[Discuss-gnuradio] How to implement a TDMA system

[Pan, Luyuan]

Hi everyone,
I want to implement a TDD system with three USRP2 and an IBM server with 
three Ethernet cards. The scenario is one relay and two nodes exchange 
data through the relay, I want them to transmit data in their fixed time 
slot, it does not need to be too precise, about 100 milliseconds per 
slot is OK. The question is:
1. Can I achieve my goal with the current equipment?
2. I want to use the time-stamp in UHD to precise control the time to 
send and recv, but without external clock, does the UHD have to use the 
external clock to get the time?
Thank you in advance!
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Best regards,
Pan, Luyuan