UE unable to maintain connection following attach #1494
Description
Issues have been seen with more than one UE device. I started off with no external clock and the default enb.conf and rb.conf and sib.conf and epc.conf, just minor updates for band, channel, plmn id etc. When that was not stable, I tried adding an external 10MHz clock from a R&S CMW-500, and modified the RF section of the enb.conf file accordingly.
Once the UE gets beyond the high ber RACH/ATTACH/DRB setup, it actually works quite well for many hours. But if either side disconnects or restarts, it will again struggle to connect to the cell.
I have attached full enb logs, and pcap traces from various layers.
Symptoms match those of numerous other issues for COTS phones and modems:
==== eNodeB started ===
Type <t> to view trace
Setting manual TX/RX offset to 100 samples
Setting frequency: DL=1935.0 Mhz, UL=1855.0 MHz for cc_idx=0 nof_prb=50
Starting plot for worker_id=0
Creating plot window 'srsENB PCI 1'...
QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-root'
RACH: tti=4651, cc=0, pci=1, preamble=34, offset=12, temp_crnti=0x46
User 0x46 connected
RACH: tti=9831, cc=0, pci=1, preamble=18, offset=12, temp_crnti=0x47
Disconnecting rnti=0x47.
Disconnecting rnti=0x46.
RACH: tti=9951, cc=0, pci=1, preamble=43, offset=12, temp_crnti=0x48
User 0x48 connected
RACH: tti=8971, cc=0, pci=1, preamble=25, offset=12, temp_crnti=0x49
Disconnecting rnti=0x49.
User 0x48 connected
RACH: tti=91, cc=0, pci=1, preamble=5, offset=12, temp_crnti=0x4a
Disconnecting rnti=0x4a.
User 0x48 connected
RACH: tti=6731, cc=0, pci=1, preamble=12, offset=12, temp_crnti=0x4b
Disconnecting rnti=0x4b.
User 0x48 connected
RACH: tti=4491, cc=0, pci=1, preamble=4, offset=12, temp_crnti=0x4c
Disconnecting rnti=0x4c.
User 0x48 connected
RACH: tti=5851, cc=0, pci=1, preamble=25, offset=12, temp_crnti=0x4d
Disconnecting rnti=0x4d.
User 0x48 connected
Disconnecting rnti=0x48.
RACH: tti=1661, cc=0, pci=1, preamble=5, offset=12, temp_crnti=0x4e
User 0x4e connected
Disconnecting rnti=0x4e.
RACH: tti=7651, cc=0, pci=1, preamble=43, offset=12, temp_crnti=0x4f
RACH: tti=8971, cc=0, pci=1, preamble=45, offset=12, temp_crnti=0x50
Disconnecting rnti=0x50.
RACH: tti=9121, cc=0, pci=1, preamble=31, offset=12, temp_crnti=0x51
Disconnecting rnti=0x51.
RACH: tti=9181, cc=0, pci=1, preamble=0, offset=12, temp_crnti=0x52
Disconnecting rnti=0x52.
RACH: tti=9301, cc=0, pci=1, preamble=19, offset=12, temp_crnti=0x53
Disconnecting rnti=0x53.
RACH: tti=9381, cc=0, pci=1, preamble=21, offset=12, temp_crnti=0x54
Disconnecting rnti=0x54.
User 0x4f connected
RACH: tti=6651, cc=0, pci=1, preamble=19, offset=12, temp_crnti=0x55
Disconnecting rnti=0x55.
User 0x4f connected
RACH: tti=8011, cc=0, pci=1, preamble=28, offset=12, temp_crnti=0x56
Disconnecting rnti=0x56.
User 0x4f connected
Disconnecting rnti=0x4f.
RACH: tti=7021, cc=0, pci=1, preamble=9, offset=12, temp_crnti=0x57
Disconnecting rnti=0x57.
RACH: tti=8651, cc=0, pci=1, preamble=8, offset=12, temp_crnti=0x58
User 0x58 connected
User 0x6b connected
lte 1 6b 15 0 2 0 0 25 100% | 1.3 0.1 0 0 2.1k 3 3 50% 0.0
-----------------DL----------------|-------------------------UL-------------------------
rat pci rnti cqi ri mcs brate ok nok (%) | pusch pucch phr mcs brate ok nok (%) bsr
lte 1 6b 13 0 2 0 0 43 100% | n/a -0.4 0 0 0 0 0 0% 0.0
RACH: tti=2591, cc=0, pci=1, preamble=22, offset=12, temp_crnti=0x70
Disconnecting rnti=0x70.
User 0x6b connected
lte 1 6b 15 0 1 0 0 17 100% | 1.4 1.0 0 0 304 2 2 50% 0.0
lte 1 6b n/a 0 0 0 0 0 0% | n/a n/a 0 0 0 0 0 0% 0.0
lte 1 6b n/a 0 0 0 0 0 0% | n/a n/a 0 0 0 0 0 0% 0.0
lte 1 6b n/a 0 0 0 0 0 0% | n/a n/a 0 0 0 0 0 0% 0.0
lte 1 6b 15 0 0 0 0 3 100% | n/a -0.1 0 0 0 0 0 0% 0.0
lte 1 6b n/a 0 0 0 0 0 0% | n/a n/a 0 0 0 0 0 0% 0.0
RACH: tti=9231, cc=0, pci=1, preamble=29, offset=12, temp_crnti=0x71
Disconnecting rnti=0x71.
User 0x6b connected
lte 1 6b 15 0 1 0 0 28 100% | 1.2 1.1 0 0 2.1k 3 2 40% 0.0
lte 1 6b 15 0 0 0 0 19 100% | 1.5 0.9 22 0 1.3k 1 1 50% 0.0
RACH: tti=651, cc=0, pci=1, preamble=40, offset=12, temp_crnti=0x72
Disconnecting rnti=0x72.
User 0x6b connected
lte 1 6b 12 0 0 0 0 18 100% | 1.3 0.4 0 0 304 2 2 50% 0.0
lte 1 6b n/a 0 0 0 0 0 0% | n/a n/a 0 0 0 0 0 0% 0.0
-----------------DL----------------|-------------------------UL-------------------------
rat pci rnti cqi ri mcs brate ok nok (%) | pusch pucch phr mcs brate ok nok (%) bsr
lte 1 6b 15 0 0 0 0 6 100% | n/a 3.1 0 0 0 0 0 0% 0.0
Disconnecting rnti=0x6b.
[enb_max_debug_rach_log.txt](https://github.com/user-attachments/files/21686510/enb_max_debug_rach_log.txt)
[enb_max_debug_rach_log.txt](https://github.com/user-attachments/files/21686519/enb_max_debug_rach_log.txt)
[enb_mac.zip](https://github.com/user-attachments/files/21686560/enb_mac.zip)
[enb_max_debug_rach_log.zip](https://github.com/user-attachments/files/21686558/enb_max_debug_rach_log.zip)
[enb_s1ap.zip](https://github.com/user-attachments/files/21686561/enb_s1ap.zip)
[epc.zip](https://github.com/user-attachments/files/21686559/epc.zip)
Startup and configuration with 10MHz external clock from a R&S CMW-500.
Reading configuration file /home/stevew/.config/srsran/epc.conf...
HSS Initialized.
MME S11 Initialized
MME GTP-C Initialized
MME Initialized. MCC: 0xf310, MNC: 0xf410
SPGW GTP-U Initialized.
SPGW S11 Initialized.
SP-GW Initialized.
Received S1 Setup Request.
S1 Setup Request - eNB Name: srsenb01, eNB id: 0x19b
S1 Setup Request - MCC:310, MNC:410
S1 Setup Request - TAC 7, B-PLMN 0x134001
S1 Setup Request - Paging DRX v128
Sending S1 Setup Response
Starting /usr/local/bin/srsenb with config /home/stevew/.config/srsran/enb_1tx1rx_no_mimo_50_prb.conf
# device_args: Arguments for the device driver. Options are "auto" or any string.
# device_args specicic to B210
device_args = type=b200,clock=external,num_recv_frames=64,num_send_frames=64,tx_subdev_spec=A:A,rx_subdev_spec=A:A,master_clock_rate=11.52e6
--------------------------------------------------------------------------------------
Active RF plugins: libsrsran_rf_uhd.so libsrsran_rf_soapy.so libsrsran_rf_zmq.so
Inactive RF plugins:
--- Software Radio Systems LTE eNodeB ---
Reading configuration file /home/stevew/.config/srsran/enb_1tx1rx_no_mimo_50_prb.conf...
Built in Release mode using commit ec29b0c1f on branch master.
Opening 1 channels in RF device=UHD with args=type=b200,clock=external,num_recv_frames=64,num_send_frames=64,tx_subdev_spec=A:A,rx_subdev_spec=A:A,master_clock_rate=11.52e6
Supported RF device list: UHD soapy zmq file
[INFO] [UHD] linux; GNU C++ version 11.4.0; Boost_107400; UHD_3.15.0.0-74-ge35f66e8
[INFO] [LOGGING] Opening USRP channels=1, args: type=b200,num_recv_frames=64,num_send_frames=64,tx_subdev_spec=A:A,rx_subdev_spec=A:A,master_clock_rate=11.52e6
Fastpath logging disabled at runtime.
[INFO] [UHD RF] RF UHD Generic instance constructed
[INFO] [B200] Detected Device: B210
[INFO] [B200] Operating over USB 3.
[INFO] [B200] Initialize CODEC control...
[INFO] [B200] Initialize Radio control...
[INFO] [B200] Performing register loopback test...
[INFO] [B200] Register loopback test passed
[INFO] [B200] Performing register loopback test...
[INFO] [B200] Register loopback test passed
[INFO] [B200] Asking for clock rate 11.520000 MHz...
[INFO] [B200] Actually got clock rate 11.520000 MHz.
[INFO] [UHD RF] Setting tx_subdev_spec to 'A:A'
[INFO] [UHD RF] Setting rx_subdev_spec to 'A:A'
==== eNodeB started ===
Type <t> to view trace
Setting manual TX/RX offset to 100 samples
Setting frequency: DL=1935.0 Mhz, UL=1855.0 MHz for cc_idx=0 nof_prb=50
Starting plot for worker_id=0
Creating plot window 'srsENB PCI 1'...
QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-root'
enb,conf RF settings for external 10MHz clock and
[rf]
device_name = UHD
device_args = type=b200,clock=external,num_recv_frames=64,num_send_frames=64,tx_subdev_spec=A:A,rx_subdev_spec=A:A,master_clock_rate=11.52e6
tx_gain = 70
rx_gain = 40
srate = 11.52e6
time_adv_nsamples = 100
sudo uhd_find_devices
[INFO] [UHD] linux; GNU C++ version 11.4.0; Boost_107400; UHD_3.15.0.0-74-ge35f66e8
--------------------------------------------------
-- UHD Device 0
--------------------------------------------------
Device Address:
serial: 346DCB1
name: MyB210
product: B210
type: b200
sudo uhd_usrp_probe
[INFO] [UHD] linux; GNU C++ version 11.4.0; Boost_107400; UHD_3.15.0.0-74-ge35f66e8
[INFO] [B200] Detected Device: B210
[INFO] [B200] Loading FPGA image: /usr/local/share/uhd/images/usrp_b210_fpga.bin...
[INFO] [B200] Operating over USB 3.
[INFO] [B200] Detecting internal GPSDO....
[INFO] [GPS] No GPSDO found
[INFO] [B200] Initialize CODEC control...
[INFO] [B200] Initialize Radio control...
[INFO] [B200] Performing register loopback test...
[INFO] [B200] Register loopback test passed
[INFO] [B200] Performing register loopback test...
[INFO] [B200] Register loopback test passed
[INFO] [B200] Setting master clock rate selection to 'automatic'.
[INFO] [B200] Asking for clock rate 16.000000 MHz...
[INFO] [B200] Actually got clock rate 16.000000 MHz.
_____________________________________________________
/
| Device: B-Series Device
| _____________________________________________________
| /
| | Mboard: B210
| | serial: 346DCB1
| | name: MyB210
| | product: 2
| | revision: 4
| | FW Version: 8.0
| | FPGA Version: 16.0
| |
| | Time sources: none, internal, external, gpsdo
| | Clock sources: internal, external, gpsdo
| | Sensors: ref_locked
| | _____________________________________________________
| | /
| | | RX DSP: 0
| | |
| | | Freq range: -8.000 to 8.000 MHz
| | _____________________________________________________
| | /
| | | RX DSP: 1
| | |
| | | Freq range: -8.000 to 8.000 MHz
| | _____________________________________________________
| | /
| | | RX Dboard: A
| | | _____________________________________________________
| | | /
| | | | RX Frontend: A
| | | | Name: FE-RX2
| | | | Antennas: TX/RX, RX2
| | | | Sensors: temp, rssi, lo_locked
| | | | Freq range: 50.000 to 6000.000 MHz
| | | | Gain range PGA: 0.0 to 76.0 step 1.0 dB
| | | | Bandwidth range: 200000.0 to 56000000.0 step 0.0 Hz
| | | | Connection Type: IQ
| | | | Uses LO offset: No
| | | _____________________________________________________