[e2e] Overly Overlay; Peer to peer is commonplace
Nitin H Vaidya
nhv at godel.crhc.uiuc.edu
Wed Jan 2 14:10:42 PST 2002
The objections you raise are reasonable.
I should have hedged a bit when I earlier stated that
graph models for radio networks are
"fine". I did not mean to imply that they are a perfect model, but only
that they may suffice for certain purposes. For instance, for routing
protocols that rely on "hop-by-hop" packet forwarding,
graph models seem adequate. Should we be looking at other kinds of
Given that graphs are an approximation of reality, they cannot be
expected to serve for all purposes.
On Wed, 2 Jan 2002, David P. Reed wrote:
. >>Signals do not interfere with each other in the physical medium - they are
. >>superposed on each other (a reversible process). With space-time coding,
. >>for one interesting current example, they can in many cases be completely
. >>separated again. (in fact, in a band-limited and space-bounded diffusive
. >>medium, it's been shown that as the number of transmitter reciever pairs
. >>increases with N, the communications capacity of the channel increases
. >>linearly with N. The *opposite* of what you'd expect if signals interfere
. >>and diffusion/multipath could be viewed as as noise).
Yes, you are right that channel capacity can grow with N
Does that necessarily mean that bit rates of different "links"
are independent? I did not think so, but I could be
mistaken, particularly, considering that I did not know that the
capacity can grow *linearly* with N without imposing some constraints.
Does this result require some assumptions about the channel, or receivers?
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