What are the pros and cons of Short vs Long GI? I know the ePMP 4k APs come with Long GI as the default and that I can get more bandwidth with Short GI, but what is the drawback?
In my tests with a single SM and a perfect MCS11 link (over 50db SNR) I saw around a 5-6% aggregate increase in throughput on Link Tests using Short over Long GI.
What circumstances would one recommend Long GI over Short GI? (interference, fresnel blockage. etc.)
Are there circumstances where the Long GI would actually give more performance vs Short GI?
The Guard Interval is a little delay between the wireless symbols, to make sure that your own transmissions don’t ‘echo’ on top of each other. So (if you think about it as sound) it’s a small delay between each word, so that the echo from the 1st word has time to dissipate, and not still be echoing when the 2nd word is trying to be heard.
As Eric says, in practicality we never see it be a problem, and Short GI is virtually always better. But (in theory) there may be some location, some situation, where there is destructive multipath and maybe a Longer Guard Interval might (in theory?) help.