-----Original Message----- From: Starlink [mailto:starlink-boun...@lists.bufferbloat.net] On Behalf Of Leonard Kleinrock Sent: Monday, August 2, 2021 5:38 PM To: David Lang Cc: starl...@lists.bufferbloat.net; Make-Wifi-fast; Bob McMahon; Cake List; co...@lists.bufferbloat.net; cerowrt-devel; bloat Subject: Re: [Starlink] [Cake] [Make-wifi-fast] [Cerowrt-devel] Due Aug 2: Internet Quality workshop CFP for the internet architecture board
These cases are what my student, Fouad Tobagi and I called the Hidden Terminal Problem (with the Busy Tone solution) back in 1975. [RR] Also known as the "hidden node" problem! Len > On Aug 2, 2021, at 4:16 PM, David Lang <da...@lang.hm> wrote: > > If you are going to setup a test environment for wifi, you need to include the ability to make a fe cases that only happen with RF, not with wired networks and are commonly overlooked > > 1. station A can hear station B and C but they cannot hear each other [RR] Lots of reasons for that in the wireless world of mobility. > 2. station A can hear station B but station B cannot hear station A [RR] This is largely due to link imbalance. In TDD systems like Wi-Fi, time variability of the RF channels is also an issue that is dealt with by having turn around times that are much less than the "(de-)coherence time" of the channel. Link imbalance is largely due to differences in tx power and rx front end noise figure. Smart antenna technology makes this a bit more complicated, but the essentials are still the same. 3. station A can hear that station B is transmitting, but not with a strong enough signal to decode the signal (yes in theory you can work around interference, but in practice interference is still a real thing) [RR] Yes, energy can be detected at levels that are insufficient for decoding. That said, if you can't decode the signal, you generally cannot know who sent it :^))) > > David Lang > _______________________________________________ Starlink mailing list starl...@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/starlink _______________________________________________ Cerowrt-devel mailing list Cerowrt-devel@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/cerowrt-devel
