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youlizhao / ofdm

OFDM programs for USRP UHD version
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OFDM Receiver Problem #4

Open youlizhao opened 12 years ago

youlizhao commented 12 years ago

(1) Why can we find two preambles using benchmark_tx.py + benchmark_rx.py? (2) How to understand sig[0]? (3) Sleeping in Tx leads to lower PRR in Rx, Why?

youlizhao commented 12 years ago

(1) The first preamble is the real packet position, while the second is the end of a packet. It is caused by low background noise. Current, I just use a threshold to handle this stuff. It seems that the TIMEOUT outputs are more often. :-(

Also, I observed that some pkt error is caused by mis-interpreation of header, e.g., length. Some loss packets are due to lack of preambles.

(2) Each time, this block only consumes one input item. So it is easy to understand sig[0] = 0 or sig[0] = 1.