diff --git a/openair1/PHY/MODULATION/nr_modulation.c b/openair1/PHY/MODULATION/nr_modulation.c
index 9ad12c1a96..764b02065f 100644
--- a/openair1/PHY/MODULATION/nr_modulation.c
+++ b/openair1/PHY/MODULATION/nr_modulation.c
@@ -150,6 +150,7 @@ void nr_modulation(uint32_t *in,
   default:
     break;
   }
+  AssertFatal(false,"Invalid or unsupported modulation order %d\n",mod_order);
 
 }