DVB-SH
DVB-SH (from English Digital Video Broadcasting - satellite services to handheld devices , in German digital video broadcasting via satellite for handheld devices ) is a transmission standard with which digital radio programs can be received via small and / or mobile devices ( mobile television ). DVB-SH is based on the sister standard DVB-H and ETSI SDR . A similar technology is used at S-DMB . The system consists of geostationary satellites; in metropolitan areas these are still supported by repeaters .
This is a new broadcast standard for processing satellite signals for mobile devices. As with normal satellite reception, there must be a direct “view” of the satellite. This makes reception more difficult in buildings, but DVB-H transmitters are available for this in the metropolitan areas. Satellite reception covers rural regions.
technology
DVB-SH uses frequencies in the S-band (channels between 2170 MHz and 2200 MHz). In addition to error correction called Turbo Coding for Forward Error Correction, the transmission technology also includes the option of involving terrestrial networks in satellite transmissions via repeaters . Additional terrestrial transmission systems in DVB-SH mode are intended to close any gaps in coverage.
Current status
In 2006, ESA commissioned the first S-band repeater for satellites as part of the ARTES-4 program.
According to a report by Deutschlandfunk, a satellite has already been ordered from Alcatel, which will go into operation at the end of 2009 and which will allow the transmission of around 12 to 20 channels. How many radio programs with z. B. 128 kbps of space on a channel has not yet been officially announced.
The 30 MHz bandwidth (2170–2200 MHz) corresponds almost exactly to that of a single DVB-S / DVB-S2 transponder from TV satellites in the Ku band . At 30 Mbit / s - if the FEC rate (error protection rate) is identical to the one used for reception via a parabolic antenna - it can be assumed that there are around 234 possible radio programs at 128 kbps each, which with current compression methods would far exceed VHF quality. If TV programs are actually offered, however, the number of radio programs is also drastically reduced, or alternatively it has to be broadcast with an extremely low TV resolution of 320 × 240 or even fewer pixels and a low frame rate that is expressed in jerks in order to achieve bandwidth to save.
Eutelsat and Astra will position the required satellites at 10 ° East at the end of 2008. Starting in 2009, together with terrestrial repeaters, it will distribute the radio, video and data service for mobile devices (including inside buildings) and receivers in vehicles, which are sold under the name Solaris.
On October 6, 2009, the first test program in the DVB-SH standard in Germany started at the University of Erlangen-Nuremberg .
Web links
swell
- ^ DVB Project
- ↑ DVB-SH for rural regions ( Memento of the original from July 17, 2007 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ DVB-SH Presentation DVB-SH Paris of Alcatel March 21, 2007 ( Memento of the original from October 30, 2007 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Current: 1. S-Band Repeater ( Memento of the original from July 17, 2007 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ heise online, April 2, 2008, message from SES Astra, last paragraph
- ↑ Chair of Information Technology, University of Erlangen-Nuremberg ( Memento of the original from May 20, 2010 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.
