Methods of calculating burst error due to hierarchical out-of-frame events

In a digital hierarchy with independent frame phases, when the frame synchronization is lost in some level, an out-of-frame event is propagated to the hierarchy and burst errors are generated. In this paper, we study methods for calculating the duration of the burst error that accompanies a hierarchical out-of-frame event. First, we discuss hierarchical reframing for a justification system, which is widely used as a digital hierarchy, and outline the characteristics of the parameters needed in the calculation. Next, we study two calculation methods, the detailed method and the approximate method. The detailed method accurately determines the burst error duration, and complex reframing is carefully reflected in the calculation. On the other hand, the approximate method simplifies the calculation by assuming relatively simple reframing. Finally, we demonstrate through numerical examples that the burst error durations agree relatively well between the two calculation methods. As a result, we expect to be able to apply the approximate method. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 85(12): 15–28, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10040