diff --git a/OpenAPI/TS28541_NrNrm.yaml b/OpenAPI/TS28541_NrNrm.yaml
index e8c99cf01509665a48f93ed4294107e3b563a52e..0a4decc8906d23a246b6682f4d94f8606e5d5b45 100755
--- a/OpenAPI/TS28541_NrNrm.yaml
+++ b/OpenAPI/TS28541_NrNrm.yaml
@@ -168,10 +168,19 @@ components:
           type: integer
           minimum: 0
           maximum: 100
-        numberOfPreamblesSent:
-          type: integer
-          minimum: 0
-          maximum: 200
+        maxNumberOfPreamblesSent:
+          enum:
+            - n3
+            - n4
+            - n5
+            - n6
+            - n7
+            - n8
+            - n10
+            - n20
+            - n50
+            - n100
+            - n200
 
     UeAccDelayProbabilityDist:
       type: array