Accessing Modulated Transmisson Symbols on Resource Element of every UE

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  • #11082
    ahmetemir
    Participant

    Hello,

    I‘m using Vienna LTE_Link_Level_1.7_r1089 simulator. I wonder how could I access transmisson modulated symbols on every resource element of one UE. For my purpose, I viewed LTE_TX.m I understood that this code calculate TX symbols on every subframe.

    There at Line 226 I saw code like these:

    tx_user_symbols = LTE_params.SymbolAlphabet{BS_output.UE_signaling(uu).MCS_and_scheduling.CQI_params(cw).modulation_order}(nibble+1).';

    and at Line 322

    tx_symbols{nn}(repmat(reshape(UE_mapping,[1 size(UE_mapping)]),[LTE_params.Nsc*LTE_params.Ns - ...
    sum(sum(NoData_indices(1:LTE_params.Nsc,1:LTE_params.Ns))),1,1])) = precode_y(nn,:);

    What is the difference of these codes? I couldn’t understand. How could I change this codes in order to calculate modulated symbols of every UEs on the system at every Resource Element.

    Best Wishes…

    • This topic was modified 2 years, 10 months ago by ahmetemir.
    • This topic was modified 2 years, 10 months ago by ahmetemir.
    #11089
    Stefan Schwarz
    Participant

    Hi,

    “precode_y” represent the symbols of a user after MIMO precoding. These symbols are obtained by multiplying “layer_x” with the precoding matrix. “layer_x” again is obtained from “tx_user_symbols” via layer mapping, and “tx_user_symbols” are the QAM modulated user symbols.

    “tx_symbols” contains the data of all scheduled users.

    None of these variables are however associated to resource elements. The actual mapping onto resource elements happens in “y_tx_assembled”.

    Best,
    Stefan.

    #11090
    ahmetemir
    Participant

    Hi Stefan,

    Thanks for your explanation. Doees tx_symbols contains the data of all scheduled users on Resource Block or a subframe?

    In fact, I want to design Non Orthogonal Multiple Access (NOMA) tranceiver on Link Level Simulator. I want to design transmitter composed of two user in a cell with controlled by simple eNodeB. At transmitte side at each time slot, two user will share the whole wideband for their transmission signlas and the modulated symbols intended for near and far user will be superposed. At the receiver side at each time- frequency resource element, I will use the SIC (Successive Interference Cancellation) receiver to detect the desired signal of near user.

    First of all , in order to design NOMA, at LTE_TX.m , I couldn’t see total system power. Where is the definiton or call function of power? Because of I have to use power split factors for near and far user inside superposed transmit signal ( transmit_signal= symbol_far_user* power_split_far*total power +symbol_near_user* power_split_near*total power ) Could I obtain symbol_far_user and symbol_near_user from tx_symbols at LTE_TX.m. At LTE_TX.m after Line 336 , Should I write the formula of superposed transmit signal formula??

    Would you give me advices please??

    Best Wishes

    • This reply was modified 2 years, 10 months ago by ahmetemir.
    • This reply was modified 2 years, 10 months ago by ahmetemir.
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