for digital video broadcast over satellites, defined by ETSI and ratified in 2005. It has improved quality over DVB-S and allows for coded video in H.264 (AVC) or VC-1 bitstreams. DVB-C (cable TV)-DVB-C is an open standard for digital video transmis- sion over cable that was defined by ETSI and ratified in 1994. DVB-T (terrestrial TV)-DVB-T, an open standard defined by ETSI and ratified in 1997, is used as the de facto standard for terrestrial TV broad- casts in many nations, particularly those in Europe. It supports only MPEG-2 compression. DVB-H (terrestrial TV for handhelds)-The DVB-H standard is an adapta- tion of DVB optimized for mobile handheld devices. It is widely used in Europe and is starting to see adoption in North America. These four distribution systems vary in their modulation schemes, based on the technical constraints associated with the different operating environments. DVB-T and DVB-H use Coded Orthogonal Frequency Division Multiplexing (COFDM), DVB-S uses Quadrature Phase-Shift Keying (QPSK), and DVB-C uses QAM, espe- cially 64-QAM. (Modulation schemes are covered in Chapter 5.) The DVB Project has also designed an open middleware system for DTV, called the DVB-Multimedia Home Platform (DVB-MHP, www.mhp.org), which is being used to support interactive applications in many countries. DVB-MHP enables the reception and execution of interactive, Java-based applications on a TV set, includ- ing applications such as e-mail, SMS, information services, shopping, and games. Although the European Commission has not mandated EU-wide standards for interactive DTV middleware, there is clear support for the continued development of DVB-MHP in the commitment to continue to promote and support open and interoperable standards and to monitor the use of proprietary technologies. As of mid-2005, the largest deployments of DVB-MHP were in Italy (DVB-T) and Korea (DVB-S), with other small deployments or trials taking place in Australia, Finland, Chapter 10 Next-Generation Networks Germany, and Spain. In the Unite