Subsets of the STM-1 frame-alignment signal: a monitoring analysis

A novel approach to frame-alignment monitoring considers splitting the frame-alignment signal into its independent subsets, making the evaluation of the out-of-frame detection time within the overlap zone quite complex. The paper proposes a simplified model for this evaluation. An STM-1 framing signal is used as an illustrative example and it is pointed out that its repetitive structure is not suitable for splitting. Framing signals optimised specifically for splitting into subsets are introduced.