IP over DVB-S2

  • IP datagrams or other network level packets can be transmitted over DVB-S2 satellite links using the Generic Stream Encapsulation (GSE).


    DVB-S2X is implementing the most efficient modulation and coding techniques, very close to the Shannon limit. QO-100 shall be a perfect ground for experimenting with new IP over DVB-S2 packet oriented communication protocols. This could also include Voice-over-IP and other things. Symbol-rates could be as low as 66kS or perhaps even less for data only...


    IP Encapsulation will allow to send IP datagrams even together with a DATV signal.

    It shall be possible to setup a ground station or Hub with connection to the amateur radio "hamnet", supporting several lower speed uplinks. This could be installed for example at the AMSAT HQ in Bochum where we already have HamNet access.


    We are looking for an open discussion and supporters, i.e. software developers.

    Peter Gülzow | DB2OS | AMSAT-DL member since 1983 | JO42VG

  • DB2OS

    Approved the thread.
  • DB2OS Everything is possible but your own WB tpx operating rules speak explicitly about 'TV' (DATV, DVB-S2 + bandplan etc). TV has a visual component, i.e. its intention is to transmit pictures/movies etc where sound and/or data component are 'by-catches'. If we leave that perception all (WB) experiments -regardless of their mode of transmission- are 'allowed' on the WB tpx.

  • hmm.. just checked the WB op rules and I cannot find anything that says that the DVB-S2 stream needs to be video. So even by the rules, IP encapsulation is totally fine and if not, we can/should clarify on this because in my personal opinion IP-encapsulation in DVB-S2 is much more suitable for sat ops than any of the HF modes (Winlink, etc.) on the NB.


    Just beware that with IP encapsulation the traffic still needs to be transparent according to hamradio rules. No encrypted traffic (no https and no ssh for example).


    And don't forget Wednesday:

    On Wednesdays (UTC time), experimenters are encouraged to try other modes – perhaps 6 MS using the whole transponder for brief (less than 10 minute) periods. It is essential that users to announce their plans on the chat room page, and to always monitor it.


  • Clear explanation, but then the term 'DATV' , 'TV' , 'ATV' needs to be replaced with 'DVB-S2' (to name a suggestion). In the professional world (like SNG (satellite news gathering) several audio channels (digital, VoIP) are normal e.g. to have communication with the studio control room or camera men.

  • Sorry to be precise.. but in the WB guidelines, neither DATV nor ATV nor TV are mentioned. However, DVB-S2 is:

    Transmissions should use DVB-S2 where possible.


    So I think (although I agree it could be clearer) IP via DVB-S2 is fully in compliance with the WB operating rules.

  • I am absolutely ok with everybody asking before actually doing anything.. it's a bit like RX before TX. :)


    Experimenters Wednesday has a long history on the former AMSAT satellites and we would like to keep it that way. Just announce what you are doing in the forum and WB chat and keep trials to a reasonable time span.

  • If you are going to be pedantic like this with respect to if it's called TV or not, I would point out amateurs are not permitted to broadcast so using DVB as a term is unwise. DATV-S2 perhaps or DA-S2?

  • I would point out amateurs are not permitted to broadcast

    I am not sure about that.. I know from G8GTZ and G8GKQ that this is indeed true for the UK. At least in Germany, this is much more relaxed as we have regular and fully official hamradio broadcast programmes ('Rundspruch').

  • Really? That's unusual I think. You Germans are lucky. Anyway, we are not really broadcasters in the usual sense of Sky, RTL, etc.


    Back to the point, I would be interested to try Satellite IP if we have a standard.


    Mike

  • Gentlemen,
    with all respect, we have less bandwidth than stations in die WB-transponder for DATV. If we are starting to do pure data-services, where is the bandwidth for TV? What are the next plans to overcrowd that transponder?

    Right now, there is already a standard for IP over DVB-S2.
    But on the the other hand, we have done data over TV even in the analogue days. Did somebody remember Videotext? In DVB we are just talking about PIDs. If either we are doing SCTP, or MCTP, both are multiplexes.

    Right now, even if we transmit a "simple" TV-channel, we are already talking about PMT,PAT, Video PID and Audio PID. Did anybody recognize, that the program-name is our callsign? In fact, we are sending a simple EPG as well.

    If there is the need for a "data-channel", just decrease the symbol-rate for video in the beacon and use f.e. 500kSym/s of that stream to multiplex IP-over-DVB-S2 into an new PID.

    What are we loosing, when implementing data-services as a new PID into the beacon? Nothing, except a loop-video, we've seen for the past month with full bandwidth.

    Just my 2 cents.

  • Not in an amateur capacity, I have done IP-over DVB-S using a C-band transponder in Kampala, Abuja and a few other places.
    This was quite a common way to get bandwith to Africa before fiber infra existed. As Peter suggests, it has a pretty good bit/hz radio and DVB-S2 is probably better. In my case, this was for downstream only; upstream was using common BPSK if memory serves.


    The receivers were small PC's with a "DVB-S PCI card" running Linux. I'm not sure about the encapsulation used, too busy making the link work and dealing with other issues and the comfort of doing work in tropical conditions.


    Setting up an uplink on a commercial transponder is quite something different than what we are used to on QO100. You don't "just adjust the power"; you call the operator, put your signal on a special test frequency, have the signal optimized (maximal polarization isolation; optimal skew adjustments are a requirement!), have it adjusted for RF signal levels and when all is OK you would be told to move to your allocated frequency. If you would turn up your RF power by as much as 3dB afterwards you will find your transponder notched and you need to call the operator again.


    C-band is much more popular because it is less affected by the weather (if you've been in an equator rainstorm, you will understand).


    Latency, of course, is an issue. Using decent protocol stacks (FreeBSD) made quite the difference.


    I'm currently not set up for the WB transponder but learned *a lot* making this work. If you have the cycles, do try, if must be on a Wednesday..

  • As a side note, the EUMETCAST service uses DVB-S2 these days to distribute meteo products via IP streams / commercial broadcast sats. This is the METEOSAT/MSG2 data. Beautiful if you ask me, and free for non-commercial/amateur use.


    I used to receive it from a sat 5E (?? IIRC, it is a while ago and I forgot the sats name).

    In those days it was still DVB-S (non-S2 in other words). I currently do not have a PCI DVB-S2 card so I cannot receive


    Wilko