Digital video broadcasting
Matthew C. Valenti, Shi Cheng, Rohit Iyer Seshadri · Electronics & Communications Engineering Journal · 1997
standardizing digital television services. Its initial standard for satellite delivery of digital television, dubbed DVB-S, used a concatenation of an outer (204,188) byte shortened Reed Solomon code and an inner constraint length 7, variable rate (r ranges from 1/2 to 7/8) convolutional code [1]. The same infrastructure used to deliver television via satellite can also be used to deliver Internet and data services to the subscriber. Internet over DVB-S is a natural competitor against cable modem and DSL technology, and its universal coverage allows even the most remote areas to be served. Because DVB-S only provides a downlink, an uplink is also needed to enable interactive applications such as web browsing. The uplink and downlink need not be symmetric, since many Internet services require a faster downlink. One alternative for the uplink is to use a telephone modem, but this does not allow for always-on service, has modest data rates, and can be costly in remote areas. A more attractive alternative is for the subscriber equipment to transmit an uplink signal back to the satellite over the same antenna used