DVB-RCS

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DVB Return Channel are standards that make the DVB TV transmission paths back channel. They are available for the following services:

DVB- RCC = Digital Video Broadcasting - Return Channel Cable
DVB -RCS Digital Video Broadcasting - Return Channel Satellite
DVB- RCT = Digital Video Broadcasting - Return Channel Terrestrial

DVB- RCC

DVB- RCC is in some cable operators already being used to provide Internet access, where there is probably also proprietary processes for the return channel. The TV cable is most likely to provide the Internet. For the rear channels, the frequencies below the VHF band in the cable are specified concretely, the existing TV - channels 2, 3 and 4 ( 48.25 MHz, 55.25 MHz and 62.25 MHz). In cable networks in which at these frequencies either digital ( these channels were usually never used digital) or analog TV programs can be received, the probability of the availability of internet via cable connection is quite large.

DVB-RCS

DVB -RCS is promoted by SES Global since 1999 and was supposed to already in 2003 should be in regular consumer use. In reality, DVB -RCS has been as good as any provider available, but a very interesting technology for Internet connection with low requirements ( among other things because of the huge latency (ping round trip ) of more than 600 ms) and divide very many participants a transponder and thus its max. 38 Mbit / s As currently still common practice for Internet via satellite - - Europe must share the bandwidth of about 38 Mbit / s per transponder with newer satellite so that it is not there but already partly controllable transponder with comparatively tiny footprints. The return channel to reach up to 2 Mbit / s.

Often, the abbreviation " RCS" with " Return Channel System" confused.

DVB- RCS2

2012, a new version of the DVB -RCS standard was adopted. Compared to its predecessor improved error correction and higher modulation schemes (QPSK, 8 -PSK and 16- QAM) are used. The changes are aimed at increased spectral efficiency and thus to a reduction in costs in the operation as well as higher data rates allow.

DVB- RCT

For DVB - RCT was recruited by big marketing hype during the DVB- T launch phase. Of course, can not do DSL or Internet-enabled cable connections unnecessary DVB -T. Only the analog cable TV service is DVB- T digital terrestrial quite well.

To use terrestrially emitted digital TV, DVB -T, for interactive distribution services such as teleshopping, tele-learning and tele-banking, this service is equipped with a feedback channel, the DVB- RCT. The modulation in the feedback channel uses the OFDM multiple access (MA- OFDM) in the same frequency bands, in which the downstream channels transmit the TV signals. The transmission can take place in the radio cells of up to 65 km in diameter, and the multi- kbit / s DVB - RCT can also transmit power peaks with several thousand transactions per second. The transmit power for the reverse channel, which is applied by the user terminal or from the set-top box, is 0.5 W.

Also, there is no return channel frequencies for DVB- RCT.

Other methods

Rather, the return channel via GPRS, UMTS or only via SMS voting, competitions, could be realized, etc. available.

There are building on satellite receivers (DVB -S ) is already a proprietary product, Astras Blucom in which the phone is connected via Bluetooth and displays additional information. The mobile phone has next to the disadvantage of too small displays but the advantage that it also provides a back channel is available, which is implemented by SMS or GPRS in the concrete product and causes corresponding fees, which the suitability is restricted to certain services with low reaction volume such as voting and competitions.

Even MHP - based solutions with ( any, DVB -based ) feedback channels are possible.

Technical information about frequencies, etc.

Overview: Technical information ( Kathrein )
Channel allocation in the German cable network ( PDF)
DVB -RCS in use - Europe, Middle East and Africa ( Internet Access, VPN, VoIP)

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