Monday, June 13, 2011
Use of FPGA-based channel bonding for HDTV DSL
In almost every day new applications for sound and video push the bandwidth requirements for DSL networks, while Telecom carriers in the United States and around the world are directed to the delivery of digital and high-definition television (HDTV) for consumers. To achieve the delivery of such services without deploying new fibre everywhere, carriers should leverage existing copper deployments already in the ground.
Most DSL lines offer sufficient capacity for the provision of standard television (band). Most programs are available from streaming servers at bitrates of around 750 kbps, with some programs, providing 1.5 Mbps bandwidth. However, to allow streaming of high quality HDTV and multiple channels simultaneously, the House must have a range of at least 16 Mbps. Although the new DSL from ADSL2 and VDSL can offer these speeds, they may not offer high enough on longer distances on a typical DSL line. Therefore, HDTV programmes may be supplied only to households near the DSLAM. Those which are located further away to receive only the lower quality bar programming.
In order to ensure that DSL remains the preferred place for end users, service providers are seeking new ways to improve the effectiveness of DSL networks. While the VDSL and ADSL2 provides better performance, restrictions in the distance is difficult to overcome. Another scenario is to DSLAMs closer to end-users, but often are the prohibitive costs associated with installation of new equipment in the network.
Channel bonding in DSLAMs and DSL modems
DSL channel bonding provides the ideal combination of features: higher bandwidth of all users and the possibility of extending the distance which can be reached at a certain bandwidth. Instead of using a single copper, DSL bonding distributes traffic over a set of copper wires. To achieve the effective speed of 12 Mbps DSL line, three 4-Mbps to be bundled with channel bonding processor in each of the ends of lines. In most copper networks subscribers already are linked by several cables so that no new cables must be installed to provide channel bonding service, as shown in Figure 1.
Download pdf, Using FPGA-Based channel bonding for HDTV over DSL
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