APPENDIX S8 OF RADIO REGULATIONS

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APPENDIX S8 OF RADIO REGULATIONS
COORDINATION ARC APPROACHCALCULATION OF C/I RATIO

• Yvon Henri
• RADIOCOMMUNICATION BUREAU

Mexico City, 24-28 September 2001
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CONTENTS

• AP S8 procedure for calculation of ?T/T
• Theoretical Background
• ?T/T calculations under different interference
  situations
• Coordination Arc Approach (CAA)
• Application of AP S8 CAA
• Necessity of C/I calculations
• Methodology for compatibility analysis
• Calculation Algorithms for C/I, C/N Margin, M
• Case studies

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THEORETICAL BACKGROUND
C/Ntot
S/N BER
D/C
Filter
Demod
Objective Keep I/N 4
THEORETICAL BACKGROUND
If N0 represents the noise density of the flat
noise spectrum such that N N0B Then N0
KT If Im represents maximum spectral density
of the incoming external interference I
Then I B and therefore I/N ?T is the increase in the system noise
temperature caused by Im
Then Im K ?T So,
Im/N0 ?T / T
We calculate Im/N0 because...

• knowledge of B, the receiver bandwidth, becomes
  unnecessary the integration of external
  interference density over the receiver bandwidth
  B to calculate total interference, is avoided
• if Im/N0 is below a threshold value, I/N will
  also be below that threshold value , most likely
  with some margin

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TRANSMISSION GAIN AND EQUIVALENT SATELLITE LINK
NOISE TEMPERATURE

• Prs Power received at satellite
• Pre Power received at E/S
• ? Transmission Gain
• ? Prs / Pre

Ts Sat. Receiver Noise Temp. Te E/S.
Receiver Noise Temp. T Equivalent Satellite
Link Noise Temp. T Te ? Ts
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THEORETICAL BACKGROUND
Wanted satellite network
Interfering satellite network
Im (p Gt Gr ) / L Since Im K ?T So,
?T Im / K ?T / T Im / KT ?T / T (p Gt Gr
)/KLT
Im is the interference power density at
the receive antenna output
Im/N0 ?T /T 7
WORST CASE INTERFERENCE SCENARIO IS CHOSEN WHILE
CALCULATING ?T/T

• Choice of
• wanted sat. network characteristics most
  susceptible to receiving interference
• interfering sat. network, likely to cause max.
  interference to wanted network.
• For this, the following are considered

• Highest values of wanted interfering sat.
  antenna gains
• Transmitting E/S of the interfering sat.
  network towards which, the wanted sat. receive
  antenna gain is the greatest
• Wanted receiving. E/S towards which, the
  interfering sat. transmitting antenna gain is
  the greatest
• Maximum power densities of interfering
  emissions
• Lowest value of T, Equivalent Satellite Link
  Noise Temperature (ESLNT) for wanted network
• Highest value of transmission gain ? for wanted
  network.

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FREQ. OVERLAP CO-DIRECTIONAL SEPARATE
TREATMENT OF UP DOWN LINKS
S(Interfering)
S (Wanted)
Freq.Overlap in downlink only
WANTED NETWORK HAS ONLY DOWNLINK NO UPLINK

(TELEMETRY
SIGNAL) INTERFERING POWER DENSITY ps CAUSES
ADDITIONAL NOISE TEMP. ?TE AT THE E/S RECEIVE
ANTENNA OUTPUT. ?TE / TE ps
G3 G4(?w) / LD KTE
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FREQ. OVERLAP CO-DIRECTIONAL SEPARATE TREATMENT
OF UP DOWN LINKS
Freq.Overlap in uplink only
S(Interfering)
S (Wanted)
WANTED NETWORK HAS ONLY UPLINK NO DOWNLINK.

(TELECOMMAND
SIGNAL) INTERFERING POWER DENSITY pe CAUSES
ADDITIONAL NOISE TEMP. ?TS AT THE WANTED SAT.
RECEIVE ANTENNA OUTPUT. ?TS / TS
pe G1(?i) G2 / LU KTS
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FREQ. OVERLAP CO-DIRECTIONAL WANTED SAT. HAS
SIMPLE FREQ. CHANGING TXP.
S (Wanted)
Freq.Overlap in uplink only
S(Interfering)
WANTED NETWORK HAS UPLINK AND DOWNLINK.
INTERFERING POWER DENSITY pe CAUSES ADDITIONAL
NOISE TEMP. ?TS AT THE WANTED SAT. RECEIVE
ANTENNA OUTPUT. ??TS / T ? pe G1(?i) G2 /
LU K T
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FREQ. OVERLAP CO-DIRECTIONAL WANTED SAT. HAS
SIMPLE FREQ. CHANGING TXP.
Freq.Overlap in downlink only
S (Wanted)
S(Interfering)
WANTED NETWORK HAS UPLINK AND DOWNLINK.
INTERFERING POWER DENSITY pS CAUSES
ADDITIONAL NOISE TEMP. ?TE AT THE WANTED E/S
RECEIVE ANTENNA OUTPUT. ?TE / T ps G3G4
(?W) / LD K T
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FREQ. OVERLAP CO-DIRECTIONAL WANTED SAT. HAS
SIMPLE FREQ. CHANGING TXP.
Freq.Overlap in both links
S(Interfering)
S (Wanted)
WANTED NETWORK HAS UPLINK AND DOWNLINK.
INTERFERING POWER DENSITIES pe pS CAUSE
ADDITIONAL NOISE TEMPS. ?TS AND ?TE (?TE
??TS )/ T 1/K Tps G3G4 (?W) / LD ? pe
G1(?i) G2 / LU
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BIDIRECTIONAL FREQUENCY USE UPLINK OF WANTED
NETWORK HAS FREQ. OVERLAP WITH DOWNLINK OF
INTERFERING NETWORK.
S (Wanted)
S(Interfering)
SIMPLE FREQ.CHANGING TXP.ON BOARD
THE WANTED SATELLITE. ??TS / T ? pS G3 (?S)
G2 (?S) / LS K T
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BIDIRECTIONAL FREQUENCY USE UPLINK OF WANTED
NETWORK HAS FREQ. OVERLAP WITH DOWNLINK OF
INTERFERING NETWORK.
S(Interfering)
S (Wanted)
SEPARATE TREATMENT OF UP DOWN LINKS. ?TS / TS
pS G3 (?S) G2 (?S) / LS K TS
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COORDINATION ARC APPROACH (CAA)

• COORDINATION IS TRIGGERED WITHOUT ?T/T
  CALCULATIONS WHEN INCOMING
• AND EXISTING GSO NETWORKS
• BOTH USE FIXED SATELLITE SERVICE (FSS) AND
  HAVE CO-DIRECTIONAL
• OVERLAP IN FREQUENCY BAND(S) SHOWN BELOW
• ARE LOCATED WITHIN PRE-DETERMINED GSO ARC AS
  INDICATED
• PRIMARY AIM OF REDUCING COORD. BURDEN ON
  ADMINISTRATIONS IN FREQ.
• BANDS WHERE MAJOR VOLUME OF NOTICES ARE
  RECEIVED BY THE
• RADIOCOMMUNICATION BUREAU

APPLICABLE COORD. ARC /- 10 of nominal
orbital position of a proposed network in FSS
. /- 9 of nominal orbital position of a
proposed network in FSS . /- 8 of nominal
orbital position of a proposed network in FSS .
FREQ.BANDS (MHz / GHz) 3400 - 4200 5725
- 5850(RG1) 5850 - 6725 10.95 - 11.2
11.45 - 11.7 11.7 - 12.2 (RG2)
12.2 - 12.5(RG3) 12.5 - 12.75 (RG13)
12.7- 12.75(RG2) 13.75 - 14.5 17.7 - 20.2
27.5 - 30.0
This includes use of space operation service
ED, EK, ER.
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COORDINATION ARC APPROACH (CAA) cont.

• 1. HAVE EC(FSS) /OR EK, ED, ER (SP
  OPN.SERVICE)
• ARE CODIRECTIONAL
• ARE WITHIN SPECIFIED FREQUENCY BANDS
• 4. HAVE FREQUENCY OVERLAP
• 5. BELONG TO SATELLITE NETWORKS THAT ARE LOCATED
  WITHIN COORD. ARC.

CASE I CONDITIONS 1 TO 5 ARE MET CAA APPLIES
AND COORDINATION IS TRIGGERED WITHOUT DT/T CALC.
CASE II CONDITIONS 1 TO 4 ARE MET CAA DOES
NOT APPLY
CASE III ANY SITUATION OTHER THAN CASE I OR II
ABOVE ? T/T 6 TRIGGERS COORDINATION
EXEMPTION FROM COORDINATION PROCESS CAN BE
REQUESTED IF ?T/T , CALCULATED BY TREATING UP
DOWN LINKS SERARATELY, IS LESS THAN 6.
INCLUSION IN COORDINATION PROCESS CAN BE
REQUESTED IF ?T/T CALCULATED BY TREATING UP
DOWN LINKS SERARATELY, IS GREATER THAN 6.
LIST OF AFFECTED ADMINISTRATIONS SAT. NETWORKS
PUBLISHED BY BR.
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COORDINATION ARC APPROACH (CAA)

• WHEN EXISTING GSO NETWORKS IN FSS FREQUENCY
  BANDS, WHERE COORDINATION ARC APPROACH IS
  APPLICABLE, ARE LOCATED OUTSIDE THE CORDINATION
  ARC, COORDINATION IS NOT TRIGGERED BUT CAN BE
  REQUESTED IF ?T/T, CALCULATED BY SEPARATE
  TREATMENT OF UP DOWNLINKS IS MORE THAN 6 .

• WHEN EXISTING GSO NETWORKS IN FSS FREQUENCY
  BANDS, WHERE COORDINATION ARC APPROACH IS
  APPLICABLE, ARE LOCATED INSIDE THE COORDINATION
  ARC AND IF ?T/T , CALCULATED BY SEPARATE
  TREATMENT OF UP DOWNLINKS IS LESS THAN 6 ,
  REQUEST CAN BE MADE FOR EXCLUSION OF THE NETWORK
  FROM THE PROCESS OF COORDINATION.

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SUMMARY OF CONDITIONS FOR COORDINATION BETWEEN
INCOMING AND EXISTING GSO NETWORKS

• COORDINATION TRIGGERED BY COORD. ARC APPROACH.

• COORDINATION TRIGGERED BY OVERALL ?T/T 6
  FOR GSO NETWORKS FOR WHICH COORD. ARC. APPROACH
  DOES NOT APPLY.

• COORDINATION REQUESTED BY ADMINISTRATIONS FOR
  GSO NETWORKS USING CAA FREQUENCY BANDS BUT
  LOCATED OUTSIDE THE COORDINATION ARC WHEN ?T/T
  6 BY SEPARATE TREATMENT OF UP DOWN LINKS

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C/I CALCULATIONS
NECESSITY FOR C/I CALCULATIONS

• ONLY THE NEED FOR COORD. IS ESTABLISHED BY CAA
  ?T/T 6
• ?T/T 6 DOES NOT NECESSARILY INDICATE
  UNACCEPTABLE INTERFERENCE BECAUSE CALCULATION OF
  ?T/T DOES NOT TAKE INTO ACCOUNT -

• SPECTRUM SHAPE OF THE INTERFERENCE- ONLY THE
  UPPER
• BOUND VALUE OF I/N (i.e. Im/N0) IS
  CONSIDERED
• EXTENT OF FREQUENCY OVERLAP BETWEEN WANTED
  SIGNAL INTERFERENCE
• LEVEL OF WANTED SIGNAL
• FILTERING EFFECTS OF THE RECEIVER.

PROBABILITY OF HARMFUL INTERFERENCE IS THEREFORE
ASSESSED BY CALCULATION OF C/I.
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C/I CALCULATION METHODOLOGY
PART B SEC. B3 OF RULES OF PROCEDURE

• AS A RESULT OF CONTINUING DISAGREEMENT
  (NOS.S9.63 TO S9.65), NOTIFYING ADMIN. REQUESTS
  RADIOCOMM. BUREAU AND AN EXAMINATION OF
  HARMFUL INTERFERENCE IS CARRIED OUT UNDER No.
  S11.32A BY THE BR
• THIS EXAMINATION IS BASED ON RECOMMENDATION
  ITU-R S741-2. TABLE 2 OF THIS RECOMMENDATION
  GIVES SINGLE ENTRY INTERFERENCE (SEI)
  PROTECTION CRITERIA FOR FSS CARRIERS
• THIS CRITERIA, OR THE MUTUALLY AGREED CRITERIA
  FOR ACCEPTABLE INTERFERENCE AND A SET OF TEST
  POINTS MAXIMUM 20, PROVIDED BY THE
  ADMINISTRATION, ARE USED BY THE BR TO DECIDE
  THE FINDINGS

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METHODOLOGY FOR COMPATIBILITY ANALYSIS 1

• STEP 1 CALCULATION ALGORITHM - C/I
• Calculate
• (C/I )b ?Basic value of C/I. Use geometrical
  considerations of REC.ITU-R S740
• (C/I )a (C/I )b Ia ? Adjusted value of
  C/I
• Ia
  ? Interference/bandwidth adjustment factor
• (C/I ) separately for up down links using
  values of Ia for each link, as follows
• (C/I )u ? Worst case uplink value of
  adjusted C/I at any uplink test-point (dB)
• (C/I )d ? downlink value of adjusted C/I
  for a particular downlink testpoint(dB)
• (C/I )T ? Overall value of adjusted C/I
  for a particular downlink test-point(dB)

Case 1 (C/I )T (C/I )u when there is no
downlink for wanted or interfering system
or both, or no
frequency overlap in the downlinks of wanted
and interfering
systems.
Case 2 (C/I )T (C/I )d when there is no uplink
for wanted or interfering system or
both, or no frequency overlap
in the uplinks of wanted and
interfering systems
When both up down links exist for wanted
interfering systems and freq. overlap exists in
both directions
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METHODOLOGY FOR COMPATIBILITY ANALYSIS 1 (cont.)
INTERFERENCE ADJUSTMENT OR BANDWIDTH ADV. FACTOR
A (dB) C/I
10log(c/i) - A dB Here, c i are powers of
desired int. carriers, respectively.
A Int. carrier power in wanted signal BW /
Total int. carrier power A1 Used for
interference from noise like digital carriers
that are assumed to have uniform power spectral
density across its occupied bandwidth. A2 Used
for interference from noise like analog carriers
that are assumed to have uniform power spectral
density over the bandwidth of the wanted carrier
the same is equal to the maximum value.
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METHODOLOGY FOR COMPATIBILITY ANALYSIS 1 (cont.)
A1 ? Interference Adjustment Factor 1 A2 ?
Interference Adjustment Factor 2 B ?
Interference Reduction factor as detailed in Rec.
ITU-R SF.766 ()? This protection ratio
relaxation is applied to the K factor of 14 dB.
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METHODOLOGY FOR COMPATIBILITY ANALYSIS 2

• STEP 2 CALCULATION ALGORITHM - C/N MINIMUM
  DESIRED C/I
• Calculate Receive system noise N (for up and
  down links) using the expression
• N - 228.6 10 log10(TR) 6
  log10(BW) (dBW)
• 
  TR Receiving system noise temperature
  (?K)
• BW
  Receiving system Bandwidth (MHz)
• Calculate C/N at each test point
  (C/N)dBW CdBW - NdBW
• Calculate(C/N )T i.e. overall value of C/N (dB)
  for a particular downlink test pt.

Case 1 (C/N )T (C/N )u i.e. worst case C/N
(dB) at any uplink pt. when no freq. overlap
exists in downlinks of wanted int. signals
Case 2 (C/N )T (C/N )d i.e. downlink C/N
(dB) for a particular downlink test pt. when
no freq. overlap exists in downlinks of wanted
int. signals
When both, up down links exist for wanted
Int. systems and freq. overlap exists in both
directions
MINIMUM DESIRED (C/I ) min.desired (C/N )T
K Factor K depends on mod.char. Of wanted signals
takes on Values 14.0 or 12.2 dB as per Table 2
of Rec. ITU-R S741-2
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METHODOLOGY FOR COMPATIBILITY ANALYSIS 3
STEP 2 CALCULATION ALGORITHM MARGIN M
Margin M (C/I )a - (C/I)m
(dB)
(C/I)a Adjusted value of C/I , taking into
account interference adjustment
factor (dB) (C/I)m Minimum desired C/I ,
computed at each test point, (therefore,
Margin M will also vary for each
test-point) (dB) (C/I)m (C/N)T K K?
Factor used for computing (C/I)m (dB)
Therefore
M (C/I )a - (C/N)T - K
(dB)
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CASE STUDY 1 CALCULATION OF ?T/T , C/I, C/N
MARGIN, M
INTERFERING MARECS IND-1 (64.5/-0.1E)
WANTED (AR11/C/1880) INTELSAT7 66E (66/-0.1E)
G4m 49.1 dBW
?T ?TE ??TS
T TE ?TS
Geocentric angle (?g ) (66-0.1) (64.50.1)
1.3? d 42644(1- 0.2954Cos?)1/2 ?
Cos(latitude of Earth Station).Cos(diff. In long.
between E/S Satellite) L 20 log10 freq.
log10 d 32.45 (dB) ?w cos 1d22
d42 (84332sin(?g/2))2/2 d1 d2 ?i cos
1d42 d52 (84332sin(?g/2))2/2 d4 d5
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CASE STUDY 1 (cont.) CALCULATION OF ?T/T , C/I,
C/N MARGIN, M
Margin, M In accordance with the ITU Rec.
S.741-2 the Single Entry Protection Criteria
(C/I)minimum required (C/N)total 12.2 dB
15.08 12.2 27.28 dB Margin, M (C/I)Total
- (C/I)min. reqd 34.9327.28 7.65 dB M
7.65 dB
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CASE STUDY 2 CALCULATION OF ?T/T , C/I, C/N
MARGIN, M
INTERFERING MARECS IND-1 (64.5/-0.1E)
WANTED (AR11/C/1880) INTELSAT7 66E (66/-0.1E)
?T ?TE ??TS
T TE ?TS
Geocentric angle (?g ) (66-0.1) (64.50.1)
1.3? d 42644(1- 0.2954Cos?)1/2 ?
Cos(latitude of Earth Station).Cos(diff. In long.
between E/S Satellite) L 20 log10 freq.
log10 d 32.45 (dB) ?w cos 1d22
d42 (84332sin(?g/2))2/2 d1 d2 ?i cos
1d42 d52 (84332sin(?g/2))2/2 d4 d5
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CASE STUDY 2 (cont.) CALCULATION OF ?T/T , C/I,
C/N MARGIN, M
Margin, M In accordance with the ITU Rec.
S.741-2 the Single Entry Protection Criteria
(C/I)minimum required (C/N)total 12.2 dB
15.284 12.2 27.484 dB Margin, M
(C/I)Total- (C/I)min. reqd 24.9727.484-2.514dB
M - 2.514 dB
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CONCLUSIONS

• ?T /T Vs C/I CASE STUDIES ILLUSTRATE THAT
• SAME COMBINATION OF WANTED INTERFERING SIGNALS
  ON ONE HAND INDICATES NEED FOR COORDINATION (?T
  /T 31620) AND SHOWS COMPATIBILITY ON THE
  OTHER Margin, M 7.65 C/I 34.93dB
  (C/I)Min.reqd. 27.28dB.
• ANOTHER COMBINATION OF SIGNALS IN THE SECOND
  CASE STUDY, GIVES ?T/T64 (NEED FOR COORD.) AND
  A NEGATIVE MARGIN, (M - 2.514 dB) SHOWING
  INCOMPATIBILITY.
• IT CAN THEREFORE BE INFERRED THAT
• WHEN ?T /T EXCEEDS 6, THE C/I CALCULATION NEED
  NOT
• NECESSARILY INDICATE UNACCEPTABLE
  INTERFERENCE
• COMBINATION OF SIGNALS WHICH PRODUCES WORST CASE
  ?T /T
• NEED NOT PRODUCE WORST CASE C/I. THIS IS
  BECAUSE THE
• NATURE OF ?T /T REPRESENTS UPPER BOUND I/N
  WHEREAS, THE
• MARGIN IN ONE COMBINATION CAN BE LARGE, IT CAN
  BE SMALL
• FOR THE OTHER COMBINATION.

• COORDINATION ARC APPROACH (CAA) ALLOWS
• AFFECTED ADMINIS. TO BE IDENTIFIED IN A SMALL BUT
  MOST LIKELY
• PORTION OF THE GSO WITHOUT ANY ?T /T
  CALCULATION.
• EXISTING NETWORKS USING CAA FREQ. BANDS AND
  LOCATED OUTSIDE THE COORD. ARC MAY ALSO BE
  CONSIDERED IN THE COORD. PROCESS WHEN ?T /T
  CALCULATION USING A SIMPLER TECHNIQUE
  (SERARATION OF UP DN LINKS) SHOWS AN EXCESS
  BEYOND 6.