Re: Wireless Channel error model (fwd)

[Karunaharan Ratnam <karu@ece.neu.edu>]

> 
> i do not think this is correct, i believe the error model 'injects' errors
> in the LAN base on packets, bytes or bytes, independent if it is downlink
> or uplink, you should check the code for that.
> 
> --Javier
> -----------------------------------------
> COMET Group
> Columbia University, New York. 	


Javier:

I agree. But, the LAN is made up of point-to-multipoint links, and the
ErrorModel is installed seperately for downlink and uplink (see ns-lan.tcl).
Hence, the error injection is independant.

Karu.

PS: Is it okay if I post this reponse to ns mailing list?

>>On Sat, 8 Aug 1998, Karunaharan Ratnam wrote:
> 
> > Hi,
> > 
> > Question on error model (particularly for wireless channels).
> > 
> > Looking at the ns-lan.tcl, the ErrorModel is installed independantly
> > for forward link and reverse link.
> > In other words, when the ErrorModel uses Expo or TwoStateMarkov,
> > forward link can be in 
> > burst error state (fading) but the reverse link may not be experiencing
> > any fading, and transmitting error free.
> > 
> > Is it a correct model for wireless channel.
> > 
> > The links cannot be totally independant because,
> > * Fadding affects on both links are almost same (even if different
> > bands were used they are in similar spectrum).  
> > 
> > The links may not be totally dependant because,
> > * Radio at the hub (base station) may control power differently
> >   to handle the fading than the customer radio.
> > 
> > I'd like to see response on this (especially from radio engineers).
> > 
> > Karu.
> > 
> 
>