Hi Everyone!
My name is Melesio Eduardo and I'm a student in the Autonomous University of San Luis Potosí in México. Recently I've been working with Labview and specifically with the NI USRP-2920 platform. I've been having some problems trying to establish a correct communication between two USRPs (Tx and Rx) and I was wondering if I can get some help in this community. Here are my problems; I'll try to be as briefly as possible:
- For the purposes of my course I’ve been working with the following Lab Manual: DIGITAL COMMUNICATIONS PHYSICAL LAYER EXPLORATION LAB USING THE NI USRP™ PLATFORM by Robert W. Heath Jr., Ph.D., P.E. (I’m pretty sure you know which one I’m talking about).
- Along with the manual I was provided with the corresponding ‘Instructor Resource CD’ in which we can find the correct VIs for every ‘lab’ in the manual (From 0 to 8).
- In ‘lab 2 part 1’ the Author proposed establish a communication link over a real wireless medium, and so I followed every instruction the Author gives but I just can’t successfully recover the symbols the Tx is transmitting.
I let you know that I’ve been trying to make this work for the last 2 months, so I tried pretty much everything I know (so far) but nothing seems to be working. I’m using the top_tx and top_rx VIs which are suppose to be the correct ones according to the manual. top_tx its working just fine I guess, at least I’m not getting any errors there. But when it comes to top_rx after trying a lot of things I was able to successfully display the Received Signal and the Eye Diagram, but I can’t make the Signal Constellation and Power Delay Profile to show. When I run the VI I get the following error:
-20003 (direct_equalizer.vi)
Possible reason(s):
- The number of samples must be > 0.
I don’t know why I’m getting an error when the VIs are suppose to be the correct ones, the ones that the Author provides you, but I tried to modify it so I don’t need a equalizer and the program runs without any errors but it just doesn’t show the constellation, even worse, I checked the sub_VIs that top_rx is using and apparently is not recovering any symbols, just the complex waveform. I had done and checked so many in top_rx that I just have a ton of questions, but before start asking them I would like to know if anyone in this community had problems similar with these labs or if anyone can provide me with a working set of VIs for this manual.
I know it seems that I not trying enough but trust me, I had. I’m sure that if you guys ask me if I had done something in particular I will have and proper answer. By the way, I tried to run all the VIs provided by the Author but no one works as it is supposed to, even the last one with OFDM which doesn’t need a equalizer and top_rx runs without giving any errors but is the same, I can’t recover symbols.
Hope you can help me,
thank you for reading.
