[Ns-developers] 802.11 10Mhz Channel

[Pei, Guangyu]

Hi,
Here is what I see in DcaTxop:
 
 98 TypeId
 99 DcaTxop::GetTypeId (void)
100 {
101   static TypeId tid = TypeId ("ns3::DcaTxop")
102     .SetParent<Object> ()
103     .AddConstructor<DcaTxop> ()
104     .AddAttribute ("MinCw", "The minimum value of the contention
window.",
105                    UintegerValue (15),
106                    MakeUintegerAccessor (&DcaTxop::SetMinCw,
107                                          &DcaTxop::GetMinCw),
108                    MakeUintegerChecker<uint32_t> ())
109     .AddAttribute ("MaxCw", "The maximum value of the contention
window.",
110                    UintegerValue (1023),
111                    MakeUintegerAccessor (&DcaTxop::SetMaxCw,
112                                          &DcaTxop::GetMaxCw),
113                    MakeUintegerChecker<uint32_t> ())
114     .AddAttribute ("Aifsn", "The AIFSN: the default value conforms
to simple DCA.",
115                    UintegerValue (2),
116                    MakeUintegerAccessor (&DcaTxop::SetAifsn,
117                                          &DcaTxop::GetAifsn),
118                    MakeUintegerChecker<uint32_t> ())
119     ;
120   return tid;
121 }
122 

The default value of 15 was set at line 105. Why do you think that CwWin
has nothing to do with DcaTxop?
 
Gary

 


________________________________

	From: Basim Javed [mailto:basimjaved at gmail.com] 
	Sent: Thursday, July 16, 2009 3:17 PM
	To: Pei, Guangyu
	Cc: Nicola Baldo; ns-developers
	Subject: Re: [Ns-developers] 802.11 10Mhz Channel
	
	
	hi all
	
	CwMin parameter has to do nothing with DcaTxop. In QoS enabled
MAC, each queue handles its own DcaTxop independently. 
	
	regards
	B
	
	
	On Thu, Jul 16, 2009 at 11:23 PM, Pei, Guangyu
<Guangyu.Pei at boeing.com> wrote:
	

		It seems to me that CwMin parameter is controlled by
DcaTxop. Each MAC
		handles its own DcaTxop.  Should we add a virtual
function SetCwMin may
		be added in WifiMac class? For non-QoS MACs, it seems
that each mac has
		only one DcaTxop and it is straightforward to add one.
For QoS  MAC, it
		seems that only beacon Dca needs to be set. Does this
sound ok?
		
		Gary
		


		> -----Original Message-----
		> From: Nicola Baldo [mailto:nbaldo at cttc.es]
		> Sent: Thursday, July 16, 2009 9:03 AM
		> To: ns-developers
		> Subject: Re: [Ns-developers] 802.11 10Mhz Channel
		>
		> Also CwMin should be set to 31 (instead of 15) when
using 802.11b.
		> See IEEE Std. 802.11-2007, section 15.3.3 "DS PHY
characteristics".
		>
		> Nicola
		>
		> Pei, Guangyu wrote:
		> > Hi,
		> >
		> > I double-checked the standard. I believe the
following
		> settings are correct.
		> >
		> > +WifiMac::Configure80211b (void)
		> > +{
		> > +  SetSifs(MicroSeconds(10));
		> > +  SetSlot(MicroSeconds(20));
		> > +  SetEifsNoDifs(MicroSeconds(10+304));
		> > +  SetPifs(MicroSeconds(10+20));
		> > +
		> >
		>
+SetCtsTimeout(MicroSeconds(10+304+20+GetDefaultMaxPropagationDelay().
		> > +GetMicroSeconds ()*2));
		> > +
		> >
		>
+SetAckTimeout(MicroSeconds(10+304+20+GetDefaultMaxPropagationDelay().
		> > +GetMicroSeconds ()*2)); }
		> >
		> > In particular, I believe 304 is the Ack Tx time =
AckSize + PLCP
		> > Preamble + PCLP Header = 8*14 + 144 + 48 = 304
		> >
		> > Thanks,
		> >
		> > Gary
		> >
		> >> -----Original Message-----
		> >> From: Ramon Bauza [mailto:monbauza at gmail.com]
		> >> Sent: Monday, July 13, 2009 3:22 AM
		> >> To: Mathieu Lacage
		> >> Cc: ns-developers at ISI.EDU
		> >> Subject: Re: [Ns-developers] 802.11 10Mhz Channel
		> >>
		> >> Hi,
		> >>
		> >> Thank you for your comments. Please find the new
patch modified
		> >> accordingly to your suggestions. Now,
WifiMacHelpers
		> remain the same
		> >> way as in ns-3-dev.
		> >> I have also added the Configure80211b method to
configure MAC
		> >> parameters.
		> >> However, I would like someone to review the
parameters, since I am
		> >> not very familiar with the 802.11b specification.
As Std
		> 802.11-2007
		> >> states (page 654), I have considered:
		> >>
		> >> - SlotTime = 20us
		> >> - SIFS = 10us
		> >>
		> >> Ramon.
		> >>
		>