Agreed that incentives are non trivial. I found this article about bike share redistribution interesting:
New York's bike share system pays rider to make it run better <http://www.slate.com/blogs/moneybox/2017/02/09/new_york_s_citi_bike_pays_riders_to_make_it_run_better.html> Bob On Thu, Aug 30, 2018 at 1:36 PM bkil <bkil.hu...@gmail.com> wrote: > Yes, I've read that part in the past. These are very good rules of > thumb, but there are many inefficiencies to cope with. > > Note that not all wireless users are "rude" on purpose. It's just that > if you want to keep in touch with your relatives in the nearby town, > you use the minimal needed power for the given circumstances that > happens to be a large amount (point to point). > > 1a. > Let's focus on a point to point link first. Omni antennas would > trivially interfere with our own neighborhood as well while working a > long link. However, because not everyone has roof access, space for a > large aerial or money for an expensive one, using an omni would be > considered a local optimum for many. > > 1b. > Let's assume that we are a good citizen using more expensive highly > directional antennae and we live at the perimeter. Considering that > the reception angle of the most practical ones should be 10-20 > degrees, this probably easily illuminates the perimeter of the > neighboring town. That wouldn't be deadly interference from that > distance, but it means that it's not scalable in the sense that not > everyone living at the perimeter could communicate with their > respective relative in the neighboring town. It would need a high > level of sophistication to achieve that. It would be much more > efficient and cost effective if these people cooperated and pooled in > resources to build only a handful of well-placed high power > transcievers that they digitally shared with each other using low > power and inexpensive last mile access technologies. But as the old > saying goes, "The common horse is worst shod." So it is cleanest if we > simply pay for equipment and maintenance, and a new telco is born. > Then as competition intensifies, the spectrum gets clogged up, etc. > > 1c > If we aren't fortunate enough to live at the perimeter, we need to > cooperate with hops towards the perimeter. It is energetically the > most efficient to have directional links between each of them, but > that requires 2-3 antennae at each node. The ones at the perimeter > definitely need at least two. For one who lives at the perimeter and > only communicates with the neighboring town, it is a local optimum to > not purchase and operate two sets of antennae, cables, radios and > other tools. Without incentives, taking this to the extreme creates a > disconnected ring of perimeter around the town who point outwards. So > in worst case, ones in the middle would again need to up their power > again to work the distance. > > 2. > To achieve hop optimization, have we reached a level of social > sophistication and digital literacy where we can mesh with everything > and anyone in sight? I feel that to be a stretch, but let's pretend > that we have. Now the "feasible" part is still problematic. > Let's stick with the above scenario of inter-town links or sparsely > populated areas. If there is nobody to mesh with, we need to > artificially deploy and maintain intermediate nodes for this purpose. > Who will pay for this? If nobody, it is not feasible. See above point. > The local optimum of each user is to not deploy intermediate nodes, > and we have reached the tragedy of the commons again. > > And we didn't even consider "rude" users analogue to an uninvited > guest who gobbles all your snacks when dropping by. These are only a > minority, but they take plenty. Though UWB wasn't there yet in 1994, > it's feasible today. Just imagine if a school deployed a 1GHz UWB > transciever on UHF to stream their backups or research data all day > over the air because it is less expensive (free) compared to cables. > It would not be feasible to peer with any intermediate hop because > nobody has such expensive and advanced hardware, so they'd happily > operate a point to point link to the nearby town (or partner > institution?). That would definitely spoil the fun for many along the > route and no amount of LBT can fix that. Also they could have decide > to use >100GHz instead, but there is no incentive if the whole > spectrum is free, as higher frequencies propagate worse and equipment > costs more. > > So all in all, without incentives, system spectral efficiency doesn't > come naturally - you have to work for it. Hard. > I'm not saying that we should give up, but it takes much more than a > few sentences to come up with rules that really work in real life > situations when scaled up. There are pro and contra in many methods of > spectrum allocations, no doubt about that, but I don't feel that there > exists one clear "best" method that we are purposefully neglecting. > > Of course at the same time, scalable unregulated alternatives do > exist, but we were talking radio above: > https://en.wikipedia.org/wiki/RONJA > https://en.wikipedia.org/wiki/Modulated_ultrasound > https://en.wikipedia.org/wiki/Sneakernet > > On Thu, Aug 30, 2018 at 9:17 PM Bob McMahon <bob.mcma...@broadcom.com> > wrote: > > > > Minimizing power is rule #2 per Paul Banan. > > > > SOME KINDERGARTEN RULES (written in 1994) > > > > To take the fullest advantage of our new technology with its sharing > > of a common resource requires that our smart transmitters and > > receivers cooperate. This may sound complicated, but the rules to make > > maximum effective use of the shared band are simple -- primarily a > > matter of common decency in sharing resources. The rules are somewhat > > similar to those you learned in kindergarten, assuming you lived in a > > tough neighborhood. > > > > Rule #1. Keep away from the big bullies in the playground. (Avoid the > > strongest signals.) > > > > Rule #2. Share your toys. (Minimize your transmitted power. Use the > > shortest hop distances feasible. Minimize average power density per > > Hertz.) > > > > Rule #3. If you have nothing to say, keep quiet. > > > > Rule #4. Don't pick on the big kids. (Don't step on strong signals. > > You're going to get clobbered.) > > > > Rule #5. If you feel you absolutely must beat up somebody, be sure to > > pick someone smaller than yourself. (Now this is a less obvious one, > > as weak signals represent far away transmissions; so your signals will > > likely be attenuated the same amount in the reverse direction and > > probably not cause significant interference.) > > > > Rule #6. Don't get too close to your neighbor. Even the weakest > > signals are very strong when they are shouted in your ear. > > > > Rule #7. Lastly, don't be a cry baby. (If you insist on using obsolete > > technology that is highly sensitive to interfering signals, don't > > expect much sympathy when you complain about interfering signals in a > > shared band.) > > > > Bob > > > > > > On Thu, Aug 30, 2018 at 12:12 PM bkil <bkil.hu...@gmail.com> wrote: > >> > >> Full-duplex still needs some work, but there is definite progress: > >> http://www.ti.rwth-aachen.de/~taghizadehmotlagh/FullDuplex_Survey.pdf > >> > https://www.microsoft.com/en-us/research/wp-content/uploads/2016/02/TR-1.pdf > >> https://sing.stanford.edu/fullduplex/ > >> > https://spectrum.ieee.org/tech-talk/telecom/wireless/new-full-duplex-radio-chip-transmits-and-receives-wireless-signals-at-once > >> http://fullduplex.rice.edu/research/ > >> > >> On Mon, Aug 27, 2018 at 9:46 PM Jonathan Morton <chromati...@gmail.com> > wrote: > >>> > >>> > On 27 Aug, 2018, at 10:11 pm, Bob McMahon <bob.mcma...@broadcom.com> > wrote: > >>> > > >>> > I guess my question is can a WiFi transmitting device rely on > primarily energy detect and mostly ignore the EDCA probability game and > rather search for (or predict) unused spectrum per a time interval such > that its digital signal has enough power per its observed SNR? Then > detect "collisions" (or, "superposition cases" per the RX not having > sufficient SINR) via inserting silent gaps in its TX used to sample ED, > i.e. run energy detect throughout the entire transmission? Or better, no > silent gaps, rather detect if there is superimposed energy on it's own TX > and predict a collision (i.e. RX probably couldn't decode its signal) > occurred? If doable, this seems simpler than having to realize centralized > (or even distributed) media access algorithms a la, TDM, EDCA with ED, > token buses, token rings, etc. and not require media access coordination by > things like APs. > >>> > >>> The software might be simpler, but the hardware would need to be > overspecified to the point of making it unreasonably expensive for consumer > devices. > >>> > >>> Radio hardware generally has a significant TX/RX turnaround time, > required for the RX deafening circuits to disengage. Without those > deafening circuits, the receivers would be damaged by the comparatively > vast TX power in the antenna. > >>> > >>> So in practice, it's easier to measure SNR at the receiver, or > indirectly by observing packet loss by dint of missing acknowledgements > returned to the transmitter. > >>> > >>> - Jonathan Morton > >>> > >>> _______________________________________________ > >>> Make-wifi-fast mailing list > >>> make-wifi-f...@lists.bufferbloat.net > >>> https://lists.bufferbloat.net/listinfo/make-wifi-fast > >> > >> _______________________________________________ > >> Make-wifi-fast mailing list > >> make-wifi-f...@lists.bufferbloat.net > >> https://lists.bufferbloat.net/listinfo/make-wifi-fast >
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