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I'm working on a project that would require up to near time (<=5mins) of packet base communication over Long Distances of upwards to 80 Gm. Obviously the base station would have to be scaled for this but what would be the best protocol in this use case?

UPDATE

Thanks to everyone whom commented. We are initial looking to use a point-to-point communications medium over an unlicensed band however do realize the limitations of 2.4-5Ghz bands can cause for long distance communications. Hence why we're reaching out.

  • Would love to see a good answer to this. Are not these long range things always circularly polarized? – C. Towne Springer Jan 07 '14 at 07:23
  • Apart from protocol per se, have a look at forward error correcting codes. These effectively have enough redundancy that for a code that can correct N errors, any N errors do not move the resulting code onto a word that could have been caused by N errors from another valid word. Trivial simplistic example: 1 = 11111, 0 = 00000. Any 2 bits change in 11111 cannot be a code you'd get from 2 bits changed in 00000 so this has 2 bots of FEC. Obviously "there's a bit more to it than that. – Russell McMahon Jan 07 '14 at 07:49
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    The phrase " ... up to near time (<=3mins) of packet base communication ..." does not convey (to me) exactly what you mean. I think I may understand exactly what you mean BUT if I'm uncertain then there is a large crowd of others with no clue at all who will close your question, alas. A little more explanation would not go astray. Data rate, data volume. ... – Russell McMahon Jan 07 '14 at 07:51
  • More details are needed, is it in a licensed band? unlicensed band? North America? Europe? Asia? One way? Point to point ot point to multipoint? – Lior Bilia Jan 07 '14 at 08:21
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    *"Distances of upwards to 80M km."* - 80 million kilometers? >4 light-minutes? – RedGrittyBrick Jan 07 '14 at 08:46
  • 4.444 light minutes is not "<=3 mins". Are you expecting a "retry" protocol or something with a stack of error correction bits? – Andy aka Jan 07 '14 at 11:18
  • "80M km" is confusing, -1. Is this some kind of typo, a misconception, or just bad engineering on your part? If you really mean 80 Mega-Kilo meters, then that's a silly way to say 80 Gm. – Olin Lathrop Jan 07 '14 at 16:16
  • Alternatively, \$8.0\times 10^{10} {\text m}\$. – Kaz Jan 07 '14 at 17:49
  • Now that you've updated the distance that time exceeds the speed of light, it would take close to 4.5 minutes for that distance. What's the on the other end, that's over halfway to the sun? – PeterJ Jan 08 '14 at 06:06
  • @PeterJ its the mothership ;) nah just kidding... Actually our amateur satellite which runs as a communications station for our MartianPi project –  Jan 08 '14 at 06:54
  • @DwightSpencer, it's probably worth adding that to the question and giving the comments a quick look over to add details asked such as usable data rate needed etc. – PeterJ Jan 08 '14 at 07:10

1 Answers1

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What is the best radio protocol for ... distance of upwards to 80M km?

For that distance, people use ISDCS protocols.

The long-haul standards are the internationally-agreed CCSDS “Packet Telemetry” and “Packet Telecommand”, which respectively permit the fully-standardized communication of spacecraft measurement and control information. These protocols have been specifically tailored to provide very high performance over weak, long-delay radio channels.

Ref

Obviously, to get "near-time (<= 3 mins)" comms - you have to wait for Mars to get a bit closer.

RedGrittyBrick
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