coRAN LABS
Integrated Sensing and Communication

ISAC

Sensing on the signals your network already sends. An open-source 5G NR testbed that turns a mobile network into a sensor, with no radar hardware and no extra spectrum.

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What ISAC is

Integrated Sensing and Communication, on standard 5G

Integrated Sensing and Communication turns a mobile network into a sensor. The same base station that carries traffic also detects what moves around it, with no radar hardware and no extra spectrum.

ISAC node nrUE is an open-source testbed for exactly that. An OCUDU RAN transmits ordinary 5G downlink reference signals; a second antenna on the same mast listens for the reflections and turns them into a live range-Doppler map. The sensing rides on CSI-RS, the reference signals every 5G cell already transmits, so the waveform stays fully standards-compliant and any deployed cell becomes a potential sensor. The cost is one extra receive antenna, not a redesign.

No new spectrum

Sensing is parasitic on CSI-RS the cell already sends.

NR-compliant

Nothing added to the air interface; fully 3GPP-compliant.

No radar hardware

One extra receive antenna, off-the-shelf SDR, no redesign.

Open source

UE tap, wire format and receiver published; reproducible.

ISAC live range-Doppler sensing demo

Architecture

Pseudo-monostatic ISAC on 5G NR CSI-RS, sensing parasitic on the downlink

ISAC architecture: RF chain, monostatic geometry, receiver chain and datasheet

The RF chain runs OCUDU gNB → LiteON O-RAN RU → target → panel antenna → USRP X410 → nr-uesoftmodem → the range-Doppler receiver. The dominant signal is the direct coupling between the two co-located antennas, and every processing stage is built to fight it.

How it works

Delay gives distance. Frequency shift gives speed. Both come from signals the network already sends.

1
The cell transmits reference signals
An OCUDU RAN sends standard 3GPP downlink CSI-RS, the same signals handsets use to measure the channel. Nothing is added to the air interface.
2
Reflections return, shifted
Signals reflect off whatever is in front of the mast and arrive at a receive antenna slightly later and slightly shifted in frequency. The delay encodes distance; the shift encodes speed.
3
The UE taps its own channel estimate
The receiver is an OpenAirInterface 5G UE with a small tap added. It already computes a least-squares channel estimate for every reference-signal transmission. The tap copies that estimate and streams it off-box over UDP. No extra PHY processing.
4
A processing chain renders the map
A signal-processing chain separates moving targets from the static room using MTI, Doppler, CA-CFAR and an M-of-N tracker, then renders a live range-Doppler map.
The physics
R = c · τ / 2
range from round-trip delay
v = λ · f_d / 2
velocity from Doppler shift

The sensing observable is the least-squares channel estimate the UE already computes. The tap copies estimates that exist anyway. It adds no PHY processing.

The testbed

Off-the-shelf hardware throughout. Every part is commercially available or open source.

OCUDU RAN + LiteON RU

An OCUDU RAN drives a LiteON O-RAN radio unit over DPDK fronthaul, on band n78 at 100 MHz. The transmit side is a standard 5G cell.

ISAC panel antenna + USRP X410

The ISAC panel antenna and the RU share one mast. A USRP X410 SDR feeds the UE as the sensing receiver.

Shared clock & OAI UE

A Falcon X GM supplies a common clock and time reference so transmitter and receiver stay coherent. The receiver is an OpenAirInterface UE with the sensing tap.

Labeled ISAC testbed: LiteON radio unit, ISAC panel antenna, USRP X410, Falcon X GM, OAI UE and OCUDU RAN
ISAC testbed deployed: coRAN LABS panel antenna on the mast beside the LiteON radio unit and the server rack
ISAC testbed in the field, sensing a person walking across the terrace

See it in action

A walkthrough of the ISAC testbed sensing live on 5G NR reference signals.

ISAC demo · sensing on 5G NR

What Release 1.0 does

A motion and Doppler sensor. 100 MHz carrier in band n78, measured against the repo's own code and recordings.

1.525 m
Range resolution
c / (2·B)
416 m
Unambiguous range
c / (2·Δf)
20 ms
Update rate
CSI-RS / TRS
±1.09 m/s
Unambiguous velocity
default map
±43.4 m/s
Velocity with --unfold
0.5 ms baseline
0.068 m/s
Velocity resolution
CPI 32 · 0.64 s
Open source

Reproducible on standard hardware

The UE tap, the streaming format and the full receiver are published under the same licence as OpenAirInterface, along with the tooling used to verify them. It is a fork of Duranta OpenAirInterface that adds two new source files and 17 lines of integration. Everything else is stock upstream.

Sense with the network you already have

Explore the open-source ISAC testbed, or talk to us about integrated sensing on your 5G deployment.