diff --git a/src/gprs_rlcmac_ts_alloc.cpp b/src/gprs_rlcmac_ts_alloc.cpp
index b9d4e41..ec228d1 100644
--- a/src/gprs_rlcmac_ts_alloc.cpp
+++ b/src/gprs_rlcmac_ts_alloc.cpp
@@ -405,13 +405,21 @@
 	Trb = ms_class->rb;
 	Type = ms_class->type;
 
-	/* Tta and Ttb may depend on hopping or frequency change */
-	/* TODO: Set them to 1  */
-	if (Ttb == MS_A || Ttb == MS_B)
+	/* MS_A maps to 0 if frequency hopping is disabled */
+	/* TODO: Set it to 1 if FH is implemented and enabled */
+	if (Ttb == MS_A)
 		Ttb = 0;
-	if (Trb == MS_A || Trb == MS_C)
+	if (Trb == MS_A)
 		Trb = 0;
 
+	/* MS_A and MS_B are 0 iff FH is disabled and there is no Tx/Rx change.
+	 * This is never the case with the current implementation, so 1 will
+	 * always be used. */
+	if (Ttb == MS_B)
+		Ttb = 1;
+	if (Trb == MS_C)
+		Trb = 1;
+
 	LOGP(DRLCMAC, LOGL_DEBUG, "- Rx=%d Tx=%d Sum Rx+Tx=%s  Tta=%s Ttb=%d "
 		" Tra=%d Trb=%d Type=%d\n", ms_class->rx, Tx,
 		(Sum == MS_NA) ? "N/A" : digit[Sum],