TECHNICAL REPORT £390

SPECTRUM ORBIT UTILIZATION PROGRAM TECHNICAL MANUAL

SOUPS VERSION 3,8

13 DECEMBER 198|

SPECTEUH OEEIT UTILIZATION

FEOGE&M TECHNICAL MANUA L SCOPS VEBSIOH 3.8

(Operations Research, Inc.) n p

HC A05/WF A01

 CSCL 17B

G3/32

N86-26489

Unclas

43458

, DAVIDSON., H,

F, S, ZllSMAN

FTEY, >AWITZ &

PREPARED UNDER CONTRACT No, NAS3-22885

FOR NASA LEWIS RESEARCH CENTER
OKI

Silver Spring, Maryland 20910

SPECTRUM ORBIT UTILIZATION PROGRAM

TECHNICAL MANUAL

SOUPS VERSION 3,8

13 DECEMBER 1984

BY

J, DAVIDSON, H, R, OTTEY, P, SAWITZ &

F, S, ZUSMAN

PREPARED UNDER CONTRACT No, NAS3-22885

FOR NASA LEWIS RESEARCH CENTER
II.

III.

TABLE OF CONTENTS

PAGE

INTRODUCTION

1.1 PURPOSE AND SCOPE

1 2 R2BCSAT-83 COMPUTATIONAL SYSTEM OVERVIEW ....

1.3 SOUPS SYSTEM SUMMARY

1 4 HISTORY . .

1.5 FORMAT OF THIS REPORT

SOUPS TECHNICAL OVERVIEW

2.1 INPUT FILES

2 2 PROGRAMS

2.2.1 Program 1

2.2.2 Program 2

2.2.3 Program 3

2.3 HARDCOPY AND BINARY OUTPUTS

2.4 TECHNICAL CAPABILITIES ...

2 5 TECHNICAL PROCESSING SEQUENCE

2.6 TECHNICAL OPTIONS

GEOMETRY

3 1 COORDINATES AND POSITIONS > . . .

3 2 RANGE

3.3 OFF -AXIS ANGLES

3 4 ELEVATION ANGLE

3.5 ELLIPSE ORIENTATION

. . . 1-1

. . . 1-1

. . . 1-2

. . . 1-3

. . . 1-4

. . . 1-5

. . . 2-1

. . . 2-1

. . . 2-4

. . . 2-5

. . . 2-7

. . . 2-10

. . . 2-14

. . . 2-17

. . . 2-17

. . . 2-21

. . . 3-1

. . . 3-1

. . . 3-2

. . . 3-2

. . . 3-3

. . . 3-3
TABLE OF CONTENTS

(Continued)

PAGE

IV. ANTENNA GAINS 4-1

4.1 BEAMWIDTH 4-1

4.2 ON-AXIS GAIN 4-2

4.3 OFF-AXIS GAIN 4-2

V. RAIN ATTENUATION AND DEPOLARIZATION 5-1

5.1 GENERAL DESCRIPTION 5-1

5.2 AVERAGE YEAR AND WORST MONTH STATISTICS 5-1

5.3 ESTIMATED HEIGHT OF RAIN ABOVE MEAN SEA LEVEL (HR)

AND SLANT PATH LENGTH THROUGH THE RAIN (Lg) 5-2

5.4 SLANT PATH DISTANCE THROUGH RAIN 5-2

5.5 SLANT PATH REDUCTION FACTOR 5-3

5.6 SPECIFIC ATTENUATION CORRESPONDING TO THE PARTICULAR

CLIMATIC ZONE 5-3

5.7 POLARIZATION TILT ANGLE 5-4

5.8 RAIN ATTENUATION 5-5

5.9 FREQUENCY SCALING 5-5

5.10 CROSS POLARIZATION DISCRIMINATION 5-6

VI. EQUIVALENT GAIN, TRANSMITTER POWER AND RECEIVED POWER ... 6-1

6.1 EQUIVALENT GAIN 6-1

6.2 TRANSMITTER POWER 6-2

6.3 RECEIVED POWER 6-4

VII. CHANNELIZATION AND PROTECTION RATIOS 7-1

7.1 NOMINAL WAVELENGTH . . 7-1

7.2 INTERFERENCE CATEGORIES 7-1

7.3 CHANNELIZATION SCHEME (RARC PARAMETERS) 7-2

7.4 PROTECTION RATIOS 7-3

7.5 CHANNELIZATION SCHEME AND CHANNEL FAMILY 7-4

ii
TABLE OF CONTENTS

(Continued)

PAGE

VIII. AGGREGATE AND TOTAL INTERFERENCE ANDD MARGINS 8-1

8.1 AGGREGATE AND TOTAL INTERFERENCE 8-1

8.2 AGGREGATE AND TOTAL MARGINS 8-2

8.3 GROUPING 8-3

8.4 NON-INTERFERENCE MATRIX 8-4

REFERENCE R-l

APPENDIX A: EQUIVALENT GAIN FOR EACH PARTIAL LINK A-l

iii
I. INTRODUCTION

1.1 PURPOSE AND SCOPE

The purpose of the SOUPS Version 3.8 Technical Manual is to describe

the underlying engineering and mathematical models as well as the

computational methods used by the SOUPS analysis programs, which are a part of

the R2BCSAT-83 Broadcast Satellite Computational System. This system was

developed for use at the Regional Administrative Radio Conference (RARC-83)

held in Geneva in June of 1983. Version 3.8 is equivalent to the program used

to establish the Region 2 plan at the conference. However, it should be noted

that the International Frequency Registration Board was empowered by RARC-83

through its Resolution COM 5/1 to further modify the software for the purpose

of preparing a final prediction of mutual interference levels for applications

under the plan agreement. This may result in predictions that differ from

those made at the RARC-83.

Included in this manual are the alogrithms used to calculate the

technical parameters and references to the relevant technical literature. Not

included are a detailed discussion of how to use and interpret the output of

the SOUPS analysis programs, detailed descriptions of the inputs and hardcopy

(printed) outputs of the SOUPS program, nor summary descriptions of the

program themselves. These are fully documented in the SOUPS Version 3.8 User

Manual. Nor is there a description of the program code and structure or the

program's data structures (including the COMMON blocks and binary file

interfaces). These are documented in the SOUPS Version 3.8 Programmer's

Manual.

1-1
1.2 R2BCSAT-83 COMPUTATIONAL SYSTEM OVERVIEW

The SOUP5 programs provide the plan analysis capability of the

R2BCSAT-83 Computational System. The R2BCSAT-83 Computational System was

designed to satisfy the computational requirements of the 83 RARC. The system

provides the following capabilities:

• Requirements File Maintenance

• Data Base Maintenance

• Elliptical Satellite Beam Fitting to Service Areas

• Plan Synthesis from Specified Requirements

• Plan Analysis (System Performance and Inter-System Interference)

• Report Generation/Query

This section provides a brief description of each of these functions.

Prior to RARC-83, the ITU collected the broadcast satellite service

requirements information from each ITU Region 2 administration. This Includes

such information as the locations and rain zones of performance/interference

test points for the service areas 1n the plans to be developed. These data

have been keyed and are now maintained in a data base. They are available for

report generation, querying, and as input to the computational routines.

The technical parameters for the conference as well as plans under

consideration are maintained in a data base which is accessible for report

generation, querying, and input to computational routines. The data base also

includes the results of the Beam Fitting and Synthesis Modules.

The Beam Fitting Module of the system computes the parameters of the

satellite antenna beam from a specified satellite location which best fits a

set of points defining a service area. The outputs of this program are in the

data base.

The Plan Synthesis Module assists a planner in the development of

downlink plans. These prospective plans are stored in the data base and are

used as input to the Plan Analysis Module by means of an Interface program.

1-2
The Plan Analysis Module consists of the SOUPS system described in

this manual. SOUP5 computes the aggregate interference (uplink, downlink, and

total including co-channel, adjacent channel and second adjacent channel) for

all the service areas in a plan. A plan can come from the Plan Synthesis

Module or be generated manually by a planner. The latter was necessary at

RARC-83 because the synthesis module could not process the large number of

requirements with sufficient speed. The printed outputs of the SOUPS module

are summary and detailed reports as well as diagnostic information. The

module also generates a binary output file for use by the Report

Generation/Query Module. SOUPS is written in FORTRAN and currently runs on

the PRIME 400, IBM 370 compatible computers, the VAX 11/780 and the SEIMENS

computer at the ITU.

The Report Generation/Query Module permits a planner to query the

data base to determine the values of selected parameters or to generate

reports on a preformatted or ad hoc basis using data from any part of the data

base - Requirements, Technical Parameters, Results, or Analysis Results.

1.3 SOUPS SYSTEM SUMMARY

The principal purpose of SOUPS is to compute the mutual interference

between a large number of broadcast satellite links for ground stations at

specified locations operating through satellites in specified orbital

positions. Since mutual interference is the main limiting factor in the use

of the geostationary arc by many systems operating in the same frequency band,

SOUPS is a most valuable tool in the planning or analysis of spectrum-orbit

utilization.

An additional purpose of SOUPS is to compute certain associated

performance parameters, such as power flux density and received power, which,

while not directly related to mutual interference, nevertheless are useful in

the analysis of satellite communication systems.

SOUPS is designed to be used for systems in the BroadcastingSatellite Service (BSS) with 17 GHz uplinks and 12 GHz downlinks. The

propagation model, channelization characterization, antenna types, and/or

1-3
interference interaction evaluation methodologies could require modification

for other applications. The program handles as many as 300 service areas,

2400 feederlink transmitters (FLT) and 2400 earth station receivers (ESR) in

one run. Each link must be described in terms of its geometrical and

communication parameters. Some of the more significant input parameters

considered are carrier frequency, polarization, channelization schemes,

antenna off-axis gain patterns, antenna diameters or beamwidths, and ground

terminal and satellite locations.

The standard output is a set of interference reports for up, down,

and total aggregate interference. A report giving intermediate results is

optionally available. Extensive detailed printout for the subprograms in the

system are available as debug options.

1.4 HISTORY

The Spectrum Orbit Utilization System (SOUP) was originally developed

by General Electric, Space Systems Organization, Valley Forge Space Center, in

1969/70 as part of a study of the technical and economic aspects of

spectrum-orbit utilization under Contract No. OEP-SE-69-102. This work was

first monitored by the Office of Telecommunications Policy, Executive Office

of the President, with funding also supplied by NASA and the FCC. Later, the

responsibility for this effort was transferred to NASA. The system was

written for use on the IBM 360/44 computer. In June 1971, ORI, primarily

under NASA sponsorship with some assistance from the NTIA, started to adapt

the system for use on the IBM 360/95 computer and to make several

modifications to enhance its utility as a tool in a study of domestic

communication satellite systems. A document describing the modified SOUP was

2 3 published in 1974. A 1980 document describes further enhancements. An

updated document describing the enhanced version (SOUP3), which can be used to

analyze the interference between systems transmitting television, telephony

4

and data, was published in 1981. This manual describes the technical

details of the version of the system which is called SOUPS* Version 3.8 which

has been designed to handle broadcast satellite systems only.

1-4
1.5 FORMAT OF THIS REPORT

Section II, (Overview) describes the organization, capabilities,

processing sequences, and processing and data options of the SOUPS system.

Section III (Geometry) gives the details of the geometric calculations.

Section IV (Antenna Gains) describes the various antenna gain algorithms

used. Section V (Rain Attenuation) discusses the rain attenuation and

depolarization calculations. Section VI (Equivalent Gain, Transmitter Power

and Received Power) details the calculations of transmitter power and

resulting power flux density. Section VII (Channelization and Protection

Ratio) describes the channelization options, interference categories, and

protection ratio calculations. Section VIII (Margins, Aggregate Interference

and Grouping) describes the generation of aggregate interference and margins.

Appendix A describes the equivalent gain calculation in detail.

*SOUP4, an enhanced version of SOUPS, was superseded by SOUPS Version 1 before

it was distributed to the user community.

1-5
II. SOUPS TECHNICAL OVERVIEW

The SOUPS analysis system currently consists of three programs and

their associated Input and output files. The flow chart In Figure 1 shows the

Input and output files used by SOUPS. Each file 1s labeled with the Data Set

Name (DSN) used In the JCL which accompanies the program (see Appendix C of

the User's Manual). For files without a DSN (i.e., Sysout = A for printout,

or DD * for input in JCL stream) a descriptive name is enclosed in

parentheses. Each arrow is labeled with the FORTRAN unit number of the file

as implemented on IBM computers and the name of the internal program variable

containing the FORTRAN unit number. The unit numbers themselves are read from

files Pl.DATA, P2.DATA and P3.DATA so that individual installations may change

them to suit their own conventions. The following paragraphs summarize the

components — both programs and data ~ of the system.

2.1 INPUT FILES

SOUPS reads six input files in program PI and one 1n Program P3 to

assemble the data necessary to perform subsequent calculations. These files

(except those written by the IFRB) contain sequentially organized, card image

data. The Program 1 input files are the following:

2-1
NRMF

Requirements

33 IUREQ

*

P1.

DATA

CONTROL

DATA

' ' 32 IUELL1

10 IUICTL

SCENARIO:

DATA

oa IUSCEN

PARAMS.

DATA 7

9 IUPAHM

INPUT

31 IUELL2 / DEP

(DOWN

ELLIPSES)

11 IURPT

21 INBIN

(P2. DATA)

DD'

IOUTBN

IOUTBN

FIGURE 1

SOUPS - SYSTEM FLOWCHART

14 IUW(2)

r

L.

r^

I

*

P

1

22 IN8IN

p

2

u inn,B1wn

13IOIAG ^

12 IERUNT

13 DIAG

8 IAGG1

17IRPT1

16 IRPT2

18IRPT3 (P3. IRPT3)

SYSOUT -A

2-2
System and Run Control Data:

DATA.PI - Contains error message formats, file unit

assignments, and other internal program PI data.

DATA.CONTROL - Contains

Name of scenario-plan for this run

Process up and/or down option

Reports to be written

Debug printout flags for programs PI through P3.

R2BCSAT-83 Data Base Data:

DATA.SCENARIO contains a set of scenario-plans. Program PI

selects and processes one of them. Up to 300* service

areas, 2400* feeder!inks and 2400* earth station receivers

can be accommodated in any one plan.

DATA.PARAMETERS contains

RARC Parameters

Channelizations

Protection Ratio Sets

Point Sets (alternatives for the Requirements files)

Ellipses (alternatives for the official ellipse files)

Antenna Characteristics Sets

Gain Tables

ELLIPSE FILES (one for up and one for down) contain

official IFRB ellipses

REQUIREMENTS FILE contains data from requirements forms

submitted to the IFRB.

* Numbers can be changed during installation.

2-3
Input file P3.IMATRX is read in Program P3. This file allows the

user to inhibit the interference calculations between specified service areas

in either direction. It may be created by the user, or by the synthesis

program.

Each of these files is fully described in Chapter 3 of the SOUPS

Version 3.8 User's Manual.

2.2 PROGRAMS

The three programs comprising SOUPS are:

Program 1 - Selects the data from the data base which are needed for

the run and assembles them into a form usable by programs

P2 and P3, echo printing the selected data while checking

and editing them for completeness and consistency.

Program 2 - Perform intra-system calculations: unit conversions

(e.g., dB to numerics); transformation to Cartesian

coordinates; calculations of protection ratios by

interference category; determination of interference

categories by channel family; computations of on-axis

gains, transmitter power, etc.

Program 3 - Performs "cross" calculations (i.e., for up, each

satellite vs. all feeder!ink test points; for down,

each earth station receiver test point vs. all

satellites). Calculations performed include:

gain, received signal power, attenuation, C/I and

margines. Produces summary aggregate interference

reports for up, down, and total.

Each of these programs is summarized below.

2-4
2.2.1 Program 1

As explained above, Program 1 reads the six input files, selects the

needed data, checks and edits them, and assembles them into a form usable by

Program 2 and 3.

The main program in Program 1 invokes in sequence the following

top-level subroutines:

INIT

PRCTL

PRSCEN

PRRARC

PRSERV

PRCHAN

PRPROT

PRPNTS

PRBEAM

PRANG

PRGAIN

PRSIZE

Read DATA.PI and initialize the run

Process control inputs in DATA.CONTROL

Process scenario level data and scenario description

in DATA.SCENARIO

Process RARC parameters in DATA.PARAMS

Process scenario service areas and point overrides in

DATA.SCENARIO

Process channelization data in DATA.PARAMS

Process protection ratio data in DATA.PARAMS

Process points sets and points in DATA.PARAMS and

Requi rements

Process ellipse data in DATA.PARAMS and the Ellipse

File

Process antenna characteristics in DATA.PARAMS

Process gain tables in DATA.PARAMS

Process up/down table sizes.

Typically these top-level subroutines incorporate the steps

delineated in the following algorithm, depending on the type of data being

processed:

PRXXXX (Process data type XXXX)

Initialize - Write the input and binary echo report

subheadings; initialize the control and table data

Get the next needed key from the program key storage tables

2-5
Read through the sequential input file until the record(s)

with the needed key are located. If any are not located,

report the error

Write the input report entries to OUT.RPT

Resolve data overrides from the tabled overrides

Put the referenced keys into the program key storage

tables, returning indices

Perform data lookups, conversions, edits and verifications,

while reporting any errors which occur

Table the data required by program P2 with all overrides,

indices,m and edits

Continue the above subprocesses until all the needed data

are located, reported, edited, and tabled

Skip to the end of the data of type XXXX in the parameter

input file

Write the binary data needed for program P2 and the

corresponding binary echo report records from tabled data.

Below we list and summarize the Program 1 subroutines and their

calling hierarchy. The subroutines are listed in two sections. The first

section presents a hierarchicaral listing of the highest level subroutines.

The listing shows the flow of processing but does not list or describe the

"tool" subroutines. These subroutines perform various housekeeping functions,

but do not participate in the logic flow of Program 2. These subroutines are

listed below the higher level subroutines. Each subroutine is documented more

fully in section II-E of the SOUPS Programmer's Manual.

Main - Drives Program 1

2.1 INIT - Initializes constants and tables

2.2 PRCTL - Process Control Cards

3.1 PRNCTL - Process P2 to P5 Control Cards

2.3 PRSCEN - Process Scenario and Description

3.2 PRSCDS - Process Scenario Description

2.4 PRRARC - Process RARC Parameters

2.5 PRSERV - Process Service Area

2-6
3.3 RRSERV - Read and Report Service Area Cards

3.4 PRPATH - Process Up and Down Path Data

4.1 PPRTOV - Process point overrides

2.6 PRCHAN - Process Channelization Cards

3.5 RDCHNZ - Process Channelization Cards

3.6 RDCHF - Process Channel Family Records

3.7 WBCHAN - Write Channelization Data

2.7 PPROT - Process Protection Ratio Templates

3.8 RRPROT - Read, Report and Template Protection Ratio Tables

3.9 WBPROT - Write Protection Ratio Tables

2.8 PRPNTS - Process point set input cards

3.10 RDPSET - Process needed point set

3.11 RDPNTS - Process needed points

3.12 WBPNTS - Write point set tables

2.9 PRBEAM - Process Ellipse Input and create Ellipse Table

3.13 RDBEAM - Read, Report and Table Beam Data

2.10 PRANT - Process Antenna Input and create Tables

3.14 RDANT - Read and Report needed Antenna records

2.11 PR6AIN - Process Gain Tables

3.15 RR6AIN - Read, Report and Store needed Gain tables

4.2 RRGRTI - Read, Table, and Report Gain Record Type 1

4.3 RRGRT2 - Read, Table, and Report Gain Record Type 2

3.16 WBGAIN - Write Gain Tables

2.12 PRSIZE - Process and Write Up and Down Table Sizes

2.2.2 Program 2

Program P2 converts all the variables to units suitable for use in

Program P3, does all the intra-system calculation involving each service area

at a time, and checks for errors.

The program performs the following functions:

• Transforms all ground and satellite positions from latitude and

longitude to earth-centered Cartesian coordinates.

2-7
• Converts all values expressed In decibels to numerical values

where necessary.

• Reads the control and table files and, after necessary

conversions, writes them out for use by Program 3.

• If the user desires, prints a graph of gain as a function of

off-axis angle for each antenna gain table used in the run.

• Produces extensive diagnostic output at the user's option.

• Checks for errors in the data, prints warnings when an error is

found, and sets the stop code to values depending on the

seriousness of the error.

• Calculates the on-axis gains and beamwidths of all antennas.

• Calculates the basis vectors of the antennas, and the

orientation angle of the beam major axis in the beam plane. The

orientation angle may be specified directly as an input or by

use of a reference point latitude and longitude.

• Calculates transmitter power if the user has specified EIRP,

receiver C/N or impinging PFD as input. Antenna noise

temperature can be specified as an Input or determined from an

input figure of merit (G/T).

• Calculates on-axis beam unit vectors.

• Calculates a nominal wavelength for each assigned channel family

and relevant interference categories (e.g., co-channel, upper

adjacent) between channel families. Checks to ensure the RARC

channelization parameters have not been violated.

2-8
• Calculates the protection ratio for each interference category

using the selected template.

t Writes out all the data needed by Program 3.

The calling hierarchy of the subroutines in Program 2 is listed

below. Each routine is called by the last preceding subroutine of the next

(numerically) lower level.

MAIN - Drives Program 2

1.1 IMIT - Initiates constants and I/O Unit numbers

2.1 CTBLRW - Drives reads and writes, of control and tables

3.1 RWCNTL - Reads and writes control tables

3.2 RWSNRA - Reads and writes scenario data

3.3 RWSNDS - Reads and writes scenario description

3.4 RWRARC - Reads and writes RARC Parameters

3.5 RWSVA - Reads and writes service area data

3.6 RDPRAT - Reads protection ratio template

3.7 RDBEAM - Reads beam tables

3.8 RWANT - Reads and writes antenna tables

3.9 RWGTBL - Reads and writes gain tables

3.10 RWGETB - Reads and writes gain entry table

4.1 PRGRA - Print graphs of gain table

5.1 GAINA - Calculates off-axis antenna gains

3.11 RWRATN - Reads and writes rain attenuation tables

3.12 RUTBSZ - Reads and writes up/down table sizes

1.2 TPATH - Drives reads, calculations and writes of Path and Point data

2.2 RDPATH - Reads Path related data

2.3 RDCHNL - Reads, converts, and edits channel data

3.13 INCAT2 - Calculates nominal frequencies and interference

category tables

2.4 GENPRT - Calculates Protection ratios

3.14 CPRAT - Interpolates protection ratio templates

2.5 PRPTH - Process path related data

2-9
3.15 POSITN - Finds satellite Cartesian Coordinates

3.16 POSITN - Finds aimpoint Cartesian coordinates

3.17 RANGE - Finds satellite on-axis beam

3.18 ORIENT - Drives Orientation angle calculation (for

non-circular satellite antennas)

4.2 ELPSE - Sets Ellipse orientation angle

5.2 LATLON - Finds reference point antenna coordinates

5.3 ELTLN - Finds orientation angle reference points

5.4 TRNFRM - Finds antenna beam plane base vectors

3.19 BMWGOA - Finds on-axis gain of satellite antennas

3.20 POWER - Finds satellite transmitter power

2.5 WRFRBW - Writes nominal wavelength and interference category

tables

2.6 WRPRAT - Writes protection ratio ratios

2.7 RWPST - Reads and writes end point table

2.8 RWPOIN - Reads, calculates and writes ground point data

3.21 POSITN - Finds Cartesian coordinates of earth stations

3.22 BMWGOA - Finds earth station on-axis gains and antenna

beamwidths

3.23 RANGE - Finds earth station on-axis beams

3.24 POWER - Finds earth station transmitter powers

4.3 RPWCN Finds Received power for C/N and PFD calculations

5.5 RANGE - Finds earth-station-satellite range

5.6 PHIS - Finds satellite antenna off-axis angles

5.7 SIGMA - Finds relative orientation angle

5.8 GAINA - Finds off axis antenna gains

5.9 PHIS - Finds elevation angle

5.10 ATTENU - Finds rain attenuation

5.11 GNEQU - Finds equivalent gain

2.9 WRPATH - Writes path related data

2.2.3 Program P3

4

Program P3 reads the user-specified non-interference matrix (i.e.,

specification of interference interactions to be disregarded) and then

performs the following inter-system calculations:

2-10
• For each satellite vs. ground point

Looks up the interference category (e.g., co-channel,

upper-adjacent).

Does no calculations where the channels are non-Interfering

(e.g., channel separations greater than second adjacent

channel).

Does no calculations when the interference matrix specifies

inhibition of interference between the service areas.

At the user's option, does no interference calculation for

same administration, same satellite position, same channel

family.

Calculates slant range, off-axis angle and orientation

angle relative to the major axis of the ellipse.

Calculates the co-polarized and cross-polarized transmit

and receive antenna gains using the selected gain tables.

Calculates the equivalent gain, rain attenuation and

received power.

Allows the user to specify up and down parameters (e.g.,

frequency, channelization) independently.

For up calculations only

Determines the weakest feederlink transmitter (FIT) in the

satellite's own ground point set to determine carrier power

and the strongest FLT's in the other ground point sets to

determine the interfering powers for use in the

carrier-to-interference calculations.

2-11
• For both up and down

Sums all the interference powers taking grouping into

account.

Calculates the carrier to interference power ratio ratios

and interference margins for all the interference

categon'es.

Determines the worst interfering service areas in all five

interference categories.

Produces summary reports for up, down, and total aggregate

interference.

Writes all inputs, intermediate results and final results

to a binary file for use by a report generator.

The calling hierarchy of the subroutines in Program 3 is listed

below. Each routine is called by the last subroutine of the next higher lower

level.

Main - Reads interference matrix and drives Part 3

1.1 INIT - Initiates constants and I/O

2.1 CTBLRW - Drives reads and writes control tables

3.1 RWCNTL - Reads and writes control tables

3.2 RWSNRA - Reads and writes scenario data

3.3 RWSNDS - Reads and writes scenario description

3.4 RWRARC - Reads and writes RARC parameters

3.5 RWSVA - Reads and writes service area data

3.6 RWANT - Reads and writes antenna table

3.7 RWGTBL - Reads and writes gain tables

3.8 RW6ETB - Reads and writes gain entry table

3.9 RWRATN - Reads and writes rain attenuation tables

3.10 RWTBSZ - Reads and writes up/down table sizes

1.2 UP - Drives uppath calculations

2-12
2.2 READIN - Drives reads of path and point related data

3.11 RDPSD3 - Reads path related data

3.12 RWFRBW - Reads and writes interference category and nominal

wavelength tables

3.13 RWPRAT - Reads and writes protection ratios

3.14 RWPST - Reads and writes endpoint tables

3.15 RDPOIN - Reads point set data

2.3 INIT3G - Initializes aggregate interference results

2.4 INIT3P - Initializes cross calculation results

2.5 CHKCRD - Checks if maximum Phi/PhiQ is exceeded

2.6 RPOWER - Finds received power relative to one watt transmitter

power

3.16 RANGE - Finds slant range

3.17 PHIS - Finds off-axis angle for earth antenna

3.18 SIGMA - Finds relative orientation angle

3.19 PHIS - Finds off axis angle for satellite antenna

3.20 GAINA - Finds off axis antenna gains

3.21 PHIS - Finds elevation angle

3.22 ATTENU - Finds rain attenuation

3.23 GNEQU - Finds equivalent gain

2.7 BSTWST - Selects feederlink to be used in interference

calculations

2.8 WRSLTS - Writes intermediate cross calculation results

2.9 WRTAGU - Prints up aggregate interference report

3.24 ERLOC - Calculates Earth station Latitude and Longitude

1.3 DOWN - Reads point data and drives downpath calculations

2.10 READIN - Drives reads of path and point related data

3.25 RDPSD3 - Reads path related data

3.26 RWFRBW - Reads and writes interference category and nominal

wavelength tables

3.27 RWPRAT - Reads and writes protection ratios

3.28 RWPST - Reads and writes endpoint tables

2.11 INIT3P - Initializes cross calculation results

2.12 CHKCRD - Checks if maximum Phi/PhiQ exceeded

2.13 RPOWER - Finds received power relative to one watt transmitter

power

2-13
3.29 RANGE - Finds slant range

3.30 PHIS - Finds off-axis angle for earth antenna

3.31 SIGMA - Finds relative orientation angle

3.32 PHIS - Finds off-axis angle for satellite antenna

3.33 GAINA - Finds off-axis antenna gains

3.34 PHIS - Finds elevation angle

3.35 ATTEND - Finds rain attenuation

3.36 GNEQU - Finds equivalent gain

2.14 WRSLTS - Writes intermediate cross calculation results

2.15 WRTAGD - Prints down aggregate interference report

3.37 ERLOC - Calculates Earth station Latitude and Longitude

2.16 WRATGT - Prints total aggregate interference report

3.38 ERLOC - Calculates Earth station Latitude and Longitude

2.3 HARDCOPY AND BINARY OUTPUTS

Each of the programs produce various hardcopy and binary outputs, as

summarized below:

There are two types of outputs from Program 1:

a Formatted reports echoing the card image inputs and the

binary outputs

• Binary outputs to Program 2

Specifically, the outputs of Program 1 are:

• OUT.RPT - Formatted report echoing the selected card image

inputs, with error messages to assist in debugging the

data, including:

- Control Data - Antenna Characteristics

- Scenario Level Data Table

- Scenario Description - Gain Table

- RARC Parameter - Gain Entry Table

- Protection Ratio - Up/Down Table Sizes

2-14
Template Table

- Protection Ratio

Entry Table

- Beam Table

• OUT.B.UP and OUT.W.UP

• OUT.B.DOWN and OUT.U.DOWN

f

Binary outputs for Program 2 and their corresponding

formatted reports for up/down dependent data including:

- Feeder!ink/Downpath Table

- Channelization Table

- Channel Family Table

- Channel Table

- Point Set Table

- Points Table

Each of the report outputs is discussed in detail in Chapter 4 of the

SOUPS Version 3.4 User's Manual5.

There are three types of outputs from Program 2:

• Hardcopy diagnostic outputs

Hardcopy error message outputs

• Binary outputs to Program 3

Specifically the outputs of Program 2 are:

• P2.IERUNT - A formatted report containing messages to warn

the user of errors in the input data

• P2.IOIAG - A formatted report containing diagnostic output

requested by the user

• P2.IOUTBN and P2.IOUTB2 - Binary output for Program 3

containing all control and data variables.

2-15
The error messages and gain table graphs are described in detail in

5

Chapter 4 of the SOUPS Version 3.8 User's Manual . Chapter 4 of the

Programmer's Manual describes the P2.IDIA6 outputs.

There are four types of outputs from Program 3:

• Hardcopy diagnostic outputs

t Hardcopy aggregate interference summary reports

• Hardcopy detail reports

• Binary outputs for yet-to-be-defined report generators.

Specifically, the outputs from Program 3 are:

• P3.IDIA6 - A report containing the diagnostic output

requested by the user

• P3.IAG61 - The aggregate interference summary reports for

up and total interference

• P3.IAGG2 - The aggregate interference summary report for

down interference

• P3.IRPT1, P3.IRPT2, P3.IRPT3 - Detail reports giving the

detail results of each link equation calculation. The

last, P3.IRPT3, is only written for scenarios using grouping

• P3.IOUTBN - Binary output for use by report writing

programs containing the results of the link equations.

Program 3 outputs are fully documented in Chapter 4 of the SOUPS

Version 8 User's Manual ; P3.IDIAG in Chapter 4 of the Programmer's Manual.

2-16
2.4 TECHNICAL CAPABILITIES

The SOUPS Version 3.8 system can handle aggregate interference

calculations involving up to 300* service areas, with up to 2400* FLTs and

2400* ESRs.

The FLTs and ESRs can be allocated to the service areas in any manner

except that no one area can have more than 50 ESRs and 50 FLTs. A service

area may be totally independent of the others, or sets of service areas may be

combined into groups which may, at a later date, coordinate their system

characteristics to assure compatibility. Grouping is described in Section

VIII.

Calculations for up and down interference are totally independent so

that a service area may have different channelizations, satellite positions

(for possible future implementation of intersatellite links), satellite

antenna ellipses, polarizations, and ground point sets for up and down. If

both up and down interference are calculated in the same run, the aggregate

results are totalled.

2.5 TECHNICAL PROCESSING SEQUENCE

First all calculations involving only one service area are done in

SOUP5 Program 2. These include:

Antejina on-axis gains

Transmitter power

Antenna beamwidth

Channelization, nominal wavelength and interference

categories

Protection ratios

Satellite elliptical antenna beam base vectors, and ellipse

major axis orientation.

*Numbers can be changed on Implementation.

2-17
Next, in Program 3, all Inter-system calculations, (i.e., those

calculations involving more than one service area) are done. The order in

which each pair of service areas is processed differs between the up and down

calculations, as explained below, but the sequence of the inter-system

calculations is the same, and is the following:

Initialize all computed outputs to default values.

Set interference categories. If the two service areas have

non-interfering channelizations, no further inter-system

calculations are done.

If the interference matrix (an input) indicates no

interference should be considered between the system, no

further calculations are done.

Calculate slant range. If the satellite and the ground

point are over the Earth horizon from each other by more

than a distance HORIZ (an input parameter), no further

calculations are done*.

Calculate satellite and ground antenna off-axis angles.

Pointing tolerances are incorporated in such a way as to

minimize the C/I power ratios.

For satellite elliptical antenna beams, calculate the

relative orientation angle between the ellipse major axis

and the projection of the ground point in a plane

orthogonal to the antenna beam.

Calculate satellite and earth station antenna gains.

Calculate earth station antenna elevation angles.

*TF a ground point itSR or FLU is over the horizon from its own satellite,

the user is warned and the calculation continues. No valid results (i.e. not

involving the over-the-horizon points) are affected.

2-18
Calculate rain attenuation and depolarization.

Calculate equivalent link antenna gain.

Calculate received power.

Increment total Interference.

Uplink inter-system calculations are done in the following sequence:

• Fix on one satellite.

• Calculate the received power from all FLTs in its own

service area (carrier power).

• In reality only one carrier FIT can transmit on a given

channel at a time, so we choose which one to use as follows:

If the FIT transmitter power is set directly as watts,

or calculated from a desired EIRP, the FIT yielding

the weakest received power is selected. This is

consistent with SOUP's worst-case-analysis design.

If the FIT transmitter power is calculated from a

desired PFD or C/N, then the received power from all

FLTs will be equal unless the rain attenuation at one

or more FLTs exceeds the allowable rain margin (an

input value). In this case, the received power from

these rain-limited FLTs will be less than that needed

for the desired C/N or PFD. We disregard these FLTs

and assume the faded threshold carrier-power level for

the desired signal.

If the FLT transmitter power 1s set from desired PFD,

we use the strongest received power as the carrier.

2-19
• From each Interfering service area we calculate the

received power from all FLT's under clear sky conditions

and designate the strongest signal as the interference from

that service area.

• The signal from the satellite's own carrier FLT is also

incremented into the total interference in all appropriate

non-cochannel categories.

a After summing all the uplink interference into one

satellite, go on to the next satellite.

The downlink processing sequence is as follows:

• Fix on one Earth Station Receiver (ESR).

• Calculate the received desired signal power from the

satellite under faded conditions and designate this as the

earner.

• Calculate the received interference power from the other

satellites and increment the power into the total

interference. Also increment any non-cochannel signal from

own satellite into the total interference.

After all the inter-system calculations are done for each satellite

(for up) or ESR (for down), the interference powers are summed separately in

co-channel, upper and lower adjacent and second adjacent channel categories

before calculating aggregate interference.

Details of the calculations summarized above are given in Section III

through VIII.

2-20
2.6 TECHNICAL OPTIONS

The SOUPS system gives the user a large number of calculation and

input options. These are described in detail in the SOUPS Version 3.8 User's

5

Manual but those relevant to this document are shown below. In parentheses

after each item is a note showing where in the input data the option is

specified. Further details on each specification can be found in Chapter 4 of

the User's Manual.

Calculations in a run may be made for up only, down only,

or both. In the latter case, total aggregate interference

is calculated. (Record 1 of Control file)

Transmitter power may be specified directly or it may be

set indirectly by EIRP, by Power Flux Density (PFD) at the

input to the receiving antenna or by carrier to noise ratio

(C/N) at the output of the receiving antenna. (Records 2,

5-3, 5-5, and 5-7 of Data.Scenario. If C/N is specified,

noise temperature can be specified directly, or as the

figure of merit (G/T). A maximum rain margin to be used in

the C/N and PFD calculation may also be specified. See

Section VI for details. Antenna noise temperature is set

in the antenna section of the parameter file. Maximum rain

margin for up calculations is set in Record 2 of the

scenario file. For down, the maximum rain margin is set in

Record 3 of the RARC section of the parameter file.)

Gain fall-off at the satellite beam edge (Delta-G) is

specified for the whole scenario but can be overridden at

the service area level. (Records 1, 5-3, and 5-5 of

Data.Scenario, and Record 1 of RARC section of parameter

file.)

Earth station antenna pointing tolerance is specified in

units of the antenna beamwidth. (Records 1, 5-3 and 5-5 of

Data.Scenario and Record 1 of RARC section of parameter

file.)

2-21
Satellite antenna pointing error is specified as an angle.

(Records 1, 5-3 and 5-5 of Data.Scenario and Record 1 of

RARC section of parameter file.)

Antenna aperature efficiency is specified for each

antenna. (Antenna Record of Data.Params.)

Antenna gain patterns may be specified in a number of

ways. See Section IV for details. (Antenna and Gain

Pattern section of Data.Params.)

The nominal frequency used for all calculations, can be set

to the lowest, highest or median channel center frequency

of a family. (Record 3 of Data.Scenario.)

Peak-to-peak deviation, bandwidths, noise bandwidths and

top baseband frequency may be specified. (Channelization

section of Data.Params.)

Protection ratio curves for non-cochannel situations can be

specified. (Protection Ratio section of Data.Params and

Record 1 of Scenario file.)

Group assignment can be specified. See Section VIII for

details. (Option to use grouping on record 3 of Scenario

file. Individual group assignments on Record 5-1 of same

file.)

For non-group assignment runs the user may choose not to

include any interferer with the same administration code,

satellite longitude, and channel family. (Record 3 of

Data. Scenario.)

The user may request that no interference be calculated if

the Phi/Phi0 for either antenna is greater than an input

value (Record 3 of Data.Scenario)

2-22
Through the use of a non-interference matrix, the user can

inhibit interference calculations between any two service

areas in either direction. (Interference matrix file.)

Circular or linear polarization can be specified, along

with the polarization angle (linear) or handedness

(circuclar). (Record 2 of Data.Scenario for

circular/linear; Records 2, 5-3 and 5-5 of Data.Scenario

for angle.)

The percent of worst month number is specified for the rain

attenuation calculations. (Record 1 of Data.Scenario.)

The user may choose to include or not to include rain

attenuation in the received power calculation. (Record 2

of Data.Scenario.)

The polarization reference point may be set at either the

subsatellite point or the satellite antenna aim poinmt

(only relevant when using rain attenuation with linear

polarization). (Record 2 of Data.Scenario.)

The user may specify calculation of interference into one

specific channel only. (Record 3 of scenario file.)

The user may request the SOUP only calculate interference

into a selected set of service areas. (Records 9-11 of

Data.Control.)

2-23
III. GEOMETRY

3.1 COORDINATES AND POSITIONS

In order to minimize the use of trigonometric functions (which slows

the computations), all satellite and ground positions are transformed to

Earth-centered Cartesian coordinates by subroutine POSITN in Program 2. Below

is a table defining the geocentric axes in terms of the longitude and latitude

of their intersection with the Earth's surface.

AXIS INTERSECTION OF AXIS

X 0° Latitude 90° E Longitude

Y 0° Latitude 0* Longitude

Z 90° N Latitude

All distances are measured in Earth radii, defined as 6.3782 x 10

7 8 meters. ' We assume the earth is spherical, that is all ground points are

1 earth radius from the center. All satellites are placed 6.6105 earth radii

g

from the Earth's center (nominal geostationary orbital height) . Both the

latitude and longitude of the satellite are set by input values. The

transformations are done using the following equations:

X = R Cos e Cos 0 3-1

Y = R Cos e Sin 0 3-2

Z = R Sin e 3-3

3-1
where

e is North Latitude

0 is East Longitude

R is 1 for ground points, or 6.6105 for satellites.

3.2 RANGE

The range between two points denoted by their position vectors

is

Pl = <Plx' Ply> Plz> and P2 - <P2x' P2y' P2z>

? ? ?

RR — (P P \ +• (P P \ + IP P } 12

 = (P2x " Plx} (P2y ~ Ply} (P2z " Plzj

3-5

The unit range vector between the two points is

R12

 = (P2 " P

l

)

 ' R12

 3

~

6

The on-axis beam unit vector for an antenna is R = R,~ where the antenna is

at P, and the aim point is at P«. Satellite antennas are "aimed" at their

beam aimpoint with some specified tolerance. Earth station antennas are "aimed"

at their own satellite with a specified tolerance.

These range calculations are done using subroutine RANGE.

3.3 OFF-AXIS ANGLES

The antenna off-axis gain angle, 0, towards an interference victim is

found by subroutine PHIS in the following manner.

0 = Cos"1 (RQa • . R12) 3-7

where Rrt, is the unit on-axis beam vector mentioned above and R10 is the unit oa 12

range vector between the two antennas.

3-2
Desired signal power at the satellite assumes the full earth station

antenna mispointing. Before the off-axis angle is used for gain calculation,

the pointing errors are introduced to decrease the carrier-to-interference

power ratio (C/I) to the worst-case extent. The earth station antenna

pointing tolerance is specified in beamwidths.

The satellite antenna pointing error is a direct input and the full

pointing error is included in desired signal calculations. For interference

signals the error is subtracted from the off-axis angle (worst-case).

However, if the pointing error to be subtracted is larger than the off-axis

angle, the off-axis angle is set to 0.

3.4 ELEVATION ANGLE

The elevation angle of the satellite as seen by the earth station

antenna is computed as follows:

*el

 =*g * n/2' 3~8

where 6 is the angle between the ground point position vector and the

ground antenna on-axis vector, as found by subroutine PHIS.

3.5 ELLIPSE ORIENTATION

In order to find the relative ellipse orientation, the following

steps are taken:

1. The antenna beam plane base vectors are calculated (see

definition below)

2. The orientation of the ellipse major axis relative to the X base

vector are calculated.

3. The orientation angle of the vector (in the beam plane)

connecting the beam aim point and the X projection of the ground

point into the plane is calculated relative to the base vector.

3-3
4. The difference between the two orientation angles calculated

above (steps 2 a 3) is used for the satellite antenna gain

calculations.

The present implementation of this algorithm in SOUPS uses code from

SOUP3 for the above calculations. This adds complications, because the

definitions of the antenna beam base vectors, and consequently the values of

the ellipse orientation angle, differ between those used for input, and those

used for internal computation. The final value of a, which is the difference

between two angles, is not affected by the choice of base vectors.

Before going into more detail, it is necessary to give some

definitions, below.

• Antenna beam plane (cross section).

A plane orthogonal to the satellite antenna bn-axis beam center

passing through the beam aim point (which is on the Earth's

surface).

Note: not to be confused with Antenna Plane.

• Antenna beam coordinate system.

A coordinate system with its origin at the beam aim point.

Units are unimportant, because these coordinates are used only

to calculate angles.

*

System used for internal computation (Internal system)

The Y-axis is defined by the orthogonal projection of

the subsatellite point on the antenna beam plane.

System used for input (Input system)

The Y-axis is defined to be parallel to the

intersection of the antenna beamplane and Earth's

equatorial plane. This is the system used by the SOUP

user community. In both systems, the X-axis is the

beam on-axis vector, and the unit vector along the

Z-axis is defined as Z = X x Y (vector cross product).

3-4
t Orientation angle.

The angle between a vector in the antenna beam plane and the

Y-axis of the antenna beam coordinate system. The orientation

angle of a ground point refers to the orientation angle of a

vector connecting the origin and the satellite ray projection of

the ground point on the plane.

• Antenna plane.

A plane orthogonal to the line connecting the antenna (i.e.,

satellite) to the center of the Earth.

Note: not to be confused with Antenna Beam Plane.

• Antenna coordinate system.

A two-dimensional coordinate system in the antenna plane, with

its origin at the subsatellite point, and its X-axis defined to

be parallel to the intersection of the antenna plane and the

Earth's equatorial plane and its Y-axis perpendicular to the

X-axis. Distance is measured in radians, as seen from the

satellite.

The user may specify the elliptical antenna beam orientation in one

of the two ways:

1. Orientation angle in the coordinate system used for input.

•

2. Ellipse reference point; the latitude and longitude of an

arbitrary point on the ellipse major axis' projection on the

Earth's surface (except the beam aim point).

If ellipse orientation angle is given, it is translated into the internal

ellipse orientation angle. The method is implemented because it uses existing

proven code.

The first step is to use subroutine LATLON (called by ELPSE) which

finds the antenna plane coordinates of the beam aim point using the following

algorithm.

3-5
SX = Tan'1 (Cos (QC) * Sin ($c - *s) / 3-9

(Rs - Cos (»c) * Cos (0C - 0S)))

SY = Tan'1 (Sin e /

(Cos2 (e) * Sin2 (tf - A ) + (Re - Cos (* ) * c c s s c

Cos (0c - *s))2)

1/2) 3-10

Where

0 s satellite longitude

0 = beam aimpoint longitude

9 = beam aimpoint latitude c

R = geosynchronous orbital radius in earth radii

SX = the X coordinate of the satellite ray projection of the

aimpoint on the antenna plane

SY = the Y coordinate of above.

All coordinates are in units of angle between the point in the antenna beam

plane and the origin as seen by satellite.

Next subroutine ELTLN is used to find the X and Y distances from the

beam axis SX2, SY2, in the antenna plane, of a reference point on the ellipse

major axis, one half semimajor axis from the beam aimpoint.

SX2 = (Araaj/2) * Cos (e) 3-11

SX2 = (Amaj/2) * Sin (e) 3-12

Where

A . is the ellipse major axis (in radians)

e is the ellipse orientation angle as specified by the user

Using the numbers, SX, SX2, SY and SY2, subroutine ELTLN finds a reference

point of the ellipse major axis, using the following methods. First, it finds

a reference point in the antenna plane

3-6
XI = SX + SX2

Yl = SY + SY2

then it calculates

T = R * Sin (Cos'1 (Cos (XI) * Cos (Yl))) 3-13

If T > 0, (i.e., the reference point does not intersect the Earth

surface), XI is reset to SX - SX2 and Yl is reset to SY - SY2; that is, the

reference point is placed on the other side of the ellipse major axis.

If after reseting the reference point to the other half of the

ellipse major axis T is still > 1, an error exists, the ellipse aimpoint does

not intersect the earth. Subroutine ELTLN prints an error message and sets

the Program 2 Stop code to a level which warns that Program P3 will not work.

Assuming no error, the calculations continue.

PX = Sin'1 (Sin (Yl)/Sin (Cos'^CosUl) Cos(Yl)))) 3-14

If XI < 0, PX = v - PX

D = Sin"1 (T) 3-15

BLAM = D - Cos"1 (Cos (XI) Cos (Yl)) 3-16

er = Sin"1 (Sin (BLAM) Sin (PX) ) 3-17

Where e = the reference point longitude

AL = Cos"1 (Cos(BLAM)/Cos ef) 3-18

If PX >ir/2, AL = -AL 3-19

t = tf + AL 3-20

This will not happen with a valid ellipse, but can inadvertently happen

when the satellite position used in the scenario differs considerably from the

satellite position used to generate the ellipse.

3-7
Where i>r = the reference point longitude.

Using the reference point, which was either computed above or entered

by the user, subroutine ELPSE finds the vector connecting the beam aimpoint

and the reference point, (X , , Y , , Zel ). (Later this vector will be

projected onto the antenna beam plane).

3-22

X

elp

Y

elp

Z

elp

= Cos e

= Cos e

= Sin e

r

 * Cos 4>r

r

 * Sin j>r

r ~ beam

~

 Xbeam

_ Vbeam

Xbeam' Ybeam' Z = ^ CarteSlan coord1nates of tne beam

Where

o s latitude of reference point

0 = longitude of reference point

am'

 Ybeam

aimpoint.

Subroutine TRNFRM then finds the internal base vectors and the

orientation angle of the ellipse in the antenna beam plane. The three vectors

are defined as:

A, = Parallel to beam axis

A2 = The line running through the origin and the satellite ray

projection of the subsatellite point on the antenna beam

plane. (This is the Y axis in the antenna beam plane)

A- = A. x A« (vector cross product) (This is the Z axis in the

antenna beam plane)

A, is not computed as we only need to know angles in the antenna

beam plane, not perpendicular to it. The three components (in Earth centered

Cartesian coordinates) of the two vectors A2 and A3 are computed by

3-8
Tan 9 = Sin (w) / (R - Cos w)

Cos w = Cos (ec) * Cos (e$) * Cos (#s - 0c) + Sin (QC)

* Sin (es)

Sin a .= Cos (ec) * Sin (4>c - 0g) / sin w

A2X = -Cos (a) * Sin (0$) + Sin (a) * Sin (-e$) * Cos (as)

2Y = Cos (a) * Cos («5) + Sin (a) * Sin (-e) * Sin

A2Z = Sin (a) * Cos (9$)

A3X = Sin (e) * Cos (0$) * Cos (e$) + Cos (e) * Sin (a)

* Sin (tfs) + Cos (&)

A^v = Sin (©) * Cos (ij * Sin (0 ) - Cos (e) * Sin (a) j T o •>

* Cos (0 ) + Cos (e) * Cos (a) * Sin (-e ) * Sin (A )

s s s

A3Z = -Sin (e) * Sin (-e$) + Cos (o) * Cos (a) * Cos (»s)

Here, » and e are the latitudes of the satellite and the

satellite antenna aimpoint with the surface of the earth, respectively; 0

and 0 are the corresponding longitudes, and R is the radius of the

geostationary orbit in earth radii.

The orientation angle of the ellipse is computed by subroutines

TRNFRM and ELPSE

ORAN1 = Tan'1 ((A3 . Re]p) / (Ag . Relp)) 3-24

Where R , = (X -| , Y , , Z -, ) is the vector connecting the beam aimpoint and the ellipse reference point.

In Program 3, subroutine SIGMA calculates the relative orientation

angle using the following computation.

a = Tan"1 ((A3 . R12) / (Ag . R12)) - ORAN1 3-25

The calculation of the elliptical antenna beamwidth at a relative ellipse

orientation is:

06 = Cos2a + AXR * Sin2a 3-26

3-9
where AXR is the axial ratio of the antenna. The beamwidth used in the gain

calculations in subroutine RPWCN (Program 2) and RPOWER (Program 3) is

where A is the beamwidth used for gain calculations, and K . is the z maj

major axis beamwidth.

3-10
IV. ANTENNA GAINS

4.1 BEAM WIDTH

The user may characterize an antenna either by a diameter (earth

station antennas only), or by a beamwidth (ground or satellite antennas).* In

the case of an elliptical antenna beam (satellite only) both the major and

minor axis beamwidth are specified. The satellite beamwidth is specified for

a coverage area edge gain contour of AG dB down from mainbeam gain.** SOUPS

converts all satellite's beamwidths to a 3dB beamwidth by the following formula

All ground station antenna beamwidths must be specified as half-power

beamwidths.

If diameter is specified, half-power beamwidth is calculated by the

following formula.

6 = (223/180) * (x/D) 4-2

Antenna diameter or beamwidth are set in the Antenna Section of the

parameter file.

**AG can be set in record 1 of the RARC section of the parameter file, or

records 1, 5-3 and 5-5 of the scenario file.

4-1
where £_ is the antenna half-power beamwidth in radians, x is the nominal

wavelength in meters (see Section VII), and D is the antenna diameter in

meters. This is equivalent to the CCIR value of 21.28/fD degrees where f is

Q

the frequency in 6hz.

4.2 ON-AXIS GAIN

The on-axis gain of an antenna is calculated by subroutine BMWGOA as

G = EAP( (»/*)' (223/180) )2 AXR 4-3

061 2

where G = the numerical on axis gain

oa

= 6 is the beamwidth in radians (see Eq. 4-1 above)

= AXR is the voltage axial ratio of an elliptical antenna (for

elliptical antennas <b is the major axis beamwidth) ,

= EAR is the antenna aperature efficiency.

4.3 OFF-AXIS GAIN**

The off-axis gain is given by

G = G 10~>lf 4-4

oa

where G is the numerical off-axis gain; G is the numerical on-axis gain; Ou

and f, the discrimination or gain fall off (dB), is discussed below.

SOUPS allows the user to specify the use of any number of antenna patterns in

terms of five gain pattern types, designated types 1, 2, 3, 4 and 5. Two of

the types, 2 and 3, were not used at RARC-83 and are not considered here.

(They are kept as an aide to users who have not yet converted their data to

current gain patterns). The five types are listed below:

Antenna beam major and minor axes are set in Antenna section of parameter

file

**Antenna gain types are specified in the Antenna section of the parameter

file, and defined in the Gain Table section of the same file.

4-2
- Type 1 - Segmented gain pattern.

- Type 2 - A special case of type 1.

- Type 3 - 1982 Fast Rolloff Satellite Antenna.

- Type 4 - 1982 CPM Feeder! ink (Earth Station) Transmit Antenna

- Type 5 - 1983 RARC Fast Roll off Satellite Antenna

Type 1, which has been used to model many standard and proposed

antenna patterns, allows the user to define f as a composite of any number of

segments. The values of b or i (defined below) delineating the segment a

boundaries are read from the gain entry table section of the data base. The

value of discrimination f in each segment is defined by one of five user

designated functions. The segment types can be used in any combination.

1) f = C1 4-5

2) f = C1 (*a - C2)

C

3 4-6

3) f = C1 + C2 log (C3 (*a - C4) ). 4-7

4) f = C1 + 10 log (GQa) + C2 log (*) + C3 £ 4-8

5) F=C 1 + C 2 ^ a

2 +C3 6a4

-....CnPa

2{n

-

1 )

 4-9

f = -10 log F

where 0 = off axis angle in degrees

t>2 = antenna beamwidth (corrected for ellipse orientation if antenna is

elliptical)

and n (the number of coefficients) and the coefficients C,... C

are taken from the gain entry table section of the data base.

4-3
For each segment, the user specifies the segment limit, whether the

limit is on tf, or £ , the segment equation type (1 to 5) and the values of

the C.'s.

Type 4, the CPM 82 Feederlink Transmit antenna uses a parameter,

D . (minimum antenna diameter in meters), which is entered on the RARC

parameter section of the parameters file. The equation has four segments

which are functions of #, tf, and V a

where V = D/Dmin

and D is the antenna diameter in meters. The equations are shown on the

following page. Various antenna patterns may be modeled by setting the

values of the C. 's appropriately.

4-4
aa

•oegj or «•oCNcat Oi enII O

ca

(0

o

ao

<0

•aaaUL0. OoULJ2J3.5uIc'5a

i

<BC<B

rtj (01

ao»

.2'xa

c a «c "O

'•5 .S

« c c « o en c o 5 ** a

 5 o £ S «

. 5 i 10 «

c w O £ o (0

v/ o

V*• U

v

c5

9 a a

U

— OJ

en o

cr

LU

U-f C3

aOO

U

c

+

 + I

o 6 -xtoE

ua

oa

4-5
The following values of the C. parameters for gain type 4 will produce the

1982 CPM recommended feederlink transmit antenna pattern.

CO-POLARIZED CROSS-POLARIZED

PARAMETER GAIN PATTERN GAIN PATTERN

C] .5 .493

C2 -12. 0.

C3 0. -30.

C4 .635 0.

C5 36. 0.

Cg -20. 0.

C? 36.3 8.91

Cg 45 -999.

Cg -20. 0.

C1Q -12.6 0.

Cn 29. 9.0

C12 -25.0 -20.

c13 -10. -10.

4-6
Type 5, 1983 RARC Satellite Fast Roll-off, has segment boundaries

which are functions of AG and A , which is a function of £,. The segment

a Z

boundaries and equations are shown on the following table.

4-7
.

au0)

I«Mao

ina

9i00

CD

i£

0)aa3

i

OO

nU

4-8
The following values of the C. parameters in Type 5 gives the 83-WARC Fast

Roll-off Satellite Antenna Patte'rn.

CO-POLARIZED

PARAMETER GAIN PATTERN

cx = o.

C2 = .8

C3 = 25.23

C4 = 22.

C5 = 20.

C, 0.

o

4-9
V. RAIN ATTENUATION AND DEPOLARIZATION

5.1 GENERAL DESCRIPTION

The rain attenuation and depolarization subroutine ATTEND which is

documented below is an adaptation of a subroutine developed by J. Royce

Trenholm of Canada. It contains the necessary specific attenuation

coefficients for the 12 GHz downlink and 17 GHz uplinks. As previously

mentioned, the user who wants clear weather margins may deactivate rain

attenuation calculations. It should be noted that atmospheric absorption is

not included in the calculations (RARC-83 Resolution COM 4/1). Even when the

user specifies rain attenuation, the uplink interference (but not desired

signal) is calculated without rain attenuation. The algorithms developed to

estimate the rain attenuation and cross polarization discrimination are

generally based on information contained in the CCIR CPM report, as modified

at RARC-83.

5.2 AVERAGE YEAR AND WORST MONTH STATISTICS

Since the RARC-83 performance criteria were specified in terms of

percent of the worst month that the attenuation will be exceeded (i.e., 1

percent of the worst month at RARC-83)* and the rain rate data given in Study

Group 5 is in terms of annual statistics, the program converts predicted

annual statistics to worst-month based on the following approximate

relationship:

Specified on record 1 of scenario file.

5-1
where P is percent of year and P is percent of worst month. At

RARC-83, an annual rain fade exceedance time percentage of 0.29 was used

independently of the rain climate zone. This is done in subroutine RWSNRA.

5.3 ESTIMATED HEIGHT OF RAIN ABOVE MEAN SEA LEVEL (HR) AND SLANT PATH

LENGTH THROUGH THE RAIN (Lg)

This is based upon the data given in Report 563 and algorithms

modified at the CPM. The heights corresponding to .01 average year exceedance

percent are used:

HR (Km) = (5.1 - 2.15 log1Q (1 + 10 (— ))

t 3

where L = the absolute value of the test point latitude in degrees, and

takes the following values)

P = .6 ' , 0 <_ L < 20°

p = .6 + 0.02 ( L - 20°) , 20° < L <_ 40°

p = 1. , 40° < L

The equations apply to latitudes up to 70°

5.4 SLANT PATH DISTANCE THROUGH RAIN

Once the rain height is determined, the slant path distance is

calculated using the following equation:

Ls = (HR - ho)/(A+ Sin 6)

Where A = (Sin2e + 2 (HR - h ) / R£)

1/2

e = elevation angle at test point

h = height of test point above mean sea level

RE » Effective earth radius (8500 Km)

5-2
5.5 SLANT PATH REDUCTION FACTOR

The slant path reduction factor is determined using the expression:

90 RP =

90 + 4 LS Cos

Where

P = Log,Q (annual Probability (percent))

LS = slant path distance (see step (2))

e = elevation angle of test point.

5.6 SPECIFIC ATTENUATION CORRESPONDING TO THE PARTICULAR CLIMATIC ZONE

The equations used to determine the specific attenuation are as

follows (based on data in Report 721 (Mod F)):

Sa = k(RRa)

k = (kH + kv + (kH - kv) Cos2 (e) Cos (2 t))/2

a = (kH OH + ky * ay + (kH «H - ky <»y) Cos («)

Cos (2 t))/2k

where k = elevation angle at test point

t = polarization tilt angle at test point (see below)

RR = rain rate (mm/hr)

k^j, ky, o^, ay are coefficients which depend on frequency and

spatial rain rate distribution, (subscripts H and V stand for horizontal

and verticle polarization).

For the nominal 12.5 gHz and 17.5 gHz frequencies the coefficient values

were estimated to be:

gHz kH ky H V

12,5 gHz 0.0217 0.019 1.205 1.186

17.5 gHz 0.053 0.516 1.116 1.096

5-3
The rain intensity data for .01 percent of the average year for each

climatic zone RR (mrn/hr) is taken from Report 563-1 Table 1. The

nominal-frequency specific attenuation for the zone for circular polarization is

given by:

• SA = 2.0202 ' 10~2 (RR1'

198) at 12.5 GHz

SA = 5.21 ' 10~2 (RR1*

114) at 17.5 GHz

5.7 POLARIZATION TILT ANGLE

The tilt angle for a vertically defined polarized wave, t, is the angle

the received polarization vector makes with the plane containing the local

vertical and the line joining the earth station and the satellite. It can be

obtained using the following expression: (i.e., for a vertically polarized wave

t=0° when the earth station is at the reference point, i.e., (L, «L = £D, p p K

XR):

t = tan"1 Sln ^R

 cos ^psin ( xp~ XS^ ~cos ^Rsin ( XR~ xs^ sin ^P

sin £Rsin fy> -cos 6R sin ( XR- x$) cos £p sin ( Xp- x$)

where:

XR = latitude, longitude of reference point defining the sense of

polarization. There are basically two alternatives in the selection

of the reference polarization vector:

a) Each beam has its polarization vector rotated so that it appears

parallel to the projection of the local vertical onto the

antenna beam plane at a point within the service area - usually

this point is selected as the aim point (i.e., (&R, XR =

*B»

 XB}

b) The polarization vectors of every beam can be made parallel (or

perpendicular) at the satellite irrespective of the apparent

orientation of the earth stations. In this case XR = x^ and

the equation simplies to:

5-4
t = tan'1 (cot dp sin (x - xg))

Where t , x = coordinates of the earth station (test point)

x = satellite longitude

The user can choose either option a) or b) above at the scenario level.

Note that since the tilt angle value used in Report 721 to determine

specific attenuation coefficients, K, uses the horizontal line at the earth

station as the reference line, the complement of t obtained in the above

expression is used. For circular polarization, t = 45°.

5.8 RAIN ATTENUATION

The RARC-83 rain model applies an 88 percent fade reduction to the

CPM model based on last-minute purported experience/observations.

AtnQ1 = 0.88 (SA) (RP) (Lg)

Then the attenuation for the input average year fade exceedance percentage

(Pan) is calculated by:

A

Atn = C . Atn • (,01/Pan)

Where C and A are set as follows:

C = 1. A = .33 .001 <_ Pan < .01

C = 1. A . .41 .01 <_ Pan < .1

C = 1.3 A = .5 1. <_ Pan < .1

For attenuation exceeded for 1 percent of the worst month, Pan = 0.29 (Section

5.2).

5.9 FREQUENCY SCALING

Since the rain attenuation is estimated at one specific frequency in

the particular band (12.5 GHz or 17.5 GHz), a frequency scaling equation is

used to determine the attenuation for other frequencies in the respective

5-5
bands. The frequency scaling method used is based on the method of Report 564

("this was not endorsed by the CPM, but nevertheless used at RARC-83):

Af = g(f)/g(fR)AR

where:

g(x) = X1'

72/ 1 + 3 x 10~7 (X1*72)2

Af = Rain attenuation at desired frequency, f, (dB)

fD = Reference frequency (12.5 gHz or 17.5 gHz)

K

AR = Rain attenuation at reference frequency (dB)

x = desired frequency (GHz).

5.10 CROSS POLARIZATION DISCRIMINATION

The cross polarization due to propagation through hydrometers (rain

only, atmospheric ice was disregarded) is estimated using the following

general equation:

XPDDB = U - V Log1Q (Af) dB

Where U is estimated by:

U = K2 - 10 log 1/2 (1 - Cos 4t(e~Km )) + 30 log1(J(f)

- 40 log (Cos «)

and

K, K are effective parameters of the raindrop canting angle

distribution. The values used in the program are:

K = 0, K = 0.25° (CPM)

t = tilt angle (=45° for circular polarization.)

e = elevation angle (In the program the upper limit of 60° is

substituted for higher elevation angles and a lower limit

is not observed.)

5-6
V = a constant over the specified frequency range as follows:

20 , 8 gHz < f <_ 15 gHz

23 , 14 gHz < f <_ 35 gHz

Atten = Rain attenuation in dB corresponding to the case for

circular polarization even if linear polarization is

used.

Note that the XPD used in the equivalent gain calculation (see Section 6-1) is

given by XPD = 10"] * XPDDB.

5-7
VI. EQUIVALENT GAIN, TRANSMITTER POWER AND RECEIVED POWER

A. EQUIVALENT GAIN

The equivalent gain is computed using the following antenna

parameters: 1) the earth station copolarized gain, G ; 2) the earth

station cross-polarized gain, G ; 3) the satellite copolarized gain, G ;

y " oo

and 4) the satellite cross-polarized gain, GSX (all gains numerical). The

equivalent gain is given by

G = GI Cos 8 + G2 Sin2e 6-1

Where

Gl • Sgc Gsc + Ggx Gsx + (Ggx Gsc + Gsx>'XPO 6'2

G2 . ( Ggc Gsx + Ggx Gsc)

2 + (Ggc Gsc * Ggx GSX)/XPD 6-3

B is the relative linear polarization of the two linear polarizations

(If both polarizations are circular B = 0° or 90°; if one is

circular, and the other linear, B = 45°)

XPD is (numerical) rain depolarization as defined in the previous

chapter. If the user requests clear weather margins (i.e., no rain

attenuation calculations) the last terms of G-| and G/> are set to

0. Further details on this algorithm are provided in Appendix A.

6-1
6.2 TRANSMITTER POWER**

Transmitter power may be computed in one of four ways:

o Given as an input in Watts

o From desired EIRP

o From required receiver carrier-to-noise ratio (C/N) at the

receiving antenna

2

o From required power flux density (PFD - Watts/m ) at the

receiving antenna.

Below we discuss how SOUP computes the transmitter power in Watts for the last

three options.

If the user specifies the EIRP of the transmitter, Subroutine POWER

calculates the power in the following manner:

P = EIRP/6 6-4 03

where P is the power (in Watts), EIRP is in Watts and G_, is the antenna 03

on-axis gain (numerical). See Section 4.2 for details of GQa.

In order to compute power from desired C/N or desired PFD the link

equation given below is used. For up calculations each possible feederlink

transmitter (FIT) is given its appropriate calculated power.* However, the

satellite (downpath transmitter) power calculations can give a different power

for each earth station received (ESR). SOUP sets the satellite power to the

minimum value required to produce at least the specified PFD or C/N at all

ESRs. This means that all ESRs will receive at least the requested C/N or PFD

unless rain margin limitations (see below) intervene.

*For service areas with more than one possible FIT there is an entirely different problem - which FIT should be used for carrier power and which for

interferer power in the C/I calculations. This problem is discussed in

Section 8.1.

**Specified on Records 2, 5-3, 5-5 and 5-7 of scenario file.
If the user specifies C/N, the following power calculations are

done. First, the receiver system noise temperature may be specified directly

or in terms of the figure of merit (G/T)*. In the latter case, the

temperature is computed as:

T = Gna ID'0*

1 <S'T> 6-5 OQ

where Goa is the numerical antenna on-axis gain, T is the noise temperature

in °K, and (G/T) is in units of dBK. Next the link equation (see Section

6-3 below) is used to calculate RCVPWR-j, the received carrier power divided

by the transmitter power. If the calculated rain attenuation is greater than

the maximum rain margin** then RCVPWR-j is calculated by setting the rain

attenuation value to the user-specified maximum rain margin.

Finally, the transmitter power is calculated as follows:

P = (C/N) * K * T * BW/ RCVPWR1 6-6

Where

P = transmitter power (watts)

C/N = Carrier-to-noise power ratio (numerical)

K = Boltzman's constant (joules/K)

T = Antenna noise temperature (K) (antenna input)

BW = channel noise bandwidth (Hz) (channelization input)

RCVPWR-j = Received power divided by transmitter power (see

below)

If the user specifies the power by the receiver's power flux density

(PFD) the following calculation is done.

P = (PFD)4 TT R2Af/Gtr 6-7

*The antenna key is specified on Records 2, 5-3, 5-5, 5-6 and 5-7 of the

scenario file. The temperature or G/T is specified in the antenna record of

the parameter file.

**The maximum up margin is set on Record 2 of the scenario file. The maximum

down margin is set in Record 3 of the RARC section of the parameter file.

V

6-3
Where

P = transmitter power (Watts)

PFD = user specified PFD (converted to numerical value)

R = slant range (m)

Af = rain attenuation (numerical)

S. = transmitter antenna gain (numerical) in the direction

6.3 RECEIVED POWER

To calculate the received power we use the following formula:

RCVPWR = P . G (x/4TrR)2 / Af

Where

P = transmitter power (watts)

Ge_ = equivalent gain (numerical)

1 = the wavelength (m)

R = slant range (m)

A.p = rain attenuation (numerical); if user requests clear

weather margin, Atn is set to 1.

The calculation of the RCVPWR1 is done in subroutine RPOWER in

Program 3 for use in setting C/I values, and RPWCN in Program 2 to calculate

transmitter power when C/N or PFD is specified.

6-4
VII. CHANNELIZATION AND PROTECTION RATIOS

7.1 NOMINAL WAVELENGTH

The nominal wavelength, x, is the wavelength (in meters) used for all

gain and attenuation calculations. It is given by

C/fnom VIIA1

Where C is the speed of light in meters/nanosecond (= .299796)

and fnom is the nominal frequency (gHz).

At the user's option* fnom is the center frequency of either the lowest,

highest or median channel used by the service area.

7.2 INTERFERENCE CATEGORIES

Each interference interaction is given one of six (6) interference

categories, except between systems in a group or for which the interference

matrix precludes consideration. For treatment of interference category in

grouping, see Section 8.3.

1 = Co-channel interference

2 = Upper adjacent interference

3 = Lower adjacent interference

4 = Next upper adjacent interference

This option is set on Record 3 of the scenario file.

7-1
5 = Next lower adjacent interference

6 = No interference

If the channel assignments of two systems have more than one

category, all categories are used in determining interference. For example, a

system with channels 2, 6 and 10 interfering with a system with channels 6 and

8 will be included in co-channel (6 into 6), next upper adjacent (10 into 8),

and next lower adjacent (6 into 8) interference.

If the scenario contains more than one channelization scheme (i.e.,

there is more than one definition of the center frequency and bandwidth of

each channel), SOUPS cannot make meaningful interference category

assignments. In this case SOUPS sets all interference categories to 1

(co-channel) and warns the user.

7.3 CHANNELIZATION SCHEME (RARC PARAMETERS*)

If the channelization scheme violates the RARC parameters, SOUPS

warns the user. It uses the tests below to check for violations

1. FL - B/2 < RL + GL

2. FL + (N - 1)S + B/2 > R,j - Gy

Where

F. = lowest center frequency in channelization

B = bandwidth of channel

R. = RARC lower bandedge frequency

Ry = RARC upper bandedge frequency

S = separation between channels

N = number of channels

G. = lower guard bandwidth

G.| = upper guard bandwidth.

*The RARC parameter set key is specified on record 1 of the scenario file. The

parameters themselves are in the RARC section of the parameter file.

7-2
The channel bandwidth is an input parameter in the channelization record of the

parameters. All other parameters are inputs in the RARC parameter record.

7.4 PROTECTION RATIOS*

SOUPS allows the user to specify separate protection ratios for

uplinks, downlinks, and total aggregate interference (single entry protection

ratios are not used).

The protection ratios are supplied by the user as a co-channel

protection ratio (PRQ) in dB and a template which gives the fall-off (in dB)

from the co-channel value as a function of normalized frequency offset. The

normalized frequency offset is the frequency offset divided by the Carson's

rule bandwidth (peak-to-peak-deviation + 2 x top-baseband-frequency). For

total protection ratio calculations the Carson's bandwidth of the down

channelization is used. Adjacent channels are typically interleaved and

cross-polarized. If more than one channelization is used in a scenario all

interference categories are set to co-channel and the co-channel protection

ratio is set to 0 dB.

Each template is specified as a series of line segments in order by

increasing upper frequency limit**. Each segment in the template is specified

by four numbers:

• Upper limit, the highest normalized frequency to which this line

segment applies. (This limit is not needed for the last

segment.)

t Segment-value-at-offset. The value (in dB) of the protection

ratio fall-off when the normalized frequency offset equals the

offset (see below)

* The protection ratio template key and the co-channel protection ratios are

specified on record 3 of the scenario file.

**Specified in the Protection Ratio section of the parameter file.

7-3
o Slope. The slope of the line segment in dB/normalizejd-frequencyoffset

o Offset. The frequency offset at which the protection ratio falloff has the value specified by the segment-value-at-offset.

The formula used is:

PR = PR + Segment-value-at-offset + Slope * (FD - offset)

where

PR is protection ratio (dB)

FD is normalized frequency offset

PR is co-channel protection ratio

The segment used in the above formula is the one in which the upper

limit of the previous segment FD upper limit of the segment. For all

values of FD greater than the upper limit of the next to the last segment, the

last segment is used. For all values of FD less than the upper limit of the

first segment, the first segment is used.

7.5 CHANNELIZATION SCHEME* AND CHANNEL FAMILY**

The channelization scheme data contain the following information:

o Lowest Center Frequency: the center frequency of channel 1.

o Number of Channels: used only to determine whether the RARC

parameters are violated.

The channelization scheme key is set on records 2, 5-3 and 5-5 of the

scenario file. The scheme itself is defined in the channelization section of

the parameter file.

**The family key is set on record 5-3 and 5-5 of the scenario file. The

family itself is defined in the Channelization section of the Parameter file.

7-4
o Channel Bandwidth: also used only to determine whether the RARC

parameters are violated.

o Channel Separation:

 ;used to determine the center frequency of

all channels except channel 1.

o Channel Noise Bandwidth: used only to determine carrier to

noise ratio.

o Top Baseband Frequency and Peak-to-Peak Deviation: used to

determine Carson's Rule Bandwidth for protection ratio

calculations.

7-5
a u

•85 -•§ =•

' S f

CD £ ll

u

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i i

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a

a

a

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ORIGINAL PAGE IS

OF POOR QUAUTY

I I

S

MHMM

IT

2 2

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_

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t

7-5
Figure 7.1 gives a sample of a set of RARC parameters, a

channelization scheme and a set of channel families.

A violation of the RARC parameters would occur only if a channel in

the family overlaps one of the two guard bands. Channel one does not overlap

the guard band, but if the number of channels in the channelization is too

great, the upper channels will overlap the upper guard band and the user will

be warned. The L, M, and H on each channel family illustrate the nominal

frequency the user will get for each channel family by specifying the low,

median, or high nominal frequency option. This frequency is used for all gain

and attenuation calculations.

The interference categories between families are calculated using the

channel numbers only (the effect of the bandwidth is taken into account during

the calculation of protection ratio from the template).

7-7
VIII. AGGREGATE AND TOTAL INTERFERENCE AND MARGINS

For this discussion, "total" means the sum of up and down,

"aggregate" means sum over all interferers. All C/I and margin calculations

are performed in subroutine WRTAGU for up, WRTAGD for down, and WRTAGT for

total.

For the uppath C/I calculation, if power is specified directly or in

terms of EIRP, the feederlink transmitter (FIT) giving the weakest received

signal at the satellite yields the desired carrier signal. If power is

calculated from C/N or PFD, the FIT producing the strongest received signal

power is used. In all cases, the FIT from each service area giving the

strongest interfering signal is -used for the interference calculation. When

the user specifies rain attenuation, it is only used in uppath calculations

for the desired carrier signal calculations and user-specified rain fade

margin limits are never exceeded. All interferers are assummed to be in clear

weather.

8.1 AGGREGATE AND TOTAL INTERFERENCE

Defining (C/Oy/Q-H as the carrier-to-interference ratio in dB for

up or down in the ith interference category due to the jth interferer, then

the aggregate interference up or down in category i is:

dB*

S(C/Du/Dij 8-1

dB* = -10 log of inverted numerical power ratios.

8-1
The total aggregate C/I in category i is then defined as:

dB

U/D

Non co-channel intra-system interference is included in aggregate interference.

8.2 AGGREGATE AND TOTAL MARGINS

At the user's option, no interference from between systems of the

same administration, same satellite longitude and same channel family will be

added to the aggregate.

The aggregate margin for the i interference category for either

up or down is computed as:

MU/Di " (C/%Di - PRU/Di

where ^'^U/Di ^s tlle a99re9

ate carrier-to-interference ratio (up

or down) for the i interference category and PRnin- is the

aggregate protection ratio (up or down) in dB for the i

interference category.

The aggregate margin for up or down is computed as:

dB

MU/D

 = M 8 '

4

The total aggregate Margin in category i is computed as:

MTi = (C/I)T1 - PRTi 8-5

8-2
where PRy. is the total protection ratio in category i. Finally, the

total aggregate Margin is computed as

dB

My =y? M-ti

 8-6

1

8.3 GROUPING*

Two or more service areas may be combined into a group. Each group

of areas will be usually given a block of channels, to be divided however the

administrations of the grouped service areas see fit.

SOUPS uses the following rules for grouping:

o All interference categories calculated from channelizations are

ignored.

o The aggregate interference is calculated with the following

rules:

Co-channel interference

The sum of the highest co-channel interference power

levels from each group except its own.

Upper and lower adjacent channel interference

The sum of the highest adjacent channel interference

power levels from each group including those within its

own group (or system).

The grouping option is specified on Record 3 of the scenario file. Group

membership for each service are specified on record 5-1 of the same file.

8-3
Next upper and next lower adjacent channel interference

The sum of the highest second adjacent channel

interferences from each group including its own group

(and system).

8.4 NON-INTERFERENCE MATRIX

This matrix contains arbitrary flags indicating that specified

service areas cannot interfere with other specified service areas. This

matrix permits the selection of one service area from a set of related service

areas for the calculation of the interfering signal from, the set of areas. An

example of this would be only one service area of a multi-service area country

interfering into the service areas of another country.

8-4
SOUP 5

REFERENCES

1. Orbit/Spectrum Utilization Study, Volume IV, General Electric, Document

No. 71SD 4293, 31 December 1971.

2. ^pectrum/Orbit Utilization Program, User's Manual, by P. Sawitz and N.

Shusterman, 16 May 1974, ORI Technical Report 831.

3. Modification of the Spectrum-Orbit• Utilization Program - Final Report,

Joyce Kerr, Peter Sawitz, Fred Zusman, ORI Technical Report 1812, October,

1981.

4. jpectrum/Orbit Utilization Program, User a Programmer's Manual by Joseph

Davidson and Peter Sawitz, ORI Technical Report.

5. SOUPS Version 3 User's Manual, ORI Technical Report No. 2139

6. SJ)UP5 Programmer's Manual

7. CCIR Report 215-4, Volume XI, Table 1, p. 164

8. Ibid page 172, line 8

9. Ibid page 171, line 3

R-l
APPENDIX A

EQUIVALENT GAIN FOR EACH PARTIAL LINK

There are two antennas involved in each partial link, these have both

co-polar and cross-polar transmission and reception characteristics. In

addition atmospheric propagation effects, represented principally by co-polar

attenuation and cross-polar discrimination, influence the net received signal

power level.

The equivalent gain for one partial link can be represented by the

following approximation:

2 ? 6 = G-| cos B + G2 sin e

Gl =

62 =

GtpSrp *

.<

 GtpGrc

StcGrc +*t,*rc>

+ GtcGrp >2'

<

 + Gtc Srp X

k Gtp

 Grp

 X * Gtc

 Grc

X

where 6 , for linear polarization, is the relative alignment angle between the

transmitted and received polarization planes, this includes the effects of

antenna misalignment (both incidental and unavoidable), satellite yaw motion,

Faraday rotation (if any), etc. For circular polarization, e = 0° is

assumed to correspond to co-polar transmission and reception and e = 90° is

assumed to correspond to mutually cross-polarized transmission and reception.

A-l
attenuation (dB)

X = cross-polar discrimination (as a power ratio < 1)

=

,n0.1 (u - v log A) - .. •,.,. .

10

 v 3 ' for circular polarization

Subscripts:

t denotes transmission

r denotes reception

p denotes co-polar characteristic

c denotes cross-polar characteristic

In the expression for G-j, power summation of the terms is assumed

throughout. Near the mainbeam of the wanted transmission a voltage addition

of the first two terms may be more appropriate due to phase alignment whilst

away from this axis random effects would dictate power addition. However,

since the second term is insignificant near the mainbeam axis the assumption

of power addition does not compromise the approximation. Atmospheric

depolarization is a random effect, thus the last two terms are power summed.

In the expression for Gg, voltage addition of the first two terms

is assumed since, near the mainbeam axis, either term could be dominant and

phase alignment of these terms would dictate voltage addition. A power

addition of the first two terms is perhaps more appropriate away from the

mainbeam axis, but the validity of the assumed model is not unduly compromised

by the maintaining voltage addition in all regions. The above expressions, in

view of the arguments presented, are a reasonable compromise between accuracy

and simplicity.

A-2
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