[ns] Fading and interference effect in NS2 802.11b

[Jee J.Z.]

Oh, so you mean that NS2 only counts in the path loss model, right? Do you
know which path loss model NS2 is using? Free space path loss or other
empirical models? What if the distance is between 250m and 550m then?

On the other hand, does NS2 dynamically change 802.11b datarate according to
the current channel conditions?

Cheers,
Jee


----- Original Message ----- 
From: "Joshua Robinson" <jpr at rice.edu>
To: "Jee J.Z." <jz105 at york.ac.uk>
Sent: Tuesday, February 24, 2004 4:07 PM
Subject: Re: [ns] Fading and interference effect in NS2 802.11b


> the simple fading models means that if two nodes are within a certain
> distance (250m) they will always receive packets from each other.  If the
> nodes are within another range, the carrier sense range (550m), then they
> will always be able to sense carrier.  And if the nodes are farther apart
> than this, they will not hear anything from each other.
>
> this webpage will give you more information about a more realistic fading
> model.  and give a link to some code
> http://www.ece.rice.edu/networks/software/OAR/OAR.html
>
> On Tue, 24 Feb 2004, Jee J.Z. wrote:
>
> >
> > Hi Joshua,
> >
> > Thank you very much for you quick reply. So could you give me more
> > information on how the "very simple fading model" is working? If you can
> > point me to a more realistic model, that would be great!
> >
> > Regards,
> > Jee
> >
> >
> > ----- Original Message -----
> > From: "Joshua Robinson" <jpr at rice.edu>
> > To: "Jee J.Z." <jz105 at york.ac.uk>
> > Sent: Tuesday, February 24, 2004 3:20 PM
> > Subject: Re: [ns] Fading and interference effect in NS2 802.11b
> >
> >
> > > ns has a very simple fading model with no dynamic fading.  The MAC
will
> > > not ACK a packet with errors, because really, the MAC wouldn't even
know
> > > if it received a data packet or not.  If you want more info on a more
> > > realistic channel fading model for NS, let me know and I can't point
you
> > > to a good place.
> > >
> > > On Tue, 24 Feb 2004, Jee J.Z. wrote:
> > >
> > > >
> > > > Hi all,
> > > >
> > > > Could anybody give me some clue that whether NS2
integrates/considers
> > > > channel fading and interference effect in the 802.11b model?
> > > >
> > > > Another question on 802.11 is: when there are bit errors in a
received
> > > > frame, what will the receiving node do? Just discards the frame and
does
> > not
> > > > send the ACK? This is not a NS2 question, but I hope somebody can
> > provide me
> > > > some information. Thanks a lot in advance!
> > > >
> > > > Jee
> > > >
> > > >
> > >
> >
> >
>