TIMING AND SYNCHRONIZATION TECHNIQUE FOR ATM SYSTEM

摘要

A system and method for regulating cell transfer timing and for reestablishing resynchronization in a packet switched telecommunications system is described. One or more marker cells, called Empty Cell Position (ECP) patterns, are placed between and amongst a sequence of data cells (figure 5). Each ECP pattern comprises a bit sequence that is readily distinguishable from a data cell but having the ability to substitute for a standard data cell in an outgoing transmission time slot. This permits control of the relative transmission times of each data cell of the sequence. The data cells and ECP patterns are placed in an elastic buffer such as a FIFO to permit cell generation to be made relatively independent of cell transmission. This method and system additionally permits a cell transmitter to reestablish synchronization every time it detects an ECP pattern. Different ECP patterns can be used to represent varying inter-cell intervals. A cell generator places data cells and ECP patterns in a buffer. A cell transmitter retrieves the data cells and ECP patterns from the buffer and transmits the data cells (705) after a time delay that depends on the number and contents of the ECP patterns immediately preceding that data cell (figure 7).