[ns] Mac protocol modification in 802.11n

[nishil dahin]

Hi guys,

I want to try out a new MAC protocol in 802.11 g or 802.11 n;
 I am thinking about changing the back-off mechanism to implement the
protocol
Is this possible?

If so, kindly tell me the files I may have to modify;

Thanks in advance

Nishil

[ns] Wimax implementation in ns2

[nishil dahin]

Hi guys,

I wanted to know which all are the main files related to wimax
implementation in ns2.

 Like for wifi - ieee 802.11, it is mac-802_11.cc, .h and mac-timers.cc, .h;
correspondingly, which files are for 802.16 (wimax) ?

Nihad S.

[ns] finding consecutive collisions

[nishil dahin]

hello,

I was trying to find the number of consecutive collisions in wireless
network with the following logic:

int collision = 0;
while (rx_state_ == MAC_COLL)
{
collision++;
}
return collision;

the problem is I think the above code results in infinite loop;
Any help will be appreciated.

Nihad S.

[ns] NS@ debugging

[nishil dahin]

Hi guys,

This may sound trivial; but I wanted to know if NS2 has any default
debugger that can debug both tcl and the 'backend' .cc files?

Thanks in advance

[ns] finding consecutive collisions

[nishil dahin]

hi guys,
 i wanted to know how to find whether collision that takes
place in wireless network is consecutive or not; any ideas will be helpful

[ns] Average number of idle slots

[nishil dahin]

Hello all,

How do you find the average number of idle slots of a node?

Thanks in advance,
Nihad S.

[ns] period controlled MAC

[nishil dahin]

I am working on a masters [paper][1] where I am trying to change the random
waiting time for MAC wireless networks to a Period-controlled MAC for
higher performance.  There are a couple of existing c++ files that need
alterations to change them from random to periodic.  I have narrowed it
down to the following function:

void
BackoffTimer::start(int cw, int idle, double difs)
{
 Scheduler s = Scheduler::instance();

 assert(busy_ == 0);

 busy_ = 1;
 paused_ = 0;
 stime = s.clock();

 rtime = (Random::random() % cw) * mac-phymib_.getSlotTime();
#ifdef USE_SLOT_TIME
 ROUND_TIME();
#endif
 difs_wait = difs;

 if(idle == 0)
  paused_ = 1;
 else {
  assert(rtime + difs_wait = 0.0);
  s.schedule(this, intr, rtime + difs_wait);
 }
}

I would appreciate it if anyone could help me alter this method to change
the random calculation to periodic.  Thanks.

I will explain the proposed protocol in terms of a simple scenario:
consider 2 transmitting nodes experiencing a collision in a network; after
they each have waited a random amount of time; say x and y, (implying they
both have different backoff periods) if we imply periodic backoff from
there on, their backoffs will be x+a, y+a which goes on and will never be
equal; preventing them from ever colliding with each other again.

Also, the period of the backoff is same for all the nodes in the network
('a' in the above example), and any change that has to be done with this
'a' period will also affect with all the nodes in the network.

rtime in the program denotes the remaining time of backoff,
cw denotes the contention window value and
difs denotes the 802.11 dcf inter frame space

Any advice or suggestion will be much appreciated.

[ns] hidden terminals in wireless

[nishil dahin]

hi guys.

where do we define whether the wireless network is complex (with hidden
terminals) or simple (no hidden terminals)? - in the .tcl file or the
backend .cc file ?

thanks

[ns] Periodic backoff in 802.11

[nishil dahin]

hello...

i am trying to implement a periodic backoff scenario instead of random type
currently used in IEEE 802.11 DCF; This is for my project in ns2 based on
an IEEE 2011 paper.
My query is about the correctness of method of my implementation: change
the mh_backoff function present in the mac_timer.cc file (I am changing the
backoff timing scenario of the wireless protocol); Is it the right way? or
am I missing something?

Any advice or suggestions would be appreciated.

Nishil A.