USRP hardware for direction finding using Mathlab

can anyone give me instruction about how to use the Examples of QPSK transmitter and receiver with USRP Hardware . I am unable to understand which code i have to run first and which one to run at last i have two usrp . i want to make one as a QPSK transmitter and second as QPSk receiver .the receiver code have default text messsage which contain hello world! can anyone change it so that it can receive the message transmitted by transmitter . if anyone can give the code of both then it will be very helpful for me.

Answer 1

[Harsh]

Hi Umesh,

I understand that you want to learn about the usage of “QPSK Transmitter/Receiver with USRP™ Hardware” examples. Further, you want to change the code such that it can receive other messages transmitted by the transmitter.

In the following points, I am answering the query in a stepwise manner:

1. Assuming, both USRP boards are connected to the same computer, you need to open two MATLAB windows on that computer.
2. Otherwise, open the MATLAB window on each of the computers to which USRP board is connected.
3. Open the “QPSKTransmitterWithUSRPHardwareExample.mlx” file in one of the MATLAB windows. Ensure that a USRP board with transmit antenna is connected to this computer.
4. Similarly, open the “QPSKReceiverWithUSRPHardwareExample.mlx” file in the other MATLAB window. Ensure that a USRP board with receiving antenna is connected to this computer. You can also use the following command to open the file.
5. Now, execute the transmitter file first, then run the receiver example file.
6. On the successful transmission of the message, the receiver MATLAB window will print the error rate value on the command prompt.
7. To see the received message, you can set the “printReceivedData” variable to “true” at line number 87 of the “QPSKReceiverWithUSRPHardwareExample.mlx” file.
8. Further, you can change the default “Hello World” message to any other message by setting “SimParams.Message” to any other text message at line 28 of the “sdruqpsktransmitter_init.m” file.

Thanks!

[umesh sinha]

I have done all that earlier but in receiver code there this default hello world written. When I run receiver code it shows me that same hello world inspite of showing message send by transmitter

[Harsh]

Okay umesh. I understand that.

For better clarity of the issue, can you please share the file and line number where this default text is written in receiver code?