In wireless networks where the goal is to support a large number of VOIP based cellular calls, large overhead headers in RTP voice packets are not acceptable. In wireless networks where multiple base stations are deployed, handsets may handoff from one base station to the other while in a voice call creating a large overhead. This disclosure describes an efficient way to extend a header compression algorithm and lower the overhead when the handset is in a voice call and hands off from one base station to another.