Every other 5G lab runs UERANSIM — which has no PHY at all. It fabricates NAS and RRC messages over UDP: no OFDM, no PRACH, no HARQ, no scheduler, nothing to measure. This one runs a real srsRAN gNB and a real srsUE exchanging genuine baseband samples into a real Open5GS core — so you can watch a preamble land, a retransmission recover, and an MCS fall as the channel degrades.
the difference
Both print “registration complete”. Only one of them produces a signal.
every other 5G lab
this lab
preamble 0 → ra-rnti 0x39 → c-rnti 0x4601.coverage
The gNB runs a disaggregated CU‑CP / CU‑UP / DU, so F1 and E1 are real protocol exchanges here — not diagrams of one.
evidence, not claims
Unedited output from the machine this lab runs on.
# random access — a real preamble, not a function call [MAC-NR] Random Access Transmission: prach_occasion=0, preamble_index=0, ra-rnti=0x39 [MAC-NR] Random Access Complete. c-rnti=0x4601, ta=0 # the core's own view [amf] INFO: [imsi-999700000000001] Registration complete [smf] INFO: UE SUPI[imsi-999700000000001] DNN[internet] IPv4[10.45.0.4] # live physical layer — per slot, with real measurements [PHY] PUCCH: rnti=0x4601 format=2 prb=[7, 8) symb=[4, 6) csi1=1111 sinr=11.3dB # and it is a real network — traffic over the 5G bearer $ ip netns exec ue1 ping 8.8.8.8 3 packets transmitted, 3 received, 0% packet loss, rtt avg 34.0 ms $ ip netns exec ue1 curl https://www.google.com HTTPS 200 0.296 s dl=82985 B
what you actually do
PSS/SSS correlation, MIB decode, SIB1 acquisition — on the real grid, before any message exists.
Inject noise and watch MCS fall, BLER climb, HARQ retransmissions spike and throughput collapse — live.
A single power-on, time-aligned from PRACH through F1AP, E1AP, NGAP and the core's HTTP/2 SBI calls.
Genuine UPER-encoded RRC decoded to the bit, cross-referenced to the 3GPP clause that defines it.
From the UE socket through PDCP ciphering, RLC, MAC, the air, GTP-U on N3, the UPF, and out.
RAND, AUTN, XRES*, K_AUSF on the wire — with the K and OPc that produced them, so the maths is checkable.
the machine
Nothing here is illustrative — this is the deployed cell.
Attach a real UE to a real gNB, and watch the whole network answer.
CafeTele · Real 5G RAN + Core Lab · srsRAN × Open5GS