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Diffstat (limited to 'gr-digital/lib/header_format_ofdm.cc')
| -rw-r--r-- | gr-digital/lib/header_format_ofdm.cc | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/gr-digital/lib/header_format_ofdm.cc b/gr-digital/lib/header_format_ofdm.cc new file mode 100644 index 0000000000..acaf53be67 --- /dev/null +++ b/gr-digital/lib/header_format_ofdm.cc @@ -0,0 +1,180 @@ +/* -*- c++ -*- */ +/* Copyright 2016 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, + * Boston, MA 02110-1301, USA. + */ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#include <string.h> +#include <volk/volk.h> +#include <gnuradio/digital/header_format_ofdm.h> +#include <gnuradio/digital/header_buffer.h> +#include <gnuradio/digital/lfsr.h> + +namespace gr { + namespace digital { + + header_format_ofdm::sptr + header_format_ofdm::make(const std::vector<std::vector<int> > &occupied_carriers, + int n_syms, + const std::string &len_key_name, + const std::string &frame_key_name, + const std::string &num_key_name, + int bits_per_header_sym, + int bits_per_payload_sym, + bool scramble_header) + { + return header_format_ofdm::sptr + (new header_format_ofdm(occupied_carriers, n_syms, + len_key_name, frame_key_name, num_key_name, + bits_per_header_sym, + bits_per_payload_sym, + scramble_header)); + } + + header_format_ofdm::header_format_ofdm(const std::vector<std::vector<int> > &occupied_carriers, + int n_syms, + const std::string &len_key_name, + const std::string &frame_key_name, + const std::string &num_key_name, + int bits_per_header_sym, + int bits_per_payload_sym, + bool scramble_header) + : header_format_crc(len_key_name, num_key_name), + d_frame_key_name(pmt::intern(frame_key_name)), + d_occupied_carriers(occupied_carriers), + d_bits_per_payload_sym(bits_per_payload_sym) + { + d_header_len = 0; + for(int i = 0; i < n_syms; i++) { + d_header_len += occupied_carriers[i].size(); + } + + d_syms_per_set = 0; + for(unsigned i = 0; i < d_occupied_carriers.size(); i++) { + d_syms_per_set += d_occupied_carriers[i].size(); + } + + // Init scrambler mask + d_scramble_mask = std::vector<uint8_t>(header_nbits(), 0); + if(scramble_header) { + // These are just random values which already have OK PAPR: + gr::digital::lfsr shift_reg(0x8a, 0x6f, 7); + for(size_t i = 0; i < header_nbytes(); i++) { + for(int k = 0; k < bits_per_header_sym; k++) { + d_scramble_mask[i] ^= shift_reg.next_bit() << k; + } + } + } + } + + header_format_ofdm::~header_format_ofdm() + { + } + + bool + header_format_ofdm::format(int nbytes_in, + const unsigned char *input, + pmt::pmt_t &output, + pmt::pmt_t &info) + { + bool ret_val = header_format_crc::format(nbytes_in, input, + output, info); + + //size_t len; + //uint8_t *out = pmt::u8vector_writable_elements(output, len); + //for(size_t i = 0; i < len; i++) { + // out[i] ^= d_scramble_mask[i]; + //} + + return ret_val; + } + + bool + header_format_ofdm::parse(int nbits_in, + const unsigned char *input, + std::vector<pmt::pmt_t> &info, + int &nbits_processed) + { + int index = 0; + while(nbits_processed <= nbits_in) { + d_hdr_reg.insert_bit(input[nbits_processed++] ^ d_scramble_mask[index++]); + if(d_hdr_reg.length() == header_nbits()) { + if(header_ok()) { + int payload_len = header_payload(); + enter_have_header(payload_len); + info.push_back(d_info); + d_hdr_reg.clear(); + return true; + } + else { + d_hdr_reg.clear(); + return false; + } + break; + } + } + + return true; + } + + size_t + header_format_ofdm::header_nbits() const + { + return d_header_len; + } + + int + header_format_ofdm::header_payload() + { + uint32_t pkt = d_hdr_reg.extract_field32(0, 24, true); + uint16_t pktlen = static_cast<uint16_t>((pkt >> 8) & 0x0fff); + uint16_t pktnum = static_cast<uint16_t>((pkt >> 20) & 0x0fff); + + // Convert num bytes to num complex symbols in payload + pktlen *= 8; + uint16_t pldlen = pktlen / d_bits_per_payload_sym; + if(pktlen % d_bits_per_payload_sym) { + pldlen++; + } + + // frame_len = # of OFDM symbols in this frame + int framelen = pldlen / d_syms_per_set; + int k = 0; + int i = framelen * d_syms_per_set; + while(i < pldlen) { + framelen++; + //i += d_occupied_carriers[k++].size(); + i += d_occupied_carriers[k].size(); + } + + d_info = pmt::make_dict(); + d_info = pmt::dict_add(d_info, d_len_key_name, + pmt::from_long(pldlen)); + d_info = pmt::dict_add(d_info, d_num_key_name, + pmt::from_long(pktnum)); + d_info = pmt::dict_add(d_info, d_frame_key_name, + pmt::from_long(framelen)); + return static_cast<int>(pldlen); + } + + } /* namespace digital */ +} /* namespace gr */ |