How to get a mobile node's current position

[Leyond]

Hello,everyone:
      I want to simulate a wireless scenario with two access points and a mobile node. This mobile node moves randomly, the question is how to calculate it's position like(x=?,y=?,z=0) at any given time. It could be better if you could give me an example. Of course, any suggestion is welcome.
     Regards.
     Liceven

[Leyond]

Hi, today I find we could use tcl script to get a node's position.
codes like this:
      set n1 [$ns node]
     $ns set X_ 15.0
     $ns set Y_ 15.0
     $ns set Z_ 0.0
 ...
     set x_pos [$n1 set X_]
...
   'set x_pos [$n1 set X_]' this script could be used to get the x value of n1's starting position. but it could not record the coordinate dynamically. So, If I want to implement this dynamic function, what should i do? thanks very much.
Liceven

Liceven wrote:

Hello,everyone:
      I want to simulate a wireless scenario with two access points and a mobile node. This mobile node moves randomly, the question is how to calculate it's position like(x=?,y=?,z=0) at any given time. It could be better if you could give me an example. Of course, any suggestion is welcome.
     Regards.
     Liceven

[Jalaluddin Qureshi]

Dear Liceven,

While I cant give you step-by-step instruction on how to solve your problem. But here is the idea. If you were to go to ns-allinone2.xx/ns2.xx/mobile/antenna.cc file you will see the function:

Antenna::Antenna()
{
  X_ = 0; Y_= 0; Z_= 0;
  bind("X_", &X_);
  bind("Y_", &Y_);
  bind("Z_", &Z_);
}

Basically this constructors binds the X_ variable in the TCL file with the X_ in the C++ file. If you were to add say:

cout << "X position" << X_ << endl;
cout << "Y position" << Y_ << endl;
cout << "Z position" << Z_ << endl;

after   bind("Z_", &Z_); but before }. And then run the "make clean" and "make" command at the Linux command terminal in the ns-allinone2.xx/ns2.xx/ prompt area. Once thats done, if you were to run your .tcl file, you will see an output, which specifies the position of your node in X, Y, Z coordinate.

The glitch with this approach is that it shows you the coordinates for time 0.0, mean just at the start of the simulation.

For your problem, YOU need to find the .cc file which is responsible for changing the X, Y, Z coordinates. Once you locate that .cc file, then locate the function which is changing the value of X, Y, Z, and then you can add the above cout lines at the end of that function.

This way, when you run the simulation, you will get live time output of the X, Y, Z coordinates. If you know C++ half-decent, then I think it will not take you more than 2-5 hours to locate the function and find the solution of your problem.

PLEASE ONCE YOU SOLVE YOUR PROBLEM, DO SHARE YOUR SOLUTION WITH OTHERS ON THE NS MAILING LIST.

Kind Regards
Jalaluddin Qureshi

Research Student @ CeMNet, SCE
Nanayang Technological University
N4-B2c-06, Nanyang Avenue
Singapore 639798
http://www.cemnet.ntu.edu.sg

--Forwarded Message Attachment--
From: feixianyexin@...
To: ns-users@...
Date: Wed, 23 Jul 2008 00:00:36 -0700
Subject: [ns] How to get a mobile node's current position


Hello,everyone:
      I want to simulate a wireless scenario with two access points and a
mobile node. This mobile node moves randomly, the question is how to
calculate it's position like(x=?,y=?,z=0) at any given time. It could be
better if you could give me an example. Of course, any suggestion is
welcome.
     Regards.
     Liceven
--
View this message in context: http://www.nabble.com/How-to-get-a-mobile-node%27s-current-position-tp18604950p18604950.html
Sent from the ns-users mailing list archive at Nabble.com.



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[Leyond]

Dear Jalaluddin,
 Thanks very much for your great suggestion. But it is difficult for me to modify some cc file to reach the target. And I think I should spend more time to get understood how TCL communicates with C++ class.
 Just as the same as what I said before, there is a way to get a mobile node’s position. The TCL script codes are shown as bellow:
set node(1) [$ns node]
     $ node(1) set X_ 15.0
     $ node(1)set Y_ 15.0
     $ node(1)set Z_ 0.0
 ...
for {set i 0} {$i < $val(nn)} {incr i} {
   $ns initial_node_pos $node($i) 60
}
….
     the script ‘set x_pos [$node(1) set X_]’ could be used to get the x value of the mobile node at the time 0.0.
So, I am wondering may I write a proc used to record this x value every 0.5 second. The tcl codes are:
proc record {} {
  global filepr d pt l lambda gt gr pi node(1) #here I just want to record node 1
   set ns [Simulator instance]
   set time 0.5;# record 0.5 second
   set pr 0.0
   set m [expr (1 /(4 * $pi * $d))]
   set pr [expr ($pt * $gr * $gt * $m * $m / 1)]
   set d [expr ($d+10)]
  # set xp [$n1 set X_]
   set now [$ns now]
   set node_x [$node(1) set X_]
   set node_y [$node(1) set Y_]
   puts $filepr "$now\t$pr\t$node_x\t$node_y"
   $ns at [expr $now + $time] "record"
}
$ns at 1.0 "record"

But when I run this script, there is an error” node(1), no such variable”. Today I happen to find the solution about this problem in the internet:
Change ‘global node(1)’ to ‘global node’. Pay attention that node($i) is an array[I still havn't found the reason yet]. And this function 'record' will help me to finish the job[record  a mobile node’s position (x,y) every 0.5 second]. The result is like this:
....
4 1.4748094279189353e-07 550 500
4.5 1.2392495887374392e-07 475.2091266690191 433.51922370579473
5 1.0559286436579362e-07 475.2091266690191 433.51922370579473
....

And, I think I will think over your idea when i get enough knowledge about NS.
Thanks very much again.
Best wishes.
Liceven

Jalaluddin Qureshi wrote:

Dear Liceven,

While I cant give you step-by-step instruction on how to solve your problem. But here is the idea. If you were to go to ns-allinone2.xx/ns2.xx/mobile/antenna.cc file you will see the function:

Antenna::Antenna()
{
  X_ = 0; Y_= 0; Z_= 0;
  bind("X_", &X_);
  bind("Y_", &Y_);
  bind("Z_", &Z_);
}

Basically this constructors binds the X_ variable in the TCL file with the X_ in the C++ file. If you were to add say:

cout << "X position" << X_ << endl;
cout << "Y position" << Y_ << endl;
cout << "Z position" << Z_ << endl;

after   bind("Z_", &Z_); but before }. And then run the "make clean" and "make" command at the Linux command terminal in the ns-allinone2.xx/ns2.xx/ prompt area. Once thats done, if you were to run your .tcl file, you will see an output, which specifies the position of your node in X, Y, Z coordinate.

The glitch with this approach is that it shows you the coordinates for time 0.0, mean just at the start of the simulation.

For your problem, YOU need to find the .cc file which is responsible for changing the X, Y, Z coordinates. Once you locate that .cc file, then locate the function which is changing the value of X, Y, Z, and then you can add the above cout lines at the end of that function.

This way, when you run the simulation, you will get live time output of the X, Y, Z coordinates. If you know C++ half-decent, then I think it will not take you more than 2-5 hours to locate the function and find the solution of your problem.

PLEASE ONCE YOU SOLVE YOUR PROBLEM, DO SHARE YOUR SOLUTION WITH OTHERS ON THE NS MAILING LIST.

Kind Regards
Jalaluddin Qureshi

Research Student @ CeMNet, SCE
Nanayang Technological University
N4-B2c-06, Nanyang Avenue
Singapore 639798
http://www.cemnet.ntu.edu.sg

--Forwarded Message Attachment--
From: [e-mail]
To: [e-mail]
Date: Wed, 23 Jul 2008 00:00:36 -0700
Subject: [ns] How to get a mobile node's current position


Hello,everyone:
      I want to simulate a wireless scenario with two access points and a
mobile node. This mobile node moves randomly, the question is how to
calculate it's position like(x=?,y=?,z=0) at any given time. It could be
better if you could give me an example. Of course, any suggestion is
welcome.
     Regards.
     Liceven
--
View this message in context: http://www.nabble.com/How-to-get-a-mobile-node%27s-current-position-tp18604950p18604950.html
Sent from the ns-users mailing list archive at Nabble.com.



_________________________________________________________________
Check out Barclays Premier League exclusive video clips here!
http://fc.sg.msn.com/index.aspx