DVB-S2 is something you don't hear much about in this forum, and I applaud DirecTV for taking the leap and adopting it (the "other" company isn't using it). The article mentioned a 30% performance improvement over DVB-S, and this is true. What it means to us is more HD channels and less rain fade at Ka band. DVB-S2 allows MPEG-4 compression for HD and pilots to recover the signal during high noise conditions (rain fade).
So far DirecTV is using DVB-S2 for some of the locals. The problem with DVB-S2 is it's not compatible with the older DVB-S receivers, so they have to replace all of the older receivers before they can implement DVB-S2 across the board. This is the main reason Dish has so far chosen to not use DVB-S2.
Don't know. When I was at the NAB show in April I walked over to the Echostar booth and asked if Dish had any plans to implement DVB-S2. The person I spoke to said no, because it was too expensive to change out the existing receivers.
The pilots used with DVB-S2 can not eliminate rain fade, only help. Ka-Band is more susceptible to rain fade than Ku-Band, so the DVB-S2 pilots help keep Ka-Band on par with Ku. But they can't eliminate it completely.
Pilots, or more correctly pilot symbols, consist of additional information which the receiver uses to help lock onto the carrier. That's a very simplified description.
The pilots are inserted into the DVB-S2 frame structure along with the data (video and audio information).
DVB-S2 allows the use of higher order modulation compared to DVB-S which allowed only QPSK. These higher order modulations (8PSK, 16APSK and 32APSK) require LNBs with high stability and low phase noise. In short, DVB-S2 can not get away with the cheaper LNBs now used by DVB-S. These pilot symbols give the receiver something to lock onto.
Another example is during rain fade when the C/N drops (signal falls into the noise). The pilots help the receiver hang in there a bit longer before losing lock.
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