How to add a WiFi basic rate (AddBasicMode)

[Rober]

Hi all,

I'm trying desperately (and after days searching these posts) to get a
way to add new basic rates to the IEEE 802.11 Standard Basic Set of
rates.

I have set 802.11b mode by using:

WifiHelper wifi = WifiHelper::Default ();
wifi.SetStandard (WIFI_PHY_STANDARD_80211b);

and try to add the 2 Mbps rate to the basic set with:

Config::SetDefault ("ns3::WifiRemoteStationManager::AddBasicMode",
StringValue ("DsssRate2Mbps"));

That's the only way I could imagine to add a new basic rate. It
compiles OK, but it fails when executed saying:

msg="Could not find attribute
ns3::WifiRemoteStationManager::AddBasicMode", file=../src/core/model/
attribute-list.cc, line=69

Please, can anyone help me?

Thanks a lot!

Rober

[Ruben Merz]

Hi Rober,

I am bit confused by what you want to do. If you configure the physical
layer to use WIFI_PHY_STANDARD_80211b, you then have access to the DSSS
1 Mbps and 2 Mbps.

Ruben

[Rober]

Hi Ruben,

The problem is that ns-3 takes as basic rate only 1 Mbps (I can check
it in PHY layer in the pcap files). But in real life, some cards use
higher rates (including 11 Mbps) as basic rates. So you can see ACKs
at 2, 5.5 or 11 Mbps in real tests.

So, I need to set these higher rates for ACKs in my simulations, but
ns-3 only uses 1 Mbps (the only basic rate for 802.11b in ns-3) for
ACKs. I can't use "AddBasicMode" to add more basic rates because it
fails.

Bye.

[Ruben Merz]

On 6/5/11 3:06 PM, Rober wrote:
> Hi Ruben,
>
> The problem is that ns-3 takes as basic rate only 1 Mbps (I can check
> it in PHY layer in the pcap files). But in real life, some cards use
> higher rates (including 11 Mbps) as basic rates. So you can see ACKs
> at 2, 5.5 or 11 Mbps in real tests.

Sure, no issue with that.

> So, I need to set these higher rates for ACKs in my simulations, but
> ns-3 only uses 1 Mbps (the only basic rate for 802.11b in ns-3) for
> ACKs. I can't use "AddBasicMode" to add more basic rates because it
> fails.

I should have read better the error message. You can't use AddBasicMode
this way. As the error message says, it is not an attribute. Now, this
function is used only with an STA mac. With an ad hoc wifi mac or
others, the wifiMode of control frames or management frames corresponds
to the m_defaultTxMode in WifiRemoteStationManager (through the
m_bssBasicRateSet, see WifiRemoteStationManager::GetControlAnswerMode).

I believe that what you'd like is a way to change the rate for
management frame and control frames. I am right now not sure what is the
best way to do it. Can you please submit a bug entry on
https://www.nsnam.org/bugzilla/ (select the wifi module) and we'll keep
on from there. I'm happy if you have any suggestion and/or patch.

Best
Ruben

[Rober]

Said and done. I've created a new bug entry on bugzilla, here's the
url:

Bug 1181
https://www.nsnam.org/bugzilla/show_bug.cgi?id=1181

Thank you for your help.

Rober

On Jun 5, 3:47 pm, Ruben Merz <ru...@net.t-labs.tu-berlin.de> wrote:
> On 6/5/11 3:06 PM, Rober wrote:
>
> > Hi Ruben,
>
> > The problem is that ns-3 takes as basic rate only 1 Mbps (I can check
> > it in PHY layer in the pcap files). But in real life, some cards use
> > higher rates (including 11 Mbps) as basic rates. So you can see ACKs
> > at 2, 5.5 or 11 Mbps in real tests.
>
> Sure, no issue with that.
>
> > So, I need to set these higher rates for ACKs in my simulations, but
> > ns-3 only uses 1 Mbps (the only basic rate for 802.11b in ns-3) for
> > ACKs. I can't use "AddBasicMode" to add more basic rates because it
> > fails.
>
> I should have read better the error message. You can't use AddBasicMode
> this way. As the error message says, it is not an attribute. Now, this
> function is used only with an STA mac. With an ad hoc wifi mac or
> others, the wifiMode of control frames or management frames corresponds
> to the  m_defaultTxMode in WifiRemoteStationManager (through the
> m_bssBasicRateSet, see WifiRemoteStationManager::GetControlAnswerMode).
>
> I believe that what you'd like is a way to change the rate for
> management frame and control frames. I am right now not sure what is the

> best way to do it. Can you please submit a bug entry onhttps://www.nsnam.org/bugzilla/(select the wifi module) and we'll keep