diff --git a/src/csn1.cpp b/src/csn1.cpp
index 6203a44..9ddb9c1 100644
--- a/src/csn1.cpp
+++ b/src/csn1.cpp
@@ -190,6 +190,7 @@
 
       case CSN_NULL:
       { /* Empty member! */
+        bit_offset += pDescr->i;
         pDescr++;
         break;
       }
@@ -631,6 +632,7 @@
 
           case CSN_NULL:
           { /* Empty member! */
+            bit_offset += pDescr->i;
             pDescr++;
             break;
           }
diff --git a/src/csn1.h b/src/csn1.h
index 1015e69..39e6625 100644
--- a/src/csn1.h
+++ b/src/csn1.h
@@ -592,8 +592,8 @@
 #define M_PADDING_BITS(_STRUCT)\
         {CSN_PADDING_BITS, 0, {0}, 0, TRUE, "Padding", {(StreamSerializeFcn_t)0}}
 
-#define M_NULL(_STRUCT, _MEMBER)\
-        {CSN_NULL, 0, {0}, offsetof(_STRUCT, _MEMBER), FALSE, #_MEMBER, {(StreamSerializeFcn_t)0}}
+#define M_NULL(_STRUCT, _MEMBER, _SKIP_BITS)\
+        {CSN_NULL, _SKIP_BITS, {0}, offsetof(_STRUCT, _MEMBER), FALSE, #_MEMBER, {(StreamSerializeFcn_t)0}}
 
 #define M_THIS_EXIST(_STRUCT)\
         {CSN_EXIST, 0, {0}, offsetof(_STRUCT, Exist), FALSE, "Exist", {(StreamSerializeFcn_t)0}}
diff --git a/src/gsm_rlcmac.cpp b/src/gsm_rlcmac.cpp
index 339279c..c1d3b97 100644
--- a/src/gsm_rlcmac.cpp
+++ b/src/gsm_rlcmac.cpp
@@ -605,7 +605,7 @@
 static const
 CSN_ChoiceElement_t SI13_PBCCH_Description_Channel[] =
 {/* this one is used in SI13*/
-  {2, 0x00 , M_NULL(PBCCH_Description_t, u.dummy)},/*Default to BCCH carrier*/
+  {2, 0x00 , M_NULL(PBCCH_Description_t, u.dummy, 0)},/*Default to BCCH carrier*/
   {2, 0x01 , M_UINT(PBCCH_Description_t, u.ARFCN, 10)},
   {1, 0x01 , M_UINT(PBCCH_Description_t, u.MAIO, 6)},
 };
@@ -3064,7 +3064,7 @@
 
 static const
 CSN_DESCR_BEGIN        (Delete_All_Stored_Individual_Priorities_t)
-  M_NULL               (Delete_All_Stored_Individual_Priorities_t, dummy),
+  M_NULL               (Delete_All_Stored_Individual_Priorities_t, dummy, 0),
 CSN_DESCR_END          (Delete_All_Stored_Individual_Priorities_t)
 
 static const