fixeria has submitted this change. (
https://gerrit.osmocom.org/c/osmo-bts/+/33586 )
(
9 is the latest approved patch-set.
No files were changed between the latest approved patch-set and the submitted
one.
)Change subject: osmo-bts-trx: implement FACCH/[FH] support for CSD
......................................................................
osmo-bts-trx: implement FACCH/[FH] support for CSD
The FACCH/[FH] coding rules are specified in 3GPP TS 45.003, sections
4.2 and 4.3. The key difference is that unlike with speech channels,
FACCH does not replace data frames completely, but disturb a fixed
amount of bits fom them. This is why we need to use separate
gsm0503_tch_[fh]r_facch_{en,de}code() API for data channels.
Change-Id: I4c6736e84c271240d457998de688c0baf59fe578
Depends: libosmocore.git I0c7a9c180dcafe64e6aebe53518d3d11e1f29886
Related: OS#1572
---
M src/osmo-bts-trx/sched_lchan_tchf.c
M src/osmo-bts-trx/sched_lchan_tchh.c
2 files changed, 160 insertions(+), 57 deletions(-)
Approvals:
laforge: Looks good to me, approved
Jenkins Builder: Verified
diff --git a/src/osmo-bts-trx/sched_lchan_tchf.c
b/src/osmo-bts-trx/sched_lchan_tchf.c
index ac9a15c..b98373e 100644
--- a/src/osmo-bts-trx/sched_lchan_tchf.c
+++ b/src/osmo-bts-trx/sched_lchan_tchf.c
@@ -69,6 +69,34 @@
extern const uint8_t sched_tchh_dl_amr_cmi_map[26];
+static int decode_fr_facch(struct l1sched_ts *l1ts,
+ const struct trx_ul_burst_ind *bi)
+{
+ struct l1sched_chan_state *chan_state = &l1ts->chan_state[bi->chan];
+ const sbit_t *bursts_p = chan_state->ul_bursts;
+ struct l1sched_meas_set meas_avg;
+ uint8_t data[GSM_MACBLOCK_LEN];
+ int n_errors, n_bits_total;
+ int rc;
+
+ rc = gsm0503_tch_fr_facch_decode(&data[0], BUFTAIL8(bursts_p),
+ &n_errors, &n_bits_total);
+ if (rc != GSM_MACBLOCK_LEN)
+ return rc;
+
+ /* average measurements of the last 8 bursts, obtain TDMA Fn of the
first burst */
+ trx_sched_meas_avg(chan_state, &meas_avg, SCHED_MEAS_AVG_M_S8N8);
+
+ _sched_compose_ph_data_ind(l1ts, meas_avg.fn, bi->chan,
+ &data[0], GSM_MACBLOCK_LEN,
+ compute_ber10k(n_bits_total, n_errors),
+ meas_avg.rssi,
+ meas_avg.toa256,
+ meas_avg.ci_cb,
+ PRES_INFO_UNKNOWN);
+ return GSM_MACBLOCK_LEN;
+}
+
/*! \brief a single TCH/F burst was received by the PHY, process it */
int rx_tchf_fn(struct l1sched_ts *l1ts, const struct trx_ul_burst_ind *bi)
{
@@ -224,12 +252,16 @@
break;
/* CSD (TCH/F9.6): 12.0 kbit/s radio interface rate */
case GSM48_CMODE_DATA_12k0:
+ /* FACCH/F does not steal TCH/F9.6 frames, but only disturbs
some bits */
+ decode_fr_facch(l1ts, bi);
rc = gsm0503_tch_fr96_decode(&tch_data[0], BUFPOS(bursts_p, 0),
&n_errors, &n_bits_total);
meas_avg_mode = SCHED_MEAS_AVG_M_S24N22;
break;
/* CSD (TCH/F4.8): 6.0 kbit/s radio interface rate */
case GSM48_CMODE_DATA_6k0:
+ /* FACCH/F does not steal TCH/F4.8 frames, but only disturbs
some bits */
+ decode_fr_facch(l1ts, bi);
rc = gsm0503_tch_fr48_decode(&tch_data[0], BUFPOS(bursts_p, 0),
&n_errors, &n_bits_total);
meas_avg_mode = SCHED_MEAS_AVG_M_S24N22;
@@ -237,7 +269,8 @@
#if 0
/* TODO: CSD (TCH/F2.4): 3.6 kbit/s radio interface rate */
case GSM48_CMODE_DATA_3k6:
- /* TCH/F2.4 employs the same interleaving as TCH/FS (8 bursts)
*/
+ /* TCH/F2.4 employs the same interleaving as TCH/FS (8 bursts),
+ * so FACCH/F *does* steal TCH/F2.4 frames completely. */
rc = gsm0503_tch_fr24_decode(&tch_data[0], BUFTAIL8(bursts_p),
&n_errors, &n_bits_total);
meas_avg_mode = SCHED_MEAS_AVG_M_S8N8;
@@ -245,6 +278,8 @@
#endif
/* CSD (TCH/F14.4): 14.5 kbit/s radio interface rate */
case GSM48_CMODE_DATA_14k5:
+ /* FACCH/F does not steal TCH/F14.4 frames, but only disturbs
some bits */
+ decode_fr_facch(l1ts, bi);
rc = gsm0503_tch_fr144_decode(&tch_data[0], BUFPOS(bursts_p, 0),
&n_errors, &n_bits_total);
meas_avg_mode = SCHED_MEAS_AVG_M_S24N22;
@@ -316,9 +351,10 @@
/* common section for generation of TCH bursts (TCH/H and TCH/F).
* FIXME: this function is over-complicated, refactor / get rid of it. */
-struct msgb *tch_dl_dequeue(struct l1sched_ts *l1ts, struct trx_dl_burst_req
*br)
+void tch_dl_dequeue(struct l1sched_ts *l1ts, struct trx_dl_burst_req *br,
+ struct msgb **msg_tch, struct msgb **msg_facch)
{
- struct msgb *msg1, *msg2, *msg_tch = NULL, *msg_facch = NULL;
+ struct msgb *msg1, *msg2;
struct l1sched_chan_state *chan_state = &l1ts->chan_state[br->chan];
uint8_t rsl_cmode = chan_state->rsl_cmode;
uint8_t tch_mode = chan_state->tch_mode;
@@ -330,50 +366,39 @@
if (msg1) {
l1sap = msgb_l1sap_prim(msg1);
if (l1sap->oph.primitive == PRIM_TCH) {
- msg_tch = msg1;
+ *msg_tch = msg1;
if (msg2) {
l1sap = msgb_l1sap_prim(msg2);
if (l1sap->oph.primitive == PRIM_TCH) {
LOGL1SB(DL1P, LOGL_FATAL, l1ts, br,
"TCH twice, please FIX!\n");
msgb_free(msg2);
} else
- msg_facch = msg2;
+ *msg_facch = msg2;
}
} else {
- msg_facch = msg1;
+ *msg_facch = msg1;
if (msg2) {
l1sap = msgb_l1sap_prim(msg2);
if (l1sap->oph.primitive != PRIM_TCH) {
LOGL1SB(DL1P, LOGL_FATAL, l1ts, br,
"FACCH twice, please FIX!\n");
msgb_free(msg2);
} else
- msg_tch = msg2;
+ *msg_tch = msg2;
}
}
}
/* check validity of message */
- if (msg_facch && msgb_l2len(msg_facch) != GSM_MACBLOCK_LEN) {
+ if (*msg_facch != NULL && msgb_l2len(*msg_facch) != GSM_MACBLOCK_LEN) {
LOGL1SB(DL1P, LOGL_FATAL, l1ts, br, "Prim has odd len=%u !=
%u\n",
- msgb_l2len(msg_facch), GSM_MACBLOCK_LEN);
+ msgb_l2len(*msg_facch), GSM_MACBLOCK_LEN);
/* free message */
- msgb_free(msg_facch);
- msg_facch = NULL;
- }
-
- /* prioritize FACCH over speech */
- if (msg_facch) {
- /* Unlike SACCH, FACCH has no dedicated slots on the multiframe
layout.
- * It's multiplexed together with TCH (speech or data) frames
basically
- * by replacing (stealing) them. This is common for both TCH/F
and
- * TCH/H, with the only difference that FACCH/H steals two TCH
frames
- * (not just one) due to a longer interleaving period. */
- msgb_free(msg_tch);
- return msg_facch;
+ msgb_free(*msg_facch);
+ *msg_facch = NULL;
}
/* check validity of message, get AMR ft and cmr */
- if (msg_tch) {
+ if (*msg_tch != NULL) {
int len;
uint8_t cmr_codec;
int ft, i;
@@ -401,7 +426,7 @@
len = GSM_EFR_BYTES;
break;
case GSM48_CMODE_SPEECH_AMR: /* AMR */
- len = osmo_amr_rtp_dec(msg_tch->l2h,
msgb_l2len(msg_tch),
+ len = osmo_amr_rtp_dec(msgb_l2((*msg_tch)),
msgb_l2len(*msg_tch),
&cmr_codec, &cmi, &ft_codec,
&bfi, &sti);
if (len < 0) {
@@ -433,7 +458,7 @@
goto free_bad_msg;
}
/* pull the AMR header, it's not being sent over Um */
- msg_tch->l2h += sizeof(struct amr_hdr);
+ (*msg_tch)->l2h += sizeof(struct amr_hdr);
len -= sizeof(struct amr_hdr);
break;
case GSM48_CMODE_DATA_14k5: /* TCH/F14.4 */
@@ -464,18 +489,16 @@
LOGL1SB(DL1P, LOGL_ERROR, l1ts, br, "TCH mode invalid,
please fix!\n");
goto free_bad_msg;
}
- if (msgb_l2len(msg_tch) != len) {
+ if (msgb_l2len(*msg_tch) != len) {
LOGL1SB(DL1P, LOGL_ERROR, l1ts, br, "Cannot send
payload with "
"invalid length! (expecting %d, received %d)\n",
- len, msgb_l2len(msg_tch));
+ len, msgb_l2len(*msg_tch));
free_bad_msg:
/* free message */
- msgb_free(msg_tch);
- msg_tch = NULL;
+ msgb_free(*msg_tch);
+ *msg_tch = NULL;
}
}
-
- return msg_tch;
}
/* obtain a to-be-transmitted TCH/F (Full Traffic Channel) burst */
@@ -485,7 +508,9 @@
uint8_t tch_mode = chan_state->tch_mode;
ubit_t *burst, *bursts_p = chan_state->dl_bursts;
uint8_t *mask = &chan_state->dl_mask;
- struct msgb *msg;
+ struct msgb *msg_facch = NULL;
+ struct msgb *msg_tch = NULL;
+ struct msgb *msg = NULL;
/* send burst, if we already got a frame */
if (br->bid > 0) {
@@ -502,11 +527,9 @@
memmove(BUFPOS(bursts_p, 0), BUFPOS(bursts_p, 4), 20 * BPLEN);
memset(BUFPOS(bursts_p, 20), 0, 4 * BPLEN);
- /* dequeue a message to be transmitted */
- msg = tch_dl_dequeue(l1ts, br);
-
- /* no message at all, send a dummy L2 frame on FACCH */
- if (msg == NULL) {
+ /* dequeue a TCH and/or a FACCH message to be transmitted */
+ tch_dl_dequeue(l1ts, br, &msg_tch, &msg_facch);
+ if (msg_tch == NULL && msg_facch == NULL) {
static const uint8_t dummy[GSM_MACBLOCK_LEN] = {
0x03, 0x03, 0x01, /* TODO: use randomized padding */
0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b,
0x2b,
@@ -538,7 +561,11 @@
goto send_burst;
}
- if (msgb_l2len(msg) == GSM_MACBLOCK_LEN)
+ /* Unlike SACCH, FACCH has no dedicated slots on the multiframe layout.
+ * It's multiplexed together with TCH (speech or data) frames basically
+ * by replacing (stealing) their bits, either completely or partly. */
+ msg = (msg_facch != NULL) ? msg_facch : msg_tch;
+ if (msg == msg_facch)
chan_state->dl_facch_bursts = 8;
/* populate the buffer with bursts */
@@ -562,28 +589,39 @@
break;
/* CSD (TCH/F9.6): 12.0 kbit/s radio interface rate */
case GSM48_CMODE_DATA_12k0:
- gsm0503_tch_fr96_encode(BUFPOS(bursts_p, 0), msgb_l2(msg));
+ gsm0503_tch_fr96_encode(BUFPOS(bursts_p, 0), msgb_l2(msg_tch));
+ if (msg_facch != NULL)
+ gsm0503_tch_fr_facch_encode(BUFPOS(bursts_p, 0),
msgb_l2(msg_facch));
break;
/* CSD (TCH/F4.8): 6.0 kbit/s radio interface rate */
case GSM48_CMODE_DATA_6k0:
- gsm0503_tch_fr48_encode(BUFPOS(bursts_p, 0), msgb_l2(msg));
+ gsm0503_tch_fr48_encode(BUFPOS(bursts_p, 0), msgb_l2(msg_tch));
+ if (msg_facch != NULL)
+ gsm0503_tch_fr_facch_encode(BUFPOS(bursts_p, 0),
msgb_l2(msg_facch));
break;
#if 0
/* TODO: CSD (TCH/F2.4): 3.6 kbit/s radio interface rate */
case GSM48_CMODE_DATA_3k6:
- gsm0503_tch_fr24_encode(BUFPOS(bursts_p, 0), msgb_l2(msg));
+ /* FACCH/F does steal a TCH/F2.4 frame completely */
+ if (msg == msg_facch)
+ gsm0503_tch_fr_facch_encode(BUFPOS(bursts_p, 0),
msgb_l2(msg_facch));
+ else
+ gsm0503_tch_fr24_encode(BUFPOS(bursts_p, 0),
msgb_l2(msg_tch));
break;
#endif
/* CSD (TCH/F14.4): 14.5 kbit/s radio interface rate */
case GSM48_CMODE_DATA_14k5:
- gsm0503_tch_fr144_encode(BUFPOS(bursts_p, 0), msgb_l2(msg));
+ gsm0503_tch_fr144_encode(BUFPOS(bursts_p, 0), msgb_l2(msg_tch));
+ if (msg_facch != NULL)
+ gsm0503_tch_fr_facch_encode(BUFPOS(bursts_p, 0),
msgb_l2(msg_facch));
break;
default:
OSMO_ASSERT(0);
}
- /* free message */
- msgb_free(msg);
+ /* free messages */
+ msgb_free(msg_tch);
+ msgb_free(msg_facch);
send_burst:
/* compose burst */
diff --git a/src/osmo-bts-trx/sched_lchan_tchh.c
b/src/osmo-bts-trx/sched_lchan_tchh.c
index 6ab4c31..1f65d4f 100644
--- a/src/osmo-bts-trx/sched_lchan_tchh.c
+++ b/src/osmo-bts-trx/sched_lchan_tchh.c
@@ -126,6 +126,34 @@
[18] = 1, /* TCH/H(1): B2(18 ... 11) */
};
+static int decode_hr_facch(struct l1sched_ts *l1ts,
+ const struct trx_ul_burst_ind *bi)
+{
+ struct l1sched_chan_state *chan_state = &l1ts->chan_state[bi->chan];
+ const sbit_t *bursts_p = chan_state->ul_bursts;
+ struct l1sched_meas_set meas_avg;
+ uint8_t data[GSM_MACBLOCK_LEN];
+ int n_errors, n_bits_total;
+ int rc;
+
+ rc = gsm0503_tch_hr_facch_decode(&data[0], BUFTAIL8(bursts_p),
+ &n_errors, &n_bits_total);
+ if (rc != GSM_MACBLOCK_LEN)
+ return rc;
+
+ /* average measurements of the last 6 bursts, obtain TDMA Fn of the
first burst */
+ trx_sched_meas_avg(chan_state, &meas_avg, SCHED_MEAS_AVG_M_S6N6);
+
+ _sched_compose_ph_data_ind(l1ts, meas_avg.fn, bi->chan,
+ &data[0], GSM_MACBLOCK_LEN,
+ compute_ber10k(n_bits_total, n_errors),
+ meas_avg.rssi,
+ meas_avg.toa256,
+ meas_avg.ci_cb,
+ PRES_INFO_UNKNOWN);
+ return GSM_MACBLOCK_LEN;
+}
+
/*! \brief a single TCH/H burst was received by the PHY, process it */
int rx_tchh_fn(struct l1sched_ts *l1ts, const struct trx_ul_burst_ind *bi)
{
@@ -295,6 +323,8 @@
case GSM48_CMODE_DATA_6k0:
if (!sched_tchh_ul_csd_map[bi->fn % 26])
return 0; /* CSD: skip decoding attempt, need 2 more
bursts */
+ /* FACCH/F does not steal TCH/H4.8 frames, but only disturbs
some bits */
+ decode_hr_facch(l1ts, bi);
rc = gsm0503_tch_hr48_decode(&tch_data[0], BUFPOS(bursts_p, 0),
&n_errors, &n_bits_total);
meas_avg_mode = SCHED_MEAS_AVG_M_S22N22;
@@ -303,6 +333,8 @@
case GSM48_CMODE_DATA_3k6:
if (!sched_tchh_ul_csd_map[bi->fn % 26])
return 0; /* CSD: skip decoding attempt, need 2 more
bursts */
+ /* FACCH/F does not steal TCH/H2.4 frames, but only disturbs
some bits */
+ decode_hr_facch(l1ts, bi);
rc = gsm0503_tch_hr24_decode(&tch_data[0], BUFPOS(bursts_p, 0),
&n_errors, &n_bits_total);
meas_avg_mode = SCHED_MEAS_AVG_M_S22N22;
@@ -375,7 +407,8 @@
/* common section for generation of TCH bursts (TCH/H and TCH/F).
* FIXME: this function is over-complicated, refactor / get rid of it. */
-extern struct msgb *tch_dl_dequeue(struct l1sched_ts *l1ts, const struct
trx_dl_burst_req *br);
+extern void tch_dl_dequeue(struct l1sched_ts *l1ts, const struct
trx_dl_burst_req *br,
+ struct msgb **msg_tch, struct msgb **msg_facch);
/* obtain a to-be-transmitted TCH/H (Half Traffic Channel) burst */
int tx_tchh_fn(struct l1sched_ts *l1ts, struct trx_dl_burst_req *br)
@@ -384,7 +417,9 @@
uint8_t tch_mode = chan_state->tch_mode;
ubit_t *burst, *bursts_p = chan_state->dl_bursts;
uint8_t *mask = &chan_state->dl_mask;
- struct msgb *msg;
+ struct msgb *msg_facch = NULL;
+ struct msgb *msg_tch = NULL;
+ struct msgb *msg = NULL;
/* send burst, if we already got a frame */
if (br->bid > 0) {
@@ -407,18 +442,20 @@
goto send_burst;
}
- /* dequeue a message to be transmitted */
- msg = tch_dl_dequeue(l1ts, br);
+ /* dequeue a TCH and/or a FACCH message to be transmitted */
+ tch_dl_dequeue(l1ts, br, &msg_tch, &msg_facch);
/* if we're sending 2 middle bursts of FACCH/H */
if (chan_state->dl_ongoing_facch) {
- msgb_free(msg); /* drop 2nd speech frame */
+ /* FACCH/H shall not be scheduled at wrong FNs */
+ OSMO_ASSERT(msg_facch == NULL);
+ msgb_free(msg_tch); /* drop 2nd speech frame */
chan_state->dl_ongoing_facch = 0;
goto send_burst;
}
/* no message at all, send a dummy L2 frame on FACCH */
- if (msg == NULL) {
+ if (msg_tch == NULL && msg_facch == NULL) {
static const uint8_t dummy[GSM_MACBLOCK_LEN] = {
0x03, 0x03, 0x01, /* TODO: use randomized padding */
0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b,
0x2b,
@@ -451,13 +488,19 @@
}
gsm0503_tch_hr_encode(BUFPOS(bursts_p, 0), dummy,
sizeof(dummy));
- chan_state->dl_ongoing_facch = 1;
+ if (chan_state->rsl_cmode != RSL_CMOD_SPD_DATA)
+ chan_state->dl_ongoing_facch = 1;
chan_state->dl_facch_bursts = 6;
goto send_burst;
}
- if (msgb_l2len(msg) == GSM_MACBLOCK_LEN) {
- chan_state->dl_ongoing_facch = 1; /* first of two TCH frames */
+ /* Unlike SACCH, FACCH has no dedicated slots on the multiframe layout.
+ * It's multiplexed together with TCH (speech or data) frames basically
+ * by replacing (stealing) their bits, either completely or partly. */
+ msg = (msg_facch != NULL) ? msg_facch : msg_tch;
+ if (msg == msg_facch) {
+ if (chan_state->rsl_cmode != RSL_CMOD_SPD_DATA)
+ chan_state->dl_ongoing_facch = 1;
chan_state->dl_facch_bursts = 6;
}
@@ -481,18 +524,23 @@
break;
/* CSD (TCH/H4.8): 6.0 kbit/s radio interface rate */
case GSM48_CMODE_DATA_6k0:
- gsm0503_tch_hr48_encode(BUFPOS(bursts_p, 0), msgb_l2(msg));
+ gsm0503_tch_hr48_encode(BUFPOS(bursts_p, 0), msgb_l2(msg_tch));
+ if (msg_facch != NULL)
+ gsm0503_tch_hr_facch_encode(BUFPOS(bursts_p, 0),
msgb_l2(msg_facch));
break;
/* CSD (TCH/H2.4): 3.6 kbit/s radio interface rate */
case GSM48_CMODE_DATA_3k6:
- gsm0503_tch_hr24_encode(BUFPOS(bursts_p, 0), msgb_l2(msg));
+ gsm0503_tch_hr24_encode(BUFPOS(bursts_p, 0), msgb_l2(msg_tch));
+ if (msg_facch != NULL)
+ gsm0503_tch_hr_facch_encode(BUFPOS(bursts_p, 0),
msgb_l2(msg_facch));
break;
default:
OSMO_ASSERT(0);
}
- /* free message */
- msgb_free(msg);
+ /* free messages */
+ msgb_free(msg_tch);
+ msgb_free(msg_facch);
send_burst:
/* compose burst */
--
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Gerrit-Project: osmo-bts
Gerrit-Branch: master
Gerrit-Change-Id: I4c6736e84c271240d457998de688c0baf59fe578
Gerrit-Change-Number: 33586
Gerrit-PatchSet: 10
Gerrit-Owner: fixeria <[email protected]>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: fixeria <[email protected]>
Gerrit-Reviewer: laforge <[email protected]>
Gerrit-Reviewer: pespin <[email protected]>
Gerrit-MessageType: merged
