The Helium 5G radio limit.

What is a radio limit?

In HIP74, Helium has proposed a limit to how many radios could earn rewards if they provide coverage in the same hex. There is currently a limit of 5 radios.

How the limit works

There are a couple of things to remember when setting up 5+ radios. First, the five radios that will earn rewards are not random. It's based on signal levels and what time CPI approval was approved.

Signal levels:

If you are not familiar with the new Helium 5G explorer, you can access the new Helium explorer here: https://coverage-explorer.herokuapp.com/ or check out our blog here for a quick rundown: https://www.heliumdeploy.io/blog/the-new-5g-helium-explorer.

I will be using this overcrowded 5G area as an example. The area has way too many radios, and many will not get any rewards. You can follow along by viewing them here: https://coverage-explorer.herokuapp.com/hex/08c29a54dbb6a9ff. There are a total of 30 radios at the moment.

On the left side of the explorer, we can see each Radio by its ending serial number. 0009 is one Radio, 0014 is another one, etc. these are all providing coverage to this hex: 08c29a54dbb6a9ff.

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Let's focus on radio 0009. This is the coverage it provides. It has a signal level of -75.74 for this hex in white.

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Now let's look at Radio 0014 coverage.

https://coverage-explorer.herokuapp.com/hex/08c29a54dbb6a9ff/1647

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This radio 0014 has a signal level of -92.94 in the white hex below.

To give an idea. The lower the signal, the better. -75 is better than -92. Radio 0009 would earn the rewards if the limit were 1 per hex.

Here are all 30 radios in this hex with their signal levels.

After we do a bit of excel magic, we can see who will earn tokens here.

Radio 0030, 0101, 0009, 0082, and 0037 are the winners in this hex with the best signal. All the rest will not earn for this hex.

Let's look at how many mobile tokens they are getting/losing.

The first five radios will earn a total of 523.2 Mobile tokens, using the 6.54 estimate per coverage point. The other 25 lost a total of 2066.64 Mobile tokens. Those tokens would be distributed amongst all the daily payout. They are not "lost forever."

This is only for one hex. We can see many overlaps on radio 0009. Here is a rough outline in pink of radio 0009 on top of radio 0014. All the overlapping hexes could result in zero rewards per hex depending on if there are 5+ covering this hex and signal levels.

Time deployed

If the radio signal levels are the same, they will pick which Radio got CPI approval first.‍

coverage_claim_time is the timestamp when the Radio received the spectrum access grant for the first time. To prevent rewarding "dead" Radios, we propose to reset coverage_claim_time if the Radio was not generating a Heartbeat for more than 72 hours and use the time of the last Heartbeat as the new coverage_claim_time.‍

Here's an example.

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Radio 0039 will earn rewards since it was deployed before radio 0037.

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Closing thoughts

The effects of HIP74 are not in effect yet. But it is wise to check your location before deploying to see if you have competition. This will prevent lower rewards in the future and an edge over the rest of the radios around you. Also do not install more than 5 radios per location to prevent reward degradation.

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