added George's peak finder to emos_read.m
git-svn-id: http://svn.eurecom.fr/openair4G/trunk@5179 818b1a75-f10b-46b9-bf7c-635c3b92a50f
This commit is contained in:
Florian Kaltenberger
@@ -0,0 +1,13 @@
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function La = LanczosKernel(a,x0,samples)
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min = floor(x0) - a;
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max = ceil(x0) + a;
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min(min<1)=1;
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max(max>size(samples,2))=size(samples,2);
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La=zeros(size(x0,2),1);
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for i=1:size(x0,2)
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La(i)=sinc((-x0(i)+(min(i):max(i)))).*sinc(((-x0(i)+(min(i):max(i)))/a))*samples(min(i):max(i))';
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end
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@@ -1,58 +1,88 @@
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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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enable_plots=1; %eanbles figures
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figure(1)
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plot(abs(fftshift(fft(v2))))
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%% sync
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%% preload and init data
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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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filename = 'E:\EMOS\corridor\eNB_data_20140108_185919.EMOS';
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samples_slot = 7680*2;
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slots_per_frame = 20;
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nframes = 100;
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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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d = dir(filename);
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nblocks = floor(d.bytes/(samples_slot*slots_per_frame*nframes*4));
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PDP_total = zeros(nblocks*nframes,useful_carriers);
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%% main loop
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fid = fopen(filename,'r');
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block = 1;
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while ~feof(fid)
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fprintf(1,'Processing block %d of %d',block,nblocks);
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[v,c]=fread(fid, samples_slot*slots_per_frame*nframes*2, 'int16',0,'ieee-le');
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v2 = double(v(1:2:end))+1j*double(v(2:2:end));
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[corr,lag] = xcorr(v2,pss_t);
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if enable_plots>=2
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figure(1)
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plot(abs(fftshift(fft(v2))))
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figure(2);
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plot(lag,abs(corr));
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end
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%% frame start detection
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%[m,i]=max(abs(corr));
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[m,idx]=peaksfinder(corr,frame_length);
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for i=1:size(idx,2)-1; % the last frame is not complite
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fprintf(1,'.');
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frame_start = lag(idx(i))-prefix_length;
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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 j=0:num_symbols_frame-1;
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ifblock=received(j*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(j+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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PDP_total((block-1)*nframes+i+1,:) = PDP;
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if enable_plots>=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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end
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end
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fprintf(1,'\n');
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block = block+1;
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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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fclose(fid);
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@@ -0,0 +1,40 @@
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function [m,ind]=peaksfinder(corr,frame_length)
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threshold=45000;
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consecutivePos=[];
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highCorrVal=find(abs(corr)>threshold);
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num_peak=0;
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k=1;
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consecutivePos(1)=highCorrVal(1);
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for i_high=1:size(highCorrVal,1)-1
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if highCorrVal(i_high+1)-highCorrVal(i_high)==1
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consecutivePos(k+1)=highCorrVal(i_high+1);
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k=k+1;
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else
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num_peak=num_peak+1;
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[m(num_peak),temp_idx]=max(abs(corr(min(consecutivePos):max(consecutivePos))));
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ind(num_peak)=min(consecutivePos)-1+temp_idx;
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consecutivePos=[];
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consecutivePos(1)=highCorrVal(i_high+1);
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k=1;
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end
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end
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num_peak=num_peak+1;
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[m(num_peak),temp_idx]=max(abs(corr(min(consecutivePos):max(consecutivePos))));
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ind(num_peak)=min(consecutivePos)-1+temp_idx;
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% a bigining for make code which clculate the best peak in respect to whole frlames
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% corrMatrix=vec2mat(corr, frame_length);
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% corrMatrix(end,:)=[];
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% sumCorrMatrix=sum(abs(corrMatrix));
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% [Value Pos]=max(sumCorrMatrix);
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