[USRP-users] Overflow with B210 for 2by2 MIMO design

Gilad Beeri (ApolloShield) gilad at apolloshield.com
Mon Mar 11 04:44:33 EDT 2019


I had a MacBook Pro 2013 which also couldn't withstand more than ~ 8-9 MS/s
w/o overflows on its USB 3.0 port.
Not all USB controllers show the same performance level, not all of them
actually get to the specified 5 Gb/s rate.
I suggested you take everything as-is and test it on a computer with an
Intel USB controller (also: see the benchmark and USB-version tests
Xavier was referring to).


On Sun, Mar 10, 2019 at 7:59 PM Ayaz Mahmud via USRP-users <
usrp-users at lists.ettus.com> wrote:

> Trying to develop 802.11n (a 2 by 2 MIMO) standard by using two B210s.
> Initially started with the existing flow of
> GnuRadio/examples/digital/OFDM/tx.ofdm.grc. Lets take only the transmitter
> side for this question.
>
>
>
> Things that are changed in OFDM.grc:
>
>    1. The OFDM allocator block: The sync word. It is changed as per the
>    rule of 802.11n. That is, we use preambles (STF/LTF…)
>    2. Made two exact same chains (just copying one flow), which
>    previously was one, and fed into USRP-2 input ports.
>    3. Sampling rate : 20 MSPS
>
>
>
> Problem :
>
>    1. Overflow occurs. (I am using USB 3.0 interface, on MAC). Two of the
>    interfaces connected with this same laptop. Max sample rate it can handle
>    is about 4MSPS.
>
>
>
> I have tried saving the files in the RAM and then transmit. Does not
> improve the situation much.
>
>
>
> Need suggestions on where should I look for the fix.
>
>
>
> Thanks.
> _______________________________________________
> USRP-users mailing list
> USRP-users at lists.ettus.com
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>
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