Digital Advanced TV For Broadband Networks

Abstract

The Broadband Integrated Services Digital Network (BISDN) is a new concept for exchange area communications. Based on lightwave technology, high -speed circuit and packet switching, and intelligent networking, BISDN will integrate services such as voice, data, video, LAN (Local Area Network), and MAN (Metropolitan Area Network) under the same umbrella as POTS (Plain Old Telephone Service). Among various components of the BISDN, the cell -based ATM (Asynchronous Transfer Mode) multiplexing technique is a powerful vehicle for providing integrated services effectively. Among various services envisaged for BISDN, high -quality video may be the most attractive new service for the majority of residential customers. Therefore, the digital coding of high -quality video signals in a form suitable for transmission through the proposed BISDN network is of great interest and importance. The coding of ATV (advanced television) for digital transmission is of particular importance since it may represent the most viable means for avoiding transmission impairments and delivering very high image quality. The target rate for the coding of the ATV signal is the currently proposed CCITT H4 rate of roughly 135 Mbps, which is the BISDN payload of the SONET channel. In this paper, we review the structure of the BISDN and effective digital coding of ATV at about 135 Mbps. We also address issues related to transmission of compressed ATV over the cell -based ATM networks. BROADBAND DIGITAL NETWORKSAdvances in lightwave technology and high -speed circuits can realize very wide bandwidths in a single fiber. Using this high capacity, it is possible to combine data representing various services and transmit them on a single fiber. The Broadband Integrated Services Digital Network (BISDN) is intended to be the unified long -term solution to the telecommunication needs of the information era that will efficiently integrate the provision of a wide variety of services. Among these are services based on the transport of voice, data, and video, as well as LAN (Local Area Network), and MAN (Metropolitan Area Network) interconnects. BISDN will be implemented by connecting one or more single -mode fibers to each customer site. It is crucial that the overall system be designed with the ability to evolve as network technology progresses and be capable of providing increasingly sophisticated services.Currently one of the most attractive physical (and logical) optical fiber distribution architectures for BISDN appears to be the final star topology. A block diagram of the system architecture is shown in Figure 1. In this architecture, a remote connecting point, which may be at the curbside or at a more elaborate Remote Electronics (RE) site, is used to concentrate traffic from residential and small business customers and also to distribute traffic to them. The RE traffic is then connected, along with two -way traffic from large business customers, to Central Offices (CO). A principal motivation for choosing a dedicated fiber (or pair of fibers) for each cus...