mirror of https://github.com/PentHertz/srsLTE.git
106 lines
3.7 KiB
Matlab
106 lines
3.7 KiB
Matlab
%% PDCCH Blind Search and DCI Decoding
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%% Cell-Wide Settings
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% A structure |enbConfig| is used to configure the eNodeB.
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Npackets = 50;
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SNR_values =linspace(-5,3,8);
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enbConfig.NDLRB = 15; % No of Downlink RBs in total BW
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enbConfig.CyclicPrefix = 'Normal'; % CP length
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enbConfig.CFI = 3; ; % 4 PDCCH symbols as NDLRB <= 10
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enbConfig.Ng = 'Sixth'; % HICH groups
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enbConfig.CellRefP = 2; % 1-antenna ports
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enbConfig.NCellID = 10; % Physical layer cell identity
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enbConfig.NSubframe = 0; % Subframe number 0
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enbConfig.DuplexMode = 'FDD'; % Frame structure
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enbConfig.PHICHDuration = 'Normal';
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%% DCI Message Generation
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% Generate a DCI message to be mapped to the PDCCH.
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dciConfig.DCIFormat = 'Format1A'; % DCI message format
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dciConfig.Allocation.RIV = 26; % Resource indication value
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% Create DCI message for given configuration
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[dciMessage, dciMessageBits] = lteDCI(enbConfig, dciConfig);
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%% DCI Channel Coding
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C_RNTI = 65535; % 16-bit UE-specific mask
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pdcchConfig.RNTI = C_RNTI; % Radio network temporary identifier
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pdcchConfig.PDCCHFormat = 3; % PDCCH format
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% DCI message bits coding to form coded DCI bits
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codedDciBits = lteDCIEncode(pdcchConfig, dciMessageBits);
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%% PDCCH Bits Generation
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pdcchDims = ltePDCCHInfo(enbConfig);
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% Initialize elements with -1 to indicate that all the bits are unused
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pdcchBits = -1*ones(pdcchDims.MTot, 1);
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% Perform search space for UE-specific control channel candidates.
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candidates = ltePDCCHSpace(enbConfig, pdcchConfig, {'bits', '1based'});
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Ncad=randi(length(candidates),1,1);
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% Map PDCCH payload on available UE-specific candidate. In this example the
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% first available candidate is used to map the coded DCI bits.
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pdcchBits ( candidates(Ncad, 1) : candidates(Ncad, 2) ) = codedDciBits;
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%% PDCCH Complex-Valued Modulated Symbol Generation
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pdcchSymbols = ltePDCCH(enbConfig, pdcchBits);
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pdcchIndices = ltePDCCHIndices(enbConfig,{'1based'});
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decoded = zeros(size(SNR_values));
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decoded_liblte = zeros(size(SNR_values));
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Nports = enbConfig.CellRefP;
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ueConfig.RNTI = C_RNTI;
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subframe_tx = lteDLResourceGrid(enbConfig);
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subframe_tx(pdcchIndices) = pdcchSymbols;
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addpath('../../debug/lte/phy/lib/phch/test')
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parfor snr_idx=1:length(SNR_values)
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SNRdB = SNR_values(snr_idx);
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for i=1:Npackets
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%% Noise Addition
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SNR = 10^(SNRdB/10); % Linear SNR
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N0 = 1/(sqrt(2.0*Nports)*SNR);
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noise = N0*complex(randn(size(subframe_tx)), randn(size(subframe_tx))); % Generate noise
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subframe_rx = sum(subframe_tx + noise,3); % Add noise to PDCCH symbols
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pdcchSymbolsNoisy = subframe_rx(pdcchIndices(:,1));
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%% PDCCH Decoding
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recPdcchBits = ltePDCCHDecode(enbConfig, pdcchSymbolsNoisy);
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%% Blind Decoding using DCI Search
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[rxDCI, rxDCIBits] = ltePDCCHSearch(enbConfig, ueConfig, recPdcchBits);
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decoded(snr_idx) = decoded(snr_idx) + length(rxDCI);
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[found_liblte, llr, viterbi_in] = liblte_pdcch(enbConfig, ueConfig.RNTI, subframe_rx);
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decoded_liblte(snr_idx) = decoded_liblte(snr_idx)+found_liblte;
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end
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fprintf('SNR: %.1f\n',SNRdB)
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end
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if (Npackets>1)
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plot(SNR_values,1-decoded/Npackets,SNR_values,1-decoded_liblte/Npackets)
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grid on
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legend('Matlab','libLTE')
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else
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disp(decoded_liblte)
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end
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