[Ns-developers] Reproducing Broch AODV Performance Numbers

[Kevin Peters]

Are there any further thoughts on this?  Is a low packet delivery expected
with these simulations in ns-3 even with such a low data rate?

Thanks,
Kevin

On Thu, Apr 15, 2010 at 2:41 PM, Kevin Peters <kevjay at gmail.com> wrote:

> On Thu, Apr 15, 2010 at 4:44 AM, Nicola Baldo <nbaldo at cttc.es> wrote:
>
>>  Is is possible to make a simple change to ns-3 such that it
>>> receives based on received signal strength like ns-2 in order to
>>> rule this out or in?  Just a temporary toggle to check if this
>>> could explain the differences in performance?
>>>
>>
>> As a quick hack, you can modify YansWifiPhy::EndReceive as follows:
>>
>> - if (m_random.GetValue () > snrPer.per)
>> + if (event->GetRxPowerW () > RxPowerThresholdW)
>>
>> this bypasses the interference model of YansWifiPhy, and allows you to use
>> a simple threshold, as ns-2 does.
>>
>> As for the value of the CS threshold in the Broch paper, you should sett
>> the EnergyDetectionThreshold attribute in YansWifiPhy to an equivalent
>> value.
>>
>> As for capture... that's not trivial. Maybe just neglect it for the moment
>> and see what results you get.
>>
>> Finally, let me say that if anybody wants to develop a new WifiPhy
>> implementation that uses a simple protocol interference model (i.e., a
>> threshold model like the one in ns-2), I would support merging that.
>> But I think it should be separate from YansWifiPhy.
>>
>> Nicola
>>
>
> Here is what I tried.  From trial and error testing in default ns-3 to find
> the optimal transmit power for various distances between a single sender and
> receiver, I found the receive power (Pr) for the Friis propagation loss
> model to be constant at -78.832 dBm.  I converted this to Watts and made the
> following change to YansWifiPhy:
>
> double RxPowerThresholdW = 0.000000000013085791612451009; //
> 1.3085791612451009e-11
> if (event->GetRxPowerW () > RxPowerThresholdW)
>
> I didn't see any specific CS threshold numbers in the Broch paper, so I
> just went with the ns-3 default of -96.
>
> With this, through trial and error with one sender and receiver 250 m
> apart, I found the optimal transmission power to be 13.9.
>
> Does this sound like a correct approach to simplifying the physical layer
> to be like ns-2 with the receive threshold?
>
> So, I tested the above configuration with the AODV Broch scenario and
> default ns-3 AODV and it seems to have made things even worse.  After a
> couple hundred seconds in the simulation, the performance degrades to 0%
> PDR.  It started with decent performance but quickly approached 0% PDR after
> about 100 simulation seconds.
>
> Thanks,
> Kevin
>
>
>