Hi there, In general, your problem as you describe it is not a known issue.
sometimes odd problems show up from a bad clock. if your bts has not been calibrated in a long time, calibrate it; like one thing less to worry about. A sysmobts clock is generally good, no need to worry about GPS. Though once i had a broken ocxo, but then the bts did nothing much at all anymore. Calibration is a special tool you run once to determine the best value for your oscillator (oven controlled). So you tale your cell offline and then you can calibrate against any band your sysmobts supports. update the config with the new value and back to operation. it is described in the sysmobts manual. The uplink measurements should not be related to your phone's idle status. I would look at first the bssmap traffic and then the abis_rsl around the end of that call, with wireshark... you could record that and share it, e.g. attached to an osmocom.org issue. Also interesting are the bsc and then bts logs to see if anything times out or errors around such event. it's hard to say from the distance. pcap and logs might let us help you better. ~N
