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+## 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](../../../../targets/ARCH/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)