How to simulate System Level Simulator to get BLER curve with MIESM for MU-MIMO

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  • #8391
    Roesdiade
    Participant

    Hi all,

    I am newbie to use LTE system level simulator.
    I have read the documentation but confuse how to begin and custom parameters that I need.
    1. Would anyone like to tell me how to plot BLER curve with MIESM based Effective SINR, MCS, CQI and adjustment factor Beta?
    is it possible using system level or I have to use DL link system simulator?

    I do not find which file that consist formula from my reference, such as SINR vector consisted of symbol information from MI I (Y ; X1|(|h_1^⋆ p_1 | ,|h_1^⋆ p_2 |))
    2. where the process of RBI, RBIRabs, RBIR to get Effective SINR?

    In references, there is adjustment factor Beta that should be compared with AWGN curve to obtain BLER.
    3. in LTE_load_params_dependant.m file, the Beta is given vector value, what reference used for the value?

    references: Imran Latif, Link Abstraction for Multi-User MIMO in LTE using Interference-Aware Receiver

    Thank you very much for your help.

    #8396

    Hi Roesdiade,

    Welcome in our forum of Vienna LTE-A System Level SImulator!

    For any type of simulation scenario, by setting LTE_config.show_network = true; you will automatically get two plots: first the LTE BLER for CQIs 1-15 and second, the SNR-CQI mapping done for 10% BLER. These reslts come after calibration of our system level simulator with link level simulator. Also the parameter beta used for MIESM is calibrated for each CQI.

    Regarding the MIESM algorithm used in our simulator, you can reffer to the following paper:
    L. Wan, S. Tsai, and M. Almgren, “A fading-insensitive performance metric for a unified link quality model,” in Proc. IEEE Wireless Communications
    and Networking Conference (WCNC2006), vol. 4, Apr. 2006, pp. 2110–2114;

    As our algorithm doesn’t follow the paper you reffer to, accordingly parameters such RBi, RBIR etc do not exist. Intead you could check the file in +utils/miesmAveragerFast.m for details.

    Please let me know if you have any further question!

    Best regards,
    Fjolla

    #8445
    Roesdiade
    Participant

    Hi many thanks Fjolla,

    I have some more questions.

    For any type of simulation scenario, by setting LTE_config.show_network = true; you will automatically get two plots: first the LTE BLER for CQIs 1-15 and second, the SNR-CQI mapping done for 10% BLER. These reslts come after calibration of our system level simulator with link level simulator. Also the parameter beta used for MIESM is calibrated for each CQI.

    I have found in LTE_load_params_dependant.m that called in LTE_sim_main.m, there are .mat given values from link level simulator.
    So, the system level is processing output of link level simulator, right? and I have to do iterate link level to get different .mat values result?

    My reference

    I. Latif, F. Kaltenberger and R. Knopp, “Link abstraction for multi-user MIMO in LTE using interference-aware receiver,” 2012 IEEE Wireless Communications and Networking Conference (WCNC), Shanghai, 2012, pp. 842-846.

    that also refer to this reference

    Regarding the MIESM algorithm used in our simulator, you can reffer to the following paper:
    L. Wan, S. Tsai, and M. Almgren, “A fading-insensitive performance metric for a unified link quality model,” in Proc. IEEE Wireless Communications
    and Networking Conference (WCNC2006), vol. 4, Apr. 2006, pp. 2110–2114;

    said that we can simplify calculation of link level with system level by MIESM method that mapping Symbol Information per subcarrier to obtain SINR effective and plot the BLER abstraction.

    in +utils/miesmAveragerFast.m to get BICM or MI based for quality model, it is clear how to get SINR effective, but I do not know to realize the BLERabstraction curve to SNR based MCS as result in Lei Wan paper. would you like to show me how to plot it?

    Is it possible if I have beta table from previous work, replaces beta calculation +utils/miesmAveragerFast.m in order to get better time processing?

    Thank you for your help.

    #8595
    Roesdiade
    Participant

    Hi all,
    How to plot like this figure from DL System Level Simulator? I’ve trace that plotted BLER is loaded from link level AWGN SISO in data_files/AWGN_BLERs folder. MU-MIMO abstraction (MI-based) for LTE MCS 9 and 16
    thank you very much.

    #8600
    Roesdiade
    Participant
    #8611

    Dear Roesdiade,

    A few words about the physical layer abstraction that happens in the so-called link performance model in our system level simulator:
    1) First, from the subcarrier post-equalization SINR, an effective SINR is evaluated based on the MIESM (Mutual Information Effective SINR Mapping). While theoretically possible, it is in practice unfeasibly complex to obtain a mapping table of all possible combinations of the subcarrier SINR values to a BLER value for each MCS (Modualtion and Coding Scheme).

    2) Second, The effective SINR is then mapped by means of an AWGN BLER curve of the corresponding MCS to a BLER value. The AWGN BLER curves are obtained form link level simulations. This would represent the solid line in the example you showed above. To plot this you can use the script LTE_init_load_BLER_curves.m, where the AWGN BLER curves are loaded.

    For each user, the effective SINR value is saved in the results file at simulation_traces.UE_traces as TB_SINR_dB, and the BLER value in the parameter BLER. If you want to plot it for specific MCSs, then you have to filter the results for the users that reported a specific TB_CQI.

    Best regards,
    Fjolla

    #8620
    Roesdiade
    Participant

    Thank you Fjolla,

    I am Sorry for another question because of my ignorance,

    –to plot BLER specific MCS–
    I do not have idea to plot the BLER per MCS.
    I have check in folder results and load to workspace, I run the system for 10 TTI, 19 eNodeB and 3 UE/sektor
    in the_UE_traces, I got these parameters value, but without parameter consisted BLER word.
    the_UE_traces(1,1).SINR different > for 10 column 1×66 double 1×66 double
    the_UE_traces(1,1).SNR_dB > same for 10 column 16.47289936 64.65095473
    the_UE_traces(1,1).wideband_SINR > same for 10 column -8.817516518 8.736185062
    the_UE_traces(1,1).mean_wideband_SINR > only 1 column -8.817516518 8.736185062
    the_UE_traces(1,1).TB_SINR_dB > different for 10 column -5.784585418 7.47681086
    the_UE_traces(1,1).TB_CQI > different for 10 column 2 12
    the_UE_traces(1,1).TB_size > different for 10 column 736 1152

    in the_eNodeB_traces, I got average_BLER with blank value.

    please guide me how to plot BLER per MCS to SINR or SNR (dB). thank you very much..

    #8624

    Dear Roesdiade,

    Our simulator has a feature to compress or not the results file, depending on which parameters do you want to save. In your case, in the main launcher file, you have to set LTE_config.compact_results_file = false -> no compression, meaning that it will also save the BLER values. If you set LTE_config.compact_results_file = 1, less parameters will be saved. For more detials on that you can check the file LTE_sim_main.m and modify it depending on which parameters do you want to save.

    Best regards,
    Fjolla

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