diff options
Diffstat (limited to 'gr-digital/lib/digital_ofdm_insert_preamble.cc')
| -rw-r--r-- | gr-digital/lib/digital_ofdm_insert_preamble.cc | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/gr-digital/lib/digital_ofdm_insert_preamble.cc b/gr-digital/lib/digital_ofdm_insert_preamble.cc new file mode 100644 index 000000000..a46133643 --- /dev/null +++ b/gr-digital/lib/digital_ofdm_insert_preamble.cc @@ -0,0 +1,187 @@ +/* -*- c++ -*- */ +/* + * Copyright 2007,2010,2011 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 this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif + +#include <digital_ofdm_insert_preamble.h> +#include <gr_io_signature.h> +#include <stdexcept> +#include <iostream> +#include <string.h> + +digital_ofdm_insert_preamble_sptr +digital_make_ofdm_insert_preamble(int fft_length, + const std::vector<std::vector<gr_complex> > &preamble) +{ + return gnuradio::get_initial_sptr(new digital_ofdm_insert_preamble(fft_length, + preamble)); +} + +digital_ofdm_insert_preamble::digital_ofdm_insert_preamble + (int fft_length, + const std::vector<std::vector<gr_complex> > &preamble) + : gr_block("ofdm_insert_preamble", + gr_make_io_signature2(2, 2, + sizeof(gr_complex)*fft_length, + sizeof(char)), + gr_make_io_signature2(1, 2, + sizeof(gr_complex)*fft_length, + sizeof(char))), + d_fft_length(fft_length), + d_preamble(preamble), + d_state(ST_IDLE), + d_nsymbols_output(0), + d_pending_flag(0) +{ + // sanity check preamble symbols + for (size_t i = 0; i < d_preamble.size(); i++){ + if (d_preamble[i].size() != (size_t) d_fft_length) + throw std::invalid_argument("digital_ofdm_insert_preamble: invalid length for preamble symbol"); + } + + enter_idle(); +} + + +digital_ofdm_insert_preamble::~digital_ofdm_insert_preamble() +{ +} + +int +digital_ofdm_insert_preamble::general_work (int noutput_items, + gr_vector_int &ninput_items_v, + gr_vector_const_void_star &input_items, + gr_vector_void_star &output_items) +{ + int ninput_items = std::min(ninput_items_v[0], ninput_items_v[1]); + const gr_complex *in_sym = (const gr_complex *) input_items[0]; + const unsigned char *in_flag = (const unsigned char *) input_items[1]; + + gr_complex *out_sym = (gr_complex *) output_items[0]; + unsigned char *out_flag = 0; + if (output_items.size() == 2) + out_flag = (unsigned char *) output_items[1]; + + + int no = 0; // number items output + int ni = 0; // number items read from input + + +#define write_out_flag() \ + do { if (out_flag) \ + out_flag[no] = d_pending_flag; \ + d_pending_flag = 0; \ + } while(0) + + + while (no < noutput_items && ni < ninput_items){ + switch(d_state){ + case ST_IDLE: + if (in_flag[ni] & 0x1) // this is first symbol of new payload + enter_preamble(); + else + ni++; // eat one input symbol + break; + + case ST_PREAMBLE: + assert(in_flag[ni] & 0x1); + if (d_nsymbols_output >= (int) d_preamble.size()){ + // we've output all the preamble + enter_first_payload(); + } + else { + memcpy(&out_sym[no * d_fft_length], + &d_preamble[d_nsymbols_output][0], + d_fft_length*sizeof(gr_complex)); + + write_out_flag(); + no++; + d_nsymbols_output++; + } + break; + + case ST_FIRST_PAYLOAD: + // copy first payload symbol from input to output + memcpy(&out_sym[no * d_fft_length], + &in_sym[ni * d_fft_length], + d_fft_length * sizeof(gr_complex)); + + write_out_flag(); + no++; + ni++; + enter_payload(); + break; + + case ST_PAYLOAD: + if (in_flag[ni] & 0x1){ // this is first symbol of a new payload + enter_preamble(); + break; + } + + // copy a symbol from input to output + memcpy(&out_sym[no * d_fft_length], + &in_sym[ni * d_fft_length], + d_fft_length * sizeof(gr_complex)); + + write_out_flag(); + no++; + ni++; + break; + + default: + std::cerr << "digital_ofdm_insert_preamble: (can't happen) invalid state, resetting\n"; + enter_idle(); + } + } + + consume_each(ni); + return no; +} + +void +digital_ofdm_insert_preamble::enter_idle() +{ + d_state = ST_IDLE; + d_nsymbols_output = 0; + d_pending_flag = 0; +} + +void +digital_ofdm_insert_preamble::enter_preamble() +{ + d_state = ST_PREAMBLE; + d_nsymbols_output = 0; + d_pending_flag = 1; +} + +void +digital_ofdm_insert_preamble::enter_first_payload() +{ + d_state = ST_FIRST_PAYLOAD; +} + +void +digital_ofdm_insert_preamble::enter_payload() +{ + d_state = ST_PAYLOAD; +} |