Support puncturing scheme selection for EGPRS DL
Adds support to find the puncturing scheme for retransmission
with MCS change, retransmission with no MCS change, transmission
case. Puncturing scheme selection for retransmission case with
MCS change is aligned with TS 44.060 9.3.2.1. Puncturing scheme
selection for retransmission without MCS change, fresh transmission
is aligned with TS 44.060 10.4.8a.3.1, 10.4.8a.2.1, 10.4.8a.1.1
diff --git a/src/rlc.cpp b/src/rlc.cpp
index 6ea1597..6770043 100644
--- a/src/rlc.cpp
+++ b/src/rlc.cpp
@@ -399,3 +399,77 @@
default: ;
}
}
+
+/*
+ * Finds the PS value for retransmission with MCS change,
+ * retransmission with no MCS change, fresh transmission cases.
+ * The return value shall be used for current transmission only
+ * 44.060 9.3.2.1 defines the PS selection for MCS change case
+ * cs_current is the output of MCS selection algorithm for retx
+ * cs is coding scheme of previous transmission of RLC data block
+ */
+enum egprs_puncturing_values gprs_get_punct_scheme(
+ enum egprs_puncturing_values punct,
+ const GprsCodingScheme &cs,
+ const GprsCodingScheme &cs_current)
+{
+ /* TS 44.060 9.3.2.1.1 */
+ if ((GprsCodingScheme::Scheme(cs) == GprsCodingScheme::MCS9) &&
+ (GprsCodingScheme::Scheme(cs_current) == GprsCodingScheme::MCS6)) {
+ if ((punct == EGPRS_PS_1) || (punct == EGPRS_PS_3))
+ return EGPRS_PS_1;
+ else if (punct == EGPRS_PS_2)
+ return EGPRS_PS_2;
+ } else if ((GprsCodingScheme::Scheme(cs) == GprsCodingScheme::MCS6) &&
+ (GprsCodingScheme::Scheme(cs_current) == GprsCodingScheme::MCS9)) {
+ if (punct == EGPRS_PS_1)
+ return EGPRS_PS_3;
+ else if (punct == EGPRS_PS_2)
+ return EGPRS_PS_2;
+ } else if ((GprsCodingScheme::Scheme(cs) == GprsCodingScheme::MCS7) &&
+ (GprsCodingScheme::Scheme(cs_current) == GprsCodingScheme::MCS5))
+ return EGPRS_PS_1;
+ else if ((GprsCodingScheme::Scheme(cs) == GprsCodingScheme::MCS5) &&
+ (GprsCodingScheme::Scheme(cs_current) == GprsCodingScheme::MCS7))
+ return EGPRS_PS_2;
+ else if (cs != cs_current)
+ return EGPRS_PS_1;
+ /* TS 44.060 9.3.2.1.1 ends here */
+ /*
+ * Below else will handle fresh transmission, retransmission with no
+ * MCS change case
+ */
+ else
+ return punct;
+ return EGPRS_PS_INVALID;
+}
+
+/*
+ * This function calculates puncturing scheme for retransmission of a RLC
+ * block with same MCS. The computed value shall be used for next transmission
+ * of the same RLC block
+ * TS 44.060 10.4.8a.3.1, 10.4.8a.2.1, 10.4.8a.1.1
+ */
+void gprs_update_punct_scheme(enum egprs_puncturing_values *punct,
+ const GprsCodingScheme &cs)
+{
+ switch (GprsCodingScheme::Scheme(cs)) {
+ case GprsCodingScheme::MCS1 :
+ case GprsCodingScheme::MCS2 :
+ case GprsCodingScheme::MCS5 :
+ case GprsCodingScheme::MCS6 :
+ *punct = ((enum egprs_puncturing_values)((*punct + 1) %
+ EGPRS_MAX_PS_NUM_2));
+ break;
+ case GprsCodingScheme::MCS3 :
+ case GprsCodingScheme::MCS4 :
+ case GprsCodingScheme::MCS7 :
+ case GprsCodingScheme::MCS8 :
+ case GprsCodingScheme::MCS9 :
+ *punct = ((enum egprs_puncturing_values)((*punct + 1) %
+ EGPRS_MAX_PS_NUM_3));
+ break;
+ default:
+ break;
+ }
+}