[Discuss-gnuradio] Fwd: Transmitt OFDM signal by X310

Hi,

This is the first time I post and hope every can understand I'm not good at described by English. If I against the rules in here please let know, I will modify ASAP.

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I have used "tx_ofdm.grc" and "rx_ofdm.grc" which in /gr-digital/examples/ofdm on Gnuradio 3.7.10.1. to generate an OFDM signal and transmitt it by two X310.(I didn't change any parameter in ofdm tx/rx)

Why my sample rate set to 50M, and Rx can't completly received data from Tx?

My USRP Source and USRP Sink's parameter as below:

Center Frequency: 5G
Sample Rate: 1M /10M / 25M / 50M
TX / RX Gain:31.5
Gain Type: absolute(dB)
RF board: UBX
Ethernet port: 10G
Transmitt Distance: 1.5 meter (Line of sight)

I have do simulation by using "OFDM transmitter" block and OFDM Receiver block. And BER can reach approximately 10e-5 and PRR (Packer receive rate) can reach 1.

Implementation by X310 with sample rate:1M, 10M 25M still can reach almost 10e-5(BER), and PRR can actully reach 1. But when I increase sample rate to 50M or more, BER just can reach approx. 10e-2 and PRR just can reach approx. 0.98.

I think the BER just can reach 10e-2 is not reasonable with dist just 1.5m and gain set to maximum, so I connect two X310's tx and rx port with SMA cable to do wired transmission and BER still at 10e-2, PRR still at 0.98.

Here is the detail of my transmission:

First,

Generate a 240,000 Bytes data combined with 0~255 integer by using "Random Source" block and put it into "tx_ofdm.grc" to generate OFDM signal and saved by "File Sink".

Second,

Put OFDM signal generated in "First" into "X310 Tx", and transmitt to X310 Rx then put the data which received from "X310 Rx" to do demodulation by "rx_ofdm.grc" and calculate BER and PRR.

By the way, It seems have the same problem when I used E312 as Tx and X310 as Rx in same USRP parameter and sample set to 1M, BER just can reach 10e-2, PRR just can reach 0.97~0.98 whatever with wired transmission or wireless transmission(dist. 1.5m).

From:	魏志嘉
Subject:	[Discuss-gnuradio] Fwd: Transmitt OFDM signal by X310
Date:	Mon, 20 Nov 2017 09:50:25 +0800