Spatial Streams

[bouthayna zouaghia]

    Hello,

         phy.Set ("TxAntennas", UintegerValue (8));

          phy.Set ("RxAntennas", UintegerValue (8));

This source code fix the number of spatial streams to 8 or fix the number of antennas to 8 ?

[Tom Henderson]

You need to configure both the "MaxSupportedTxSpatialStreams" and
"MaxSupportedRxSpatialStreams" attributes of WifiPhy to 8, and the
"TxAntennas" and "RxAntennas" to 8 (otherwise, you will not have enough
antennas), and you should configure the nodes for the 802.11ac standard.
Then it might work (although I am not sure whether there is any
example or test of this high number of spatial streams in the existing
codebase).

[Bouthayna Zouaghia]

for the NS3.26 the attributes MaxSupportedRxSpatialStreams and MaxSupportedTxSpatialStreams are not defined, just we have TxAntennas and RxAntennas and we can fix them to 8.

But, for the NS3.27, MaxSupportedRxSpatialStreams and MaxSupportedTxSpatialStreams are defined   and they can have  max 4 SS because max 4 antennas are allowed

     TxAntennas and RxAntennas are not defined.   

       phy.Set ("Antennas", UintegerValue (4));

        phy.Set ("MaxSupportedTxSpatialStreams", UintegerValue (4));

          phy.Set ("MaxSupportedRxSpatialStreams", UintegerValue (4));

  My question is when i use 3.26        

          phy.Set ("TxAntennas", UintegerValue (8));

           phy.Set ("RxAntennas", UintegerValue (8));  means that i fix the number of SS to 8   ???

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[Tom Henderson]

On 01/22/2018 06:51 AM, Bouthayna Zouaghia wrote:
> for the NS3.26 the attributes MaxSupportedRxSpatialStreams and
> MaxSupportedTxSpatialStreams are not defined, just we have TxAntennas
> and RxAntennas and we can fix them to 8.
> But, for the NS3.27, MaxSupportedRxSpatialStreams and
> MaxSupportedTxSpatialStreams are defined   and they can have  max 4 SS
> because max 4 antennas are allowed
> TxAntennas and RxAntennas are not defined.
>        phy.Set ("Antennas", UintegerValue (4));
>         phy.Set ("MaxSupportedTxSpatialStreams", UintegerValue (4));
>           phy.Set ("MaxSupportedRxSpatialStreams", UintegerValue (4));
>   My question is when i use 3.26
>
>
>           phy.Set ("TxAntennas", UintegerValue (8));
>
>
>            phy.Set ("RxAntennas", UintegerValue (8));  means that i
> fix the number of SS to 8   ???

My guess is that you will not be able to directly configure ns-3.26 to
do this (that release does not support it).

For ns-3.27, you are correct; the 'Antennas' attribute replaces the
separate 'TxAntennas' and 'RxAntennas' attributes. However, they should
not be limited to the value 4. I see a limit of 8 enforced in the
code, not 4.

[Bouthayna Zouaghia]

Yes I try to execute the code in ns3.27

       phy.Set ("Antennas", UintegerValue (8));

         phy.Set ("MaxSupportedTxSpatialStreams", UintegerValue (8));

           phy.Set ("MaxSupportedRxSpatialStreams", UintegerValue (8));

 

But it shows me messages errors that the number of antennas should be fixed between 1 and 4  (1=<number of antennas<=4 ), and the number of spatial streams must be <= the number of antennas , so the number max of spatial streams is 4 .===========================> ns3.27 not allows me to fix the number of spatial streams to 8 ,  max number is  4. You understand me please?? I need to be sure in the order to evaluate the performance of Minstrel HT in VHT network.    

[Tom Henderson]

On 01/22/2018 07:32 AM, Bouthayna Zouaghia wrote:

Yes I try to execute the code in ns3.27

       phy.Set ("Antennas", UintegerValue (8));

         phy.Set ("MaxSupportedTxSpatialStreams", UintegerValue (8));

           phy.Set ("MaxSupportedRxSpatialStreams", UintegerValue (8));

 

But it shows me messages errors that the number of antennas should be fixed between 1 and 4  (1=<number of antennas<=4 ), and the number of spatial streams must be <= the number of antennas , so the number max of spatial streams is 4 .===========================> ns3.27 not allows me to fix the number of spatial streams to 8 ,  max number is  4. You understand me please?? I need to be sure in the order to evaluate the performance of Minstrel HT in VHT network.    

You are correct; I just tried it myself and got the following:

assert failed. cond="antennas > 0 && antennas <= 4", msg="unsupported number of antennas", file=../src/wifi/model/wifi-phy.cc, line=1312

So I would conclude that 8 spatial streams are not supported in ns-3.27.

- Tom

[Bouthayna Zouaghia]

Thank you very much for your response , you confirmed the result of simulation.

Thank you for your time .

[Sebastien Deronne]

802.11n/ac MIMO only supports up to 4 antennas in the standard, so we restricted this in the code.

8 antennas might be supported once 802.11ac MU-MIMO is implemented.

Also note that TxAntennas and RxAntennas are deprecated and will soon be removed.

[Bouthayna Zouaghia]

Thank for the response Sebastien. So How can I use 8 spatial streams, I need to understand it very much to do the evaluation of rate adaptation algorithm in VHT  network. 

--

[satoshi nokomorko]

HI sebastein,

Is MU MIMO available with 80211n?

When can we expect the MU-MIMO to be implemented?

[Rediet]

No MU-MIMO is currently implemented in Wi-Fi.

[柯瀞雯]

Hello!

I have similar question.

Is MIMO available with LTE?

Thanks!