[Battlemesh] Why does .11ax increase the guard interval?

[Juliusz Chroboczek]

> Does anyone understand why .11ax increases the guard interval?

I found the answer here:

  https://mentor.ieee.org/802.11/dcn/15/11-15-0099-04-00ax-payload-symbol-size-for-11ax.pptx

It turns out that .11ax aims to improve behaviour in non-line-of-sight
outdoors situations, where multipath issues are more severe than in the
usual cases (indoors nLOS, outdoors LOS).  To that, they:

  - increase the symbol time (and therefore the size of the FFT);
  - increase the guard interval.

I'm not sure what problems outdoors nLOS is supposed to solve, but if the
problem does exist, it makes sense to relax the timing parameters.

-- Juliusz