"Osmo-USRP": combining OpenBTS and Osmocom

Hey all, I've been working on connecting OpenBTS and osmo-bts ever since Harald formed the openbts-osmo repo (http://cgit.osmocom.org/cgit/openbts-osmo) and left me with a nice muxer framework and L1-L2 separation. I've named it Osmo-USRP but you can call it openbts-osmo or TrueBTS or whatever; it's not a big deal. Unfortunately I'm running short on time for completing my MS research, so testing is nowhere near complete but I figured I'd let the public users help me out a bit here if they want to try it out. Many thanks to Tom Tsou for helping me weed out bugs and test too. I've only scratched the surface of testing it with USRP1, USRP2, single vs. multiple PCs (Ubuntu and Fedora), and multiple BTSs. I've been able to get a stable network of 1 and 2 BTSs across 2 PCs with multiple MSs camped, and voice calls and SMS working. There seem to be a few fickle and unknown issues depending on which PC/Linux flavors/time of day I tested, and of course sometimes it will work for a certain MS but not another. Sometimes MSs won't location update to the network, or will hit errors when establishing a call; in the usual case, this won't even free the TCH so if resources run out the BTS must be rebooted. Just a few issues to name here, and I'm sure there are more out there. The current focus of work (when I can find time) is implementing handover between cells. I'm not even sure if osmo-bts and OpenBTS contain all the supporting functionality for handover (OpenBSC does though). The MSs correctly send SACCH meas reports, the BSC detects and decides to handover, and the TCH is activated, but I think the Handover Command is getting lost in the BTS or the MS Handover Accept bursts are being processed. The newly activated osmo-bts instance segfaults somewhere in LAPDm. I haven't had time lately to pinpoint the error, but just wanted to update on the current status of that. Also, multiple configuration files are needed because I have network parameters hard-coded (just for ease), which is elaborated some in the wiki. I ran into a segfault/bug trying to implement passing in config parameters from OpenBSC, and gave up to pursue more critical aspects of the project. Github repo: https://github.com/tacooper (first release tag for Osmo-USRP = v0.1) README/Guide: https://github.com/tacooper/Osmo-USRP/downloads (issues, configuration, and example setup for single/multi-BTS networks) If you'd like to help out by testing or even working on this project, it is much appreciated, even if only to help me grow my understanding of GSM networks through discussion. Thanks! Tom Cooper