Re [ns] Wireless LAN throughput

[Saikat Ray]

This is incorrect to do so. You may not send all part of the packets at 11 Mbps, since potential nodes that can only under 1Mbps rate should also be able to understand RTS/CTS.

----------- Original Message ---------

DATE: Thu, 22 Jan 2004 00:53:07
From: Bhavjit Singh Walha <csu00106 at cse.iitd.ernet.in>
To: Chetan Kumar S <chetan.kumar at wipro.com>
Cc: ns-users at ISI.EDU

>
>On Tue, 20 Jan 2004, Chetan Kumar S wrote:
>
>Hi,
>    Actually there are 2 variables in mac-802_11.cc - dataRate_ and 
>basicRate_. A change of basicRate_ 11000000 should do the trick. This 
>would cause all headers and RTS/CTS/ACK to be sent at 11Mbps.
>   I am not sure of other side effects it may have.
>
>Bhavjit
> 
>
>> 
>> 
>> 
>> >Hi,
>> >there are four things that You should take in account:
>> >- In NS ACK are always sent at 1Mbps
>> 
>> Hi,
>> 	I have now disabled RTS/CTS, now I get 5mbps throughput. I am 
>> planning to change the ACK to be sent out at dataRate_, can U please let 
>> me know how I could do this, any pointers/help in this regard would give 
>> me lot of time advantage..
>> 
>> Thanks
>> Chetan S
>> 
>> 
>> >- NS use always the long PLCP preamble format sent at 1Mbps
>> >- by default NS uses RTS/CTS handshake
>> >- Packet's size has also an impact in the % of overhead.
>> >All this factor can  bound the achievable throughput.
>> >Ciao
>> >                           Luigi
>> >
>> > Message: 6
>> > Date: Sat, 17 Jan 2004 22:42:31 +0530 (IST)
>> > From: Chetan Kumar <chetan at protocol.ece.iisc.ernet.in>
>> > Subject: [ns] Wireless LAN throughput
>> > To: ns-users at ISI.EDU
>> > Message-ID: <20040117224157.U15214-100000 at protocol.ece.iisc.ernet.in>
>> > Content-Type: TEXT/PLAIN; charset=US-ASCII
>> >
>> >
>> > Hi All, 
>> > I did couple of experiment on a two node ad-hoc network to
>> > calculate the wirelesslan throughput (the nodes are 5 meters apart).
>> > Here
>> > are the results:
>> >
>> > Mac/802_11 set dataRate_ 11e6
>> > Throughput seen 3.6 MBPS
>> >
>> > Mac/802_11 set dataRate_ 2e6
>> > Throughput seen 1.47 MBPS
>> >
>> > Mac/802_11 set dataRate_ 1e6
>> > Throughput seen 900 Kbps
>> >
>> > So I am getting 90% at 1 mbps, 73% at 2 mbps and 32% at 11 mbps
>> >
>> > Now question is that at 11mbps, the throughput achieved is much less 
>> > then
>> > the theoretical throughput achievable (including the overhead), which is
>> > around 60%. Does someone know what is the reason for this.
>> >
>> > Parameters:
>> > Phy/WirelessPhy set CPThresh_ 10.0
>> > Phy/WirelessPhy set CSThresh_ 5.011872e-12
>> > Phy/WirelessPhy set RXThresh_ 1.15209e-10
>> > Phy/WirelessPhy set Pt_ 0.031622777
>> > Phy/WirelessPhy set freq_ 2457e+6
>> >
>> > Traffic Type:
>> > Application/Traffic/CBR
>> > $cbr_($i) set packetSize_ 1000
>> > $cbr_($i) set rate_ 11m
>> >
>> 
>> 
>
>



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