| Applicable versions | NetSim Standard | NetSim Pro |
| Applicable Releases | v14 |
The first step would be to create a 5G scenario. Let us take a scenario with 1 gNB and 1 UE with the following properties
gNB - UE distance = 1800m
Band = n78, C band. BW = 10 MHz
Pathloss Model: 3GPP Urban macro
The application flow is configured such that we have "full buffer" DL traffic at the gNB
then enable fading to model a time-varying channel; set the BLER target in the gNB properties as shown below.
In NetSim, the 5G Code Block Log file provides details such as the HARQ process ID, Transport Block Size (TBS), Modulation, Code Rate, CBS size, BLER value, CBG ID, CBG status, etc in a CSV file with time stamps and related gNB ID, UE ID, etc.
Enable Code Block logging, by going to the Configure Reports -> Logs option and enabling the LTENR Code Block Log checkbox as shown below.
After simulation completion, the LTENR_CodeBlock_Log.csv file can be accessed from the Simulation Results window under the Log files drop-down as shown.
To generate a plot of BLER vs Time from the Code Block log file, follow the steps explained below.
NetSim tracks the i-BLER or the init BLER, which is calculated on first transmissions only. The outer loop link adaptation algorithm in NetSim uses HARQ ACK/NACKs - from first transmissions when the NDI flag is true - to step up/down the fed-back SINR by a delta up/down. See section 3.9.27 of https://www.tetcos.com/downloads/v14/5G-NR.pdf for an explanation of how OLLA works in NetSim.
Please refer to the below link on how to import Plotting_BLER_vsTime.bas to the Code Block log Excel file to get the required plot.
How to import .bas file in MS-Excel?
A table and plot for init BLER vs Time will be created. Shown below are plots for BLER target = 0.1 and BLER target = 0.2
Fig: OLLA algorithm makes necessary adjustments to maintain the average init BLER equal to the BLER target. Target BLER = 0.1 in the top plot, and Target BLER = 0.2 in the bottom plot.
The experiment file associated with the example considered above for generating plots is attached. Users can download, import, and run simulations to understand the procedure.
Useful links
1. NetSim 5G overview: https://www.tetcos.com/5g.html
2. NetSim 5G (v14) detailed documentation: https://tetcos.com/netsim-documentation.html - 5G NR manual
3. NetSim 5G OLLA-BLER implementation: see section 3.9.27 of https://tetcos.com/downloads/v14.2/5G-NR.pdf
| Applicable Releases | v13.3 |
The first step would be to create a 5G scenario. Let us take a scenario with 1 gNB and 1 UE with the following properties
gNB - UE distance = 1800m
Band = n78, C band. BW = 10 MHz
Pathloss Model: 3GPP Urban macro
The application flow is configured such that we have "full buffer" DL traffic at the gNB
then enable fading to model a time-varying channel; set the BLER target in the gNB properties as shown below.
In NetSim, the 5G Code Block Log file provides details such as the HARQ process ID, Transport Block Size (TBS), Modulation, Code Rate, CBS size, BLER value, CBG ID, CBG status, etc in a CSV file with time stamps and related gNB ID, UE ID, etc.
Enable Code Block logging, by going to the Logs option and enabling the LTENR Code Block Log checkbox as shown below.
After simulation completion, the LTENR_CodeBlock_Log.csv file can be accessed from the Simulation Results window under the Log files drop-down as shown.
To generate a plot of BLER vs Time from the Code Block log file, follow the steps explained below.
NetSim tracks the i-BLER or the init BLER, which is calculated on first transmissions only. The outer loop link adaptation algorithm in NetSim uses HARQ ACK/NACKs - from first transmissions when the NDI flag is true - to step up/down the fed-back SINR by a delta up/down. See https://www.tetcos.com/help/v13.3/Technology-Libraries/5G-NR.html#outer_loop_link_adaptation_olla for an explanation of how OLLA works in NetSim.
Please refer to the below link on how to import Plotting_BLER_vsTime.bas to the Code Block log Excel file to get the required plot.
How to import .bas file in MS-Excel?
A table and plot for init BLER vs Time will be created. Shown below are plots for BLER target = 0.1 and BLER target = 0.2
Fig: OLLA algorithm makes necessary adjustments to maintain the average init BLER equal to the BLER target. Target BLER = 0.1 in the top plot, and Target BLER = 0.2 in the bottom plot.
The experiment file associated with the example considered above for generating plots is attached. Users can download, import, and run simulations to understand the procedure.
Useful links
1. NetSim 5G overview: https://www.tetcos.com/5g.html
2. NetSim 5G (v13.3) detailed documentation: https://www.tetcos.com/help/v13.3/Technology-Libraries/5G-NR.html
3. NetSim 5G OLLA-BLER implementation: https://www.tetcos.com/help/v13.3/Technology-Libraries/5G-NR.html#outer_loop_link_adaptation_olla