900 MHz frequency range Range record for Wi-Fi HaLoW

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In Joshua Tree National Park in California, a Wi-Fi network based on the IEEE 802.11ah standard achieved a range record of 16 kilometers (approx. 10 miles). This opens up new possibilities for Wi-Fi networks and IoT applications, especially in rural areas.

Morse Micro has successfully demonstrated HaLoW Wi-Fi capabilities in rural Joshua Tree National Park, USA, achieving a 16 km (10 miles) transmission range. The test maintained a stable data transfer rate of 2 Mbit/s using the 900 MHz frequency band, showcasing the potential of long-range, low-power Wi-Fi for remote and rural applications.

Wi-Fi HaLoW, also known as IEEE Standard 802.11ah, is a variant of the wireless standard published by the Wi-Fi Alliance. Compared to most other Wi-Fi standards, Wi-Fi HaLow uses frequencies in the sub-GHz range around 900 MHz. This allows lower data rates to be achieved than the 2.4GHz, 5GHz or 6GHz Wi-Fi networks commonly used in home applications. However, Wi-Fi HaLoW networks are significantly more energy-efficient and designed for particularly long bandwidths - the IEEE 802.11ah standard specifies a typical range of up to one kilometer in an urban environment. "HaLoW" is a term published by the Wi-Fi Alliance that summarizes the characteristics of the standard - high energy efficiency ("High"), and ("and") low bandwidth ("Low") with Wireless connectivity.

Better network coverage, especially in rural areas

However, these ranges can be increased even further: back in January, Morse Micro reported that it had achieved stable connection distances of up to three kilometers in urban tests with one of its evaluation kits. Wi-Fi HaLoW is also considered a technology that could be used to bridge dead spots in rural areas, for example. The most recent test in Joshua Tree National Park in California demonstrates the potential in this area of application.

For the tests, a commercially available evaluation kit was used as an access point (AP) on the edge of a quiet rural valley. The MM6108-EKH01 kit is based on a Raspberry Pi 4 with the Morse MM6108-MF08651 Wi-Fi HaLow reference module and outputs 21 dBm (125mW) via a standard 1 dBi low-gain dipole antenna. This results in a total radiated power of 22 dBm, but still allows operation within the parameters specified by the 802.11ah standard. This allows the range to be increased without the need to use additional directional antennas with high gain, for example.

Double the data rate is also possible with a shorter range

Morse Micro's chips comply with the 802.11ah standard, which specifies a slot time of 52µs. Morse Micro's implementation allows a maximum flight time of 53µs to allow for slight variations between devices. This results in a theoretical maximum range of 15.9 km (about 10 miles), which was achieved during the tests in Joshua Tree National Park.

These are of course ideal conditions—the Californian national park has little forest cover and very low background noise, which makes the area extremely popular for radio tests. Nevertheless, it provides good indicators for the general use of the technology, especially in rural areas.

Theoretically, Morse expected a connection with a sensitivity of -95 dBm, which would enable a throughput of 4.5 Mbit/s or a UDP-MAC throughput of 4 Mbit/s. However, this does not seem to be quite enough for the maximum possible range. However, this does not seem to be quite sufficient for the maximum possible range for the desired data throughput: In the tests in Joshua Tree National Park, a stable connection with a UDP throughput of 2 Mbit/s was achieved at 15.9 km (10 miles) , but this should still be an attractive data rate for many IoT applications.