[e2e] Collaboration on Future Internet Architectures
Jon Crowcroft
Jon.Crowcroft at cl.cam.ac.uk
Fri May 11 06:06:11 PDT 2007
In missive <Pine.LNX.4.44.0705041458330.24385-100000 at gato.kotovnik.com>, Vadim Antonov typed:
>>People who claim that increasing the density of raido nodes will increase
>>the per-node bandwidth (or at least leave it unchanged) are simply not
>>good with arithmetic.
conversely, at geometry
>>Let's look at a plane with some distribution of radio nodes on it, with
>>per-node characteristic bandwidth B, achieved at signal/noise ration SN0.
try a volume, not a plane. the number of alternate paths the the volume
goes up faster, and one can use lots of disperity tricks (path, code etc)
to make the alternates only have epsilon interference - if you then alternate
dynamic power over a short haul hop to spread the signal to a neighbourhood,
with dynamic coding for longer haul to get the message to the next neighbourhood,
you get capacity within epsilon*Nhops of N - conjecture: a sequence of
"knights moves" of 1 hop up, 2 hops forward can tile a volume in a systematic way and use the
scheme above (due to Tse) in a very easy to self organised fashion...
Imagine a field full of children all sitting in groups, and at the middle of each group is a teacher.
You can ask the teacher a question by putting up your hand, and each teacher can listen and answer one child at
a time. If two groups of children are too close together, then one child asking a question, or one teacher
answering may drown out the other group. We try and have enough teachers so that if all the children who want
to ask a question at the same time do so, then there are enough teachers to answer. If the teacher you are
asking is busy, you might go from the edge of the group you are in, nearer to the edge of another group and try
and ask their teacher.
But imagine you can't be bothered to move, but you notice that the teacher nearest is busy, and a teacher
further is not busy. What if you shout your question? What if the teacher nearby can still manage to lisen to
the nearby child, even while one or two of you shout to a further teacher?
An interesting question to ask is: how many more questions can the teachers and groups of children answer if
the teachers can deal with sorting out different people speaking?
so now have kids either sit or stand to ask a question, and speak in a low or high squeeky voice, and have
teachers sit or stand, and choose to listen to high or low grumbly voices...
j.
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