NLOS Performance


(Ato) #1

I’m experiencing disappointing link performance in the presence of multi-path (NLOS channel , or actually very near LOS channel): PER > 50% while RSSI is -60dBm …
I looked into other references and saw the following: https://www.hindawi.com/journals/wcmc/2018/6931083/
The author points out a sever performance degradation in the presence of multi-path channels for SF9 and below.
Did anyone observed the same? any mitigation?
Thanks!
ATO


#2

how ? what’s your setup to measure this… does that system operates with lora/lorawan ? interesting :sunglasses:

Considering the three conclusions, one should agree that perhaps the most credible statement regarding the influence of the multipath propagation on the LoRa performance is one included in Conclusion 1. It states that out of the three configurable parameters (SF, BW, and ), only SF has an apparent influence on PER, by providing a clear division of the configurational space into two regions: the multipath-immune (or 0% PER) region for SF = 12–10 and the multipath-sensitive (100% PER) region for SF = 9–7.


(Ato) #3

I don’t have nay additional information on the article. in my own case I used SF7 and observed few spots along a line where the RSSI is good but the PER is awful and very sensitive to blocking the line of sight. using simple controller and HopeRF module in both sides with (assumable) Omnidirectional antennas.


#4

ADR could solve a lot … let the backend select the right spreading factor


(Ato) #5

I’d like to have a deterministic timing, synchronous communication, and ADR would fail it (or complicate it much)…


#6

Not all (new) technology is suitable for all use cases off course… but maybe you can make it work.

To overcome 'bad reception in a rural/forrest area and for some project a while back, I have been thinking (idea) about a little platform, with in the middle a gasfilled balloon.

This platform is connected to the (mobile) ground station with a steel cable.
the platform itself is stabilised like a drone, have rotors and a gps and is capable of 'hoovering on the same spot (more or less)
motors (and onboard electronics like gateway/camera’s/solarpanels ect ) are electrically connected through the groundstationcable.

Main idea/objective then, was to put antenna’s up in the air and increasing the coverage off that particulair area.


(Ato) #7

Very nice work. Thank you for sharing.