piotr | faacc72 | 2014-07-20 23:48:32 +0200 | [diff] [blame] | 1 | /* -*- c++ -*- */ |
| 2 | /* |
| 3 | * Copyright 2014 <+YOU OR YOUR COMPANY+>. |
| 4 | * |
| 5 | * This is free software; you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License as published by |
| 7 | * the Free Software Foundation; either version 3, or (at your option) |
| 8 | * any later version. |
| 9 | * |
| 10 | * This software is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License |
| 16 | * along with this software; see the file COPYING. If not, write to |
| 17 | * the Free Software Foundation, Inc., 51 Franklin Street, |
| 18 | * Boston, MA 02110-1301, USA. |
| 19 | */ |
| 20 | |
| 21 | #ifdef HAVE_CONFIG_H |
| 22 | #include "config.h" |
| 23 | #endif |
| 24 | |
| 25 | #include <gnuradio/io_signature.h> |
| 26 | #include <gsm/gsmtap.h> |
| 27 | #include "control_channels_decoder_impl.h" |
| 28 | |
ptrkrysik | 617ba03 | 2014-11-21 10:11:05 +0100 | [diff] [blame^] | 29 | #define DATA_BYTES 23 |
| 30 | |
piotr | faacc72 | 2014-07-20 23:48:32 +0200 | [diff] [blame] | 31 | namespace gr { |
| 32 | namespace gsm { |
| 33 | |
| 34 | control_channels_decoder::sptr |
| 35 | control_channels_decoder::make() |
| 36 | { |
| 37 | return gnuradio::get_initial_sptr |
| 38 | (new control_channels_decoder_impl()); |
| 39 | } |
| 40 | |
| 41 | /* |
ptrkrysik | 7f61c64 | 2014-10-30 08:57:27 +0100 | [diff] [blame] | 42 | * Constructor |
piotr | faacc72 | 2014-07-20 23:48:32 +0200 | [diff] [blame] | 43 | */ |
| 44 | control_channels_decoder_impl::control_channels_decoder_impl() |
| 45 | : gr::block("control_channels_decoder", |
| 46 | gr::io_signature::make(0, 0, 0), |
| 47 | gr::io_signature::make(0, 0, 0)), |
| 48 | d_collected_bursts_num(0) |
| 49 | { |
| 50 | //initialize de/interleaver |
| 51 | int j, k, B; |
| 52 | for (k = 0; k < CONV_SIZE; k++) |
| 53 | { |
| 54 | B = k % 4; |
| 55 | j = 2 * ((49 * k) % 57) + ((k % 8) / 4); |
| 56 | interleave_trans[k] = B * 114 + j; //114=57 + 57 |
| 57 | } |
ptrkrysik | 7f61c64 | 2014-10-30 08:57:27 +0100 | [diff] [blame] | 58 | |
| 59 | //initialize decoder |
piotr | faacc72 | 2014-07-20 23:48:32 +0200 | [diff] [blame] | 60 | FC_init(&fc_ctx, 40, 184); |
ptrkrysik | 7f61c64 | 2014-10-30 08:57:27 +0100 | [diff] [blame] | 61 | |
| 62 | //setup input/output ports |
piotr | faacc72 | 2014-07-20 23:48:32 +0200 | [diff] [blame] | 63 | message_port_register_in(pmt::mp("bursts")); |
| 64 | set_msg_handler(pmt::mp("bursts"), boost::bind(&control_channels_decoder_impl::decode, this, _1)); |
piotr | b529a59 | 2014-08-04 11:30:43 +0200 | [diff] [blame] | 65 | message_port_register_out(pmt::mp("msgs")); |
piotr | faacc72 | 2014-07-20 23:48:32 +0200 | [diff] [blame] | 66 | } |
| 67 | |
piotr | faacc72 | 2014-07-20 23:48:32 +0200 | [diff] [blame] | 68 | control_channels_decoder_impl::~control_channels_decoder_impl() |
| 69 | { |
| 70 | } |
| 71 | |
| 72 | void control_channels_decoder_impl::decode(pmt::pmt_t msg) |
| 73 | { |
| 74 | unsigned char iBLOCK[BLOCKS*iBLOCK_SIZE], hl, hn, conv_data[CONV_SIZE], decoded_data[PARITY_OUTPUT_SIZE]; |
| 75 | d_bursts[d_collected_bursts_num] = msg; |
| 76 | d_collected_bursts_num++; |
| 77 | //get convecutive bursts |
piotr | faacc72 | 2014-07-20 23:48:32 +0200 | [diff] [blame] | 78 | |
| 79 | if(d_collected_bursts_num==4) |
| 80 | { |
| 81 | d_collected_bursts_num=0; |
| 82 | //reorganize data |
| 83 | for(int ii = 0; ii < 4; ii++) |
| 84 | { |
ptrkrysik | 617ba03 | 2014-11-21 10:11:05 +0100 | [diff] [blame^] | 85 | pmt::pmt_t header_plus_burst = pmt::cdr(d_bursts[ii]); |
| 86 | int8_t * burst_bits = (int8_t *)(pmt::blob_data(header_plus_burst))+sizeof(gsmtap_hdr); |
piotr | faacc72 | 2014-07-20 23:48:32 +0200 | [diff] [blame] | 87 | |
| 88 | for(int jj = 0; jj < 57; jj++) |
| 89 | { |
| 90 | iBLOCK[ii*iBLOCK_SIZE+jj] = burst_bits[jj + 3]; |
| 91 | iBLOCK[ii*iBLOCK_SIZE+jj+57] = burst_bits[jj + 88]; //88 = 3+57+1+26+1 |
| 92 | } |
| 93 | } |
| 94 | //deinterleave |
| 95 | for (int k = 0; k < CONV_SIZE; k++) |
| 96 | { |
| 97 | conv_data[k] = iBLOCK[interleave_trans[k]]; |
| 98 | } |
| 99 | //convolutional code decode |
| 100 | int errors = conv_decode(decoded_data, conv_data); |
| 101 | //std::cout << "Errors:" << errors << " " << parity_check(decoded_data) << std::endl; |
| 102 | // check parity |
| 103 | // If parity check error detected try to fix it. |
| 104 | |
| 105 | if (parity_check(decoded_data)) |
| 106 | { |
| 107 | FC_init(&fc_ctx, 40, 184); |
| 108 | unsigned char crc_result[PARITY_OUTPUT_SIZE]; |
| 109 | if (FC_check_crc(&fc_ctx, decoded_data, crc_result) == 0) |
| 110 | { |
| 111 | //("error: sacch: parity error (errors=%d fn=%d)\n", errors, ctx->fn); |
piotr | ab663c8 | 2014-08-06 14:14:15 +0200 | [diff] [blame] | 112 | //std::cout << "Uncorrectable errors!" << std::endl; |
piotr | faacc72 | 2014-07-20 23:48:32 +0200 | [diff] [blame] | 113 | errors = -1; |
ptrkrysik | 18df2f3 | 2014-11-19 11:33:08 +0100 | [diff] [blame] | 114 | return; |
piotr | faacc72 | 2014-07-20 23:48:32 +0200 | [diff] [blame] | 115 | } else { |
| 116 | //DEBUGF("Successfully corrected parity bits! (errors=%d fn=%d)\n", errors, ctx->fn); |
| 117 | //std::cout << "Corrected some errors" << std::endl; |
| 118 | memcpy(decoded_data, crc_result, PARITY_OUTPUT_SIZE); |
| 119 | errors = 0; |
| 120 | } |
| 121 | } else { |
| 122 | //std::cout << "Everything correct" << std::endl; |
| 123 | } |
| 124 | //compress bits |
| 125 | unsigned char outmsg[27]; |
| 126 | unsigned char sbuf_len=224; |
| 127 | int i, j, c, pos=0; |
| 128 | for(i = 0; i < sbuf_len; i += 8) { |
piotr | ab663c8 | 2014-08-06 14:14:15 +0200 | [diff] [blame] | 129 | for(j = 0, c = 0; (j < 8) && (i + j < sbuf_len); j++){ |
| 130 | c |= (!!decoded_data[i + j]) << j; |
| 131 | } |
| 132 | outmsg[pos++] = c & 0xff; |
| 133 | } |
piotr | b529a59 | 2014-08-04 11:30:43 +0200 | [diff] [blame] | 134 | |
| 135 | //send message with header of the first burst |
ptrkrysik | 617ba03 | 2014-11-21 10:11:05 +0100 | [diff] [blame^] | 136 | pmt::pmt_t first_header_plus_burst = pmt::cdr(d_bursts[0]); |
| 137 | gsmtap_hdr * header = (gsmtap_hdr *)pmt::blob_data(first_header_plus_burst); |
ptrkrysik | 7f61c64 | 2014-10-30 08:57:27 +0100 | [diff] [blame] | 138 | header->type = GSMTAP_TYPE_UM; |
ptrkrysik | 7f61c64 | 2014-10-30 08:57:27 +0100 | [diff] [blame] | 139 | |
ptrkrysik | 617ba03 | 2014-11-21 10:11:05 +0100 | [diff] [blame^] | 140 | int8_t * header_content = (int8_t *)header; |
| 141 | |
| 142 | int8_t header_plus_data[sizeof(gsmtap_hdr)+DATA_BYTES]; |
| 143 | memcpy(header_plus_data, header_content, sizeof(gsmtap_hdr)); |
| 144 | memcpy(header_plus_data+sizeof(gsmtap_hdr), outmsg, DATA_BYTES); |
| 145 | |
| 146 | pmt::pmt_t msg_binary_blob = pmt::make_blob(header_plus_data,DATA_BYTES+sizeof(gsmtap_hdr)); |
ptrkrysik | 7f61c64 | 2014-10-30 08:57:27 +0100 | [diff] [blame] | 147 | pmt::pmt_t msg_out = pmt::cons(pmt::PMT_NIL, msg_binary_blob); |
| 148 | |
piotr | b529a59 | 2014-08-04 11:30:43 +0200 | [diff] [blame] | 149 | message_port_pub(pmt::mp("msgs"), msg_out); |
piotr | faacc72 | 2014-07-20 23:48:32 +0200 | [diff] [blame] | 150 | } |
| 151 | return; |
| 152 | } |
| 153 | } /* namespace gsm */ |
| 154 | } /* namespace gr */ |
| 155 | |