Saturday, 19 October 2019 14:08

Home Automation Protocols for the Internet of Things

 

Home automation means, using Internet of Things (IoT) to connect and control household devices and appliances. Home Automation protocols on the other hand are the ways to communicate this information to other devices, either in a wired manner, or wirelessly. Here is a good introduction of some Home Automation Protocols that can be used to establish your next smart home.

 

While the concept is not a new one – since smart lights and timer based appliances have been around for a while now – the advent of IoT and Artificial Intelligence has given home automation a whole new dimension. These days, smart homes can be monitored and controlled remotely with minimal user oversight. Moreover, the development of parallel technologies such as smartphone apps and remote access protocols has greatly improved the usage scenarios for home automation, providing convenience, control and security to smart home users.

In another context, home automation has also resulted in cost savings and proved beneficial for the environment, by minimizing idle energy usage in residential and commercial buildings.

Home Automation Protocols in 2018

Last year, home automation technology witnessed a huge leap forward. Products like Amazon Echo and Google Home were finally able to break into the mainstream consumer space and start an industry trend. Consequently, 2019 is expected to continue this trend with technologies like facial recognition, voice commands and biometrics finding wider application in smart home solutions.

Leading tech companies are investing huge amounts in R&D to create their own connected home and office ecosystems. The ultimate vision is to create completely automated systems which can recognize and respond to select individuals or user groups, within a home or office environment.

Here we review the popular home automation protocols in use today.

  • Zigbee
  • WiFi
  • Bluetooth
  • 6LoWPAN
  • Thread
  • ANT and EnOcean
  • Comparison of Protocols

X10 Home Automation

One of the first home control technologies to be introduced, x10 has been around since 1975. X10 utilizes existing power lines for controlling lamps, appliances and monitoring doors and windows. Technically, X10 is a little behind its time, and delays between an action and reaction are perceivable due to its use of RF signals. X10 protocols are also susceptible to disruptions related to line noise and require additional installation of filters, couplers and repeaters to minimize such instances.

An upgrade called the Universal Powerline Bus (UPB) was introduced in 1999, which addresses most of the X10’s shortcomings. UPB uses a more complex setup involving unique device IDs, shared network access and individual network passwords to provide a more realistic and customizable smart home implementation.

Zigbee Home Automation

A leading name in smart home technology, the Zigbee protocol is renowned for its convenient operation and interoperability with older versions. The protocol claims to add almost seven years of battery life to smart security sensors – providing a long-term home security solution. Since it uses standardized pairing requirements, Zigbee is also compatible with most modern devices and appliances, which reduces the overall cost of development for product owners and developers.

Zigbee home automation also comes with DIY configurations, allowing greater customizability for both product engineers and end-users. Here are a few of Zigbee’s salient features –

  • Remote access with internet monitored control of a smart home.
  • Smartphone app support for modulating smart home appliances and devices.
  • Smart power management and control for supported products.
  • Supports installation of additional certified security devices and protocols for enhanced home security.
  • Allows lighting products to utilize dynamic lighting controls, often used for creating unique home and office environments.

Zigbee is one of the few smart home protocols that offer greater customization options to product planners. The company has an HA certification and compliance program to ensure that certified products seamlessly integrate with Zigbee home automation protocols.

Due to its hugely scalable nature, wireless operability and use of AES 128-bit encryption for protecting personal data, the protocol can be used for office and business environments as well.

Insteon Home Automation

Insteon domotics technology uses both power lines and radio frequency communication for smart home connectivity. The protocol requires all messages – received by a compatible device ­– to be checked for errors, and instills corrections, hence increasing the reliability of functions.

However, Insteon protocol and its supported products were subject to certain instances of whitehat hacking in the past. In multiple cases, hackers were able to access Insteon users’ smart homes and personal information. Those protocols have been retired since.

Wi-Fi Home Automation

Given the penetration of Wi-Fi networks within local area networks, it is one of the most convenient protocol to work with for home automation devs. Wi-Fi protocols provide a ready-made infrastructure with an inherent ability to manage high quantities of data. Another advantage of using Wi-Fi protocol for home and office automation is the in-built AES 256-bit encryption. However, poor Wi-Fi speed and signal strength may bottleneck performance in larger domotics setups. Additionally, most homes and businesses are using 802.11n Wi-Fi standard, which is too power consuming for most IoT applications.

The Wi-Fi Alliance recently announced a new 802.11ah standard. Termed Wi-Fi HaLow by the Alliance, the protocol can operate over greater distances than the existing 2.4Ghz and 5Ghz bands – purportedly up to 1 kilometers under ideal conditions – and has been especially developed for the implementation of IoT and automation.

Although the real-world application of this protocol still needs to be tested thoroughly, the propensity of the 900Mhz band to operate amidst various interferences is well known. The sub-gigahertz operation of Wi-Fi 802.11ah allows better smart home, connected car and digital healthcare deployment. Thus, in theory, products utilizing the HaLow band will have significantly better coverage area. Also, the HaLow band can transmit at a minimum frequency of 150Kbps over channels up to 2Ghz. This means connected IoT devices can quickly resume their passive state after waking up to receive instructions – conserving more power – and hence overcoming one of the inherent limitations of current Wi-Fi networks.

The limiting factor of HaLow band however is its transmission speeds, which remain in low tens of megabits per second and may not satisfy product planners who require higher bandwidths.

Bluetooth Home Automation

Bluetooth networks have been occasionally utilized by smart home product developers as a home automation protocol, although the existing technology remains limited by its range and signal quality. Still, certain smart home devices can use Bluetooth signals to connect and perform basic tasks (depending on the level of support).

Security Concerns: The major concern for product owners using Bluetooth networks for home automation is of security. The existing Bluetooth Low Energy (LE) technology is prone to sabotage due to multiple security exploits, such as,

  • Passive eavesdropping, which allows a third device to intercept data exchanged between two paired devices. While BLE uses AES 128bit encryption to secure the data transfers, there are still some protocol deficiencies which can be exploited by hackers to intercept and decrypt personal data.

  • Man-in-the-middle or MITM attacks, which allow a third-party device to insert itself between two legitimate devices, giving them the illusion that they are interconnected. The interception allows the malicious device to fool Gap Central and Gap Peripheral and tamper with the information being exchanged.

  • Identity tracking, where a third party is able to track a specific user by associating a BLE device address with his device. In this instance, BLE does have a mechanism to periodically alter the device address to overcome this shortcoming.

Bluetooth 5 and Bluetooth Mesh: The upcoming launch of Bluetooth 5 and Mesh technology represents the biggest improvement in the Bluetooth technology since its launch. Bluetooth Mesh will transform the current technology from being a point-to-point, star-based network topology to a true mesh networking topology. This will extend the range of supported Bluetooth devices beyond the typically personal area networks we have today. Furthermore, mesh will allow expansion of Bluetooth coverage through additional nodes, opening up opportunities for smart home products which are not tied down to internet connectivity. The newer Bluetooth standards will also use newer encryption and security measures to overcome the existing security flaws.

6LoWPAN Home Automation 

The acronym is a combination of the latest version of IPv6 protocol and Low-power Wireless Personal Area Networks (LoWPAN). 6LoWPAN can transmit information wirelessly using an internet protocol and is especially meant for connecting the smallest of the devices with IoT.

6LoWPAN’s machine to machine and IoT Applications include:

  • 6LowPan Smart Meters

  • Smart Home Appliances (Lighting, Thermostats, etc.), and

  • All low power units which can work in proximity to a neighboring transceiver.

Thread Protocol for IoT

Proposed first by Google, Thread is an open set of protocols for smart home solutions. Thread operates wirelessly using IP address protocols, just like 6LoWPAN, and means to connect even more low powered devices within a home automation setup. Thread uses a number of modifications and features to iron out the existing bottlenecks in home integration through,

  • An Open Standard Protocol carrying IPv6 packets over 6LoWPAN.

  • Simplified user interface and support for both smartphones and computers for managing domotics.

  • A secured and AES encrypted network to minimize data breach.

  • Seeping very less power from connected devices – prolonging battery life of connected sensors.

  • Independent node activation, meaning there is no single point of failure for devices in the mesh.

  • Universal support for a variety of devices and home appliances.

ANT Home Automation

Marketed by ANT Wireless, this is a home automation system which uses a wireless communications protocol stack. ANT enables hardware operating in the 2.4GHz ISM band to communicate through rules for co-operation.

ANT nodes can concurrently act as slaves or masters within a wireless sensor network. Meaning, the nodes can act as transmitters, receivers, or transceivers for routing traffic to other nodes. Also, the nodes can automatically decide the time of transmission based on the activity of nearby nodes.

EnOcean Home Automation

The technology is used for building automation systems that rely on the energy harvesting wireless technology. EnOcean modules are a combination of ultra-low power electronics and energy converters, enabling communication between sensors, switches/controllers and gateways without battery power.

EnOcean offers licenses for its patented features within the closed EnOcean Alliance framework and has found many other applications (in transportation and logistics) besides home automation.

The Best Protocols for Home Automation

Among the listed home automation methods Zigbee, 6LoWPAN, Thread and Bluetooth LE offer the most promising results for IoT driven home automation. Where Zigbee and 6LoWPAN are widely used due to their ease of installation and interoperability – Bluetooth and Thread promise better integration in the near future. Here is how product managers and developers can benefit from integrating these protocols in their smart home solutions,

  • Zigbee: Allows a large number of product customizations and scalability. The integration and certification process is easy, and Zigbee also allows backward compatibility for older products. Additionally, the protocol has in-built security measures, eliminating the need for additional steps from product developers.

  • 6LoWPAN: Ideal for battery powered sensors such as temperature, smoke etc. and controlling household appliances such as washing machines. The ultra-low energy usage of this technology has made it one of the best smart home technologies.

  • Bluetooth: While not so utilizable in its current form, Bluetooth home automation will find widespread usage once the mesh functionality is released. Product planners will be able to develop and deploy smart home solutions with independent and interdependent operation within local private networks.

  • Thread: The initiative is backed by a wide number of hardware and software vendors for joint smart home development. Its universal adoption means faster framework updates, better security and lower energy usage for smart home developers.

Home Automation Protocols ­– Comparison

 

Variable

Wi-Fi

Z-Wave

Zigbee

Thread

BLE

Area Coverage

Wide

Wide

Wide

Wide

Wide*

Power Efficient

No

Yes

Yes

Yes

Yes

Data Bandwidth

High

Low

Low

Low

High*

Frequency Band

2.4GHz

900MHz

2.4GHz

2.4GHz

2.4GHz

Topology

Star

Mesh

Mesh

Mesh

Scatternet

Alliance

Wi-Fi Alliance

Z-Wave Alliance

Zigbee Alliance

Thread Group

Bluetooth SIG

 

While Wi-Fi has been the de facto standard for WLANs, its use as home automation protocol remains marred by low power efficiency. On the other hand, Z-wave, Zigbee and Thread are offering lower data bandwidths which are ideal only for ultra-low power operation and maintaining longer battery life of sensors. It is Bluetooth LE that can offer both higher data speeds and low power consumption (under ideal conditions), but again falls short on security.

Concluding thoughts

Automation remains a primary focus area in almost all fields today, and most IoT technologies are focused on enhancing M2M control over manual tasks. Smart homes form a significant part of that plan, offering smart product owners and smart home developers a window of opportunity to adapt and evolve as early as they can.

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Saturday, 19 October 2019 13:05

LoRaWAN - Explained

Beginning in the early 1990s connecting to the internet began as a simple direct path. Nowadays things have advanced and have become more complex but also more capable. Instead of a single Ethernet connection to the internet, microcontrollers and other devices can connect through a long list of protocols: Bluetooth, WiFi, BLE, ZigBee, 3G, 4G, 5G, NFC, RFID, SigFox, DigiMesh, Thread, and 6LoWPAN to name a few. Each of these connections plays a valuable role for device connection and data transmission, but one budding protocol we would like to highlight is LoRaWan.

Like those listed above, LoRaWAN is a wireless connection network for data communication to the internet. LoRaWan is quickly set itself apart as it becomes known and tailored to IoT (Internet of Things) applications that require long-range and low-power connectivity to the internet without WiFi. LoRaWan is a great answer for remote battery-powered sensors or devices that communicate over long distances or in remote places. LoRaWan said simply, packages data are sent, when needed, over long distances to the nearest, most available gateway which forwards said packets of data to the server for storage, computation, or visualization.

To become more familiar with LoRaWAN, let’s got back to 2009 when the precursor to LoRaWAN called LPWAN began in France:

  • LPWAN is a wireless telecommunication wide area network designed to allow long-range communications at a low bit rate for things (connected objects), such as sensors operating on battery with low power requirements.
  • LPWAN enables connectivity for networks of devices that require less bandwidth than what the standard home equipment provides
  • LPWAN networks also support more devices over a larger coverage area than consumer mobile technologies and have better bi-directionality capabilities
  • Networks like WiFi and Bluetooth are more adequate for consumer-level IoT applications, however, LPWAN is more abundant in industrial IoT, civic and commercial applications

LPWAN is the cumulative network that encompasses LoRaWAN. Hence, the two are not synonymous, but instead two separate networks. LPWAN came first and then adopted under it several networks that each had their unique historical upbringing. Some of these adopted networks include AlarmNet (which was later taken under ownership by Honeywell), the 2G network, and LoRaWAN, which was created by a group called the LoRa alliance in 2014 and is amongst the leading and favorite protocols for connected devices.

How LoRaWAN Works:

NOTE: A list of common terms and definitions have been included at the end of this post as a Glossary.

Using the infographic above, sensor connecting to the internet is referred to as end–devices. Whenever the sensor takes a reading the device conditionally sends a signal (data packet) that the gateways to capture the data. Now that data at the gateway uses FSK (Frequency Shift Keying) to transmit that data as efficiently as possible to the server using a process called the Chirp Spread Spectrum (CSS). As the data packet from the end device enters the circuitry of the gateway, it comes in “chirps,” or symbols that represent digital information (like below). The chirp is then parsed down to the frequency domain and then a modulated signal to efficient data transport.

 

The LoRa hardware, after converting the input signal to the frequency domain, is searching within the frequency band for other,better frequency channels that can carry the signal. Once the gateway finds one, this whole process modulates the input signal’s frequency to make it more energy efficient, and then “shifts” (hence the “S” in FSK) the signal to that channel for quick data transmission.

The end-devices and gateways continuously interact with each other so that the data transmission can “hop” to other frequency channels that best suits the system’s power, speed, duty cycle, and range restraints.

During this frequency modulation, other integrated circuits within the LoRa gateway performs other “improvement” modulations, like filtering out noise, or the jaggedness that you see in a signal.

 

Another reason why LoRaWAN is a low-power, long-range network is thanks to a process called ADR (Adaptive Data Rate). Just like how the FSK process “shifts” the input signal frequency to boost efficiency, ADR “talks” to the LoRaWAN network server to boost the data rate. This is how the “talking” is done between device and server:

  1. The end-devices (nodes) constantly send uplink messages to the network server of LoRaWAN. These uplink messages are comprised of lots of information about the node’s past 20 signals
  2. The network server analyzes the recent history of the node and makes comparisons to see how much “margin” there is to make changes
  3. The network may observe that there is a “margin” for sacrificing range for something more useful, like a faster data rate. (Notice from the diagram that the trash can is sending its data to more gateways than any of the other devices)
  4. Instead of sending slower messages to far away gateways, the server would rather have the end device send a quick message to one gateway nearby.
  5. Hence, the ADR process takes advantage of opportunities that will boost the data rate. If the sacrifices being made helps the system operate more efficiently, then the sacrifice will be made using ADR.

After the gateways receive and interpret a data packet using LoRa technology, the gateway forwards the data to the network server via standard IP connections, like Ethernet or 3G. If the network server receives the same data packet from several gateways, it will only process one of them, and disregard the copies. Hence, if the server will receive three of the same data packet because the trash can is connected to three gateways in our illustration, then only one of these data packets will be processed, making for a highly accurate and very efficient data transfer.

Tradeoffs

As in every engineering application, there are trade-offs in the world of LoRaWAN when it comes to power, speed, and range. This simple diagram below displays the points of consideration.

 

Increasing time of data bit ——-> reduces data rate ——-> lower speed
Decreasing time of data bit ——-> increases data rate ——-> higher speed
Increasing the range and reducing power ——-> lower speed
Increasing the range and quickening the speed ——–> requires higher power
Increasing the speed and reducing power——-> shorter range

Frequency Bands

LoRaWAN uses lower radio frequencies at a longer range, and the frequency bands differ between countries.

  • Europe: 863-870 MHz and 433 MHz bands (868 MHz used by The Things Network). Three common 125 kHz channels for the 868 MHz band (868.10, 868.30 and 868.50 MHz) must be supported by all devices and networks.
  • USA: 902-928 MHz band, divided into 8 subbands. Each of these subbands has eight 125 kHz uplink channels, one 500 kHz uplink channel and one 500 kHz downlink channel. As opposed to Europe’s frequency channels, those of USA are classified as uplink and downlink channels
  • Australia: 915-928 MHz band. Uplink frequencies in Australia are on higher frequencies than in the US band. However, the downlink frequencies are the same as in the US band.
  • China: 779-787 MHz band, with three common 125 kHz channels (779.5, 779.7 and 779.9 MHz), and also there exists a 470-510 MHz band, with 96 uplink channels and 48 downlink channels

Classes

LoRaWAN categorizes its end-devices in three different classes to address the different needs reflected in the wide range of applications.

Class A:

  • these devices support bi-directional communication between a device and a gateway
  • lowest power category
  • Class A devices function only in applications where they send an uplink transmission and wait for downlink communication from the server shortly after
  • uplink messages can be sent at any time
  • after sending an uplink message, Class A devices open two receive windows at specified times
  • the server can respond in either window
  • the transmission slot (time slot) scheduled for each window by the end-device is based on its own communication needs
  • if the server does not respond in either of these two receive windows, the next opportunity will be after the next uplink transmission

The first line in the diagram is the chronological process of the class A end-device uplink/downlink process. First, it is sends an uplink signal, waits, then opens up the first receive window; waits again, then opens up a second receive window. The next two lines demonstrate successful reception of a downlink signal after the downlink signals are captured by the receive window. The last line demonstrates unsuccessful reception of a downlink signal because it is not captured by the end-device in either receive window.

Class B:

  • Class B end-devices are bi-directional with scheduled receive slots, like Class A
  • The difference: Class B devices open extra receive windows at scheduled times in addition to Class A’s receive windows
  • Unlike Class A devices, which open their receive windows based on their own communication needs, Class B devices receive a time synchronized beacon from the gateway, allowing the server to know when the end-device is “listening”

Class C:

  • Class C devices are bi-directional with maximal receive slots
  • These devices almost have continuously open receive windows, which are only closed when transmitting
  • This allows for low-latency communication but is many times more energy consuming than devices in Class

Over-The-Air-Activation (OTAA)

To participate in a LoRaWAN network, each end-device has to be personalized and activated. The functionality of this process is summarized in these steps:

  1. For over-the-air activation, end-devices must follow a join procedure prior to participating in data exchanges with the network server.
  2. The join procedure requires the end-device to be personalized with the following information before it starts the join procedure: a globally unique end-device identifier (DevEUI), the application identifier (AppEUI), and an AES-128 key (AppKey).
  3. The join procedure consists of two MAC (media access control) messages exchanged with the server, namely a join request and a join accept.
  4. The end-device sends the join-request message consisting of AppEUI and DevEUI of the end-device followed by the DevNonce.
  5. The join-request message can be transmitted using any data rate and following an efficient frequency hopping sequence across the specified join channels.
  6. The network server will respond to the join-request message with a join-accept message if the end-device is permitted to join a network.
  7. After activation, the following information is stored in the end-device: a device address (DevAddr), an application identifier (AppEUI), a network session key (NwkSKey), and an application session key (AppSKey).

If step 7 is successful, OTAA is accomplished.

Activation by Personalization (ABP)

Under certain circumstances, end-devices can be activated by personalization. Activation by personalization directly ties an end-device to a specific network, by-passing the join request – join accept procedure. So, opposite to that of OTAA, the DevAddr and the two session keys NwkSKey and AppSKey are directly stored into the end-device instead of the DevEUI, AppEUI and the AppKey. Simply, the end-device is already equipped with the required information for participating in a specific LoRa network when started.

The advantage of ABP is that it is easy to connect to the network because the device can be made operational in little time, which is very suitable for certain applications. The disadvantage is that the encryption keys enabling communication with the network are pre-configured in the device, which weakens security.

Conclusion

To summarize, the key points of LoRaWan:

  • LoRaWAN covers long distances, making it ideal for both urban and rural solutions
  • LoRaWAN consumes less power which makes the technology ideal for battery powered devices
  • LoRaWAN provides low bandwidth communication which makes it the ideal solution for practical IoT deployments that require less data
  • Relatively low deployment costs compared to mobile or WiFi due to the lower number of Gateway devices required
  • LoRaWAN supports bi-directional communication
  • A single LoRaWAN Gateway can accommodate 1,000s of devices or nodes, multiple Gateways provide resilience to smart solutions

Glossary of Terms

Refer to this section for definitions of technical terms to aid you in understanding LoRaWAN. For your convenience, these words will be bolded in the tutorial when used.

Adaptive data rate (ADR): mechanism for optimizing data rates, airtime and energy consumption in the network

AppEUI:is a global application ID that addresses space and uniquely identifies the application provider (owner) of the end-device.

AppKey: an AES-128 application key specific for the end-device that is assigned by the application owner. The AppKey is used to derive the session keys NwkSKey and AppSKey specific for that end-device to encrypt and verify network communication and application data.

AppSKey: is used by both the network server and the end-device to encrypt and decrypt the payload field of application-specific data messages

Band: a range of frequencies with a specific least frequency and greatest frequency

Bandwidth: measures how much data can be sent over a specific connection in a given amount of time (synonymous with data rate)

Chirp Spread Spectrum: a type of modulation technology that is responsible for the reliability of the transmission as well as low power consumption

Cloud: a platform designed to store and process IoT data. The platform is built to process massive volumes of data generated by devices, sensors, websites, applications, customers and partners and initiate actions for real-time responses.

Data rate: the amount of digital data that is moved from one place to another in a given time; can be viewed as the speed of travel of a given amount of data from one place to another, based on how wide the bandwidth is

DevAddr:contains a network identifier (NwkID) to separate addresses of territorially overlapping networks of different network operators and to remedy roaming issues. It also contains a network address (NwkAddr) of the end-device.

DevEUI: a global end-device ID address space that uniquely identifies the end-device

DevNonce: a random value associated with an end-device. If an end-device tries connecting to the server with a DevNonce value that it has already previously used before, the server will ignore the request, preventing a system catastrophe known as replay attacks

Downlink: the link (connection) from a satellite to a ground station. Frequency of downlink signals tend to be broader to cover a large area on earth and provide as many services as possible

Duty Cycle: the percentage of the ratio of pulse duration, or pulse width (PW) to the total period (T) of the waveform. Duty Cycle = PW/T * 100%

Here’s a diagram to help you better visualize what a duty cycle is:

End-device/Node/End-point: an Internet-capable computer hardware device. The term can refer to desktop computers, laptops, smart phones, tablets, thin clients, printers, or literally any object that can connect to the internet

Frequency channel: when a band is channelized, that means there are specific discrete frequencies that a device (like a radio) will use and transmit data on. Instead of arbitrarily choosing random frequencies to use within the band, a device or network will stick to a certain step size to boost efficiency and avoid wasting gaps between different frequencies. For example, for a band 28-29 MHz, 3 different 100KHz channels could be 28.1 MHz, 28.2 MHz, 28.3 MHz, etc

Front-end: users (like a human being, or a program) interact with the application directly

LoRa: a proprietary, chirp spread spectrum (CSS) radio modulation technology for LPWAN used by LoRaWAN. LoRa is the physical layer, LoRaWAN is the network

LoRaWAN(Long Range Wide Area Network): a media access control (MAC) layer protocol for managing communication between LPWAN gateways and end-node devices, maintained by the LoRa Alliance

LPWAN(Low-Power Wide Area Network): a wireless wide area network technology that is specialized for interconnecting devices with low-bandwidth connectivity, focusing on range and power efficiency

NwkSKey:is used by both the network server and the end-device to calculate and verify the MIC (message integrity code) of all data messages to ensure data integrity.

Throughput: a measure of how many units of information a system can process in a given amount of time

Uplink: the link (connection) from a ground station up to a satellite. In IoT applications, signals must cross the atmosphere where attenuation is inevitable (from rain, for example). To avoid as much attenuation as possible, stations on earth boost their uplink signals with more power so that the frequency is narrower (so the signal could “fit” through obstructions in the environment). Hence, uplink signals generally have higher frequencies than downlink signals.

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