Add TCH/H decoder block with AMR multirate support
Add new TCHH channel mode
Add two new optional arguments
-m CHAN_MODE, --mode=CHAN_MODE
Channel mode. Valid options are 'BCCH' (Non-combined
C0), 'BCCH_SDCCH4'(Combined C0), 'SDCCH8' (Stand-alone
control channel) 'TCHF' (Traffic Channel, Full rate),
'TCHH' (Traffic Channel, Half rate)
--sub-channel=TCH_H_CHANNEL
TCH/H sub-channel. [default=0]
--multi-rate=MULTI_RATE
The MultiRrate configuration element from the
Assigment Command message. Example: 28111a40. See 3GPP
TS 44.018 - 10.5.2.21aa MultiRate configuration
Example:
grgsm_decode -m TCHH --sub-channel 0 --multi-rate 2811 -o voice.amr ...
diff --git a/lib/decoding/tch_h_decoder_impl.cc b/lib/decoding/tch_h_decoder_impl.cc
new file mode 100644
index 0000000..b7672e3
--- /dev/null
+++ b/lib/decoding/tch_h_decoder_impl.cc
@@ -0,0 +1,357 @@
+/* -*- c++ -*- */
+/*
+ * @file
+ * @author (C) 2018 by Vasil Velichkov <vvvelichkov@gmail.com>
+ * @section LICENSE
+ *
+ * Gr-gsm 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.
+ *
+ * Gr-gsm 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 gr-gsm; 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 <grgsm/gsmtap.h>
+#include "tch_h_decoder_impl.h"
+
+extern "C" {
+#include "osmocom/gsm/protocol/gsm_04_08.h"
+#include "osmocom/coding/gsm0503_coding.h"
+}
+
+namespace gr {
+ namespace gsm {
+
+ static int ubits2sbits(ubit_t *ubits, sbit_t *sbits, int count)
+ {
+ int i;
+
+ for (i = 0; i < count; i++) {
+ if (*ubits == 0x23) {
+ ubits++;
+ sbits++;
+ continue;
+ }
+ if ((*ubits++) & 1)
+ *sbits++ = -127;
+ else
+ *sbits++ = 127;
+ }
+
+ return count;
+ }
+
+
+ tch_h_decoder::sptr
+ tch_h_decoder::make(unsigned int sub_channel, std::string multi_rate, bool boundary_check)
+ {
+ return gnuradio::get_initial_sptr
+ (new tch_h_decoder_impl(sub_channel, multi_rate, boundary_check));
+ }
+
+ /*
+ * Constructor
+ */
+ tch_h_decoder_impl::tch_h_decoder_impl(unsigned int sub_channel, std::string multi_rate, bool boundary_check)
+ : gr::block("tch_h_decoder",
+ gr::io_signature::make(0, 0, 0),
+ gr::io_signature::make(0, 0, 0)),
+ d_collected_bursts_num(0),
+ d_tch_mode(TCH_HS),
+ d_sub_channel(sub_channel),
+ d_boundary_check(boundary_check),
+ d_boundary_decode(false),
+ d_header_sent(false),
+ d_ft(0),
+ d_cmr(0)
+ {
+ //setup input/output ports
+ message_port_register_in(pmt::mp("bursts"));
+ set_msg_handler(pmt::mp("bursts"), boost::bind(&tch_h_decoder_impl::decode, this, _1));
+ message_port_register_out(pmt::mp("msgs"));
+ message_port_register_out(pmt::mp("voice"));
+
+ if(multi_rate.length())
+ {
+ std::cout<<"multi_rate configuration: "<<multi_rate<<std::endl;
+ if (multi_rate.length() < 4 || multi_rate.length() % 2)
+ {
+ throw std::invalid_argument("Invalid multi_rate hexstring");
+ }
+
+ std::vector<uint8_t> binary;
+ for (std::string::const_iterator it = multi_rate.begin();
+ it != multi_rate.end(); it += 2)
+ {
+ std::string byte(it, it + 2);
+ char* end = NULL;
+ errno = 0;
+ uint8_t b = strtoul(byte.c_str(), &end, 16);
+ if (errno != 0 || *end != '\0')
+ {
+ throw std::invalid_argument("Invalid multi_rate hexstring");
+ }
+ binary.push_back(b);
+ }
+
+ if (binary.size() < 2) {
+ throw std::invalid_argument("The multi_rate is too short");
+ }
+
+ //GSM A-I/F DTAP - Assignment Command
+ // Protocol Discriminator: Radio Resources Management messages (6)
+ // DTAP Radio Resources Management Message Type: Assignment Command (0x2e)
+ // Channel Description 2 - Description of the First Channel, after time
+ // Power Command
+ // Channel Mode - Mode of the First Channel(Channel Set 1)
+ // MultiRate configuration
+ // Element ID: 0x03
+ // Length: 4
+ // 001. .... = Multirate speech version: Adaptive Multirate speech version 1 (1)
+ // ...0 .... = NSCB: Noise Suppression Control Bit: Noise Suppression can be used (default) (0)
+ // .... 1... = ICMI: Initial Codec Mode Indicator: The initial codec mode is defined by the Start Mode field (1)
+ // .... ..00 = Start Mode: 0
+ // 0... .... = 12,2 kbit/s codec rate: is not part of the subset
+ // .0.. .... = 10,2 kbit/s codec rate: is not part of the subset
+ // ..0. .... = 7,95 kbit/s codec rate: is not part of the subset
+ // ...1 .... = 7,40 kbit/s codec rate: is part of the subset
+ // .... 0... = 6,70 kbit/s codec rate: is not part of the subset
+ // .... .0.. = 5,90 kbit/s codec rate: is not part of the subset
+ // .... ..0. = 5,15 kbit/s codec rate: is not part of the subset
+ // .... ...1 = 4,75 kbit/s codec rate: is part of the subset
+ // ..01 1010 = AMR Threshold: 13.0 dB (26)
+ // 0100 .... = AMR Hysteresis: 2.0 dB (4)
+
+ const uint8_t first = binary[0];
+ uint8_t multirate_speech_ver = (first >> 5) & 0x07;
+ if (multirate_speech_ver == 1)
+ {
+ d_tch_mode = TCH_AFS4_75;
+ }
+ else if (multirate_speech_ver == 2)
+ {
+ throw std::invalid_argument("Adaptive Multirate speech version 2 is not supported");
+ }
+ else
+ {
+ throw std::invalid_argument("Multirate speech version");
+ }
+
+ bool ncsb = (first >> 4) & 0x01;
+ bool icmi = (first >> 3) & 0x01;
+ uint8_t start = first & 0x03;
+
+ const uint8_t codecs = binary[1];
+ for (int i = 0; i < 8; i++)
+ {
+ if ((codecs >> i) & 1)
+ {
+ d_multi_rate_codes.push_back(i);
+ }
+ }
+
+ std::cout<<"Enabled AMR Codecs:"<<std::endl;
+ for(std::vector<uint8_t>::const_iterator it = d_multi_rate_codes.begin();
+ it != d_multi_rate_codes.end();
+ it ++)
+ {
+ switch(*it)
+ {
+ case 0:
+ std::cout<<"4,75 kbit/s codec rate: is part of the subset"<<std::endl;
+ break;
+ case 1:
+ std::cout<<"5,15 kbit/s codec rate: is part of the subset"<<std::endl;
+ break;
+ case 2:
+ std::cout<<"6,90 kbit/s codec rate: is part of the subset"<<std::endl;
+ break;
+ case 3:
+ std::cout<<"6,70 kbit/s codec rate: is part of the subset"<<std::endl;
+ break;
+ case 4:
+ std::cout<<"7,40 kbit/s codec rate: is part of the subset"<<std::endl;
+ break;
+ case 5:
+ std::cout<<"7,95 kbit/s codec rate: is part of the subset"<<std::endl;
+ break;
+ case 6:
+ std::cout<<"12,2 kbit/s codec rate: is part of the subset"<<std::endl;
+ }
+ }
+ if (d_multi_rate_codes.size() > 4) {
+ throw std::invalid_argument("More then 4 multirate codes");
+ }
+ }
+ }
+
+ tch_h_decoder_impl::~tch_h_decoder_impl()
+ {
+ }
+
+ void tch_h_decoder_impl::decode(pmt::pmt_t msg)
+ {
+ d_bursts[d_collected_bursts_num++] = msg;
+ if (d_collected_bursts_num <= 7)
+ {
+ return;
+ }
+
+ gsmtap_hdr* header = (gsmtap_hdr*)(pmt::blob_data(pmt::cdr(msg)));
+ uint32_t frame_nr = be32toh(header->frame_number);
+ bool uplink_burst = (be16toh(header->arfcn) & 0x4000) ? true : false;
+
+ //TODO: Check in 3gpp specs which frames could contains facch/h frames
+ //and replace this ugly formula with table
+ int fn_is_odd = (((frame_nr - (uplink_burst ? 10 : 15)) % 26) >> 2) & 1;
+
+ ubit_t bursts_u[116 * 6] = {0}; //facch/h is 6 bursts
+
+ //reorganize data
+ for (int ii = 0; ii < 8; ii++)
+ {
+ //skip the 4th and 5th bursts
+ if (ii == 4 || ii == 5) continue;
+
+ int8_t* burst_bits = (int8_t*)(pmt::blob_data(pmt::cdr(d_bursts[ii])))+sizeof(gsmtap_hdr);
+
+ //copy 6th and 7th burst to 4th and 5th position
+ int n = ii < 6 ? ii : ii - 2;
+
+ memcpy(&bursts_u[n*116], &burst_bits[3],58);
+ memcpy(&bursts_u[n*116+58], &burst_bits[3+57+1+26],58);
+ }
+
+ //Convert to sbits
+ sbit_t bursts_s[116 * 6] = {0};
+ ubits2sbits(bursts_u, bursts_s, 116 * 6);
+
+ //Prepare burst for the next iteration by shifting them by 4
+ for (int ii = 0; ii < 4; ii++) {
+ d_bursts[ii] = d_bursts[ii + 4];
+ }
+ d_collected_bursts_num = 4;
+
+ uint8_t frameBuffer[64];
+ int frameLength = -1;
+ int n_errors, n_bits_total;
+
+ if (d_tch_mode == TCH_HS)
+ {
+ frameLength = gsm0503_tch_hr_decode(frameBuffer, bursts_s, fn_is_odd, &n_errors, &n_bits_total);
+ }
+ else
+ {
+ frameLength = gsm0503_tch_ahs_decode(frameBuffer, bursts_s, fn_is_odd,
+ fn_is_odd, //int codec_mode_req,
+ &d_multi_rate_codes.front(), d_multi_rate_codes.size(),
+ &d_ft,
+ &d_cmr,
+ &n_errors, &n_bits_total);
+ }
+
+ if (frameLength < 12)
+ {
+ if (!d_boundary_check || d_boundary_decode) {
+ std::cerr<<"Error! frame_nr:"<<frame_nr<<" mod26:"<<frame_nr%26
+ <<" fn_is_odd:"<<fn_is_odd<<" length:"<<frameLength<<std::endl;
+ }
+ return;
+ }
+ else if (frameLength == GSM_MACBLOCK_LEN) //FACCH/H
+ {
+ pmt::pmt_t first_header_plus_burst = pmt::cdr(d_bursts[0]);
+ gsmtap_hdr* header = (gsmtap_hdr *)pmt::blob_data(first_header_plus_burst);
+ int8_t header_plus_data[sizeof(gsmtap_hdr)+frameLength];
+ memcpy(header_plus_data, header, sizeof(gsmtap_hdr));
+ memcpy(header_plus_data+sizeof(gsmtap_hdr), frameBuffer, frameLength);
+ ((gsmtap_hdr*)header_plus_data)->type = GSMTAP_TYPE_UM;
+
+ pmt::pmt_t msg_binary_blob = pmt::make_blob(header_plus_data, frameLength + sizeof(gsmtap_hdr));
+ pmt::pmt_t msg_out = pmt::cons(pmt::PMT_NIL, msg_binary_blob);
+
+ message_port_pub(pmt::mp("msgs"), msg_out);
+
+ // if d_boundary_check is enabled, we set d_boundary_decode to true, when a
+ // "Connect" or "Connect Acknowledge" message is received, and
+ // we set d_boundary_decode back to false, when "Release" message is received
+ if (d_boundary_check)
+ {
+ // check if this is a call control message
+ if ((frameBuffer[3] & 0x0f) == 0x03)
+ {
+ // Connect specified in GSM 04.08, 9.3.5
+ if ((frameBuffer[4] & 0x3f) == 0x07)
+ {
+ d_boundary_decode = true;
+ }
+ // Connect Acknowledge specified in GSM 04.08, 9.3.6
+ else if ((frameBuffer[4] & 0x3f) == 0x0f)
+ {
+ d_boundary_decode = true;
+ }
+ // Release specified in GSM 04.08, 9.3.18
+ else if ((frameBuffer[4] & 0x3f) == 0x2d)
+ {
+ d_boundary_decode = false;
+ }
+ }
+ }
+ return;
+ }
+
+ if (!d_header_sent && d_tch_mode != TCH_HS)
+ {
+ const unsigned char amr_nb_magic[7] = "#!AMR\n";
+ message_port_pub(pmt::mp("voice"), pmt::cons(pmt::PMT_NIL, pmt::make_blob(amr_nb_magic, 6)));
+ d_header_sent = true;
+ }
+
+ if (!n_errors && (!d_boundary_check || d_boundary_decode))
+ {
+ //std::cerr<<"Voice frame_nr:"<<frame_nr<<" mod26:"<<frame_nr%26<<" is_odd:"<<fn_is_odd
+ // <<" type:"<<(uint32_t)d_ft<<" cmr:"<<(uint32_t)d_cmr
+ // <<" errors:"<<n_errors<<std::endl;
+
+ if (d_tch_mode != TCH_HS)
+ {
+ //Move one byte to make space for the header
+ memmove(frameBuffer + 1, frameBuffer, frameLength);
+ //Add the AMR header
+ switch(frameLength)
+ {
+ case 12: frameBuffer[0] = (0 << 3); break; //TCH/AHS4.75
+ case 13: frameBuffer[0] = (1 << 3); break; //TCH/AHS5.15
+ case 15: frameBuffer[0] = (2 << 3); break; //TCH/AHS5.9
+ case 17: frameBuffer[0] = (3 << 3); break; //TCH/AHS6.7
+ case 19: frameBuffer[0] = (4 << 3); break; //TCH/AHS7.4
+ case 20: frameBuffer[0] = (5 << 3); break; //TCH/AHS7.95
+ default: std::cerr<<"Unexpected voice frame length:"<<frameLength<<std::endl; return;
+ }
+ frameLength += 1;
+ }
+
+ //std::ostringstream out;
+ //out << "voice frame: ";
+ //for (int i = 0; i < frameLength; i++)
+ // out << " " << (std::hex) << std::setw(2) << std::setfill('0') << (uint32_t)*(frameBuffer + i);
+ //std::cerr << out.str() << std::endl;
+ message_port_pub(pmt::mp("voice"), pmt::cons(pmt::PMT_NIL, pmt::make_blob(frameBuffer, frameLength)));
+ }
+ }
+ } /* namespace gsm */
+} /* namespace gr */
+