Commissioning of Connected Lighting Networks – What Makes it so Challenging?
With constant technology advancements and growing market awareness, we are all getting more and more familiar with various aspects of wireless lighting controls. However, the commissioning process still seems not to be getting the attention it deserves. Let’s break it down into pieces, while looking at how the Bluetooth mesh standard addresses major commissioning challenges.
Commissioning is said to be one of the more difficult issues for developers of connected lighting systems. This is partly due to the technical complexity of wireless lighting control technologies in general, but also due to multiple limitations that different wireless protocols impose in this regard.
To understand what wireless commissioning is all about, you need to forget everything you know about commissioning of traditional, wired systems. In the world of wireless lighting controls, this is just a completely different procedure that requires a new mindset and new tools. Regardless of the wireless technology used, the commissioning process can be broken down into three major stages: network formation, device identification/mapping, and logic configuration.
Smart lighting installations are, at their core, nothing but IT networks. Therefore, the network formation process is a typical IT procedure. And while it might not seem like a particularly challenging task, it does get tricky when you’re commissioning a 10-storey office building with thousands of network nodes, including luminaires, sensors, switches, gateways, etc. The process is also sensitive from the point of view of network security. Many – if not majority – of security flaws identified in connected lighting solutions relate to the onboarding. This is because letting an unknown device into a network is a potentially vulnerable operation. When joining the network, such device learns the network’s security keys so appropriate authentication measures need to be deployed to prevent these keys from leaking outside. What is crucial is the secure delivery of these keys. Effective authentication mechanisms also prevent potential intruders or Trojan horses from sneaking into the system when a new device joins the network.
The network formation is the part which is often completely ignored in marketing materials of smart solutions’ suppliers, or during presentations given at lighting industry events. But don’t be fooled – wireless commissioning doesn’t start with locating the right luminaires and setting up relevant interactions. The network must be formed first, and it’s a time consuming process that requires IT engineering expertise and therefore generates significant costs.
Device identification and mapping
Once a wireless network is formed, all its nodes need to be physically identified and mapped on a floor plan. Only then is it possible to set up desired interactions and scenarios. The problem is that when communication happens via a gateway – which is the case for almost all of the wireless technologies used in connected lighting systems – the commissioning device is isolated from the network in a sense that it’s impossible to tell how far individual nodes are located from it. So if you’re commissioning a network in a multi-storey office building, you can’t even tell which nodes displayed in your smartphone app are located on the floor that you’re currently trying to set up. Developers are trying to solve this issue by implementing all sorts of experimental solutions, although there is always a price to pay in the end. At one of the recent industry conference, we even saw prototype drivers integrated with barometric sensors only for commissioning purpose. They allow for determining precise altitude of an installed driver, so that the person responsible for commissioning can at least say on which floor a particular device is located. Then, the precise location of a given luminaire can be determined (and marked on a floor plan) by forcing that luminaire e.g. to blink during the commissioning process. This solves the identification/mapping issue to some degree, although the question is whether barometric sensors is what we really need inside our luminaires.
Once the network has been formed and all its nodes have been identified and mapped, the logic configuration of the entire installation must be set up. This means specifying all the interactions between all devices within a network. Relevant switches must be assigned to appropriate luminaires, the sensory infrastructure needs to be configured to trigger desired events and scenarios appropriately, and all operational parameters must be adjusted so that the system operates as desired (or as required by building energy codes). This is, again, a time-consuming procedure that requires dedicated software tools. The design of these tools is going to have a profound impact on how user-friendly the commissioning procedure is, how long it lasts and how much it costs.
Putting the pieces together
These three major stages of the wireless commissioning process are very different from each other. In a vast majority of cases, you will need dedicated software tools, and dedicated competences, for each of them. When a network needs to be reconfigured for whatever reason, relevant actions will need to be carried out within each of the above mentioned areas. This obviously generates additional commissioning and maintenance costs. Furthermore, connected lighting systems based on the so-called patchwork wireless frameworks have even more challenges to deal with. Since they use completely different wireless technologies to handle the network/transport layers (i.e. typical networking tasks) and the application layer (i.e. logic configuration), it might be very difficult to coordinate certain issues that come up at points where these technologies directly meet with each other. Software tools used by each of them are not going to cooperate in any way, so even deeper specialist intervention might be required, and even higher costs might have to be borne.
Considering how complex the entire process is, it shouldn’t be surprising that suppliers often prefer to steer away from this subject when talking about their solutions. The history of connected lighting is simply too short, and there is still too few real-life implementations and too many different underlying technologies – with their own bottlenecks and restrictions – to say which approach is the right one. Just like the entire smart lighting environment, the wireless commissioning experience is likely to vary strongly between different systems and technologies. Let’s take a look how Bluetooth mesh networking, a new globally interoperable wireless standard which was adopted last year, handles the challenges of commissioning a connected lighting infrastructure.
Commissioning Bluetooth mesh networks
In Bluetooth mesh networking, commissioning still remains a process that involves the same three major phases: network formation, device identification/mapping, and logic configuration. In a wireless environment, there is no escape from this pattern. But at each of these stages, it provides smart solutions to some big challenges, while effectively streamlining the process.
It starts with the network formation. Since the Bluetooth radio can be found in any smartphone/tablet on the market, such devices can be used as network provisioners as long as a relevant app has been installed that reliably and securely supports all the required processes. A provisioner is a node that is capable of adding new devices to the network. An unprovisioned device cannot send or receive any network messages. But the Bluetooth radio allows it to advertise its presence to a provisioner. The provisioner (smartphone/tablet) can invite such device into a network, and once it is authenticated, security keys can be exchanged. This is when a device becomes a full-fledged network node.
What’s important, from the perspective of both network formation and other stages of commissioning, no gateway is needed to connect with individual nodes and set up the entire mesh network. Bluetooth is the only radio technology that allows for forming the network without touching the building’s core IT infrastructure. The process doesn’t require any gateways or Internet connection, so there is no need to obtain any formal agreements from the IT department – a process that can literally take months in the case of more sensitive buildings, such as banks or hospitals.
When it comes to device identification and mapping, communication with no gateway in-between also generates significant advantages. Since a smartphone can connect with any other node directly, Bluetooth’s RSSI capability (Received Signal Strength Indication) effectively solves the problem of device identification. Simply put, when your smartphone is communicating with a particular network node, it can tell how far this node is. In practice, a smartphone app can use the RSSI filter to narrow down the list of displayed luminaires and sensors to those that are located in your immediate vicinity. No barometric sensors involved.
Moving to logic configuration, Bluetooth mesh introduces a revolutionary approach that the connected lighting industry has not experienced thus far. It is called Information-Centric Networking (ICN). This concept was initially presented as an approach to evolve the Internet infrastructure and support its dynamic growth by introducing uniquely named data as a core Internet principle. Moving away from a host-centric paradigm, the ICN model doesn’t care about senders, recipients, addresses. Instead, named information is its focal point, making data independent from location, application and storage. With Bluetooth mesh, the ICN concept makes its way to the lighting industry. This is realized through a fully decentralized architecture with no single points of failure, as well as the innovative publish-subscribe communication architecture.
The host-centric paradigm is the approach that has been used in all connected lighting solutions so far. And it didn’t prove efficient enough. With all the conflicting requirements of the connected lighting environment, we’ve seen low-power, low-bandwidth communication technologies being unable to deliver wire-like reliability and responsiveness in large-scale installations. With its publish-subscribe paradigm, Bluetooth mesh moves away from a host-centric framework, enabling efficient multicast and peer-to-peer communications. Data generated by intelligent sensors becomes addressable information. Since addresses of individual nodes don’t matter, sensor data is the focal point – other nodes subscribe to it and respond accordingly. Just like in the case of the ICN-based approach to the Internet infrastructure, this generates multiple benefits. They include improved spectral efficiency, better robustness and full scalability. This is what makes Bluetooth mesh capable of handling even dense connected lighting networks found in commercial buildings. But it also radically simplifies maintenance.
In practice, the ICN approach means that during the final stage of the commissioning process, addresses are assigned to information, not to specific devices. So occupancy status for a particular room has its own address. The ambient light level in that room has an address, too. And it doesn’t matter how many sensors contribute to that. Luminaires are subscribed to these addresses, not to individual sensor devices. This solves a number of issues, one of them being device replacement. If a luminaire requires replacement, the new one only needs to be re-subscribed the same way as the previous one. There is no need to change anything in the configuration of sensors interacting with the replaced luminaire.
In Bluetooth mesh networking, the logic configuration stage can also be carried out using a smartphone or a tablet with a dedicated app.Such app can provide provisioned network nodes with necessary application keys, while also assigning publish and subscribe addresses. This allows them to communicate with other nodes of a mesh lighting network. Finally, a smartphone app can also be used to configure groups and scenes, and adjust any operational settings.
Commissioning made easy?
Last but not least, Bluetooth compacts these three major commissioning stages into a single, streamlined and time-efficient process. The Bluetooth radio covers all of the layers of the OSI communication model, which makes it capable of dealing – on its own – with all relevant processes both at the networking/transport level and at the application layer. There is no need for multiple different software tools and different experts performing individual stages of commissioning. With Bluetooth, this all can be done as part of one smooth procedure. In practice, it can look as follows:
With the first wave of Bluetooth mesh enabled devices already on its way to the market, we’ll soon be able to verify whether the wireless commissioning process can indeed be so intuitive and easy. Much still depends on the design and capabilities of dedicated software tools intended for commissioning, but the Bluetooth mesh technology itselfs provides a solid backbone for redefining the wireless commissioning experience.
Blog post prepared by Silvair.
Silvairprovides complete and flexible lighting control solutions based on the global Bluetooth mesh networking standard. The company offers full-stack firmware packages that enable a wide range of lighting control functionalities, including advanced lighting control strategies. Component manufacturers can easily integrate them into their LED and sensor products, flexibly choosing specific features in accordance with customers’ needs. In addition, Silvair provides a smart lighting platform with dedicated tools for commissioning and managing connected lighting systems in commercial spaces. www.silvair.com
To learn more: https://www.silvair.com/en/resources/tale-five-protocols/