Z-Wave Long Range unlocks new possibilities for IoT automation

Since its initial development over 20 years ago, Z-Wave has been a leading network protocol for smart home and IoT devices. Operating in the 800 to 900 MHz frequency band, Z-Wave represents a crucial alternative to the crowded Wi-Fi whitespace for control and sensor applications. Historically, though, Z-Wave has been focused on the home automation space. The Z-Wave Long Range (LR) specification, first released in September 2020 and opened for third-party silicon certification in December 2020, changes the game. By increasing the range and scalability of Z-Wave networks while optimizing battery life and preserving interoperability, Z-Wave LR unlocks new possibilities for IoT product and application design.

The growing need for large-scale automation networks

The original Z-Wave protocol has an operating range of up to 100 meters per hop and can address up to 232 devices on a single mesh network. Those capabilities are sufficient for a fairly palatial smart home – but the Z-Wave Alliance recognizes a market need to address larger-scale applications. A company’s office could be as smart as the CEO’s home. A hotel or apartment complex could leverage the same energy management and touchless control features as a private residence. Z-Wave LR is designed to extend the benefits of Z-Wave in terms of both geography and devices.

Transforming the Z-Wave network while maintaining interoperability

Z-Wave LR is a 100 Kbits/s DSSS OQPSK modulation addition to the Z-Wave protocol. The modulation is treated as a fourth channel, allowing gateways to add LR nodes to the existing Z-Wave channel scanning. While traditional Z-Wave networks use a mesh topology, Z-Wave LR networks operate on a star topology. Instead of sending signals from node to node until the intended destination is met, as in a traditional Z-Wave network, a Z-Wave LR hub in a central location connects directly to all devices in the network.

Backwards compatibility is a core tenet of the Z-Wave specification, and Z-Wave LR is no exception. Both Z-Wave LR and traditional Z-Wave nodes can co-exist within the same network, enabling a wide variety and combination of Z-Wave and Z-Wave LR devices.

Silicon Labs has already made the first implementation of Z-Wave LR available to new and existing customers on the Z-Wave 700 platform through a firmware upgrade. If both the hub and the controlled devices in a Z-Wave network have Z-Wave LR, the network can support both star and mesh topologies simultaneously.

In any case, however, upgrading existing Z-Wave networks to Z-Wave LR won’t cause previously installed devices to stop communicating. Z-Wave and Z-Wave LR are designed to co-exist on the same network, with LR network nodes reserved for new or existing Z-Wave mesh network devices to preserve both backwards and forwards compatibility and sustain interoperability between certified Z-Wave devices.

Z-Wave and Z-Wave Long Range network topology (Image: Z-Wave Alliance)

Massive upscaled coverage area and nodes

What does Z-Wave LR offer on this new topology? Exponentially expanded opportunities. The Z-Wave LR signal is output at up to +30 dBm, compared to traditional Z-Wave at -1 dBm. This increased power allows Z-Wave LR signals to travel a mile or more on a single hop. The first implementation of Z-Wave LR, on the 700 Series platform from Silicon Labs, has a proven transmission distance of 1 mile (1.6 KM) direct line of sight at only +14 dBm. Future implementations could theoretically exceed that already impressive mark by several more miles.

Prior to Z-Wave LR, it would have taken multiple signal repeaters to carry Z-Wave signals beyond the walls of the home. Now, it’s easy to envision a Z-Wave LR network blanketing an entire property without the need for repeaters. The ability to easily add devices to the distant edges of an automation network opens up new opportunities for what can be automated.

In order to make room for these new opportunities, Z-Wave LR MAC address space has been expanded from 8 bits to 12. A Z-Wave network can therefore accommodate up to 4,000 devices. Compared to traditional Z-Wave’s 232 nodes, this 20× increase in available nodes makes Z-wave networks a practical option for applications across light commercial, industrial, hospitality, and multi-dwelling unit (MDU) projects.

For a full technical comparison between traditional Z-Wave and Z-Wave LR, see below.

Z-Wave & Z-Wave Long Range Technical Comparison Chart (Source: Z-Wave Alliance)

Longer battery life for lower intervention networks

Z-Wave allows a system designer to add more devices to the network and place them in farther-flung locations: two capabilities that would be fairly useless if the system owners also have to either run power to each device or constantly replace its battery. Z-Wave has always enjoyed advantages over other protocols like W-Fi in terms of power consumption. Now, Z-Wave LR leverages dynamic power control to offer 10-year battery life on a single coin-cell battery. Using this new feature, the Z-Wave LR devices automatically adjust and optimize the radio output power at every transmission.

Dynamic power control allows the system owner to install a sensor and not have to worry about it for a decade. That “set it and forget it” capability makes it feasible to deploy sensors in hard-to-access locations: behind walls and under floors, or in attics, basements, and utility closets. Using Z-Wave LR , future applications will be able to build the sensor networks required to drive context-aware artificial intelligence (AI) for IoT applications.

New frontiers for Z-Wave LR are still emerging

Currently, Z-Wave LR will only be available in the United States. The Technical Workgroup is evaluating and testing to ensure compliance in order to support Europe and APAC regions in the future. More developments are sure to follow.

To keep up with everything Z-Wave, visit the alliance website at http://www.z-wavealliance.org.