Hello everyone,
I'm working on implementation of two-way relaying model using GNU Radio (with GNU Radio Companion as interface) and 3 USRP1s (each has one RFX2400 daughterboard and one VERT2450 antena). The relay node (R) decodes messages from two end nodes (A and B) separately and performs a bitwise XOR on these messages before transmitting the XORed data to end nodes. This model runs well with short message.
However, at the moment, nodes A and node B are running on their own and user can just start/stop transmitting/receiving by hand. It's needed to have timing synchronization. This can be done by adding a beacon in node R. This beacon is a pulse, transmitted each time before node R is able to receive signal. Node A and node B transmit their message once the end of the beacon is received. This process requires system to perform TDM. The flow chart for each node can be found here:
https://www.dropbox.com/s/456s3lucpfa5wnc/AB%20protocol.png
My problem is that I don't know how to design a TDM to manage the transmit/receive phase. In particular, in end nodes, we need to notice the transmitter when the beacon is received and tell it to transmit; in relay node, we need to tell it when to transmit the beacon, when to receive (not simultaneously).
Does anyone have experience with TDM on USRP and GNU Radio? Please give me some clue for that. Should I write some new blocks or modify the python script generated by GNU Radio Companion?
Any help would be greatly appreciated.
Hoang from Vietnam.
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Ngo Khac Hoang
Faculty of Electronics and Telecommunications -
University of Engineering and Technology (UET) - Vietnam National University, Hanoi (VNU)
Vice-president of Student Association of UET
Mobilephone: +84.163.682.7874
