SELECTIVE RESYNCHRONIZATION IN A DIGITAL CELLULAR COMMUNICATIONS SYSTEM DURING HANDOVER

摘要

In a ciphered digital cellular communications system a method and apparatus are presented for selective resynchronization of the cipher upon initial channel acquisition or handoff. Where synchronization between the old channel and the new channel exists, the base station indicates along with an ITCD or handover message that no resynchronization is required. Where synchronization between the old channel and the new channel does not exist, the base station provides an indication along with an ITCD or handover message that resynchronization is required and from the content of this message the manner in which resynchronization is to be achieved is further indicated. By providing options for resynchronization security may be optimized or compromised for handover speed depending upon the specific requirements of the base station or the mobile station.