How to enable synchronous transmission from two antennas? Thanks!

Hi All,

I understand that I am asking a question that has been asked several
times — how to enable synchronous transmission from two antennas?
Basically, I want see if I could send two streams through two antennas
simultaneously while the symbols of the two streams are synchronized.

I found this recent thread
http://www.mail-archive.com/[email protected]/msg12571.html
about the same problem, and I was just wondering how things have
developed, like the m-block code and in-band code. If they are ready,
where could I get them? Thanks a lot in advance for any hint.

I also checked this link
http://www.gnuradio.org/trac/wiki/MultiUsrp
and found that it seems to be about allowing synchronous reception,
and I am not sure whether the same hardware connection works for
synchronous transmission. Again, thanks in advance for any hint.

In fact I equipped one USRP board with two daughter boards (RFX2400,
rev30), and I initially hoped that one USRP board could drive two
transmitting antennas synchronously. Is this possible? Thanks.

Zenny