I used costas loop for each synchronization and it worked
My thinking was wrong I thought the signals from different usrps are synchronized together without controlling the offset of usrps
I use usrp N210
Now i need to know frequency offset of each usrp
And my professor and our team read a thesis about beamforing
In the page there were 3 types of similar one
First one, send continuous signal and send continuous signal as a feedback
Second one, send continuous signal and send 1bit feedback
Last one, send bits and send bits as a feedback
Anyway thanks for your helping
As you mentioned I will try to do it manually and I will check the outcome
I think i need more help in the future
Thanks for now