USRP B210 BPS modulation and demodulation BER problem

[aster_yeyo]

Can you share any example with sync and guard bits for usrp. I have to fix these things asap. 

I also want to see power delay profile is it possible ?

[aster_yeyo]

even if it is true that it is detecting the trigger through noise so why the index bit is always 0 or 1 ? 

[Case_in_Point]

Your second question had me questioning my initial guess, so I dug into this more and I think I've figured out what's actually going on. The behavior I was seeing related to upping the # of samples causing the triggers to stop was actually tied to the length of the bitstream. As you turn up samples/symbol, you end up with a smaller bitstream per each frame, which eventually means you can't hit the confidence target for the Calculate BER VI. For 0.1 threshold and 0.95 confidence, for instance, you need over 400 bits. So that's what was happening there.

I think the real issue we were running into was that the Rx loop isn't acquiring the same number of samples per frame as our Tx loop is generating. The default Rx code just calculates the frame based off of IQ rate and duration, where the Tx loop makes it based off of other factors. When I matched the # of samples control on my reads to the frame size coming from the Tx loop, I can now get solid BER from the Calculate BER VI. I don't know how much your code is modified from teh example, but give that a try!

[aster_yeyo]

actually i am new to the labview and communication. can you please share your vi files. I want to check how are you deteting the frames. 

Can you also tell me how can I check power delay profile?.

[Case_in_Point]

There's really not any significant change in the code. Open up the PSK Tx example, and look at the Frame Size indicator. Then open up the PSK Rx example, and look at the Number of Samples input for the two Rx Fetch calls. By default they get fed a value calculated based on the IQ rate and duration, but just replace that with a constant that matches what's coming from the Tx example. 

I also don't think we have any examples for power delay profile measurements, especially not with the USRP driver. That seems like a non-trivial application that wouldn't really be able to be implemented in a one-size-fits-all example.