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Issues Following PRS Tutorial with RFSim – FR2 gNB Startup Fails, FR1 Data Extraction from Tracer Not Working

Hello,

I encountered a couple of issues while trying to follow the Tutorial for PRS while using RFSim.

  • FR2 Setup Failure:

    Attempting to set up a test connection in FR2 fails entirely. The gNB does not start when using the command provided in the tutorial. It results in the following error: (See log below)

    So I think the tutorial is out of date, or just has mistakes that I could not find. I used a fresh OAI install with the newest develop. Thanks in advance for your help!

  • FR1 Dump Extraction Issue:

    For FR1, the setup (one gnb, one UE) does start successfully. However, when I try to extract the dumped data as described in the tutorial, it does not work. My extracted data folder after the following step "Extract PRS channel estimates" is simply empty. Using the help command did not help either.

    I followed the steps exactly, using a fresh OAI install on the latest develop branch, but still encountered this issue. Could someone please try to replicate that?

Update: See below, make in the tracer folder does not run completly, which might explain it.

Best regards,

sudo ./nr-softmodem -O ../../../targets/PROJECTS/GENERIC-NR-5GC/CONF/gnb0.prs.band261.fr2.64PRB.usrpx310.conf --noS1 --rfsim --phy-test
CMDLINE: "./nr-softmodem" "-O" "../../../targets/PROJECTS/GENERIC-NR-5GC/CONF/gnb0.prs.band261.fr2.64PRB.usrpx310.conf" "--noS1" "--rfsim" "--phy-test" 
[CONFIG] function config_libconfig_init returned 0
[UTIL]   running in phy-test mode (--phy-test)
[OPT]   OPT disabled
[HW]   Version: Branch: develop Abrev. Hash: b5f7d22c02 Date: Tue Apr 8 12:20:05 2025 +0000
[GNB_APP]   Initialized RAN Context: RC.nb_nr_inst = 1, RC.nb_nr_macrlc_inst = 1, RC.nb_nr_L1_inst = 1, RC.nb_RU = 1, RC.nb_nr_CC[0] = 1
[NR_PHY]   Initializing gNB RAN context: RC.nb_nr_L1_inst = 1 
[NR_PHY]   Registered with MAC interface module (0x585ead0fe6f0)
[NR_PHY]   Initializing NR L1: RC.nb_nr_L1_inst = 1
[NR_PHY]   L1_RX_THREAD_CORE -1 (15)
[NR_PHY]   TX_AMP = 519 (-36 dBFS)
[PHY]   -----------------------------------------
[PHY]   PRS Config for gNB_id 0 @ 0x74c8dcdb26fc
[PHY]   -----------------------------------------
[PHY]   NumPRSResources 	8
[PHY]   PRSResourceSetPeriod 	[80, 2]
[PHY]   NumRB 			64
[PHY]   RBOffset 		0
[PHY]   CombSize 		4
[PHY]   PRSResourceRepetition 	1
[PHY]   PRSResourceTimeGap 	1
[PHY]   MutingBitRepetition 	1
[PHY]   SymbolStart 		[8, 8, 8, 8, 8, 8, 8, 8] 
[PHY]   NumPRSSymbols 		[6, 6, 6, 6, 6, 6, 6, 6] 
[PHY]   REOffset 		[0, 0, 0, 0, 0, 0, 0, 0] 
[PHY]   PRSResourceOffset 	[0, 10, 20, 30, 40, 50, 60, 70] 
[PHY]   NPRS_ID 		[0, 1, 2, 3, 4, 5, 6, 7] 
[PHY]   MutingPattern1 	       ][
[PHY]   MutingPattern2 	       ][
[PHY]   -----------------------------------------
[GNB_APP]   pdsch_AntennaPorts N1 1 N2 1 XP 1 pusch_AntennaPorts 1
[GNB_APP]   minTXRXTIME 6
[GNB_APP]   SIB1 TDA 1
[GNB_APP]   CSI-RS 0, SRS 0, 256 QAM may be on, delta_MCS off, maxMIMO_Layers -1, HARQ feedback enabled, num DLHARQ:16, num ULHARQ:16
[NR_MAC]   No RedCap configuration found
[GNB_APP]   sr_ProhibitTimer 0, sr_TransMax 64, sr_ProhibitTimer_v1700 0, t300 400, t301 400, t310 2000, n310 10, t311 3000, n311 1, t319 400
[NR_MAC]   Candidates per PDCCH aggregation level on UESS: L1: 0, L2: 2, L4: 0, L8: 0, L16: 0
[RRC]   Read in ServingCellConfigCommon (PhysCellId 0, ABSFREQSSB 2071241, DLBand 261, ABSFREQPOINTA 2070833, DLBW 64,RACH_TargetReceivedPower -118
[RRC]   absoluteFrequencySSB 2071241 corresponds to 27524520000 Hz
[NR_MAC]   TDD period index = 3, based on the sum of dl_UL_TransmissionPeriodicity from Pattern1 (1.250000 ms) and Pattern2 (0.000000 ms): Total = 1.250000 ms
[UTIL]   threadCreate() for MAC_STATS: creating thread with affinity ffffffff, priority 2
[RLC]   RLC UM Bi-directional Bearer configuration selected 
[PDCP]   added drb 1 to UE ID 4660
[RLC]   Added DRB to UE 4660
[NR_MAC]   PUSCH Target 200, PUCCH Target 200, PUCCH Failure 10, PUSCH Failure 10
[NR_PHY]   Copying 0 blacklisted PRB to L1 context

Assertion (bw_index >= 0 && bw_index <= (sizeof(bandwidth_index_to_mhz)/sizeof(*(bandwidth_index_to_mhz)))) failed!
In get_supported_bw_mhz() /home/inets/oai-prs-04/common/utils/nr/nr_common.c:403
Bandwidth index -1 is invalid

Exiting execution
/home/inets/oai-prs-04/common/utils/nr/nr_common.c:403 get_supported_bw_mhz() Exiting OAI softmodem: _Assert_Exit_
Edited by Oliver Schirrmacher