From mboxrd@z Thu Jan 1 00:00:00 1970 From: Date: Sun, 19 Dec 2010 23:59:03 -0000 Subject: No subject Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ath9k-devel@lists.ath9k.org
* If your RX chainmask has >1 radio enabled, you'll always be doing<= br> receive-side "diversity" (which is really "combining" (= MRC) if I
understand the technology correctly on multi-radio atheros 11n cards);
* If your TX chainmask has >1 radio enabled and the TX descriptor has the relevant chainmask bits set, you should be transmitting on both
antennas regardless of the rate. I honestly haven't verified it (I'= ve
only verified that behaviour for transmitting legacy rates out of the
11n chips);

* For rates < MCS8 (and legacy rates) there's further TX-side tricke= ry
that can be going on which I'm not too up-to-date on. For example,
some (all?) of the 11n chips allow you to optionally transmit MCS0-7
using STBC. But iirc, STBC is only enabled for 1-stream TX.

In short, if you've got all the radios enabled =C2=A0for RX and ath9k i= s
enabling both/all radio chains when TX'ing, I think the answer is
"yes" for you. :)

Adrian

On 16 February 2011 22:47, Baldomero Coll <baldo.ath9k at gmail.com> wrote:
> I'm not sure, but I've read somewhere that by default the two = antennas are
> used.
> It is true that I'm not interested in selecting the number of ante= nnas, what
> I really want is that the MIMO capability is exploited if I'm usin= g 802.11n
> HT IBSS operation mode.
> Can someone confirm that by default the two antennas (spatial diversit= y) are
> being used when we create the HT IBSS network?
>
> 2011/2/16 Mohammed Shafi <= shafi.ath9k at gmail.com>
>>
>> On Tue, Feb 15, 2011 at 2:35 PM, Baldomero Coll <baldo.ath9k at gmail.com>
>> wrote:
>> > Hello,
>> >
>> > Can you please tell me how do you select one o two antennas?<= br> >>
>> I don't know why you should do that. I guess changing the tx/r= x
>> chainmask will do after it was read from eeprom.
>>
>> >
>> > I'm using a similar setting than you:
>> > Linux kernel: 2.6.32-28-generic-pae.
>> > Driver: compat-wireless-2011-01-17 and iw-0.9.21 with the pat= ch
>> > suggested by
>> > Alex.
>> > Radio card: Ubiquiti SR71x
>> >
>> > Thanks in advance,
>> > Baldomero
>> >>
>> >> Hi all,
>> >>
>> >> I would like to confirm my findings. My test platform con= figurations
>> >> are
>> >> follow.
>> >> Board: pcengine alix3d2
>> >> Linux kernel: 2.6.35 from linux-wireless git
>> >> Driver: compat-wireless-2011-01-17 and iw-0.9.21 with the= patch
>> >> suggested by Alex.
>> >> Radio card: Ubiqiti SR71a on channel 36 with HT40+
>> >> Measurement tool and settings: Iperf, UDP, 100Mb offered = load
>> >>
>> >> Recored throughput: 50-54Mbps (one antenna); 78-80Mbps (t= wo or three
>> >> antennas).
>> >
>> >
>> > _______________________________________________
>> > ath9k-devel mailing list
>> > ath9k-devel at li= sts.ath9k.org
>> > https://lists.ath9k.org/mailman/listinfo/ath9k-devel<= /a>
>> >
>> >
>
>
> _______________________________________________
> ath9k-devel mailing list
> ath9k-devel at lists.ath9k= .org
> https://lists.ath9k.org/mailman/listinfo/ath9k-devel
>
>

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