diff --git a/doc/README.md b/doc/README.md
index 40f838750a..8ed2d8896b 100644
--- a/doc/README.md
+++ b/doc/README.md
@@ -118,6 +118,7 @@ Some directories under `radio` contain READMEs:
 - [IQPlayer](../radio/iqplayer/DOC/iqrecordplayer_usage.md), and [general documentation](./iqrecordplayer_usage.md)
 - [fhi_72](../radio/fhi_72/README.md)
 - [vrtsim](../radio/vrtsim/README.md)
+- [rf_emulator](../radio/emulator/README.md)
 
 The other SDRs (AW2S, LimeSDR, ...) have no READMEs.
 
diff --git a/radio/emulator/README.md b/radio/emulator/README.md
new file mode 100644
index 0000000000..b3b58ba6a7
--- /dev/null
+++ b/radio/emulator/README.md
@@ -0,0 +1,25 @@
+# RF emulator library
+
+The RF emulator is a simple network stack terminator on the RF side.  
+It is meant to run the network stack without real radio and without RF simulation.
+It simply drops TX signal and generate noise as an RX signal.
+It can be used in `phy-test` mode to simply benchmark the network stack in a determined scenario.  
+It synchronizes the network stack on the real time clock of the host to guarantee a realistic behavior of the network stack.
+It detects and report late samples reads and writes to assess the real time behavior of the network stack.
+
+## Building
+
+`librf_emulator.so` is built by default by the `build_oai.sh` script.  
+It is then located in the root build directory (usually `cmake_targets/ran_build/build`).
+
+## Usage
+
+### Enabling `rf_emulator`
+
+Use the option `--device.name rf_emulator` of the softmodem to use the RF emulator.
+
+### Options
+
+Two options are available to configure the RF emulator:
+* `--rf_emulator.enable_noise <enable>` Enables (enable = 1) or disables (enable = 0) noise generation on RX. By default noise generation is enabled.
+* `--rf_emulator.noise_level_dBFS <noise_level>` Sets the level of noise generated in dB. If omitted no noise is generated.