279 lines
7.0 KiB
C
279 lines
7.0 KiB
C
#include <stdint.h>
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#include <errno.h>
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#include <osmocom/core/logging.h>
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#include <osmo-bts/logging.h>
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#include <osmo-bts/amr.h>
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/* Reasonable defaults for AMR-FR and AMR-HR rate configuration.
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* The values are taken from 3GPP TS 51.010-1 (version 13.11.0).
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* See 14.2.19.4.1 and 14.2.20.4.1 for AMR-FR and AMR-HR, respectively.
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*
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* ^ C/I (dB) | FR / HR |
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* | |
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* | |
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* MODE4 | |
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* = | ----+---- THR_MX_Up(3) | 20.5 / 18.0 |
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* | | |
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* | = ----+---- THR_MX_Dn(4) | 18.5 / 16.0 |
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* MODE3 | |
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* | = ----+---- THR_MX_Up(2) | 14.5 / 14.0 |
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* | | |
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* = | ----+---- THR_MX_Dn(3) | 12.5 / 12.0 |
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* MODE2 | |
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* = | ----+---- THR_MX_Up(1) | 8.5 / 10.0 |
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* | | |
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* | = ----+---- THR_MX_Dn(2) | 6.5 / 8.0 |
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* MODE1 | |
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* | |
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* | |
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*/
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static const struct gsm48_multi_rate_conf amr_fr_mr_cfg_def = {
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.m4_75 = 1,
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.m5_90 = 1,
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.m7_95 = 1,
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.m12_2 = 1,
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};
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static const struct amr_mode amr_fr_bts_mode_def[] = {
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{
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.mode = 0, /* 4.75k */
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.threshold = 13, /* THR_MX_Dn(2): 6.5 dB */
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.hysteresis = 4, /* THR_MX_Up(1): 8.5 dB */
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},
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{
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.mode = 2, /* 5.90k */
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.threshold = 25, /* THR_MX_Dn(3): 12.5 dB */
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.hysteresis = 4, /* THR_MX_Up(2): 14.5 dB */
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},
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{
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.mode = 5, /* 7.95k */
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.threshold = 37, /* THR_MX_Dn(4): 18.5 dB */
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.hysteresis = 4, /* THR_MX_Up(3): 20.5 dB */
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},
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{
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.mode = 7, /* 12.2k */
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/* this is the last mode, so no threshold */
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},
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};
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static const struct gsm48_multi_rate_conf amr_hr_mr_cfg_def = {
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.m4_75 = 1,
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.m5_90 = 1,
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.m6_70 = 1,
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.m7_95 = 1,
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};
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static const struct amr_mode amr_hr_bts_mode_def[] = {
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{
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.mode = 0, /* 4.75k */
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.threshold = 16, /* THR_MX_Dn(2): 8.0 dB */
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.hysteresis = 4, /* THR_MX_Up(1): 10.0 dB */
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},
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{
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.mode = 2, /* 5.90k */
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.threshold = 24, /* THR_MX_Dn(3): 12.0 dB */
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.hysteresis = 4, /* THR_MX_Up(2): 14.0 dB */
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},
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{
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.mode = 3, /* 6.70k */
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.threshold = 32, /* THR_MX_Dn(4): 16.0 dB */
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.hysteresis = 4, /* THR_MX_Up(3): 18.0 dB */
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},
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{
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.mode = 5, /* 7.95k */
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/* this is the last mode, so no threshold */
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},
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};
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void amr_log_mr_conf(int ss, int logl, const char *pfx,
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struct amr_multirate_conf *amr_mrc)
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{
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int i;
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LOGP(ss, logl, "%s AMR MR Conf: num_modes=%u",
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pfx, amr_mrc->num_modes);
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for (i = 0; i < amr_mrc->num_modes; i++)
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LOGPC(ss, logl, ", mode[%u] = %u/%u/%u",
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i, amr_mrc->mode[i].mode,
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amr_mrc->mode[i].threshold,
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amr_mrc->mode[i].hysteresis);
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LOGPC(ss, logl, "\n");
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}
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static inline int get_amr_mode_idx(const struct amr_multirate_conf *amr_mrc,
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uint8_t cmi)
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{
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unsigned int i;
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for (i = 0; i < amr_mrc->num_modes; i++) {
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if (amr_mrc->mode[i].mode == cmi)
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return i;
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}
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return -EINVAL;
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}
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static inline uint8_t set_cmr_mode_idx(const struct amr_multirate_conf *amr_mrc,
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uint8_t cmr)
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{
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int rc;
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/* Codec Mode Request is in upper 4 bits of RTP payload header,
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* and we simply copy the CMR into the CMC */
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if (cmr == 0xF) {
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/* FIXME: we need some state about the last codec mode */
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return 0;
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}
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rc = get_amr_mode_idx(amr_mrc, cmr);
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if (rc < 0) {
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/* FIXME: we need some state about the last codec mode */
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LOGP(DRTP, LOGL_INFO, "RTP->L1: overriding CMR %u\n", cmr);
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return 0;
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}
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return rc;
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}
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static inline uint8_t set_cmi_mode_idx(const struct amr_multirate_conf *amr_mrc,
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uint8_t cmi)
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{
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int rc = get_amr_mode_idx(amr_mrc, cmi);
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if (rc < 0) {
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LOGP(DRTP, LOGL_ERROR, "AMR CMI %u not part of AMR MR set\n",
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cmi);
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return 0;
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}
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return rc;
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}
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void amr_set_mode_pref(uint8_t *data, const struct amr_multirate_conf *amr_mrc,
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uint8_t cmi, uint8_t cmr)
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{
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data[0] = set_cmi_mode_idx(amr_mrc, cmi);
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data[1] = set_cmr_mode_idx(amr_mrc, cmr);
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}
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/* parse a GSM 04.08 MultiRate Config IE (10.5.2.21aa) in a more
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* comfortable internal data structure */
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int amr_parse_mr_conf(struct amr_multirate_conf *amr_mrc,
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const uint8_t *mr_conf, unsigned int len)
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{
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uint8_t num_codecs = 0;
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int i, j = 0;
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if (len < 2) {
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LOGP(DRSL, LOGL_ERROR, "AMR Multirate IE is too short (%u)\n", len);
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goto ret_einval;
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}
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if ((mr_conf[0] >> 5) != 1) {
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LOGP(DRSL, LOGL_ERROR, "AMR Multirate Version %u unknown\n", (mr_conf[0] >> 5));
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goto ret_einval;
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}
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/* check number of active codecs */
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for (i = 0; i < 8; i++) {
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if (mr_conf[1] & (1 << i))
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num_codecs++;
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}
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/* check for minimum length */
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if (num_codecs == 0 ||
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(num_codecs == 1 && len < 2) ||
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(num_codecs == 2 && len < 4) ||
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(num_codecs == 3 && len < 5) ||
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(num_codecs == 4 && len < 6) ||
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(num_codecs > 4)) {
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LOGP(DRSL, LOGL_ERROR, "AMR Multirate with %u modes len=%u "
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"not possible\n", num_codecs, len);
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goto ret_einval;
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}
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/* copy the first two octets of the IE */
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amr_mrc->gsm48_ie[0] = mr_conf[0];
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amr_mrc->gsm48_ie[1] = mr_conf[1];
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amr_mrc->num_modes = num_codecs;
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for (i = 0; i < 8; i++) {
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if (mr_conf[1] & (1 << i)) {
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amr_mrc->mode[j++].mode = i;
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}
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}
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/* skip the first two octets of the IE */
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mr_conf += 2;
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if (num_codecs >= 2) {
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amr_mrc->mode[0].threshold = mr_conf[0] & 0x3F;
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amr_mrc->mode[0].hysteresis = mr_conf[1] >> 4;
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}
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if (num_codecs >= 3) {
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amr_mrc->mode[1].threshold =
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((mr_conf[1] & 0xF) << 2) | (mr_conf[2] >> 6);
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amr_mrc->mode[1].hysteresis = (mr_conf[2] >> 2) & 0xF;
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}
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if (num_codecs >= 4) {
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amr_mrc->mode[2].threshold =
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((mr_conf[2] & 0x3) << 4) | (mr_conf[3] >> 4);
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amr_mrc->mode[2].hysteresis = mr_conf[3] & 0xF;
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}
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return num_codecs;
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ret_einval:
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return -EINVAL;
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}
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/*! \brief determine AMR initial codec mode for given logical channel
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* \returns integer between 0..3 for AMR codce mode 1..4 */
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unsigned int amr_get_initial_mode(struct gsm_lchan *lchan)
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{
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struct amr_multirate_conf *amr_mrc = &lchan->tch.amr_mr;
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struct gsm48_multi_rate_conf *mr_conf =
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(struct gsm48_multi_rate_conf *) amr_mrc->gsm48_ie;
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if (mr_conf->icmi) {
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/* initial mode given, coding in TS 05.09 3.4.1 */
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return mr_conf->smod;
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} else {
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/* implicit rule according to TS 05.09 Chapter 3.4.3 */
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switch (amr_mrc->num_modes) {
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case 2:
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case 3:
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/* return the most robust */
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return 0;
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case 4:
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/* return the second-most robust */
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return 1;
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case 1:
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default:
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/* return the only mode we have */
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return 0;
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}
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}
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}
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void amr_init_mr_conf_def(struct gsm_lchan *lchan)
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{
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const struct gsm48_multi_rate_conf *mr_cfg;
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const struct amr_mode *bts_mode;
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unsigned int num_modes;
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if (lchan->type == GSM_LCHAN_TCH_F) {
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num_modes = ARRAY_SIZE(amr_fr_bts_mode_def);
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bts_mode = &amr_fr_bts_mode_def[0];
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mr_cfg = &amr_fr_mr_cfg_def;
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} else {
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num_modes = ARRAY_SIZE(amr_hr_bts_mode_def);
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bts_mode = &amr_hr_bts_mode_def[0];
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mr_cfg = &amr_hr_mr_cfg_def;
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}
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memcpy(lchan->tch.amr_mr.gsm48_ie, mr_cfg,
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sizeof(lchan->tch.amr_mr.gsm48_ie));
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memcpy(&lchan->tch.amr_mr.mode[0], &bts_mode[0],
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sizeof(lchan->tch.amr_mr.mode));
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lchan->tch.amr_mr.num_modes = num_modes;
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}
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