/Best Regards,
Isen I-Chun Chao/
On Sat, Nov 29, 2014 at 6:21 AM, Bastian Bloessl <address@hidden
<mailto:address@hidden>> wrote:
Hi Isen,
On 2014-11-29 07:01, Isen I-Chun Chao wrote:
Hi,
I am using gr-ieee-802-11 and putting a custom block, which is
responsible for adding a 90-sample preamble at the head of incoming
sample stream, right after the output of WiFi PHY Hier, as attached
figure, generator.png. So the sample stream is changed as attached
figure, adding_preamble.png.
However, in the case of use of transceiver.grc, I can still
successfully
decode received data, which is keep printing out "Hello World!".
Does anyone know why adding extra samples at the head of
transmission
samples does not affect the receiving results? Does it because
somewhere
in Rx side detect the OFDM preamble so the payload can be normally
processed without being affecting by the extra samples placed before
OFDM preamble?
The sync long block does matched filtering with the long preamble
and searches for peaks in a configurable window (sync length
parameter). Looks like even if you add 90 symbols the peak that the
block is looking for is still in the window.
Best,
Bastian