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/* -*- c++ -*- */
/*
* @file
* @author Piotr Krysik <pkrysik@stud.elka.pw.edu.pl>
* @section LICENSE
*
* This program 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.
*
* This program 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 this program; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#ifndef INCLUDED_GSM_RECEIVER_CF_H
#define INCLUDED_GSM_RECEIVER_CF_H
#include <vector>
#include <list>
#include <gr_block.h>
#include <gr_complex.h>
#include <gr_feval.h>
#include <gsm_constants.h>
#include <gsm_receiver_config.h>
#include <gsmstack.h> //TODO: remember to remove this line in the future!
#include "GSML1FEC.h" //!!
#include <a5-1-2.h>//!!
#include <string>//!!
#include <map>//!!
class gsm_receiver_cf;
typedef boost::shared_ptr<gsm_receiver_cf> gsm_receiver_cf_sptr;
typedef std::vector<gr_complex> vector_complex;
gsm_receiver_cf_sptr gsm_make_receiver_cf(gr_feval_dd *tuner, gr_feval_dd *synchronizer, int osr, std::string key);
/** GSM Receiver GNU Radio block
*
* GSM Receiver class supports frequency correction, synchronisation and
* MLSE (Maximum Likelihood Sequence Estimation) estimation of synchronisation
* bursts and normal bursts.
* \ingroup block
*/
class gsm_receiver_cf : public gr_block
{
private:
std::map<char,int> d_hex_to_int;
FILE * d_gsm_file; //!!
byte d_KC[8]; //!!
GSM::TCHFACCHL1Decoder d_tch_decoder1; //!!
GSM::TCHFACCHL1Decoder d_tch_decoder2; //!!
GSM::TCHFACCHL1Decoder d_tch_decoder3; //!!
GSM::TCHFACCHL1Decoder d_tch_decoder4; //!!
GSM::TCHFACCHL1Decoder d_tch_decoder5; //!!
GSM::TCHFACCHL1Decoder d_tch_decoder6; //!!
GSM::TCHFACCHL1Decoder d_tch_decoder7; //!!
/**@name Configuration of the receiver */
//@{
const int d_OSR; ///< oversampling ratio
const int d_chan_imp_length; ///< channel impulse length
//@}
gr_complex d_sch_training_seq[N_SYNC_BITS]; ///<encoded training sequence of a SCH burst
gr_complex d_norm_training_seq[TRAIN_SEQ_NUM][N_TRAIN_BITS]; ///<encoded training sequences of a normal bursts and dummy bursts
gr_feval_dd *d_tuner; ///<callback to a python object which is used for frequency tunning
gr_feval_dd *d_synchronizer; ///<callback to a python object which is used to correct offset of USRP's internal clock
/** Countes samples consumed by the receiver
*
* It is used in beetween find_fcch_burst and reach_sch_burst calls.
* My intention was to synchronize this counter with some internal sample
* counter of the USRP. Simple access to such USRP's counter isn't possible
* so this variable isn't used in the "synchronized" state of the receiver yet.
*/
unsigned d_counter;
/**@name Variables used to store result of the find_fcch_burst fuction */
//@{
unsigned d_fcch_start_pos; ///< position of the first sample of the fcch burst
float d_freq_offset; ///< frequency offset of the received signal
//@}
std::list<double> d_freq_offset_vals;
/**@name Identifiers of the BTS extracted from the SCH burst */
//@{
int d_ncc; ///< network color code
int d_bcc; ///< base station color code
//@}
/**@name Internal state of the gsm receiver */
//@{
enum states {
first_fcch_search, next_fcch_search, sch_search, // synchronization search part
synchronized // receiver is synchronized in this state
} d_state;
//@}
/**@name Variables which make internal state in the "synchronized" state */
//@{
burst_counter d_burst_nr; ///< frame number and timeslot number
channel_configuration d_channel_conf; ///< mapping of burst_counter to burst_type
//@}
unsigned d_failed_sch; ///< number of subsequent erroneous SCH bursts
// GSM Stack
GS_CTX d_gs_ctx;//TODO: remove it! it'a not right place for a decoder
friend gsm_receiver_cf_sptr gsm_make_receiver_cf(gr_feval_dd *tuner, gr_feval_dd *synchronizer, int osr, std::string key);
gsm_receiver_cf(gr_feval_dd *tuner, gr_feval_dd *synchronizer, int osr, std::string key);
/** Function whis is used to search a FCCH burst and to compute frequency offset before
* "synchronized" state of the receiver
*
* TODO: Describe the FCCH search algorithm in the documentation
* @param input vector with input signal
* @param nitems number of samples in the input vector
* @return
*/
bool find_fcch_burst(const gr_complex *input, const int nitems);
/** Computes frequency offset from FCCH burst samples
*
* @param input vector with input samples
* @param first_sample number of the first sample of the FCCH busrt
* @param last_sample number of the last sample of the FCCH busrt
* @return frequency offset
*/
double compute_freq_offset(const gr_complex * input, unsigned first_sample, unsigned last_sample);
/** Calls d_tuner's method to set frequency offset from Python level
*
* @param freq_offset absolute frequency offset of the received signal
*/
void set_frequency(double freq_offset);
/** Computes angle between two complex numbers
*
* @param val1 first complex number
* @param val2 second complex number
* @return
*/
inline float compute_phase_diff(gr_complex val1, gr_complex val2);
/** Function whis is used to get near to SCH burst
*
* @param nitems number of samples in the gsm_receiver's buffer
* @return true if SCH burst is near, false otherwise
*/
bool reach_sch_burst(const int nitems);
/** Extracts channel impulse response from a SCH burst and computes first sample number of this burst
*
* @param input vector with input samples
* @param chan_imp_resp complex vector where channel impulse response will be stored
* @return number of first sample of the burst
*/
int get_sch_chan_imp_resp(const gr_complex *input, gr_complex * chan_imp_resp);
/** MLSE detection of a burst bits
*
* Detects bits of burst using viterbi algorithm.
* @param input vector with input samples
* @param chan_imp_resp vector with the channel impulse response
* @param burst_start number of the first sample of the burst
* @param output_binary vector with output bits
*/
void detect_burst(const gr_complex * input, gr_complex * chan_imp_resp, int burst_start, unsigned char * output_binary);
/** Encodes differentially input bits and maps them into MSK states
*
* @param input vector with input bits
* @param nitems number of samples in the "input" vector
* @param gmsk_output bits mapped into MSK states
* @param start_point first state
*/
void gmsk_mapper(const unsigned char * input, int nitems, gr_complex * gmsk_output, gr_complex start_point);
/** Correlates MSK mapped sequence with input signal
*
* @param sequence MKS mapped sequence
* @param length length of the sequence
* @param input_signal vector with input samples
* @return correlation value
*/
gr_complex correlate_sequence(const gr_complex * sequence, int length, const gr_complex * input);
/** Computes autocorrelation of input vector for positive arguments
*
* @param input vector with input samples
* @param out output vector
* @param nitems length of the input vector
*/
inline void autocorrelation(const gr_complex * input, gr_complex * out, int nitems);
/** Filters input signal through channel impulse response
*
* @param input vector with input samples
* @param nitems number of samples to pass through filter
* @param filter filter taps - channel impulse response
* @param filter_length nember of filter taps
* @param output vector with filtered samples
*/
inline void mafi(const gr_complex * input, int nitems, gr_complex * filter, int filter_length, gr_complex * output);
/** Extracts channel impulse response from a normal burst and computes first sample number of this burst
*
* @param input vector with input samples
* @param chan_imp_resp complex vector where channel impulse response will be stored
* @param search_range possible absolute offset of a channel impulse response start
* @param bcc base station color code - number of a training sequence
* @return first sample number of normal burst
*/
int get_norm_chan_imp_resp(const gr_complex * input, gr_complex * chan_imp_resp, int bcc);
/**
*
*/
void read_key(std::string key);
/**
*
*/
void process_normal_burst(burst_counter burst_nr, const unsigned char * burst_binary);
/**
*
*/
void configure_receiver();
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,
gr_vector_void_star &output_items);
};
#endif /* INCLUDED_GSM_RECEIVER_CF_H */
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