Transmission-Reception using USRPs(B210s) with 5G NR Waveform Synchronization failing

Hi Everyone,

I am trying to create a 5G environment with USRPs, one as transmitter (PC1 with MATLAB) and other as receiver (PC2 with MATLAB) and they are connect with wired antennas.

I am generating the 5G NR waveform at transmitter side and sending it to receiver over connected antennas.

The waveform signal is sent for 10 seconds and receiver also receiving it for same duration with 1 second provided for transmission delay (through USRP's USBs and wires). However, the synchronization is failing and the waveform I received are not the same which leads to inability to extract the sent waveform properties like PDCCH and PDSCH, data, etc. The datatypes of sent and received waveform are also different (Complex-double at transmitter, Complex-int16 at receiver).

I used the below link for designing the waveform for transmission.

https://in.mathworks.com/help/5g/ug/5g-nr-waveform-capture-and-analysis-using-software-defined-radio.html

Although there is no details about the receiver side in the above link.

If someone faced the similar issues, kindly suggest some help

If there exist any tutorial for this kind of work Please share?

Thanks

Answer 1

[Yash]

Hi Tafseer,

I understand that you are experiencing synchronization issues between your transmitter and receiver in your 5G environment. One potential issue could be the difference in data types between the sent and received waveforms. You may need to convert the data types to ensure they match. Additionally, you may need to adjust the transmission delay to properly synchronize the two devices.

Here is the code reference you can use for converting the data types, you may choose anyone of them to convert to another:

% Convert complex-double to complex-int16
tx_waveform_int16 = int16(tx_waveform * 2^15);

% Convert complex-int16 to complex-double
rx_waveform_double = double(rx_waveform) / 2^15;

As for the synchronization issue, you may need to adjust the transmission delay to properly align the waveforms. You can try adjusting the delay in increments of 100 microseconds until you achieve synchronization.

Hope this helps!

[Tafseer]

Thanks for your answer Yash.

Answer 2

[wireless]

Dear Tafseer,

I am also interested in transmitting and receiving the 5G signal to prepare a lab practice.

Have you managed to solve the problem? Could you tell me how you did it?

Thank you very much.

[Tafseer]

Hi,

The problem can only be managed, using the suggestion given by "Yash" if you can see the answer from him.

The change is datatype in both side (or one) is obvious, so please do that, the tricky part is transmission delay which you need to adjust according to your setup environment as delay can be different for different cases.

Hope this help.

Regards,

[wireless]

thank Tafseer, and how did you solve the delay between Tx and Rx in your case?

Thank you.

[Tafseer]

Hi

By adjusting the delay in increments of 100 microseconds from transmitter side untill I achieved synchronization (on Receiver Side).

[wireless]

Thanks for your answer!