adding script to generate and read 30MHz EMOS records

git-svn-id: http://svn.eurecom.fr/openair4G/trunk@5145 818b1a75-f10b-46b9-bf7c-635c3b92a50f

targets/PROJECTS/CORRIDOR/emos_read_ca.m

@@ -0,0 +1,77 @@
+close all
+clear all
+nant1 = 1;
+nant2 = 2;
+samples_slot1 = 7680*2;
+samples_slot2 = 7680;
+samples_slot_agg = nant1*samples_slot1 + nant2*samples_slot2;
+nframes = 10;
+slots_per_frame = 20;
+
+%% read data
+fid = fopen('E:\EMOS\corridor\eNB_data_20140311_173205.EMOS','r');
+[v,c]=fread(fid, 2*samples_slot_agg*slots_per_frame*nframes, 'int16',0,'ieee-le'); 
+fclose(fid);
+v0 = double(v(1:2:end,:))+1j*double(v(2:2:end,:));
+
+%%
+v1 = zeros(samples_slot1*slots_per_frame*nframes,nant1);
+v2 = zeros(samples_slot1*slots_per_frame*nframes,nant2);
+for slot=1:slots_per_frame*nframes
+    v1((slot-1)*samples_slot1+1:slot*samples_slot1,1) = v0((slot-1)*samples_slot_agg+1:slot*samples_slot_agg-samples_slot2*nant2,1);
+    v2((slot-1)*samples_slot2+1:slot*samples_slot2,1) = v0((slot-1)*samples_slot_agg+samples_slot1+1:slot*samples_slot_agg-samples_slot2,1);
+    v2((slot-1)*samples_slot2+1:slot*samples_slot2,2) = v0((slot-1)*samples_slot_agg+samples_slot1+samples_slot2+1:slot*samples_slot_agg,1);
+end
+
+%%
+figure(1)
+plot(20*log10(abs(fftshift(fft(v1)))))
+figure(2)
+plot(20*log10(abs(fftshift(fft(v2)))))
+
+
+%% sync
+addpath('../../../openair1/PHY/LTE_REFSIG');
+primary_synch; %loads the primary sync signal
+
+pss_t = upsample(primary_synch0_time,4*2);
+[corr,lag] = xcorr(v2(:,1),pss_t);
+figure(3);
+plot(lag,abs(corr));
+
+%% frame start detection
+load('E:\EMOS\corridor\ofdm_pilots_sync_30MHz.mat');
+ofdm_symbol_length = num_carriers + prefix_length;
+frame_length = ofdm_symbol_length*num_symbols_frame;
+useful_carriers = num_carriers-num_zeros-1;
+
+% TODO: do a proper peak detection. for now just take the max
+[m,i]=max(abs(corr));
+frame_start = lag(i) - prefix_length;
+
+%% ofdm receiver
+received = v2(frame_start:frame_start+frame_length,1);
+received_f = zeros(num_symbols_frame,useful_carriers);
+for i=0:num_symbols_frame-1;
+    ifblock=received(i*ofdm_symbol_length+[1:ofdm_symbol_length]);
+    ifblock(1:prefix_length)=[];
+    fblock=fft(ifblock);
+    received_f(i+1,:) = [fblock(2:useful_carriers/2+1); fblock(end-useful_carriers/2+1:end)];
+end
+
+%% channel estimation
+H=conj(f2).*received_f;
+Ht = ifft(H,[],2);
+PDP = mean(abs(Ht(2:end,:).^2),1);
+figure(3)
+surf(20*log10(abs(Ht)))
+xlabel('time [OFDM symbol]')
+ylabel('delay time [samples]')
+zlabel('power [dB]')
+shading interp
+figure(4)
+plot(10*log10(PDP))
+xlabel('delay time [samples]')
+ylabel('power [dB]')
+
+

targets/PROJECTS/CORRIDOR/generation_ca.m

@@ -3,6 +3,8 @@
 %addpath('../../../openair1/PHY/LTE_REFSIG/')
 %addpath('../../../targets/ARCH/EXMIMO/USERSPACE/OCTAVE')
 
+rng(42); %make sure seed random numbers are alwyas the same
+
 % load the LTE sync sequence
 primary_synch;
 
@@ -44,8 +46,8 @@ pss0_up_cp = [pss0_up(num_carriers-prefix_length+1:end) pss0_up];
 s2(1:num_carriers+prefix_length) = pss0_up_cp;
 
 %% combine the two carriers
-f1_shift = -7.5e6;
+f1_shift = -5e6;
-f2_shift = 7.5e6;
+f2_shift = 10e6;
 sample_rate = 30.72e6*2;
 s1_up = interp(s1,2);
 s1_shift = s1_up .* exp(2*1i*pi*f1_shift*(0:length(s1_up)-1)/sample_rate);
@@ -53,8 +55,11 @@ s2_up = interp(s2,4);
 s2_shift = s2_up .* exp(2*1i*pi*f2_shift*(0:length(s2_up)-1)/sample_rate);
 s = s1_shift + s2_shift/sqrt(2);
 
-plot(abs(fftshift(fft(s))))
+%%
+figure(1)
+hold off
+plot(linspace(-sample_rate/2,sample_rate/2,length(s)),20*log10(abs(fftshift(fft(s)))))
 
 %% save for later use (channel estimation and transmission with the SMBV)
-save('ofdm_pilots_sync_30MHz.mat','-v7','s','f','num_carriers','num_zeros','prefix_length','num_symbols_frame','preamble_length');
+save('ofdm_pilots_sync_30MHz.mat','-v7','s','f1','f2','num_carriers','num_zeros','prefix_length','num_symbols_frame','preamble_length');
-mat2wv(s1, 'ofdm_pilots_sync_30MHz.wv', sample_rate, 1);
+mat2wv(s, 'ofdm_pilots_sync_30MHz.wv', sample_rate, 1);