Commit 74e53579 authored by Florian Kaltenberger's avatar Florian Kaltenberger
Browse files

new version doing MIMO channel estimates

git-svn-id: http://svn.eurecom.fr/openair4G/trunk@5242 818b1a75-f10b-46b9-bf7c-635c3b92a50f
parent a026c87b
close all
clear all
enable_plots=2; %eanbles figures
enable_plots=1; %eanbles figures
%% preload and init data
addpath('../../../openair1/PHY/LTE_REFSIG');
......@@ -16,49 +16,48 @@ frame_length = ofdm_symbol_length*num_symbols_frame;
useful_carriers = num_carriers-num_zeros-1;
%filename = 'E:\EMOS\corridor\lab tests\eNB_data_20140321_184441.EMOS';
filename = 'E:\EMOS\corridor\711MHz\eNB_data_20140324_113931.EMOS';
%filename = 'D:\trials1 day 1 771.5MHz\eNB_data_20140327_153151.EMOS';
destdir = 'E:\EMOS\corridor\trials1 day1\711.5MHz';
filename = 'D:\trials1 train extracted\eNB_data_20140331_UHF_run1.EMOS';
destdir = 'E:\EMOS\corridor\trials1 train';
samples_slot = 7680/2;
slots_per_frame = 20;
nframes = 100;
nant=3;
nant_rx=3;
nant_tx=4;
d = dir(filename);
nblocks = floor(d.bytes/(samples_slot*slots_per_frame*nframes*nant*4));
PDP_total = zeros(nblocks*nframes,useful_carriers/4);
nblocks = floor(d.bytes/(samples_slot*slots_per_frame*nframes*nant_rx*4));
PDP_total = zeros(nblocks*nframes,useful_carriers/4,nant_tx,nant_rx);
%% main loop
fid = fopen(filename,'r');
% advance 1 minute of measurements (the synchronization algorithm does not
% work so well for low SNR yet)
fseek(fid,samples_slot*slots_per_frame*nframes*nant_rx*60*2,'bof');
vStorage = []; %%
vStorage = [];
block = 1;
start=2;
while ~feof(fid)
fprintf(1,'Processing block %d of %d',block,nblocks);
[v,c]=fread(fid, samples_slot*slots_per_frame*nframes*nant*2, 'int16',0,'ieee-le');
[v,c]=fread(fid, samples_slot*slots_per_frame*nframes*nant_rx*2, 'int16',0,'ieee-le');
if (c==0)
break
end
v1 = double(v(1:2:end))+1j*double(v(2:2:end));
nframes = 100;
v2 = zeros(samples_slot*slots_per_frame*nframes,nant);
v2 = zeros(samples_slot*slots_per_frame*nframes,nant_rx);
for slot=1:slots_per_frame*nframes
for a=1:nant
for a=1:nant_rx
v2((slot-1)*samples_slot+1:slot*samples_slot,a) = ...
v1((slot-1)*samples_slot*nant+(a-1)*samples_slot+1:...
(slot-1)*samples_slot*nant+ a *samples_slot,1);
v1((slot-1)*samples_slot*nant_rx+(a-1)*samples_slot+1:...
(slot-1)*samples_slot*nant_rx+ a *samples_slot,1);
end
end
v2 = [vStorage; v2] ;%%
v2 = [vStorage; v2] ; %handle boundaries between blocks
if size(v2,1) > frame_length*nframes ;
nframes = floor(size(v2,1) / frame_length) ;
vStorage = v2(frame_length*nframes+1:end,:) ;
......@@ -71,8 +70,8 @@ while ~feof(fid)
plot(20*log10(abs(fftshift(fft(v2)))))
end
%% frame start detection
% if block==1
%% frame start detection
if block==1
[corr,lag] = xcorr(v2(:,1),pss_t);
%[m,idx]=max(abs(corr));
%[m,idx]=peaksfinder(corr,frame_length);
......@@ -80,7 +79,7 @@ while ~feof(fid)
tmp = corr(nframes*slots_per_frame*samples_slot:end);
tmp2 = reshape(tmp,slots_per_frame*samples_slot,nframes);
[m,idx] = max(abs(tmp2),[],1);
frame_offset = round(mean(idx)) - prefix_length;
frame_offset = round(mean(idx(1:10))) - prefix_length;
if enable_plots>=2
figure(2);
......@@ -89,32 +88,45 @@ while ~feof(fid)
hold on
plot(frame_offset,m(1),'ro')
end
% end
else
% after the first block we are synchronized
frame_offset = prefix_length/8;
end
%%
for i=start:nframes;
for i=1:nframes;
fprintf(1,'.');
frame_start = (slots_per_frame*samples_slot)*(i-1)+frame_offset+1;
%frame_start = lag(idx(i))-prefix_length;
% frame_start = lag(i) - prefix_length;
if i<nframes
%% ofdm receiver
received_f = OFDM_RX(v2(frame_start:frame_start+frame_length,:),num_carriers,useful_carriers,prefix_length,num_symbols_frame);
else
vStorage = [v2(frame_start:end,:) ; vStorage]; %%
vStorage = [v2(frame_start:end,:) ; vStorage]; % handle block boundaries
end
%% MIMO channel estimation
H = zeros(num_symbols_frame/2,useful_carriers/4,nant_tx,nant_rx);
for itx=1:nant_tx
% f_start and t_start indicate the start of the pilots in time
% and frequency according to the specifications (see .doc file).
% t_start has to be >=2, since the first symbol is the PSS.
f_start = mod(itx-1,2)*2+1;
t_start = floor((itx-1)/2)+1;
for irx=1:nant_rx
H(:,:,itx,irx)=conj(squeeze(f3(itx,t_start:2:end,f_start:4:end))).*received_f(t_start:2:end,f_start:4:end,irx);
end
end
%% channel estimation
H=conj(squeeze(f3(1,3:2:end,1:4:end))).*received_f(3:2:end,1:4:end,1);
Ht = ifft(H,[],2);
PDP = mean(abs(Ht).^2,1);
PDP_total((block-1)*nframes+i+1,:) = PDP;
PDP_all = squeeze(mean(mean(PDP,3),4));
PDP_total((block-1)*nframes+i+1,:,:,:) = PDP;
[m,idx] = max(fft(ifft(PDP),num_carriers));
% adjust frame offset base on channel estimate to compensate for
% timing drift. We try to keep the peak of the impulse response at
% sample prefix_length/8.
[m,idx] = max(fft(ifft(PDP_all),num_carriers));
offset = idx - prefix_length/8;
if offset > prefix_length
offset = offset - num_carriers;
......@@ -125,15 +137,28 @@ while ~feof(fid)
if enable_plots>=1
figure(3)
surf(20*log10(abs(Ht)))
xlabel('delay time [samples]')
ylabel('time [OFDM symbol]')
zlabel('power [dB]')
shading interp
for itx=1:nant_tx
for irx=1:nant_rx
subplot(nant_tx,nant_rx,(itx-1)*nant_rx + irx);
surf(20*log10(abs(Ht(:,:,itx,irx))))
%xlabel('time [OFDM symbol]')
%ylabel('delay time [samples]')
%zlabel('power [dB]')
shading interp
end
end
figure(4)
plot(10*log10(PDP))
xlabel('delay time [samples]')
ylabel('power [dB]')
for itx=1:nant_tx
for irx=1:nant_rx
subplot(nant_tx,nant_rx,(itx-1)*nant_rx + irx);
plot(10*log10(PDP(:,:,itx,irx)))
ylim([50 80])
xlim([0 75])
%xlabel('delay time [samples]')
%ylabel('power [dB]')
end
end
drawnow
end
end
......
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