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