As we started on the journey to build out a smarter home, our first challenge was the vast array of technologies. Over the last 20 years, the market for smart devices has grown rapidly. Along with that, there has been a proliferation of standards and protocols. In this post, I’ll compare some of the these technology options.
Proprietary systems
If you’re getting started, there’s no shortage of vendor-specific proprietary options. From Amazon’s Sidewalk to the original Samsung SmartThings cloud-connected devices, vendors have provided their own ecosystem for devices. These devices have the benefit of being quick and easy to setup and configure. However, they come with significant downsides: vendor lock-in and small ecosystem. Things that understand the vendor’s system may all work well together, but it’s often difficult or impossible to connect other devices into the system. My Samsung washing machine is a great example. It connects to the Samsung cloud and can only be controlled via the proprietary SmartThings app. I can’t coordinate it with any other devices.
In general, these systems are not interoperable and don’t age well, so I won’t dive into them here. In fact, I recommend strongly that you stick with open standards and protocols whenever possible. That said, historically this has been the easiest way to get started with IoT devices. Matter (see below) is trying to change that.
Z-Wave
Released in 1999, Z-Wave is a wireless protocol designed for automation. It uses the frequency band 908-916 MHz in the US (912-920 MHz for Z-Wave LR), with other parts of the world using frequencies between 865 and 926 MHz. This has the benefit of not competing with the frequencies used by Bluetooth, WiFi, and other competing networking standards. It’s a very mature technology with a solid ecosystem of devices. The Z-Wave Alliance has a certification program to ensure interoperability between devices.
Strengths
- Large community of highly interoperable devices
- Uses frequencies below 1 GHz to avoid interference with other devices
- Supports up to 232 devices per mesh with an operating range of up to 100 meters between devices
- Z-Wave LR (long range) supports up to 4,000 devices in a star network and can transmit up to 1 mile (1.6 km)
- Chipset is optimized for low power consumption, making it ideal for battery-powered devices
Weaknesses
- Relies on a proprietary chipset
- Requires a central controller
- Low data rate (40-100kbps)
- OpenZWave open source libraries are no longer maintained
Zigbee
Standardized in 2003 as IEEE 802.15.4, Zigbee is a low-power, low-data-rate wireless networking standard. It operates in the 2.4 GHz frequency band and is designed for short-range communication between devices. Zigbee is widely used in home automation, industrial control, and medical applications and supports mesh, start, and tree networking. Each network requires a coordinator device. Globally, it primarily operates at 250 kbps in the 2400–2483.5 MHz band (2.4 GHz) using 16 channels, although the specification allows for sub-1 GHz operation at 20 kbps in country-specific frequency ranges. It is designed for low power consumption and higher data rates, so it has a line-of-sight range of 300m outdoors (100m indoors). Practically, that means a range of 10m to 100m is not unusual. The market is very mature and offers certification, but differences in implementations can lead to interoperability issues.
Strengths
- Higher data rate (250 kbps)
- Large network supported (65,535 for mesh networks)
- Low battery consumption
- Mesh network latency typically low across varying payload sizes
Weaknesses
- Lower broadcast range
- Single controller per network
- Primarily uses 2.4 GHz band, so subject to interference from WiFi and other devices
- Interoperability issues can exist between devices from different manufacturers
Bluetooth
One of the most well-known standards, it was developed under IEEE 802.15.1 and uses frequency band 2400 MHz–2483.5 MHz, divided into 79 channels (or 40, for Bluetooth Low Energy). It is commonly used for short range and point-to-point connectivity and can achieve data rates of up to 2 Mbps in a range of under 10m. Class 1 industrial devices are capable of ranges of 1 km or more, although extended ranges often require a reduced data rate (125 kbps).
Strengths
- Low power consumption
- Very common and well-supported
- Offers proximity/location detection
- High data rate for devices in close proximity
- Often has exceptional battery life (BLE)
- Bluetooth Mesh supports 32,000 nodes and 127 hops
Weaknesses
- Mesh performance degrades with larger payload sizes and hops
- Limited range (1m - 10m) for optimal performance
- No IP-addressing available
- Meshed nodes limited by bandwidth, creating a practical limit as low as 100
- Subject to interference (2 GHz band)
WiFi
This one needs little introduction. In fact, odds are you’re reading this on a WiFi-connected device. WiFi is based on the IEEE 802.11 standards. It operates in the 2.4 GHz, 5 GHz, and 6 GHz bands, with data rates ranging from 1 Mbps to 46 Gbps.
Strengths
- Fastest data rates
- High range
- Supports large data transfers, making it ideal for video and audio streaming
- Simple to setup and manage
- Highest performance occurs in 5 GHz and 6 GHz bands (less interference)
- Supports roaming between access points
Weaknesses
- Highest power consumption
- Higher frequency bands have lower range
- Multiple aspects of protocol (WiFi version, encryption version, etc) can affect interoperability significantly
- Mesh systems may use additional frequency bands or sacrifice significant portions of bandwidth to support multiple devices
- Devices must create a point-to-hub connection to communicate
- Most IoT devices are limited to older protocols and 2.4 Ghz band
Thread
Thread is an IPv6 based mesh networking technology designed for low-power devices. It was developed by the Thread Group, whose members include Google (Nest Labs), Apple, Samsun, OSRAM, Silicon Labs, Qualcomm, and many others. It relies on 6LoWPAN and IEEE 802.15.4 (like Zigbee) for IP-addressable, encrypted mesh communication. It uses the 2400 MHz–2500 Mhz band, divided into 16 channels. Thread relies on a border router to bridge Thread and non-Thread devices, and it allows multiple border routers to be configured (although that is generally not necessary). Thread support is included in newer phones, such as the Apple iPhone 15 Pro (and later) and Google Pixel 9 (and later). Thread networks support 16,384 devices per network (32 routers and 511 children per router). Threads devices can act as routers (forwarding packets to their destination) or as end devices (communicating through a device that is a router).
Making this somewhat more complicated, there are two types of Thread devices. Thread devices that have continuous power (such as light switches and outlets) are often classified as a Full Thread Device (FTD). They have a permanently active radio. A Full Thread Device can act as a Router, Router Eligible End Device (REED), or Full End Device (FED). A REED device can promote itself to a Router to improve connectivity, while a FED is always simply an end device. For a healthy Thread network, you want multiple FTDs that are near each other and can act as routers. They will create the mesh network, automatically providing routing services and connectivity for new devices. Thread tries to optimize the network by having 16-23 active routers available.
Devices that need to be able to sleep and are not continuously powered (such as battery-operated sensors) are typically considered a Minimal Thread Device (MTD). These devices can be classified as Minimal End Device (MED) or Sleepy End Device (SED). A MED has a transceiver that is always enabled, but it does not need to poll its parent. An SED has a transceiver that is normally disabled, but it wakes up occasionally to poll its parent. These kinds of devices cannot route messages, so they are always end devices.
Strengths
- Mesh is encrypted, resilient, and self-healing
- IPv6 based, allowing for direct device addressing
- Fast growing ecosystem with support from many major vendors
- Promotes standardization across manufacturers
- Natively supports IPv6
- Open standard with open source border router implementation
- No central hub required
- Fast data rate (250 kbps)
- Spread-spectrum frequency usage reduces interference
Weaknesses
- Relatively new
- Multiple border routers from multiple vendors can negatively affect performance and stability
- Limited troubleshooting options
- Requires IPv6 to operate (which can be a challenge for some devices, such as Google Nest WiFi which has specific requirements to enable support)
- Range for many commercial devices is often limited to under 10m
- Depends on having enough router devices to support the network
- Vendors are frequently not clear in declaring a device is an FTD (and routing capable), a FED, or an MTD
- Interference from other 2GHz devices can prevent communication
- Google and Apple hubs that support Thread do not have configurable channels (yet)
- Not suitable for video streams or large data transfers
Matter
In 2019, Amazon, Apple, Google, Samsung SmartThings, and the Zigbee Alliance (now called the Connectivity Standards Alliance) started the Project Connected Home over IP (CHIP) working group (which became Matter). The specification is published as an open standard, and there are open source implementations available. You might notice that many of the vendors that are now part of this process are also involved with the Thread standard.
Unlike the others, Matter is not a protocol. It is an IPv6-based standard designed to work over multiple protocols to connect and manage devices within a local network. That means it works on top of Ethernet, WiFi, and Thread. In fact, devices like cameras and smart speakers will be able to use WiFi (supporting the additional bandwidth needs), while light switches and sensors can use Thread.
The idea behind Matter is to try to make the various smart devices easier to setup and ensure they work well together. It’s also designed to make local control the default experience (rather than cloud-based or proprietary systems). As a result, Matter does not require a proprietary hub or even Internet connectivity.
Most devices you’ll find on the market today are likely to be Matter-over-WiFi (often using 2GHz), but there are an increasing number that are Matter-over-Thread. In both cases, the device must be able to connect to its network, and the device must be reachable by IPv6 in order to be provisioned. That can sometimes be challenging, depending on the networking configuration. For example, I had a Google Nest WiFi. It fully supports IPv6, but only if I connect it directly to my fiber modem. It can’t be behind another device, such as a router (otherwise, it becomes IPv4 only).
Strengths
- Highly interoperable and supported by most major IoT vendors
- Relies on open standards
- Build on IPv6
- Multi-admin control (allows multiple hubs – such as Apple HomeKit and Google Nest Hub – to control the same devices seamlessly)
- Does not require cloud connectivity (but can use it to support firmware updates for devices)
- Typically just requires scanning a QR code with a Bluetooth-capable device to add components
- Local control of devices (lower latency, higher reliability)
- Single, shared setup experience for all devices
- Can be used with bridges to connect to other protocols (such as Zigbee and Z-Wave)
Weaknesses
- Devices just entering the market (started in 2023)
- Requires IPv6, which can be challenging with some routers and devices (and difficult to troubleshoot)
- Not all device features are supported, so some functionality may not be available on Matter
- Some device types are not supported, including many major appliances
- Smart cameras are not supported, although it may arrive in Matter 1.5 (Spring 2025)
- Error messages when commissioning Matter devices can be vague and unhelpful (worse on Apple devices than Google)
- Mixing Matter-over-Thread and Matter-over-WiFi devices can require some planning to avoid interference