Receiver problem with wrong characters qpsk adalm pluto

Hello, I have been working on a qpsk transceiver with the adalm pluto for over a month now but without success. I can detect my preamble, but I can't get the message I sent back, does anyone have any idea how to do this?

In the end, I get these characters instead of "IUT "

Answer 1

[Harsh]

Hi Ashvin,

I understand that you want to transmit a text message using ADALM-PLUTO radio. However, you are unable to get the correct output at receiver.

In the following points, I am suggesting two potential causes of the issue and their resolutions.

• Underflow and/or Overflow issue: An underflow flag indicates that there is a loss of samples in transmission. Similarly, an overflow flag indicates that there is a loss of samples during signal reception. Therefore, ensure that there is no underflow or overflow occurring during the communication. The Usage section in following documentation links provide syntax to check or count underflows and overflows respectively.
• https://in.mathworks.com/help/supportpkg/plutoradio/ref/comm.sdrtxpluto-system-object.html#d124e8523
• https://in.mathworks.com/help/supportpkg/plutoradio/ref/comm.sdrrxpluto-system-object.html#d124e7128
• Try changing the carrier frequency of your transmission to an unlicensed band frequency. It is possible that the currently used carrier frequency is receiving interference from other wireless equipment.

Further, you can refer to the following examples as they align with your goal. I think this should be helpful in resolving the issues that you are facing.

• QPSK Transmitter with ADALM-PLUTO Radio in Simulink: https://in.mathworks.com/help/supportpkg/plutoradio/ug/qpsk-transmitter-with-adalm-pluto-radio-1.html
• QPSK Receiver with ADALM-PLUTO Radio in Simulink: https://in.mathworks.com/help/supportpkg/plutoradio/ug/qpsk-receiver-with-adalm-pluto-radio-1.html