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RE: [ns] Error Model in Wireless Network
For modeling the transmission error over wireless channel, ns provides three propagation
models such as free-space, two-ray, and showdowing which compute the signal power
when a packet arrive at the receiver. Based on the left signal power, ns can decide a packet's
loss. For the detail of this large-scale fading effect, you may refer to "Wireless Communications"
written by Rappaport. Also search for the ns mail archive for small-scale fading models.
Ratis reported that he implemented the Ricean model for ns.
Ns also gives another mechanism to infuse errors over wireless channels based on some
analytical equation such as unifrom, multistate, and etc as like we do over wireline networks.
What you are asking is about the parameters related to these analytical equations to generate
errors.
Briefly, the rate indicates a probability that a packet, byte, or bit can be corrupted depending
on what unit you specified. The bandwidth is a parameter necessary for computing the byte
duration when the unit is time. I guess that this bandwidth should be the same as one specified
for physical wireless channels. For more information, please refer to errmodel.cc.
-jahn
-----Original Message-----
From: [email protected] [mailto:[email protected]]On Behalf
Of leandropereiramaciel
Sent: Saturday, May 26, 2001 12:03 AM
To: [email protected]
Subject: [ns] Error Model in Wireless Network
Hi, all,
I would like to know how to simulate a wireless network
where I can vary the following parameters:
> the transmission error of the channel - I'm using the
new function introduced in March, 2001. I understand
that i just need to adjust the "rate_" parameter (in
ErrorModel) to achieve the goal.
> the bandwidth of the channel - How I adjust the
bandwith? The right parameter to adjust is
"Phy/WirelessPhy set bandwidth"? If so, the "ErrorModel
set bandwidth" also has to have the same value?
> the size of the file being transmited - I need to
simulate a file being transmited, like a HTTP file. Is
there a protocol already done or i need to construct my
own?
Are my assumptions correct? Any suggestion is welcome.
Thanks...
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