Abstract: To implement the call connection protocol of UMTS core network, a timer design was proposed by the way of software, developed and researched in the environment of WinCE real-time embedded system. Based on relative time algorithm proposed, the timer program, which data structure is constructed by single linked list and relative time item,creates a single time thread and insertion/deletion functions to realize the multiple-timer logic regulated by UMTS protocol. In the embedded system programming, we applied mutex method to implement the synchronization in communicalion between the timer thread and insertion/deletion functions, and adopted heap management method to realize the dynamic allocation and release of memory. The paper discussed the technique and the structure of the plan with key code and analysed the relative WinCE mechanisms and UMTS protocols. Experiments prove that the design, which has the qualities of low hardware occupation and high program efficiency, with good real time ability, is suitable for timer programming in communication protocols based on embedded system.

Key words: Timer,Link queue,Relative time,Core network,WinCE