A method is provided for improving reliability in semi-persistent scheduling activation/reactivation is provided. The method includes a user agent receiving a first data element from an access device specifying at least one first transport block size. The method further includes the user agent deriving a second transport block size based on a second data element received from the access device. The method further includes the user agent comparing the first transport block size with the second transport block size. The method further includes, when the first transport block size differs from the second transport block size, the user agent ignoring the received semi-persistent scheduling activation/reactivation data.