[ns] RXThresh values!!

2012-08-04 Thread wben-jab


Dear all,
Has anyone an idea about the different corresponding values of the  
parameter  RXThresh, when varying the distances. Or when I could find  
these values?

set RXThresh 1.76149e-10 ;#compute with threshold.cc for distance 300m


Thanks.



Re: [ns] Properly drop packet

2012-08-04 Thread Giorgos Karanikas


Thanks for the help. After all I managed to do what I wanted. I created a new
type of queue that I use to do the job of a firewall. At least it works :P
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Re: [ns] RXThresh values!!

2012-08-04 Thread Saravanan Kandasamy

Dear Wben,

I presume you like to know the relationship between distance vs RXthresh ?

It might not be that straight forward as it depends on which multipath
propagation you like to use.

Assume this topology
-Two nodes (T and R),  node T would be transmitting to node R placed x
meter away.

You need to know,
1. Frequency you like to operate
2. Which multipath propagation you like to use.
3. Transmit power
4. Gain of antenna
5. Height of the transmitter and receiver

Assume Two-Ray Ground Reflection Model

Method
1. Using the frequency, calculate the cut off distance (m) using
(4*PI*ht*hr)/lambda where lambda is c/freq, ht and hr is the height of
T and R.
2. If the T-R separation is below the cut off distance, use Friis
Equation, if it is above the cut off distance use two-ray reflection
model.
3. The Pr is the RXThresh you need to set in your simulation varying
the distance from the Friis/Two-ray ground reflection equation which
you can easily get from the internet.

So when you get 300m using 1.76149e-10W RxThresh most likely you used
two-ray ground reflection model operating at 2.4GHz frequency.

Good luck.

rgds
Saravanan K


On Sat, Aug 4, 2012 at 2:18 PM,  wben-...@labri.fr wrote:


 Dear all,
 Has anyone an idea about the different corresponding values of the
 parameter  RXThresh, when varying the distances. Or when I could find
 these values?

 set RXThresh 1.76149e-10 ;#compute with threshold.cc for distance 300m


 Thanks.




[ns] node Id from queue monitor

2012-08-04 Thread Dejene B.

Hello all,

Does anyone know how to get node Id from TCL side?
It is possible to hold node ID when it is created since ns-2 starts
assigning node from 0, but as I have several nodes I want to access at some
point during simulation.
There is something like srcId_ and dstId_ in Queue-monitor, are they the
same as source and destination IDs, if so how can I access from TCL side
 like the following.
set qeuemon [$ns monitor-queue $n1 $n2  ]

thanks,


-- 
*Dejene Boru*
*.
*
Graduate Student-Telecom Eng
University of Trento
Via  Brennero 150
Trento, Italy
dejeneboru.oljir...@unitn.it
djz...@gmail.com
0039-388-998-1919

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