Files
openairinterface5g/doc/physical-simulators.md
T
Robert Schmidt 55cebe6edf Provide add_timed_physim_test() in cmake
Add two new macros that allow to register physim tests for ctest,
including timing thresholds that should be fulfilled.

First, add_timed_physim_test() registers a new test using a helper
script RunTimedTest.cmake. This is because after test execution, we need
to analyze logs, and the recommended way to do multiple steps in one
test is via a helper cmake script:
https://cmake.org/pipermail/cmake-developers/2016-February/027816.html

Second, check_physim_threshold() adds new thresholds. It takes a text to
be parsed, and a condition (e.g., "< 20") to check for the number
following the threshold (which is assumed to be present right after the
threshold). It uses a test property to count the total number of checks
(limiting them to 10), and sets environment variables for the script.  I
initially planned to use a test property for checks, but those are only
valid in the same directory, and RunTimedTest.cmake seems to be assumed
by cmake to be "elsewhere", hence I needed to resort to environment
variables.

RunTimedTest.cmake is called through cmake with the test parameters and
checks. It re-constructs a list of checks [1], runs the test, and pipes
the log into a separate script that is passed all checks (see below).
Afterwards, it verifies that both the test and script passed.

A script analyze-timing.sh builds an awk script from the checks passed.
The script analyzes each line of the test output for the threshold, and
compares against the threshold. analyze-timing.sh returns success if all
checks passed.

[1] I did not manage to pass a "list" of checks in a single environment
variable through the check_physim_threshold(), which would be simpler.
2025-09-12 14:53:09 +02:00

204 lines
7.0 KiB
Markdown

# Physical Simulators ("Physims") User Guide
This document provides an overview and usage guide for the **physical simulators**, also referred to as **unitary
simulators** or simply **physims**, used in the OpenAirInterface (OAI) project for LTE and 5G PHY layer validation.
[[_TOC_]]
# Introduction
**Unitary simulations** are standalone test programs designed to validate individual physical layer (L1) transport or
control channels. These simulations are based on **Monte Carlo techniques**, enabling statistical evaluation of
performance metrics such as block error rate (BLER), hybrid automatic repeat request (HARQ) throughput, and decoding
accuracy under various signal conditions.
Physims are essential for:
* Debugging and evaluating new PHY code in isolation
* Regression testing
* Ensuring correctness before merging new contributions into the repository
## Examples of Simulators
| Technology | Simulators | Description |
|------------|-------------------------------------------|----------------------------------|
| 4G LTE | `dlsim`, `ulsim` | Downlink and uplink simulators |
| 5G NR | `nr_dlsim`, `nr_ulsim` | Downlink and uplink simulators |
| | `nr_dlschsim`, `nr_ulschsim` | HARQ and TB throughput tests |
| | `nr_pucchsim` | Control channel simulation |
| | `nr_pbchsim` | Broadcast channel simulation |
| | `nr_prachsim` | PRACH simulation |
| | `nr_psbchsim` | Sidelink simulation |
| Coding | `ldpctest`, `polartest`, `smallblocktest` | LDPC, Polar, and other FEC tests |
### Source Locations
* 4G PHY simulators: `openair1/SIMULATION/LTE_PHY/`
* 5G PHY simulators: `openair1/SIMULATION/NR_PHY/`
* Coding unit tests: `openair1/PHY/CODING/TESTBENCH/`
Example:
```bash
# 5G Downlink simulator
openair1/SIMULATION/NR_PHY/dlsim.c
```
# How to Run Simulators Using `ctest`
## Option 1: Using CMake
```bash
cd openairinterface5g
mkdir build && cd build
cmake .. -GNinja -DENABLE_PHYSIM_TESTS=ON
ninja tests
ctest
```
## Option 2: Using the `build_oai` script
This method simplifies the process by automatically building the simulators with ctest support.
```bash
cd openairinterface5g/cmake_targets
./build_oai --ninja --phy_simulators
cd ran_build/build
ctest
```
# `ctest` Usage Tips
## Useful Options
Use the following options to customize test execution:
| Option | Description |
|------------------|------------------------------------------------------|
| `-R <regex>` | Run tests matching the regex pattern (by name) |
| `-L <regex>` | Run tests with labels matching the regex pattern |
| `-E <regex>` | Exclude tests matching the regex pattern (by name) |
| `-LE <regex>` | Exclude tests with labels matching the regex pattern |
| `--print-labels` | Display all available test labels |
| `-j <jobs>` | Run tests in parallel using specified number of jobs |
For the complete list of `ctest` options, refer to the manual:
```bash
man ctest
```
## Example
```bash
# Run only NR ULSCH simulator tests, in parallel
ctest -L nr_ulsch -j 4
```
# Adding a New Physim Test
To define a new test or modify existing ones, update the following file:
```
openair1/SIMULATION/tests/CMakeLists.txt
```
## `add_physim_test()`
Use the `add_physim_test()` macro with the following arguments:
add_physim_test(<test_name> <test_description> <test_exec> <test_options>)
where:
- `<test_name>` can be any name, but the canonical, historical format is to put
it `physim.<gen>.<test_exec>.test<XYZ>` where `<gen>` is 4g/5g, and `<XYZ>`
is an increasing number
- `<test_description>` is a human-readable description of the test
- `<test_exec> <test_options>` is the test invocation, where `<test_exec>` must
be a target built by OAI cmake (e.g., `nr_prachsim`), followed by any options.
For instance, a PRACHsim looks like this:
add_physim_test(physim.5g.nr_prachsim.test8 "15kHz SCS, 25 PRBs" nr_prachsim -a -s -30 -n 300 -p 99 -R 25 -m 0)
These tests are run automatically as part of the following
pipelines: [RAN-PhySim-Cluster-4G](https://jenkins-oai.eurecom.fr/job/RAN-PhySim-Cluster-4G/) and [RAN-PhySim-Cluster-5G](https://jenkins-oai.eurecom.fr/job/RAN-PhySim-Cluster-5G/)
## `add_timed_physim_test()`
Use the `add_timed_physim_test()` macro to add a test the same way as with
`add_physim_test()` above. Additionally, it allows to check for thresholds with
`check_threshold()`:
check_threshold(<test_name> <threshold> <condition>)
where:
- `<test_name>` is any test that must have been added with
`add_timed_physim_test()`
- `<threshold>` is a threshold to check for, e.g., `PHY tx proc`, and
- `<condition>` a condition to check, e.g. `< 200`
There are two convenience functions to simplify the use of `check_threshold()`:
check_threshold_range(<test_name> <threshold> LOWER <lower> UPPER <upper>)
check_threshold_variance(<test_name> <threshold> AVG <avg> ABS_VAR <abs_var>)
where
- `<lower>` and `<upper>` are a lower and upper threshold, respectively, where
either one or both variables can be provided, and
- `<avg>` and `<abs_var>` are average and the variation in absolute numbers
(not a percentage!) can be provided.
Both functions internally use `check_threshold()`.
Thus upon execution of the test, the test will be run, but additionally ctest
will check for a match of `PHY tx proc <NUMBER>` (where `<NUMBER> is of format
`[0-9]+(\.[0-9]+)?`), and a matching number will be checked against condition
`< 200`.
For instance, this could look like this:
add_timed_physim_test(physim.5g.nr_dlsim.test3 "Some description" nr_dlsim -P)
check_physim_threshold(physim.5g.nr_dlsim.test3 "DLSCH encoding time" "< 50")
### How to rerun failed CI tests using `ctest`
Ctest automatically logs the failed tests in LastTestsFailed.log. This log is archived in
the CI artifacts and can be reused locally to rerun only those failed tests.
```bash
# 1. Navigate to the build directory, build physims
cd ~/openairinterface5g/build
cmake .. -GNinja -DENABLE_PHYSIM_TESTS=ON && ninja tests
# 2. Create ctest directory structure
ctest -N --quiet
# 3. Unzip the test logs artifact from the CI run
unzip /path/to/test_logs_123.zip
# 4. Copy the LastTestsFailed.log file to the expected location
cp /path/to/test_logs_123/test_logs/LastTestsFailed.log ./Testing/Temporary/
# 5. Rerun only the failed tests using ctest
ctest --rerun-failed
```
# Legacy Bash Autotest (Deprecated)
> **Note:** Autotest script, configuration, and documentation, are no longer maintained.
For legacy support or archival purposes, you can still find this implementation by checking out the historical tag:
```bash
git checkout 2025.w18
```
# Unmaintained tests
A few tests dedicated to 4G are unmaintained:
- `mbmssim`
- `scansim`
- all simulators of format `www-tmyyyy` (for instance, `dlsim_tm4`)