Published on: March 29, 2016

Coming Bluetooth extensions will make the wireless technology a better fit for smart lighting, explains MAREK WIERZBICKI, while mesh extensions will retain the low power, ease of use, and reliability of the proven radio technology.

Smart lighting might be the biggest revolution the lighting industry has seen in decades, but the multitude of available wireless communication technologies can cause a real headache for manufacturers willing to delve into this new, exciting market. Bluetooth is the latest talk of the town with its mesh networking support to be adopted later this year. We at Silvair have been deeply involved in the Bluetooth Smart Mesh Working Group`s efforts aimed at standardizing a Bluetooth-based mesh architecture, and this examination of the basic concepts behind one approach to a Bluetooth Mesh implementation will give you an idea as to what Bluetooth Smart mesh networking is all about.

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Lighting standards we`ve all known for years are now being challenged by the next generation of lighting systems that promise to deliver so much more than just a well-lit space. The transition toward digital lighting is happening right in front of our eyes, and while a couple of months ago many had doubts as to whether smart lighting could be a real deal, it now seems that there is no turning back. Over the last 12 months, we`ve seen multiple heavyweight lighting manufacturers spinning off big chunks of their traditional businesses to put more focus on connected technologies.  Smart lighting promises new business models with a steady stream of revenue from value-added features and services, which is exactly what lighting companies need to overcome the challenges resulting from the impressive longevity of LEDs and razor-thin margins in the LED market.

FIG. 1. There were a number of Bluetooth-based, mesh-enabled lighting products at the Consumer Electronics Show (CES) in 2016 including a lamp from Girard Sudron and a switch from NodOn.

Moving to networks

It is therefore not surprising that virtually every week we are hearing news about lighting manufacturers entering into agreements with companies that can relatively swiftly implement smart technologies into their products, or even straightforwardly acquiring providers of wireless connectivity, cloud services, or advanced data analytics. Things have gone so far that we`ve already seen Goldman Sachs downgrading its rating on one of the leading lighting manufacturers, citing concerns over the company`s deteriorating earnings and emphasizing its low exposure to connected technologies. The trend is clear: Lighting systems are becoming digital, and a wide variety of smart lighting products (Fig. 1) presented at CES (Consumer Electronics Show) 2016 only confirms this.

Bluetooth Classic versus Bluetooth Smart

All that noise surrounding Bluetooth might be somewhat confusing for those not too familiar with the recent developments in the wireless communication landscape. After all, the protocol was first developed before the term "Internet of Things" was even coined. But what many are still not aware of is that the Bluetooth of today is something completely different than Bluetooth of the past.

FIG. 2. Legacy Bluetooth has relied on a hub-and-spoke topology while commercial smart lighting will require a mesh network for communications.

The original Bluetooth, known as Bluetooth Classic, was designed as a short-range, cable-replacement technology for point-topoint communications. Initially, the main goal was to synchronize data between mobile phones, but the standard quickly became the default technology for wireless data exchange between personal computing equipment (mobile phones, PCs, PDAs) and peripherals (headsets, cordless keyboards and mice, printers, and such). Devices could form a tiny personal area network (PAN) called a piconet, whereby a single central device would coordinate the activity of up to seven active peripherals.

Meet a mesh

Silvair Mesh has been developed to allow users to build their smart mesh networks in which one or more mobile devices (smartphones/tablets) can control one or more mesh-enabled peripheral devices (e.g., lamps, sensors, dimmers, switches, etc.). When equipped with the mesh software stack, essentially an enhanced Bluetooth Smart stack, these devices can communicate with each other and the central controller via the Bluetooth Smart radio using the protocol`s standard mechanisms called GATT (Generic Attribute Profile). This means that all mesh-enabled peripherals can create their own autonomous mesh network that does not require any central device to operate.

FIG. 3. Smart mesh capabilities are added to Bluetooth devices in the network, transport, and application layers in software and don`t impact the physical and link layers that are captured in radio ICs and modules.

The decision to base Silvair Mesh on Bluetooth Smart was intentional, as it meant that the ecosystem would be compatible with all existing Bluetooth Smart devices and chipsets. However, a mesh stack also requires numerous additional features to standard Bluetooth Smart. For instance, the Silvair Mesh includes a high-performance Bluetooth controller and a new Network Security Manager, as well as the secure OverThe-Air Update functionality, which means that a device can be upgraded to the newest version of the firmware at any time.

Network setup

As will be required in commercial applications, the Silvair Mesh software allows networks of any size to be set up, but the way in which large and small networks are commissioned, is different. Small networks of up to about 30 devices can be commissioned and managed using just the app on a smartphone or a tablet. The plug-and-play nature of Bluetooth, and the fact that the protocol is natively supported by virtually all smartphones and tablets on the market, makes the entire process extremely simple and intuitive. The app detects and displays mesh devices in its vicinity. The user creates a mesh network by selecting which devices should be added, and by giving the network a name. Once added to the network, associations and relationships can be set up between the devices as desired. The smartphone can then be switched off and these connections will remain in place (Fig. 4).

FIG. 4. Silvair Mesh supports both smaller mesh networks controlled by a single smartphone and complex networks with dedicated cloud-connected servers.

Networks of over about 30 devices, or the ones requiring more sophisticated associations, scenarios, and network monitoring services, are best set up using some type of server or management appliance. In the case of Silvair, an embedded server called Silvair Logic hosts all the logic that controls the entire network, checks the status of all peripherals, and reports any issues and unusual events via a browser-based interface.

The Bluetooth difference

The question one might ask at this point is why the Bluetooth Smart mesh would be any better than other mesh protocols available on the market? Simply put, it`s all about the radio. Out of all low-power, low-bandwidth communication standards, none is even close to having such impressive qualities as Bluetooth Smart. This allows the protocol to address some of the most difficult issues in such challenging applications as smart lighting, where multicast, synchronous operation and responsiveness are among the must-have features.

We`ve tested many other technologies inside out, and we know exactly why the existing mesh protocols have failed to deliver the smart lighting experience to environments where reliability and scalability are top priorities. And we firmly believe that this year`s adoption of the Bluetooth Smart mesh standard might finally open the door for smart lighting networks to become widely deployed in professional applications.

<Source: LEDs Magazine>