On 02/11/2013 02:51 PM, Lara Deek wrote: > Hello, > > I have a question about the details of transmitting using gnuradio. I > have set up a 2x2 MIMO transmitter using 2 USRP2's (or N200's) that > are connected via a MIMO cable. In C++, I initialize a single USRP > sink, and set the # channels to 2 (excluding the other settings). > > I am currently using the uhd send() function to transmit data, and my > first question is: Does issuing a single send() function transmit > samples on both USRP2's simultaneously, to achieve MIMO spatial > diversity? > > I also want to send different samples on each USRP2, to achieve MIMO > spatial multiplexing. Since the buffer that is passed to the send() > function is a vector, does specifying a vector of size 2, with each > vector holding different data, do the trick? In that case, to achieve > MIMO diversity, the 2 vectors would have to carry the same data, > correct? >
Well in gnuradio, you dont have access to the send function. The scheduler will deliver two streams of equal length (from 2 ports). Inside of gr-uhd, internally the send() routine takes as an argument a vector of points, in this case of size 2. If you are curious about the UHD API usage, there is an example/rx_multi_samples.cpp in uhd. Its RX, but the usage of the streamer and 2 channels is very similar. -josh > Thanks, > Lara > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
