The Wi-Fi Alliance, the organization that drives Wi-Fi adoption and evolution, has simplified the names of commonly used Wi-Fi generations with a numerical nomenclature, e.g., Wi-Fi 4 = 802.11n, Wi-Fi 5 = 802.11ac and Wi-Fi 6 = 802.11ax. Chances are, you are using one of these flavors of Wi-Fi in your home or workplace.
Despite the ubiquity of Wi-Fi 4/5/6, the rapid growth of the Internet of Things (IoT) has forced a rethinking of traditional Wi-Fi, revealing technological gaps and redefining the roles 802.11 protocols should play in today’s wirelessly connected world of ultra-low-power IoT devices. The higher demands for long-range connectivity and low power requirements of IoT and machine-to-machine (M2M) applications are driving the need for another type of Wi-Fi optimized for the IoT.
The Wi-Fi HaLow (pronounced HEY-low) protocol fills these gaps by providing an ultra-low-power wireless solution that connects larger numbers of IoT devices at much longer distances and at much lower power than traditional Wi-Fi. The protocol was ratified by the IEEE 802.11ah task group in 2016 and dubbed Wi-Fi HaLow by the Wi-Fi Alliance.
The Wi-Fi HaLow standard’s unique combination of energy efficiency, long-range connectivity, low latency, HD video quality data rates, security features and native IP support makes it an ideal protocol choice for wirelessly connected, battery-powered IoT devices. Let’s take a closer look at some of the primary differences between Wi-Fi HaLow and traditional Wi-Fi and why the 802.11ah protocol is ideally suited to meet the connectivity requirements of IoT applications.
Wi-Fi HaLow chip requires a fraction of the power of a conventional Wi-Fi chip. While the higher data rates of traditional Wi-Fi enable users to stream HD video content and download massive files quickly using wide channels in the 2.4 GHz, 5 GHz and 6 GHz bands, the effective distance for these Wi-Fi connections is short, and they drain batteries quickly, requiring frequent charging or battery replacements, or ideally a mains power connection. For these reasons, Wi-Fi HaLow is a better choice for power-constrained IoT devices that need to reach longer distances and run on batteries for years while still offering many Mbps of data throughput.
The sub-1 GHz signals of Wi-Fi HaLow use narrower channels from 1 MHz and up compared to the narrowest 20 MHz channels used by traditional Wi-Fi. This 20x factor in bandwidth translates into a 13 dB of link budget improvement thanks to the lower thermal noise in the channel. RF frequencies between 750 MHz – 950 MHz versus traditional 2.4 GHz Wi-Fi account for an additional 8-9 dB of link budget, saving free space propagation loss. In addition, the Wi-Fi HaLow protocol added a range-optimized modulation and coding scheme (MCS10), which provides an additional 3 dB link budget boost.
Providing end users with a wireless IoT solution that reaches hundreds of meters — without additional extenders or costly cellular data plans — is a key competitive advantage for the 802.11ah protocol. With its long-distance reach, the benefits of Wi-Fi HaLow extend the range of smart homes and smart city networks, enabling users to control IoT devices beyond 1 kilometer, and well beyond the reach of traditional Wi-Fi protocols.
Better Signal Penetration
Sub-GHz Wi-Fi HaLow signals can pass through walls and other obstacles more easily than possible with traditional Wi-Fi. The variability of construction materials and layouts of homes and commercial buildings have less effect on sub-GHz HaLow signals than Wi-Fi protocols in the 2.4 GHz and 5 GHz bands. The superior reach of Wi-Fi HaLow through walls and buildings can help reduce customer service calls and product returns that sometimes plague products using conventional Wi-Fi. Device manufacturers can be assured of robust HaLow connections to an access point (AP), whether their products are located inside or outside, or whether in a basement or attic of a home.
A Highly Scalable Solution
A single Wi-Fi HaLow APcan address up to 8,191 devices, more than 4x as many devices as a traditional Wi-Fi AP. That’s ample capacity to connect every LED bulb, light switch, smart door lock, motorized window shade, thermostat, smoke detector, solar panel, security camera or any imaginable smart home device for the foreseeable future. Typical Wi-Fi routers for the home generally support tens of devices. When deployed in a home by a broadband service provider, a single Wi-Fi HaLow AP can become a scalable platform for delivering additional security and utility management devices and services.
License-free Spectrum with Noise Immunity
Like traditional Wi-Fi in the 2.4 GHz, 5 GHz and 6 GHz bands, Wi-Fi HaLow enables end users to own their equipment and use license-free sub-GHz radio spectrum, ranging from 750 MHz to 950 MHz.
Operating within the ISM band, Wi-Fi HaLow can use a variety of channel bandwidths: 1 MHz, 2 MHz, 4 MHz, 8 MHz and 16 MHz. The narrower the bandwidth, the farther the signals can travel. Data is transmitted in packets spread across multiple sub-channels using OFDM, which enhances performance in challenging RF environments, especially when there is strong interference from other radio devices. Forward error correction (FEC) encoding also provides additional protection for recovering packets, ensuring robust connections.
Secure and Interoperable
Wi-Fi HaLow, like other IEEE 802.11 Wi-Fi versions, is an inherently secure wireless protocol. It supports the latest Wi-Fi requirements for authentication (WPA3) and AES encryption of over-the-air (OTA) traffic, with data rates that enable secure OTA firmware upgrades.
Just like other types of Wi-Fi, HaLow is a globally recognized standard (IEEE 802.11ah) that defines how connected devices authenticate and communicate securely. Equipment vendors using Wi-Fi HaLow have the assurance their products and networks will interoperate by following Wi-Fi Alliance development guidance. Because it is part of the IEEE 802.11 standard, a Wi-Fi HaLow network can also coexist with Wi-Fi 4, Wi-Fi 5 and Wi-Fi 6 networks without impacting their RF performance.
Going Native with IP
All IoT networks require Internet protocol (IP) support for cloud connectivity. Because Wi-Fi HaLow is an 802.11 Wi-Fi standard, it provides native TCP/IP support. This built-in IP capability means no proprietary gateways or bridges are needed for IoT connectivity. All client devices connected to a Wi-Fi HaLow capable router can use IPv4/IPv6 transport protocols for direct access to the Internet for cloud-based services and management of IoT data.
The HaLow Effect: Extending Reach, Expanding IoT Possibilities
The network congestion, range limitations and higher power consumption of traditional Wi-Fi, along with the limited number of devices that can be connected to a single AP, are no longer viable for today’s connected world of IoT devices. These limitations impede new IoT-centric business models that are emerging across industries, including surveillance, smart home, clean energy, retail, industrial IoT, and building automation, which require longer range, greater capacity, and more flexible battery and power management options while minimizing deployment costs. Indeed, Wi-Fi HaLow stands out among traditional 802.11 protocols for its extended reach, energy efficiency, capacity and versatility.