The present invention provides a priority scheme and a data rate reduction method to increase the reliability of the signaling messages on a shared packet data channel. Signaling messages and packet data received for transmission are stored in a packet data buffer and at least one signaling buffer, respectively. Packet data or signaling messages are transmitted based on the scheduling algorithm assigned priority. The signaling message priorities are adjusted by a weighting factor assigned to the signaling buffer. The signaling message priority may be adjusted by a Quality of Service level. The transmission data rate is adjusted by an offset factor from the highest possible data rate that can be supported to a lower rate to improve reliability. To increase the effective data rate, the signaling message may be concatenated with another signaling message in order to completely fill the signaling message frame.