Modify DL tbf flow for ARQ-II in EGPRS DL Retx
Modify the DL TBF flow to support ARQ-II EGPRS DL retransmission
Change-Id: I7a845c98f2018795f0f62240f228411b0bc030c7
diff --git a/src/tbf_dl.cpp b/src/tbf_dl.cpp
index 1ca9c4a..07a747a 100644
--- a/src/tbf_dl.cpp
+++ b/src/tbf_dl.cpp
@@ -355,13 +355,12 @@
{
int bsn;
int data_len2, force_data_len = -1;
- GprsCodingScheme cs2;
GprsCodingScheme force_cs;
bsn = m_window.resend_needed();
if (previous_bsn >= 0) {
- force_cs = m_rlc.block(previous_bsn)->cs_last;
+ force_cs = m_rlc.block(previous_bsn)->cs_current_trans;
if (!force_cs.isEgprs())
return -1;
force_data_len = m_rlc.block(previous_bsn)->len;
@@ -375,7 +374,28 @@
m_window.mod_sns(bsn - previous_bsn) > RLC_EGPRS_MAX_BSN_DELTA)
return -1;
- cs2 = m_rlc.block(bsn)->cs_last;
+ if (is_egprs_enabled()) {
+ m_rlc.block(bsn)->cs_current_trans =
+ GprsCodingScheme::get_retx_mcs(
+ m_rlc.block(bsn)->cs_last, ms()->current_cs_dl());
+
+ LOGP(DRLCMACDL, LOGL_DEBUG,
+ "- current_cs_dl(%d) demanded_mcs(%d) cs_trans(%d)\n",
+ m_rlc.block(bsn)->cs_last.to_num(),
+ ms()->current_cs_dl().to_num(),
+ m_rlc.block(bsn)->cs_current_trans.to_num());
+
+ /* TODO: Need to remove this check when MCS-8 -> MCS-6
+ * transistion is handled.
+ * Refer commit be881c028fc4da00c4046ecd9296727975c206a3
+ */
+ if (m_rlc.block(bsn)->cs_last == GprsCodingScheme::MCS8)
+ m_rlc.block(bsn)->cs_current_trans =
+ GprsCodingScheme::MCS8;
+ } else
+ m_rlc.block(bsn)->cs_current_trans =
+ m_rlc.block(bsn)->cs_last;
+
data_len2 = m_rlc.block(bsn)->len;
if (force_data_len > 0 && force_data_len != data_len2)
return -1;
@@ -398,13 +418,14 @@
if (restart_bsn_cycle())
return take_next_bsn(fn, previous_bsn, may_combine);
} else if (have_data()) {
+ GprsCodingScheme new_cs;
/* New blocks may be send */
- cs2 = force_cs ? force_cs : current_cs();
+ new_cs = force_cs ? force_cs : current_cs();
LOGP(DRLCMACDL, LOGL_DEBUG,
"- Sending new block at BSN %d, CS=%s\n",
- m_window.v_s(), cs2.name());
+ m_window.v_s(), new_cs.name());
- bsn = create_new_bsn(fn, cs2);
+ bsn = create_new_bsn(fn, new_cs);
} else if (!m_window.window_empty()) {
LOGP(DRLCMACDL, LOGL_DEBUG, "- Restarting at BSN %d, "
"because all blocks have been transmitted (FLOW).\n",
@@ -418,7 +439,7 @@
"- Sending new dummy block at BSN %d, CS=%s\n",
m_window.v_s(), current_cs().name());
bsn = create_new_bsn(fn, current_cs());
- /* Don't send a second block, so don't set cs2 */
+ /* Don't send a second block, so don't set cs_current_trans */
}
if (bsn < 0) {
@@ -429,7 +450,7 @@
bts->rlc_resent();
}
- *may_combine = cs2.numDataBlocks() > 1;
+ *may_combine = m_rlc.block(bsn)->cs_current_trans.numDataBlocks() > 1;
return bsn;
}
@@ -501,6 +522,7 @@
rlc_data = m_rlc.block(bsn);
data = rlc_data->prepare(block_data_len);
rlc_data->cs_last = cs;
+ rlc_data->cs_current_trans = cs;
rlc_data->len = block_data_len;
rdbi = &(rlc_data->block_info);
@@ -590,7 +612,6 @@
bool is_final = false;
gprs_rlc_data_info rlc;
GprsCodingScheme cs;
- GprsCodingScheme cs_current_trans;
int bsns[ARRAY_SIZE(rlc.block_info)];
unsigned num_bsns;
enum egprs_puncturing_values punct[ARRAY_SIZE(rlc.block_info)];
@@ -604,7 +625,7 @@
* be put into the data area, even if the resulting CS is higher than
* the current limit.
*/
- cs = m_rlc.block(index)->cs_last;
+ cs = m_rlc.block(index)->cs_current_trans;
bsns[0] = index;
num_bsns = 1;
@@ -616,6 +637,11 @@
if (num_bsns == 1) {
/* TODO: remove the conditional when MCS-6 padding isn't
* failing to be decoded by MEs anymore */
+ /* TODO: support of MCS-8 -> MCS-6 transition should be
+ * handled
+ * Refer commit be881c028fc4da00c4046ecd9296727975c206a3
+ * dated 2016-02-07 23:45:40 (UTC)
+ */
if (cs != GprsCodingScheme(GprsCodingScheme::MCS8))
cs.decToSingleBlock(&need_padding);
}
@@ -650,18 +676,14 @@
else
bsn = bsns[0];
- cs_enc = m_rlc.block(bsn)->cs_last;
-
+ cs_enc = m_rlc.block(bsn)->cs_current_trans;
/* get data and header from current block */
block_data = m_rlc.block(bsn)->block;
- /* TODO: Need to support MCS change during retx */
- cs_current_trans = cs;
-
/* Get current puncturing scheme from block */
punct_scheme = gprs_get_punct_scheme(
m_rlc.block(bsn)->next_ps,
- cs, cs_current_trans);
+ m_rlc.block(bsn)->cs_last, cs);
if (cs.isEgprs()) {
OSMO_ASSERT(punct_scheme >= EGPRS_PS_1);
@@ -685,8 +707,9 @@
* in header type 1
*/
gprs_update_punct_scheme(&m_rlc.block(bsn)->next_ps,
- cs_current_trans);
+ cs);
+ m_rlc.block(bsn)->cs_last = cs;
rdbi->e = block_info->e;
rdbi->cv = block_info->cv;
rdbi->bsn = bsn;