diff --git a/OpenAPI/TS28541_NrNrm.yaml b/OpenAPI/TS28541_NrNrm.yaml
index 17809fbff818e646b603b86696c82cd357718bad..6e3ee78394edc942e3477da0ac6f18204234b671 100755
--- a/OpenAPI/TS28541_NrNrm.yaml
+++ b/OpenAPI/TS28541_NrNrm.yaml
@@ -167,10 +167,19 @@ 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