2 x MIMO Transmitter using USRPN210

Hi

I am trying to use two USRPN210 to transmit using 2 transmit antennas
for
MIMO,. I have successfully constructed a receiver using 2 USRPs with
Reciever MIMO with 2 reciever antennas having a daughter board XCVR2450
using the freely available file multi_sampler.cpp … I have been able to
recieve the signals synchronously with zero phase offset on both USRPS
which are interconnected through the MIMO cable successfully.
Now At the transmitter end I have 2 USRPs interconnected through
MIMO
cable having the daughter board XCVR2450 and the USRP connectedd to the
host PC … I have been trying to modify the tx_sample_to_file to enable
MIMO transmitter but I haven’t solution as yet
for 2x MIMO reciever i have reffered mimo_sync_with_usrp.pdf document,
but
is there any similar procedure to achieve 2X MIMO for transmitter

Thanks

Regards

RAM

On 05/22/2013 02:11 AM, Ramcharan M C wrote:

cable having the daughter board XCVR2450 and the USRP connectedd to the
host PC … I have been trying to modify the tx_sample_to_file to enable
MIMO transmitter but I haven’t solution as yet
for 2x MIMO reciever i have reffered mimo_sync_with_usrp.pdf document, but
is there any similar procedure to achieve 2X MIMO for transmitter

The synchronization procedures are basically agnostic to RX or TX. So
the code for setting up PPS source, REF source, and syncing USRP time is
going to be the same regardless.

The only real difference between RX and TX, is that on RX, you ask for
samples from each stream at a particular time, this aligns the stream.
But on TX, the alignment of transmitted data is caused by the time stamp
in the transmit metadata.

Check out some of the examples using tags to control transmit time:
http://code.ettus.com/redmine/ettus/projects/uhd/wiki/GNU_Radio_UHD#Using-UHD-Software-with-GNU-Radio

Also, you can use gnuradio-companion to do this really easily. You can
make a 2 channel sink block, set the time and ref sources with drop down
menues, click run, and the data alignment is automatically handled.

-josh