Communication chain on USRPs using QPSK » History » Version 9
Version 8 (PASCHOS, Alexandros, 12/15/2015 12:30 AM) → Version 9/39 (PASCHOS, Alexandros, 12/15/2015 12:32 AM)
h1. Communication chain on USRPs using QPSK
h2. Setup
To successfully connect two USRPs using the inventory mentioned earlier, it is required to have an Ethernet cable connected from the PC to one of the USRPs (in this case the Tx USRP) and then a MIMO cable that connect the Tx USRP to the Rx USRP. This way, the Rx USRP is also connected to the PC. The RF cable is connected from the USRP, using a 30dB attenuator to the Rx USRP. Below is a diagram of the setup. An update to the version of the FPGA image file might needed for LabVIEW Communications. In the NI USRP Utility an update to the images is done as demanded by the software.
p=. !{width: 40%}https://sourceforge.isae.fr/attachments/download/1491/setupDiagramUSRPs.png(Setup Diagram USRPs)!
_Figure 2.1 Set-up diagram of the USRPs_
h2. Transmission with QPSK
The block diagram of the communication chain is shown below in figure 4. An existing example of USRP communication with PSK was used for guidance.
p=. !{width: 40%}https://sourceforge.isae.fr/attachments/download/1492/communicationChainUSRPs.jpg(Communication Chain USRPs)!
Bits are generated (Galois) using a PN (pseudo noise) sequence. The signal is then modulated, filtered and sent to the transmitting USRPS, which is continuously transmitting. The receiving USRP will obtain the data from the transmitting USRP, and the signal is filtered with a matched filter, demodulated, and the constellation is plotted.
p=. !{width: 40%}https://sourceforge.isae.fr/attachments/download/1492/communicationChainUSRPs.jpg(Communication Chain USRPs)!
On the front panel of the transmission there are several inputs and outputs:
h2. Setup
To successfully connect two USRPs using the inventory mentioned earlier, it is required to have an Ethernet cable connected from the PC to one of the USRPs (in this case the Tx USRP) and then a MIMO cable that connect the Tx USRP to the Rx USRP. This way, the Rx USRP is also connected to the PC. The RF cable is connected from the USRP, using a 30dB attenuator to the Rx USRP. Below is a diagram of the setup. An update to the version of the FPGA image file might needed for LabVIEW Communications. In the NI USRP Utility an update to the images is done as demanded by the software.
p=. !{width: 40%}https://sourceforge.isae.fr/attachments/download/1491/setupDiagramUSRPs.png(Setup Diagram USRPs)!
_Figure 2.1 Set-up diagram of the USRPs_
h2. Transmission with QPSK
The block diagram of the communication chain is shown below in figure 4. An existing example of USRP communication with PSK was used for guidance.
p=. !{width: 40%}https://sourceforge.isae.fr/attachments/download/1492/communicationChainUSRPs.jpg(Communication Chain USRPs)!
Bits are generated (Galois) using a PN (pseudo noise) sequence. The signal is then modulated, filtered and sent to the transmitting USRPS, which is continuously transmitting. The receiving USRP will obtain the data from the transmitting USRP, and the signal is filtered with a matched filter, demodulated, and the constellation is plotted.
p=. !{width: 40%}https://sourceforge.isae.fr/attachments/download/1492/communicationChainUSRPs.jpg(Communication Chain USRPs)!
On the front panel of the transmission there are several inputs and outputs: