- RX added wiener filtering and other stuff

- Tx reordered generation of pilots

git-svn-id: http://moon:8086/svn/matlab/trunk@41 801c6759-fa7c-4059-a304-17956f83a07c

ofdm/ofdm_rx.m

@@ -1,4 +1,4 @@
-function [x] = ofdm_rx(filename, foff, knoise_dB, with_cir)
+function [sym_out, H, W] = ofdm_rx(filename, foff, SNR, with_cir)
 %
 % Example: ofdm_rx('drm-15435-if.wav', -174.65, -400, 0)
 % Example: ofdm_tx(40, 1)
@@ -33,7 +33,7 @@ if (ndim == 2)
 elseif (ndim == 1)
     fprintf('Mode: Passband\n');
     x = xwav.*exp(-j*(2*pi*(0.25-foff/fs_)*(0:len-1)'));
-    hlp = FIRCalcLowpass(12000/fs_, 33);
+    hlp = FIRCalcLowpass(12000/fs_, 15);
     x = filter(hlp, 1, x);
 	
 	% Downsample
@@ -50,9 +50,7 @@ x = x./max(abs(x));
 xout = [real(x) imag(x)];
 wavwrite(xout,fs,nbits,'ofdm_rx.wav');
 
-x = x +  sqrt(0.5)*10^(knoise_dB/20)*(randn(size(x)) + j*randn(size(x)));
-
-
+x = awgn(x, SNR, 'measured');
 K = fix((length(x))/(N+Ng))-1;
 
 % Timing coarse
@@ -190,9 +188,10 @@ end
 bins = c2i(N, carrier_time);
 kc_max = -1000;
 n_max = 0;
+skip_syms = 15*4;
 for n=0:15-1
     frame_timing_Z = 0;
-    k = 200+n;
+    k = skip_syms+n;
     for m=1:2
         [kc valid frame_timing_Z] = timing_frame(Z_(bins, k)', bins, 15, frame_timing_Z);
         k = k + 15;
@@ -207,7 +206,7 @@ end
 frame_start = n_max;
 
 figure;
-start = 200+frame_start;
+start = skip_syms+frame_start;
 Z_timing = Z_(bins, start:15:length(Z_))';
 plot(real(Z_timing), imag(Z_timing), '+'); grid; title('SymPilot_{Time}'); 
 maxZ = max(max(abs(Z_timing)));
@@ -217,47 +216,73 @@ else
     axis([-maxZ maxZ -maxZ maxZ]);
 end
 
+W = calcWiener(drm_mode, drm_bw);
+
 figure;
 % Detect scattered gain pilots
 sym_count = 0;
-start = 200+frame_start;
+win_count = 0;
+start = skip_syms+frame_start;
 H = zeros(N, 1);
 sym_H = [];
+sym_out = [];
+kk = 1;
+G = [];
+bin = c2i(N, 13);
+Hraw = [];
+
+symbols_per_frame = 15;
+symbols_to_delay = ofdm_drm_params.y;
+symbol_counter = 0;
+frames_per_window = 2*ofdm_drm_params.y
+H_gain_cell = cell (frames_per_window, 1);
+H_gain_carriers_cell = cell (frames_per_window, 1);
 for k=start:length(Z_)
-    [carrier_gain, phi_gain, mag_gain] = getRefGain(ofdm_spec_occ, ofdm_drm_params, sym_count);
+    
+    %shifted symbol index
+    nn = rem(k-1-symbols_to_delay + symbols_per_frame, symbols_per_frame);
+    n = rem(nn, ofdm_drm_params.y);
+    m = floor(nn/ofdm_drm_params.y);
+
+    [carrier_gain, phi_gain, mag_gain] = getRefGain(ofdm_drm_params, ofdm_spec_occ, symbol_counter); symbol_counter = symbol_counter + 1;
     carrier_gain_bins = c2i(N, carrier_gain);
-    Hp = Z_(carrier_gain_bins, k)./(mag_gain.*exp(-j*2*pi*phi_gain/1024))';
-    H(carrier_gain_bins) = Hp;
-    sym_count_str = sprintf('%d', sym_count);
-    if 0
-        plot(abs(Hp)); grid; title(sym_count_str);
-        pause(0.1);
-    end
-
-    if (sym_count < 14)
-        sym_count = sym_count+1;
-    else
-        H(1:2:N) = H(2:2:length(H));
+    Hp = Z_(carrier_gain_bins, k)./(mag_gain.*exp(j*2*pi*phi_gain/1024)).';
+    
+    H_gain_cell{win_count+1} = transpose(Z_(carrier_gain_bins, k)./(mag_gain.*exp(j*2*pi*phi_gain/1024)).');
+    ii = 1+mod(0+win_count+(0:frames_per_window-1), frames_per_window);
+    H_gain = [H_gain_cell{ii}];
+    H_gain_carriers_cell{win_count+1} = carrier_gain;
+    if length(H_gain) == 208
         if 1
-%            G = ones(size(H));
-%            G = 1./(H+1e-6);
-            G = (conj(H)*1)./(abs(H).^2 * 1 + sigma_Hp(1));
-            subplot(4, 1, 1)
-            plot(abs(spec_order(N, H))); grid; title('abs(H)');
-            subplot(4, 1, 2)
-            plot(angle(spec_order(N, H))); grid; title('phi(H)');
-            subplot(4, 1, 3)
-            plot(abs(spec_order(N, G))); grid; title('abs(G)');
-            subplot(4, 1, 4)
-            plot(angle(spec_order(N, G))); grid; title('phi(G)');
+            H = H_gain*W{n+1};
+            ZZ = Z_(c2i(N, ofdm_spec_occ.kmin:ofdm_spec_occ.kmax), k).';
+            sym_out(:, kk) = ZZ ./ H;
+            if 1
+            subplot(2, 1, 1)
+            plot(abs(H)); grid; title('abs(H)');
+            subplot(2, 1, 2)
+            plot(angle(H)); grid; title('phi(H)');
+            else
+                hold on;
+                plot(sym_out(:, kk), '+');
+                hold off;
+                grid; title('Sym');
+            end
+            pause(0.01);
+        else
+            ii = [H_gain_carriers_cell{1:6}]
+            H = H_gain;
+            sym_out(:, kk) = 0;
+            subplot(2, 1, 1)
+            plot(abs(H)); grid; title('abs(H)');
+            subplot(2, 1, 2)
+            plot(angle(H)); grid; title('phi(H)');
             pause(0.01);
-
-            bin = c2i(N, 13);
-            sym_H = [sym_H Z_(bin, k).*G(bin)];
         end
-        H_gather = zeros(N, 1);
-        sym_count = 0;
-    end;
+    end
+    kk = kk + 1;
+    win_count = mod(win_count+1, frames_per_window);
+
 end
 
 figure;