From 04c193d15192d926c7349ca4a9362d721fe0db6c Mon Sep 17 00:00:00 2001
From: Piotr Krysik <perper@o2.pl>
Date: Fri, 10 Apr 2009 17:22:31 +0200
Subject: added frequency burst detection, but not yet finished
---
configure.ac | 3 +-
src/Makefile.am | 2 +-
src/lib/gsm_receiver_cf.cc | 141 +++++++++++++++++++++++++++------------------
src/lib/gsm_receiver_cf.h | 19 +++---
4 files changed, 100 insertions(+), 65 deletions(-)
diff --git a/configure.ac b/configure.ac
index b3b1f16..556d5c5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -105,10 +105,11 @@ AC_CONFIG_FILES([\
config/Makefile \
src/Makefile \
src/lib/Makefile \
+ src/python/Makefile \
gsm-receiver.pc \
+
])
# doc/Makefile \
-# src/python/Makefile \
# src/python/run_tests \
dnl run_tests is created from run_tests.in. Make it executable.
diff --git a/src/Makefile.am b/src/Makefile.am
index 3ff9849..79cfa3e 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -19,5 +19,5 @@
# Boston, MA 02110-1301, USA.
#
-SUBDIRS = lib
+SUBDIRS = lib python
diff --git a/src/lib/gsm_receiver_cf.cc b/src/lib/gsm_receiver_cf.cc
index e478c66..206bd5e 100644
--- a/src/lib/gsm_receiver_cf.cc
+++ b/src/lib/gsm_receiver_cf.cc
@@ -1,19 +1,19 @@
/* -*- c++ -*- */
/*
* Copyright 2004 Free Software Foundation, Inc.
- *
+ *
* This file is part of GNU Radio
- *
+ *
* GNU Radio is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3, or (at your option)
* any later version.
- *
+ *
* GNU Radio is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
- *
+ *
* You should have received a copy of the GNU General Public License
* along with GNU Radio; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
@@ -26,94 +26,123 @@
#include <gsm_receiver_cf.h>
#include <gr_io_signature.h>
+#include <gr_math.h>
+#include <gsm_constants.h>
+#include <Assert.h>
-gsm_receiver_cf_sptr
-gsm_make_receiver_cf ()
+
+gsm_receiver_cf_sptr
+gsm_make_receiver_cf(int osr)
{
- return gsm_receiver_cf_sptr (new gsm_receiver_cf ());
+ return gsm_receiver_cf_sptr(new gsm_receiver_cf(osr));
}
-static const int MIN_IN = 1; // mininum number of input streams
-static const int MAX_IN = 1; // maximum number of input streams
-static const int MIN_OUT = 1; // minimum number of output streams
-static const int MAX_OUT = 1; // maximum number of output streams
+static const int MIN_IN = 1; // mininum number of input streams
+static const int MAX_IN = 1; // maximum number of input streams
+static const int MIN_OUT = 0; // minimum number of output streams
+static const int MAX_OUT = 1; // maximum number of output streams
/*
* The private constructor
*/
-gsm_receiver_cf::gsm_receiver_cf ()
- : gr_block ("gsm_receiver",
- gr_make_io_signature (MIN_IN, MAX_IN, sizeof (gr_complex)),
- gr_make_io_signature (MIN_OUT, MAX_OUT, sizeof (float)))
+gsm_receiver_cf::gsm_receiver_cf(int osr)
+ : gr_block("gsm_receiver",
+ gr_make_io_signature(MIN_IN, MAX_IN, sizeof(gr_complex)),
+ gr_make_io_signature(MIN_OUT, MAX_OUT, 142 * sizeof(float))),
+ d_counter(0)
{
}
/*
* Virtual destructor.
*/
-gsm_receiver_cf::~gsm_receiver_cf ()
+gsm_receiver_cf::~gsm_receiver_cf()
+{
+}
+
+void gsm_receiver_cf::forecast(int noutput_items, gr_vector_int &ninput_items_required)
{
+ ninput_items_required[0] = noutput_items * TS_BITS; //TODO include oversampling ratio here
}
-int
-gsm_receiver_cf::general_work (int noutput_items,
- gr_vector_int &ninput_items,
- gr_vector_const_void_star &input_items,
- gr_vector_void_star &output_items)
+int
+gsm_receiver_cf::general_work(int noutput_items,
+ gr_vector_int &ninput_items,
+ gr_vector_const_void_star &input_items,
+ gr_vector_void_star &output_items)
{
- const float *in = (const float *) input_items[0];
+ const gr_complex *in = (const gr_complex *) input_items[0];
float *out = (float *) output_items[0];
- for (int i = 0; i < noutput_items; i++){
- out[i] = in[i] * in[i];
- }
+// DCOUT(ninput_items[0]);
+// DCOUT(noutput_items);
- consume_each (noutput_items);
- return noutput_items;
+ d_return = 0; //!
+ int start_pos = find_fcch_burst(in, ninput_items[0]);
+ for (int i = 0; i < TS_BITS; i++) {
+ out[i] = d_phase_diff_buffer[i+start_pos-USEFUL_BITS];
+ }
+ consume_each(start_pos);
+ d_counter += start_pos;
+ return d_return;
}
-
-bool gsm_receiver_cf::get_fcch_burst()
+int gsm_receiver_cf::find_fcch_burst(const gr_complex *in, const int nitems)
{
+ for (int i = 0; (i < nitems - 1) && (i < BUFFER_SIZE); i++) {
+ gr_complex conjprod = in[i+1] * conj(in[i]);
+ float diff_angle = gr_fast_atan2f(imag(conjprod), real(conjprod));
+ d_phase_diff_buffer[i] = diff_angle;
+ }
+
int hit_count = 0;
int miss_count = 0;
int start_pos = -1;
-/*
- for ( int i=0; i < BBUF_SIZE; i++ ) {
- if ( d_burst_buffer[i] > 0 ) {
- if ( ! hit_count++ )
- start_pos = i;
- } else {
- if ( hit_count >= FCCH_HITS_NEEDED ) {
- break;
- } else
- if ( ++miss_count > FCCH_MAX_MISSES ) {
- start_pos = -1;
- hit_count = miss_count = 0;
- }
- }
+
+ d_return = 0;//!
+
+ for (int i = 0; ; i++) {
+ if (i > nitems - USEFUL_BITS - 1) {
+ start_pos = nitems - USEFUL_BITS - 1;
+ break;
}
- //Do we have a match?
- if ( start_pos >= 0 ) {
+ if (d_phase_diff_buffer[i] > 0) {
+ if (! hit_count) {
+ start_pos = i+USEFUL_BITS;
+ }
+ hit_count++;
+ } else if (hit_count >= FCCH_HITS_NEEDED) {
+ DCOUT("znalezione fcch na pozycji" << d_counter+start_pos-USEFUL_BITS);
+ d_return = 1;//!
+ break;
+ } else if (++miss_count > FCCH_MAX_MISSES) {
+ start_pos = -1;
+ hit_count = miss_count = 0;
+ }
+ }
+
+ /*
+ //Do we have a match?
+ if (start_pos >= 0) {
//Is it within range? (we know it's long enough then too)
- if ( start_pos < 2*MAX_CORR_DIST ) {
- d_burst_start = start_pos;
- d_bbuf_pos = 0; //load buffer from start
- return FCCH;
-
- } else {
- //TODO: don't shift a tiny amount
- shift_burst( start_pos - MAX_CORR_DIST );
- }
+ if (start_pos < 2*MAX_CORR_DIST) {
+ d_burst_start = start_pos;
+ d_bbuf_pos = 0; //load buffer from start
+ return FCCH;
+ } else {
+ //TODO: don't shift a tiny amount
+ shift_burst(start_pos - MAX_CORR_DIST);
+ }
} else {
//Didn't find anything
d_burst_start = MAX_CORR_DIST;
d_bbuf_pos = 0; //load buffer from start
}
+ */
+ //DCOUT("start_pos: " << start_pos);
- return UNKNOWN;
-*/
+ return start_pos;
}
diff --git a/src/lib/gsm_receiver_cf.h b/src/lib/gsm_receiver_cf.h
index 7067fb2..5bc7617 100644
--- a/src/lib/gsm_receiver_cf.h
+++ b/src/lib/gsm_receiver_cf.h
@@ -25,6 +25,8 @@
#include <gr_block.h>
#include <gr_complex.h>
+#define BUFFER_SIZE 4096
+
class gsm_receiver_cf;
/*
@@ -47,26 +49,29 @@ typedef boost::shared_ptr<gsm_receiver_cf> gsm_receiver_cf_sptr;
* constructor is private. howto_make_square_ff is the public
* interface for creating new instances.
*/
-gsm_receiver_cf_sptr gsm_make_receiver_cf();
+gsm_receiver_cf_sptr gsm_make_receiver_cf( int osr );
/*!
* \brief Receives fcch
* \ingroup block
- * \sa
+ * \sa
*/
class gsm_receiver_cf : public gr_block
{
private:
- friend gsm_receiver_cf_sptr gsm_make_receiver_cf();
-
- gsm_receiver_cf();
- bool get_fcch_burst();
+ int d_counter;
+ int d_return;
+ float d_phase_diff_buffer[BUFFER_SIZE];
+
+ friend gsm_receiver_cf_sptr gsm_make_receiver_cf( int osr );
+ gsm_receiver_cf( int osr );
+ int find_fcch_burst( const gr_complex *in, const int items );
public:
~gsm_receiver_cf();
-
+ void forecast( int noutput_items, gr_vector_int &ninput_items_required );
int general_work( int noutput_items,
gr_vector_int &ninput_items,
gr_vector_const_void_star &input_items,
--
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