your question is not clear, i’m sorry…
it’s not your job to send a message to the MS, it’s the job of the BTS and BSC 🙂 what you have to do is set the OMC-R parameters so that the minimum TX power of a MS = 28dBm.
The messages, the coding and all that is taken care of by the BSS.
Now, I’m surprised that the minimum TX Power should be equal to 28dBm. Aren’t you mistaking ? It should be MAX power = 28dBm, instead of the usual 33dBm.
The Minimum power should be set as low as possible, in order to give enough room for power control.