Resources | LpR Article | Technologies | Smart Lighting & IoT | Bluetooth | Jan 31, 2019

Qualified Bluetooth Mesh – Making Lighting Controls Future-Proof

LpR 69 Article, page 88: At Lightfair USA, Siegfried Luger met with Patrick Durand, Worldwide Technical Director at Future Lighting Solutions. One of Mr. Durand’s striking statements was: “Basically, what we need is to future-proof lighting control.” This was the first time that this important aspect was so clearly addressed by a representative of the industry. This led us to asking Mr. Durand to provide LED professional with a technical article to clarify the current situation, explain the technical background that led him to making that statement and to give an idea of which requirements a controls solution must fulfill to be truly future-proof.

Building infrastructure is usually designed to last for decades. This is no different for lighting equipment. When a building owner or building manager decides to invest in lighting control they need to have the confidence that their decision is going to be the right one not just for the next couple of years, but for the next decade, or more. But today the bombardment of all the new technologies that are being introduced causes a building manager to say, “I’ll wait until the technology landscape matures where one technology wins.” With a future-proof lighting control system, there would be no need to have that type of concern. The idea sounds simple, but we need to figure out how to achieve it.

The Basics of a Future-Proof Installation

As a first step, it is necessary to start with a basic installation: a switch, a sensor/controller and nothing more. There shouldn’t be any gateways; no gateway for commissioning; no gateway for controlling. However, the system needs to be able to optionally add a gateway. The gateway, in this case, is just a protocol translator, nothing else. It is not like a ZigBee gateway/server for large installations where the ZigBee gateway manages the network and if the main gateway fails, there is potentially a single point of failure for the entire system. The future-proof lighting control gateway is simply a bridge from the wireless protocol to, say, a BACnet building management system, or KNX system, or Cloudbased system, or even a technology that’s going to be invented several years from now.

A simple optional protocol translator gateway gives the user the choice of what to do, when to do it and how far to go. If, during the initial installation of a lighting control system, the building manager is not ready for any complexity and just wants the switch and the controller, we need a wireless technology that supports these needs (Figure 1). But, if two years later he/she says, “My building is upgrading and a BACnet building automation system is being installed,” that should not pose any issues, whether the building automation system is from Schneider, Siemens, Johnson Control, Honeywell, or whomever. And the reason for the building manager’s peace of mind is that there is no need to change anything from the initial installation of wireless luminaires and switches other than adding a limited number of protocol translator gateways to seamlessly translate and forward data from the wireless protocol to the BACnet protocol. If five years later, the building manager realizes that he/she can no longer achieve his/her objectives with BACnet and wants to go to a Cloud-based system, he/she can simply change the limited number of BACnet gateways to Cloud-based gateways, and that’s it. You have a future-proof solution.

Wireless Technologies for a Future-Proof Installation

The topology of a wireless system makes all the difference in being able to future-proof a lighting control installation. If it supports point-topoint and point to multi-point, this means that the switch or sensor communicates directly to the controller, which is the wireless device that provides the signal to the LED driver to turn it on/off or to dim it to a specified level. It’s mainly EnOcean and Bluetooth that support this type of topology from an open standard standpoint (Figure 2).

Figure 2: Network topologies for lighting controlFigure 2: Network topologies for lighting control

With the new Qualified Bluetooth Mesh standard that was first released in July 2017, there is a mesh of nodes that can forward the data to other nodes in between the wireless switch/sensor to the wireless controller. Although the accurate name for the Bluetooth Mesh topology is many-to-many, one can still think of Bluetooth Mesh as supporting the point-topoint topology with the added benefit of being able to extend the range and reliability of the wireless network via meshing.

Technically, there are significant differences between Bluetooth Low Energy (LE) and Bluetooth Mesh standards, although they both leverage the same radio chip or radio module. It’s the ability of Qualified Bluetooth Mesh to relay the data that truly sets the two standards apart. Furthermore, for Bluetooth LE, security is optional where for Bluetooth Mesh, security is mandatory where it’s built into the standard where even the commissioning process itself is secure. From a similarity standpoint, the Bluetooth Mesh standard actually incorporates the entire Bluetooth LE functionality, which allows existing mobile devices with Bluetooth LE to directly connect to and control a Bluetooth Mesh network. And since gateways are optional devices in a Bluetooth Mesh network that can simply act as a protocol translator between Bluetooth Mesh and a building automation system or a Cloud service, Bluetooth Mesh can truly enable future-proof lighting control systems.

While the decision between EnOcean and Bluetooth Mesh is finally a question of personal preference, both systems have advantages and drawbacks. EnOcean is already installed in over 400,000 buildings. It’s a mature protocol. It’s an accepted protocol, particularly in HVAC and in lighting control. Another advantage of EnOcean is that it operates in the sub-GHz frequency range where the wireless signal can travel through walls further and there’s no risk of interference with any of the 2.4 GHz wireless systems in highly congested environments such as the center of New York City.

On the other hand, the benefit of Bluetooth over EnOcean is that it’s supported on every mobile device to directly communicate with the Bluetooth Mesh controller, which greatly simplifies the commissioning process. The other major benefit of Bluetooth technology is that it supports over-the-air updates, which has a future-proofing advantage over EnOcean. Finally, there is the cost advantage of Bluetooth Mesh since there are multiple Bluetooth radio and module vendors where there is only a single formal vendor of the EnOcean radio and modules. At the end of the day, cost is the number one barrier to the mainstream adoption of wireless lighting control solutions (assuming that the control solution is simple, reliable, scalable and secure). What the lighting industry needs are control solutions that are so cost effective, that lighting OEMs integrate a wireless controller in the luminaire regardless whether the end user (building manager) will immediately leverage the capabilities. With the scale and presence of Bluetooth, it’s mesh derivative is the only technology that has a realistic chance to live up to both the lowcost and future-proofing requirements for lighting control solutions.

It’s important to mention that at this time, Bluetooth Mesh is still a new standard that requires maturing and additional features before it can take the undisputed title of the dominant protocol for indoor commercial and industrial lighting control. This will still likely take a few more years to materialize but this is where the over-the-air updates functionality is such a critical capability. Furthermore, with Bluetooth 5, it’s now possible to increase the range of the Bluetooth signal up to a theoretical 240m, which should address most if not all concerns about range for the technology in indoor environments.

But for what it can do today with available Qualified Bluetooth Mesh end products like controllers, sensors and switches, end customers can start installing the core part of the future-proof lighting control systems. In the first half of 2019, we are expecting the launch of the first optional gateways to manage multiple sites and have advanced functionality such as occupancy heatmapping, asset tracking, beaconing, power consumption monitoring and more.

The interoperability of Bluetooth systems

Incompatibility is one of the major obstacles for a quick and mainstream adoption of lighting control systems. Currently, there are several proprietary lighting control systems on the market where some even leverage Bluetooth as their wireless radio where they are implementing a mesh network. Since the Qualified Bluetooth Mesh standard was only released in July 2017, many of these lighting control companies, where most are relatively small startups, had to develop their own proprietary technology. In many respects, some of these proprietary protocols are more advanced in functionality than the current version of the Qualified Bluetooth Mesh standard. As a result, the existing solutions that are leveraging a Bluetooth radio may wait until the Qualified Bluetooth Mesh standard matures before adopting it.

However, there is no doubt that Qualified Bluetooth Mesh will accelerate standardization and commoditization of wireless lighting control. The standard is written in a way that really promotes full interoperability, which is more than just at the user level. An example, in a retrofit project that includes luminaires from companies A (1000 lm downlights), B (2000 lm downlights), and C (4000 lm troffers): if they all include Qualified Bluetooth Mesh controllers, the contractor can install them like traditional luminaires and the building manager can easily commission and control them with the same mobile App or wireless wall-mount switch. Furthermore, the building owner will have the choice of leveraging different third party mobile Apps that will be flooding the market in the coming months and years. As a result, over time, there will be less differentiation at the hardware level where it will be the software functionality and user experience that will determine the adoption of a particular solution. With a fully interoperable standard, Qualified Bluetooth Mesh will drive down the cost and complexity of lighting control. The end goal is that the lighting OEM market will have sufficient choice of low cost and simple wireless control solutions where they will embed them into the luminaire as a standard offering regardless of whether the end customer takes immediate advantage of the added functionality or waits before enabling the wireless functionality. And as more Qualified Bluetooth Mesh solutions and luminaires are launched in the market, specifiers (Architects, Designers, Engineers) will start specifying Qualified Bluetooth Mesh for new building and retrofit projects. Once this occurs, that’s when the age of future-proof lighting control solutions will truly begin.

Security of Bluetooth Mesh solutions

Security is a mandatory part of the Bluetooth Mesh standard where all mesh messages are encrypted and authenticated. There are 3 types of security keys in Qualified Bluetooth Mesh. The first is the network key that is critical for a lighting node to join and send a message that will propagate through the mesh network. Furthermore, it’s possible to create sub networks (or zones like a conference room zone or receptionist zone) where each sub network has its own network key to enable a user to only have authority to control lights in his/her office but not for other offices in the building. The second is an application key so that a user who only has access to control lights cannot have access to the HVAC or other building systems. The third is the device key, which is important for removing a node from the network where the network and application keys are refreshed for the remaining nodes. This way, a discarded node (luminaire in the trashcan) cannot be used to attack the building network by a resourceful hacker.

Even with security, there are ways for lighting control vendors to go beyond the standard to differentiate themselves. For example, in an installation of luminaires from various luminaire vendors that are all leveraging Qualified Bluetooth Mesh, one approach is to automatically validate in the background of the commissioning process via the Cloud whether the node firmware contains any vulnerabilities or malware that can negatively impact the network before it is allowed to join it. No extra hardware devices would be required as the installer would leverage the same Internet connected mobile device for this enhanced commissioning process.

Is the multi-protocol approach valid?

Besides Bluetooth, Wi-Fi is also implemented in all mobile devices. And since Wi-Fi routers are found almost everywhere, it seems logical to leverage this infrastructure. The question is: is that really another direction we should consider or should we potentially consider a multiprotocol node to hedge our bets?

From a technical standpoint, it’s possible to have a wireless node that can support multiple protocols as there are several radio chips that support both Bluetooth and Wi-Fi and other chips that support both Bluetooth and 802.15.4 (ZigBee). However, one must remember that the difficult part in lighting control is not the hardware but rather the firmware and software. To support multiple protocols will necessarily add a significant level of complexity and may render the node incompatible with nodes from other vendors. Just like when it was unclear whether Blu-ray or HD-DVD would win the disc format war, some equipment vendors released expensive video players that supported both formats. However, the HD video disc industry only started to blossom when Blu-ray was declared the winner.

It’s important to understand the differences between Bluetooth vs. Wi-Fi and ZigBee and not attempt to employ a riskier multi-protocol node strategy at the luminaire level. Wi-Fi power consumption is higher than Bluetooth LE/Mesh and requires a router where we’ve all experienced router failures at home or in the office or at a hotel. For large scale ZigBee installations, gateways are required, which add a level of complexity and single points of failures since the gateways are managing the ZigBee network (Figure 3).

Figure 3: Architecture of a ZigBee Network (source: Synapse Wireless)Figure 3: Architecture of a ZigBee Network (source: Synapse Wireless)

But at the end of the day, selecting the winning solution is about selecting a technology that has an advantage in cost, simplicity, reliability, scalability and security where Bluetooth Mesh is unmatched. With a year under its belt, the Bluetooth Mesh standard has already been implemented in 65 interoperable products from various vendors where that number is expected to grow exponentially over the next few years (Figure 4). The key right now is to build an ecosystem of Bluetooth Mesh solutions as quickly as possible.

Figure 4: Qualified Bluetooth Mesh products [1]Figure 4: Qualified Bluetooth Mesh products [1]

About the Ecosystem of Solutions

A large ecosystem of solutions based on an open interoperable standard like Qualified Bluetooth Mesh is required to support any conceivable project specification from the type of signal from the controller to the LED driver (DALI, 0-10V, PWM), to different formfactors for integration into the luminaire, to supporting different type of sensors (occupancy, daylight harvesting, CO2, VOCs, noise, temperature, humidity) and functionality (people counting, asset tracking, beaconing, power metering, local vs. Cloud based system).

The benefit of the future-proofing characteristics of Qualified Bluetooth Mesh is that if the end customer is not ready to leverage the data on the Cloud that a system can generate, they don’t need to include gateways at the time of installation of the lighting control system. But having the peace of mind that if a strategic decision is made at some point to leverage the power of the Cloud, the option to do so is available with low-cost Qualified Bluetooth Mesh gateways that are currently being designed by a number of vendors. As an example, for a retail store, understanding where customers are spending most of their time during the course of the day or the holiday season may encourage them to make changes that can increase revenue. Alternatively, understanding how many people are in a conference room may adjust the HVAC system to maximize comfort or save energy.

There have been several press releases about the potential emergence of Li-Fi for retail and museums where data can be sent directly to the phone by modulating the light in the luminaire to the light sensor on the phone where the user can receive location specific messages such as product information. The challenge with Li-Fi is that it requires specialized equipment and is expensive and complex to implement. Furthermore, the Bluetooth standard already inherently supports beaconing, which provides the same functionality without the need for extra equipment at the luminaire level. Again, Bluetooth Mesh responds to the evolving needs of the market in a simple low-cost way.

Measures to push the ecosystem of solutions

There are two types of lighting OEMs in terms of lighting control. The first type is reacting to the project specification and simply including the specified control product in the luminaire without learning its features/benefits nor how to commission it. There is no commitment or investment from the lighting OEM in this case.

The second type are lighting OEMs that have made the decision to have a strategic proactive approach to lighting control. They typically select a lighting control technology and invest in at least one dedicated lighting control resource to fully understand the solution, work on developing a marketing presence and most importantly, they train their salespeople and agents on how to position the technology with end customers, specifiers and electrical distributors. As the number of lighting OEMs that convert to implementing a proactive lighting control strategy increases where they embrace an interoperable open standard like Qualified Bluetooth Mesh, it will gradually strengthen the ecosystem and its influence over specifiers to include the standard in their next project, which will further increase the rate of adoption.

About Wired Technologies as an Option for a Future- Proof Installation

In contrast to the widely discussed wireless solutions, there are also some very specific proposals that don’t leverage radio frequencies: bus systems via a controlling cable, power line carriers, or Power-over- Ethernet (PoE). Some of these approaches are promoted as more reliable than wireless systems. But we need to ask ourselves if all of these systems are truly competitive.

The wired technology that has been getting the most attention in the past few years has been PoE. Typically, for a disruptive technology to be successful, it must also embrace or bridge the existing one. In the case of lighting control, what would be difficult to fundamentally change in the short term would be the LED driver. Lighting OEMs must have flexibility in their source of LED driver options with different output power, output current, output voltage and form factor. However, with PoE, traditional LED drivers cannot be leveraged where options are still very limited for PoE compatible LED drivers. Furthermore, the PoE switches, which power the PoE LED drivers are still very expensive and limited in how much power they can provide to multiple luminaires. Finally, there is no escaping the fact that the IT department will need to be involved and supportive of a PoE system, which adds another level of complexity. Since Bluetooth was initially developed to be a very reliable wireless cable replacement, for PoE to carve a niche in the lighting control arena, it needs to provide some additional value that leverages its strengths, such as high data rates. With PoE, luminaires can also process and send audio and video data with microphones/speakers and IP cameras where lighting and security can be combined or to enhance the functionality of a video conference room.

The other wired protocol that is evolving with the needs of the market is DALI and in particular DALI 2.0. As examples, DALI 2.0 is improving interoperability of the protocol to minimize issues during installation. The upgrade also incorporates the use of occupancy and daylight harvesting. Advanced functionality such as supporting tunable white from a single DALI address is now also part of the standard. But the likely greatest impact to the lighting OEM and lighting control markets is the upcoming release of DALI driver diagnostic standard that will also include power metering. This will enable all LED driver manufacturers to leverage a common interface and protocol to develop the next generation of LED drivers.

Conclusions

An increasing number of companies are starting the process to adopt Qualified Bluetooth Mesh. The advantages the protocol will bring to the lighting industry and building automation as a whole are clear. An interoperable, low-cost, simple, reliable, scalable and secure standard that has the potential to bring unity and clarity to lighting OEMs, specifiers and building managers. Qualified Bluetooth Mesh was specifically developed to address the drawbacks of existing protocols, which had forced several new lighting control equipment vendors to create their own proprietary solutions. However, this had caused confusion in the lighting industry where many lighting OEMs have been waiting on the lighting control technology dust to settle before investing proactively. It will still take a couple of years before the Qualified Bluetooth Mesh ecosystem reaches critical mass. However, the opportunity cost for lighting OEMs to wait further may be too high as some of their competitors may already be investing before the dust fully settles. Now is the time to make the philosophical transition from “the first duck out of the pond gets shot” to “the early bird gets the worm”.

References:

[1] Source: www.bluetooth.com

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