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Alexander Huemer alexander.huemer at xx.vuHi! On Wed, Dec 27, 2017 at 07:00:44AM +0100, Sylvain Munaut wrote: > osmo-trx needs devices that support hardware timestamping of packets (TX/RX). > > The URSP1 UHD driver doesn't support that. All the timestamps are > 'faked' in software. > That's because the FPGA image for USRP1 doesn't support hardware timestamps. > > OpenBTS used a custom FPGA image where hardware timestamping support > was added and they used libusrp (and not UHD) because it was a lower > layer API and that let them access the raw content of the data packets > sent by the USRP. That's needed because with that new FPGA image, the > content of those packets is no longer just samples, but it now has a > header with the timestamps and some flags that needs to be intepreted > to generate the timestamping and removed before converting the > samples. > > A long time ago I wanted to implement support for that FPGA image into > UHD ... and then when I looked into UHD work, I gave up ... (basically > I could never figure out _HOW_ UHD works). Thanks for the great explanation! So, in theory it would be possible to make osmo-trx work with a USRP1 via UHD, though nobody has done (yet) what you described above. Kind regards, -Alex -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 819 bytes Desc: Digital signature URL: <http://lists.osmocom.org/pipermail/openbsc/attachments/20180118/29d2246e/attachment.bin>