TRX: Support for AMR half speech

7 files changed, 748 insertions, 0 deletions

diff --git a/src/osmo-bts-trx/gsm0503_coding.c b/src/osmo-bts-trx/gsm0503_coding.c
index 490d0f66..c3ce9e57 100644
--- a/src/osmo-bts-trx/gsm0503_coding.c
+++ b/src/osmo-bts-trx/gsm0503_coding.c
@@ -1227,6 +1227,375 @@ facch:
 	return 0;
 }
 
+int tch_ahs_decode(uint8_t *tch_data, sbit_t *bursts, int odd,
+	int codec_mode_req, uint8_t *codec, int codecs, uint8_t *ft,
+	uint8_t *cmr, float *ber)
+{
+	sbit_t iB[912], cB[456], h;
+	ubit_t test[456], d[244], p[6], conv[135];
+	int i, j, k, best = 0, rv, len, steal = 0, id = 0;
+
+	/* only unmap the stealing bits */
+	if (!odd) {
+		for (i=0; i<4; i++) {
+			gsm0503_tch_burst_unmap(NULL, &bursts[i * 116], &h, 0);
+			steal -= h;
+		}
+		for (i=2; i<5; i++) {
+			gsm0503_tch_burst_unmap(NULL, &bursts[i * 116], &h, 1);
+			steal -= h;
+		}
+	}
+
+	/* if we found a stole FACCH, but only at correct alignment */
+	if (steal > 0) {
+		for (i=0; i<6; i++)
+			gsm0503_tch_burst_unmap(&iB[i * 114], &bursts[i * 116],
+				NULL, i>>2);
+		for (i=2; i<4; i++)
+			gsm0503_tch_burst_unmap(&iB[i * 114 + 456],
+				&bursts[i * 116], NULL, 1);
+
+		gsm0503_tch_fr_deinterleave(cB, iB);
+
+		rv = _xcch_decode_cB(tch_data, cB);
+		if (rv)
+			return -1;
+
+		return 23;
+	}
+
+	for (i=0; i<4; i++)
+		gsm0503_tch_burst_unmap(&iB[i * 114], &bursts[i * 116], NULL,
+			i>>1);
+
+	gsm0503_tch_hr_deinterleave(cB, iB);
+
+	for (i=0; i<4; i++) {
+		for (j=0, k=0; j<4; j++)
+			k += abs(((int)gsm0503_ahs_ic_sbit[i][j]) -
+							((int)cB[j]));
+		if (i == 0 || k < best) {
+			best = k;
+			id = i;
+		}
+	}
+
+	/* check if indicated codec fits into range of codecs */
+	if (id >= codecs) {
+		/* codec mode out of range, return id */
+		return id;
+	}
+
+	switch ((codec_mode_req) ? codec[*ft] : codec[id]) {
+	case 5: /* TCH/AHS7.95 */
+		osmo_conv_decode(&gsm0503_conv_tch_ahs_7_95, cB+4, conv);
+
+		tch_amr_unmerge(d, p, conv, 123, 67);
+
+		rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 67, p);
+		if (rv)
+			return -1;
+
+		for (i=0; i<36;i++)
+			d[i+123] = (cB[i+192] < 0) ? 1:0;
+
+		tch_amr_reassemble(tch_data, d, 159);
+
+		len = 20;
+
+		if (ber) {
+			osmo_conv_encode(&gsm0503_conv_tch_ahs_7_95, conv,
+				test+4);
+			*ber = amr_calc_ber(cB+4, test+4, 188);
+		}
+
+		break;
+	case 4: /* TCH/AHS7.4 */
+		osmo_conv_decode(&gsm0503_conv_tch_ahs_7_4, cB+4, conv);
+
+		tch_amr_unmerge(d, p, conv, 120, 61);
+
+		rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 61, p);
+		if (rv)
+			return -1;
+
+		for (i=0; i<28;i++)
+			d[i+120] = (cB[i+200] < 0) ? 1:0;
+
+		tch_amr_reassemble(tch_data, d, 148);
+
+		len = 19;
+
+		if (ber) {
+			osmo_conv_encode(&gsm0503_conv_tch_ahs_7_4, conv,
+				test+4);
+			*ber = amr_calc_ber(cB+4, test+4, 196);
+		}
+
+		break;
+	case 3: /* TCH/AHS6.7 */
+		osmo_conv_decode(&gsm0503_conv_tch_ahs_6_7, cB+4, conv);
+
+		tch_amr_unmerge(d, p, conv, 110, 55);
+
+		rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 55, p);
+		if (rv)
+			return -1;
+
+		for (i=0; i<24;i++)
+			d[i+110] = (cB[i+204] < 0) ? 1:0;
+
+		tch_amr_reassemble(tch_data, d, 134);
+
+		len = 17;
+
+		if (ber) {
+			osmo_conv_encode(&gsm0503_conv_tch_ahs_6_7, conv,
+				test+4);
+			*ber = amr_calc_ber(cB+4, test+4, 200);
+		}
+
+		break;
+	case 2: /* TCH/AHS5.9 */
+		osmo_conv_decode(&gsm0503_conv_tch_ahs_5_9, cB+4, conv);
+
+		tch_amr_unmerge(d, p, conv, 102, 55);
+
+		rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 55, p);
+		if (rv)
+			return -1;
+
+		for (i=0; i<16;i++)
+			d[i+102] = (cB[i+212] < 0) ? 1:0;
+
+		tch_amr_reassemble(tch_data, d, 118);
+
+		len = 15;
+
+		if (ber) {
+			osmo_conv_encode(&gsm0503_conv_tch_ahs_5_9, conv,
+				test+4);
+			*ber = amr_calc_ber(cB+4, test+4, 208);
+		}
+
+		break;
+	case 1: /* TCH/AHS5.15 */
+		osmo_conv_decode(&gsm0503_conv_tch_ahs_5_15, cB+4, conv);
+
+		tch_amr_unmerge(d, p, conv, 91, 49);
+
+		rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 49, p);
+		if (rv)
+			return -1;
+
+		for (i=0; i<12;i++)
+			d[i+91] = (cB[i+216] < 0) ? 1:0;
+
+		tch_amr_reassemble(tch_data, d, 103);
+
+		len = 13;
+
+		if (ber) {
+			osmo_conv_encode(&gsm0503_conv_tch_ahs_5_15, conv,
+				test+4);
+			*ber = amr_calc_ber(cB+4, test+4, 212);
+		}
+
+		break;
+	case 0: /* TCH/AHS4.75 */
+		osmo_conv_decode(&gsm0503_conv_tch_ahs_4_75, cB+4, conv);
+
+		tch_amr_unmerge(d, p, conv, 83, 39);
+
+		rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 39, p);
+		if (rv)
+			return -1;
+
+		for (i=0; i<12;i++)
+			d[i+83] = (cB[i+216] < 0) ? 1:0;
+
+		tch_amr_reassemble(tch_data, d, 95);
+
+		len = 12;
+
+		if (ber) {
+			osmo_conv_encode(&gsm0503_conv_tch_ahs_4_75, conv,
+				test+4);
+			*ber = amr_calc_ber(cB+4, test+4, 212);
+		}
+
+		break;
+	default:
+		fprintf(stderr, "FIXME: FT %d not supported!\n", *ft);
+
+		return -1;
+	}
+
+	/* change codec request / indication, if frame is valid */
+	if (codec_mode_req)
+		*cmr = id;
+	else
+		*ft = id;
+
+	return len;
+}
+
+int tch_ahs_encode(ubit_t *bursts, uint8_t *tch_data, int len,
+	int codec_mode_req, uint8_t *codec, int codecs, uint8_t ft,
+	uint8_t cmr)
+{
+	ubit_t iB[912], cB[456], h;
+	ubit_t d[244], p[6], conv[135];
+	int i;
+	uint8_t id;
+
+	if (len == 23) { /* FACCH */
+		_xcch_encode_cB(cB, tch_data);
+
+		h = 1;
+
+		gsm0503_tch_fr_interleave(cB, iB);
+
+		for (i=0; i<6; i++)
+			gsm0503_tch_burst_map(&iB[i * 114], &bursts[i * 116],
+				&h, i>>2);
+		for (i=2; i<4; i++)
+			gsm0503_tch_burst_map(&iB[i * 114 + 456],
+				&bursts[i * 116], &h, 1);
+
+		return 0;
+	}
+
+	h = 0;
+
+	if (codec_mode_req) {
+		if (cmr >= codecs) {
+			fprintf(stderr, "FIXME: CMR ID %d not in codec list!\n",
+				cmr);
+			return -1;
+		}
+		id = cmr;
+	} else {
+		if (ft >= codecs) {
+			fprintf(stderr, "FIXME: FT ID %d not in codec list!\n",
+				ft);
+			return -1;
+		}
+		id = ft;
+	}
+
+	switch (codec[ft]) {
+	case 5: /* TCH/AHS7.95 */
+		if (len != 20) {
+invalid_length:
+			fprintf(stderr, "FIXME: payload length %d does not "
+				"comply with codec type %d!\n", len, ft);
+			return -1;
+		}
+
+		tch_amr_disassemble(d, tch_data, 159);
+
+		osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 67, p);
+
+		tch_amr_merge(conv, d, p, 123, 67);
+
+		osmo_conv_encode(&gsm0503_conv_tch_ahs_7_95, conv, cB+4);
+
+		memcpy(cB+192, d+123, 36);
+
+		break;
+	case 4: /* TCH/AHS7.4 */
+		if (len != 19)
+			goto invalid_length;
+
+		tch_amr_disassemble(d, tch_data, 148);
+
+		osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 61, p);
+
+		tch_amr_merge(conv, d, p, 120, 61);
+
+		osmo_conv_encode(&gsm0503_conv_tch_ahs_7_4, conv, cB+4);
+
+		memcpy(cB+200, d+120, 28);
+
+		break;
+	case 3: /* TCH/AHS6.7 */
+		if (len != 17)
+			goto invalid_length;
+
+		tch_amr_disassemble(d, tch_data, 134);
+
+		osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 55, p);
+
+		tch_amr_merge(conv, d, p, 110, 55);
+
+		osmo_conv_encode(&gsm0503_conv_tch_ahs_6_7, conv, cB+4);
+
+		memcpy(cB+204, d+110, 24);
+
+		break;
+	case 2: /* TCH/AHS5.9 */
+		if (len != 15)
+			goto invalid_length;
+
+		tch_amr_disassemble(d, tch_data, 118);
+
+		osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 55, p);
+
+		tch_amr_merge(conv, d, p, 102, 55);
+
+		osmo_conv_encode(&gsm0503_conv_tch_ahs_5_9, conv, cB+4);
+
+		memcpy(cB+212, d+102, 16);
+
+		break;
+	case 1: /* TCH/AHS5.15 */
+		if (len != 13)
+			goto invalid_length;
+
+		tch_amr_disassemble(d, tch_data, 103);
+
+		osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 49, p);
+
+		tch_amr_merge(conv, d, p, 91, 49);
+
+		osmo_conv_encode(&gsm0503_conv_tch_ahs_5_15, conv, cB+4);
+
+		memcpy(cB+216, d+91, 12);
+
+		break;
+	case 0: /* TCH/AHS4.75 */
+		if (len != 12)
+			goto invalid_length;
+
+		tch_amr_disassemble(d, tch_data, 95);
+
+		osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 39, p);
+
+		tch_amr_merge(conv, d, p, 83, 39);
+
+		osmo_conv_encode(&gsm0503_conv_tch_ahs_4_75, conv, cB+4);
+
+		memcpy(cB+216, d+83, 12);
+
+		break;
+	default:
+		fprintf(stderr, "FIXME: FT %d not supported!\n", ft);
+
+		return -1;
+	}
+
+	memcpy(cB, gsm0503_afs_ic_ubit[id], 4);
+
+	gsm0503_tch_hr_interleave(cB, iB);
+
+	for (i=0; i<4; i++)
+		gsm0503_tch_burst_map(&iB[i * 114], &bursts[i * 116], &h, i>>1);
+
+	return 0;
+}
+
 /*
  * GSM RACH transcoding
  */
diff --git a/src/osmo-bts-trx/gsm0503_coding.h b/src/osmo-bts-trx/gsm0503_coding.h
index 6bc7dd0e..33b58d3b 100644
--- a/src/osmo-bts-trx/gsm0503_coding.h
+++ b/src/osmo-bts-trx/gsm0503_coding.h
@@ -14,6 +14,12 @@ int tch_afs_decode(uint8_t *tch_data, sbit_t *bursts, int codec_mode_req,
 int tch_afs_encode(ubit_t *bursts, uint8_t *tch_data, int len,
 	int codec_mode_req, uint8_t *codec, int codecs, uint8_t ft,
 	uint8_t cmr);
+int tch_ahs_decode(uint8_t *tch_data, sbit_t *bursts, int odd,
+	int codec_mode_req, uint8_t *codec, int codecs, uint8_t *ft, 
+	uint8_t *cmr, float *ber);
+int tch_ahs_encode(ubit_t *bursts, uint8_t *tch_data, int len,
+	int codec_mode_req, uint8_t *codec, int codecs, uint8_t ft,
+	uint8_t cmr);
 int rach_decode(uint8_t *ra, sbit_t *burst, uint8_t bsic);
 int rach_encode(ubit_t *burst, uint8_t *ra, uint8_t bsic);
 int sch_decode(uint8_t *sb_info, sbit_t *burst);
diff --git a/src/osmo-bts-trx/gsm0503_conv.c b/src/osmo-bts-trx/gsm0503_conv.c
index 71738969..2a814ca3 100644
--- a/src/osmo-bts-trx/gsm0503_conv.c
+++ b/src/osmo-bts-trx/gsm0503_conv.c
@@ -639,3 +639,312 @@ const struct osmo_conv_code gsm0503_conv_tch_afs_4_75 = {
 };
 
 
+/* TCH/AHS7.95 */
+/* ----------- */
+
+static const uint8_t conv_tch_ahs_7_95_next_output[][2] = {
+	{ 0, 3 }, { 1, 2 }, { 0, 3 }, { 1, 2 },
+	{ 0, 3 }, { 1, 2 }, { 0, 3 }, { 1, 2 },
+	{ 0, 3 }, { 1, 2 }, { 0, 3 }, { 1, 2 },
+	{ 0, 3 }, { 1, 2 }, { 0, 3 }, { 1, 2 },
+};
+
+static const uint8_t conv_tch_ahs_7_95_next_state[][2] = {
+	{  0,  1 }, {  2,  3 }, {  4,  5 }, {  6,  7 },
+	{  9,  8 }, { 11, 10 }, { 13, 12 }, { 15, 14 },
+	{  1,  0 }, {  3,  2 }, {  5,  4 }, {  7,  6 },
+	{  8,  9 }, { 10, 11 }, { 12, 13 }, { 14, 15 },
+};
+
+static const uint8_t conv_tch_ahs_7_95_next_term_output[] = {
+	 0,  1,  0,  1,  3,  2,  3,  2,  3,  2,  3,  2,  0,  1,  0,  1,
+};
+
+static const uint8_t conv_tch_ahs_7_95_next_term_state[] = {
+	 0,  2,  4,  6,  8, 10, 12, 14,  0,  2,  4,  6,  8, 10, 12, 14,
+};
+
+static int conv_tch_ahs_7_95_puncture[] = {
+	  1,   3,   5,   7,  11,  15,  19,  23,  27,  31,  35,  43,
+	 47,  51,  55,  59,  63,  67,  71,  79,  83,  87,  91,  95,
+	 99, 103, 107, 115, 119, 123, 127, 131, 135, 139, 143, 151,
+	155, 159, 163, 167, 171, 175, 177, 179, 183, 185, 187, 191,
+	193, 195, 197, 199, 203, 205, 207, 211, 213, 215, 219, 221,
+	223, 227, 229, 231, 233, 235, 239, 241, 243, 247, 249, 251,
+	255, 257, 259, 261, 263, 265,
+	-1, /* end */
+};
+
+const struct osmo_conv_code gsm0503_conv_tch_ahs_7_95 = {
+	.N = 2,
+	.K = 5,
+	.len = 129,
+	.next_output      = conv_tch_ahs_7_95_next_output,
+	.next_state       = conv_tch_ahs_7_95_next_state,
+	.next_term_output = conv_tch_ahs_7_95_next_term_output,
+	.next_term_state  = conv_tch_ahs_7_95_next_term_state,
+	.puncture         = conv_tch_ahs_7_95_puncture,
+};
+
+
+/* TCH/AHS7.4 */
+/* ---------- */
+
+static const uint8_t conv_tch_ahs_7_4_next_output[][2] = {
+	{ 0, 3 }, { 1, 2 }, { 0, 3 }, { 1, 2 },
+	{ 0, 3 }, { 1, 2 }, { 0, 3 }, { 1, 2 },
+	{ 0, 3 }, { 1, 2 }, { 0, 3 }, { 1, 2 },
+	{ 0, 3 }, { 1, 2 }, { 0, 3 }, { 1, 2 },
+};
+
+static const uint8_t conv_tch_ahs_7_4_next_state[][2] = {
+	{  0,  1 }, {  2,  3 }, {  4,  5 }, {  6,  7 },
+	{  9,  8 }, { 11, 10 }, { 13, 12 }, { 15, 14 },
+	{  1,  0 }, {  3,  2 }, {  5,  4 }, {  7,  6 },
+	{  8,  9 }, { 10, 11 }, { 12, 13 }, { 14, 15 },
+};
+
+static const uint8_t conv_tch_ahs_7_4_next_term_output[] = {
+	 0,  1,  0,  1,  3,  2,  3,  2,  3,  2,  3,  2,  0,  1,  0,  1,
+};
+
+static const uint8_t conv_tch_ahs_7_4_next_term_state[] = {
+	 0,  2,  4,  6,  8, 10, 12, 14,  0,  2,  4,  6,  8, 10, 12, 14,
+};
+
+static int conv_tch_ahs_7_4_puncture[] = {
+	  1,   3,   7,  11,  19,  23,  27,  35,  39,  43,  51,  55,
+	 59,  67,  71,  75,  83,  87,  91,  99, 103, 107, 115, 119,
+	123, 131, 135, 139, 143, 147, 151, 155, 159, 163, 167, 171,
+	175, 179, 183, 187, 191, 195, 199, 203, 207, 211, 215, 219,
+	221, 223, 227, 229, 231, 235, 237, 239, 243, 245, 247, 251,
+	253, 255, 257, 259,
+	-1, /* end */
+};
+
+const struct osmo_conv_code gsm0503_conv_tch_ahs_7_4 = {
+	.N = 2,
+	.K = 5,
+	.len = 126,
+	.next_output      = conv_tch_ahs_7_4_next_output,
+	.next_state       = conv_tch_ahs_7_4_next_state,
+	.next_term_output = conv_tch_ahs_7_4_next_term_output,
+	.next_term_state  = conv_tch_ahs_7_4_next_term_state,
+	.puncture         = conv_tch_ahs_7_4_puncture,
+};
+
+
+/* TCH/AHS6.7 */
+/* ---------- */
+
+static const uint8_t conv_tch_ahs_6_7_next_output[][2] = {
+	{ 0, 3 }, { 1, 2 }, { 0, 3 }, { 1, 2 },
+	{ 0, 3 }, { 1, 2 }, { 0, 3 }, { 1, 2 },
+	{ 0, 3 }, { 1, 2 }, { 0, 3 }, { 1, 2 },
+	{ 0, 3 }, { 1, 2 }, { 0, 3 }, { 1, 2 },
+};
+
+static const uint8_t conv_tch_ahs_6_7_next_state[][2] = {
+	{  0,  1 }, {  2,  3 }, {  4,  5 }, {  6,  7 },
+	{  9,  8 }, { 11, 10 }, { 13, 12 }, { 15, 14 },
+	{  1,  0 }, {  3,  2 }, {  5,  4 }, {  7,  6 },
+	{  8,  9 }, { 10, 11 }, { 12, 13 }, { 14, 15 },
+};
+
+static const uint8_t conv_tch_ahs_6_7_next_term_output[] = {
+	 0,  1,  0,  1,  3,  2,  3,  2,  3,  2,  3,  2,  0,  1,  0,  1,
+};
+
+static const uint8_t conv_tch_ahs_6_7_next_term_state[] = {
+	 0,  2,  4,  6,  8, 10, 12, 14,  0,  2,  4,  6,  8, 10, 12, 14,
+};
+
+static int conv_tch_ahs_6_7_puncture[] = {
+	  1,   3,   9,  19,  29,  39,  49,  59,  69,  79,  89,  99,
+	109, 119, 129, 139, 149, 159, 167, 169, 177, 179, 187, 189,
+	197, 199, 203, 207, 209, 213, 217, 219, 223, 227, 229, 231,
+	233, 235, 237, 239,
+	-1, /* end */
+};
+
+const struct osmo_conv_code gsm0503_conv_tch_ahs_6_7 = {
+	.N = 2,
+	.K = 5,
+	.len = 116,
+	.next_output      = conv_tch_ahs_6_7_next_output,
+	.next_state       = conv_tch_ahs_6_7_next_state,
+	.next_term_output = conv_tch_ahs_6_7_next_term_output,
+	.next_term_state  = conv_tch_ahs_6_7_next_term_state,
+	.puncture         = conv_tch_ahs_6_7_puncture,
+};
+
+
+/* TCH/AHS5.9 */
+/* ---------- */
+
+static const uint8_t conv_tch_ahs_5_9_next_output[][2] = {
+	{ 0, 3 }, { 1, 2 }, { 0, 3 }, { 1, 2 },
+	{ 0, 3 }, { 1, 2 }, { 0, 3 }, { 1, 2 },
+	{ 0, 3 }, { 1, 2 }, { 0, 3 }, { 1, 2 },
+	{ 0, 3 }, { 1, 2 }, { 0, 3 }, { 1, 2 },
+};
+
+static const uint8_t conv_tch_ahs_5_9_next_state[][2] = {
+	{  0,  1 }, {  2,  3 }, {  4,  5 }, {  6,  7 },
+	{  9,  8 }, { 11, 10 }, { 13, 12 }, { 15, 14 },
+	{  1,  0 }, {  3,  2 }, {  5,  4 }, {  7,  6 },
+	{  8,  9 }, { 10, 11 }, { 12, 13 }, { 14, 15 },
+};
+
+static const uint8_t conv_tch_ahs_5_9_next_term_output[] = {
+	 0,  1,  0,  1,  3,  2,  3,  2,  3,  2,  3,  2,  0,  1,  0,  1,
+};
+
+static const uint8_t conv_tch_ahs_5_9_next_term_state[] = {
+	 0,  2,  4,  6,  8, 10, 12, 14,  0,  2,  4,  6,  8, 10, 12, 14,
+};
+
+static int conv_tch_ahs_5_9_puncture[] = {
+	  1,  15,  71, 127, 139, 151, 163, 175, 187, 195, 203, 211,
+	215, 219, 221, 223,
+	-1, /* end */
+};
+
+const struct osmo_conv_code gsm0503_conv_tch_ahs_5_9 = {
+	.N = 2,
+	.K = 5,
+	.len = 108,
+	.next_output      = conv_tch_ahs_5_9_next_output,
+	.next_state       = conv_tch_ahs_5_9_next_state,
+	.next_term_output = conv_tch_ahs_5_9_next_term_output,
+	.next_term_state  = conv_tch_ahs_5_9_next_term_state,
+	.puncture         = conv_tch_ahs_5_9_puncture,
+};
+
+
+/* TCH/AHS5.15 */
+/* ----------- */
+
+static const uint8_t conv_tch_ahs_5_15_next_output[][2] = {
+	{ 0, 7 }, { 2, 5 }, { 4, 3 }, { 6, 1 },
+	{ 2, 5 }, { 0, 7 }, { 6, 1 }, { 4, 3 },
+	{ 0, 7 }, { 2, 5 }, { 4, 3 }, { 6, 1 },
+	{ 2, 5 }, { 0, 7 }, { 6, 1 }, { 4, 3 },
+};
+
+static const uint8_t conv_tch_ahs_5_15_next_state[][2] = {
+	{  0,  1 }, {  3,  2 }, {  5,  4 }, {  6,  7 },
+	{  9,  8 }, { 10, 11 }, { 12, 13 }, { 15, 14 },
+	{  1,  0 }, {  2,  3 }, {  4,  5 }, {  7,  6 },
+	{  8,  9 }, { 11, 10 }, { 13, 12 }, { 14, 15 },
+};
+
+static const uint8_t conv_tch_ahs_5_15_next_term_output[] = {
+	 0,  5,  3,  6,  5,  0,  6,  3,  7,  2,  4,  1,  2,  7,  1,  4,
+};
+
+static const uint8_t conv_tch_ahs_5_15_next_term_state[] = {
+	 0,  2,  4,  6,  8, 10, 12, 14,  0,  2,  4,  6,  8, 10, 12, 14,
+};
+
+static int conv_tch_ahs_5_15_puncture[] = {
+	  0,   1,   3,   4,   6,   9,  12,  15,  18,  21,  27,  33,
+	 39,  45,  51,  54, 57,  63,  69,  75,  81,  87,  90,  93,
+	 99, 105, 111, 117, 123, 126, 129, 135, 141, 147, 153, 159,
+	162, 165, 168, 171, 174, 177, 180, 183, 186, 189, 192, 195,
+	198, 201, 204, 207, 210, 213, 216, 219, 222, 225, 228, 231,
+	234, 237, 240, 243, 244, 246, 249, 252, 255, 256, 258, 261,
+	264, 267, 268, 270, 273, 276, 279, 280, 282, 285, 288, 289,
+	291, 294, 295, 297, 298, 300, 301,
+	-1, /* end */
+};
+
+const struct osmo_conv_code gsm0503_conv_tch_ahs_5_15 = {
+	.N = 3,
+	.K = 5,
+	.len = 97,
+	.next_output      = conv_tch_ahs_5_15_next_output,
+	.next_state       = conv_tch_ahs_5_15_next_state,
+	.next_term_output = conv_tch_ahs_5_15_next_term_output,
+	.next_term_state  = conv_tch_ahs_5_15_next_term_state,
+	.puncture         = conv_tch_ahs_5_15_puncture,
+};
+
+
+/* TCH/AHS4.75 */
+/* ----------- */
+
+static const uint8_t conv_tch_ahs_4_75_next_output[][2] = {
+	{ 0, 7 }, { 3, 4 }, { 2, 5 }, { 1, 6 },
+	{ 2, 5 }, { 1, 6 }, { 0, 7 }, { 3, 4 },
+	{ 3, 4 }, { 0, 7 }, { 1, 6 }, { 2, 5 },
+	{ 1, 6 }, { 2, 5 }, { 3, 4 }, { 0, 7 },
+	{ 3, 4 }, { 0, 7 }, { 1, 6 }, { 2, 5 },
+	{ 1, 6 }, { 2, 5 }, { 3, 4 }, { 0, 7 },
+	{ 0, 7 }, { 3, 4 }, { 2, 5 }, { 1, 6 },
+	{ 2, 5 }, { 1, 6 }, { 0, 7 }, { 3, 4 },
+	{ 0, 7 }, { 3, 4 }, { 2, 5 }, { 1, 6 },
+	{ 2, 5 }, { 1, 6 }, { 0, 7 }, { 3, 4 },
+	{ 3, 4 }, { 0, 7 }, { 1, 6 }, { 2, 5 },
+	{ 1, 6 }, { 2, 5 }, { 3, 4 }, { 0, 7 },
+	{ 3, 4 }, { 0, 7 }, { 1, 6 }, { 2, 5 },
+	{ 1, 6 }, { 2, 5 }, { 3, 4 }, { 0, 7 },
+	{ 0, 7 }, { 3, 4 }, { 2, 5 }, { 1, 6 },
+	{ 2, 5 }, { 1, 6 }, { 0, 7 }, { 3, 4 },
+};
+
+static const uint8_t conv_tch_ahs_4_75_next_state[][2] = {
+	{  0,  1 }, {  2,  3 }, {  5,  4 }, {  7,  6 },
+	{  9,  8 }, { 11, 10 }, { 12, 13 }, { 14, 15 },
+	{ 16, 17 }, { 18, 19 }, { 21, 20 }, { 23, 22 },
+	{ 25, 24 }, { 27, 26 }, { 28, 29 }, { 30, 31 },
+	{ 33, 32 }, { 35, 34 }, { 36, 37 }, { 38, 39 },
+	{ 40, 41 }, { 42, 43 }, { 45, 44 }, { 47, 46 },
+	{ 49, 48 }, { 51, 50 }, { 52, 53 }, { 54, 55 },
+	{ 56, 57 }, { 58, 59 }, { 61, 60 }, { 63, 62 },
+	{  1,  0 }, {  3,  2 }, {  4,  5 }, {  6,  7 },
+	{  8,  9 }, { 10, 11 }, { 13, 12 }, { 15, 14 },
+	{ 17, 16 }, { 19, 18 }, { 20, 21 }, { 22, 23 },
+	{ 24, 25 }, { 26, 27 }, { 29, 28 }, { 31, 30 },
+	{ 32, 33 }, { 34, 35 }, { 37, 36 }, { 39, 38 },
+	{ 41, 40 }, { 43, 42 }, { 44, 45 }, { 46, 47 },
+	{ 48, 49 }, { 50, 51 }, { 53, 52 }, { 55, 54 },
+	{ 57, 56 }, { 59, 58 }, { 60, 61 }, { 62, 63 },
+};
+
+static const uint8_t conv_tch_ahs_4_75_next_term_output[] = {
+	 0,  3,  5,  6,  5,  6,  0,  3,  3,  0,  6,  5,  6,  5,  3,  0,
+	 4,  7,  1,  2,  1,  2,  4,  7,  7,  4,  2,  1,  2,  1,  7,  4,
+	 7,  4,  2,  1,  2,  1,  7,  4,  4,  7,  1,  2,  1,  2,  4,  7,
+	 3,  0,  6,  5,  6,  5,  3,  0,  0,  3,  5,  6,  5,  6,  0,  3,
+};
+
+static const uint8_t conv_tch_ahs_4_75_next_term_state[] = {
+	 0,  2,  4,  6,  8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30,
+	32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62,
+	 0,  2,  4,  6,  8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30,
+	32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62,
+};
+
+static int conv_tch_ahs_4_75_puncture[] = {
+	  1,   2,   4,   5,   7,   8,  10,  13,  16,  22,  28,  34,
+	 40,  46,  52,  58, 64,  70,  76,  82,  88,  94, 100, 106,
+	112, 118, 124, 130, 136, 142, 148, 151, 154, 160, 163, 166,
+	172, 175, 178, 184, 187, 190, 196, 199, 202, 208, 211, 214,
+	220, 223, 226, 232, 235, 238, 241, 244, 247, 250, 253, 256,
+	259, 262, 265, 268, 271, 274, 275, 277, 278, 280, 281, 283,
+	284,
+	-1, /* end */
+};
+
+const struct osmo_conv_code gsm0503_conv_tch_ahs_4_75 = {
+	.N = 3,
+	.K = 7,
+	.len = 89,
+	.next_output      = conv_tch_ahs_4_75_next_output,
+	.next_state       = conv_tch_ahs_4_75_next_state,
+	.next_term_output = conv_tch_ahs_4_75_next_term_output,
+	.next_term_state  = conv_tch_ahs_4_75_next_term_state,
+	.puncture         = conv_tch_ahs_4_75_puncture,
+};
+
diff --git a/src/osmo-bts-trx/gsm0503_conv.h b/src/osmo-bts-trx/gsm0503_conv.h
index 045a0959..68ad4844 100644
--- a/src/osmo-bts-trx/gsm0503_conv.h
+++ b/src/osmo-bts-trx/gsm0503_conv.h
@@ -16,5 +16,11 @@ extern const struct osmo_conv_code gsm0503_conv_tch_afs_6_7;
 extern const struct osmo_conv_code gsm0503_conv_tch_afs_5_9;
 extern const struct osmo_conv_code gsm0503_conv_tch_afs_5_15;
 extern const struct osmo_conv_code gsm0503_conv_tch_afs_4_75;
+extern const struct osmo_conv_code gsm0503_conv_tch_ahs_7_95;
+extern const struct osmo_conv_code gsm0503_conv_tch_ahs_7_4;
+extern const struct osmo_conv_code gsm0503_conv_tch_ahs_6_7;
+extern const struct osmo_conv_code gsm0503_conv_tch_ahs_5_9;
+extern const struct osmo_conv_code gsm0503_conv_tch_ahs_5_15;
+extern const struct osmo_conv_code gsm0503_conv_tch_ahs_4_75;
 
 #endif /* _0503_CONV_H */
diff --git a/src/osmo-bts-trx/gsm0503_tables.c b/src/osmo-bts-trx/gsm0503_tables.c
index 1c272d8f..a3817842 100644
--- a/src/osmo-bts-trx/gsm0503_tables.c
+++ b/src/osmo-bts-trx/gsm0503_tables.c
@@ -136,6 +136,20 @@ const sbit_t gsm0503_afs_ic_sbit[4][8] = {
 	{ -127,-127,-127, 127, 127,-127,-127,-127 },
 };
 
+const ubit_t gsm0503_ahs_ic_ubit[4][4] = {
+	{ 0,0,0,0 },
+	{ 1,0,0,1 },
+	{ 1,1,1,0 },
+	{ 0,1,1,1 },
+};
+
+const sbit_t gsm0503_ahs_ic_sbit[4][4] = {
+	{  127, 127, 127, 127 },
+	{ -127, 127, 127,-127 },
+	{ -127,-127,-127, 127 },
+	{  127,-127,-127,-127 },
+};
+
 const uint8_t gsm0503_tch_hr_interleaving[228][2] = {
 	{ 0  ,0 }, { 1  ,2 }, { 78 ,1 }, { 79 ,3 }, { 48 ,0 }, { 49 ,2 },
 	{ 54 ,1 }, { 55 ,3 }, { 24 ,0 }, { 25 ,2 }, { 30 ,1 }, { 31 ,3 },
diff --git a/src/osmo-bts-trx/gsm0503_tables.h b/src/osmo-bts-trx/gsm0503_tables.h
index b068fdd6..63b45a4d 100644
--- a/src/osmo-bts-trx/gsm0503_tables.h
+++ b/src/osmo-bts-trx/gsm0503_tables.h
@@ -12,6 +12,8 @@ extern const uint8_t gsm0503_gsm_fr_map[76];
 extern const uint8_t gsm0503_gsm_efr_protected_bits[65];
 extern const ubit_t gsm0503_afs_ic_ubit[4][8];
 extern const sbit_t gsm0503_afs_ic_sbit[4][8];
+extern const ubit_t gsm0503_ahs_ic_ubit[4][4];
+extern const sbit_t gsm0503_ahs_ic_sbit[4][4];
 extern const uint8_t gsm0503_tch_hr_interleaving[228][2];
 
 #endif /* _0503_TABLES_H */
diff --git a/src/osmo-bts-trx/scheduler.c b/src/osmo-bts-trx/scheduler.c
index 65da30eb..9126e342 100644
--- a/src/osmo-bts-trx/scheduler.c
+++ b/src/osmo-bts-trx/scheduler.c
@@ -1065,6 +1065,7 @@ static ubit_t *tx_tchh_fn(struct trx_l1h *l1h, uint8_t tn, uint32_t fn,
 {
 	struct msgb *msg_tch = NULL, *msg_facch = NULL;
 	struct trx_chan_state *chan_state = &l1h->chan_states[tn][chan];
+	uint8_t tch_mode = chan_state->tch_mode;
 	ubit_t *burst, **bursts_p = &chan_state->dl_bursts;
 	static ubit_t bits[148];
 
@@ -1118,6 +1119,15 @@ static ubit_t *tx_tchh_fn(struct trx_l1h *l1h, uint8_t tn, uint32_t fn,
 		chan_state->dl_ongoing_facch = 1; /* first of two tch frames */
 	} else if (chan_state->dl_ongoing_facch) /* second of two tch frames */
 		chan_state->dl_ongoing_facch = 0; /* we are done with FACCH */
+	else if (tch_mode == GSM48_CMODE_SPEECH_AMR)
+		/* the first FN 4,13,21 or 5,14,22 defines that CMI is included
+		 * in frame, the first FN 0,8,17 or 1,9,18 defines that CMR is
+		 * included in frame. */
+		tch_ahs_encode(*bursts_p, msg_tch->l2h + 2,
+			msgb_l2len(msg_tch) - 2, (((fn + 4) % 26) >> 2) & 1,
+			chan_state->codec, chan_state->codecs,
+			chan_state->dl_ft,
+			chan_state->dl_cmr);
 	else
 		tch_hr_encode(*bursts_p, msg_tch->l2h, msgb_l2len(msg_tch));
 
@@ -1486,6 +1496,7 @@ static int rx_tchh_fn(struct trx_l1h *l1h, uint8_t tn, uint32_t fn,
 	uint8_t tch_mode = chan_state->tch_mode;
 	uint8_t tch_data[128]; /* just to be safe */
 	int rc, amr = 0;
+	float ber;
 
 	LOGP(DL1C, LOGL_DEBUG, "TCH/H received %s fn=%u ts=%u trx=%u bid=%u\n", 
 		trx_chan_desc[chan].name, fn, tn, l1h->trx->nr, bid);
@@ -1544,6 +1555,28 @@ static int rx_tchh_fn(struct trx_l1h *l1h, uint8_t tn, uint32_t fn,
 		rc = tch_hr_decode(tch_data, *bursts_p,
 			(((fn + 26 - 10) % 26) >> 2) & 1);
 		break;
+	case GSM48_CMODE_SPEECH_AMR: /* AMR */
+		/* the first FN 0,8,17 or 1,9,18 defines that CMI is included
+		 * in frame, the first FN 4,13,21 or 5,14,22 defines that CMR
+		 * is included in frame.
+		 */
+		rc = tch_ahs_decode(tch_data + 2, *bursts_p,
+			(((fn + 26 - 10) % 26) >> 2) & 1,
+			(((fn + 26 - 10) % 26) >> 2) & 1, chan_state->codec,
+			chan_state->codecs, &chan_state->ul_ft,
+			&chan_state->ul_cmr, &ber);
+		if (rc)
+			trx_loop_amr_input(l1h,
+				trx_chan_desc[chan].chan_nr | tn, chan_state,
+				ber);
+		amr = 2; /* we store tch_data + 2 two */
+		/* only good speech frames get rtp header */
+		if (rc != 23 && rc >= 4) {
+			rc = amr_compose_payload(tch_data,
+				chan_state->codec[chan_state->ul_cmr],
+				chan_state->codec[chan_state->ul_ft], 0);
+		}
+		break;
 	default:
 		LOGP(DL1C, LOGL_ERROR, "TCH mode %u invalid, please fix!\n",
 			tch_mode);
@@ -1578,6 +1611,15 @@ bfi:
 				memset(tch_data + 1, 0, 14);
 				rc = 15;
 				break;
+			case GSM48_CMODE_SPEECH_AMR: /* AMR */
+				rc = amr_compose_payload(tch_data,
+					chan_state->codec[chan_state->dl_cmr],
+					chan_state->codec[chan_state->dl_ft],
+					1);
+				if (rc < 2)
+					break;
+				memset(tch_data + 2, 0, rc - 2);
+				break;
 			default:
 				LOGP(DL1C, LOGL_ERROR, "TCH mode invalid, "
 					"please fix!\n");