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0045-lorawan-frequency-plan-selection.md

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HIP 45: LoRaWAN Frequency Plan Selection

Problem Statement

There are over a dozen of officially recognized LoRaWAN channel plans cited in the LoRaWAN Regional Specification:

image single-layer

The same document also provides guidance for eligible channel plans and "LoRaWAN® Certified devices with Regulatory Type Approval":

image single-layer

In each region, the Helium Network must select one and only one frequency plan (based on current design constraints). In cases where only one channel plan is possible (eg: Anguilla) or where only one has regulatory type approval (eg: American Samoa), the selection for the Helium Network may default to that one.

From the snippet above, you can see a few cases where selection is not so straightforward:

  • Afghanistan, Angola, Antartica, Antigua and Barbuda, Aruba: there is no channel plan suggestion nor is there one support for regulatory type approval
  • Aland Island, Albania, Algeria, Armenia: there are multiple potential plans but not support for regulatory type approval
  • Australia: there are two potential plans and both have regulatory type approval

These cases each special consideration which requires deep technical expertise and local knowledge. This same reasoning also extends to countries that may not yet have ISO 3166 recognition.

These configurations are currently encoded within the helium/miner project; this encoding may sometimes have mismatches even for even the easily defined and those may often be implemented quickly as "bug fixes". However, for the more ambiguous regions, disambiguation lacks rigor and process.

Solution

This HIP strives to solve the problem of choosing a single frequency plan per region. We believe this is an important assumption as while the network is growing rapidly, providing core coverage on a specific frequency plan and sub-band is critical in providing predictability for users. In other words, fragmenting a nascent network would leave to both confusion and difficulty roaming within even the same region.

Upon joining the LoRaWAN Alliance as contributing member, DeWi also formed a LoRaWAN Technical Committee "to help steer the Helium Network’s LoRaWAN infrastructure towards maximizing value for the LoRaWAN community at large." The membership of this committee includes many other contributing (and founding) members of the LoRaWAN Alliance and as such, includes deep technical and business knowledge of the ecosystem.

This HIP proposes that the DeWi LoRaWAN Committee may call for an initial assignment or change of frequency plan per region and/or country.

  1. Upon doing so, the DeWi LoRaWAN Committee will open a Pull Request (PR) to the helium/docs repository marking the change and providing the reasoning for the change. The announcement should also be made on the local Discord channel(s) and any other standard DeWi announcement channels.
  2. There will be a minimum four-week window during which a public commentary will be open under the PR. During this period, anyone can propose a formal dissenting opinion with counter-arguments to the proposed change and must provide alternate solutions if possible.
  3. Should the discussion have any formal dissent, a live virtual public forum will be in attempt to reach consensus. The author of the dissenting opinion must be ready to take the floor to represent their position.
  4. If the change remains contentious, the decision will go to on-chain voting. Currently, that would be implemented using Helium Vote mechanism where 1 hotspot in the concerned region equals 1 vote. Votes are cast by doing a DC burn transaction towards the appropriate wallet. A hotspot must be asserted in the concerned region for the entire duration of the vote, which must last at least seven days.

After steps 2 and 3, before proceeding to the next escalation, DeWi's LoRaWAN Committee may withdraw their proposal and reissue a new proposal at anytime. This would effectively restart the process at step 1.

Rationale and Alternatives

An alternate approach would be to allow any hotspot operate to choose any legal frequency plan. For example, operators in Australia could select AU915 or AS923-1 when they assert location. We believe this to be problematic as it will lead to fragmentation of coverage and confusion on behalf of network users. Instead, we believe such mechanisms would be useful for expanding into additional subbands.

Deployment Impact

A change in frequency plan could potentially cause certain devices to not be eligible for operation under the new frequency plan, either due to hardware or legislative constraints (ie: lack of certification to transmit on the new frequencies).

Assuming a device is physically and legally capable of adopting the new plan, the adjustment will only be possible if the vendor's firmware reads the frequency plan indicated from the Miner or Light Gateway client and applies the new frequency plan to the packet forwarder utility which configures the SX130x front-end.