Most buildings, primarily residential, are not wired to connect their existing systems, such as HVACs, elevators, security cameras, and other devices. Wireless IoT devices using technologies such as LoRaWAN or NB-IoT can help connect new devices and sensors and retrofit existing ones.
Connecting new sensors and control systems to existing assets is challenging. In most cases, every appliance, elevator, HVAC, and security system came with its own connectivity, if any.
Over the last three decades, many building owners have been wiring their installations to enable the possibility of managing those systems remotely, from a control room, or several control panels. While this approach allows for real-time information about the current conditions of different building systems, it falls short in collecting precious data about the operating status, component wear, environmental conditions, etc.
To take advantage of analytics and automation, infrastructures must be fitted with sensors and other intelligent devices and connected with consolidated control systems.
When designing a new building, it is essential to decide what kind of connectivity is needed. While most new facilities are ready for wired connections, it’s a good idea to consider cellular and other wireless networks to enable different types of devices, especially battery-powered sensors.
Furthermore, wireless connectivity could be the best solution for connecting different types of systems in older buildings, as the effort to wire the infrastructure could be messy, costly, and unable to reach all areas of the edifice.
New Cellular Technologies Specifically Designed for IoT
The rapid increase in the number of IoT devices, and the power requirements to connect billions of them, makes it necessary to consider low-power communication technologies.
Until the arrival of long-term evolution (LTE), commonly referred to as 4G, most wireless connected devices used Wi-Fi or 2G cellular networks to send and receive data. Even today, some devices, mainly security cameras and monitoring systems, still use 2G–widely available in most regions worldwide.
Ten years ago, 4G started a change. The new cellular standard was the first to leverage data communications over traditional voice and text. Furthermore, the different releases of 4G enabled additional features such as carrier aggregation and low-power communication.
The explosion of new IoT devices, especially sensors for industrial and building applications, required new cellular features such as low-power, wide-area connectivity, and easy onboarding of new devices.
The first part, low-power connectivity, arrived in 2016 with two new 4G standards that carriers could install in existing networks: LTE Machine Type Communication (LTE-M) and Narrow-Band IoT (NB-IoT). Both were defined in the 3GPP Release 13, which became standard in June 2016.
LTE-M and NB-IoT work by using small bursts of data over 4G networks. The advantage of LTE-M over NB-IoT is its comparatively higher data rate, mobility, and voice over the network. Still, LTE-M requires more bandwidth and is more costly for device manufacturers. NB-IoT offers lower power consumption and cheaper modems but doesn’t support voice or SMS.
Operators prefer LTE-M because it only requires a software update on their networks. However, device manufacturers who don’t need SMS or voice prefer NB-IoT due to its lower power usage and cheaper modems.
LTE-M is prevalent in North America, but operators now also offer NB-IoT connectivity.
The second challenge, the easy onboarding of new devices, is achieved using an embedded Subscriber Identity Module (eSIM). Until the arrival of the GSMA eSIM specification, every device connected to a cellular network needed a hole and a slot for a plastic SIM module, the same that is present in all smartphones.
eSIMs, as small as a pinhead, and integrated SIMs (iSIMs), embedded in other chips, allow device manufacturers to design small devices, and operators can, after installation, supply those over-the-air (OTA) with the cellular carrier credentials. No manual intervention is required.
The main advantages of using cellular connectivity for smart devices are the availability of cellular networks and better security. Today, thousands of cellular networks operate worldwide using the same standards, and the communications are encrypted using hardware-based security, the SIM modules. However, the main disadvantages are high power consumption compared to other LPWANs and cost—both on the device and the usage fees paid to the cellular providers.
Non-Cellular LPWANs Reduce Cost and Power Consumption
Probably the most common wireless connectivity present in a building is Wi-Fi. The ubiquitous presence of this wireless standard makes it ideal for connecting the many devices that come featuring a Wi-Fi modem. Thermostats, security cameras, air conditioners, and many other smart devices could connect easily to a Wi-Fi access point.
Connecting everything by Wi-Fi, however, poses some challenges and inconveniences. The Wi-Fi range is severely limited, and signals are blocked by walls, floors, and other objects. To ensure good communication between the network and devices, it is necessary to install many access points in the building.
Secondly, Wi-Fi is power hungry. Not only do the routers, switches, and access points need to be plugged in, but so do the hundreds of devices connected to the network. While this is not a problem with large devices, it is an issue for small sensors and other battery-powered units.
New Low-Power Wide-Area Network (LPWAN) standards have appeared in the market in the past few years. These standards are specifically designed to connect low-power devices, mostly running on batteries, to gateways using sub-GHz unlicensed spectrum. Probably the most popular and installed is LoRa. Other examples include Zigbee and Sigfox.
LPWANs such as LoRaWAN can solve the two main problems using Wi-Fi. The range expands significantly by using a sub-GHz unlicensed spectrum. In many cases, a single LoRa gateway can serve an entire building. Additionally, the low power consumption and limited bandwidth—LoRaWAN bandwidth ranges from 0.3 kbps to 50 kbps—allow for using battery-powered devices that require only limited connectivity, meaning that a small sensor could operate for several years without maintenance.
Furthermore, the worldwide LoRaWAN network makes it unnecessary to install on-site gateways. Like cellular connectivity, LoRaWAN can connect thousands of IoT devices with less power consumption at a fraction of the cost.
Security over LoRaWan uses standardized AES-128 cryptographic algorithms. The keys can be pre-installed at the production line, during commissioning, or Over-the-Air Activated (OTAA) in the field. OTAA allows devices to be re-keyed if necessary.
No Network Fits All
Undoubtedly, different systems, components, and devices for smart buildings need different types of connectivity.
Sensors monitoring environmental conditions and the health of appliances and other systems only require sending and receiving small data bursts. They are better served by an LPWAN such as LoRa, reducing the power consumption and cost.
Security systems such as cameras, motion detectors, and other real-time applications require more bandwidth and stable connections, which cellular and wired connectivity can provide.
Other devices, such as thermostats and smart windows, can efficiently operate on Wi-Fi access points or connect by wire.
Interoperability Is Key
The biggest challenge for building designers and developers is making all the different devices work together. Until now, most solutions for buildings are based on independent silos—partial solutions addressing only one section or part of an infrastructure.
That’s why new platforms are now appearing in the market, allowing different systems and networks to work together. One is Building X by Siemens, which is not limited to using Siemens’ hardware. Vendors and other building management companies can integrate their existing systems into the platform, reducing the initial investment and additional costs. This way, they can have a single pane of glass, or a digital twin, to manage their buildings efficiently.
Microsoft is also entering this growing market through IoT Central and Azure Digital Twins. “We are joining forces with other industry leaders to accelerate the use of Digital Twins across vertical markets,” says Sam George, Corporate Vice President of Azure IoT at Microsoft. “We are committed to building an open community to promote best practices and interoperability, to help establish proven, ready-to-use design patterns, and standard models for specific businesses and domain-spanning core concepts.”
