Recommendations for LoRaWAN coverage in a reinforced-concrete high-rise (US915, AWS IoT Core)

LPWAN Industrial Gateways / Concentrators
1

Hi all,

Looking for real-world advice from anyone who’s tackled multi-floor concrete construction with LoRaWAN. Sharing our summarized test data below in case it’s useful context, and would appreciate any suggestions on repeater/relay approaches, gateway placement strategies, or things we haven’t considered.

Setup:

  • Building: high-rise, reinforced concrete construction in all directions (floors and walls)
  • Gateway: RAK WisGate 7268V2, US915, connected to AWS IoT Core for LoRaWAN
  • Sensors: STM32WLE5-based, custom firmware, currently deployed on floors 6, 7, and 8, with the gateway on floor 7
  • Backend: custom AWS pipeline (IoT Core → Lambda → RDS) capturing RSSI, SNR, spreading factor, and link margin per uplink

What we’re seeing:

  • Same floor as gateway (0 floors separation): consistently strong — ~40 dB link margin, positive SNR, zero packet loss over multi-day testing
  • One floor of vertical separation (either direction): notably weaker than expected — link margin dropping to 10-24 dB range, SNR frequently negative
  • One of the two one-floor-separated sensors is also seeing real packet loss (~35-40% of expected packets missing based on FCnt sequence gaps), while the other at a similar margin isn’t yet — so there’s also an asymmetry we haven’t fully explained (possibly differences in local obstruction/equipment near that specific sensor, still investigating)

Our original simulation-based estimate was roughly 1 gateway per 3 floors for this construction type, but based on actual field testing, even 1 floor of separation is producing marginal-to-unreliable performance. We’re trying to figure out the most cost-effective way to close that gap without going to a gateway on every floor.

Questions for the group:

  1. Has anyone successfully deployed a repeater/relay solution (proprietary or standards-based) that works with US915 + AWS IoT Core for LoRaWAN?
  2. In similar reinforced-concrete multi-floor buildings, what gateway-to-floor ratio has actually worked for you in practice, versus what simulation tools predicted beforehand?
  3. Any experience with RAK-specific relay/repeater capabilities, or antenna/placement tweaks that meaningfully helped with floor-to-floor penetration before resorting to additional gateways?

Appreciate any input — happy to share more detail on our data/methodology if useful.

Thanks!

2

Hi @joedonn

Given the difference you’re already seeing between the two sensors one floor away, I wouldn’t rely too much on a fixed estimate yet.

Since you already have a pilot setup running, it may be worth using that gateway to survey more representative locations on each floor before deciding on the final gateway count. That should help show whether the weak spots are mainly caused by the floor slabs or by local obstructions around individual sensor locations.

You could also use one of our LoRaWAN Field Testers for this project - LoRaWAN® Field Tester Solution for Reliable Network Testing - RAKwireless - IoT Made Easy