HEC identifying in SDH-ATM interface circuit

While transmitting the ATM (asynchronous transfer mode) cells using the SDH (synchronous digital hierarchy)-based physical layer, we have to identify the cell boundaries. Either using the H4 byte of the VC4-POH (virtual container 4-path overhead) or HEC (header error control) byte checking method can be used. In this paper, two circuit architectures based on 0.8 /spl mu/m CMOS technique are presented using HEC method to identify the ATM cell boundaries.