Best of Both Worlds








Since the introduction of the LP WAN radio frequency systems (LoRa WAN, SigFox, Taggle etc.) a lot has been learned about the suitability of the radio frequencies they use for remote monitoring.
Although lower frequencies (433MHz, 70 MHz) offer longer range, the available bandwidth is limited and users must share the free-to-air allocation with multiple other users. The “sub 1GHz” band does trade off range, but it comes with the benefit of having far greater bandwidth and the ability to serve many more users. Although many people have claimed ranges of up to 20km,  that is only possible in ideal conditions and with short transmissions. For practical environmental monitoring range is typically 3 to 5km. One limitation of LoRa WAN has been its lack of a repeater capacity. This function has been added to the protocol but has not translated to readily available devices. Another difficulty has been the focus of the designers on small packet length and infrequent transmissions: two factors that are out of synch with what is required in remote environmental monitoring.
However, what is probably the greatest limitation of the LP Wan services is that the “IP” connection does not make it to the node. Instead, nodes are given identifiers unique to the system in which they are used. The connection is not live: devices can receive data (and sometimes that is all they can do) but do not support bi-directional real time data communications.
Which surely begs the question of “why can’t I have a low power radio system which supports live data sessions and uses standard IP style addressing?


Introducing HaLow



HaLow was added to the WiFi standards in 2021 but has struggled to attract the attention of developers. It is being championed by Morse Micro, who are based in New South Wales and headed up by ex Silicon Valley WiFI experts. The motivation for HaLow could have been exactly our “Use Case”: for a license free, open, radio system, capable of supporting several hundred devices, each of which was transmitting every 10 minutes.
That is pretty much a perfect match for our applications.
There are two ways to implement a HaLow system: the first is a simple point-to-multi- point system, where a central HaLow Access Point communicates with HaLow nodes installed around it. This is just like a “normal” WiFi system. The biggest difference being a designed range of 1000m.
The second way to use HaLow is as a “Mesh”. Here each node can act as a Repeater, passing on traffic from more distant nodes to the Access Point (Gateway). This allows the size of a network to be increased significantly.
Because HaLow Access Points are based on the same technology used in standard WiFi Access Points, they are simple to build. The only difference being the substitution of the 2.4/4.8 GHz radio modem for a HaLow modem.
There is however one caveat: drop in HaLow modules are not available yet, so developers must write code to communicate with the module they use. Once command compatible HaLow modems become available, on chip HaLow devices will become as common as the ESP8266 modules which have been so instrumental in the growth of 2.4 GHz WiFi devices.


WiFi HaLow is Coming



We have been testing a range of HaLow modems and Gateways and our results to date have been very pleasing. We are now waiting for our telemetry partners to commit to a HaLow version of their WiFi products.