mirror of https://github.com/PentHertz/srsLTE.git
133 lines
4.2 KiB
Matlab
133 lines
4.2 KiB
Matlab
clear
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%% PHICH encoding/decoding
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%% Setup simulation
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Npackets = 80;
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SNR_values = linspace(-6,0,6);
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enable_fading=false;
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addpath('../../debug/srslte/lib/phch/test')
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%% Cell-Wide Settings
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enbConfig.NDLRB = 50; % No of Downlink RBs in total BW
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enbConfig.CyclicPrefix = 'Normal'; % CP length
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enbConfig.Ng = 'One'; % HICH groups
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enbConfig.CellRefP = 1; % 1-antenna ports
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enbConfig.NCellID = 36; % Physical layer cell identity
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enbConfig.NSubframe = 5; % Subframe number 0
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enbConfig.DuplexMode = 'FDD'; % Frame structure
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enbConfig.PHICHDuration = 'Normal';
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%% Define HI resource
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hi_res = [1 1];
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ack_bit = 1;
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%% Setup Fading channel model
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if (enable_fading)
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cfg.Seed = 8; % Random channel seed
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cfg.NRxAnts = 1; % 1 receive antenna
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cfg.DelayProfile = 'EPA'; % EVA delay spread
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cfg.DopplerFreq = 5; % 120Hz Doppler frequency
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cfg.MIMOCorrelation = 'Low'; % Low (no) MIMO correlation
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cfg.InitTime = 0; % Initialize at time zero
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cfg.NTerms = 16; % Oscillators used in fading model
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cfg.ModelType = 'GMEDS'; % Rayleigh fading model type
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cfg.InitPhase = 'Random'; % Random initial phases
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cfg.NormalizePathGains = 'On'; % Normalize delay profile power
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cfg.NormalizeTxAnts = 'On'; % Normalize for transmit antennas
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end
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% Setup channel equalizer
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cec.PilotAverage = 'UserDefined'; % Type of pilot averaging
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cec.FreqWindow = 9; % Frequency window size
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cec.TimeWindow = 9; % Time window size
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cec.InterpType = 'linear'; % 2D interpolation type
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cec.InterpWindow = 'Causal'; % Interpolation window type
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cec.InterpWinSize = 1; % Interpolation window size
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%% Generate TX subframe
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subframe_tx = lteDLResourceGrid(enbConfig);
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%% Genearte PHICH signal
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hi_sym_tx = ltePHICH(enbConfig, [hi_res ack_bit]);
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hi_indices = ltePHICHIndices(enbConfig);
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subframe_tx(hi_indices)=hi_sym_tx;
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%% Add references to subframe
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cellRsSym = lteCellRS(enbConfig);
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cellRsInd = lteCellRSIndices(enbConfig);
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subframe_tx(cellRsInd) = cellRsSym;
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%% Modulate signal
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[txWaveform, info] = lteOFDMModulate(enbConfig,subframe_tx);
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cfg.SamplingRate = info.SamplingRate;
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%% Start simulation
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decoded = zeros(size(SNR_values));
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decoded_srslte = zeros(size(SNR_values));
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for snr_idx=1:length(SNR_values)
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SNRdB = SNR_values(snr_idx);
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SNR = 10^(SNRdB/10); % Linear SNR
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N0 = 1/(sqrt(2.0*enbConfig.CellRefP*double(info.Nfft))*SNR);
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for i=1:Npackets
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%% Fading
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rxWaveform = sum(txWaveform,2);
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if (enable_fading)
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rxWaveform = lteFadingChannel(cfg,rxWaveform);
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end
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%% Noise Addition
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noise = N0*complex(randn(size(rxWaveform)), randn(size(rxWaveform)));
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rxWaveform = rxWaveform + noise;
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%% Demodulate
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subframe_rx = lteOFDMDemodulate(enbConfig, rxWaveform);
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%% Channel estimation
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if (enable_fading)
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[hest, nest] = lteDLChannelEstimate(enbConfig, cec, subframe_rx);
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else
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hest=ones(size(subframe_rx));
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nest=0;
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end
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%% Extract resources
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phichSymbolsRx = subframe_rx(hi_indices);
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phichSymbolsHest = hest(hi_indices);
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%% PHICH decoding
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[hi, hi_symbols] = ltePHICHDecode(enbConfig,hi_res, phichSymbolsRx, phichSymbolsHest, nest);
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decoded(snr_idx) = decoded(snr_idx) + (hi == ack_bit);
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%% Same with srsLTE
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[hi_srslte, hi_symbols_srslte] = srslte_phich(enbConfig, hi_res, subframe_rx, hest, nest);
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decoded_srslte(snr_idx) = decoded_srslte(snr_idx) + (hi_srslte == ack_bit);
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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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semilogy(SNR_values,1-decoded/Npackets,'bo-',...
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SNR_values,1-decoded_srslte/Npackets, 'ro-')
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grid on
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legend('Matlab','srsLTE')
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xlabel('SNR (dB)')
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ylabel('BLER')
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axis([min(SNR_values) max(SNR_values) 1/Npackets/10 1])
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else
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scatter(real(hi_symbols),imag(hi_symbols))
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hold on
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scatter(real(hi_symbols_srslte),imag(hi_symbols_srslte))
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hold off
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grid on;
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axis([-2 2 -2 2])
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disp(hi)
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disp(hi_srslte)
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end
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