mirror of
https://gitlab.eurecom.fr/oai/openairinterface5g.git
synced 2026-07-13 04:30:28 +00:00
438de535fa
- make internal links relative where applicable - delete link to the wiki, as the documentation is in the main repo, not the wiki - remove some "example in oai code" as the examples either don't exist, or are not in that place, and we can reasonably expect people to grep Signed-off-by: Robert Schmidt <robert.schmidt@openairinterface.org>
73 lines
3.9 KiB
Markdown
73 lines
3.9 KiB
Markdown
<!-- SPDX-License-Identifier: CC-BY-4.0 -->
|
|
|
|
# I/Q record-replay
|
|
## using the iq record-replay
|
|
|
|
This feature provides I/Q record-replay as initially presented in the [4th OAI workshop for LTE](https://www.openairinterface.org/docs/workshop/4_OAI_Workshop_20171107/Talks/MONGAZON_Nokia-Bell-Labs-OAI-IQ.pdf)
|
|
The current implementation has been temporarily disrupted for LTE and only works for 5G SA
|
|
nr-uesoftmodem executable.
|
|
|
|
The I/Q record-replay feature is briefly described hereafter, it allows you to:
|
|
|
|
* record slots received by the USRP board in a file while the system is operating.
|
|
For example you can record a full nrUE connection/traffic/disconnection sequence.
|
|
Today the OAI USRP device is the only one supporting the recording feature.
|
|
* replay slots from a previously recorded file to operate the system,
|
|
possibly in multiple loops if the recorded sequence is convenient from the logical point of view.
|
|
|
|
The record-replay features are activated and configured using OAI configuration parameters
|
|
|
|
### Record mode
|
|
options for record mode are:
|
|
|
|
* `subframes-record` Activate record mode
|
|
* `subframes-file` Path of the file used for slots recording (default is `/tmp/iqfile`)
|
|
* `subframes-max` Maximum count of slots to be recorded in a file (default is 120000)
|
|
|
|
Note that the value of `--subframes-max` parameter needs to be tuned according to your RAM capabilities.
|
|
The default value is 120000, which allows for 120 seconds of record-replay but will require ~20GB of RAM and disk space.
|
|
If RAM does not allow for the parameter value, an error message will be displayed and the run will be aborted.
|
|
In record mode, to minimize performance impacts of operating software, slots are always saved into memory and
|
|
written to disk when the process terminates.
|
|
When you estimate the recorded sequence is achieved, you can terminate the nr-uesoftmodem by typing `CTRL-C`.
|
|
At that time, up to the value of `--subframes-max` slots will be written on disk.
|
|
The nr-uesoftmodem will indicate the exact count of slots written to disk, which may be less (but not higher)
|
|
than the value of `--subframes-max` parameter.
|
|
|
|
**Recording session example:**
|
|
|
|
```bash
|
|
./nr-uesoftmodem -O /home/oaitests/mediatek_sim.conf --numerology 1 -r 106 -C 3649440000 --band 78 -E --ue-fo-compensation --device.recplay.subframes-record 1 --device.recplay.subframes-file /home/iqs/oai-nrUE-17042023.dat --device.recplay.use-mmap 1 --device.recplay.subframes-max 30000
|
|
............................................
|
|
............................................
|
|
............................................
|
|
^C
|
|
[HW] Writing file header to /home/iqs/oai-nrUE-17042023.dat
|
|
[HW] Writing 4565 subframes to /home/iqs/oai-nrUE-17042023.dat
|
|
[HW] File /home/iqs/oai-nrUE-17042023.dat closed
|
|
[HW] releasing USRP
|
|
```
|
|
|
|
### Replay mode
|
|
Replaying I/Q works only for nr-uesoftmodem at 40MHz bandwidth 3/4 sampling.
|
|
Mismatch between file content and run time parameters might lead to unpredictable results.
|
|
options for replay mode are:
|
|
|
|
* `subframes-replay` Activate replay mode
|
|
* `subframes-file` Path of the file used for slots replay (default is `/tmp/iqfile`)
|
|
* `subframes-loops` Number of iterations to replay the entire slots file (default is 5)
|
|
* `use-mmap` Boolean, set to 1 (true) by default, iq file is map to memory if true, otherwise iq's are read from file.
|
|
|
|
**Replay mode session example:**
|
|
|
|
```bash
|
|
./nr-uesoftmodem -O /home/oaitests/mediatek_sim.conf --numerology 1 -r 106 -C 3649440000 --band 78 -E --ue-fo-compensation --device.recplay.subframes-replay 1 --device.recplay.subframes-file /home/iqs/oai-nrUE-17042023.dat --device.recplay.use-mmap 1 --device.recplay.subframes-loops 1
|
|
..................................
|
|
..................................
|
|
[HW] Replay iqs from USRP B200 device, bandwidth 4.000000e+07
|
|
[HW] Loaded 4565 subframes.
|
|
[HW] iqplayer device initialized, replay /home/iqs/oai-nrUE-17042023.dat for 1 iteration(s)
|
|
..................................
|
|
..................................
|
|
```
|