Methodology to find a new orbital position and channels

Methodology to find a new orbital position and channels

Thong Pham Viet

Space Services Department

[email protected]

WORKSHOP ON WRC-19 AGENDA ITEM 1.4

17th – 21st February 2020

Nairobi, Kenya

New orbital positions/channels

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Is a function of many factors like:- Elevation angle- Level of EPM values (Equivalent

Protection Margin) - Compatibility among your requests- Coordination with other

administrations- and others.


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Therefore, it is proposed to: (1) find orbital positions/channels

that meet your requirements on:- Elevation Angle- Level of EPM for 10 odd or

even consecutive channels (2) then assess other factors like

compatibility, coordination etc.


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Elevation Angle : Desirability of a minimum angle of elevation of 20°. For mountainous areas, an angle of elevation

greater than 300. For country with high rain attenuation, an angle of

elevation greater than 400. In some dry and non mountainous areas, an angle

of elevation may be less than 200.


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Level of EPM values

PR = 21 dB for Downlink and 27 dB for Feeder-link

Ii: Interference from assignments in the Plan/List located within +/-9 degrees from orbital position of wanted assignment. Interferencefrom assignments not yet entering in the List will not beconsidered. However, once those assignments enter in the List,EPM of wanted assignment will be re-calculated.


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Level of EPM values

It is not an absolute value.• In the downlink:

If you have EPM of 5 dB, your aggregate C/I level = 26 dB.


If you have EPM of -5 dB, your aggregate C/I level = 16 dB.


• In the feeder-link: If you have EPM of 5 dB, your aggregate C/I level = 32 dB.





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Level of EPM values

From aggregate C/I, you can calculate C/(N+I) to compare withyour required C/(N+I) so that you can check if EPM values are goodor not.


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Level of EPM values

From Recommendation ITU-R BO.1784-1: Required C/N values


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Level of EPM valuesOverall Required C/(N+I) (dB) 8

C/N Feeder-link (dB) 30

EPM Feeder-link (dB) -5

C/N Downlink with Rain (dB) 8 8.5 9 9.5 10 10.5 11 11.5 12 12.5 13 13.5 14

EPM Downlink (dB)

0 -0.399 0.055 0.503 0.946 1.383 1.814 2.237 2.653 3.06 3.458 3.846 4.224 4.591

-1 -0.45 -0.002 0.441 0.877 1.307 1.729 2.144 2.55 2.947 3.335 3.712 4.078 4.432

-2 -0.514 -0.072 0.363 0.791 1.212 1.625 2.029 2.424 2.81 3.184 3.548 3.9 4.24

-3 -0.592 -0.159 0.267 0.685 1.095 1.497 1.889 2.271 2.642 3.002 3.35 3.686 4.009

-4 -0.689 -0.266 0.149 0.555 0.953 1.341 1.719 2.085 2.44 2.783 3.114 3.431 3.735

-5 -0.808 -0.398 0.005 0.397 0.78 1.152 1.513 1.862 2.199 2.523 2.833 3.13 3.412

-6 -0.954 -0.557 -0.17 0.206 0.572 0.926 1.268 1.597 1.913 2.215 2.504 2.778 3.038

-7 -1.13 -0.75 -0.381 -0.023 0.323 0.657 0.977 1.284 1.578 1.857 2.122 2.372 2.608

-8 -1.343 -0.982 -0.632 -0.295 0.029 0.34 0.637 0.92 1.189 1.444 1.684 1.91 2.122

-9 -1.596 -1.256 -0.929 -0.615 -0.315 -0.028 0.244 0.502 0.745 0.974 1.189 1.39 1.578

-10 -1.896 -1.579 -1.276 -0.987 -0.712 -0.452 -0.206 0.026 0.244 0.447 0.637 0.814 0.977

-11 -2.246 -1.954 -1.677 -1.415 -1.166 -0.932 -0.712 -0.507 -0.315 -0.136 0.029 0.182 0.323

-12 -2.649 -2.385 -2.135 -1.899 -1.677 -1.47 -1.276 -1.096 -0.929 -0.775 -0.632 -0.501 -0.381

-13 -3.109 -2.872 -2.649 -2.44 -2.246 -2.064 -1.896 -1.74 -1.596 -1.464 -1.343 -1.232 -1.13

-14 -3.627 -3.417 -3.221 -3.038 -2.869 -2.712 -2.568 -2.435 -2.313 -2.201 -2.099 -2.005 -1.921

-15 -4.201 -4.018 -3.848 -3.69 -3.545 -3.411 -3.288 -3.176 -3.073 -2.979 -2.894 -2.817 -2.747

-16 -4.831 -4.673 -4.527 -4.392 -4.269 -4.156 -4.053 -3.959 -3.873 -3.795 -3.725 -3.661 -3.603

-17 -5.512 -5.377 -5.253 -5.14 -5.036 -4.942 -4.856 -4.778 -4.707 -4.643 -4.585 -4.533 -4.486

-18 -6.241 -6.127 -6.024 -5.929 -5.843 -5.764 -5.693 -5.629 -5.571 -5.518 -5.471 -5.429 -5.39

-19 -7.013 -6.918 -6.832 -6.753 -6.682 -6.618 -6.559 -6.507 -6.459 -6.417 -6.378 -6.344 -6.313

-20 -7.823 -7.745 -7.673 -7.609 -7.55 -7.498 -7.45 -7.407 -7.369 -7.334 -7.303 -7.275 -7.25

C/(N+I) – Required C/(N+I)

EPM

Do

wn

link

C/N Downlink with Rain


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(1) Find orbital positions/channels that meet your requirements on:

- Elevation Angle- Level of EPM for 10 odd or even consecutive

channels

Step 1: From minimum elevation angle, determine the range of GSOarc.

Step 2: Limit the GSO arc from 10E to the West.

Step 3: Scan the GSO arc by a step of 0.1 degrees. [See process]

Step 4: Identify positions that meet your requirements in bothdownlink and feeder-link.


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Example:- Administration : KEN- Minimum elevation angle: 20 degrees- GSO arc: -20.49 to 96.06- GSO arc from 10E: -20.49 to 10E- GSO arc size: ≈ 30 degrees.- Time required to scan all 30 degrees GSO arc in the downlink:

Creation of 300 notices using SpaceCap: 150 hours (300 * 30 minutes) Mspace running: 450 hours (300 * 1.5 hours). Total working days (8 hours): 75 days!



channels


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This step, we have done it for you using SPS_ALL_IFIC2912 and storedthem in the “WRC-19 A.I.1.4 Helping Tool” for all 31 ATU memberstates that are eligible to apply the Special Procedure.

- The Tool gives you all possible orbital positions further west than10E: Consecutive 10 odd/even channels with the same polarization Minimum EPM values greater than or equal to -10 dB Elevation angle greater than or equal to 10 degrees Indication whether a position is subject to Special Procedure.



channels


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If there is update in the SPS_ALL database from now to 21 May 2020in the GSO arc further west than 200E, you should review if there isany negative impact on the orbital position/channels you haveselected!



channels


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(2.1) Compatibility among your requests:to make sure that once your new Plan assignments enter in the List, you will not degrade among yourself.Some principles:- Same channels/polarizations/orbital

position >> separate in geography.- Same channels/polarizations/neighbouring

countries >> separate in orbital position.


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(2.2) Coordination with other administrations with:

- Assignments in the Plans- Assignments in the List- Pending Article 4 networks- Non-planned bands- Terrestrial services

Potentially affected by your new Plan assignments [maximum 10 channels].


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(2.2) Coordination with other administrations:

- If any Plan assignments are affected,you shall finish coordination ormodify characteristics so that Planassignments are no longer affected.


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(2.2) Coordination with other administrations with:

- Assignments in the List- Pending Article 4 networks- Non-planned bands

Potentially degrade levels of protection of your new Plan assignments.


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(2.2) Coordination with other administrations:

- The most challenge is the coordination with Regions 1 and 3 BSS Plan, List and Pending Article 4 networks because they are normally co-coverage and co-frequency.

- BR Soft application (MSPACE) is used to identified the potentially affected

administrations/networks in that case.

Process to check EPM at a particular orbital position

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At each orbital position, in Region 1, you can have up to 40 channels. Each channel can beassociated with different polarizations (Circular or Linear)Step 1: Create a filing with 8 frequency groups in the downlink at the new orbital position(see presentation “Changing parameters”):

Step 2: Assign the same Mspace group code (YY) to all 8 frequency groups.

Step 3: Export that filing into Master SPS_ALL_IFIC_XXXX database and assign group code

(YY) to your current Plan assignments and run Mspace.

Step 4: Identify if you can have 10 consecutive odd or even channels with the same

polarization that give you acceptable levels of EPM.

Step 5: if it is OK in the downlink, repeat Step 1 to Step 4 for the feeder-link.

Group Channels/Polarization

1 20 consecutive odd channels with circular left polarization (CL)

2 20 consecutive odd channels with circular right polarization (CR)

3 20 consecutive even channels with circular left polarization (CL)

4 20 consecutive even channels with circular right polarization (CR)

5 20 consecutive odd channels with vertical polarization (L/90)

6 20 consecutive odd channels with horizontal polarization (L/0)

7 20 consecutive even channels with vertical polarization (L/90)

8 20 consecutive even channels with horizontal polarization (L/0)

Documents

Methodology to find a new orbital position and channels