## configuring the channel simulation Oai channel simulation is using the [config module](../../../config/config.md) to get its parameters at init time. The [telnet server](../../telnetsrv/DOC/telnetsrv.md) includes a set of commands which can be used to dynamically modify some channel model parameters All channel simulation parameters are defined in the `channelmod` section. Most parameters are specific to a channel model and are only used by the rfsimulator. ### global parameters | name | type | default | description | |:---:|:---:|:---:|:----| | `max_chan` | integer | `25` | Maximum number of channel model that can be defined in the system. Must be greater than the number of model definitions in the model list loaded at init time. | | `modellist` | character string | `DefaultChannelList` | Name of the channel models list to load at init time. | ### Model lists Several model lists can be defined in the oai configuration file. One, defined by the `modellist` parameter is loaded at init time. In the configuration file each model list item describes a channel model using a group of parameters: | parameter name | type | default | description | |:---:|:---:|:---:|:----| | `model name` | character string | mandatory |name of the model, as used in the code to retrieve a model definition| | `type` | | `AWGN` | name of the channel modelization algorithm applied on rf signal. The list of available model types can be listed via the [telnet server](../../telnetsrv/DOC/telnetsrv.md) or by entering an invalid type name | | `ploss_dB` | real (float) | | path loss of the channel, in dB | | `noise_power_dB` | real (double) | | noise of the channel in dB | | `forgetfact` | real (double) | | | | `offset` | integer | | | | `ds_tdl` | real double | | | Channel simulation parameters can also be specified on the command line: ```bash ./lte-softmodem -O ../../../ci-scripts/conf_files/enb.band7.tm1.50prb.usrpb210.conf --noS1 --rfsim --rfsimulator.options chanmod --rfsimulator.serveraddr enb --telnetsrv --channelmod.modellist modellist_rfsimu_2 --channelmod.modellist_rfsimu_2.[1].offset 120 ``` ### Using the telnet server to modify channel simulator parameters The telnet server includes a `channelmod` command which can be used to dynamically modify some channel model parameters. This command is only available when channel simulation is enabled (via `rfsimulator.options chanmod` option when running the rfsimulator. `channelmod` command has its own help: ``` $ telnet 127.0.0.1 9090 Trying 127.0.0.1... Connected to 127.0.0.1. Escape character is '^]'. softmodem_enb> help ..................................... module 6 = channelmod: channelmod help channelmod show <predef,current> channelmod modify <channelid> <param> <value> module 7 = rfsimu: rfsimu setmodel <model name> <model type> softmodem_enb> channelmod help channelmod commands can be used to display or modify channel models parameters channelmod show predef: display predefined model algorithms available in oai channelmod show current: display the currently used models in the running executable channelmod modify <model index> <param name> <param value>: set the specified parameters in a current model to the given value <model index> specifies the model, the show current model command can be used to list the current models indexes <param name> can be one of "riceanf", "aoa", "randaoa", "ploss", "noise_power_dB", "offset", "forgetf" softmodem_enb> ``` The [rfsimulator documentation](../../../../radio/rfsimulator/README.md ) has also some specific information when using the channel simulation via this tool. [channel simulation main page](channel_simulation.md) [oai Wikis home](https://gitlab.eurecom.fr/oai/openairinterface5g/wikis/home)