Design of Transmission and Multiplexing Systems for Broadband Packet Networks

Dynamic time division multiplexing (DTDM) is a flexible network transport technique capable of handling both continuous and bursty traffic effectively. By employing three different multiplexing architectures in the network, DTDM permits graceful evolution of the existing circuit switching network into a flexible broadband packet communication network supporting integrated voice, data, and video traffic. The first multiplexing stage uses a packet assembler to multiplex different broadband services into a common DTDM-format serial bit stream. The second multiplexing stage uses a statistical packet multiplexer to concentrate network traffic for more efficient use of transmission facilities. A novel architecture for a multiple-input multiple-output statistical packet multiplexer was designed so that the total traffic load of the multiplexer can be evenly distributed among the output lines and the service priority of each input line can be rearranged dynamically. The third multiplexing stage uses a synchronous time division multiplexer for highspeed point-to-point transparent transmission. The multiplexer uses a simple tributary synchronization scheme based on positive and negative block justification, which combines the concept of controlled-slip and bit-stuffing techniques while maintaining information integrity. A generic CMOS LSI chip has been designed for use in the above three-stage multiplexing system.