59 lines
1.5 KiB
Matlab
59 lines
1.5 KiB
Matlab
close all
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clear all
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%% read data
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fid = fopen('E:\EMOS\corridor\eNB_data_20140108_185919.EMOS','r');
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[v,c]=fread(fid, 76800*4*100, 'int16',0,'ieee-le');
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v2 = double(v(1:2:end))+1j*double(v(2:2:end));
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fclose(fid);
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figure(1)
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plot(abs(fftshift(fft(v2))))
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%% sync
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addpath('../../../openair1/PHY/LTE_REFSIG');
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primary_synch; %loads the primary sync signal
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pss_t = upsample(primary_synch0_time,4*4);
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[corr,lag] = xcorr(v2,pss_t);
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figure(2);
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plot(lag,abs(corr));
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%% frame start detection
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%load('../LOCALIZATION/ofdm_pilots_sync_2048.mat');
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load('E:\EMOS\corridor\ofdm_pilots_sync_2048_v7.mat');
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ofdm_symbol_length = num_carriers + prefix_length;
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frame_length = ofdm_symbol_length*num_symbols_frame;
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useful_carriers = num_carriers-num_zeros-1;
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% TODO: do a proper peak detection. for now just take the max
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[m,i]=max(abs(corr));
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frame_start = lag(i) - prefix_length;
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%% ofdm receiver
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received = v2(frame_start:frame_start+frame_length);
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received_f = zeros(num_symbols_frame,useful_carriers);
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for i=0:num_symbols_frame-1;
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ifblock=received(i*ofdm_symbol_length+[1:ofdm_symbol_length]);
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ifblock(1:prefix_length)=[];
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fblock=fft(ifblock);
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received_f(i+1,:) = [fblock(2:useful_carriers/2+1); fblock(end-useful_carriers/2+1:end)];
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end
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%% channel estimation
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H=conj(f).*received_f;
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Ht = ifft(H,[],2);
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PDP = mean(abs(Ht(2:end,:).^2),1);
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figure(3)
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surf(20*log10(abs(Ht)))
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xlabel('time [OFDM symbol]')
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ylabel('delay time [samples]')
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zlabel('power [dB]')
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shading interp
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figure(4)
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plot(10*log10(PDP))
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xlabel('delay time [samples]')
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ylabel('power [dB]')
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