[ns] collisions in 802.11 or interference

[Nguyen Lan]

Imad Abdeljaouad wrote:
> Hi,
> I know it's in 802.11 MAC, but where exactly. And how do I know which
> packets are colliding and the "period of time" they collide?
> Thanks!
>   
Firstly, I recommend you ns manual. It is the document which you can 
find many fundamantal things inside.

the file is  ns_dir/mac/mac-802_11.cc and you have to read it in detail 
to find the way CSMA/CA is simulated. There are also some comments in 
the code that will  help you.

Cheers,

> On Wed, Nov 12, 2008 at 7:21 PM, Nguyen Lan <nguyentienlan at gmail.com> wrote:
>
>   
>> Imad Abdeljaouad wrote:
>>
>>     
>>> Hi Helber,
>>> Thanks for the prompt response. Actually, I am looking for the code in ns2
>>> (source code) where we can detect collisions. I want to simulate
>>> interference, so I need to get the packets that were received at the same
>>> time on some node. I know interference happens on the physical layer, but
>>> I
>>> think it would be much more easier to implement it on the MAC in ns2. So I
>>> am actually looking the source code part that says here is another packet
>>> being transmitted while receiving another packet ( which is collision if
>>> both packets are meant for the same receiver, and interference if both
>>> packets belong to the same (or an adjacent) channel.
>>>
>>>
>>>       
>> I think the implementation of 802.11 MAC is exactly the place you should
>> look into.
>>
>> Cheers,
>> Nguyen.
>>
>>  Can you help with that ?
>>     
>>> cheers,
>>>
>>> On Tue, Nov 11, 2008 at 8:35 PM, Helber Wagner <wagnerfbm at yahoo.com.br
>>>       
>>>> wrote:
>>>>         
>>>
>>>       
>>>>  Hi, Imad.
>>>>
>>>>  As far as I understood your question, you should analyze the trace file
>>>> generated
>>>> by your simulations.
>>>>
>>>>  If the MAC trace is enabled in your .tcl file, it will be a row like "D
>>>> ... COL ..."
>>>> indicating the time, the node, the packet and other information about a
>>>> collision
>>>> that has been happened.
>>>>
>>>>  Finally, a simple perl/awk script can retrieve this information from the
>>>> trace file.
>>>>
>>>>  You can find more about mac trace in NS2 over the Internet.
>>>>
>>>>  Good luck.
>>>>
>>>> ---
>>>> Helber Wagner da Silva
>>>> Federal University of Cear��� - Brazil
>>>> URL: www.great.ufc.br/~helberhws <http://www.great.ufc.br/%7Ehelberhws><
>>>> http://www.great.ufc.br/%7Ehelberhws>
>>>>
>>>>
>>>>
>>>> ------------------------------
>>>> *De:* Imad Abdeljaouad <abdeljaouad at gmail.com>
>>>> *Para:* "ns-users at isi.edu" <ns-users at ISI.EDU>
>>>> *Enviadas:* Ter���a-feira, 11 de Novembro de 2008 23:17:46
>>>> *Assunto:* [ns] collisions in 802.11 or interference
>>>>
>>>>
>>>> Hello there,
>>>> I am looking for the code where collisions in 802.11 occur so that I know
>>>> which packet(s) collided and for how long they collided? this is a step
>>>> in
>>>> trying to implement interference!
>>>> thank you!
>>>>
>>>> --
>>>> best regards,
>>>> ________________________
>>>> Imad Abdeljaouad
>>>>
>>>> ------------------------------
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>>>>
>>>>
>>>>         
>>>
>>>
>>>
>>>       
>>     
>
>
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