a strong password to lock, or unlock your phone (1234 or 0000 just isn’t smart, ya know).
  • Bluetooth is a very easy method for hackers to get to into a phone. It doesn’t take a crack criminal to hack through this veil. The best idea is to turn Bluetooth off unless it is in use. That may be a bit of a hassle, but much better than what can happen.
  • Use anti-virus software if available, and keep it updated. But make sure the download link is legitimate. Something as simple as downloading a link from email on your phone can cause it to pick up a virus.

The point here is that it is time to understand that smartphones aren’t any less vulnerable to hacking than computers or other networks. It just hasn’t come into the center of the radar screen, yet…but it will. Let’s hope we are prepared.