hackrf: gr-osmocom sink tx buffering
ewild at sysmocom.de
Wed Dec 9 15:39:55 UTC 2020
since the hackrf is half-duplex and has no timestamp support (only
continuous streaming) the buffer size was chosen at the time to provide
a reasonable tradeoff between latency and performance for higher sample
rates - I suppose you could just decrease it if that is the problem, but
there is still no way to just send something immediately, there will
always be a considerable latency between the host and the rf output.
Am 09.12.2020 um 13:23 schrieb Sebastian Böhm:
> Does anyone have any idea what could be the reason for this behavior?
> Am 01.12.2020 um 16:28 schrieb Sebastian Böhm:
>> i try to transmit 2.48 ghz radio packets (beacons) at a fixed time
>> interval (e.g. every 1 s) via hackrf using the osmocom sink in
>> gnuradio. Without exception, the beacons are all received by my
>> sniffer "golden device" hardware, but burst.
>> It seems that the packets are only transferred via USB to the hackrf
>> device hardware when the buffer with the fixed BUF_LEN 262144
>> (32*16*512) is completely filled. For my setup this are e.g. 18
>> beacon frames, which are transmitted as burst. When I look at the USB
>> interface, I can see this burst of data every 18 seconds in a full
>> USB request block (URB) of size 262144 byte. All other URBs (also of
>> size 262144 - every approx. 200us) transferred via USB are filled
>> with zeros only. So this burst behavior should be caused by gnuradio.
>> How can I achieve that the complex data of the osmocom sink's input
>> is immediately (with the next URB) transferred to the hackrf
>> hardware? Am I missing any options of the GRC module?
>> Thank You in advance!
>> Sebastian Boehm
>> Brandenburg University of Technology Cottbus - Senftenberg
>> Computer Networks Communication Systems Group
>> E-Mail: sebastian.boehm at b-tu.de <mailto:Sebastian.Boehm at b-tu.de>
>> P.O. Box: 10 13 44
>> D-03013 Cottbus
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the osmocom-sdr