AAL type 1 for real-time video transmission over ATM networks

This article describes the design and implementation of an ATM Adaptation Layer (AAL) type 1 transceiver for the transmission of Constant Bit Rate (CBR) signals over ATM networks. The functions of the AAL satisfy the ITU-T Recommendations I.362 and I.363. It is mainly responsible for the Segmentation and Reassembly (SAR) of user information, smoothing the variable cell delay (jitter), detecting lost and missequenced cells and recovering the source clock at the receiver side. The hardware implementation is based on FPGAs. The clock recovery is based on the FIFO filling level observation method.