Stefan Sperling has uploaded this change for review. (
https://gerrit.osmocom.org/10415
Change subject: send TCH/F fill frames in DTX mode (WIP)
......................................................................
send TCH/F fill frames in DTX mode (WIP)
Send DTX TCH fill frames according to GSM 05.08, section 8.3.
Change-Id: I7bff00b8cf41dc1b0e6e668173bebce23be0d253
Related: OS#1950
---
M src/common/l1sap.c
1 file changed, 52 insertions(+), 13 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/osmo-bts refs/changes/15/10415/1
diff --git a/src/common/l1sap.c b/src/common/l1sap.c
index 8d735e5..ed818cb 100644
--- a/src/common/l1sap.c
+++ b/src/common/l1sap.c
@@ -670,6 +670,19 @@
return 0;
}
+ /* Determine whether we need to send a DTX TCH fill frame according to GSM
05.08, section 8.3. */
+static bool is_required_tchf_fill_frame_dtx(uint32_t fn) {
+ /* On TCHF this subset of TDMA frames (mod 104) is always used for
transmission during DTX: */
+ const int tchf_required_fn_dtx[] = { 52, 53, 54, 55, 56, 57, 58, 59 };
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(tchf_required_fn_dtx); i++) {
+ if (fn % 104 == tchf_required_fn_dtx[i])
+ return true;
+ }
+ return false;
+}
+
/* PH-RTS-IND prim received from bts model */
static int l1sap_ph_rts_ind(struct gsm_bts_trx *trx,
struct osmo_phsap_prim *l1sap, struct ph_data_param *rts_ind)
@@ -729,14 +742,18 @@
si = bts_sysinfo_get(trx->bts, &g_time);
if (si)
memcpy(p, si, GSM_MACBLOCK_LEN);
- else
+ else {
memcpy(p, fill_frame, GSM_MACBLOCK_LEN);
+ DEBUGPGT(DL1P, &g_time, "sending fill frame BCCH
chan_nr=%d fn=%u\n", chan_nr, fn);
+ }
} else if (!(chan_nr & 0x80)) { /* only TCH/F, TCH/H, SDCCH/4 and
SDCCH/8 have C5 bit cleared */
+ bool dtxd = false;
lchan = get_active_lchan_by_chan_nr(trx, chan_nr);
if (!lchan) {
LOGPGT(DL1P, LOGL_ERROR, &g_time, "No lchan for
PH-RTS.ind (chan_nr=%u)\n", chan_nr);
return 0;
}
+ dtxd = lchan->ts->trx->bts->dtxd;
if (L1SAP_IS_LINK_SACCH(link_id)) {
p = msgb_put(msg, GSM_MACBLOCK_LEN);
/* L1-header, if not set/modified by layer 1 */
@@ -756,20 +773,39 @@
if (si) {
/* The +2 is empty space where the DSP
inserts the L1 hdr */
memcpy(p + 2, si, GSM_MACBLOCK_LEN - 2);
- } else
+ } else {
memcpy(p + 2, fill_frame,
GSM_MACBLOCK_LEN - 2);
- } else if (L1SAP_IS_CHAN_SDCCH4(chan_nr) ||
L1SAP_IS_CHAN_SDCCH8(chan_nr) ||
- (lchan->rsl_cmode == RSL_CMOD_SPD_SIGN &&
!lchan->ts->trx->bts->dtxd)) {
- /*
- * SDCCH or TCH in signalling mode without DTX.
- *
- * Send fill frame according to GSM 05.08,
section 8.3: "On the SDCCH and on the
- * half rate speech traffic channel in
signalling only mode DTX is not allowed.
- * In these cases and during signalling on the
TCH when DTX is not used, the same
- * L2 fill frame shall be transmitted in case
there is nothing else to transmit."
- */
+ DEBUGPGT(DL1P, &g_time, "sending fill
frame SACCH chan_nr=%d fn=%u dtx=%s\n", chan_nr, fn, dtxd ? "enabled" :
"disabled");
+ }
+ } else if (L1SAP_IS_CHAN_SDCCH4(chan_nr) ||
L1SAP_IS_CHAN_SDCCH8(chan_nr)) {
p = msgb_put(msg, GSM_MACBLOCK_LEN);
memcpy(p, fill_frame, GSM_MACBLOCK_LEN);
+ DEBUGPGT(DL1P, &g_time, "sending fill frame
SDCCH chan_nr=%d fn=%u dtx=%s\n", chan_nr, fn, dtxd ? "enabled" : "disabled");
+ } else if (lchan->rsl_cmode == RSL_CMOD_SPD_SIGN) {
+ if (lchan->ts->trx->bts->dtxd) {
+ /*
+ * TCH in signalling mode with DTX.
+ * Send fill frame according to GSM
05.08, section 8.3.
+ */
+ if (L1SAP_IS_CHAN_TCHF(chan_nr) &&
is_required_tchf_fill_frame_dtx(fn)) {
+ p = msgb_put(msg,
GSM_MACBLOCK_LEN);
+ memcpy(p, fill_frame,
GSM_MACBLOCK_LEN);
+ DEBUGPGT(DL1P, &g_time,
"sending fill frame TCH chan_nr=%d fn=%u dtx=%s\n", chan_nr, fn, dtxd ?
"enabled" : "disabled");
+ //dtx_dispatch(lchan, E_FACCH);
+ }
+ } else {
+ /*
+ * TCH in signalling mode without DTX.
+ *
+ * Send fill frame according to GSM
05.08, section 8.3: "On the SDCCH and on the
+ * half rate speech traffic channel in
signalling only mode DTX is not allowed.
+ * In these cases and during signalling
on the TCH when DTX is not used, the same
+ * L2 fill frame shall be transmitted
in case there is nothing else to transmit."
+ */
+ p = msgb_put(msg, GSM_MACBLOCK_LEN);
+ memcpy(p, fill_frame, GSM_MACBLOCK_LEN);
+ DEBUGPGT(DL1P, &g_time, "sending fill
frame TCH chan_nr=%d fn=%u dtx=%s\n", chan_nr, fn, dtxd ? "enabled" :
"disabled");
+ }
} /* else the message remains empty, so TCH frames are
sent */
} else {
/* The +2 is empty space where the DSP inserts the L1
hdr */
@@ -790,8 +826,10 @@
rc = bts_ccch_copy_msg(trx->bts, p, &g_time,
(L1SAP_FN2CCCHBLOCK(fn) <
num_agch(trx, "PH-RTS-IND")));
- if (rc <= 0)
+ if (rc <= 0) {
memcpy(p, fill_frame, GSM_MACBLOCK_LEN);
+ DEBUGPGT(DL1P, &g_time, "sending fill frame AGCH PCH
chan_nr=%d fn=%u\n", chan_nr, fn);
+ }
}
DEBUGPGT(DL1P, &g_time, "Tx PH-DATA.req chan_nr=0x%02x
link_id=0x%02x\n", chan_nr, link_id);
@@ -1440,6 +1478,7 @@
char name[32];
snprintf(name, sizeof(name), "bts%u-trx%u-ts%u-ss%u",
lchan->ts->trx->bts->nr,
lchan->ts->trx->nr, lchan->ts->nr, lchan->nr);
+ LOGP(DL1C, LOGL_NOTICE, "allocating DTX FSM for chan_nr=%d\n",
chan_nr);
lchan->tch.dtx.dl_amr_fsm = osmo_fsm_inst_alloc(&dtx_dl_amr_fsm,
tall_bts_ctx,
lchan,
--
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Gerrit-Project: osmo-bts
Gerrit-Branch: master
Gerrit-MessageType: newchange
Gerrit-Change-Id: I7bff00b8cf41dc1b0e6e668173bebce23be0d253
Gerrit-Change-Number: 10415
Gerrit-PatchSet: 1
Gerrit-Owner: Stefan Sperling <ssperl...@sysmocom.de>
