Commit 842258c6 authored by Florian Kaltenberger's avatar Florian Kaltenberger

adding script to generate and read 30MHz EMOS records

git-svn-id: http://svn.eurecom.fr/openair4G/trunk@5145 818b1a75-f10b-46b9-bf7c-635c3b92a50f
parent 1573f518
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]')
......@@ -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;
f2_shift = 7.5e6;
f1_shift = -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');
mat2wv(s1, 'ofdm_pilots_sync_30MHz.wv', sample_rate, 1);
save('ofdm_pilots_sync_30MHz.mat','-v7','s','f1','f2','num_carriers','num_zeros','prefix_length','num_symbols_frame','preamble_length');
mat2wv(s, 'ofdm_pilots_sync_30MHz.wv', sample_rate, 1);
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