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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
This commit is contained in:
Stefan Sperling 2018-08-09 20:14:19 +02:00 committed by Harald Welte
parent 0ab50934d5
commit 9bffa87c11
1 changed files with 64 additions and 13 deletions
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77
src/common/l1sap.c
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@ -666,6 +666,31 @@ static int lchan_pdtch_ph_rts_ind_loop(struct gsm_lchan *lchan,
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, struct gsm_time *g_time) {
/* 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 };
/* And the subset of those frames which corresponds to a TCH/F block boundary,
* which is the level at which L1SAP operates: */
const int tchf_required_block_fn_dtx[] = { 52, 56 };
int i;
for (i = 0; i < ARRAY_SIZE(tchf_required_block_fn_dtx); i++) {
if (fn % 104 == tchf_required_block_fn_dtx[i])
return true;
}
/* We should only see block-level frame numbers here. Log a warning otherwise. */
for (i = 0; i < ARRAY_SIZE(tchf_required_fn_dtx); i++) {
if (fn % 104 == tchf_required_fn_dtx[i])
LOGPGT(DL1P, LOGL_NOTICE, g_time,
"Unexpected TCH/F frame number received in RTS.IND "
"(not at TCH/F block boundary): %u (mod 104: %u)\n", fn, fn % 104);
}
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)
@ -725,14 +750,18 @@ static int l1sap_ph_rts_ind(struct gsm_bts_trx *trx,
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 */
@ -752,20 +781,39 @@ static int l1sap_ph_rts_ind(struct gsm_bts_trx *trx,
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 (dtxd_facch) {
/*
* 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, &g_time)) {
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); /* XXX is this needed? */
}
} 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 */
@ -786,8 +834,10 @@ static int l1sap_ph_rts_ind(struct gsm_bts_trx *trx,
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);
@ -1436,6 +1486,7 @@ int l1sap_chan_act(struct gsm_bts_trx *trx, uint8_t chan_nr, struct tlv_parsed *
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,