Subject: Re: Why the (300m x 1500m area) is used in most simulations ?

From: Hollos Daniel <[email-masked]>
Date: Mon, 3 Sep 2001 13:43:05 +0200 (CEST)

> Models used for evaulating cellular handoff schemes can't be used in 
> ad hoc networks because they tend to be discretized into cell-to-cell
> transitions, while our models require an exact location in order to
> determine the signal and interference at a receiver.
> 
> Again, I hope this answers your question...
> 
> Yih-Chun
> 
Hi,

  just an idea: Isn't it possible to extend the cellular prediction
models to the MANET scenarios? E.g. if you change the scale of cells to
very
small, to the size of your grid, you can use it for determining the exact
(x,y) coordinates of the terminals. The question is, when making such
a down-scale, the result would be realistic or not. Moreover, is at
least the cell-handover probablility the same to the MANET terminal 
grid-changing probablilty to all directions?

Yours,

****************** Daniel Hollos *************************
*                                                        *
* Technical University of Berlin                         *
* Faculty of Electrical Engineering and Computer Science *
* Telecommunication Networks Group                       *
* Phone: +49 30 31479677 (Office)                        *
*        +49 16095401825 (Cell/Mobile)                   *
*                                                        *
**********************************************************

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From: Yih-Chun Hu <[email-masked]>
Date: Mon, 3 Sep 2001 10:03:10 -0400 (EDT)

>grid-changing probablilty to all directions?

We don't have a grid (except to the extent that doubles are quantized),
but you'd need a very large-scale cellular model in order to have a very
small-scale manet model. For example, if a cellular cell is spaced 1km
apart (pretty close in my understanding), and we want our manet "cells" to
be spaced 1m apart (pretty far I think), then we're already imposing a
1000:1 "downsizing". Supposing we want a space with the same area as a
1500m x 300m scenario, for reasons that I've described earlier, we need a
cellular network model that covers 450,000km^2. By comparison, Germany's
total area is 356,910km^2.

Also, to emulate the same speed as cellular users, we would need to speed
up the scenario by the same factor as we downsize it; for example, to run
a 900 second scenario, we would need a 250 hour cellular trace.

Hope this helps,
Yih-Chun