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Station Transmission Constraints on Re-Broadcast

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PaulRuskin:
I tend to agree that 5km is too little - I don't think it allows for much planning time, even assuming the PAW output is frequently in the pilot's scan.  Other things being equal, 10km is better.
Maybe there's an algorithm where if it gets busy, the traffic further away is dropped first.

Paul

Admin:

--- Quote from: PaulRuskin on January 26, 2018, 11:00:51 am ---...Maybe there's an algorithm where if it gets busy, the traffic further away is dropped first.

--- End quote ---

In fact, this is exactly the way it works right now.
The OGN-R creates a prioritized list of what it wants to send - based upon the individual TPR's, then it sends as much data as it should legally fill, in reality, it is constrained to be much less than the legal requirement.

I had a TODO, which was to consider rotating the list so for example, lets say we had 20 critical aircraft we wished to transmit, but we could only fit 10 into the available bandwidth, then should we rotate the list on the second iteration so the repeat interval per aircraft reduces, but all the important data has the opportunity to be sent, but at a slower rate.
Something to consider

Thx
Lee

exfirepro:

--- Quote from: Admin on January 26, 2018, 12:00:12 pm ---
.........In fact, this is exactly the way it works right now. The OGN-R creates a prioritized list of what it wants to send - based upon the individual TPR's, then it sends as much data as it should legally fill, in reality, it is constrained to be much less than the legal requirement.

I had a TODO, which was to consider rotating the list so for example, lets say we had 20 critical aircraft we wished to transmit, but we could only fit 10 into the available bandwidth, then should we rotate the list on the second iteration so the repeat interval per aircraft reduces, but all the important data has the opportunity to be sent, but at a slower rate.
Something to consider

Thx
Lee

--- End quote ---

Lee, This sounds like the way to go. Certainly better than ‘over restricting’ (IMO) the TPR to 5Km. I’m not disagreeing in any way with Mike about the difficulty in seeing aircraft (especially gliders or fast moving Tucanos) at longer range, but that is exactly why we need PAW / OGN-R.

Regards

Peter

Winged_Jaguar:
Thanks Lee. Interesting thread.

I would rather see the full (10%) duty cycle utilised but where it is likely to be exceeded then prioritise for those closest radius to the ground station. My thinking is that I would rather be getting a longer general view of what is about ahead of me to improve situational awareness as well as the alerts for immediate attention. If OGN-R is normally throttled to only give foreshortened range data it means one has to keep looking down to get an update rather than look out. Worse it may create more gaps between stations where we currently already have poor coverage. There is an inherent assumption in this that one is listening to the closest base station but for some without the benefit of a decent external aerial systems in the plane, the poor placement of the internal aerials means that reception is often patchy; somewhat directional and not necessarily close-by. At the moment at PWRADLEY I'm seeing relatively low utilisation (frequent Benson traffic) although when a swarm of gliders comes over in the summer it all gets more active.  In the plane I have benefited from OGN-R transmissions that have highlighted gliders that are in my immediate vicinity and been glad of the warning. Am I right in thinking that two base stations close to each other will tend to transmit over each other or is there a collision detect process built in to the transceiver to limit this?

Keep up the good work.
Thx Chris

Admin:

--- Quote from: Winged_Jaguar on January 26, 2018, 04:38:54 pm ---Thanks Lee. Interesting thread.
I would rather see the full (10%) duty cycle utilised but where it is likely to be exceeded then prioritise for those closest radius to the ground station

--- End quote ---

Hmm, interesting thought
the difficulty here is deciding the tradeoff, which is more important
TPR=5 SPR=10
or
TPR=10 SPR=5
I am sure you get my point, what is the intersect


--- Quote ---My thinking is that I would rather be getting a longer general view of what is about ahead of me to improve situational awareness as well as the alerts for immediate attention. If OGN-R is normally throttled to only give foreshortened range data it means one has to keep looking down to get an update rather than look out.
--- End quote ---
agreed, if you are not using any kind of audio connection


--- Quote ---... Am I right in thinking that two base stations close to each other will tend to transmit over each other or is there a collision detect process built in to the transceiver to limit this?
--- End quote ---
Yes they will overlap, and in a non-deterministic manner - there is no synchronisation, but measures are taken to randomise an element of the interval periods so that transmission overlay (when encountered) is not repeated

thx
Lee

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