Hi Rahman,
Just like you, my USRPs have suddenly started failing the CRC for every
packet.
By changing the frequency to 1MHZ I'm back to 99% correctly received :) From
searching the mailing list it looks like it's related to the increased
frequency offset due to aliasing at the higher frequencies
Thanks Mike for the comment. I did change the bandwidth, but some error
poped up at runtime for 1.5. Lower values like 0.1 or 0.2 did not change the
behavior of the receiver. Still no correct packet. I receive the packets
though but they fail the CRC check I guess, since I get this "ok:false"
statu
missed off the filename: ofdm_receiver.py
:)
On 17 June 2010 10:27, Mike Jameson wrote:
> Hi Rahman,
>
> Try broadening the bandwidth of the receiver to allow for the frequency
> offset between your USRP2s:
>
> In /usr/lib/python2.6/dist-packages/gnuradio/blks2impl
>
> on line 67 look for "tb
Hi Rahman,
Try broadening the bandwidth of the receiver to allow for the frequency
offset between your USRP2s:
In /usr/lib/python2.6/dist-packages/gnuradio/blks2impl
on line 67 look for "tb = bw*0.08"
change this to a higher value such as "tb = bw*1.5"
This works for me using usrps.
Mike
On
Guys,
I'm working on the same thing, I'm trying to receive something with OFDM
example, USRP2 and XCVR boards. But it doesn't work. The transmitter is
sending and the rx signal is crystal clear with spectrum analyzer but no
packet is caught.
Could anyone of you send me the command you're using at
Hi Chris,
The default settings do drop alot of packets as you are seeing.
These are some of the things I've adjusted which happen to have brought
my packet reception rate up to 99% using 1 USRP with a Basic RX and
TX joined with a 10db attenuator:
- For benchmark_tx.py and benchmark_rx.py add '-
Thank you Fisheep, you confirmed what I was thinking but, I don't Know why,
the packets are been received with no errors, I lost packets but the packets
that I receive are good.
I don't Know how GNU Radio implementation maps 1024 bytes over 200 carriers
with a bpsk modulation, and then the transm
Hi,
I'm not sure why you can't receive all the packet correctly, but I can
briefly tell you how ofdm implement in GNU Radio.
First, fft_length=512 means it will take 512 subcarriers to do ifft/fft, and
occupied_tones=200 means it only take 200 subcarriers to put your modulation
symbol. Besides,
Hello everybody,
I' am trying to test and understand the OFDM Modulation implemented in GNU
Radio. I'm using the deafult values, fft_lenth=512, occupied_tones =200,
cp_length= 128 and bpsk modulation, besides, I'm using a RFX900
Daughterboards on USPR and I'm connecting the TX and RX with a coax