Sorry, I didn't finish the conlusion.
I conclude that, even if mobile will be raised to co-primary, it cannot benefit of the whoole 10% (because the 10% is fixed for all cp-primary and satellite shall have its share).
Then, but only for "new links", mobile could benefit of says 5% DP.
Roberto
On 13/12/19 12:48 Roberto Macchi wrote:
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Hi All,
maybe I can explain where the inconsistency lays from ITU-R side (and different CEPT side).
I don't want to enter the in the debate of were is the "legal truth"; however, in my opinion, here are the facts.
First of all, I assume that the issue is related to a possible CEPT Deciison to "raise mobile to co-primary status".
According ITU-R F.1094, the EPO objective should be maintained also in presence of interference (X from other links, Y from coprimary, Z from "other".
That means that, in principle, FS link planning should be done in presence of any interference. That means, still in principle, that the link, should be designed with some "margin" (e.g. the well known I/N 10 or 20 dB in the rain case).
However, while the 0.04 dB (1% for "other not co-primary" source) is practically irrelevant, the 0.5 dB (10%) for co-primary is not.
At this point ITU-R has never clarified if any link should be "overplanned" (independently if interference is present at the moment of deployment) or not. Obviously, for most links, when deployed up today, in CEPT the mobile service is not co-primary and Satellite interference might not impacting the link, it is higly probable that such 10% was not taken into account (or in any case given totally to Satellite interference). Here is the inconsistency !!!
The equations presented below are evidently made assuming that all links had the 1%+10% taken into account and this justify the "negative" result of the formula. However, from the point of view. However, from Mobile point of view, the 10% is no longer available for already deployed links. It might become certainly available whenever CEPT will raise mobile to co-primary (and for newly deployed links). For existing links I don't know, I believe it could be a "political only" decision.
I conclude that, even if
Kind regards
Roberto
On 13/12/19 11:41 Rabie Oularbi wrote:
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Dear all,
Following the chairman request, please find below an opening of discussions on the DP issue.
During the last SE45 meeting a multi-company contribution introduced a new way to compute the “Degradation in Perfomance (DP)”, deviating from the one agreed with SE19 during the joint SE19/45 webmeeting.
and .
In the equation above, one can see that the equation used in order to compute the outage probability in presence of fading only is different from the one considering fading and interference contributions. Indeed, the threshold used is equal to FFM in P1 and to Fa in P2 where Fa>FFM.
In the French view, this represents an inconsistency that needs to be corrected.
First, in terms of definition, the DP represents a quantitative estimation of how much the outage probability will degrade in presence of interference for a given link. If the link is designed with a given fade margin, whatever it is (FFM or Fa) it will continue its life with this fade margin. The FS link has no “intelligence” to distinguish between cases where the fade it is encountering is due to fading only or to fading plus interference, so that it can adjust it fade margin. Where in the case above, we are comparing two different links, one working with a fade margin equals to a first value FFM and another one working with a higher fade margin equals to Fa.
Second, technically speaking, following the equation proposed in the multi-company proposition, it appears that the degradation of performance is negative when the interference is muted. Which means that in the case that the interference is not active than the performance of the fixed link is enhanced compared with the case where the interference was not active (Two different values for the same scenario in fact).
Thus, this equation is introducing a non-sense estimation that does not technically stand and should be corrected. The thresholds are to be aligned, a fixed link has only one fade margin and is not able to choose between two values. P1 and P2 should both use the same threshold.
Best regards,
Rabie.
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