Which should be the best signal strength acceptable for a cpe on 2.4 Ghz. (eg -55)? CCQ what %? ie the acceptable limits
This is a bit of a load questions as it will vary depending on the number of clients, speed of the packages, interference and what it is from, ap/cpe config, among a some of the variables
In practice I would recomend trying to keep siganals at -70 or better can go to -80 if there is no other 2.4 in the area
A good ccq is 80 or better but again if the load is low on the ap you can offen get a good connection down under 50
Notes: Some types of interference do not seem to lower the CCQ but your ping times go out the window we have seen this mostly on heavily loaded aps
generally a good signal is between -75 (bad) to -50 (good)
We made quite few measurements abour ATH chipsets.
Firstafally everything depends on noise backround.. This forms the estimation. In laboratory backround (when we are measuring sensitivity of cards) Is fine everything from -85dBm (noise level around -100dBm). Yes the speeds are lower, but everything works.
Real world is quite dependend on surrounding fullness of spectre and the best you can do is to make spectral analyse to find out what RF mess surrounds you. The level of this mess will make you new noise level and from that noise level you need at least 25dBs to get full thruput ability of device.
I mean, when the noise level is at peaks about -75dBm you will get full load by -50dBm. Atheros cards from 5414 and newer are quite linear up to -32dBm, then is starting distortion which are for OFDM lethal.
you are right but there is the noise factor that is a major player. this can really bring down a link. you will find latencies going high to the extent that the link is not usable. i have seen links with signal strength of -50 but with high latencies that traffic hardly pass through. So the answer could be good signal is -50 but performance will be dependant on the Noise levels in the environment