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PoC Rate Adjustments until HIP 55 / Validator Challenges

· 3 min read

The core developers are changing the PoC Interval from 475 to 950. Hotspots will PoC less often however total average rewards will remain unchanged. PoC rate has no effect on average individual Hotspot earnings, but may increase variability of rewards. This will help the chain process transactions more efficiently. Please read the details below for our reasoning.


The Helium Blockchain uses a work algorithm called “Proof of Coverage” (PoC) to verify that Hotspots are located where they claim. Today, Hotspots take on the responsibility of creating Challenges on the network. This responsibility changes with the recently approved and still being implemented HIP 55, which introduces a fixed limit of PoC challenges per block.

At this time, new Challenges are created every 475 blocks by Hotspots on the Helium blockchain. With over 600K Hotspots on the network and nearly 500K Hotspots creating those challenges, the network is trying to support almost 1,700 PoC transactions alone per block and over 2.4mm transactions per day.

The core developers believe that because of this, the network is currently bottlenecked on transaction processing. This is seen by payments taking longer to confirm, Hotspot onboarding taking longer, Oracle price submissions being rejected, and other transactions not clearing.

We believe that the blockchain is currently only able to support around 1,000 PoC transactions per block, the intended target for HIP 55. We believe that we need to adjust PoC Challenge Interval to match the intended effects of HIP 55 sooner than the launch of Validator Challenges. As we’ve done before, we will be increasing the PoC Interval, this time to 950. The last time we adjusted PoC interval, we immediately saw transactions start clearing more efficiently and more chain stability.

This is a significant change but will immediately relieve the chain from this bottleneck and give us time to focus on the last parts of testing HIP 55 and ship it next month. The goal of HIP 55 is to keep the amount of total PoC activity across the network fixed regardless of the number of Hotspots that come on the network. Also a reminder that there's always a fixed amount of HNT issued per month which means there's a fixed amount of HNT "available per block". This does not change at this time or after HIP 55.

For Hotspot Owners, you may see a reduction in daily PoC activity as we have seen before. Over a longer time frame, however, this activity will still be more consistent and reliable. We’ve seen reports of witness activity issues and this is directly related to transaction clearing. The blockchain will have less of a backlog of transactions to process and clear transactions faster.


We will be issuing this change today Friday, March 25 where we will be setting poc_challenge_interval to 950 around 2100 UTC / 02:00 PM Pacific Time. This immediate change should give us the headroom to support about 125k more Hotspots (well over a month at current Hotspot growth rate) actively generating challenges.