How to Choose the Right Communication Protocol for a Building Automation System

Modern smart homes are made up of entire ecosystems of smart devices, which control everything from utilities like lighting and climate to home security and distributed audio systems. These types of smart home solutions are expected to generate over $2 billion in revenue by 2026. As smart devices are being adopted faster than ever into commercial and residential buildings, both property owners and embedded development companies are searching for optimal ways to control and connect them. 

At the moment, there are several short-range communication protocols available on the market, and each comes with its own specific perks. Some protocols have higher data transmission rates, some offer a longer connection range, stricter security measures, and an interference-free frequency channel for a premium price. Others can connect over 60,000 devices into a homogeneous system. 

This article compares the most popular wireless building automation protocols to help smart device developers choose the best option for their needs. 

Common Communication Protocols

Bluetooth

Originally developed by Ericsson in the 1990s, Bluetooth is a wireless technology that facilitates data exchange over short distances. Nowadays this technology is controlled by the Bluetooth Special Interest Group (SIG). Bluetooth operates on 2.4 GHz radio frequency, which is common among IoT communication protocols. 

What makes Bluetooth attractive to smart home owners is that they can control all their connected devices directly via their smartphones, although a gateway is required to transmit data to the Internet. In the case of Bluetooth, an ordinary smartphone can serve as a gateway.

The latest version, Bluetooth 5, was released in 2016. According to the manufacturer, it offers twice the speed and four times the range of its predecessor. 

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Introduced back in 2010, Bluetooth Low Energy (BLE) is a technology dedicated to IoT applications. It offers low power consumption, free access to official documentation, and is available on most smartphones on the market. It transfers small amounts of data in bursts. It is worth mentioning here      that a classic Bluetooth device can’t communicate with a BLE device unless both devices implement both protocols. It also has a significantly lower bandwidth compared to classic Bluetooth.

This article will mainly focus on BLE, as this is the Bluetooth generally used in smart homes.

Advantages: 

  • Manufacturers can develop compatible devices without entering any alliances and paying fees, which means users can purchase IoT devices from different vendors
  • Smart home owners can control their connected building directly with a smartphone 
  • High data transmission rate 
  • Low costs due to hardware simplicity 
  • Its client-server model requires less engineering and development time
  • Easy internet access through a smartphone

Disadvantages:

  • Limited number of connected devices
  • Operates over the crowded 2.4 GHz frequency 

ZigBee

ZigBee is a building automation protocol based on the IEEE’s 802.15.4 standard. It was designed to transmit small amounts of data over moderate distances. Despite the low data transfer rate, it is still suitable for gathering sensor data, such as temperature and humidity, and is often used in home automation applications.

According to the ZigBee Alliance, this protocol can theoretically support up to 65,000 devices on a single network and can handle devices’ dynamic behavior (they can appear, disappear, and re-join the network later). Texas Instruments has proved that connecting 400 nodes is a real possibility.  

New devices can quickly join a ZigBee network as the “handshake” process takes only 30 milliseconds.

ZigBee operates on 2.4 GHz, the same frequency as Bluetooth. With its low power consumption, small devices such as door sensors can operate with a single battery for several years. This protocol does not use the IP addressing system, and needs a gateway to communicate with the Internet and personal devices, such as smartphones and PCs. 

The most recent version, ZigBee 3.0, was designed to transfer data through noisy RF environments that are common in industrial applications. 

Advantages:

  • Ability to connect up to 65,000 devices 
  • Low power consumption

Disadvantages

  • A custom gateway is required to control smart devices 
  • Limited data transmission distance
  • Prone to signal interventions as it uses the same frequency as Bluetooth and Wi-Fi devices
  • The gateway is expensive and a fee is required for every connected device 

6LoWPAN

6LoWPAN stands for IPv6 over Low-Power Wireless Personal Area Network. The idea behind this protocol is to permit even small devices with limited processing capabilities, such as sensors, to join IoT networks and transmit data over the Internet. 

In this communication protocol, interoperability is enforced only at the IP layer. Therefore, it can operate on both sub-1 GHz and 2.4 GHz frequencies.

There is a challenge related to the IP packet size. It is significantly larger than the packet size allowed by the 15.4 standard. The IPv6 Minimum Transmission Unit (MTU) is 1280 bytes, while 15.4 can carry up to 100 bytes of meaningful data. One solution is to break the MTU into smaller frames and transmit them individually. However, this fragmentation means if one small frame is lost, the whole packet is unusable.  

6LoWPAN is an open standard defined by the Internet Engineering Task Force (IETF). All specifications of this protocol have been freely available since May 2018. However, vendors need Thread Group membership to implement this protocol. 6LoWPAN uses the same IP level as internet protocols, therefore the gateway is easier to implement than it is for ZigBee and Z-Wave. 

Advantages:

  • Low power consumption 
  • The gateway is easier to implement  
  • Operated on multiple frequencies and can avoid the crowded 2.4 GHz frequency
  • Supports 64-bit and 16-bit addressing

Disadvantages:

  • Fragmentation increases the risk of receiving defective packets
  • It’s not very common, and hardware implementation is more expensive

Z-wave

Z-Wave is a wireless communication protocol introduced by a Danish company Zensys. It was designed to transmit small data packets at a rate of 100 kbit/s. Z-Wave operates at a different frequency in each country, which means owners of Z-Wave devices will need to purchase new ones if they decide to relocate. In the US, Z-Wave operates at 908.42 MHz. No matter the location, Z-Wave always avoids the overcrowded 2.4 GHz band and can theoretically support up to 232 devices. The latest version is Z-Wave Plus v2.

This smart building connectivity protocol is proprietary software supported by the Z-Wave Alliance and backed by industry leaders. It is updated and refined regularly, unlike some open-source software, such as ZigBee. 

Z-Wave is globally standardized, and all the specifications, such as Z-Wave interoperability and security were released to the public in 2016. This makes the standard easily accessible by IoT developers. 

Advantages:

  • Avoids the busy 2.4 GHz frequency      
  • All Z-Wave devices from different manufacturers are interoperable 
  • Low power consumption 

Disadvantages:

  • Limited data transmission capacity, which is suitable for devices such as light bulbs, but doesn’t have enough capacity for HD surveillance cameras     
  • Uses different frequencies in different countries
  • Premium price 

Comparison of Communication Protocols

All the above building automation communication protocols are based on the IEEE 802.15 standard, offer the same security level, and support mesh topology. But this is where the similarities end. The table below compares four of the most popular communication protocols.

Which Protocol Is Right for You? 

Every communication protocol has advantages and drawbacks and it is impossible to identify the best option without considering all the surrounding factors. 

For example, Bluetooth is a cheap option that offers a high data transfer rate and easy device control through a smartphone. However, it only allows eight devices to be connected. ZigBee supports up to 65,000 nodes (theoretically), but there is a fee for every connected device. Additionally, ZigBee requires a gateway to control IoT devices. Z-Wave side-steps the crowded 2.4 GHz frequency, but it is the most expensive IoT connectivity option, and it provides the lowest data transfer rate. 6LoWPAN is still largely overlooked, despite its scalability and expandability. 

If you are currently deciding which communication protocol to adopt for your IoT automation solutions, make sure you consider all relevant factors. It could be helpful to construct a table like the one presented in this article. Include the solutions you are considering, and all the parameters that can influence your choice.   

Author:

Nadejda Alkhaldi, content writer at Softeq Development.

Softeq is a full-stack development company with offices in the US and Europe. It offers full-cycle engineering services, such as producing a comprehensive IoT ecosystem from scratch. Softeq client portfolio includes a wide range of organizations, from startups to Fortune 100.


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