srsRAN FATAL ERROR: Invalid nof. SSB per RACH occasion value 0.25 #1426
Description
I strictly fellowed the steps in the Multi-UE Emulation section of https://docs.srsran.com/projects/project/en/latest/tutorials/source/srsUE/source/index.html website.I configured the core network and gnb using the configuration files on the website.However,the following error occurred after I started the gnb.
sudo ./gnb -c ./gnb_zmq.yaml
--== srsRAN gNB (commit d2f4b70dda) ==--
Lower PHY in executor sequential baseband mode.
Available radio types: zmq.
Cell pci=1, bw=10 MHz, 1T1R, dl_arfcn=368500 (n3), dl_freq=1842.5 MHz, dl_ssb_arfcn=368410, ul_freq=1747.5 MHz
N2: Connection to AMF on 10.53.1.2:38412 completed
srsRAN FATAL ERROR: Invalid nof. SSB per RACH occasion value 0.25
Aborted
Below is the gnb_zmq.yaml provided in the official documnt.
# This configuration file example shows how to configure the srsRAN Project gNB to allow srsUE to connect to it.
# This specific example uses ZMQ in place of a USRP for the RF-frontend, and creates an FDD cell with 10 MHz bandwidth.
# To run the srsRAN Project gNB with this config, use the following command:
# sudo ./gnb -c gnb_zmq.yaml
cu_cp:
amf:
addr: 10.53.1.2 # The address or hostname of the AMF.
port: 38412
bind_addr: 10.53.1.1 # A local IP that the gNB binds to for traffic from the AMF.
supported_tracking_areas:
- tac: 7
plmn_list:
- plmn: "00101"
tai_slice_support_list:
- sst: 1
inactivity_timer: 7200 # Sets the UE/PDU Session/DRB inactivity timer to 7200 seconds. Supported: [1 - 7200].
ru_sdr:
device_driver: zmq # The RF driver name.
device_args: tx_port=tcp://127.0.0.1:2000,rx_port=tcp://127.0.0.1:2001,base_srate=11.52e6 # Optionally pass arguments to the selected RF driver.
srate: 11.52 # RF sample rate might need to be adjusted according to selected bandwidth.
tx_gain: 75 # Transmit gain of the RF might need to adjusted to the given situation.
rx_gain: 75 # Receive gain of the RF might need to adjusted to the given situation.
cell_cfg:
dl_arfcn: 368500 # ARFCN of the downlink carrier (center frequency).
band: 3 # The NR band.
channel_bandwidth_MHz: 10 # Bandwith in MHz. Number of PRBs will be automatically derived.
common_scs: 15 # Subcarrier spacing in kHz used for data.
plmn: "00101" # PLMN broadcasted by the gNB.
tac: 7 # Tracking area code (needs to match the core configuration).
pdcch:
common:
ss0_index: 0 # Set search space zero index to match srsUE capabilities
coreset0_index: 6 # Set search CORESET Zero index to match srsUE capabilities
dedicated:
ss2_type: common # Search Space type, has to be set to common
dci_format_0_1_and_1_1: false # Set correct DCI format (fallback)
prach:
prach_config_index: 1 # Sets PRACH config to match what is expected by srsUE
total_nof_ra_preambles: 64 # Sets number of available PRACH preambles
nof_ssb_per_ro: 1 # Sets the number of SSBs per RACH occasion.
nof_cb_preambles_per_ssb: 64 # Sets the number of contention based preambles per SSB.
pdsch:
mcs_table: qam64 # Sets PDSCH MCS to 64 QAM
pusch:
mcs_table: qam64 # Sets PUSCH MCS to 64 QAM
log:
filename: /tmp/gnb.log # Path of the log file.
all_level: info # Logging level applied to all layers.
hex_max_size: 0
pcap:
mac_enable: false # Set to true to enable MAC-layer PCAPs.
mac_filename: /tmp/gnb_mac.pcap # Path where the MAC PCAP is stored.
ngap_enable: false # Set to true to enable NGAP PCAPs.
ngap_filename: /tmp/gnb_ngap.pcap # Path where the NGAP PCAP is stored.
Then I input cat /tmp/gnb.log | head -n 100to look the log
2025-11-24T14:31:30.348049 [GNB ] [I] Built in Release mode using commit d2f4b70dda on branch main
2025-11-24T14:31:30.349083 [CONFIG ] [I] Input configuration (only non-default values):
log:
filename: /tmp/gnb.log
all_level: info
hex_max_size: 0
cu_cp:
inactivity_timer: 7200
amf:
addr: 10.53.1.2
port: 38412
bind_addr: 10.53.1.1
supported_tracking_areas: "tac: 7\nplmn_list:\n - plmn: 00101\n tai_slice_support_list:\n - sst: 1"
pcap:
ngap_filename: /tmp/gnb_ngap.pcap
ngap_enable: false
mac_filename: /tmp/gnb_mac.pcap
mac_enable: false
cell_cfg:
dl_arfcn: 368500
band: 3
common_scs: 15
channel_bandwidth_MHz: 10
plmn: 00101
tac: 7
pdcch:
common:
coreset0_index: 6
ss0_index: 0
dedicated:
dci_format_0_1_and_1_1: false
ss2_type: common
pdsch:
mcs_table: qam64
pusch:
mcs_table: qam64
prach:
prach_config_index: 1
total_nof_ra_preambles: 64
nof_ssb_per_ro: 1
nof_cb_preambles_per_ssb: 64
ru_sdr:
srate: 11.52
device_driver: zmq
device_args: tx_port=tcp://127.0.0.1:2000,rx_port=tcp://127.0.0.1:2001,base_srate=11.52e6
tx_gain: 75
rx_gain: 75
2025-11-24T14:31:30.954112 [GNB ] [W] CPU0 scaling governor is not set to performance, which may hinder performance. You can set it to performance using the "srsran_performance" script
2025-11-24T14:31:30.954121 [GNB ] [W] CPU1 scaling governor is not set to performance, which may hinder performance. You can set it to performance using the "srsran_performance" script
2025-11-24T14:31:30.954128 [GNB ] [W] CPU2 scaling governor is not set to performance, which may hinder performance. You can set it to performance using the "srsran_performance" script
2025-11-24T14:31:30.954134 [GNB ] [W] CPU3 scaling governor is not set to performance, which may hinder performance. You can set it to performance using the "srsran_performance" script
2025-11-24T14:31:30.954140 [GNB ] [W] CPU4 scaling governor is not set to performance, which may hinder performance. You can set it to performance using the "srsran_performance" script
2025-11-24T14:31:30.954146 [GNB ] [W] CPU5 scaling governor is not set to performance, which may hinder performance. You can set it to performance using the "srsran_performance" script
2025-11-24T14:31:30.954152 [GNB ] [W] CPU6 scaling governor is not set to performance, which may hinder performance. You can set it to performance using the "srsran_performance" script
2025-11-24T14:31:30.954158 [GNB ] [W] CPU7 scaling governor is not set to performance, which may hinder performance. You can set it to performance using the "srsran_performance" script
2025-11-24T14:31:30.954164 [GNB ] [W] CPU8 scaling governor is not set to performance, which may hinder performance. You can set it to performance using the "srsran_performance" script
2025-11-24T14:31:30.954170 [GNB ] [W] CPU9 scaling governor is not set to performance, which may hinder performance. You can set it to performance using the "srsran_performance" script
2025-11-24T14:31:30.954176 [GNB ] [W] CPU10 scaling governor is not set to performance, which may hinder performance. You can set it to performance using the "srsran_performance" script
2025-11-24T14:31:30.954182 [GNB ] [W] CPU11 scaling governor is not set to performance, which may hinder performance. You can set it to performance using the "srsran_performance" script
2025-11-24T14:31:30.954189 [GNB ] [W] DRM KMS polling is enabled, which may hinder performance. You can disable it using the "srsran_performance" script
2025-11-24T14:31:30.955046 [CONFIG ] [I] Worker pool "main_pool" instantiated with #workers=5, task_queue_size=2048, backoff_period=50us and priority=96.
2025-11-24T14:31:30.969288 [GTPU ] [I] GTP-U demux. queue_size=2046 batch_size=256 warn_on_drop=false test_mode=false
2025-11-24T14:31:30.969428 [GTPU ] [I] Tunnel added. teid=0x000000
2025-11-24T14:31:31.224792 [DU-MNG ] [I] The upper-bound on the number of UEs supported by cell {pci=1, du_cell_index=0} is 160 (the actual number might be lower than that). This is determined by the lowest of the following limits: SR (160), CSI (160) and SRS (n/a).
2025-11-24T14:31:31.224951 [DU ] [I] DU created successfully
2025-11-24T14:31:31.224958 [DU ] [I] O-DU created successfully
2025-11-24T14:31:31.238635 [zmq:tx:0:0] [I] Binding to address tcp://127.0.0.1:2000.
2025-11-24T14:31:31.251919 [zmq:rx:0:0] [I] Connecting to address tcp://127.0.0.1:2001.
2025-11-24T14:31:31.503711 [GNB ] [I] SSB derived parameters for cell: 1, band: 3, dl_arfcn:368500, nof_crbs: 52 scs:15kHz, ssb_scs:15kHz:
- SSB offset pointA:13
- k_SSB:6
- SSB arfcn:368410
- Coreset index:6
- Searchspace index:0
2025-11-24T14:31:31.503752 [GNB ] [I] Starting CU-CP...
2025-11-24T14:31:31.503927 [CU-CP ] [I] N2: Connection to AMF on 10.53.1.2:38412 was established
2025-11-24T14:31:31.503995 [NGAP ] [I] Tx PDU: NGSetupRequest
2025-11-24T14:31:31.507861 [NGAP ] [I] Rx PDU: NGSetupResponse
2025-11-24T14:31:31.507884 [CU-CP ] [I] Connected to AMF. Supported PLMNs: 00101
2025-11-24T14:31:31.507898 [GNB ] [I] CU-CP started successfully
2025-11-24T14:31:31.507902 [CU-UP ] [I] CU-UP starting...
2025-11-24T14:31:31.507946 [CU-CP ] [I] Added TNL connection to CU-UP 0
2025-11-24T14:31:31.507962 [CU-UP-E1] [I] Sending E1SetupRequest
2025-11-24T14:31:31.507967 [CU-UP-E1] [I] Tx PDU tid=0: GNB-CU-UP-E1SetupRequest
2025-11-24T14:31:31.507975 [CU-CP-E1] [I] Rx PDU tid=0: GNB-CU-UP-E1SetupRequest
2025-11-24T14:31:31.507980 [CU-CP-E1] [I] Tx PDU tid=0: GNB-CU-UP-E1SetupResponse
2025-11-24T14:31:31.507984 [CU-UP-E1] [I] Rx PDU tid=0: GNB-CU-UP-E1SetupResponse
2025-11-24T14:31:31.507985 [CU-UP-E1] [I] "E1AP CU-UP Setup Procedure" finalized
2025-11-24T14:31:31.507991 [CU-UP ] [I] CU-UP started successfully
2025-11-24T14:31:31.507994 [DU ] [I] Starting DU...
2025-11-24T14:31:31.507994 [DU ] [I] Starting DU-High...
2025-11-24T14:31:31.507996 [DU-MNG ] [I] DU manager starting...
2025-11-24T14:31:31.508059 [CU-CP ] [I] Added TNL connection to DU 0
2025-11-24T14:31:31.508064 [APP ] [E] Emergency flush of the logger
The nof_ssb_per_ro is indeed 1,not 0.25.I don't konw how to solve this bug.