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 2, 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_bpsk_mapper.h>
28 #include <gr_io_signature.h>
31 gr_ofdm_bpsk_mapper_sptr
32 gr_make_ofdm_bpsk_mapper (unsigned int msgq_limit,
33 unsigned int occupied_carriers, unsigned int fft_length)
35 return gr_ofdm_bpsk_mapper_sptr (new gr_ofdm_bpsk_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_bpsk_mapper::gr_ofdm_bpsk_mapper (unsigned int msgq_limit,
40 unsigned int occupied_carriers, unsigned int fft_length)
41 : gr_sync_block ("ofdm_bpsk_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_bpsk_mapper: occupied carriers must be <= fft_length");
54 gr_ofdm_bpsk_mapper::~gr_ofdm_bpsk_mapper(void)
62 return (float)(-1 + 2*r);
66 gr_ofdm_bpsk_mapper::work(int noutput_items,
67 gr_vector_const_void_star &input_items,
68 gr_vector_void_star &output_items)
70 gr_complex *out = (gr_complex *)output_items[0];
73 unsigned int unoccupied_carriers = d_fft_length - d_occupied_carriers;
74 unsigned int zeros_on_left = (unsigned)ceil(unoccupied_carriers/2.0);
76 //printf("OFDM BPSK Mapper: ninput_items: %d noutput_items: %d\n", ninput_items[0], noutput_items);
83 d_msg = d_msgq->delete_head(); // block, waiting for a message
86 d_pending_flag = 1; // new packet, write start of packet flag
88 if((d_msg->length() == 0) && (d_msg->type() == 1)) {
90 return -1; // We're done; no more messages coming.
95 if(output_items.size() == 2)
96 out_flag = (char *) output_items[1];
99 // Build a single symbol:
102 // Initialize all bins to 0 to set unused carriers
103 memset(out, 0, d_fft_length*sizeof(gr_complex));
106 while((d_msg_offset < d_msg->length()) && (i < d_occupied_carriers)) {
107 unsigned char bit = (d_msg->msg()[d_msg_offset] >> (d_bit_offset)) & 0x01;
108 out[i + zeros_on_left] = gr_complex(-1+2*(bit));
111 if(d_bit_offset == 8) {
117 // Ran out of data to put in symbol
118 if (d_msg_offset == d_msg->length()) {
119 while(i < d_occupied_carriers) { // finish filling out the symbol
120 out[i + zeros_on_left] = gr_complex(randombit(),0);
124 if (d_msg->type() == 1) // type == 1 sets EOF
126 d_msg.reset(); // finished packet, free message
127 assert(d_bit_offset == 0);
131 out_flag[0] = d_pending_flag;
134 return 1; // produced symbol