3 * Copyright 2007 Free Software Foundation, Inc.
5 * This file is part of GNU Radio
7 * GNU Radio is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 3, or (at your option)
12 * GNU Radio is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with GNU Radio; see the file COPYING. If not, write to
19 * the Free Software Foundation, Inc., 51 Franklin Street,
20 * Boston, MA 02110-1301, USA.
27 #include <gr_ofdm_qpsk_mapper.h>
28 #include <gr_io_signature.h>
31 gr_ofdm_qpsk_mapper_sptr
32 gr_make_ofdm_qpsk_mapper (unsigned int msgq_limit,
33 unsigned int occupied_carriers, unsigned int fft_length)
35 return gr_ofdm_qpsk_mapper_sptr (new gr_ofdm_qpsk_mapper (msgq_limit, occupied_carriers, fft_length));
38 // Consumes 1 packet and produces as many OFDM symbols of fft_length to hold the full packet
39 gr_ofdm_qpsk_mapper::gr_ofdm_qpsk_mapper (unsigned int msgq_limit,
40 unsigned int occupied_carriers, unsigned int fft_length)
41 : gr_sync_block ("ofdm_qpsk_mapper",
42 gr_make_io_signature (0, 0, 0),
43 gr_make_io_signature2 (1, 2, sizeof(gr_complex)*fft_length, sizeof(char))),
44 d_msgq(gr_make_msg_queue(msgq_limit)), d_msg_offset(0), d_eof(false),
45 d_occupied_carriers(occupied_carriers),
46 d_fft_length(fft_length),
50 if (!(d_occupied_carriers <= d_fft_length))
51 throw std::invalid_argument("gr_ofdm_qpsk_mapper: occupied carriers must be <= fft_length");
54 gr_ofdm_qpsk_mapper::~gr_ofdm_qpsk_mapper(void)
63 return gr_complex((0.707)*(-1 + 2*r1),(0.707)*(-1 + 2*r2));
67 gr_ofdm_qpsk_mapper::work(int noutput_items,
68 gr_vector_const_void_star &input_items,
69 gr_vector_void_star &output_items)
71 gr_complex *out = (gr_complex *)output_items[0];
74 unsigned int unoccupied_carriers = d_fft_length - d_occupied_carriers;
75 unsigned int zeros_on_left = (unsigned)ceil(unoccupied_carriers/2.0);
77 //printf("OFDM QPSK Mapper: ninput_items: %d noutput_items: %d\n", ninput_items[0], noutput_items);
84 d_msg = d_msgq->delete_head(); // block, waiting for a message
87 d_pending_flag = 1; // new packet, write start of packet flag
89 if((d_msg->length() == 0) && (d_msg->type() == 1)) {
91 return -1; // We're done; no more messages coming.
96 if(output_items.size() == 2)
97 out_flag = (char *) output_items[1];
100 // Build a single symbol:
103 // Initialize all bins to 0 to set unused carriers
104 memset(out, 0, d_fft_length*sizeof(gr_complex));
107 while((d_msg_offset < d_msg->length()) && (i < d_occupied_carriers)) {
108 unsigned char bit0 = (d_msg->msg()[d_msg_offset] >> (d_bit_offset)) & 0x01;
111 unsigned char bit1 = (d_msg->msg()[d_msg_offset] >> (d_bit_offset)) & 0x01;
114 out[i + zeros_on_left] = gr_complex((0.707)*(-1+2*(bit0)), (0.707)*(-1+2*(bit1)) );
116 if(d_bit_offset == 8) {
122 // Ran out of data to put in symbol
123 if (d_msg_offset == d_msg->length()) {
124 while(i < d_occupied_carriers) { // finish filling out the symbol
125 out[i + zeros_on_left] = randombit();
129 if (d_msg->type() == 1) // type == 1 sets EOF
131 d_msg.reset(); // finished packet, free message
132 assert(d_bit_offset == 0);
136 out_flag[0] = d_pending_flag;
139 return 1; // produced symbol