Hi all, I am trying to use the ofdm_tx.grc and ofdm_rx.grc to transmit data from one N210 controlled by a host to another N210 controlled by a separate host. Eventually I want to build an 8x8 MIMO system using OFDMA. I want to verify that the correct data is being received so I sent all of the decoded payload data into a file sink. The file I sent has 10e6 random samples from 0-255 being stored into bytes. I received at least 5x that amount to ensure that I got all the data. I imported the received data and the known sent data into Matlab and performed the cross-correlation. The figure looks kind of okay as it showed multiple peaks (see figure below). However when I went to actually calculate the BER, I never got more than 20% of the correct bits. It was behaving strangely as 20% of the bits would be correct in a row, and then after that it would just be completely wrong. I know the ofdm_tx.grc graphs inserts metadata into the signal, and my theory is that the meta data is also being decoded and it won’t match exactly what was sent in the file because of the extra information. My understanding might be completely off, so if anyone can clarify it would be greatly appreciated! I just want to be able to have a way that calculates the BER between what is transmitted and what is received.
Thank you for your time!! [cid:image002.jpg@01D3B539.503832E0] Sarah Tran Electrical Engineer
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