From 473374d0c27053da1032b10908b8c1079f5f7e8f Mon Sep 17 00:00:00 2001
From: Jens Ahrensfeld <jens@jayfield.org>
Date: Wed, 6 May 2015 19:42:43 +0000
Subject: [PATCH] [RX] - added SFO estimation (Zwischenstand)

git-svn-id: http://moon:8086/svn/matlab/trunk@85 801c6759-fa7c-4059-a304-17956f83a07c
---
 ofdm/ofdm_rx.m | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/ofdm/ofdm_rx.m b/ofdm/ofdm_rx.m
index 714101b..dab2ba0 100644
--- a/ofdm/ofdm_rx.m
+++ b/ofdm/ofdm_rx.m
@@ -105,6 +105,7 @@ phi_foff = 0;
 phi_track = 0;
 df_track = 0;
 df_track_ = [];
+sfo_ = [];
 max_H_plot = 0;
 
 fileRemain = wav_size;
@@ -360,13 +361,24 @@ while((fileRemain > fileChunkSize) | (buf_recv.len() > 2*N))	% ToDo: don't leave
 					H_too_small_index = find( abs(H_syms)<equalizer.eps_abs_h );
 					H_syms( H_too_small_index ) = equalizer.eps_abs_h;
 
+					% SFO
+					% CTO per carrier
+					c_sfo = H_syms.' .* conj(H_raw(carrier_indexes)) + equalizer.eps_abs_h;
+					sum_sfoL = sum(c_sfo(1:103));
+					sum_sfoH = sum(c_sfo(105:207));
+					sfoL = angle(sum_sfoL);
+					sfoH = angle(sum_sfoH);
+					sfo_ = [sfo_ 2*fs/(2*pi*N)*(sfoH - sfoL)];
+
 					% equalize symbol
 					sym_eq = sym ./ H_syms;
 					if strcmpi(plot_mode, 'h_pilots')
-						subplot(2, 1, 1)
+						subplot(3, 1, 1)
 						plot(1:length(Hr), abs(Hr), 'b-', 1:length(H_pilots), abs(H_pilots), 'r-'); grid; 
-						subplot(2, 1, 2)
+						subplot(3, 1, 2)
 						plot(1:length(Hr), angle(Hr), 'b-', 1:length(H_pilots), angle(H_pilots), 'r-'); grid; 
+						subplot(3, 1, 3)
+						plot(1:length(c_sfo), angle(c_sfo), 'b-'); grid; 
 						title(str);
 						pause(0.01);
 					end
@@ -431,6 +443,9 @@ subplot(4, 1, 4)
 plot(0:length(df_track_)-1, df_track_); grid; title('df_{track}')
 hold on;
 
+figure;
+plot(0:length(sfo_)-1, sfo_); grid; title('SFO');
+
 % --------------------------------------------------------------
 % Write wave files
 % --------------------------------------------------------------