MTR 01W0000024
MITRE TECHNICAL REPORT
Analysis of Potential MVDDS Interference to
DBS in the 12.212.7 GHz Band
April 2001
 2001 The MITRE Corporation.  All Rights Reserved.
MITRE
MTR 01W0000024
MITRE TECHNICAL REPORT
Analysis of Potential MVDDS Interference to
DBS in the 12.212.7 GHz Band
April 2001
Sponsor: Federal Communications Commission Project No.: 1201FCC2-01
Contract No.: FCC-2
This is the copyright work of The MITRE Corporation and was produced for the U.S. Government, the Federal
Communications Commission, and is subject to Federal Acquisition Regulation Clause 52.227-14, Rights in Data-General,
Alt. III (JUN 1987) and Alt. IV (JUN 1987).  No other use other than that granted to the U.S. Government, or to those
acting on behalf of the U.S. Government, under that Clause is authorized without the express written permission of The
MITRE Corporation.  For further information, please contact The MITRE Corporation, Contracts Office, 1820 Dolley
Madison Blvd., McLean, VA 22102, (703) 883-6000.
 2001 The MITRE Corporation.  All Rights Reserved.
The contents of this document reflect the views of The MITRE
Corporation and do not necessarily reflect the views of the Federal
Communications Commission.  The FCC does not make any warranty
or guarantee, expressed or implied, concerning the content or accuracy
of these views.
MITRE Project Approval:
D. James Chadwick
Director, Communications,
Navigation, and Surveillance
Division
iii
Abstract
The frequency band between 12.2 and 12.7 gigahertz (GHz) is allocated to Fixed and
Broadcasting-Satellite radio services on a co-primary basis.  In the United States, this band is
widely used for direct broadcast satellite (DBS) services.  Terrestrial radiocommunication
services are also permitted, provided that these do not interfere with the satellite services.  In
1999, Broadwave USA, a subsidiary of Northpoint Technologies, filed a petition with the
Federal Communications Commission (FCC) seeking an authorization to operate terrestrial
stations delivering Multichannel Video Distribution and Data Service (MVDDS) in the 12.2
12.7 GHz band.  Since that time, numerous concerns have been raised about the extent and
impact of potential interference of MVDDS transmissions on the existing DBS service.  This
report provides a thorough assessment of MVDDS interference into DBS receivers.  It is
based on a comprehensive analysis that included extensive laboratory and field
measurements.  The analysis also made use of modeling and simulation techniques to
validate published and measured performance results.  Special attention was given to the
degradation of system availability in the presence of rain losses.  The report also discusses
possible interference-mitigation approaches, recommends a process for licensing MVDDS
transmitters, and addresses key policy issues.
KEYWORDS: Spectrum sharing, MVDDS, DBS, interference, broadcast satellite, EchoStar,
DIRECTV, Dish TV, Northpoint, video quality.
v
Table of Contents
Section Page
1. Introduction 1-1
1.1  Background 1-1
1.2  MITREs Tasking 1-1
1.3  Approach 1-2
1.3.1  Equipment Measurements Task 1-2
1.3.2  Satellite Receiver Susceptibility Simulation 1-3
1.3.3  Propagation and Rain Modeling 1-3
1.3.4  Interference Predictions 1-3
1.4  Simplifying Assumptions 1-4
2. Interference Mechanisms 2-1
2.1  Direct-Coupled Interference 2-2
2.1.1  Assumptions 2-2
2.1.2  Notation 2-2
2.1.3  Algorithm 2-5
2.2  Rain Scatter Interference 2-8
3. Receiver Susceptibility 3-1
3.1  Theoretical Analysis and Predictions 3-1
3.1.1  Simulation Model Description 3-1
3.1.2  DBS Transmitter 3-2
3.1.3  Satellite Channel 3-2
3.1.4  DBS Receiver Model 3-3
3.1.5  MVDDS Interferer 3-4
3.1.6  Simulation Validation 3-4
3.1.7  Simulation Results 3-7
3.1.8  EchoStar Simulated Performance 3-7
3.1.9  DirectTV Simulated Performance 3-8
3.1.10  Simulation Summary 3-9
3.1.11  Theoretical Explanation 3-9
3.2  Testing of DBS Set-Top Boxes in the Presence of Northpoint MVDDS
Interference 3-12
3.2.1  Overview of Test Configuration for Receiver Degradation Measures 3-12
3.2.2  Standard for Signal Quality Measurement 3-12
3.2.3  DBS Signal Quality 6 in the Presence of Northpoint MVDDS Interference
Using 12 GHz RF Output with Simulated Adjacent Channels 3-13
3.3  Selection of Threshold Values from Theoretical and Measured Results 3-15
vi
3.3.1  Threshold for Noise Dominated Cases 3-15
3.3.2  Threshold Values for MVDDS Interference Dominated Cases 3-18
4. Antenna Patterns 4-1
4.1  MVDDS Antenna Patterns 4-1
4.1.1  Small Sectoral Horns 4-2
4.1.2  Large Sectoral Horns 4-4
4.2  DBS Antenna Patterns 4-6
4.2.1  DIRECTV 18-inch Reflector 4-6
4.2.2  DIRECTV 24 x 18 Reflector with Single Feed 4-8
4.2.3  DIRECTV 24 by 18-inch Reflector with Dual Feed 4-10
4.2.4  Fortel 4-13
4.2.5  Boresight Gain Summary 4-15
4.3  Polarization 4-16
4.3.1  The Transmitted Wave 4-16
4.3.2  Receive Antenna Response 4-17
4.3.3  Combined TX and RX 4-17
4.3.4  Polarization Model 4-19
5. Interference Assessment 5-1
5.1  Interference Predictions 5-1
5.1.1  Ranges of Parametric Values Used in the Simulations 5-2
5.1.2  Discussion of Results 5-6
5.2  Criteria for Sharing 5-11
5.2.1  Possible Sharing Criteria 5-11
5.2.2  Minimum C/I Criteria 5-12
5.2.3  Maximum Interference Level Criteria 5-16
6. Conclusions and Recommendations 6-1
6.1  Feasibility of MVDDS/DBS Bandsharing 6-1
6.2  Potential Interference-Mitigation Techniques 6-1
6.2.1  Selection of MVDDS Operational Parameters 6-2
6.2.2  Possible MVDDS System-Design Changes 6-3
6.2.3  Possible Corrective Measures at DBS Receiver Locations 6-4
6.3  Policy Issues and Recommendations 6-5
List of References RE-1
Appendix A. Testing of DBS Set-Top Boxes in the Presence of Northpoint MVDDS
Interference A-1
A.1  Overview of Test Configuration for Receiver Degradation Measures A-1
A.2  Details of the Test Configuration A-2
vii
A.2.1  Audiovisual (A/V) Signal Quality Determination A-3
A.3  Power Measurement for DBS, MVDDS, and Noise Signals A-4
A.3.1  Signal/Noise Power Measurements Using the Agilent 8564EC A-Spectrum
Analyzer A-4
A.4  Notes on Interference Testing A-6
A.4.1  Test Objectives A-6
A.4.2  DBS Equipment A-6
A.4.3  MVDDS Equipment A-7
A.4.4  Signal Quality Level 6 A-8
A.4.5  Elimination of Drive Power as Testing Variable A-9
A.4.6  Selection of Programming A-10
A.4.7  Determination of Transponder Transmitting a Particular Television
Channel A-11
A.5  DBS A/V Quality 6 in the Presence of Northpoint MVDDS Interference Using
70 MHz IF Output Translated to L Band with Simulated Adjacent Channels A-11
A.5.1  Test Configuration A-11
A.5.2  Test Results A-12
A.6  DBS A/V Quality 6 in the Presence of Northpoint MVDDS Interference Using
RF Output with Simulated Adjacent Channels A-14
A.6.1  Test Configuration A-14
A.6.2  Test Results A-16
A.7  DBS A/V Quality 6 in the Presence of Northpoint MVDDS Interference Using
RF Output with +7 MHz Offset and Simulated Adjacent Channels A-18
A.7.1  Test Configuration A-18
A.7.2  Test Results A-20
A.8  DBS A/V Quality 6 in the Presence of Northpoint MVDDS Interference
Using Open Air RF Transmission A-21
A.8.1  Test Configuration A-21
A.8.2  Test Results A-23
A.8.3  Notes on Open Air Testing A-24
A.9  Summary of Results A-25
Appendix B. Interference Predictions for Selected Scenarios B-1
Glossary GL-1
viii
List of Figures
Figure Page
2-1.  Rain Model Results for Representative DBS Locations 2-2
3-1.  Top Level Simulation Model 3-1
3-2.  DBS Transmitter Model 3-2
3-3.  Satellite Channel Model 3-3
3-4.  Satellite Filter Characteristics 3-3
3-5.  DBS Receiver Model 3-4
3-6.  EchoStar and DIRECTV Theoretical Performance 3-6
3-7.  EchoStar Simulation Results with Interference 3-8
3-8.  DIRECTV Simulation Results with Interference 3-8
3-9.  Probability Density Functions of Received QPSK Signal 3-9
3-10.  Probability Density Functions of Noise and Interference 3-11
3-11.  QPSK BER as Computed from Numerical Integration of Probability
Density Functions 3-11
3-12.  Functional Overview of DBS Video Test Configuration 3-12
3-13.  Carrier-to-Noise-Plus-Interference Required to Degrade DIRECTV to Signal
Quality 6 Vs. Interference-to-Noise Power Ratio; 12 GHz RF Output 3-14
3-14.  Carrier-to-Noise-Plus-Interference Required to Degrade Dish TV to Signal
Quality 6 Vs. Interference-to-Noise Power Ratio; 12 GHz RF Output 3-15
3-15.  Threshold Improvement 3-19
3-16.  Laboratory Data and Threshold Model for DIRECTV 3-20
3-17.  Laboratory Data and Threshold Model for Dish TV 3-21
ix
3-18.  Data and Threshold Model for 7 MHz Offset 3-22
4-1.  Small Sectoral Horn on Spherical Scanner 4-2
4-2.  Azimuthal Radiation Patterns of Small Sectoral Horns 4-3
4-3.  Elevation Radiation Pattern of Northpoint Small Sectoral Horn 4-3
4-4.  Large Sectoral Horn on Spherical Scanner 4-4
4-5.  Azimuthal Radiation Patterns of Large Sectoral Horns 4-5
4-6.  Elevation Radiation Pattern of Large Northpoint Sectoral Horn 4-5
4-7.  DIRECTV 18-inch Reflector on Spherical Scanner 4-6
4-8.  Azimuthal Radiation Pattern of DIRECTV 18-inch Reflector 4-7
4-9.  Elevation Radiation Pattern of DIRECTV 18-inch Reflector 4-7
4-10.  RHCP Radiation Pattern of DIRECTV 18-inch Reflector 4-8
4-11.  Azimuthal Radiation Pattern of DIRECTV 24-by-18-inch Reflector with
Single Feed 4-9
4-12.  Elevation Radiation Pattern of DIRECTV 24-by-18-inch Reflector with
Single Feed 4-9
4-13.  RHCP Radiation Pattern of DIRECTV 24 by 18-inch Reflector with Single
Feed 4-10
4-14.  DIRECTV 24-by-18-inch Reflector with Dual Feed on Spherical Scanner 4-11
4-15.  Azimuth Radiation Pattern of DIRECTV 24-by-18-inch Reflector with
Dual Feed 4-11
4-16.  Elevation Radiation Pattern of DIRECTV 24-by-18-inch Reflector with
Dual Feed 4-12
4-17.  RHCP Radiation Pattern of DIRECTV 24-by-18-inch Reflector with
Dual Feed 4-13
4-18.  Azimuth Radiation Pattern of Fortel Flat Panel Antenna 4-14
x
4-19.  Elevation Radiation Pattern of Fortel Flat Panel Antenna 4-14
4-20.  RHCP Radiation Pattern of Fortel Flat Panel Antenna 4-15
4-21.  True Gain Product 4-20
4-22.  MITRE Model for Gain Product 4-21
4-23.  Dominant Mode Model for Gain Product 4-22
5-1.  Interference Impact Predictions for Benchmark Case 5-3
5-2.  Percentage of Increase of Unavailability for DBS System 5-13
5-3.  Increase in Time of Unavailability for DBS System 5-14
5-4.  Total Percentage of Time of Unavailability in an Average Year for
DBS System 5-15
5-5.  Total Unavailability for Washington, DC 5-18
5-6.  Total Unavailability in Hours for Washington, DC 5-20
5-7.  Increase in Unavailability 5-21
5-8.  Relative Increase in Unavailability 5-22
5-9.  Total Unavailability, Fargo 5-23
5-10.  Unavailability in Hours, Fargo 5-24
5-11.  Unavailability Increase, Fargo 5-25
5-12.  Relative Increase in Unavailability, Fargo 5-26
5-13.  Unavailability (%) for Miami, FL 5-27
5-14.  Unavailability (Hours) for Miami, FL 5-28
5-15.  Increase in Unavailability (Hours) for Miami, FL 5-29
5-16.  Relative Increase in Unavailability (%) for Miami, FL 5-30
5-17.  Total Unavailability (%) for QEF in Washington, DC 5-31
xi
5-18.  Total Unavailability (Hours) for QEF in Washington, DC 5-32
5-19.  Unavailability Increase (Hours) for QEF in Washington, DC 5-33
5-20.  Relative Increase in Unavailability (%) for QEF in Washington, DC 5-34
A-1.  Functional Overview of DBS Video Test Configuration A-1
A-2.  Details of the Test Configuration for DBS Video Testing A-2
A-3.  Notional Depiction of DBS Effective Bandwidth A-6
A-4.  Set-Top Boxes Used in Receiver Testing A-7
A-5.  Northpoint MVDDS Single Channel Transmitter A-8
A-6.  Comparison of 2 Different Drive Powers for DIRECTV A-10
A-7.  Comparison of 2 Different Drive Powers for Dish TV A-10
A-8.  Configuration for Northpoint Transmitter IF Output with Adjacent Channels A-11
A-9.  Single Channel MVDDS IF Interference Plus Adjacent Ahannels Generated
from Arbitrary Waveform Synthesizers A-12
A-10.  Carrier-to-Noise-Plus-Interference Required to Degrade DIRECTV to A/V
Quality 6 Vs. Noise-to-Interference Power Ratio; 70 MHz IF A-13
A-11.  Carrier-to-Noise-Plus-Interference Required to Degrade Dish TV to A/A
Quality 6 Vs. Noise-to-Interference Power Ratio; 70 MHz IF A-14
A-12.  Interference Test Configuration Using Northpoint Transmitter with LNB A-15
A-13.  Single Channel MVDDS Downcoverted RF Interference Alus Adjacent
Channels Generated from Arbitrary Waveform Synthesizers A-16
A-14.  Carrier-to-Noise-Plus-Interference Required to Degrade DIRECTV to A/V
Quality 6 Vs. Noise-to-Interference Power Ratio; 12 GHz RF Output A-17
A-15.  Carrier-to-Noise-Plus-Interference Required to Degrade Dish TV to A/A
Quality 6 Vs. Noise-to-Interference Power Ratio; 12 GHz RF Output A-18
A-16.  Interference Test Configuration Using Northpoint Transmitter with A7 MHz
Offset and LNB Downconverter A-19
xii
A-17.  Single Channel MVDDS (with 7 MHz Offset With Aespect to DBS
Channelization) Downcoverted RF Interference Plus One Adjacent
Channel Generated from Arbitrary Waveform Synthesizer A-20
A-18.  Carrier-to-Noise-Plus-Interference Required to Degrade DIRECTV to A/V
Quality 6 Vs. Noise-to-Interference Power Ratio; Northpoint MVDDS
12 GHz RF Output, + 7 MHz Offset from DBS Channelization A-21
A-19.  Configuration for Open Range Testing of Northpoint AVDDS Interference to
DBS Systems A-22
A-20.  Single Channel MVDDS Open Range Transmission Aoupled into Spillover
Region of a DBS Receive Dish A-23
A-21.  Carrier-to-Noise-Plus-Interference Required to Degrade DIRECTV to A/V
Quality 6 Vs. Noise-to-Interference Power Ratio; Northpoint MVDDS
12 GHz RF Output, Open Range A-24
xiii
List of Tables
Table Page
3-1.  Transmitter Model Parameters 3-2
3-2.  Calculation of (C/N) to (Eb/N
0
) Conversion Factors 3-5
3-3.  Simulation Results Summary 3-9
3-4.  DBS Signal Quality Criteria 3-13
3-5.  Summary of Eb/No for QEF Performance (dB) 3-17
3-6.  Summary of C/N Values (dB) 3-18
3-7.  System Model Threshold Improvement Factors 3-23
4-1.  Boresight Gain Summary 4-16
5-1.  EIRP-to-Threshold Ratios (dBW) and Unavailabilities for VQ6 5-5
5-2.  Example of Minimum [CI
MV
]
0
 to Satisfy the Requirement V? 10 (%) 5-16
5-3.  Satellite Summary 5-19
A-1.  DBS A/V Quality Criteria A-3
A-2.  Spectrum Analyzer Settings A-4
A-3.  Power Occupied Bandwidth of DBS Signal A-4
xv
Executive Summary
The frequency band between 12.2 and 12.7 gigahertz (GHz) is allocated to the Fixed and
Broadcasting-Satellite radio services on a co-primary basis.  International
Telecommunications Union (ITU) Footnote S5.490 permits the operation of stations that
provide terrestrial radiocommunication services in the same band, subject to the restriction
that they shall not cause harmful interference to the space services operating in conformity
with the broadcasting satellite Plan for Region 2 contained in Appendix S30.  CFR 47, Part
100 codifies U.S. regulations for Direct Broadcast Satellite (DBS) service in this band.
In 1999, Broadwave USA, a subsidiary of Northpoint Technologies, Inc., filed a petition
with the Federal Communications Commission (FCC) seeking an authorization to operate
terrestrial stations delivering Multichannel Video Distribution and Data Service (MVDDS) in
the 12.212.7 GHz band.  Subsequently, two other companies, PDC Broadband Corporation
and Satellite Receivers, Ltd. filed similar applications with the FCC.
The FCC issued a Notice of Proposed Rulemaking on 24 November 1998, and a First
Report and Order (R&O) and a Further Notice of Proposed Rulemaking (NPRM) as ET
Docket 98-206 on 8 December 2000.  These documents address the issues associated with
permitting MVDDS in the band, and conclude that sharing the band between MVDDS and
DBS systems is possible, subject to certain precautions that must be taken to prevent
interference to DBS systems.
The FCCs Fiscal Year (FY) 2001 budget authorization contains a requirement that the
FCC select an independent engineering firm to perform an analysis to determine whether
these two services can share the band without harmful interference to DBS systems.  The
FCC selected The MITRE Corporation to perform this work.  The 19 January 2001
Statement of Work for the project says that The objective of the tasks is to perform a
technical demonstration or analysis of any terrestrial service technology proposed by any
entity that has filed an application to provide terrestrial service in the direct broadcast
satellite frequency band to determine whether the terrestrial service technology proposed to
be provided by that entity will cause harmful interference to any direct broadcast satellite
service.
MITREs effort was divided into tasks in the following areas:
 Equipment measurements
 Satellite receiver simulation
 Propagation and rain-attenuation modeling
 Interference predictions
xvi
All measurements for the project were conducted at MITREs laboratories in Bedford,
Massachusetts.  MITRE measured the radiation patterns of three DBS antennas and two
MVDDS antennas in its anechoic chamber, which has been extensively used to make
measurements of critical defense systems for several years.  DBS receiver susceptibility to
MVDDS interference was measured in the laboratory by connecting an MVDDS transmitter
to a DBS receiver through an attenuator, and varying the MVDDS signal level to generate a
set of susceptibility curves.  The DBS receiver was operating with a live signal from the
satellite at the time of these measurements.  Limited field measurements of the MVDDS
signal level at the terminals of the DBS antenna were also made for a variety of DBS antenna
orientations.  Appendix A contains a detailed description of measurement procedures.
MITREs Fort Monmouth, New Jersey laboratory used the Signal Processing
Workstation (SPW) software package to model the DBS/MVDDS interference
environment in order to provide an independent verification of the laboratory measurements.
Runs were made for the combinations of code rate, interleaver length and Reed-Solomon
error correction that are in use by DBS vendors.  The simulations produced results that were
consistent with those derived from the laboratory and field measurements.  Details of the
simulation can be found in Section 3.1.
The primary propagation mechanism of interest in this analysis is the attenuation of DBS
signals by rain, which is the most significant variable in the computation of downlink
availability.  The amount of attenuation is a function of rain rate, which varies with
geographic location.  Section 2 provides a discussion of the rain model used in this analysis.
To quantify the effect that MVDDS systems would have on DBS reception, a model was
developed that incorporates the measured and simulated susceptibility data, the rain
attenuation statistics, and the equipment parameters of the two systems.  This model was run
for ten locations throughout the contiguous United States to assess the impact of MVDDS
operations on DBS reception.  The locations were selected to cover the full range of climatic
regions and DBS elevation angles.  The model produced plots showing areas where the
interference-impact criterion (change in unavailability) was exceeded.  From these plots, it
was possible to determine the feasibility of MVDDS deployment in the band.
Conclusions
The analysis and testing performed by MITRE and described elsewhere in this report
have demonstrated that:
 MVDDS sharing of the 12.212.7 GHz band currently reserved for DBS poses a
significant interference threat to DBS operation in many realistic operational
situations.
xvii
 However, a wide variety of mitigation techniques exists that, if properly applied
under appropriate circumstances, can greatly reduce, or eliminate, the geographical
extent of the regions of potential MVDDS interference impact upon DBS.
 MVDDS/DBS bandsharing appears feasible if and only if suitable mitigation
measures are applied.  Different combinations of measures are likely to prove best
for different locales and situations.
The question remains:  do the potential costs of applying the necessary mitigatory
measures, together with the impact of the residual MVDDS-to-DBS interference that might
remain after applying such measures, outweigh the benefits that would accrue from allowing
MVDDS to coexist with DBS in this band?  To facilitate the FCCs decision, we have
assessed the probable effectiveness of available mitigation techniques in reducing the
potential impact and geographical extent of MVDDS interference upon DBS operations.
Techniques for preventing or reducing MVDDS interference in DBS receivers fall into
three general categories:
 Selection of MVDDS operational parameters
 Possible MVDDS system-design changes
 Corrective measures at DBS receiver locations
Mitigatory techniques in each of these three categories are discussed in detail in
Section 6.2.  The most important operational parameters that can be adjusted to control
interference in existing MVDDS system designs are transmitter power, frequency offset,
tower height, elevation tilt, and azimuthal orientation.
 Keeping MVDDS transmitter power as low as possible without sacrificing coverage
requirements is the most basic and obvious means for controlling interference to
DBS.
 The use of a 7-MHz frequency offset between the MVDDS and DBS carriers has been
shown through MITREs testing to reduce effective interference levels by 1.7 dB, and
noticeably shrinks the areas in which DBS receivers are potentially affected by
MVDDS interference.
 Increasing the MVDDS transmitting antenna height reduces the sizes of the areas
susceptible to a given level of interference.  However, the simulations of pages  B-11
through B-15 indicate that substantial benefits may not accrue unless the tower height
is at least 100, or perhaps even 200, meters above the level of the DBS receiving
antennas in the surrounding area.
 Adjusting the elevation tilt of the MVDDS transmitting antenna may not be
particularly effective.  Tilting the antenna up 5 reduces the interference-impact area
xviii
but shrinks the MVDDS coverage area in roughly the same proportion.  This
presumably means that more MVDDS towers (creating additional interference-impact
areas) would be needed to cover a given geographical region than if the antennas had
not been tilted.
 Pointing the MVDDS transmitting antennas away from the satellites, rather than
toward them as generally envisioned, could have beneficial effects in many
situations.  These are indicated by the simulation results of pages B-21 and B-23, and
by the outputs of several other simulations in which easterly and northerly MVDDS
transmitter boresight azimuths were used.  When the satellites are generally to the
south and their elevation angle is reasonably high, as in Denver, dramatic
improvements in interference protection appear possible when the MVDDS
transmitting antenna points north.  When satellite elevation angles are somewhat
lower (as in Seattle) the geometry is somewhat less favorable, but north-pointing
seems to yield significant benefits in all locales where it has been simulated.  Further
testing to validate this concept is recommended.
Potential MVDDS design changes that might reduce the interference impact on DBS
downlinks include real-time power control, multiple narrow transmitting-antenna beams, the
use of circular polarization, and increasing the size of MVDDS receiving antennas.
 Real-time power control, which would reduce MVDDS transmitter power as
necessary to protect DBS downlinks from degradation during rain, has sometimes
been proposed as a technique for controlling MVDDS-to-DBS interference.
 The use of multiple MVDDS transmitting-antenna beams, each having a much
narrower azimuthal beamwidth than the existing sectoral horns, might provide much
better flexibility than the present antenna design in directing the interference-impact
regions away from areas containing DBS subscribers.
 Circularly polarized MVDDS transmitting antennas, if they used the same system of
alternate senses for adjacent channels that is employed by DBS, might pose a
considerably smaller interference threat than the currently planned exclusive use of
horizontal polarization, for reasons explained in Section 6.2.2.
 Larger MVDDS receiving antennas, recently suggested by Pegasus, would increase
their achievable gains and hence the G/T ratios of MVDDS receivers.  This in turn
would allow an MVDDS system to cover an identical service area with a smaller
output power and hence with smaller resultant interference-impact regions.
Corrective measures that can be applied at DBS receiver installations include relocation
and retrofitting of existing DBS antennas, the use of alternative antenna designs, and the
replacement of older DBS set-top boxes.
xix
 Relocation of DBS receiving antennas to put nearby buildings between them and
nearby MVDDS interferers, while still leaving desired satellites in view, is a well-
known corrective measure that would undoubtedly be effective in many situations.
 The use of absorptive or reflective clip-on shielding for existing DBS antennas, to
block any direct lines of sight that might exist between their LNBs (antenna feeds)
and potentially interfering MVDDS transmitting antennas, is a technique that worked
quite well during MITREs open-air testing.
 DBS receiving-antenna replacement is a relatively expensive but potentially effective
mitigatory technique.  For example, the simulation of page B-30 has shown the
potential benefits of using single-feed 24x18 antennas instead of the more
commonly used 18 dishes.
 Replacement of older DBS set-top boxes may prove to be a useful mitigation
technique if more recent models are more resistant to in-band interference.
Recommendations
If licensing of new MVDDS services is to be successful, while preventing significant
interference to DBS services, a number of policy issues need to be considered and resolved.
These resolutions naturally lead to a licensing and deployment process for new MVDDS
services.  In Section 6.3, MITRE recommends a procedure for coordinating MVDDS
applications to minimize interference to DBS systems.
A number of additional policy issues should also be considered.  These issues and
questions are discussed below, along with MITREs recommendation to the FCC.
 Should future DBS customers be protected and for how long?
Recommendation:  Yes, future DBS customers should be protected for as long as the
MVDDS transmitter operates.  The MVDDS service provider would need to measure
C/I values and provide mitigation solutions to these new customers in the
interference-mitigation region.
 Test results and analyses have been based on known MVDDS waveforms.  Should
new waveforms be allowed?
Recommendation:  New waveforms create an unknown vulnerability. MITRE
recommends that these not be licensed without further study.
 Should the evaluation of sharing consider any DBS satellite in the geostationary arc,
or should only existing U.S. satellites be considered?  What about new U.S.
satellites?
Recommendation:  DBS receivers operating with new and different satellites could be
at risk in unforeseen ways.  MITRE recommends that any satellites not addressed in
the current report be studied further.
xx
 If changes and improvements are made to any DBS system waveform, how should
this impact policy?
Recommendation:  Results in this report are based on specific systems with known
parameters.  MITRE recommends that any new DBS waveforms be subject to further
study.
 Should DBS satellites with weak coverage be protected?  If so, how weak can these
be and at what level should they be protected?  (See examples in Section 5.2.3 and
elsewhere.)  What is the maximum baseline and degraded unavailability that should
be allowed?
Recommendation:  Only DBS satellites with baseline unavailabilities of 100
hours/year or less, when operating without MVDDS interference into a DBS antenna
with G/T of 11.2 dB/K, should be protected.  DBS receivers operating with satellites
that do not meet this criterion should not be protected from MVDDS interference
when operating with such satellites.
 How should the advent of new DBS antennas affect the policy for MVDDS
licensing?
Recommendation:  DBS antennas with G/T performance below 11.2 dB/K could
seriously degrade DBS availability in rain.  If the MVDDS service provider opts to
mitigate MVDDS interference with the use of a different antenna, the replacement
antenna should have a G/T at least as great as that of the original antenna.
 Should other causes of unavailability (besides rain and MVDDS interference) be
included in the total budget?
Recommendation:  Other sources of outage should be considered, if they are
significant and if their effect is known and documented.  Sun-transit outages are an
example.
 MVDDS antenna backlobes can interfere with a DBS antenna main beam.  This
would typically occur close to the MVDDS transmitter, generally north of the
antenna.  These regions are typically very small.  Should very small regions of
interference be exempted because of their small size?
Recommendation:  These small regions should not be exempted.  All regions of the
interference-mitigation region should be considered, regardless of size.
 Should MVDDS mitigation be based solely on customer complaints?
Recommendation:  MITRE believes that DBS customers may not know what is
causing a particular outage, or the reason for its duration.  Consequently, mitigation
should not await DBS customer complaints.  MITRE believes that mitigation should
be done proactively, regardless of the presence or absence of such complaints.
 How much time should the MVDDS service provider be allowed in order to
implement mitigation to the DBS receivers?
xxi
Recommendation: To the maximum extent possible, mitigation should be
accomplished prior to a license being granted for MVDDS operation.
MITRE believes that with implementation of the licensing process described in
Section 6.3 and the other policy recommendations outlined above, spectrum sharing between
DBS and MVDDS services in the 12.212.7 GHz band is feasible.  However, MITRE
recognizes that it is the FCC that must ultimately resolve the various policy issues and the
approach to licensing new MVDDS services.
1-1
Section 1
Introduction
1.1  Background
The frequency band between 12.2 and 12.7 gigahertz (GHz) is allocated to the Fixed and
Broadcasting-Satellite radio services on a co-primary basis.  The International Rules for
assigning frequencies in this band are contained in the International Telecommunications
Union (ITU) Radio Regulations, Volume 2, Appendix S30.  In Region 2, which includes the
United States (U.S.), ITU Footnote S5.490 permits the operation of stations that provide
terrestrial radiocommunication services, subject to the restriction that they shall not cause
harmful interference to the space services operating in conformity with the broadcasting
satellite Plan for Region 2 contained in Appendix S30.  CFR 47, Part 100 codifies U.S.
regulations for Direct Broadcast Satellite (DBS).
In 1999, Broadwave USA, a subsidiary of Northpoint Technologies, Inc., filed a petition
with the Federal Communications Commission (FCC) seeking an authorization to operate
terrestrial stations delivering Multichannel Video Distribution and Data Service (MVDDS) in
the 12.2 to 12.7 GHz band.  Subsequently, two other companies, PDC Broadband
Corporation and Satellite Receivers, Ltd. filed applications with the FCC to provide MVDDS
in this band.
The FCC issued a Notice of Proposed Rulemaking on November 24, 1998, and a First
Report and Order (R&O) and a Further Notice of Proposed Rulemaking (NPRM) as ET
Docket 98-206 on December 8, 2000.  These documents address the issues associated with
permitting MVDDS in the band, and conclude that sharing the band between MVDDS and
DBS systems is possible, subject to certain precautions that must be taken to prevent
interference to DBS systems.
The FCCs Fiscal Year (FY) 2001 budget authorization contains a requirement that the
FCC select an independent engineering firm to perform an analysis to determine whether
these two services can share the band without any interference to DBS systems.  The FCC
selected The MITRE Corporation to perform this work.
1.2  MITREs Tasking
The FCC provided MITRE with the following task description as part of the Statement of
Work (FCC, 19 January 2001) for the project:
Caveats.  The Contractor shall carry out all the tasks as an independent technical
consultant.  In particular, the Contractor shall ensure that the personnel performing
1-2
the tasks do not have any financial or other material interests in any party to the
technical demonstration.
Objective.  The objective of the tasks is to perform a technical demonstration or
analysis of any terrestrial service technology proposed by any entity that has filed an
application to provide terrestrial service in the direct broadcast satellite frequency
band to determine whether the terrestrial service technology proposed to be provided
by that entity will cause harmful interference to any direct broadcast satellite service.
Specific Tasks.  The contractor shall perform the following tasks, as a minimum:
1. Contact the appropriate parties in each of the relevant companies to obtain any
technical information, equipment, and/or specifications needed for the
demonstration or analysis.
2. Develop a work plan to perform all demonstrations or analyses needed to
comply with the statutory requirements.
3. Prepare progress reports on the status of the demonstration or analysis.
4. Prepare a Final Report that fully describes the demonstration or analysis and
provides conclusions.  The Final Report must include relevant supporting
information regarding the data, equipment, specifications and analyses used,
discuss how demonstrations or analyses were performed, and provide the
basis upon which conclusions were reached.  The Final Report will be made
available by the FCC for public comment.
1.3  Approach
MITRE assigned a Program Manager to the project, who was responsible for all aspects
of the work.  Four Technical Leads were assigned to manage tasks in the following areas:
 Equipment Measurements (antennas, MVDDS transmitter, DBS receivers, field
measurements)
 Satellite Receiver Simulation (with a simulated MVDDS signal as an interference
source)
 Propagation and Rain Attenuation Modeling
 Interference Predictions
1.3.1  Equipment Measurements Task
All measurements for the project were conducted at MITREs laboratories located in
Bedford, MA.  MITRE measured the gain, polarization and phase of three DBS antenna and
1-3
one MVDDS antenna in its anechoic chamber, which has been extensively used to make
measurements of critical defense systems for several years.  DBS receiver susceptibility to
MVDDS interference was measured in the laboratory by connecting an MVDDS transmitter
to a DBS receiver through an attenuator, and varying the MVDDS signal level to generate a
set of susceptibility curves.  The DBS receiver was operating with a live signal from the
satellite at the time of these measurements.  Data was taken under two MVDDS frequency
conditions:  (1) MVDDS transmitter operating at the same frequency as the DBS signal; and
(2) the MVDDS transmitter off-tuned by 7 megahertz (MHz).  Limited field measurements
of the MVDDS signal level at the terminals of the DBS antenna were also made for a variety
of DBS antenna orientations.  The laboratory and field measurements yielded consistent
results.  Details of the measurement setups, techniques and results can be found in Sections
3.23.3 (DBS receiver) and Section 4 (antennas).
1.3.2  Satellite Receiver Susceptibility Simulation
MITREs Fort Monmouth, NJ laboratory has a capability to simulate virtually any
electronic architecture using the Signal Processing Workstation (SPW) software package.
SPW was configured to model the DBS/MVDDS interference environment in order to
provide an independent verification of the laboratory measurements.  Runs were made for all
combinations of code rate, interleaver length and Reed-Solomon error correction that are in
use by DBS vendors.  The simulations produced results that were consistent with those
derived from the laboratory and field measurements.  Details of the simulation can be found
in Section 3.1.
1.3.3  Propagation and Rain Modeling
The primary propagation mechanism of interest in this analysis is the attenuation of DBS
signals by rain.  This is because it is the most significant variable in the computation of link
availability.  DBS signals become more susceptible to MVDDS interference when it is
raining because the desired signal is attenuated.  The amount of attenuation is a function of
rain rate, which varies with geographic location.  Section 2 provides a discussion of the
selection of a rain model for this analysis.
1.3.4  Interference Predictions
In order to quantify the effect that MVDDS systems would have on DBS reception, a
model was developed that incorporated the measure susceptibility data, the rain attenuation
statistics and the equipment parameters of the two systems.  This model was run for several
locations throughout the 50 States to assess the impact of MVDDS operations on DBS
reception.  The locations were selected to cover the full range of DBS antenna elevation
angles, DBS satellite orbit longitudes and rain regions.  The model produced plots showing
areas where the DBS interference criterion (change in availability) was exceeded.  From
1-4
these plots, it was possible to determine the feasibility of MVDDS deployment in the band.
Section 5.1 describes the model and interprets the plots, which are contained in Appendix B.
1.4  Simplifying Assumptions
The following parameters or conditions were not considered in MITREs analysis.  They
were either determined to have a negligible effect on the results, or they were noted as being
specific to a site and thus not analytically tractable for purposes of this study.
Items with negligible effects include:
 DBS sun transit effects
 Rain fading effects on the DBS uplink
 DBS transponder intermodulation effects
 DBS outages caused by hardware or software failures
 Interference from systems other than MVDDS and DBS
 Interference from multiple MVDDS systems at the same location (since a given DBS
antenna will seldom be susceptible, while pointed in a given direction, to two
different MVDDS antennas serving different areas)
Site-specific and analytically intractable items include:
 Rain effects on the MVDDS signal
 Foliage attenuation of MVDDS and DBS signals
 Shadowing of MVDDS and DBS signals by buildings and terrain
 Scattering and reflection of the MVDDS signal from buildings and terrain
 Manufacturing, installation and maintenance tolerances affecting DBS and MVDDS
antenna performance (except that a 0.5 decibel [dB] DBS antenna pointing error was
considered in link calculations)
 Snow, ice, and wind effects on antenna performance
 DBS power reduction resulting from spacecraft system aging
2-1
Section 2
Interference Mechanisms
The primary propagation characteristic of interest for the interference analysis is the
attenuation of satellite signals due to rain.  The reason the rain attenuation is important is
because it is the leading variable factor in the computation of link availability.  Also, the
satellite signals become more susceptible to MVDDS interference during rain because of the
reduced signal level caused by the rain fade.
Several possible models could be used to represent the attenuation effects of rain.  Of
these, the model described in ITU-R P.618-6 was used.  This model was chosen because an
ITU-R model has been widely used by the proponents in evaluating possible MVDDS
interference (DIRECTV, 2000; Combs, 2001).  The FCC in its First Report and Order and
Further Notice of Proposed Rule Making also used the ITU-R model (FCC, 2001).  To
achieve the best possible accuracy, the latest version of the model was used, version 6.
For use in this study, the ITU-R P.618-6 rain attenuation model was implemented in
MATLAB and integrated with the other analysis algorithms.  MATLAB routines were
created for both  forward and reverse calculations.  In effect, the forward method
facilitates calculating the rain attenuation for a given unavailability, while the reverse
method calculates the outage probability for a given rain attenuation.  The forward
calculation is useful for computing the link unavailability for a given link budget, while the
reverse calculation is useful for generating C/I contours for specific outage probabilities.
The reverse calculation is based on a simple sequential search of probabilities, looking for
the desired rain attenuation.
Figure 2-1 depicts the rain model results for representative DBS locations used in FCC
00-418 (ITU, 1999b).  In this figure, rain attenuation is plotted as a function of the
probability that the given attenuation is exceeded.
The method used within the rain models uses the rainfall for an average year.  It should
be noted that there is often large seasonal and year-to-year variability in the actual rainfall
experienced.  Further, local rain rate characteristics, if available, may provide for more
accurate rain attenuation estimates.  Hence, the use of these models provides only a reference
for evaluation.
Of lesser importance than the rain attenuation, but also a factor that needs to be
considered, is the attenuation of satellite signals due to atmospheric gases.  The atmospheric
attenuation is approximated by all the proponents in this proceeding as 0.2 dB for DBS
signals in the DBS frequency band (DIRECTV, 2000; Combs, 2001), and is computed from
(ITU, 1999a).  Although there is some variability of the atmospheric attenuation with earth
station elevation angle, this is a reasonable approximation.
2-2
0
5
10
15
20
25
30
35
0.001 0.01 0.1 1
Probability (%)
Rain Attenuation (dB)
Denver
Washington
Seattle
Miami
Figure 2-1.  Rain Model Results for Representative DBS Locations
2.1  Direct-Coupled Interference
The following procedures provide estimates of the contours of constant DBS-downlink
unavailability and related parameters resulting from MVDDS interference.
2.1.1  Assumptions
 Link outages due to DBS uplink rain fading are not considered.
 The calculated C/I is performed by not fading the MVDDS signal with rain.
 The rain loss (attenuation) exceeded 0.01% of time in an average year, A
0.01
, is
modeled according to the ITU-R Recommendation P. 618-6.
2.1.2  Notation
A (dB) rain loss
A
eRm
 (dB) effective rain margin in the presence of MVDDS interference
A
Rm
 (dB) rain margin
2-3
A
0.01
 (dB) rain loss (attenuation) exceeded 0.01% of time in an average year
B
D
 (deg) latitude of the DBS rx
CI
B
 (dB) C/I for DBS adjacent satellite interference
CI
M
 (dB) rainy-sky C/I for MVDDS interference
CI
MV
 (dB) value of CI
M
 when I
M
 effects a change in the rain margin from A
Rm
 to
A
eRm
CN
A
 (dB) C/N for DBS rx when rain loss is equal to A
CN
AeRm
 (dB) value of CN
A
 when A = A
eRm
CN
ARm
 (dB) value of CN
A
 when A = A
Rm
CN
C
 (dB) C/N for cross-polarization interference
CN
0
 (dB) C/N for DBS rx when A = 0 (i.e., clear-sky)
CNI
sys
 (dB) C/N plus I of the system
CNI
Th
 (dB) required C/N plus I operating threshold of DBS rx
CN
U
 (dB) C/N for DBS feeder uplink
E
d
 = 0.9 dissipation efficiency of the antenna
e
d
 (deg) elevation angle of the DBS rx antenna towards the satellite
E
i
 = 0.778 illumination efficiency of the antenna
EIRP
sat
 (dBW) effective isotropically radiated power (EIRP) of satellite towards
DBS rx
f
MHz
 (MHz) DBS operating frequency
F
t
 = 8 (dB) noise figure of tuner with cable attached
G
Hr
 (?
i
, ?
i
) (dB) gain of DBS rx antenna horizontal polarization in direction (?
i
, ?
i
)
towards the MVDDS tx
G
Ht
 (?
t
, ?
t
) (dB) gain of MVDDS tx antenna horizontal polarization in direction
(?
t
, ?
t
) towards the DBS rx
G
l
 = 50 (dB) gain of LNB
G
Lr
 (?
r
, ?
r
) (dB) gain of DBS rx antenna left hand circular polarization in direction
(?
r
, ?
r
) towards the satellite
G
Vr
 (?
i
, ?
i
) (dB) gain of DBS rx antenna vertical polarization in direction (?
i
, ?
i
)
towards the MVDDS tx
2-4
G
Vt
 (?
t
, ?
t
) (dB) gain of MVDDS tx antenna vertical polarization in direction (?
t
, ?
t
)
towards the DBS rx
I
M
 (dBW) DBS received power of MVDDS interference
k (dB) Boltzman constant
L
a
 (dB) DBS rx  satellite path atmospheric absorption
L
Mfree
 (dB) DBS rx  MVDDS tx path loss (free-space path loss)
L
pt
 (dB) DBS rx antenna  satellite pointing loss
L
Sfree
 (dB) DBS rx  satellite path loss (free-space path loss)
mf
Th
 (dB) MVDDS interference calibration factor related to DBS rx threshold
P
M
 (dBW) radiated power of MVDDS tx
p
Rm
 (%) percentage time of DBS outage due to rain (associated with rain
margin A
Rm
)
p
total
 (%) total percentage time of DBS downlink outage (due to rain plus
MVDDS interference)
Q (kilometer [km]) distance between DBS rx and DBS satellite
R
M
 (km) distance between MVDDS tx and the geographical grid point under
consideration
SAV (%) system availability
T
A
 (K) system temperature in presence of rain loss A
T
a
 = 290 (K) temperature of atmosphere
T
b
 = 50 (K) temperature of the background (antenna sidelobes)
T
p
 = 300 (K) physical temperature of the antenna
T
r
 = 260 (K) temperature of the rain
T
s
 = 4 (K) noise temperature of sky the antenna is looking at
T
0
 (K) clear-sky system temperature
T
1
 = 80 K noise temperature of LNB
U
0
 (min) time of DBS service outage per year in the absence of MVDDS
interference
U
total
 (min) total time of DBS service outage per year in the presence of MVDDS
2-5
?U (min) time of DBS service outage increase per year due to the presence of
MVDDS
V (%) percentage increase of DBS downlink outage time due to MVDDS
interference
W
D
 (Hz) bandwidth of DBS
W
M
 (Hz) bandwidth of MVDDS
W
n
 (Hz) DBS noise bandwidth
X7 (dB) MVDDS interference 7 MHz offset calibration factor
2.1.3  Algorithm
The rationale of adopting antenna gains in specific polarization senses will be discussed
in Section 4.5.  The sequence of computation is described in the following:
Step 1:  Calculate the DBS satellite to DBS rx (earth station) free space path loss
L
Sfree
 = 32.44 + 20 log (f
MHz
) + 20 log Q
Step 2:  Calculate the system temperature T
A
 in rain loss of A
(1) Effective noise temperature of the LNB
T
eff
 = T
1
 + T
a
 
1010
10)110(
/G/F
lt
/?
(2) Noise temperature after atmospheric attenuation
T
net
 = T
s
 
10
10
/L
a
?
 + (1 
10
10
/L
a
?
) T
a
(3) Noise temperature after rain attenuation
T
net
 = T
net
 10
-A/10
 + (1  10
-A/10
) T
r
(4) Noise temperature with illumination inefficiencies
T
net
 = T
net
 E
i
 + (1 E
i
) T
b
(5) Noise temperature with dissipation inefficiencies
T
net
 = T
net
 E
d
 + (1 E
d
) T
p
(6) Resulting noise temperature of the system at the input to the LNB
T
A
 = T
net
 + T
eff 
            (K)
Step 3:  Calculate the C/N value associated with rain loss A
CN
A
 = EIRP
sat
 L
Sfree
 L
pt
 L
a
 + [G/T
A
]  k  10 log W
n
  A
where [G/T
A
] = G
Lr
 (?
r
, ?
r
)  10 log T
A  .
Note: clear-sky corresponds to A = 0.  The clear-sky CN
0
 and clear-sky system temperature
T
0
 are also determined in this step.
2-6
Step 4:  System carrier-to-noise plus interference power ratio is a function of A and is
evaluated according to the following expression:
{ }
10710101010
1010101010log10
)/Xmf(CI/CN/CN/CI/CN
sys
ThMCUBA
(A)CNI
++?????
++++?=
here CI
M
 is set to a large value, say 90 dB, in the absence of MVDDS.
(See Section 3.3.2 for rationale of including mf
Th
 and X7 as calibration factors.)
Step 5:  The rain margin A
Rm
 is the value of A that drives the difference between CNI
sys
 (A)
and CNI
Th
 to zero, i.e.,
CNI
sys
 (A
Rm
) = CNI
Th         
.
Note: A
Rm
 is determined through an iterative process over the value of A within Step 2 and
Step 5.   The value of CN
ARm
 (i.e., value of CN
A
 with A=A
Rm
) is also recorded in this step.
Step 6:  The p
Rm
 (%) time of an average year associated with the rain margin A
Rm
 is
determined from the ITU-R Recommendation P.618-6 via the following expression:
)e)p(?A.p..(
Rm
.Rm
dRm.Rm
.
p
AA
sin1ln0450ln03306550
010
010
010
???+?
?
?
?
?
?
?
=
where ? = 0 if p
Rm
 ? 1(%) or ?B
D
? ? 36,
? = -0.005 (?B
D
? - 36) if p
Rm
 < 1(%) and ?B
D
? < 36 and e
d
 ? 25,
? = -0.005 (?B
D
? - 36) + 1.8  4.25 sin e
d
 otherwise.
Note: p
Rm
 can also be interpreted as the percentage time of DBS-downlink outage due to rain.
Step 7:  Calculate the system availability (%)
SAV = 100  p
Rm
         (%).
Step 8:  Calculate the time of system service outage per average year associated with p
Rm
:
U
0
 = 365 * 24 * 60 * 
100
Rm
p
 minutes.
Step 9:  If the MVDDS interference increases the service outage time by V(%) of U
0
:
1. The increase of service outage time per average year is:
?U = U
0
 * 
100
V
         minutes.
2. The total time of service outage per average year is:
U
total
 = U
0
 * )
100
1(
V
+     minutes.
2-7
3. The total percentage time of service outage thus becomes:
p
total
 = 
6024365 **
U
total
 * 100 = p
Rm
 * )
100
1(
V
+        (%)
Step 10:  Apply P.618-6 again to determine the effective rain margin, A
eRm
, associated with
p
total
A
eRm
 = A
0.01
 
)e)p(?A.p..(
total
dtotal.total
.
p
sin1ln0450ln03306550
010
010
???+?
?
?
?
?
?
?
Step 11:  Determine the value of CN
A
 when A = A
eRm
CN
AeRm
 = CN
0
  A
eRm
  10 log
?
?
?
?
?
?
?
?
0
T
T
AeRm
where T
AeRm
 is the value of T
A
 with A = A
eRm
.
Step 12:  Thus CI
MV
 : the value of carrier-to-MVDDS interference power ratio (CI
M
) needed
to effect a change of the rain margin from A
Rm
 to A
eRm
 is given by:
CI
MV
 = 10 log { } ()71010
1010
Xmf
Th
/-CN/CN
AeRmARm
+??
?
Step 13:  The value of CI
M
 in general is calculated, at each grid point position, as:
CI
M
 = EIRP
sat
  L
Sfree
  L
pt
  A
Rm
  L
a
 + G
Lr
 (?
r
, ?
r
) ?+?
MfreeM
LP
10 log{}
?
?
?
?
?
?
?
?
?
?
?
?
?
?
++
++
D
M
)],?(?G),?(?[G)],?(?G),?(?[G
W
W
,
ii
r
Vtt
t
Vii
rHtttH
log100max1010
1010
where L
Mfree
 = 32.44 + 20 log (f
MHz
) + 20 log R
M
 .
Note:  The geographical area of interest (neighborhood extending from the MVDDS tx to the
possible DBS rx locations) is divided by grids with the grid points identified.
Step 14:  Record the calculated values of CI
M
 on the respective grid point positions.
Step 15:  Extract the contour of CI
M
 = CI
MV
 that associates with the V (%) outage increase
due to MVDDS.
Step 16:  To obtain contour of constant V, the following calculations are performed:
1. At each grid point position, based on the computed CI
M
 value, determine the
corresponding value of V by reversing the procedure that has been adopted to
evaluate CI
MV
.
2-8
2. Record these derived values of V on the respective geographical grid positions.
3. Extract the contour of V equal to the constant value specified.
Step 17:  Similar procedures are followed to obtain the contours of constant ?U and constant
U
total
, respectively.
Step 18:  To obtain contour of constant clear-air CI
M
, the following calculations are
performed:
1. At each grid point position, (CI
M
)
0
 (i.e., the value of CI
M
 with A
Rm
 set to zero) is
calculated based on the expression of CI
M
 mentioned above.
2. Record the calculated values of (CI
M
)
0
 on the respective grid point  positions.
3. Extract the contour of (CI
M
)
0
 equal to the constant value specified.
2.2  Rain Scatter Interference
In this section we consider the effect of rain scatter induced interference.  Rain scatter
interference occurs when energy that is transmitted from the MVDDS terrestrial terminal into
a rain cell is scattered by the rain cell and the scattered energy is received by the DBS earth
station.  The necessary conditions for this interference to occur are that the main beams of
the terrestrial terminal and the DBS earth station antenna patterns must create a common
volume in which there is rain.
Preliminary analyses indicate that rain scattered interference is most likely to occur when
the DBS antenna has a low look angle and the DBS beam goes through the main beam of the
MVDDS transmit pattern at a point relatively close to the MVDDS transmitter.  This implies
a geometry such that the DBS antenna would be northeast or northwest of the MVDDS
transmitter, and pointed nearly at the transmit antenna.  It appears that, as long as the
MVDDS transmitter has an EIRP no greater than 14 dBm, then regions of interference on the
ground will be relatively small.  For a 14 dBm EIRP, we expect the region of interference to
be only tens of meters in diameter.
3-1
Section 3
Receiver Susceptibility
3.1  Theoretical Analysis and Predictions
In this section, the results of the simulation analysis used to quantify the degradation of
the Direct Broadcast Satellite (DBS) service due to the Multichannel Video Distribution and
Data Service (MVDDS) system are presented.  This section is organized as follows: Sections
3.1.1-3.1.5 present an overview and a description of the simulation model and lists the
system assumptions.  The model validation is presented in Section 3.1.6.  Sections 3.1.7-
3.1.10 present a summary of the simulation results.
3.1.1  Simulation Model Description
A simulation model of the DIRECTV and EchoStar waveforms was developed using the
Signal Processing Workstation (SPW) modeling tool.  SPW is a powerful software package
used for developing models of advanced waveforms.  The high-level simulation model used
for this analysis is depicted in Figure 3-1 below.  The model consists of four primary blocks,
as illustrated in Figure 3-1, namely, the DBS transmitter, a satellite channel, the DBS
receiver, and the MVDDS interferer.  Each of these four blocks is discussed individually in
the following paragraphs.  The details of each of these components were extracted from
references (European Telecommunication Standard [ETS], 1994; Barker, 31 January 2001;
ITU, 2001).
It should also be noted that simulations were not performed at quasi-error free bit error
rate (BER) (assumed to be 10
-10
) due to unreasonably long simulation runtimes.  Instead,
simulations were performed down to approximately 10
-6
 or 10
-7
, and the results were
extrapolated to compute the BER at 10
-10
.  Given the steepness of the curves, this should
provide a relatively accurate estimate.
DBS
Transmitter
MVDDS
Interferer
DBS
Receiver
Satellite
Channel
Figure 3-1.  Top Level Simulation Model
3-2
3.1.2  DBS Transmitter
The DBS transmitter model is depicted in Figure 3-2.  The model consists of a standard,
concatenated Reed Solomon and convolutional encoder.  A convolutional interleaver is
inserted between the two encoders to disperse burst errors generated at the output of the
Viterbi decoder.  The encoded bits are sent into a quadrature phase shift keying (QPSK)
modulator followed by a square-root raised cosine filter.  The specific details of the code
rates, interleaver sizes, and filter bandwidths are highlighted in Table 3-1.
Bit
Generator
R/S
Encoder
Interleaver
Convolutional
Encoder
QPSK
Modulator
Square-Root
Raised Cosine
Filter
U/L Signal
Figure 3-2.  DBS Transmitter Model
Table 3-1.  Transmitter Model Parameters
Parameter EchoStar DIRECTV
Reed Solomon Code Rate 188/204 130/146
Convolutional Code Rate 3/4 6/7
Viterbi Decoder Soft, 3-bit Soft, 3-bit
Interleaver 12x17 Convolutional -
Forney
146x13 Convolutional -
Ramsey Type II
Square Root Raised Cosine
Filter Rolloff Rate
0.2 0.2
3.1.3  Satellite Channel
The satellite channel consists of an input multiplexer (IMUX) filter, memoryless
nonlinearity, and an output multiplexer (OMUX) filter as depicted in Figure 3-3.  The IMUX
and OMUX filters are based on the Input and Output Multiplexer data found in reference
(ETS, 1994) and are depicted in Figure 3-4.  The amplitude modulation (AM)/AM and
AM/phase modulation (PM) characteristics are based on a standard SPW satellite traveling
wave tube amplifier (TWTA) model and are also depicted in the figure.
3-3
IMUX
Filter
OMUX
Filter
Memoryless
Nonlinearity
Figure 3-3.  Satellite Channel Model
-4 -3 -2 -1 0 1 2 3 4
x 10
7
-60
-40
-20
0
Frequency
A
m
p
l
it
ude
 R
e
s
p
-4 -3 -2 -1 0 1 2 3 4
x 10
7
0
1
2
3
4
x 10
-8
Frequency
G
r
o
up D
e
lay
-4 -3 -2 -1 0 1 2 3 4
x 10
7
-40
-30
-20
-10
0
Frequency
A
m
pl
i
t
ud
e R
e
s
p
-4 -3 -2 -1 0 1 2 3 4
x 10
7
0
1
2
3
4
x 10
-8
Frequency
G
r
oup
 D
e
l
a
y
-25 -20 -15 -10 -5 0 5 10
-20
-15
-10
-5
0
Input Amplitude (dB)
O
u
t
put
 A
m
pl
it
ude (
d
B
)
-25 -20 -15 -10 -5 0 5 10
0
20
40
60
Input Amplitude (dB)
P
has
e S
h
i
f
t
 (
deg)
Figure 3-4.  Satellite Filter Characteristics
3.1.4  DBS Receiver Model
The model for the DBS receiver is depicted in Figure 3-5.  The block diagram shows that
the downlink signal is first summed with additive white Gaussian noise to achieve a specified
C/N ratio, followed by a square-root raised cosine receive filter with the identical properties
as the transmit filter.  The filtered signal is then demodulated through a static phase rotation.
The received phase was determined through an offline cross correlation between the received
signal and the original signal.  Explicit carrier recovery was not modeled since this analysis
is intended to assess the steady state performance of the waveform.  If a carrier-tracking loop
was explicitly included in the model, this would unavoidably inject a component of phase
jitter into the received signal.  The effects of carrier-tracking phase jitter, as well as other
sources of phase jitter are accounted for in a more controlled fashion by injecting a fixed 2
3-4
degrees root mean square (RMS) phase noise prior to the demodulator.  This phase noise is
intended to account for phase noise accumulated in the transmitter, satellite channel, and
receiver.
The demodulated signal is then sent through a 3-bit soft decision Viterbi decoder,
deinterleaver and a Reed Solomon decoder.  Bit error rate monitors were placed at the output
of the Viterbi and Reed Solomon decoders to measure the bit error rate at the output of both
decoders.
Square-Root
Raised Cosine
Filter
Phase
Noise
QPSK
Demod
Viterbi
Decoder
Deinterleaver
+
AWGN
D/L Signal
BER
Monitor
R/S
Decoder
BER
Monitor
Phase
Rotation
Figure 3-5.  DBS Receiver Model
3.1.5  MVDDS Interferer
The MVDDS interfering signal was modeled identically as the DBS waveform described
above.  In order to improve the simulation run time efficiency, the convolutional encoding
and Reed-Solomon encoding in the interfering waveform were excluded.  We believe that the
coders have no statistical significance on the effects of the interferer.  The interfering signal
was thus simply modeled as a QPSK modulated signal passed through a square-root raised
cosine filter.
3.1.6  Simulation Validation
This section discusses the model validation.  Simulation results are compared with
theoretical results, laboratory measurements, and ITU documentation of EchoStar (Dish
Network) and DIRECTV requirements.  However, the results provided by each of these
sources were expressed in terms of C/N ratio where the noise power was computed using
different bandwidths.  Consequently, a direct comparison of C/N results is not valid and will
lead to incorrect conclusions. To make an accurate comparison, all C/N values were first
converted to E
b
/N
0
 using the following equation, and the values computed in Table 3-2.
?
?
?
?
?
?
?
?
?
?
?
?
?
?
=
?
?
?
?
?
?
?
?
RateDataUncoded
Bandwidth
N
C
N
Eb
0
3-5
Table 3-2.  Calculation of (C/N) to (Eb/N
0
) Conversion Factors
DIRECTV 6/7 EchoStar 3/4 Comments
1 Conv Code Rate 0.857 0.750
2RS Code Rate 0.890 0.922
130/146 for DIRECTV and
188/204 for EchoStar
3 Framing Efficiency (Eta) 0.993 0.928
Portion of the uncoded data
rate that is available for
information (accounts for
bits used to accomplish
framing, etc.)
4 Information Bit Rate (Rb) 30.320 27.650
See References (Barker, 31
January 2001; ITU, 2000)
5 Channel Symbol Rate (Rs) 20.001 21.554
Row 4/ (2*Row 1*Row 2*
Row 3)
6ITU BW Factor 1.200 1.280
See References (Barker, 31
January 2001; ITU, 2000)
7 Uncoded data rate (Rb/Eta) 30.531 29.795
Data rate at the input of the
convolutional coder Row 4/
Row 3
8BW (Lab) 20.000 20.00 Measured
9BW (ITU Meas) 24.002 27.589 Row 5 * Row 6
10 BW (Sim) 20.001 21.554 Row 5
11 Uncoded Data Rate/Lab BW (dB) 1.837 1.731 Row 7/Row 8
12 Uncoded Data Rate/ITU Meas BW (dB) 1.045 0.334 Row 7/Row 9
13 Uncoded Data Rate/Sim BW (dB) 1.837 1.406 Row 7/Row 10
Figures 3-6(a) and (b) illustrate the theoretical simulated performance of the EchoStar
and DIRECTV modems with and without convolutional coding.  The simulated performance
of both systems is observed to agree quite closely with the theoretical bounds also depicted
within the figures.  Figure 3-6(c) depicts the modem performance with concatenated
convolutional and Reed Solomon coding.  Simulated performance was always well within
the theoretical bound and the two agree very well at low BER values, although the curves do
diverge at high BER as expected.
Figure 3-6(d) presents the performance of the DBS waveforms through the satellite
channel without interference.  Reference (ETS, 1994) indicates that the required E
b
/N
0
 for
quasi-error free (QEF) performance, assumed to be a BER of 10
-10
, for the EchoStar (3/4
rate) and DIRECTV (6/7 rate) modem is 5.5 dB and 6.2 dB respectively.  These numbers
include 0.8 dB of modem implementation loss, but do not include any losses introduced at
the satellite.  Reference (ITU, 2000) indicates that the worst case implementation loss from
the satellite channel is an additional 1.0 dB. Combining the satellite implementation losses
with the modem performance, results in a required E
b
/N
0
 of 6.5 dB and 7.2 dB respectively
for the EchoStar and DIRECTV waveforms.  One can see that in both instances, the
3-6
simulated performance without interference is within or at this bound (see Figure 3-6(d)).
Note that these implementation losses are quoted worst case and that performance variations
will occur, so the deviation between worst case and simulated is expected.
The simulation results also compare reasonably well with the minimum required C/N
ratios cited in reference (Barker, 31 January 2001).  The document indicates a required C/N
for QEF operation of 6.1 dB and 7.6 dB for the EchoStar and DIRECTV systems
respectively.  Using the conversion factors computed in Table 3-2 for ITU-defined
bandwidths (Row 12), these C/N requirements equate to an E
b
/N
0
 of 5.8 dB and 6.6 dB.  As
can be seen from Figure 3-6(d), the simulation results agree within tenths of a dB for both
systems.
4 5 6 7 8 9 10
10
-5
10
-4
10
-3
10
-2
10
-1
Eb/No (dB)
Bi
t
 Er
r
o
r
 R
a
t
e
QPSK - Sim   
QPSK - Theory
(a)  QPSK Performance
1 2 3 4 5 6 7
10
-5
10
-4
10
-3
10
-2
10
-1
10
0
Eb/No (dB)
B
i
t E
r
r
o
r
 R
a
te
DIRECTV          
6/7 Conv - Theory
EchoStar         
3/4 Conv - Theory
(b)  Convolutional Coding Performance
1 2 3 4 5 6
10
-10
10
-8
10
-6
10
-4
10
-2
10
0
Eb/No (dB)
Bi
t
 Er
r
o
r
 R
a
t
e
DIRECTV        
6/7 RS - Theory
EchoStar       
3/4 RS - Theory
(c)  Concatenated Coding
3 4 5 6 7 8
10
-10
10
-8
10
-6
10
-4
10
-2
10
0
Eb/No (dB)
Bi
t
 Er
r
o
r
 R
a
t
e
DIRECTV              
DIRECTV - Required   
DIRECTV - Worst Case 
EchoStar             
EchoStar - Required  
EchoStar - Worst Case
(d)  Performance through Satellite Channel
Figure 3-6.  EchoStar and DIRECTV Theoretical Performance
3-7
3.1.7  Simulation Results
Simulations were performed for two different sets of waveform characteristics as
indicated in the simulation model section.  Each set of simulations showed the same basic
trends and conclusions.  These results are discussed below.
3.1.8  EchoStar Simulated Performance
The BER results for the EchoStar waveform (3/4 convolutional coding, 188/204 RS
coding) in the presence of various levels of interference are shown in Figure 3-7(a).  Without
interference, the system is able to achieve QEF operation at an E
b
/N
0
 of approximately 6.2
dB.  The same curve was also generated in the presence of three levels of interference.  For
N/I ratios of 10, 5, and 0 dB, the performance was degraded by 0.4, 1.0, and 2.4 dB
respectively.
These same results are also plotted in Figure 3-7(b) against C/(N+I), where the noise
power was computed over the simulation bandwidth (channel symbol rate).  Again,
comparing these C/N results with other sources that assume different bandwidth definitions is
invalid.  One should use the conversion factors shown in Table 3-2 to convert C/N to E
b
/N
0
before attempting any such comparison.  Note that the required C/(N+I) is about 0.5 dB less
when the noise and interference powers are equal.  To accommodate this, the C/(N+I)
threshold value should be thought of as a function of the N/I ratio.  See Section 3.3 for a
further discussion of the threshold used in the system analysis tool.
The results indicate that performance improves as the ratio of N/I is decreased.  A
common assumption in many interference link budgets is that noise and interference are
additive; that is, they are equally detrimental to system performance.  If that were true, the
BER would depend only on the total (N+I) power, and the BER versus C/(N+I) curves would
be identical regardless of N/I ratio.  Instead, it is observed that the performance curves
improve as the N/I ratio decreased.  For example, assume that the signal power is 1 watt and
the (N+I) power is 0.25 watts.  The resulting BER with noise power of 0.25 watts and
interference power of 0 watts (C/(N+I) = 6 dB) is worse than the BER with noise power of
0.125 watts and interference power of 0.125 watts (C/(N+I) = 6 dB).  The conclusion is that
for these signal, noise, and interference characteristics, the noise is more detrimental to
system performance than interference.  It is thus actually conservative to replace the
interferer by an Additive White Gaussian Noise (AWGN) source of equal average power in
system performance calculations. This basic conclusion was also verified with theoretical
calculations; see the theoretical explanation provided in Section 3.1.11.
It should also be noted that additional simulations were performed to examine the impact
of phase noise and traveling wave tube (TWT) backoff since the specific values for these
parameters were unknown.  Simulation results were not sensitive to these factors, and the
trends/conclusions discussed above remain valid.
3-8
3 4 5 6 7 8 9
10
-10
10
-8
10
-6
10
-4
10
-2
10
0
Eb/No (dB)
B
i
t
 E
rro
r 
R
a
t
e
No Int  
N/I=10dB
N/I=5dB 
N/I=0dB 
(a)
4.5 5 5.5 6 6.5 7 7.5 8
10
-10
10
-8
10
-6
10
-4
10
-2
10
0
C/(N+I) (dB)
Bi
t
 E
r
r
o
r
 R
a
t
e
No Int  
N/I=10dB
N/I=5dB 
N/I=0dB 
(b)
Figure 3-7.  EchoStar Simulation Results with Interference
3.1.9  DirectTV Simulated Performance
The trends for the DIRECTV simulation performance are similar to those shown for
EchoStar.  The common conclusion is that interference is less detrimental than noise.  The
results of the DIRECTV simulations are shown in Figure 3-8 below.  As before, C/(N+I) and
E
b
/N
0
 are related by the conversion factors shown in Table 3-2.  Again, we see that the
required C/(N+I) is about 0.8 dB lower for an N/I of 0 dB.
5 6 7 8 9 10
10
-10
10
-8
10
-6
10
-4
10
-2
10
0
Eb/No (dB)
B
i
t
 E
rro
r R
a
t
e
No Int  
N/I=10dB
N/I=5dB 
N/I=0dB 
(a)
6.5 7 7.5 8 8.5 9 9.5
10
-10
10
-8
10
-6
10
-4
10
-2
10
0
C/(N+I) (dB)
Bi
t
 E
r
r
o
r
 R
a
t
e
No Int  
N/I=10dB
N/I=5dB 
N/I=0dB 
(b)
Figure 3-8.  DIRECTV Simulation Results with Interference
3-9
3.1.10  Simulation Summary
A summary of the results for the EchoStar and DIRECTV is provided in Table 3-3.  The
table lists the C/(N+I) required to obtain QEF performance at the output of the Reed
Solomon decoder for various levels of N/I (noise power is computed over the symbol rate
bandwidth).  The table indicates an 0.65 dB (EchoStar) and 0.79 dB (DIRECTV)
improvement in the required C/(N+I) as the N/I is decreased from ? to 0 dB.
Table 3-3.  Simulation Results Summary
Required C/(N+I) for QEF
N/I
EchoStar DIRECTV
?
7.60 dB 9.14 dB
10 7.55 dB 9.08 dB
5 7.45 dB 8.90 dB
0 6.95 dB 8.35 dB
3.1.11  Theoretical Explanation
The results obtained with the waveform simulations described above can also be
explained with theoretical calculations.  Assume a QPSK signal in the presence of AWGN
where the 00 symbol has been transmitted.  The probability density function of the received
signal is a two dimensional Gaussian distribution centered around the intended 00 symbol
(see Figure 3-9).  The relative width, or variance, of this distribution is determined by the
C/N ratio.
00
11
01
10
Real
Imag
Figure 3-9.  Probability Density Functions of Received QPSK Signal
3-10
To calculate BER, one would simply calculate the probability that the noise has pushed
the received signal into an incorrect quadrant.  This is accomplished by integrating the
probability density function over the 01, 10, and 11 quadrants:
??????
++=
111001
2
Quad
xy
Quad
xy
Quad
xy dydxfdydxfdydxfBER
NOTE:  Because the symbol 00 was transmitted in this example, one bit error would be incurred if the received
symbol were a 01 or 10, and two bit errors would be incurred if the received symbol were a 11.  Hence, the
coefficient for the third integral is a two.
Since interference has different statistical properties than AWGN, this integration will
yield different results for noise and interference scenarios.  Take the example shown in
Figure 3-10.  The density functions are compared for noise only (noise power = P
T
,
interference power = 0), interference only (noise power = 0, interference power = P
T
), and
half noise/half interference (noise power = P
T
/2, interference power = P
T
/2).  In all three
cases, the total power of noise + interference remains constant.  However, the statistical
properties of the degrading signal have been altered significantly.  In fact, the QPSK
interference (which has an equal probability of being in one of four different states) tends to
concentrate the density function.  Consequently, the probability of obtaining a high enough
value to cause an error decreases.  This is shown in Figure 3-11, which illustrates the BER
obtained by integrating the density functions in Figure 3-10.
Note that the noise only BER is 10
-5
 at a S/N ratio of 12.6 dB (Eb/N
0
 of 9.6 dB) as
expected.  It is also clear that the noise only scenario demonstrates worse performance than
the half noise/half interference scenario (assuming total noise + interference power remains
constant).  That is, noise is more detrimental to system performance than this type of
interference.  This corroborates the trends that were observed in the waveform simulations,
although the degree of improvement will depend on many other factors such as satellite
distortions, coding, etc.
3-11
Probability density function
(Noise Only)
Probability density function
(Noise = Interference)
Probability density function
(Interference Only)
It is extremely subtle but when interference is
mixed with noise, the interference has the
impact of condensing the probability density
function.  Hence, the probability of a high
enough value to cause an error decreases.
Cross-section of probability density functions
-4 -3 -2 -1 0 1 2 3 4
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
N Only
N = I 
Figure 3-10.  Probability Density Functions of Noise and Interference
0 2 4 6 8 10 12
10
-5
10
-4
10
-3
10
-2
10
-1
10
0
S/(N+I) (dB)
BER
Noise Only (Noise = Pt, Interference = 0)      
N/I of 0 dB (Noise = Pt/2, Interference = Pt/2)
Figure 3-11.  QPSK BER as Computed from Numerical Integration of Probability
Density Functions
3-12
3.2  Testing of DBS Set-Top Boxes in the Presence of Northpoint MVDDS
Interference
This subsection provides an overview of the laboratory tests performed to support the
unavailability analysis.  Detailed configurations and techniques are given in Appendix A.
3.2.1  Overview of Test Configuration for Receiver Degradation Measures
A simplified view of the test configuration used to study the impact of MVDDS
interference on DBS systems is shown in Figure 3-12.  In general, a closed DBS link is
perturbed via the insertion of additional interference signals.
Signal quality is monitored through observation of the picture and sound quality as
observed through a television connected to a DBS set-top box.  Signal quality, C/(N+I) or
carrier to noise plus interference ratio is calculated from data measured with an Agilent
8564E spectrum analyzer.  A SAT9250 DBS installers tool was also used to measure C/N
during interference experimentation.
In order to have independent control of both the carrier-to-noise-plus-interference, and
the interference-to-noise power ratios, addition of both Gaussian noise and Northpoint
interference was necessary.
? ?
AWGN
Generator
Interference
Source
DBS Set-top
Box
SAT 9520
Installer's
Tool
Agilent
8564EC
Spectrum
Analyzer
Figure 3-12.  Functional Overview of DBS Video Test Configuration
3.2.2  Standard for Signal Quality Measurement
Due to the nature of the encoded DBS signal, video and audio degradation occurs over a
very narrow region of carrier-to-noise plus interference, C/(N+I), prior to complete loss of
signal lock. Degradation in signal quality originating from a digital broadcast is unlike that
from an analog broadcast, where picture quality is very subjective.  Instead, degradation is
quite noticeable, and occurs in burst fashion when uncorrected bit errors are presented to the
Motion Picture Experts Group (MPEG) decoder.  For low bit error rates, errors are corrected
3-13
by the error correction coding inherent in the system.  Video and audio impairments occur
when the number of bit errors exceeds what is correctable by the concatenated code.  Video
impairments manifest as sudden pixelization in the image.  Audio errors manifest as a sudden
pop or chirp sound.  In general, the rate of audio and video error occurrences increases as the
C/(N+I) ratio degrades.  A video/audio quality criteria was established for the purpose of
assigning a quality measure.  See Table 3-3.
Table 3-4.  DBS Signal Quality Criteria
Assigned Quality Level
(9=Error Free)
Video/audio characteristics
(average)
9 Perfect video/audio
8 1 video/audio error per 30 minutes
7 < 1 error per minute, but > than 1 per 30 minutes
6 < 1 error per 15 seconds, but > 1 error per minute
5 > 1 error per 15 seconds
4 Freeze framing and pixelization  occurring; audio
chirping and momentary blanking
3 Mostly pixelized, mostly frozen, mostly audio
blanked
2 Occasional video acquisition, no audio
1 Loss of lock, no signal acquisition
3.2.3  DBS Signal Quality 6 in the Presence of Northpoint MVDDS Interference Using
12 GHz RF Output with Simulated Adjacent Channels
The data used to support the analytic runs for assessment of increase in DBS
unavailability were taken using the single channel MVDDS transmitter supplied by
Northpoint.  The center frequency of output of this transmitter is selectable to any frequency
within the 12.2-12.7 GHz band.  Simulated adjacent channels were generated via arbitrary
waveform synthesizers and mixed with the down-converted L-Band signal at an appropriate
frequency spacing.
Data is recorded at various noise-to-interference levels, +infinity (noise only) +10 dB, +3
dB, 0 dB, -3 dB, and 10 dB, and infinity (interference only).  Results for +infinity and 
infinity are plotted on the +30 and 30 dB points, respectively.  While holding N/I constant,
the total power of the noise and interference combination was raised until the quality of the
signal was reduced to Signal Quality 6, one video or audio error occurring with an average
arrival rate between 15 seconds and 1 minute.
3-14
The results are shown for DIRECTV and Dish TV in Figure 3-13 and Figure 3-14,
respectively.
A common trend that was observed throughout the testing of the Northpoint MVDDS
transmitters impact to the DBS receiver is the relative resilience to the constant envelope
QPSK MVDDS signal as compared to Gaussian noise.
Note as well the close agreement between the SAT9250 measurement in the noise-only
case and spectrum analyzer measurements.  Insufficient information is available about the
SAT9250 to provide an accurate scaling factor that would account for differences in
measurement bandwidth between the spectrum analyzer and the SAT9250.
DirecTV C/(N+I) Threshold vs. N/I;
Nrthpt Interference w/ Adj Channels + Noise
2
3
4
5
6
7
8
-30 -20 -10 0 10 20 30
N/I (dB)
C/(N+I) Threshold
Figure 3-13.  Carrier-to-Noise-Plus-Interference Required to Degrade DIRECTV to
Signal Quality 6 Vs. Interference-to-Noise Power Ratio; 12 GHz RF Output
3-15
Dish Network C/(N+I) Threshold vs. N/I;
Nrthpt Interference w/ Adj Channels + Noise
2
3
4
5
6
7
8
-30 -20 -10 0 10 20 30
N/I (dB)
C/(N+I) Threshold
Figure 3-14.  Carrier-to-Noise-Plus-Interference Required to Degrade Dish TV to
Signal Quality 6 Vs. Interference-to-Noise Power Ratio; 12 GHz RF Output
3.3  Selection of Threshold Values from Theoretical and Measured Results
There are many things that need to be taken into account when making comparisons
among the simulation, measured, and published threshold performance values.  These
include:
 Different measures of performance
 Different definitions of measurement bandwidth
 Different data rates to consider for any given system in a given mode
The following Sections provide rationale for threshold values chosen for model runs,
including, where appropriate, references to support the numbers quoted.  In Section 3.3.1 we
discuss the values for noise dominated cases whereas in Section 3.3.2 we discuss our
approach for cases dominated by MVDDS interference.
3.3.1  Threshold for Noise Dominated Cases
3.3.1.1  DishTV (EchoStar) Rate 3/4
Data for the threshold value comes from several sources including laboratory
measurements, simulation-based analysis, and published documentation.  Published data in
3-16
this case comes from the answers to the first set of questions posed by MITRE to the DBS
proponents (Barker, 31 January 2001).  This submission includes a copy of ITU-R document
6/35-E, dated 21 September 2000, which comes from source document ITU-R 6S/TEMP/1.
The ITU document gives example rates in Table 1 (Barker, 31 January 2001).  From these
we can deduce that there is a 0.928 framing efficiency.  The remaining 7.2% of the
transmission is used for synchronization and other overhead needed for the satellite
transmission to be successfully received.  Notes to Table 2 in the ITU document (Barker,
31 January 2001) say that a bandwidth (BW) to symbol rate (Rs) ratio of 1.28 has been
adopted.  Ratios of data rates, but not exact data rates, can be deduced from Table 1 of the
ITU document (Barker, 31 January 2001).
Page 3 of the answers to the first set of questions (Barker, 31 January 2001) shows that
the effective data rate is 27.65 Mb/s.  This is also called the information rate.  From this and
the rate ratios deduced from Table 1 of the ITU document, we get:
 Rs = 21.55 Mb/s = 27.65/(2*0.75*(188/204)*0.928)
 Rb = 27.65 Mb/s
 Total signal BW = 25.86 MHz = 1.2*Rs
 ITU measurement BW for C/N = 27.59 MHz = 1.28*Rs
In order to make comparisons to simulation results, we should not penalize the system for
the framing inefficiency.  So, for purposes of comparison with simulation and theoretical
results, we should retain the Rb above, but multiply all other rates and bandwidths by 0.928.
Doing so, and then evaluating the ratio of Rb to the new measurement bandwidth, we get a
factor of 0.33 dB.  ITU C/N values should be reduced by this amount to get a comparison
ready E
b
/N
0
 value (see Table 3-2).
The ITU document lists a C/N of 6.8 dB (Barker, 31 January 2001).  However, pages 3
and 5 of the answers to the first set of questions say 6.1 dB (Barker, 31 January 2001).  These
values imply an E
b
/N
0
 of between 5.8 and 6.5 dB.  A value of 6.4 dB was chosen for the
system analysis model.  This is within the range of values stated, but is slightly conservative.
To summarize, the E
b
/N
0
 values for QEF performance are provided in Table 3-5 below.  The
DIRECTV system will be discussed in Section 3.4.1.2.
To obtain a C/N value for the system analysis, we must convert from the E
b
/N
0
 values to
a C/N measured in the appropriate bandwidth.  Here we use 20 MHz as the noise bandwidth.
For a system operating at the information rate of 27.65 Mb/s, with no framing inefficiencies,
and an E
b
/N
0
 performance of 6.4 dB, its C/N value measured in a 20 MHz bandwidth would
be 7.8 dB.  Correcting for the framing inefficiencies, we get 8.1 dB C/N in a 20 MHz
bandwidth for the real system with QEF performance.
3-17
Table 3-5.  Summary of Eb/No for QEF Performance (dB)
EchoStar 3/4 DIRECTV 6/7
ETS Standard
(ETS, 1994)
6.5
ITU document
(Barker, 31 January 2001)
5.8 6.6
DBS Answers
(Barker, 31 January 2001)
6.5 6.6
Simulation Results 6.2 7.2
Value Used in System
Analysis
6.4 6.6
Now we turn from published and simulated results to laboratory results. Laboratory
measurements were based on a 20 MHz bandwidth for noise power measurements.  The
signal was measured in the same 20 MHz bandwidth, but scaled by 0.2 dB to account for the
tails of the spectrum.  Graphical depiction of the test results will be presented in Section
3.3.2.  Averaging the lab test results for the intermediate frequency (IF) measurement case
(but leaving out the Northpoint dominated case) we get an average C/N of 5.7 dB for video
quality of 6.  The 12 GHz tests produce a C/N value of about 5.0 dB in noise for video
quality of 6 or 7.  Compromising between theses two values, we pick a value closer to the
results of the IF tests because it represents more data points.  In summary we use the
following C/N threshold values for the EchoStar system:
 Quasi Error Free:  C/N = 8.1 dB
 Video Quality 6:  C/N = 5.5 dB
Note that the above values are based on noise measured in a 20 MHz bandwidth, not
24 MHz.  Both cases above will be run in the system analysis model.
3.3.1.2  DIRECTV Rate 6/7
Using a similar approach to the one for EchoStar, we find that the framing efficiency is
0.9931.  Rates and bandwidths are:
 Rs = 20 Mb/s
 Rb = 30.32 Mb/s
 Total signal BW = 24 MHz
 ITU measurement BW for C/N = 24 MHz
3-18
The ITU document and the answers to the first set of questions indicate a C/N of 7.6 dB
(Barker, 31 January 2001).  This converts to a comparison read E
b
/N
0
 value of 6.6 dB.
Scaling to obtain a C/N in a 20 MHz bandwidth, we get 8.4 dB.  Turning to the laboratory
measurements, we get an average of 7.5 dB for the IF data set.  The 12 GHz measurements
yield about 7.1 dB in noise.  So, to summarize, we use the following values for the
DIRECTV system:
 Quasi Error Free:  C/N = 8.4 dB
 Video Quality 6:  C/N = 7.3 dB
Again, these C/N values are based on noise measured in a 20 MHz bandwidth.  A similar
analysis produced a set of values for video quality 1.  These C/N values are shown below in
Table 3-6, along with the C/N values discussed above.
Table 3-6.  Summary of C/N Values (dB)
EchoStar 3/4 DIRECTV 6/7
QEF 8.1 8.4
Video Quality 6 5.5 7.3
Video Quality 1 5.1 6.1
3.3.2  Threshold Values for MVDDS Interference Dominated Cases
One interesting result of the laboratory tests, is that the DBS systems seem to be less
susceptible to this type of interference than to noise of the same power.  This is important,
since it implies that the MVDDS signal can be stronger than might otherwise be expected,
for the same interference impact.  From the data, it appears that the required C/(N+I) ratio is
a weak function of the I/N ratio.  Differences of about 1 dB exist over the range of I/N
values.  Figure 3-15 provides an example of this. As seen in the figure, cases where the
interference dominates require a lower C/(N+I) ratio for video quality 6.  In this figure, the
two curves represent two different measurement sets, one with a Northpoint signal coupled at
IF, and one with the Northpoint signal coupled through the low noise block converter (LNB).
This apparent improvement in required C/(N+I) is due to the fact that the interfering
signal does not have the same amplitude distribution as the Gaussian noise.  See Section
3.1.11 for a detailed explanation of this phenomenon.
3-19
DirecTV Threshold at Video Quality 6
5
5.5
6
6.5
7
7.5
8
8.5
-30 -20 -10 0 10 20 30
I/N  (dB)
C/(N+I) Threshold (dB)
NP thru LNB
NP at IF w/ Adj. Ch.
Figure 3-15.  Threshold Improvement
To account for the apparent improvement in threshold value, a model for the threshold
was developed.  This model is as follows:
x
)/x(
)x(
+
+
=
1
1
0

?? (1)
Where:
?(x)= the threshold C/(N+I) value as a function of x, for a particular video quality
x = the I/N ratio
?
0
 = the nominal C/N value for noise dominated cases
 = a factor that accounts for reduced susceptibility of the DBS system to interference
This model provides a way to embody the results of the tests and a means to interpolate
among values of I/N.  The model is plotted below along with data from numerous laboratory
tests.  Figure 3-16 shows the results for DIRECTV and Figure 3-17 shows the results for
Dish TV (EchoStar).  In both cases, the model uses a  value that corresponds to a 1.0 dB
3-20
reduction in required C/(N+I) for interference dominated cases.  In Figure 3-17, note that the
data from the arbitrary waveform synthesizer (AWS) seems less reliable at large values of
I/N.  Hence, we ignored these results in selecting .
DirecTV Threshold at Video Quality 6
5
5.5
6
6.5
7
7.5
8
8.5
-30 -20 -10 0 10 20 30
I/N  (dB)
C/(N+I) Threshold (dB)
AWS, -45 dBm
AWS, -55
NP thru LNB
NP at IF w/ Adj. Ch.
NP at IF
Model
Figure 3-16.  Laboratory Data and Threshold Model for DIRECTV
3-21
Dish TV (EchoStar) Threshold for Video Quality 6
3.5
4
4.5
5
5.5
6
6.5
7
-30 -20 -10 0 10 20 30
I/N Ratio (dB)
C/(N+I) Threshold (dB)
NP, w/ Adj. Ch.
NP thru LNB
NP, -55 dBm
NP, -30 dBm
AWS, -55 dBm
AWS, -30 dBm
Model
Figure 3-17.  Laboratory Data and Threshold Model for Dish TV
The above model is applied to the analysis of allowable interference levels in the
following way.  In order for the link to operate at video quality, the following inequality must
be satisfied:
)A(NI
)A(C
)x(
+
?? (2)
Where:
?(x)= the threshold value, as in equation 1 above
C(A) = the received carrier power, as a function of the rain attenuation, A
A = the rain attenuation
I = the interference power
N(A) = the noise power, as a function of the rain attenuation, A
3-22
For a given interference power, equation 2 could be solved for the rain attenuation, A.
This rain attenuation corresponds to a particular unavailability for the DBS system.
Combining equations 1 and 2 and using x = I/N, after some algebra, we get:
)A(N)/I(
)A(C
+
?

?
0
(3)
This expression can also be solved for the rain loss, A.  Hence the analysis model scales
the interference power by the quantity  in evaluating the link unavailability.
In addition to the laboratory tests conducted with the interference centered on the DBS
signal, tests were also run with an offset of 7 MHz.  This results in an additional reduction in
required C(N+I) threshold values.  Test results are shown in Figure 3-18 along with a model
for the threshold value.
DirecTV Threshold at Video Quality 6
5
5.5
6
6.5
7
7.5
8
8.5
-30 -20 -10 0 10 20 30
I/N  (dB)
C/(N+I) Threshold (dB)
NP thru LNB
NP at IF w/ Adj. Ch.
NP, 7 MHz offset
0 MHz Model, 1.0 dB Offset
7 MHz Model, 1.5 dB Offset
Figure 3-18.  Data and Threshold Model for 7 MHz Offset
As shown in the figure, the threshold for the 7 MHz offset case is 1.5 dB below the
threshold for noise alone.  Also, there is an additional 1.2 dB delta, since the interference
values used in the figure are based on power measurements centered on the DBS signal.  The
difference between the total interference power and the power measured in a 20 MHz band
3-23
centered on the DBS signal is 1.2 dB.  So, for the 7 MHz offset case, a total correction of 2.7
dB is needed.  In the system analysis model, the factor of 2.7 dB is implemented in two parts.
First, a 1.0-dB factor is used for all cases.  An additional 1.7 dB is used for cases with the
7-MHz offset.  Inputs to the system analysis model are summarized in Table 3-7 below.
Table 3-7.  System Model Threshold Improvement Factors
Frequency Offset
(MHz)
Interference
Factor (dB)
Frequency Offset
Factor (dB)
Total Factor
(dB)
0 1.0 0.0 1.0
7 1.0 1.7 2.7
These factors are used in the basic analysis model that evaluates the impact of MVDDS
interference.
4-1
Section 4
Antenna Patterns
4.1  MVDDS Antenna Patterns
The gain and radiation patterns were measured in the D720 anechoic chamber using a
spherical near-field scanner.  The scanner was procured from Nearfield Systems Incorporated
(NSI).  It is commonly used indoors where it would be impractical to make far-field
measurements.  Indoor measurements offer the advantage of performing measurements
during bad weather.  The absorber-lined anechoic chamber minimizes reflections from the
walls and ceiling.  The near-field technique has been studied extensively, and it is an
accepted method for measuring antenna gain and radiation patterns (Evans, 1990;
Slater, 1991).
Although the scanner is capable of planar and cylindrical scans, a spherical scan was
chosen because of our interest in covering as much of the sphere of observation as possible.
Referring to Figure 4-1 the antenna is mounted on a spherical near-field scanner consisting of
two axes of rotation.  An absorber-covered beam supports one positioner that rotates the
antenna under test (AUT) in azimuth with respect to the AUTs coordinates.  The second
positioner rotates the AUT and supporting beam in elevation with respect to the AUTs
coordinates.
The probe on the left is stationary for spherical scans.  The probe samples
electromagnetic fields over a spherical surface surrounding the AUT.  A Hewlett-Packard
8530 network analyzer measures the sampled fields.  For all AUT measurements shown here
the probe is a WR-75 open-end waveguide.  The polarization of the probe is horizontal,
initially, then it is rotated 90 degrees to obtain the vertical polarization response of the AUT.
The NSI software processes these measurements to obtain far-field AUT response.
Antenna gain is obtained by the gain substitution method.  In this method the AUT is
measured, then a second antenna is measured whose gain is known beforehand.  By
comparing the relative response of the two antennas, the gain of the AUT can be determined.
The gain standard antenna used here is an EMCO model 3160-08 smooth-wall pyramidal
horn.
To obtain radiation patterns over the entire sphere of observation, it is necessary to
measure the patterns in two pieces.  The scanner is capable of moving the AUT over the full
sphere; however, the absorber-covered beam blocks the pattern behind the antenna.  To get
around this problem the antenna is pointed away from the probe, and a second scan is
performed.  The antenna is elevated over the absorber-covered beam such that the main beam
of the AUT clears the absorber.  This is done to minimize the disturbance of the field behind
4-2
the antenna due to high-intensity fields impinging on the absorber.  Figure 4-14 shows an
example of a mount designed for measuring fields behind an AUT.
Once these two roughly hemispherical scans are obtained, they must be processed so that
the observation angles and polarization vectors are consistent between the two
measurements.  In order to do this the coordinate system of the behind the antenna scan is
rotated using a rotation matrix based on Euler angles, and the polarization vectors are
transformed by calculating dot products based on the same rotation matrix.
The polar plots that follow depict radiation patterns in the two principal planes of the
antenna, that is, azimuth and elevation through the main beam of the antenna.  The azimuth
patterns are based on a top down view of the antenna with the main beam pointing up.  The
elevation patterns are based on a side view of the antenna with the main beam pointing to the
right.  Although patterns were measured at 12.2, 12.45, and 12.7 GHz, only patterns
measured at 12.45 GHz are included here.
4.1.1  Small Sectoral Horns
The small Northpoint H-plane sectoral horn is shown in Figure 4-1 as it was measured in
the anechoic chamber.  The sectoral horns are used with the flare vertical so that a broad
azimuthal pattern with horizontal polarization is generated.  Figure 4-2 shows an azimuth cut
with a similar measurement provided by Pegasus for its own small horn.  Figure 4-3 shows a
Northpoint elevation cut measured by MITRE only.  One can see that the azimuth pattern is
very broad, and the elevation pattern is comparatively narrow.
Figure 4-1.  Small Sectoral Horn on Spherical Scanner
4-3
-60
-50
-40
-30
-20
-10
0
10
20
0
30
120
150
180
210
240
270
300
330
Azimuth Cut Small Sectoral Horn
Horizontal Pol 12.45 GHz
Northpoint
Pegasus
G
a
in
 (
d
B
il)
Figure 4-2.  Azimuthal Radiation Patterns of Small Sectoral Horns
-60
-50
-40
-30
-20
-10
0
10
20
0
30
60
90
120
150
180
210
240
330
Elevation Cut Small Sectoral Horn
Horizontal Pol 12.45 GHz
G
a
in
 (
d
B
il)
Figure 4-3.  Elevation Radiation Pattern of Northpoint Small Sectoral Horn
4-4
4.1.2  Large Sectoral Horns
The large Northpoint H-plane sectoral horn is shown in Figure 4-4 in the anechoic
chamber.  Figure 4-5 shows an azimuthal cut with a similar measurement provided by
Pegasus for its own large horn, and Figure 4-6 shows the corresponding Northpoint elevation
cut.  It is evident that in this case the Northpoint and Pegasus antennas have very similar
main-beam patterns in the azimuthal plane.  The elevation beamwidth is narrower than that
for the small-sectoral horn.
Figure 4-4.  Large Sectoral Horn on Spherical Scanner
4-5
-60
-50
-40
-30
-20
-10
0
10
20
0
30
120
150
180
210
240
270
300
330
Azimuth Cut Large Sectoral Horn
Horizontal Pol 12.45 GHz
Northpoint
Pegasus
G
a
in
 (
d
B
il)
Figure 4-5.  Azimuthal Radiation Patterns of Large Sectoral Horns
-60
-50
-40
-30
-20
-10
0
10
20
0
30
60
90
120
150
180
210
240
330
Elevation Cut Large Sectoral Horn
Horizontal Pol 12.45 GHz
G
a
in
 (
d
B
il)
Figure 4-6.  Elevation Radiation Pattern of Large Northpoint Sectoral Horn
4-6
4.2  DBS Antenna Patterns
The feed horn used on the DIRECTV antennas is integral to the LNB.  In order to
perform coherent measurements on these antennas, it was necessary to remove the LNB
circuit board and replace it with an adapter that would allow us access to the Ku-band signal.
The MITRE machine shop fabricated a fixture that connected to the back of the feed horn
and allows a connection to a WR-75 waveguide to sub-miniature A (SMA) coax adapter.
Care was exercised in aligning the adapter probe to the ridge polarizer in the throat of the
feed.  The fixture was oriented such that the horn generates right-hand circular polarization
(RHCP).
4.2.1  DIRECTV 18-inch Reflector
Figure 4-7 shows the DIRECTV 18-inch reflector in the anechoic chamber.  Figure 4-8
shows an azimuth cut.  Note that the dominant polarization is left-hand circular polarization
(LHCP).  This occurs when the RHCP wave flips to LHCP upon reflection from the
reflector.  Figure 4-9 shows the elevation cut.  The large RHCP component near 0 degrees is
due to energy from the feed that bypasses the reflector; this is referred to as spillover.  Figure
4-10 shows a contour plot of RHCP in which the main beam is located at the center.  Theta is
a polar angle, related to elevation, measured from zenith, and phi is azimuth measured from
the main beam.  The horizon is located at theta = 90, zenith at theta = 0, and nadir at theta =
180 degrees.  Observe the comparatively high signal level at zenith and at lower elevations
corresponding to spillover directions.  The strut supporting the feed blocks the spillover near
theta = 90 and phi =  180 degrees.
Figure 4-7.  DIRECTV 18-inch Reflector on Spherical Scanner
4-7
-60
-40
-20
0
20
40
0
30
120
150
180
210
240
270
300
330
Azimuth Cut 18" DirecTV 12.45 GHz
RHCP
LHCP
Ga
i
n
 (
d
Bic)
Spillover
Spillover
Feed Arm Blockage
Figure 4-8.  Azimuthal Radiation Pattern of DIRECTV 18-inch Reflector
-40
-30
-20
-10
0
10
20
30
40
0
30
60
90
120
150
180
210
240
330
Elevation Cut 18" DirecTV 12.45 GHz
RHCP
LHCP
Ga
i
n
 (
d
Bic)
Spillover
Figure 4-9.  Elevation Radiation Pattern of DIRECTV 18-inch Reflector
4-8
Figure 4-10.  RHCP Radiation Pattern of DIRECTV 18-inch Reflector
4.2.2  DIRECTV 24 x 18 Reflector with Single Feed
A multiple feed reflector was measured that is capable of receiving signals from two
satellites in different locations in the geostationary orbit.  The radiation pattern is squinted by
moving the feed away from the focus of the parabolic reflector.  The DIRECTV 24 by 18-
inch reflector can accept feeds at three locations for use with satellites at 101, 110, and 119
degrees West longitude.  The single feed reflector referred to here has the feed located at the
center.  Figure 4-11 shows the azimuth cut.  This antenna has greater spillover than the 18-
inch version as shown by the larger RHCP response about 180 degrees.  Spillover is also
evident in the elevation cut shown in Figure 4-12.  The contour plot in Figure 4-13 shows a
slightly different spillover pattern due to the elliptical contour of the reflector.
4-9
-60
-40
-20
0
20
40
0
30
120
150
180
210
240
270
300
330
Azimuth Cut 18" x 24" DirecTv Single Feed 12.45 GHz
RHCP
LHCP
Ga
i
n
 (
d
Bic)
Spillover
Feed Arm Blockage
Spillover
Figure 4-11.  Azimuthal Radiation Pattern of DIRECTV 24-by-18-inch Reflector
with Single Feed
-60
-40
-20
0
20
40
0
30
60
90
120
150
180
210
240
330
Elevation Cut 18" x 24" DirecTv Single Feed 12.45 GHz
RHCP
LHCP
Ga
i
n
 (
d
Bi
c)
Spillover
Figure 4-12.  Elevation Radiation Pattern of DIRECTV 24-by-18-inch Reflector
with Single Feed
4-10
Figure 4-13.  RHCP Radiation Pattern of DIRECTV 24 by 18-inch Reflector
with Single Feed
4.2.3  DIRECTV 24 by 18-inch Reflector with Dual Feed
In a second measurement of the 24 by 18-inch DIRECTV reflector, two feeds at the outer
positions are measured.  In this case the active feed is on the right when facing the front of
the reflector as shown in Figure 4-14.  Figure 4-15 shows an azimuth cut in which the
spillover is worse on the same side of the reflector as the feed is displaced from the focus.
Spillover appears in the elevation pattern shown in Figure 4-16 around theta = 270 and 345
degrees corresponding to the top and bottom edges of the reflector.  Figure 4-17 shows the
asymmetrical nature of the spillover.  Once again, the spillover is worse on the side where
the feed is located.  Since the feeds in all three positions are parallel, it is intuitively
reasonable that the spillover would be worse in the direction of lateral feed displacement.
4-11
Figure 4-14.  DIRECTV 24-by-18-inch Reflector with Dual Feed on Spherical Scanner
-60
-40
-20
0
20
40
0
30
120
150
180
210
240
270
300
330
Azimuth Cut 18" x 24" DirecTv Dual Feed 12.45 GHz
RHCP
LHCP
Ga
i
n
 (
d
Bic)
More Spillover on This Side
Due to Displaced Feed
Figure 4-15.  Azimuth Radiation Pattern of DIRECTV 24-by-18-inch Reflector
with Dual Feed
4-12
-60
-40
-20
0
20
40
0
30
60
90
120
150
180
210
240
330
Elevation Cut 18" x 24" DirecTv Dual Feed 12.45 GHz
RHCP
LHCP
Ga
i
n
 (
d
Bi
c)
Spillover
Figure 4-16.  Elevation Radiation Pattern of DIRECTV 24-by-18-inch Reflector
with Dual Feed
4-13
Figure 4-17.  RHCP Radiation Pattern of DIRECTV 24-by-18-inch Reflector
with Dual Feed
4.2.4  Fortel
A flat panel antenna produced by Fortel was also measured.  The entire pattern was not
measured, so part of the pattern behind the antenna is missing in the figures below.  Opaque
covers block examination of the radiating elements and combining network, so the exact
nature of this antenna is not known.  Although the LNB can be removed from the back of the
antenna, a fixture is required to connect a coaxial cable for measurements.  Once again care
was exercised in orienting the waveguide adapter probe in a similar fashion to those in the
LNB.  The azimuth pattern in Figure 4-18 shows grating lobes approximately 65 degrees off
boresight.  The amplitude of these grating lobes is slightly higher than the spillover lobes of
the reflectors.  The cross polarization amplitude is comparatively high.  The elevation cut in
Figure 4-19 also exhibits grating lobes.  Grating lobes usually occur when elements in an
array are separated by more than one wavelength.  The contour plot in Figure 4-20 shows the
spatial distribution of the grating lobes.
4-14
-60
-40
-20
0
20
40
0
30
120
150
180
210
240
270
300
330
Azimuth Cut Fortel Flat Panel Antenna 12.45 GHz
RHCP
LHCP
Ga
i
n
 (
d
Bic)
Grating Lobe
Grating Lobe
Figure 4-18.  Azimuth Radiation Pattern of Fortel Flat Panel Antenna
-60
-40
-20
0
20
40
0
30
60
90
120
150
180
210
240
330
Elevation Cut Fortel Flat Panel Antenna 12.45 GHz
RHCP
LHCP
Ga
i
n
 (
d
Bi
c)
Grating Lobe
Grating Lobe
Figure 4-19.  Elevation Radiation Pattern of Fortel Flat Panel Antenna
4-15
Figure 4-20.  RHCP Radiation Pattern of Fortel Flat Panel Antenna
4.2.5  Boresight Gain Summary
Table 4-1 summarizes the boresight gain for the antennas at 12.2, 12.45, and 12.7 GHz.
It should be clearly stated that the maximum small sectoral horn gain occurs off boresight.
This can be seen in Figure 4-2 where the Northpoint gain is highest about 50 degrees off
boresight.  Interestingly, the DIRECTV 24-by-18-inch single feed has very similar gain to
that of the DIRECTV 18-inch reflector.  The gain of the DIRECTV 24-by-18-inch dual feed
reflector is slightly lower that the single feed version due to the feed being located away from
the focal point of the reflector.  The measured gain values are approximately 1.0 to 1.5 dB
lower than expected based on information provided by the vendors.  For example, the
efficiency of the 18-inch reflector based on the gain shown below ranges from 49 to 55%
while the claimed efficiency is about 70%.
4-16
Table 4-1.  Boresight Gain Summary
Antenna 12.2 GHz 12.45 GHz 12.7 GHz
Small sectoral 6.7 dBil 8.4 dBil 8.8 dBil
Large sectoral 14.3 dBil 13.9 dBil 14.8 dBil
DIRECTV 18-inch
Reflector
32.2 dBic 32.4 dBic 33.0 dBic
DIRECTV 24 x 18-
inch Reflector Single
Feed
32.4 dBic 32.5 dBic 33.1 dBic
DIRECTV 24 by 18-
inch Reflector Dual
Feed
31.8 dBic 31.8 dBic 32.6 dBic
Fortel 31.9 dBic 32.4 dBic 32.9 dBic
NOTES:
dBi  = dB referenced to the gain of an isotropic antenna
dBil = dB referenced to the gain of a linearly polarized isotropic antenna
dBic = dB referenced to the gain of a circularly polarized isotropic antenna
4.3  Polarization
The effects of the polarization of the MVDDS transmitted wave and the polarization of
the DBS receive antenna must be considered.  The following sections address polarization
and its impact on received interference power.
4.3.1  The Transmitted Wave
Assume a plane wave in space is propagating along the z-axis.  Let the wave have two
components, one in the x (horizontal) direction and one in the y (vertical) direction.  The E
field of the wave can be described as:
?j
yyxx
eUEUE
rr
+ (4)
Where:
Ex = the electric field in the x (horizontal) direction
x
U
r
 = a dimensionless unit vector in the x direction
Ey = the electric field in the y (vertical) direction
4-17
y
U
r
 = a dimensionless unit vector in the y direction
? = an electrical phase angle indicating how much the vertical component leads the
horizontal component
Notes:
(1) If Ex = Ey and ? is 90 degrees, then the wave is left-hand circular polarized (LHCP).
(2) Ex has units of Volts/meter.
(3) The power flux density (PFD) for the horizontal component is:
0
?
*
xx
H
EE
PFD = (5)
Where:
Ex
*
 = the complex conjugate of Ex
?
0
 = the impedance of free space = 120?
4.3.2  Receive Antenna Response
In order to evaluate the impact of polarization, we need to consider how the receive
antenna responds to the wave described above.  Let R
x
 be the response of the antenna to the x
(horizontal) component of the E field of the incoming plane wave.  Also the response to the y
(vertical) component of the E field is:
?j
y
eR (6)
In this formulation, ? is an electrical phase angle describing how much the response to
the vertical component leads the response to the horizontal component.  R
x
 and R
y
 have units
of meters.
4.3.3  Combined TX and RX
The output of the receive antenna as it responds to the wave above would be:
)(j
yyxx
eRERES
???
+= (7)
This signal has units of Volts.  Clearly, both the wave in space and the receiving antenna
must be based on the same coordinate systems.  The power received is as follows:
0
?
*
R
SS
P = (8)
4-18
Relating these quantities to well known path loss equations, we find that:
2
0
4 d
GP
E
THT
x
?
?
= (9)
2
0
4 d
GP
E
TVT
y
?
?
= (10)
?
?
4
2
RH
x
G
R = (11)
?
?
4
2
RV
y
G
R = (12)
Where:
P
T
 = the transmitted power (Watts)
G
TH
 = the horizontal component of the gain of the transmit antenna, relative to isotropic
G
TV
 = the vertical component of the gain of the transmit antenna, relative to isotropic
G
RH
 = the horizontal component of the gain of the receive antenna, relative to isotropic
G
RV
 = the vertical component of the gain of the receive antenna, relative to isotropic
d = the distance between antennas
? = the wavelength
Let us define two new constants:
2
0
1
4 d
P
C
T
?
?
= (13)
?
?
4
2
2
=C (14)
So that:
THx
GCE
1
= (15)
TVy
GCE
1
= (16)
4-19
RHx
GCR
2
= (17)
RVy
GCR
2
= (18)
Substituting and rearranging, the received power can be rewritten as:
( )
RVRHTVTHRVTVRHTHTR
GGGG)(GGGGCPP ?? ?++= cos2
3
(19)
where:
2
3
4
?
?
?
?
?
?
=
d
C
?
?
(20)
We note that C
3
 is the well-known free space path loss factor.
4.3.4  Polarization Model
The analysis model used to evaluate the effects of interference on DBS receivers must
take into account polarization.  The polarization approach used in this model is based on
equation 16 but for simplicity, it ignores the relative phase angles.  The equation used in the
analysis model is:
()
RVTVRHTHTR
GGGGCPP +=
3
(21)
From the above relationships, we define a new quantity, the effective gain product of the two
antennas.  The true effective gain product is:
( )
RVRHTVTHRVTVRHTHtrue
GGGG?)(?GGGGGP ?++= cos2 (22)
Also, the effective gain product for the system analysis model is:
()
RVTVRHTHelmod
GGGGGP += (23)
Where:
GP
true
 = the true effective gain product of the two antennas, taking polarization into
account
GP
model
 = the model for the effective gain product of the two antennas used in the system
analysis tool
Example results are shown below.  Figure 4-21 shows the true gain product for an area
6 km x 6 km, south of a Northpoint transmitter.  The transmitter is at 100 meters height
above level terrain.  The DBS receive antenna is at terrain height.  The DBS antenna is the
18-inch dish, which is aimed at a satellite at 119 W Longitude from the Washington, DC
area.  The Northpoint transmit antenna is the large sectoral horn.  It is aimed directly south
4-20
with no up-tilt.  The contour plot shows the decibel version of the true gain product, taking
polarization into account.  Contours are in 5-dB steps.  As shown in Section 4.5.3, the actual
received interference power would be the decibel sum of the gain product shown in the
figure plus the decibel version of the transmit power less the free space loss.  Note that the
area of large gain product matches the area of most interference impact for the Washington
DC case presented in Section 5.1.
Figure 4-21.  True Gain Product
The above gain product plot should be compared to the gain product model used in the
system analysis tool.  The latter is shown in Figure 4-22 for the same scenario described
above.  As seen from the figures, the model matches true performance closely, especially in
regions where the gain product is largest.  The model used in the system analysis tool is
conservative, but only slightly conservative.
4-21
Figure 4-22.  MITRE Model for Gain Product
Other analyses have apparently used different models for the effects of polarization.  In
some of these cases, polarization is dealt with in terms of an isolation factor.  Various values
for the polarization isolation from 0 to 3 dB have been used in different analyses.  It is
assumed that in the approaches that use this technique, the dominant-mode gain is the
starting point for determining the gain product.  So, such models can be described as follows:
?
maxRmaxT
dom
GG
GP = (24)
Where:
GP
dom
 = the dominant-mode model for effective gain product of the two antennas
4-22
G
Tmax
 = the maximum gain of the transmit antenna at given azimuth and elevation angles,
considering vertical, horizontal, right hand circular, and left hand circular
polarizations
G
Rmax
 = the maximum gain of the receive antenna at given azimuth and elevation angles,
considering vertical, horizontal, right hand circular, and left hand circular
polarizations
? = the polarization isolation factor used in the dominant-mode model
Results for the dominant-mode model are shown in Figure 4-23 for a polarization
isolation factor of unity (zero dB).  These results are based on the same scenario described in
the examples above.  Here we see that the dominant-mode model using a zero-decibel
polarization isolation factor is also conservative.  However, the dominant-mode model is
more conservative than the model used in the system analysis tool.
Figure 4-23.  Dominant Mode Model for Gain Product
5-1
Section 5
Interference Assessment
5.1  Interference Predictions
The impact of interference from an MVDDS transmitter upon DBS receivers in its
vicinity is a function of several parameters:
 The interference-impact criterion (e.g., absolute or relative increase in DBS downlink
unavailability).
 The DBS-receiver performance criterion:  the receiver performance level (e.g., VQ6)
that must be met or exceeded for the DBS downlink to be considered available.
 The geographical locale under consideration (e.g., Washington, DC).  This
determines the local rainfall statistics that very strongly affect downlink availability.
 The output power of the MVDDS transmitter.
 The modulation/channelization scheme employed by the MVDDS transmitter.
 The radiation pattern of the MVDDS transmitting antenna.
 The boresight azimuth angle of the MVDDS transmitting antenna.
 The boresight elevation (tilt) angle of the MVDDS transmitting antenna.
 The radiation patterns of the DBS receiving antennas.
 The boresight azimuth and elevation angles of the DBS receiving antennas.  These
are determined by satellite longitude, and by the latitude and longitude of the locale.
 The MVDDS transmitting antennas height above average terrain.
 The assumed frequency of the DBS downlink signal.
 The offset between MVDDS and DBS carrier frequencies.
 The EIRP that each satellite directs toward the locale of interest.
In order to investigate the potential impact of MVDDS interference upon DBS, MITRE
has developed a MATLAB? application embodying the computational technique of
Section 2.1.  This model has been used to analyze a variety of cases involving various
combinations of the parameters discussed above.  Appendix B presents the resulting set of 56
contour plots, which are discussed in detail later in this section.  The plots provide a
5-2
quantitative basis for gauging the severity of the potential interference problem and for
evaluating the effectiveness of possible mitigation techniques.
One of those plots, generated for the Washington, DC benchmark case that serves as a
basis for comparison with most of the other plots, is reproduced in Figure 5-1.  The model
has computed the absolute increase ?U caused by MVDDS in the rain-induced unavailability
U, where U and ?U are both measured in hours per year (hr/yr), of the downlink from each
of three satellites to postulated DBS receivers at each of 32,761 gridpoints on the plot.
Contours have been drawn to connect points at which the maximum unavailability (the worst
of the three single-satellite values computed for each gridpoint) is equal to certain selected
values such as 0.3 hr/yr.  The plots are discussed further in 5.1.2 below.
5.1.1  Ranges of Parametric Values Used in the Simulations
Four different interference-impact criteria were applied in the simulations:
 The maximum absolute unavailability increase, obtained by taking the largest value
of ?U experienced by any of the three satellite downlinks at the gridpoint under
consideration, as explained above.  This criterion was used in the benchmark
simulation and in all but three of the other simulations done for this study.  In each
such simulation, contours were plotted for each of five values of ?U:  0.3, 1, 3, 10,
and 30 hours per year.
 The maximum relative unavailability increase (?U/U
0
), where U
0
 is the baseline
value of U that exists for a given satellite in the locale under consideration even when
MVDDS is not present.  This criterion was employed in one variation of the
benchmark simulation, with contour values set at 2.86%, 10%, 30%, 100%, and
300%.
 The maximum total unavailability (U
0
 + ?U) due to rain and MVDDS combined.
This criterion was used only in one benchmark variation, with contour values set at
25, 30, 35, 40, and 45 hr/yr.
 The minimum clear-air value of (C/I
M
), where C is the weakest DBS downlink power
level and I
M
 is the MVDDS-interference power level, at the output of a DBS
receiving antenna placed at the gridpoint in question.  In the single simulation in
which this criterion was used, the model was set to generate contours for 5, 10, 15,
20, and 25 dB.
Three different DBS-receiver performance criteria were employed:  VQ6 (which was
used in the vast majority of the simulations), QEF, and VQ1.
Ten different locales were considered at least once in the simulations: Washington, DC;
Miami, FL; Phoenix, AZ; Boston, MA; Chicago, IL; Houston, TX; Los Angeles, CA;
Denver, CO; Seattle, WA; and Fargo, ND.
5-3
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
Figure 5-1.  Interference Impact Predictions for Benchmark Case
1.0
  0.3 hr/yr
MVDDS
coverage
boundary
North
?
5-4
These values of MVDDS transmitter output power were used in the simulations: -10, 4,
1.5, 0, 10, 20, and 30 dBm, with 0 dBm the value most often used.  (These are raw
transmitter output power values, not EIRPs.  The MVDDS EIRPs are 10 or 14 dB higher
than the raw powers, depending on the type of transmitting antenna employed.)
All the simulations assumed an MVDDS modulation/channelization scheme identical to
that of DBS.  Alternative schemes could conceivably be implemented, but insufficient
information exists on such schemes to provide an adequate basis for predicting their
interference impacts.
The measured radiation patterns of four different kinds of MVDDS transmitting antennas
were used in the simulations:  the large and small sectoral horns of Northpoint and Pegasus,
respectively.
Several MVDDS boresight azimuth angles were considered in the simulations.  The most
commonly used was 180 (due south).  Also modeled were 135 (southeast), 225
(southwest), 090 (east), 270 (west), and 000 (north).
Two MVDDS elevation tilt angles were considered:  0 (used in all but one of the
simulations) and 5.
The radiation patterns of three different types of DBS receiving antennas were used:  the
18 dish, the 24 x 18 single-feed reflector, and the 24 x 18 dual-feed reflector.
Thirty different combinations of DBS-receiver boresight azimuth and elevation angles
were usedone for each of the three DBS satellite longitudes at each of the ten locales
studied.
The following values of MVDDS antenna height (above the horizontal plane containing
all the gridpoints) were considered:  50, 0, 50, 100 (the most commonly used value), 200,
300, and 400 meters.
Simulations were performed for three different assumed values of DBS downlink
frequency:  12.20 GHz (the low end of the band), 12.45 GHz (the center frequency and the
one most commonly assumed in the simulations), and 12.70 GHz.
Two values of MVDDS-DBS carrier offset were considered:  0 MHz (the value most
often used) and 7 MHz.
Satellite EIRP depends on the satellite longitude of interest (101 W, 110 W, or 119 W)
and the specific satellite and transponder under consideration.  It also depends on the locale
under consideration, because the shaped beams of the satellite transmitting antennas direct
substantially different EIRPs toward different parts of the United States, as explained in
(Barker, 14 March 2001).  In most of our simulations we have assumed, for each of the three
satellite longitudes, the satellite and transponder that produce the minimum ratio of satellite
EIRP to receiver interference threshold that is possible for the locale of interest.  The receiver
5-5
interference threshold is the minimum value of C/(N+I) that allows the DBS receiver to meet
the specified performance criterion, usually VQ6.  The threshold is a function not only of the
criterion but also of the code rate, which in turn depends on the DBS vendorDIRECTV or
EchoStarto which the satellite belongs.
Minimizing the EIRP-to-threshold ratio allows the analysis to focus on the satellites with
the tightest link budgets, and thus presumably the greatest susceptibility to MVDDS
interference, in each locale studied.  However, the minimum ratios were not used in the
Phoenix or Los Angeles simulations for the 119 W satellite longitude, since those result in
unacceptably weak downlinks with rain-induced unavailabilities of 323.46 and 177.67 hr/yr,
respectively, even with MVDDS absent.  Also, in one simulation, for comparison purposes
we assumed maximum values for this ratio, to see how the strongest downlinks would fare in
the presence of MVDDS interference.  Table 5-1 shows the EIRP-to-threshold values and the
associated baseline unavailabilities (without MVDDS) used in our VQ6 simulations.
(Other values were assumed in our QEF and VQ1 simulations.)
Table 5-1.  EIRP-to-Threshold Ratios (dBW) and Unavailabilities for VQ6
Satellite Longitude
101W 110W 119W
Locale
Ven-
dor
a
Ratio
(dBW)
U
0
(hr/yr)
Ven-
dor
a
Ratio
(dBW)
U
0
(hr/yr)
Ven-
dor
a
Ratio
(dBW)
U
0
(hr/yr)
Washington, DC (min. ratio) D 47.7 2.17 E 46.5   3.88 D 43.3 24.56
Washington, DC (max. ratio) D 48.0 1.95 D 47.7   2.62 E 49.6   1.73
Miami, FL (min. ratio) D 48.1 8.10 E 46.0 17.46 D 43.6 57.91
Phoenix, AZ (min. ratio) D 45.7 2.66 E 42.3 16.37  E
b
  42.1
b
 19.02
b
Boston, MA (min. ratio) D 46.2 2.92 E 45.5   4.77 D 42.4 44.63
Chicago, IL (min. ratio) D 46.0 2.89 E 46.0   3.07 D 42.3 31.33
Houston, TX (min. ratio) D 48.2 4.48 E 45.5 11.65 D 43.3 36.55
Los Angeles, CA (min. ratio) D 45.5 1.42 E 41.9 11.69  E
b
  42.1
b
   9.29
b
Denver, CO (min. ratio) D 44.7 0.79 E 43.0   2.22 D 40.8 33.25
Seattle, WA (min. ratio) D 44.0 6.84 E 41.8 28.79 D 41.3 55.87
Fargo, ND (min. ratio) D 44.2 4.78 E 42.5 14.26 D 41.3 63.24
NOTES:
a. D = DIRECTV; E = EchoStar.
b. The second-smallest ratios (and their associated vendors and baseline unavailabilities) are shown for the
119 W satellite longitude for Phoenix, AZ and Los Angeles, CA.
c. Actual EIRP values fluctuate between 0 and 0.8 dB off peak, so we consistently subtracted 0.4 dB from
the peak values of EIRP provided in (Barker, 14 March 2001).
d. The VQ6 receiver threshold values used in creating this table are 5.5 dB for EchoStar and 7.3 dB for
DIRECTV, as explained in Section 3 of the report.  To determine the satellite EIRP in dBW used for
each case, add the appropriate value to the ratio shown in the table.
5-6
5.1.2  Discussion of Results
Appendix B contains 56 plots showing contours of constant predicted interference impact
upon populations of postulated DBS receivers dispersed across horizontal planes in the
vicinity of an MVDDS transmitter located at the origin.  Free-space path losses are assumed
for the MVDDS signal out to the 4/3-earth radio horizon, beyond which infinite signal
attenuation is assumed.  The radio horizon is located 4.126
MD
H?  km from the MVDDS
transmitter, where ?H
MD
 is the amount in meters by which that transmitter is assumed to lie
above the horizontal plane being studied in a given simulation.  (However, the radio horizon
is ignored in the few simulations where ?H
MD
 is zero or negativei.e., where the MVDDS
transmitter is assumed to lie in or below the horizontal plane of interest.)  Color codes for the
plots are discussed on pages B-1 and B-2.
The contour plot on page B-3 duplicates Figure 5-1.  It addresses the benchmark case,
in which the locale is Washington, DC, and the frequency of interest is 12.45 GHz.  The
MVDDS transmitter has no frequency offset, and emits a 0-dBm signal.  Its antenna is a
south-pointing Northpoint large sectoral horn, with no elevation tilt, 100 meters above the
horizontal plane.  The DBS receivers lying within that plane use 18 dish antennas and have
a VQ6 performance criterion.  The minimum possible EIRP-to-threshold ratio is assumed for
each of the three satellite longitudes.  The impact criterion is the maximum absolute
unavailability increase.  The contour associated with the smallest unavailability increase
considered (0.3 hr/yr) extends about 6.5 km south of the transmitter, while the 1.0- and 3.0-
hr/yr contours enclose considerably smaller areas.
The assumption of free-space path loss out to the radio horizon in this and the other plots
means that natural shielding by terrain, foliage, and buildings is not being taken into
account.  This omission, necessitated by the lack of adequate data for predicting such
shielding, undoubtedly exaggerates the sizes of the interference contours shown on the plots.
If natural shielding were considered, those contours would certainly enclose smaller areas.
However, the same is probably even more true of the MVDDS service boundaries.  Natural
shielding has the greatest effect when signals arrive at low elevation angles, as the desired
MVDDS signals will nearly always be doing at the outskirts of their nominal service areas.
It is important to keep in mind that the real-world advantages and disadvantages of
natural shielding are partially offset by reflection, scattering, and diffraction effects that also
are not modeled here.  These tend to illuminate the shadows cast by obstacles and reduce
the degree of shielding in many cases.
Another simplifying assumption used in our analysis has been to disregard rain
attenuation of the MVDDS signal.  Had it been feasible to consider this factor, the
interference contours would probably have shrunk furtherbut, again, so would the
MVDDS coverage boundaries (during rain).
5-7
Our implicit assumption that only one MVDDS transmitter is involved represents yet
another analytical simplification.  Although multiple transmitters are likely to coexist in a
given locale, in all but very limited regions a single transmitter will be the predominant
source of interference to any single DBS receiver pointed toward a particular satellite.  The
reason is the strong dependence of received MVDDS signal strength on path distance and on
the gain function of the DBS receiving antenna in the direction of the arriving signal.  These
effects will typically cause differences well in excess of 10 dB between the strongest
MVDDS signal and the runner-up.  Cases where the cumulative effect of additional MVDDS
transmitters would exceed that of the predominant transmitter are expected to be relatively
unusual and are not modeled here.
All the remaining plots represent excursions from the benchmark case, in which one,
two, three, or four parameters are varied from their benchmark values to determine the
sensitivity of the results to such variations.  The legend beneath each such plot highlights in
bold type the parametric changes that distinguish the scenario in question from the
benchmark scenario.
Pages B-4, B-5, and B-6 revisit the benchmark case, except that they show separate
unavailability results for each of the three satellite longitudes:  101 W, 110 W, and 119 W.
Even though, as usual, the weakest downlink (the one with the smallest possible EIRP-to-
threshold ratio) is being considered for each longitude, it is evident that for the 101 W
satellite the unavailability increase is less than 0.3 hr/yr everywhere in the region studied.
For 110 W the increase exceeds 0.3 hr/yr only within a region much smaller than a square
kilometer.  For 119 W the results are almost identical to those for the multisatellite result of
page B-3, because the downlink from that satellite longitude is much weaker (in relation to
the DBS receivers interference threshold) than those arriving from the other longitudes.
Consequently, its unavailability exceeds that of the other downlinks virtually everywhere in
the region studied, completely overshadowing the contributions of the two other downlinks
to the worst-case unavailability values depicted in the composite multisatellite benchmark
plot of page B-3.
All plots after page B-6 show composite multisatellite results, in the manner of the initial
benchmark plot of page B-3.  The plot on page B-7 depicts in detail the one-square-kilometer
region behind (north of) the south-pointing MVDDS transmitting antenna.  Here the
MVDDS coverage boundary is very complex, and the interference-impact regions are quite
small but very intense, rising steeply to values above 30 hr/yr in the three hot spots that
exist in the parts of the horizontal plane where DBS receivers pointing at the three satellites
will also have to point very close to the source of MVDDS interference.
The plots of pages B-8 through B-10 evaluate the benchmark scenario in the light of
alternative interference-impact criteria.  On page B-8, the criterion is the maximum relative
unavailability increase, expressed as a percentage of baseline unavailability; on page B-9, it
is the maximum total unavailability increase; and on page B-10 it is the minimum clear-air
5-8
(C/I
M
) value.  Note that the relative-increase and total-unavailability numbers are based on
the simplifying assumption that rain and MVDDS are the only causes of unavailability.  If
solar unavailability and other items in the unavailability budget were considered, the baseline
unavailability would be larger and the relative increase due to MVDDS would shrink
accordingly.
Pages B-11 and B-12 display the effects of increasing the MVDDS antenna height.
When this rises to 200 meters (B-11), the maximum-absolute-unavailability-increase
contours shrink noticeablya shrinkage that becomes dramatic when the height increases to
400 meters (B-12).  The shrinkage results from the relatively high vertical directivity of the
MVDDS sectoral horn antenna.  (The same vertical directivity also produces a much smaller
but still noticeable shrinkage in the MVDDS coverage boundary as the antenna height
increases.)
On the other hand, pages B-13 through B-15 show that reducing the antenna height
below 100 meters has relatively little effect on the interference impact.  The interference
contours for heights of 50 meters (B-13), 0 meters (B-14), and 50 meters (B-15) all look
quite similar to those obtained for 100 meters in the benchmark case.  Of course, natural
shielding would undoubtedly reduce the interference regions (as well as the MVDDS
coverage area) if such obstructions were considered in our model.  The results at low heights,
especially when ?H
MD
 is zero or negative, are useful mainly for quantifying the possible
effects of MVDDS interference on DBS receivers that might happen to be located on
hillsides rising above the level of an MVDDS transmitter.
Page B-16 shows the effect of a 5 upward elevation tilt in the MVDDS antenna.  The tilt
directs the antennas main beam away from the horizontal plane and obviously reduces the
size of the interference contours, although a substantial reduction in MVDDS coverage area
also occurs.
In the simulation of page B-17, a 7-MHz frequency offset is postulated between the
MVDDS and DBS carriers.  The resultant 1.7 dB of interference protection, documented in
Section 3, substantially shrinks the interference contours while leaving the MVDDS
coverage boundary unchanged.
Page B-18 shows the effect of using the Northpoint small sectoral horn instead of the
large one.  The effects are reminiscent of those produced earlier when large horn was tilted
5 upward:  shrinkage of the interference region, but with a concomitant reduction in
MVDDS coverage to the south.  The slightly squashed radiation pattern of the small horn
antenna actually provides slightly better coverage to the sides than directly in front of the
antenna.
Pages B-19 through B-25 depict the effects of changes in the azimuth angle of the
MVDDS transmitting antenna in the Washington, DC area.  When a Northpoint large
sectoral horn antenna is pointed to the southeast (B-19), the interference contours are smaller
5-9
than for the south-pointing benchmark case, but a southwestern orientation (B-20) makes the
situation worse.  An eastern orientation (B-21) helps substantially, but not a western one
(B-22).  Contrary to widespread expectation, pointing the antenna north (B-23) seems to
work quite well, undoubtedly by ensuring that the butterfly backlobes of the DBS
receiving antenna will not be illuminated by the Northpoint main beam.  The plots of pages
B-24 and B-25 explore this scenario further.  On page B-24 is a detail of the region in front
(i.e., north) of the north-pointing MVDDS transmitter, with hot spots that are largerand
undoubtedly also more intensethan the ones in the detail of page B-7 for the south-pointing
case.  Page B-25, reverting to the usual scale, shows the region behind (south of) the north-
pointing transmitter.
Page B-26 shows what happens when the maximum EIRP-to-threshold ratio (rather than
the minimum) is assumed for each satellite longitude.  In this case the interference contours
virtually disappear from the map, because here the simulation is addressing the strongest
downlinks, which are best able to resist MVDDS interference.
The plot of page B-27 depicts the effect of ignoring the 1-dB interference-scaling factor
used in nearly all the other simulations.  It is assumed here that MVDDS interference has
exactly the same disruptive effect as Gaussian noise.  This changed assumption produces a
significant but not particularly dramatic enlargement of the interference contours.
Pages B-28 and B-29 show interference contours for two alternative DBS-receiver
performance criteria:  QEF (B-28), which greatly enlarges the regions of apparent
interference impact; and VQ1 (B-29), which dramatically shrinks them.
Pages B-30 and B-31 depict the effects of alternative DBS receiving antennas.  The
24x18 single-feed antenna (B-30) greatly reduces the interference regions, presumably by
eliminating the butterfly backlobes.  The 24x18 dual-feed antenna (B-31) seems somewhat
less effective in controlling interference.
Two plots consider the frequencies at the low and high ends of the band:  12.20 GHz
(B-32) and 12.70 GHz (B-33).  The interference regions seem smaller in the latter plot.
Variations in the MVDDS output power are explored in the plots of pages B-34 through
B-41.  Unsurprisingly, as the power increases the interference contours expand (and so does
the MVDDS coverage boundary, although the radio horizon limits this effect unless the
MVDDS antenna height is increased along with the power.)
In the next fourteen plots, nine alternative locales are considered.  DBS receivers in those
locales all seem more susceptible to MVDDS interference than they are in Washington, DC,
at least in the scenarios considered.  In Miami, FL (B-42), the area encompassed by the 0.3-
hr/yr contour seems to be well over twice as large as in the benchmark Washington, DC
scenario.  Much the same is true of Phoenix, AZ (B-43).  (Page B-44 shows another Phoenix
plot where the interference-scaling factor has been ignored, as it was on page B-27, with
5-10
similar results.)  The interference contours are also relatively large in Boston, MA (B-45),
Chicago, IL (B-46), and Houston, TX (B-47).  (The prominent spike in the Houston plot
appears to result from a similar spike that exists in the backlobe region of the DBS 18
receiving antenna.)  Los Angeles (B-48) seems to have the smallest interference contours of
any locale studied except for Washington, DC.
Potential MVDDS-to-DBS interference problems seem relatively severe in Denver, CO,
Seattle, WA, and Fargo, ND.  However, mitigation techniques are available and were
simulated for Denver and Seattle.  The serious problems indicated in the first Denver plot
(B-49) were greatly mitigated when the MVDDS antenna was turned northward and a
7-MHz frequency offset was used (B-50).  Even greater improvements were obtained for
Denver when these expedients were supplemented by raising the MVDDS antenna 300
meters above the plane of interest.  The same measures yielded similar improvements in the
Seattle simulations of pages B-52 through B-54, although the improvements there were not
as dramatic as for Denver.  This is partly because the problem in Seattle was smaller to begin
with, but a more important reason may be that satellite elevation angles are lower in Seattle
than in Denver.  This decreases the angular separation between the DBS receiving antennas
main beams and the horizontal plane containing the MVDDS main beam, thereby tending to
increase the gain product and thus the amount of MVDDS interference coupled into the DBS
receiver.  The results for Fargo appear on page B-55; mitigation techniques were not tried for
that locale.
All the simulations discussed above assumed the use of Northpoint antennas.  The final
three simulations employed Pegasus antenna patterns instead.  Pegasus did not provide its
actual antennas to MITRE for testing, so MITRE had to rely on a limited set of previously
measured data supplied by Pegasus in modeling the radiation patterns of the Pegasus
antennas.  Of the patterns supplied by Pegasus, the only ones usable in these simulations
were azimuthal-plane cuts, so our Pegasus simulations had to be confined to cases where the
MVDDS antenna lies within the horizontal plane of interest (not above or below it) and the
elevation tilt angle is zero.  Page B-56 displays the results obtained under these conditions
for the Pegasus large sectoral horn; the interference contours appear similar to those obtained
under the same conditions for the Northpoint antenna and depicted on page B-14.  Page B-57
shows results for the Pegasus small sectoral horn; the interference contours are larger than
for its Northpoint counterpart  (B-18) and the associated MVDDS coverage boundary has a
rounder shape.
A Pegasus consultant has claimed (Telecommunications Systems, 2001) that Pegasus can
increase the G/T of its own receivers 4 dB, to 15.2 dB/K, through the use of measures
including the use of 67-cm receiving antennas.  If Pegasus does this and then reduces its
transmitter power by the same 4 dB (to 4 dBm), thus keeping its coverage boundary
constant while reducing its interference contours, the results will look as shown on page
B-58 if the Pegasus large sectoral horn is used.  It must be noted that Northpoint or any other
5-11
MVDDS vendor could obtain equivalent results by using the same measures (including
larger receiving antennas) to increase G/T.
5.2  Criteria for Sharing
The analysis provided in previous sections provides insight into the potential extent of
possible interference from MVDDS transmitters.  The analysis and results shown above
describe how bad interference might be.  However, it is important to recognize that the
results given are representative only.  In any given MVDDS deployment many factors are
available to the system designer and these factors may be used to reduce the real impact of
potential interference.  In light of this, the FCC may decide to impose certain criteria for the
deployment of an MVDDS system.  The goal of this section is to suggest some possible
criteria that might be used by the FCC for this purpose.
Section 5.2.1 provides a list of some possible types of criteria.  From these, two are
selected for discussion in more detail.  Section 5.2.2 presents criteria in terms of C/I ratios.
Quantitative results are provided for a wide range of impacts on DBS unavailability.  If the
FCC chooses to impose criteria, these results will be an aid to determine a specific
quantitative set of values for these criteria.  Section 5.2.3 presents similar results in terms of
interference levels at the DBS receiver.  Again quantitative results are given as an aid to the
FCC for selection of specific criteria.
5.2.1  Possible Sharing Criteria
Many different criteria are possible for the protection of DBS receivers in the presence of
MVDDS transmitters.  In general these limit either the computed unavailability or the
interference power.  Some possible criteria are as follows:
1. Maximum total unavailability
2. Maximum increase in unavailability
3. Maximum relative increase in unavailability (in percent)
4. Minimum C/I
5. Maximum interference power at the DBS LNB
6. Maximum power flux density (PFD)
7. Maximum power or EIRP
The exact wording of a given criterion would depend on a number of policy issues.
Some of these issues are discussed in Section 6.1.  However, an example criterion might
limit one of the quantities above for any possible DBS receiver location in areas zoned
residential or industrial.  Criteria would also need to take into account the envelope of
possible DBS antenna patterns and the various DBS satellites that are in view.  Clearly many
5-12
things affect each parameter above and the FCC would need to decide which to hold constant
and which might be allowed to vary.  For example, a limit on total unavailability might vary
by city, but a particular DBS antenna envelope might be used in all cases.
The following Sections discuss two of the above criteria in detail.
5.2.2  Minimum C/I Criteria
Recall that the long-term (i.e., in an average year) DBS basic service outage caused by
rain depends on the rainfall rate at the geographic location under consideration.  As the
MVDDS is introduced into the operating environment, the effective noise floor of the DBS
system is increased.  The compatibility of the MVDDS with the DBS system can be
described in terms of three critical parameters as mentioned in Section 2.1, namely:
 Vthe percentage increase of the unavailability of the DBS service from its basic
service outage rate p
Rm
.
 ?Uthe increase in time of the DBS service unavailability from its basic service
outage time U
0
.
 P
total
the total percentage of time in an average year that the DBS service is
unavailable (due to rain plus MVDDS).
The geographic dependence of these parameters at selected U.S. cities has been
investigated and discussed in Section 5.1.  Note that each of these parameters can be
expressed, either explicitly or implicitly, as a function of the received rainy-sky carrier-to-
MVDDS interference power ratio [CI
MV
]
rainy-sky
 which is related to the clear-sky C/I, [CI
MV
]
0
,
through the effective rain margin A
eRm
 as discussed in Section 2.1, i.e.,
[CI
MV
]
0
 = [CI
MV
]
rainy-sky
 + A
eRm
where all quantities are measured in dB.
Based on the results presented in Section 5.1 for the worst case satellite (longitude
119 W) scenario, Figure 5-2 illustrates the relationship between V and [CI
MV
]
0
 at ten
selected U.S. cities.
(a):  Boston, MA
(b):  Chicago, IL
(c):  Denver, CO
(d):  Fargo, ND
(e):  Houston, TX
(f):  Los Angeles, CA
5-13
(g):  Miami, FL
(h):  Phoenix, AZ
(i):  Seattle, WA
(j):  Washington, DC
V (%)
[C/I
MV
]
0    
(dB)
ac
10 15 20 25 30 35
1
10
100
1
.
10
3
o s
i
n
r
o u
s
ia
h e
a
CIbos CIchi, CIden, CIfar, CIhou, CIlos, CImia, CIphe, CIsea, CIdc,
1000
a
b
c
d
e
f
g
h
i
j
Figure 5-2.  Percentage of Increase of Unavailability for DBS System
5-14
Figure 5-3 shows ?U, in hours per year, at these sites as a function of [CI
MV
]
0
.
[C/I
MV
]
0
   (dB)
?U (hr/yr)
10 15 20 25 30 35
0.1
1
10
100
1
.
10
3
b os
chi
d en
far
h ou
los
mia
p he
s ea
d c
CIbos CIchi, CIden, CIfar, CIhou, CIlos, CImia, CIphe, CIsea, CIdc,
a
00
b
c
d
e
f
g
h
i
j
a
Figure 5-3.  Increase in Time of Unavailability for DBS System
5-15
The resulting total unavailability probability of the DBS system (due to the effects of rain
and MVDDS) is depicted in Figure 5-4.
P
total 
(%)
10 15 20 25 30 35
0.1
1
10
pbos
pchi
pden
pfar
phou
plos
pmia
pphe
psea
pdc
CIbos CIchi, CIden, CIfar, CIhou, CIlos, CImia, CIphe, CIsea, CIdc,
a
[C/I
MV
]
0    
(dB)
b
c
d
e
f
g
h
i
j
a
Figure 5-4.  Total Percentage of Time of Unavailability in an Average Year for
DBS System
The figures are developed to facilitate the FCC policy decision makers to formulate the
overall criteria, and /or specific requirements at an individual locale, in terms of these
parameters.  Once the maximum acceptable value of a given parameter is decided, the
required minimum value of [CI
MV
]
0
 can be established to meet the specification.  For
example, the minimum [CI
MV
]
0
  associated with the requirement that the MVDDS should
cause no more than 10 % increase in the DBS system unavailability time can be determined
from Figure 5-2 for different locales and the results are listed in Table 5-2.
5-16
Table 5-2.  Example of Minimum [CI
MV
]
0
 to Satisfy the Requirement V? 10 (%)
Location Minimum [CI
MV
]
0
(dB)
Boston, MA 23.8
Chicago, IL 23.7
Denver, CO 27.3
Fargo, ND 25.7
Houston TX 22.4
Los Angeles, CA 22.1
Miami, FL 21.9
Phoenix, AZ 21.6
Seattle, WA 25.5
Washington, D.C. 22.9
Similarly, Figures 5-3 and 5-4 can be used to establish the minimum [CI
MV
]
0
 when
dealing with the respective requirement categories.
5.2.3  Maximum Interference Level Criteria
Another possible set of criteria could be based on limiting the interference power level at
the input to the LNB of the DBS receive antenna.  Criteria would be of the form
maxactual
II ? (25)
The actual interference power, I
actual
, would need to be computed for each MVDDS
transmitter and for each possible location of a DBS receiver.  Clearly the left side of the
expression will vary dramatically as a function of the location near the MVDSS transmitter.
In fact, plots of these values will depend on the DBS receive antenna pattern and will bear a
resemblance to the figures discussed in Section 5.1.  The right side of the expression above
forms the limiting value that must be met.  If the FCC chooses criteria of this type, the value
for I
max
 would be specified.  This value might vary by city because of differences in rain
statistics and available DBS satellite EIRP.
It would be helpful to establish a relationship between the interference power level and
various measures of unavailability.  This can be done as follows.  We recall the following
equation from Section 3.4:
5-17
)A(N)/I(
)A(C
+
?

?
0
(26)
Where:
?
0
= the threshold C/N value for noise
C(A) = the received carrier power, as a function of the rain attenuation ratio, A
A = the rain attenuation ratio
I = the interference power
N(A) = the noise power, as a function of the rain attenuation, A
 = a factor that accounts for reduced susceptibility to MVDDS
All quantities are power levels or dimensionless power ratios.  Now, the received carrier
power is equal to the clear sky signal level divided by the rain attenuation ratio.  Also, the
noise is actually made up of thermal noise and other interference terms.  These other terms
account for adjacent satellite interference, uplink noise, and cross-polarization interference.
Any downlink rain attenuates all these other types of interference.  Further, the thermal noise
is also affected by downlink rain.  So, the N(A) term above can be expanded as follows:
A
S
A
N
N)A(N
?
+?=
2
1
(27)
Where:
?
1  
= the noise power of the system when rain attenuation is very large
?
1   
- ?
2
 = the noise power of the system with no rain attenuation
?
2
 = the difference between the noise power with large rain attenuation and the noise
power with no rain attenuation
S = the clear sky signal level
? = the C/N value for other types of interference
Substituting into equation 1 and remembering that the carrier is attenuated by noise, we get:
)A/S()A/N(N)I(
)A/S(
?
?
+?+
?
21
0
(28)
This can be rearranged to solve for the rain attenuation ratio, A, as follows:
5-18
)/I(N
)]/()/[(SN
A

??
+
?+
?
1
02
11
(29)
So, for a given interference level, I, the rain attenuation must be less than the value given
above for the link to work.  From the rain attenuation, A, the link unavailability can be
computed.  (In the figures below, unavailabilities greater then 5% have been interpolated
between the 5% point and 100% at the 0 dB rain loss point.)  This unavailability can be
compared to the value that results from setting I = 0 in the equation above.
To illustrate this approach, we provide several examples.  These are shown for several
cities with 8 different satellites.  Figure 5-5 shows the total unavailability, in percent, as a
function of interference power level for Washington DC.  Results are shown for eight
different satellites with a range of EIRP and threshold values.  Otherwise, the scenario is
approximately the same as for the baseline case in Section 5.1.  Results shown are for a
threshold based on video quality 6.
Washington, DC
0.01
0.1
1
10
-125 -120 -115 -110 -105 -100 -95 -90
Interference Power (dBm)
Total Unavailability (%)
7A-L
8-L
3/6-L
5-L
1R-H
2-H
1M-H
3/6-H
Satellite
Figure 5-5.  Total Unavailability for Washington, DC
5-19
In the figure, the prefix indicates the satellite and the suffix for each case indicates
whether the satellite uses a high EIRP value or a low EIRP.  The location of satellites is
summarized in Table 5-3.
Table 5-3.  Satellite Summary
Satellite Location System
USABSS-7A 119 W DIRECTV
USABSS-8 61.5 W EchoStar
USABSS-3, USABSS-6 119 W EchoStar
USABSS-5 110 W EchoStar
USABSS-1R 101 W DIRECTV
USABSS-2 101 W DIRECTV
USABSS-1M 110 W DIRECTV
The results shown above can also be presented in terms of the hours of outage per year.
These results are shown in Figure 5-6.
5-20
Washington, DC
1
10
100
1000
-125 -120 -115 -110 -105 -100 -95 -90
Interference Power (dBm)
Total Unavailability (hours)
7A-L
8-L
3/6-L
5-L
1R-H
2-H
1M-H
3/6-H
Satellite
Figure 5-6.  Total Unavailability in Hours for Washington, DC
From the results above, the increase in unavailability can also be computed.  This is
shown in Figure 5-7 in terms of the increase in the number of hours of outage.
5-21
Washington, DC
0.1
1
10
100
-125 -120 -115 -110 -105 -100 -95 -90
Interference Power (dBm)
Unavailability Increase (hours)
7A-L
8-L
3/6-L
5-L
1R-H
2-H
1M-H
3/6-H
Satellite
Figure 5-7.  Increase in Unavailability
The relative increase in unavailability can also be computed.  This is shown as a
percentage of the baseline unavailability in Figure 5-8.
5-22
Washington, DC
1
10
100
1000
-125 -120 -115 -110 -105 -100 -95 -90
Interference Power (dBm)
Relative Increase in Unavailablity (%)
7A-L
8-L
3/6-L
5-L
1R-H
2-H
1M-H
3/6-H
Satellite
Figure 5-8.  Relative Increase in Unavailability
As another example Figure 5-9, Figure 5-10, Figure 5-11, and Figure 5-12 show the
impact of various levels of interference for Fargo, ND.  For this scenario, the USABSS-8
satellite at 61.5 West longitude does not provide enough power to support the link, even with
no interference.
5-23
Fargo, ND
0.01
0.1
1
10
-125 -120 -115 -110 -105 -100 -95 -90
Interference Power (dBm)
Total Unavailability (%)
7A-L
3/6-L
5-L
1R-H
2-H
1M-H
3/6-H
Satellite
Figure 5-9.  Total Unavailability, Fargo
5-24
Fargo, ND
1
10
100
1000
-125 -120 -115 -110 -105 -100 -95 -90
Interference Power (dBm)
Total Unavailability (hours)
7A-L
3/6-L
5-L
1R-H
2-H
1M-H
3/6-H
Satellite
Figure 5-10.  Unavailability in Hours, Fargo
5-25
Fargo, ND
0.1
1
10
100
-125 -120 -115 -110 -105 -100 -95 -90
Interference Power (dBm)
Unavailability Increase (hours)
7A-L
3/6-L
5-L
1R-H
2-H
1M-H
3/6-H
Satellite
Figure 5-11.  Unavailability Increase, Fargo
5-26
Fargo, ND
1
10
100
1000
-125 -120 -115 -110 -105 -100 -95 -90
Interference Power (dBm)
Relative Increase in Unavailablity (%)
7A-L
3/6-L
5-L
1R-H
2-H
1M-H
3/6-H
Satellite
Figure 5-12.  Relative Increase in Unavailability, Fargo
5-27
The following figures show the impact of interference for the city of Miami.  Again the
various measures of unavailability degradation are plotted as a function of the interference
power level, in dBm.
Miami, FL
0.01
0.1
1
10
-125 -120 -115 -110 -105 -100 -95 -90
Interference Power (dBm)
Total Unavailability (%)
7A-L
8-L
3/6-L
5-L
1R-H
2-H
1M-H
3/6-H
Satellite
Figure 5-13.  Unavailability (%) for Miami, FL
5-28
Miami, FL
1
10
100
1000
-125 -120 -115 -110 -105 -100 -95 -90
Interference Power (dBm)
Total Unavailability (hours)
7A-L
8-L
3/6-L
5-L
1R-H
2-H
1M-H
3/6-H
Satellite
Figure 5-14.  Unavailability (Hours) for Miami, FL
5-29
Miami, FL
0.1
1
10
100
-125 -120 -115 -110 -105 -100 -95 -90
Interference Power (dBm)
Unavailability Increase (hours)
7A-L
8-L
3/6-L
5-L
1R-H
2-H
1M-H
3/6-H
Satellite
Figure 5-15.  Increase in Unavailability (Hours) for Miami, FL
5-30
Miami, FL
1
10
100
1000
-125 -120 -115 -110 -105 -100 -95 -90
Interference Power (dBm)
Relative Increase in Unavailablity (%)
7A-L
8-L
3/6-L
5-L
1R-H
2-H
1M-H
3/6-H
Satellite
Figure 5-16.  Relative Increase in Unavailability (%) for Miami, FL
5-31
The following figures present the impact of interference based on QEF video
performance.  These results are shown for the city of Washington, DC.
Washington, DC
0.01
0.1
1
10
-125 -120 -115 -110 -105 -100 -95 -90
Interference Power (dBm)
Total Unavailability (%)
7A-L
8-L
3/6-L
5-L
1R-H
2-H
1M-H
3/6-H
Satellite
Figure 5-17.  Total Unavailability (%) for QEF in Washington, DC
5-32
Washington, DC
1
10
100
1000
-125 -120 -115 -110 -105 -100 -95 -90
Interference Power (dBm)
Total Unavailability (hours)
7A-L
8-L
3/6-L
5-L
1R-H
2-H
1M-H
3/6-H
Satellite
Figure 5-18.  Total Unavailability (Hours) for QEF in Washington, DC
5-33
Washington, DC
0.1
1
10
100
-125 -120 -115 -110 -105 -100 -95 -90
Interference Power (dBm)
Unavailability Increase (hours)
7A-L
8-L
3/6-L
5-L
1R-H
2-H
1M-H
3/6-H
Satellite
Figure 5-19.  Unavailability Increase (Hours) for QEF in Washington, DC
5-34
Washington, DC
1
10
100
1000
-125 -120 -115 -110 -105 -100 -95 -90
Interference Power (dBm)
Relative Increase in Unavailablity (%)
7A-L
8-L
3/6-L
5-L
1R-H
2-H
1M-H
3/6-H
Satellite
Figure 5-20.  Relative Increase in Unavailability (%) for QEF in Washington, DC
Several observations can be made about the plots shown above.  First, it is clear that the
baseline unavailability varies dramatically depending on which satellite is used.  These
baseline unavailabilities without MVDDS interference can be seen by looking at the left end
of, for example, Figure 5-9.  For some satellites, the baseline unavailability is significantly
worse than the desired value of 0.3%.  Of course, we would expect changes in these baseline
unavailabilities for different rain statistics, variations in DBS antenna gain, the video quality
assumed, and a number of other parameters.
Also, we note that considering the relative increase in unavailability (measured in %)
reduces some of the variability that exist for other measures of interference outage time.  See,
for example, Figure 5-6 as compared to Figure 5-9.  This reduction in variability makes the
relative increase in unavailability more attractive as a measure of degradation.
The interference levels shown above could also be converted to a power flux density
(PFD) using the following equation:
5-35
R
G
IPFD
2
4
?
?
= (30)
Where:
G
R
 = the gain of the DBS receive antenna
PFD = the power flux density limit
? = the wavelength of the RF signal
Clearly, the PFD will vary with position of the DBS receiver as a result of the variations
in the gain pattern of the DBS antenna.  The equation above is suitable if the DBS receive
antenna gain is based on the dominant mode polarization.  See Section 4.5 for a discussion of
polarization.  If the polarization characteristics of the MVDDS and DBS antenna are such
that a more sophisticated polarization analysis is required, then criteria would be better
specified in terms of allowable interference levels, as shown here in this section.  Either way,
the characteristics of the DBS antenna must be known in order to determine whether a given
criterion is met.
6-1
Section 6
Conclusions and Recommendations
In the preceding sections, typical results for various scenarios have been provided.  In
addition, suggested sharing criteria have been provided.  In this final section, we draw
conclusions from those results and suggest a way forward for the FCC.  Section 6.1 discusses
the general feasibility of MVDDS/DBS bandsharing.  Section 6.2 provides a discussion of
some interference-mitigation techniques that might be used.  Finally, Section 6.3 highlights
major policy issues and makes recommendations for resolving them.
6.1  Feasibility of MVDDS/DBS Bandsharing
The analysis and testing performed by MITRE and described elsewhere in this report
have demonstrated that:
 MVDDS sharing of the 12.212.7 GHz band currently reserved for DBS poses a
significant interference threat to DBS operation in many realistic operational
situations.
 However, a wide variety of mitigation techniques exists that, if properly applied
under appropriate circumstances, can greatly reduce the geographical extent of the
regions of potential MVDDS interference impact upon DBS.
 MVDDS/DBS bandsharing appears feasible if and only if suitable mitigation
measures are applied.  Different combinations of measures are likely to prove best
for different locales and situations.
The question remains:  Do the potential costs of applying the necessary mitigatory
measures, together with the impact of the residual MVDDS-to-DBS interference that might
remain after applying such measures, outweigh the benefits that would accrue from allowing
MVDDS to coexist with DBS in this band?  Deciding that question is beyond the scope of
MITREs charter for the present study.  The FCC must make the decision after considering
the analytical and test results presented in this report, and after resolving the policy issues
discussed in Section 6.3.
6.2  Potential Interference-Mitigation Techniques
Techniques for preventing or reducing MVDDS interference in DBS receivers fall into
three general categories:
 Selection of MVDDS operational parameters
 Possible MVDDS system-design changes
6-2
 Corrective measures at DBS receiver locations
In the following subsections we identify potentially useful interference-mitigation
techniques in each category, and discuss the probable effectiveness of each in reducing the
potential impact and geographical extent of MVDDS interference upon DBS operations.  The
techniques can be used separately or in combination, although a few are mutually exclusive,
for reasons discussed below.
6.2.1  Selection of MVDDS Operational Parameters
The most important operational parameters that can be adjusted to control interference in
existing MVDDS system designs are transmitter power, frequency offset, tower height,
elevation tilt, and azimuthal orientation.  Properly selecting these parameters can reduce the
regions of potential interference impact, or direct much of that impact to areas containing
few DBS subscribers.
 Keeping the MVDDS transmitter power as low as possible without sacrificing
coverage requirements is often a prerequisite for minimizing interference to DBS.
 The use of a 7-MHz frequency offset between the MVDDS and DBS carriers has been
shown through MITREs testing to reduce effective interference levels by 1.7 dB.
The simulation whose results are shown on page B-17 demonstrates that this
reduction noticeably shrinks the areas in which DBS receivers are potentially affected
by MVDDS interference.
 Increasing the MVDDS transmitting antenna height reduces the sizes of the areas
susceptible to a given level of interference.  However, the simulations of pages  B-11
through B-15 indicate that substantial benefits may not accrue unless the tower height
is at least 100, or perhaps even 200, meters above the level of the DBS receiving
antennas in the surrounding area.  Fully utilizing this particular degree of freedom
might be controversial in many locales.
 Adjusting the elevation tilt of the MVDDS transmitting antenna is not controversial,
but our simulation results on page B-16 indicate that it may not be particularly
effective either.  Tilting the antenna up 5 reduces the interference-impact area but
shrinks the MVDDS coverage area in roughly the same proportion.  This presumably
means that more MVDDS towers (creating additional interference-impact areas)
would be needed to cover a given geographical region than if the antennas had not
been tilted.  The effect of a downward tilt has not been simulated, but there seems to
be little reason to think it would be any more successful.
 Pointing the MVDDS transmitting antennas away from the satellites, rather than
toward them as generally envisioned, could have beneficial effects in many
situations.  These are indicated by the simulation results of pages B-21 and B-23, and
by the outputs of several other simulations in which easterly and northerly MVDDS
6-3
transmitter boresight azimuths were used.  When the satellites are generally to the
south and their elevation angle is reasonably high, as in Denver, dramatic
improvements in interference protection appear possible when the MVDDS
transmitting antenna points north.  A major advantage of a north-pointing transmitter
is that it does not illuminate the relatively high-gain butterfly backlobes of typical
18 DBS dishes.  When satellite elevation angles are somewhat lower (as in Seattle)
the geometry is somewhat less favorable, but north-pointing seems to yield
significant benefits in all locales where it has been simulated.  Further field testing to
validate this concept is recommended.  Caveats:  The hot spots appearing on the
opposite side of the MVDDS transmitting antenna from the satellites (see pages B-7
and B-24) are somewhat largeralthough actually still quite smalland undoubtedly
more intense for a north-pointing than for a south-pointing MVDDS transmitter.  If
this technique is tested or used, care must be taken not to place the north-pointing
MVDDS antenna so close to the line of sight between a satellite and a DBS receiver,
and so close to the receiver itself, that physical damage to the receiver could result.
Another possible pitfall of this technique might be a reduction in opportunities for
natural shielding of the kind mentioned in 6.2.3 below.
6.2.2  Possible MVDDS System-Design Changes
Potential MVDDS design changes that might reduce the interference impact on DBS
downlinks include real-time power control, multiple narrow transmitting-antenna beams, the
use of circular polarization, and increasing the sizes of MVDDS receiving antennas.
 Real-time power control, which would reduce MVDDS transmitter power as
necessary to protect DBS downlinks from degradation during rain, has sometimes
been proposed as a technique for controlling MVDDS-to-DBS interference.
However, this might require an elaborate monitoring system.  Worse, it would
inevitably degrade MVDDS operation at the very times when it might be needed
most (i.e., when DBS downlinks were shut down by heavy rain).
 The use of multiple MVDDS transmitting-antenna beams, each having a much
narrower azimuthal beamwidth than the existing sectoral horns, might provide much
better flexibility than the present antenna design in directing the interference-impact
regions away from areas containing DBS subscribers.
 Circularly polarized MVDDS transmitting antennas, if they used the same system of
alternate senses for adjacent channels that is employed by DBS, might pose a
considerably smaller interference threat than the currently planned exclusive use of
horizontal polarization.  When a DBS signal on a particular channel is using RHC
polarization, the butterfly backlobes of the DBS receiving antenna are highly
susceptible to signals of the opposite (LHC) polarization sense for reasons discussed
earlier in the report; about 3 dB less susceptible to the horizontally polarized
6-4
MVDDS signals to which they would be exposed under present MVDDS designs;
and much less susceptible to MVDDS signals having the same (RHC) polarization as
the desired DBS signal.  The adjacent channels would be similarly protected, except
that the senses of the circularly polarized desired and undesired signals would all be
reversed, yielding the same net effect.  (However, this suggested mitigation technique
is not compatible with the existing 7-MHz frequency-offset method, and probably
would also negate the benefits of the previously suggested technique of pointing
MVDDS transmitting antennas away from the DBS satellites.  The frequency offset
would disrupt the necessary alignment of MVDDS and DBS channels, while north-
pointing might largely eliminate the benefits of butterfly-backlobe polarization
reversal, on which this technique depends.)
 Larger MVDDS receiving antennas, recently suggested by Pegasus, would increase
their achievable gains and hence the G/T ratios of MVDDS receivers.  This in turn
would allow an MVDDS system to cover an identical service area with a smaller
output power and hence with smaller resultant interference contours, as shown in the
simulation of page B-58.
6.2.3  Possible Corrective Measures at DBS Receiver Locations
Corrective measures that can be applied at DBS receiver installations include relocation
and retrofitting of existing DBS antennas, the use of alternative antenna designs, and the
replacement of older DBS set-top boxes.
 Relocation of DBS receiving antennas to put nearby buildings between them and
nearby MVDDS interferers, while still leaving desired satellites in view, is a well-
known corrective measure (sometimes called natural shielding) that would
undoubtedly be effective in many situations.
 The use of absorptive or reflective clip-on shielding for existing DBS antennas, to
block any direct lines of sight that might exist between their LNBs (antenna feeds)
and potentially interfering MVDDS transmitting antennas, is a technique that worked
quite well during MITREs open-air testing.
 DBS receiving-antenna replacement is a relatively expensive but potentially effective
mitigatory technique.  The simulation of page B-30 has shown the potential benefits
of using single-feed 24x18 antennas instead of the more commonly used 18
dishes.  Dual-feed 24x18 antennas would probably also work well with careful
selection of feed azimuths, to avoid aiming a butterfly backlobe toward an MVDDS
transmitter.  The use of Fortel planar arrays has also been proposed, although the
prominent grating lobes evident on the measured radiation patterns shown in section
4 could pose a problem.  Finally, research could be done to develop an improved
DBS receiving dish antenna having a better-shaped feed pattern and a lower ratio of
6-5
focal length to reflector diameter, with the intent of reducing sidelobe levels without
adversely affecting antenna gain.
 Replacement of older DBS set-top boxes may prove to be a useful mitigation
technique if more recent models are more resistant to in-band interference.
6.3  Policy Issues and Recommendations
If licensing of new MVDDS services is to be successful, while preventing significant
interference to DBS services, a number of policy issues need to be considered and resolved.
These resolutions naturally lead to a licensing and deployment process for new MVDDS
services.  On the basis of the results shown in other sections of the report, MITRE
recommends the following outline for this process:
1. The MVDDS service provider would compute a C/I ratio consistent with 10%
relative increase in unavailability.  This would be done for the locale of interest and
for the U.S. DBS satellites at each longitude in view of that locale.  The calculations
would use the satellite at each longitude with the worst baseline unavailability but
that still meets the baseline unavailability described below.  The C/I ratio would be
computed on the basis of a DBS receiver G/T of 11.2 dB and with a DBS receiver
threshold consistent with performance criterion #6 (also called video quality 6) plus
0.1 dB.
2. An MVDDS configuration would be chosen in a way that minimizes interference and
places interference-mitigation regions outside of populated areas to the maximum
extent possible.  Interference-mitigation regions are defined as those regions with C/I
ratios of less than the value computed in Step 1, plus 1.0 dB.  The MVDDS
configuration includes transmit power, antenna selection, antenna azimuth, antenna
tilt angle, antenna height, and any other parameters that impact DBS unavailability.
3. A construction permit would be obtained and the MVDDS site would be built.
4. The MVDDS service provider would implement interference-mitigation techniques at
the DBS receivers anywhere in the interference-mitigation region defined above.
These techniques would be implemented prior to obtaining a license to begin
transmitting.  Mitigation techniques include, but are not limited to, replacement of the
DBS antenna, moving the DBS antenna to take advantage of natural shielding, and
the placement of shields on, or near, the DBS antenna.
5. The MVDDS service provider would apply for a license to operate.  If the license
application requests an EIRP value greater than 14 dBm, a study of the impact of rain
scatter would be required.  Once the license is granted, the MVDDS transmitter
would be allowed to begin transmitting for test purposes.
6-6
6. The MVDDS service provider would measure C/I values at the output of the LNB for
all DBS receivers in the interference-mitigation region.  The MVDDS service
provider would implement any further mitigation techniques necessary to keep the
measured C/I lower than the C/I value computed in Step 1 above.
7. A final license to begin operation would be granted.
Some further discussion of this process outline may be helpful.  A number of measures of
interference have been suggested in Section 5.2, including:
 Maximum total unavailability
 Maximum increase in unavailability
 Maximum relative increase in unavailability
 Minimum C/I
 Maximum interference power at the DBS LNB
 Maximum PFD
 Maximum EIRP
Of these MITRE believes that relative increase in unavailability is particularly
advantageous, since it prevents large increases in absolute unavailability where initial
unavailability is small.  This approach recognizes that the increase in unavailability that is
noticeable to the consumer depends on what the consumer is used to.  An increase of 2.86%
seems very small and there is precedent for 10% increase as a criterion.  We note that C/I
ratios are measurable at the LNB output.  Also, the C/I ratio can be associated with relative
increase in unavailability by straightforward calculations.
Video quality 6 (VQ6) is easily measurable, and many results based on VQ6 are provided
here in this report. Based on results shown in Figure A-7, the performance curves are very
steep at the VQ6 point.  The threshold for VQ6 plus 0.1 dB is approximately the same as the
threshold for VQ7.
The interference-mitigation region is defined as the region where the C/I value is 1.0 dB
above the C/I computed in step one above.  This is done to ensure that vulnerable DBS
receivers are not missed due to measurement inaccuracies or inaccuracies in the modeling.
The process described above could form the basis for a licensing policy for MVDDS
services.  However, a number of additional policy issues should be considered.  These issues
and questions are discussed below, along with MITREs recommendation to the FCC.
 Should future DBS customers be protected and for how long?
Recommendation: Yes, future DBS customers should be protected for as long as the
MVDDS transmitter operates.  The MVDDS service provider would need to measure
6-7
C/I values and provide mitigation solutions to these new customers in the
interference-mitigation region.
 Test results and analyses have been based on known MVDDS waveforms.  Should
new waveforms be allowed?
Recommendation: New waveforms create an unknown vulnerability. MITRE
recommends that these not be licensed without further study.
 Should the evaluation of sharing consider any DBS satellite in the geostationary arc,
or should only existing U.S. satellites be considered?  What about new U.S.
satellites?
Recommendation: DBS receivers operating with new and different satellites could be
at risk in unforeseen ways.  MITRE recommends that any satellites not addressed in
the current report be studied further.
 If changes and improvements are made to any DBS system waveform, how should
this impact policy?
Recommendation: Results in this report are based on specific systems with known
parameters.  MITRE recommends that any new DBS waveforms be subject to further
study.
 Should DBS satellites with weak coverage be protected?  If so, how weak can these
be and at what level should they be protected?  (See examples in Section 5.2.3 and
elsewhere.)  What is the maximum baseline and degraded unavailability that should
be allowed?
Recommendation: MITRE recommends that only DBS satellites with baseline
unavailabilities of 100 hours/year or less when operating without MVDDS
interference into a DBS antenna with G/T of 11.2 dB/K be protected.  DBS receivers
operating with satellites that do not meet this criterion should not be protected from
MVDDS interference when operating with such satellites.
 How should the advent of new DBS antennas affect the policy for MVDDS
licensing?
Recommendation: DBS antennas with G/T performance below 11.2 dB/K could
seriously degrade DBS availability in rain.  In all cases the C/I criterion must be met.
If the MVDDS service provider opts to mitigate MVDDS interference with the use of
a different antenna, the replacement antenna should have a G/T at least as great as
that of the original antenna.
 Should other causes of unavailability be included in the total budget?
Recommendation: Other sources of outage should be considered, if they are
significant and if their effect is known and documented.  Sun-transit outages are an
example.
6-8
 MVDDS antenna backlobes can interfere with a DBS antenna main beam.  This
would typically occur close to the MVDDS transmitter, generally north of the
antenna.  These regions are typically very small.  Should very small regions of
interference be exempted because of their small size?
Recommendation: These small regions should not be exempted because of their size.
All regions of the interference-mitigation region should be considered, regardless of
size.
 Should MVDDS mitigation be based solely on customer complaints?
Recommendation: MITRE believes that DBS customers may not know what is
causing a particular outage, or the reason for its duration.  Consequently, mitigation
should not await DBS customer complaints.  MITRE believes that mitigation should
be done proactively, regardless of the presence or absence of such complaints.
 How much time should the MVDDS service provider be allowed in order to
implement mitigation to the DBS receivers?
Recommendation: To the maximum extent possible, mitigation should be
accomplished prior to a license being granted for MVDDS operation.
MITRE believes that with implementation of the licensing process and other policy
recommendations outlined above, spectrum sharing between DBS and MVDDS services in
the 12.212.7 GHz band is feasible.  However, MITRE recognizes that it is the FCC that
must ultimately resolve the various policy issues and the approach to licensing new MVDDS
services.
RE-1
List of References
Barker, J. H., and P. Michalopoulos, 31 January 2001, Answers from the DBS Operators to
Questions Posed by the MITRE Corporation, DIRECTV and EchoStar.
Barker, J. H., and P. Michalopoulos, 14 March 2001, Additional Answers from the DBS
Operators to Third Set of Questions Posed by The MITRE Corporation, DIRECTV and
EchoStar.
Combs, B., 9 February 2001, Answers to the Second Set of Questions for the MVDDS
Industry from The MITRE Corporation, email document, Broadwave USA.
DIRECTV, 31 March 2000, Ex Parte submission to FCC regarding ET Docket No. 98-206.
European Telecommunication Standard, December 1994, Digital broadcasting systems for
television sound and data services; Framing structure, channel coding and modulation for
11/12 GHz satellite services, ETS 300 421.
Evans, G. E., 1990, Antenna Measurement Techniques, Artech House, Boston, MA.
Federal Communications Commission (FCC) DA 01-441, 16 February 2001, Fourth
Erratum, First Report and Order and Further Notice of Proposed Rule Making
(FCC 00-418), Washington, DC.
International Telecommunications Union (ITU), 1997, Propagation Data and Prediction
Methods Required for the Design of Earth-Space Telecommunication Systems,
ITU-R P.681-5.
ITU, 1999a, Propagation Data and Prediction Methods Required for the Design of Earth-
Space Telecommunication Systems, ITU-R P.618-6.
ITU, 1999b, Characteristics of Precipitation for Propagation Modeling, ITU-R P.837-2.
ITU, 21 September 2000, Digital Multiprogramme Television Systems for Use by Satellites
Operating in the 11/12 GHz Frequency Range, Document 6/35-E.
Slater, D., 1991, Near-Field Antenna Measurements, Artech House, Boston, MA.
Telecommunications Systems, 6 April 2001, Letter to The MITRE Corporation,
Washington, DC.
A-1
Appendix A
Testing of DBS Set-Top Boxes in the Presence of
Northpoint MVDDS Interference
A.1  Overview of Test Configuration for Receiver Degradation Measures
A simplified view of the test configuration used to study the impact of MVDDS
interference on DBS systems is shown in Figure A-1.  In general, a closed DBS link is
perturbed via the insertion of additional interference signals.
Signal quality is monitored through observation of the picture and sound quality as
observed through a television connected to a DBS set-top box.  Signal quality, C/(N+I) or
carrier to noise plus interference ratio is calculated from data measured with an Agilent
8564E spectrum analyzer.  An SAT9520 DBS installers tool was also used to measure C/N
during interference experimentation.
In order to have independent control of both the carrier-to-noise-plus-interference, and
the noise-to-interference power ratios, addition of both Gaussian noise and Northpoint
interference was necessary.
Specific details of the test set-up and procedures are discussed in the following sections.
? ?
AWGN
Generator
Interference
Source
DB S Set-top
Box
SAT 9520
Installer's
Tool
Agilent
8564EC
Spectrum
Analyzer
Figure A-1.  Functional Overview of DBS Video Test Configuration
A-2
A.2  Details of the Test Configuration
Noise/COM VFX
7112
Noise Generator
Narda 4372A-3
3 WAY
SPLITTER
ZFBT-6G-
FT
Bias Tee
Minicircuits
ZHL-42
RF Amp
Minicircuits
ZFL-2000
RF AMP
Combiner
0.1 dB step
atten
1 dB
Step
Combiner
DBS Signal from
Sat Dish/LNB
ZFBT-6G-
FT
Bias Tee
Step atten
for Signal
and Noise
Satellite
Receiver/Decoder
 Box
Agilent 8564EC
Spectrum Analyzer
DBS Installer's Tool
SAT9520
+15V bias for LNB
Interference Source
(e.g. AWS QPSK,
Northpoint, Northpoint
with adjacent channels)
1.0 dB
Step Atten
ZFBT-6G-
FT
Bias Tee
Minicircuits
ZFL-
RF AMP
0.1 dB
Step
A
B
CD
E
Figure A-2.  Details of the Test Configuration for DBS Video Testing
Figure  A-2 shows, in detail, the test configuration used to measure the impact of
interference from MVDDS on DBS systems.  A Noise/Com Model 7112 noise generator is
amplified using two cascaded RF amplifiers, namely a Mini-circuits ZHL-42 and a Mini-
circuits ZFL-2000, respectively.  The amplified noise source level is controlled by both the 1
dB steps available on the noise generator, and the 0.1 dB step attenuator labeled A in
Figure A-2.  MVDDS interference is added to the noise using an Anzac H-8-4 combiner.
Interference levels are controlled through step attenuator B.  The power of the combined
noise and interference is controlled using attenuators C and D and is then added to the DBS
LNB video signal using another Anzac H-8-4 combiner.  Attenuators C and D control the
level of the composite noise and interference, N+I, relative to that of the DBS signal, C. A
level of 15 volts bias is made available to the DBS receive satellite dish LNB by way of a
ZFBT-6G-FT bias tee through the combiner.  Attenuator E is used to control the composite
DBS signal, interference, and noise level into the satellite decoder box.  The composite
A-3
signal is split three ways using a Narda 4372A-3 signal splitter. One output is fed to the
satellite decoder box, a second is fed to an Agilent 8564EC spectrum analyzer, and a third to
the SAT 9520 DBS Installers Tool.  The installers tool monitors DBS signal quality,
displaying signal strength, bit error rate, etc.  A Mini-circuits ZFL-2000 RF amplifier is used
to improve the noise performance of the spectrum analyzer.
A.2.1  Audiovisual (A/V) Signal Quality Determination
Due to the nature of the encoded DBS signal, video and/or audio degradation occurs over
a very narrow region of carrier-to-noise plus interference, C/(N+I), prior to complete loss of
signal lock. Degradation in A/V quality originating from a digital broadcast is unlike that
from an analog broadcast, where picture quality is very subjective.  Instead, degradation is
quite noticeable, and occurs in burst fashion when uncorrectable bit errors are presented to
the Motion Picture Experts Group (MPEG) decoder.  For low bit error rates, errors are
corrected by the error correction coding inherent in the system. Video and audio impairments
occur when the number of bit errors exceeds what is correctable by the concatenated code.
Video impairments manifest as sudden pixelization in the image.  Audio errors manifest as a
sudden pop or chirp sound.  In general, the rate of audio and video error occurrences
increases as the C/(N+I) ratio degrades.  A video/audio quality criteria set was established for
the purpose of assigning a quality measure. See Table A-1.
Table A-1.  DBS A/V Quality Criteria
Assigned Quality Level
(9=perfect)
Video/audio characteristics
(average)
9 Perfect video/audio
8 1 video/audio error per 30 minutes
7 < 1 error per minute, but > than 1 per 30 minutes
6 < 1 error per 15 seconds, but > 1 error per minute
5 > 1 error per 15 seconds
4 Freeze framing and pixelization  occurring; audio
chirping and momentary blanking
3 Mostly pixelized, mostly frozen, mostly audio blanked
2 Occasional video acquisition, no audio
1 Loss of lock, no signal acquisition
A-4
A.3  Power Measurement for DBS, MVDDS, and Noise Signals
Evaluating the DBS system performance in the presence of MVDDS interference
required that a consistent, repeatable measurement technique be used throughout the duration
of the testing.  The following sections describe the settings used for the measurement
equipment as well as the rationale for choosing the measurement bandwidth.
A.3.1  Signal/Noise Power Measurements Using the Agilent 8564EC Spectrum Analyzer
Signal and noise power measurements are performed with an Agilent 8564EC spectrum
analyzer.  The analyzer settings used throughout the testing are given in Table A-2.
Table A-2.  Spectrum Analyzer Settings
Resolution bandwidth 300 kHz
Video bandwidth 3 kHz
RF Attenuation 0 dB
Center frequency Center of DBS video IF frequency
Span 30 MHz
Reference level -20 dBm
A.3.1.1  Signal Power Measurements
Using the Agilent 8564EC spectrum analyzer, the power occupied bandwidth for the
DBS video signal was performed at various percentages of the total power.  While
performing these measurements, the noise input is disabled.  The results are presented
Table A-3.
Table A-3.  Power Occupied Bandwidth of DBS Signal
Percentage of Total DBS Signal Power Occupied Bandwidth
50% 10 MHz
75% 15 MHz
90% 18.4 MHz
95% 20.0 MHz
96% 20.46 MHz
97% 21.04 MHz
98% 21.7 MHz
99% 22.7 MHz
A-5
In order to perform total signal, noise and interference power measurements, a common
measurement bandwidth must be chosen.  Recall that an important goal of the test
configuration of Figure A-2 was to allow for independent control of the received carrier
power, C, the total noise power, N, and the interference power, I.  Special consideration was
given to measurement of the total carrier power, C.
Because the carrier power was a measurement of a live satellite signal, it is not possible
to measure without consideration of the atmospheric noise.  To overcome the inaccuracy
introduced by the noise, a receive dish much larger than typically used by the consumer (90
cm) was used to collect the signal.  Use of this large dish resulted in received carrier-to-noise
ratios much greater than 10dB.  Because of this, the intermediate frequency (IF) power
measured at the output across the bandwidth of a single transponder could be attributed
entirely to the radiated space vehicle (SV) power.  To further substantiate, the 90cm dish was
pointed at clear sky.  Although the resulting measure of sky noise power was still above
the noise floor of the spectrum analyzer, its power level did not modify the least significant
digit of the former carrier power measurement when subtracted. That is to say that the total
carrier power plus noise measured when the large dish was appropriately pointed at the DBS
satellite, minus the sky noise power measured when pointed at clear sky was for all
practical purposes, equal to the total power measured in the first measurement.
Although a bandwidth of 24 MHz would account for the entire power contained in the
DBS signal, the signal to noise ratio of the received satellite signal degrades in the roll off
region of the transponder. Thus it was more accurate to make the signal power measurements
in as small a bandwidth as was reasonable.  As an alternative to 24 MHz, power and noise
measurements can be made over the effective bandwidth of the DBS signal.
The effective bandwidth of the DBS signal is found by computing the bandwidth of a
uniformly rectangular spectrally shaped signal with spectral density equal to that of the
center of the DBS signal, which would contain the same total power as the DBS signal.  See
figure A-3.  Measurements of the effective signal bandwidth were measured to be 20 MHz.
This can be visualized by observing that the 50% and 75% power occupied bandwidths (over
which the spectral density is flat) are 10 MHz and 15 MHz, respectively.  Note however that
when using a 20 MHz bandwidth to measure the DBS signal power, a 0.2 dB underreporting
occurs.  This is because only 95% of the DBS signal power (10*log(0.95) = -0.2 dB) is
contained in that bandwidth.  A correction factor of +0.2 dB was added to all DBS signal
power measurements to account for the missing power in the tails.
Signal power measurements are obtained using the Measure/User softkey available on
the spectrum analyzer.
A-6
B
eff 
=20 MHz
24 MHz
Equal integrated
power
Figure A-3.  Notional Depiction of DBS Effective Bandwidth
A.3.1.2  Noise Power Measurements
Noise power measurements are performed using the Measure/User softkey available on
the analyzer.  A measurement bandwidth of 20 MHz is specified as a parameter to the
analyzer using the appropriate entry keys.  While performing noise measurements, the DBS
video signal is disconnected.  The analyzer computes integrated noise power over the
specified bandwidth.
A.4  Notes on Interference Testing
This section contains notes applicable to the equipment and methods of the testing that is
articulated in the subsequent sections.
A.4.1  Test Objectives
The goal of the receiver testing was to characterize how the DBS systems performed in
the presence of MVDDS interference at various levels of C/(N+I) and N/I.  Throughout the
testing, N/I was varied to achieve the following levels:  +infinity (noise only), +10dB, +3dB,
0 dB, -3dB, -10dB, and infinity (MVDDS interference only).   Once N/I was established,
the aggregate combination of N+I was raised in power to degrade the signal quality to a pre-
determined level.
A.4.2  DBS Equipment
In order to maintain the independence of the tests, DBS set-top boxes were procured that
were not traceable back to MITRE.  This was done thanks to a close family member of one
of the members of the testing staff, (with a different surname), independently procuring DBS
set-top boxes for both Dish TV and DIRECTV at retail locations that were not in the
immediate vicinity of the Bedford facility.
The set top equipment procured was Philips Magnavox Dish model DSK2812S and RCA
DIRECTV plus! model DRD420RE.  These set-top boxes are shown in Figure A-4.
A-7
Figure A-4.  Set-Top Boxes Used in Receiver Testing
Although a great deal of set-top equipment was made available by the DBS
manufacturers, it was not deemed acceptable for use in an independent test, and the
constraints of time and budget did not permit any detailed testing of that equipment.
A.4.3  MVDDS Equipment
The only MVDDS equipment received for testing was a single channel transmitter made
by L3 Communications.  The unit consists of an AAA NTSC to MPEG converter, a BBB
quadrature phase shift keying (QPSK) modulator, and a CCC amplifier.  The unit is shown in
Figure A-5.
A-8
Figure A-5.  Northpoint MVDDS Single Channel Transmitter
A.4.4  Signal Quality Level 6
Initial experimentation injecting representative MVDDS interference signals into closed
DBS links revealed it was simple and reliable to control the relative rate of occurrences of
disturbances to the DBS signal using the test configurations identified in Appendix A.
However reliably measuring a small number of disturbances that occurred over the course of
an hour (or even hours for that matter) is extremely time consuming and potentially fraught
with inaccuracy due to too small a sample space, and the likelihood of changing atmospheric
conditions over long periods of time.
An A/V quality level of 6, (see Table A-1), an audio or visual degradation occurring on
the average of 1 to 4 times per minute was chosen as the measurement standard.  This A/V
quality level was chosen primarily for its repeatability and the reduction of time in test
execution that it offered.  Additionally, an A/V quality level of 6 occurs roughly mid-range
in the narrow span over which signal degradation can actually be observed, between no
degradation and total loss of signal lock.
A-9
Selection of video quality 6 is not intended to be an advocation of that level as either
acceptable or unacceptable to the consumer.  Rather it is a convenient point to identify in a
short range between perfect quality and loss of lock in the vicinity of the mean of that range.
A.4.4.1  Dynamic Allocation of DBS Transponder Bandwidth to Stations
Another factor important to mention is that the bandwidth for any given channel is
dynamically allocated from a transponder that carries the burden of several channels.  This
adjustment is made automatically based upon the need for bandwidth post compression.
Typically, television scenes with more action result in lower compression ratios and require
more bandwidth for quality transmission.
Typically, a fixed C/(N+I) would result in a fixed bit error rate, but the number of errors
per second would be the largest on those channels consuming the most instantaneous
bandwidth on that transponder.  Thus every attempt was made to measure video quality
during programming sequences that had high levels of action.
The impact to the laboratory measurements of this artifact of the DBS systems is that a
fixed A/V quality may trace back to bit error performances between transponders.
Additionally, since the uncorrected bit errors will be distributed ratiometrically according to
the channel utilization relative to the total transponder bandwidth, the measured C/(N+I)
required to drive one particular channel to A/V quality 6 may be different than another
channel.  However, since the range of perceptible A/V degradation (between A/V quality 9
and loss of lock) is relatively narrow, then comparative results between channels on different
transponders should compare reasonably.
A.4.5  Elimination of Drive Power as Testing Variable
In order to reduce the dimensionality of the testing, it was necessary to determine
whether the drive power of the signal to the DBS set-top box had an impact on the C/(N+I)
that would degrade the signal quality.  The DBS set-top boxes are specified for a drive input
between 25 dBm to 65 dBm.  A visual test was performed.  With the drive power
attenuated to near the 65 dBm minimum, the C/(N+I) was adjusted so that the video quality
was within 1 dB of noticeable degradation.  Drive power was successively increased in 5 dB
steps.  After each step, 1 additional dB of interference was added, and a visually equivalent
degradation to the quality of the video signal at the previous step was observed.  The 1 dB of
additional interference was then removed prior to the next step.  This test was performed at
several N/I ratios.
Figures A-6 and A-7 are presented (beyond the anecdotal results discussed above) to
show the impact of changing the drive power.  In Figure A-6 the resulting signal quality for
varying C/(N+I) are shown for 2 different drive powers, -45 dBm and 55 dBm (DIRECTV).
In Figure A-7 the conditions are 30 dBm and 55 dBm are used for DISH Network (i.e.,
A-10
EchoStar).  Note the consistency between the C/(N+I) values required to drive the signal
quality to level 6, for both systems.
Q
u
ality
 M
e
asure
DirecTV
Video Quality vs. C/(I)
Interference Only (Noise = 0)
Signal into Decoder = -45 dBm
0
1
2
3
4
5
6
7
8
9
10
0 1 2 3 4 5 6 7 8 9 10 11 12
C/(I) (dB)
Q
ualit
y
 Me
a
s
u
r
e
DirecTV
Video Quality vs C/(I)
 Interference Only (Noise = 0)
Signal into Decoder = -55 dBm
0
1
2
3
4
5
6
7
8
9
10
0 1 2 3 4 5 6 7 8 9 10 11 12
C/(I) (dB)
Figure A-6.  Comparison of 2 Different Drive Powers for DIRECTV
Q
uality
 M
easure
DISH Network
Video Quality vs. C/(N+I)
AWS Interference + Noise (N/I = 0 dB)
Signal into Decoder = -30 dBm
0
1
2
3
4
5
6
7
8
9
10
012345678910112
C/(N+I) (dB)
Q
ualit
y
 M
easure
DISH Network
Video Quality vs. C/(N+I)
AWS In te rfe re n ce  + No is e  (N/I = 0 d B)
Signal into Decoder = -55 dBm
0
1
2
3
4
5
6
7
8
9
10
012345678910112
C/(N+I) (dB)
Figure A-7.  Comparison of 2 Different Drive Powers for Dish TV
A.4.6  Selection of Programming
As discussed above, programming with action sequences was chosen due to the
likelihood of consumption of larger instantaneous portions of the transponder bandwidth.
Because of the flexibility of the equipment, any television channel could be targeted.
Prior to execution of tests, available channels were scanned for the most promising television
program.  Upon selection of programming, the corresponding transponder was identified.
The selected television program was used for the duration of any test.
A-11
A.4.7  Determination of Transponder Transmitting a Particular Television Channel
As discussed above, every effort was made to choose programming that contained
frequent action scenes, and ostensibly consumed an above average share of the transponder
bandwidth.  Upon determination of appropriate programming, we determined the
corresponding transponder from which the programming was being broadcast by moving a
high powered tone to the (I.F.) center frequency of each of the transponders. As the power of
the tone was sufficient to jam any single transponder at a time, determination of the
appropriate transponder was a matter of visual inspection.
A.5  DBS A/V Quality 6 in the Presence of Northpoint MVDDS
Interference Using 70 MHz IF Output Translated to L Band with
Simulated Adjacent Channels
Some MVDDS interference experiments were conducted upon arrival of the MVDDS
transmitter suite, but prior to an appropriate LNB downconverter being available.  To
proceed without the LNB, it was necessary to make use of the 70 MHz IF output of the
MVDDS transmitter.
A.5.1  Test Configuration
The configuration that properly mixed the IF output of the Northpoint MVDDS
transmitter and combined the mixed output with the arbitrary waveform synthesizer (AWS)
to provide the adjacent MVDDS channels is shown in Figure A-8.
Northpoint
Transmitter
(70 MHz IF Output)
Minicircuits
ZFM-2
K&L
5BT-750/1500-2-N/N
Narda 4372A-3
3 WAY
Combiner
AWS Generator
(Adjacent
Channels Only)
HP 8648B
Freq = DBS IF
+ 70 MHz
3 dB
Interference
Source
3 dB 3 dB
0.1 dB
D
Figure A-8.  Configuration for Northpoint Transmitter IF Output with
Adjacent Channels
The 70 MHz output is attenuated using a 3 dB pad, upconverted using a Mini-circuits
ZFM-2 mixer terminated by a 3 dB pad, and filtered with a K&L tunable bandpass filter.
The signal at the output of the filter is combined (for cases with adjacent channel testing)
with an arbitrary waveform synthesizer programmed to simulate MVDDS adjacent channels.
A-12
The signals are combined with a Narda 4372A-3 combiner, with the third port terminated in
50 ohms.  The combined signal labeled as interference source is applied to the interference
source input of Figure A-2.  Relative power levels between the MVDDS signal and the AWS
adjacent channels are adjusted using the Northpoint MVDDS Tx control keypad, the PC
control interface to the AWS, and the fine adjustment attenuator D.  The interference signal
resulting from the combination of the Northpoint MVDDS IF output and the AWS is shown
in Figure A-9.
Figure A-9.  Single Channel MVDDS IF Interference Plus Adjacent Channels
Generated from Arbitrary Waveform Synthesizers
A.5.2  Test Results
Results for DIRECTV and Dish TV are shown in Figure A-10 and Figure A-11
respectively.  Note that values for Figures A-10 and A-11 were determined at N/I ratios of 
infinity (MVDDS interference only), -10 dB, -3dB, 0 dB, 3dB, 10 dB, and +infinity (noise
only).  Both DIRECTV and Dish TV are more resilient to the constant envelope, Northpoint
MVDDS signal, than to the Gaussian noise. Results for +infinity and infinity are plotted on
the +30 and 30dB points, respectively.
Note the proximity of the SAT9520 measurement to the spectrum analyzer measurement
in the noise-only case.  Insufficient information is available about the SAT9520 to provide an
A-13
accurate scaling factor that would account for the small differences in measurement
bandwidth between the spectrum analyzer and the SAT9520.
DirecTV C/(N+I) Threshold vs. N/I;
Translated Nrthpt IF Interference w/ 
Simulated Adj Channels + Noise
2
3
4
5
6
7
8
-30 -20 -10 0 10 20 30
N/I (dB)
C/(N+I) Threshold
Figure A-10.  Carrier-to-Noise-Plus-Interference Required to Degrade DIRECTV to
A/V Quality 6 Vs. Noise-to-Interference Power Ratio; 70 MHz IF
SAT 9520 C/N Reading
A-14
Dish Network C/(N+I) Threshold vs. N/I;
Nrthpt Translated IF Interference w/ 
Simulated Adj Channels + Noise
2
3
4
5
6
7
8
-30 -20 -10 0 10 20 30
N/I (dB)
C/(N+I) Threshold
Figure A-11.  Carrier-to-Noise-Plus-Interference Required to Degrade Dish TV to A/V
Quality 6 Vs. Noise-to-Interference Power Ratio; 70 MHz IF
A.6  DBS A/V Quality 6 in the Presence of Northpoint MVDDS
Interference Using RF Output with Simulated Adjacent Channels
The test results in Section A.5 were repeated using the 12 GHz RF output of the
Northpoint MVDDS transmitter coupled into an LNB.
A.6.1  Test Configuration
The configuration for interference testing using a Northpoint MVDDS Transmitter and
LNB downconverter is shown in Figures A-2 and A-12.  The signal made available to the
Interference Source in Figure A-2 is generated in Figure A-12.
SAT 9520 C/N Reading
A-15
Northpoint
Transmitter
RF Output
90 dB
Interference
Source
3 dB
Northpoint Low
Noise Block
Downconverter
Bias Tee
Narda 4372A-3
3 WAY
Combiner
AWS Generator
(Adjacent
Channels Only)
+15V
RF
Figure A-12.  Interference Test Configuration Using Northpoint Transmitter with LNB
The 12 GHz output of the Northpoint MVDDS transmitter is attenuated using a 90 dB
attenuator.  This signal is applied to an LNB downconverter.  15 volts is applied to the LNB
using a bias tee.  The RF signal is applied to the input of a Narda 4372A-3 combiner.  An HP
AWS programmed to generate left and right adjacent channels, is applied to the combiner.
The third port of the combiner is terminated in 50 ohms.  The adjacent channel power level is
controlled by the PC interface to the AWS generator.  This level is adjusted to equalize the
adjacent channel to the Northpoint interference level.
Attenuators A and B are adjusted to fine-tune the relative levels of the noise and
interference power.  Attenuator C is used to control the composite noise and interference
level relative to that of the DBS signal.  The composite output of the Northpoint MVDDS
transmitter and AWS at L-Band IF is shown in Figure A-13.
A-16
Figure A-13.  Single Channel MVDDS Downcoverted RF Interference Plus Adjacent
Channels Generated from Arbitrary Waveform Synthesizers
A.6.2  Test Results
Data is recorded at various noise to interference power levels, namely, +infinity, (noise
only), +10 dB, +3 dB, 0 dB, -3 dB, 10 dB, and infinity (interference only).  As in the
previous section, results for +infinity and infinity are plotted on the +30 and 30dB points,
respectively.
The results are shown for Direct TV and Dish TV in Figure A-14 and Figure A-15,
respectively.
The same trend is observed relative to the resilience to the constant envelope QPSK
MVDDS signal as compared to Gaussian noise as was observed in the previous section.
Note as well the Proximity of the SAT9520 Measurement in the noise-only case to
spectrum analyzer measurements.  Insufficient information is available about the SAT9520
to provide an accurate scaling factor that would account for differences in measurement
bandwidth between the spectrum analyzer and the SAT9520.
A-17
DirecTV C/(N+I) Threshold vs. N/I;
Nrthpt Interference w/ Adj Channels + Noise
2
3
4
5
6
7
8
-30 -20 -10 0 10 20 30
N/I (dB)
C/(N+I) Threshold
Figure A-14.  Carrier-to-Noise-Plus-Interference Required to Degrade DIRECTV to
A/V Quality 6 Vs. Noise-to-Interference Power Ratio; 12 GHz RF Output
SAT 9520 C/N Reading
A-18
Dish Network C/(N+I) Threshold vs. N/I;
Nrthpt Interference w/ Adj Channels + Noise
2
3
4
5
6
7
8
-30 -20 -10 0 10 20 30
N/I (dB)
C/(N+I) Threshold
Figure A-15.  Carrier-to-Noise-Plus-Interference Required to Degrade Dish TV to
A/V Quality 6 Vs. Noise-to-Interference Power Ratio; 12 GHz RF Output
A.7  DBS A/V Quality 6 in the Presence of Northpoint MVDDS
Interference Using RF Output with +7 MHz Offset and Simulated
Adjacent Channels
Northpoint had identified a 7 MHz frequency offset between the center frequencies of the
MVDDS channelization and DBS channelization as one potential means of isolation from the
DBS system at their disposal.  This section details the laboratory work to substantiate that
claim.
A.7.1  Test Configuration
The configuration for interference testing using a Northpoint transmitter with +7 MHz
offset and LNB downconverter with adjacent channels is shown in Figure A-16.
SAT 9520 C/N Reading
A-19
Northpoi nt
Transmitter
RF Output @ D BS +
7 MHz
90 dB
Interf erence
Source
3 dB
Northpoi nt Low
Noise Bloc k
Downconverter
Bias Tee
Narda 4372A-3
3 WAY
Combi ner
AWS Generator
@ Left A dj.
Channel +7
MHz
+15V
RF
Figure A-16.  Interference Test Configuration Using Northpoint Transmitter with +7
MHz Offset and LNB Downconverter
The RF output of the Northpoint MVDDS transmitter centered at the DBS frequency
with a + 7 MHz offset is attenuated using a 90 dB attenuator.  The 7MHz offset was achieved
through programmability in the Northpoint MVDDS transmitter and verified with the
Agilent spectrum analyzer.  This signal is applied to an LNB downconverter.  15 volts is
applied to the LNB using a bias tee.  The resulting L-band IF signal is applied to the input of
a Narda 4372A-3 combiner.  An HP AWS programmed to generate the left adjacent channel
+ 7 MHz (at L band IF frequency), is applied to the combiner.  The third port of the
combiner is terminated in 50 ohms.  The adjacent channel power level is controlled by the
PC interface to the AWS generator.  This level is adjusted to equalize the adjacent channel
level to that of the Northpoint MVDDS interference level.
Attenuators A and B are adjusted to fine-tune the relative levels of the noise and
interference power.  Attenuators C and D (of Figure 2) are used to control the composite
noise and interference level relative to that of the DBS signal.
A view of the total (actual plus simulated) MVDDS output translated into the L-band IF
of the DBS system is shown in Figure A-17.
A-20
Figure A-17.  Single Channel MVDDS (with 7 MHz Offset With Respect to DBS
Channelization) Downcoverted RF Interference Plus One Adjacent Channel Generated
from Arbitrary Waveform Synthesizer
A.7.2  Test Results
Data is recorded at various noise and interference levels, namely with noise only,
interference only, and noise to interference ratios of +10 dB, +3 dB, 0 dB, -3 dB, and 10
dB.  As in the previous section, results for +infinity and infinity are plotted on the +30 and
30dB points, respectively.
The results for DIRECTV are compiled in Figure A-17.  The same trend is observed
relative to the resilience to the constant envelope QPSK MVDDS signal as compared to
Gaussian noise.
Note as well the proximity of the SAT9520 measurement in the noise-only case to
spectrum analyzer measurements.  Insufficient information is available about the SAT9520
to provide an accurate scaling factor that would account for differences in measurement
bandwidth between the spectrum analyzer and the SAT9520.
A-21
DirecTV C/(N+I) Threshold vs. N/I;
Nrthpt Int. 7 MHz Offset w/ Adj Channels + 
Noise
2
3
4
5
6
7
8
-30 -20 -10 0 10 20 30
N/I (dB)
C/(N+I) Threshold
Figure A-18.  Carrier-to-Noise-Plus-Interference Required to Degrade DIRECTV to
A/V Quality 6 Vs. Noise-to-Interference Power Ratio; Northpoint MVDDS 12 GHz RF
Output, + 7 MHz Offset from DBS Channelization
An additional test was performed with regard to the 7 MHz offset.  Power over the 20
MHz bandwidth was computed for the Northpoint MVDDS transmitter plus adjacent
channel, when the center frequencies of the DBS signals were aligned, and when the signals
were offset by 7MHz.  We noted that a power difference of 1.2 dB between the 2 signals,
(the perfectly aligned signal had the greater power.)  This 1.2 dB of additional isolation, that
is not obvious from Figure A-18 was factored into total MVDDS power that would be
required to degrade the DBS signal unavailability to a specified level.
A.8  DBS A/V Quality 6 in the Presence of Northpoint MVDDS
Interference Using Open Air RF Transmission
This section describes the results of testing when a transmitted Northpoint MVDDS
signal was used as interference source.
A.8.1  Test Configuration
Transmitted Northpoint MVDDS signals were coupled into a DBS receive dish mounted
on a movable pedestal.  The pedestal is capable of motion in both azimuth and elevation, and
was oriented as to maximally couple energy from the Northpoint MVDDS transmit antenna
SAT 9520 C/N Reading
A-22
into the L-band IF of the receive Dish.  This maximal coupling occurred when the there was
a direct-ray path between the transmit antenna and the Dish LNB.  This coupling appeared to
be relatively insensitive to small changes in elevation, as long as the direct ray path
remained.
The configuration for the test is shown in Figure A-19.
Noise/COM VFX
7112
Noise Generator
Narda 4372A-3
3 WAY
SPLITTER
ZFBT-6G-
FT
Bias Tee
Minicircuits
ZHL-42
RF Amp
Minicircuits
ZFL-2000
RF AMP
Combiner
0.1 dB step
atten
1 dB
Step
Combiner
DBS Signal
ZFBT-6G-
FT
Bias Tee
Step atten
for Signal
and Noise
Satellite
Receiver/Decoder
 Box
Agilent 8564EC
Spectrum Analyzer
DBS Installer's Tool
SAT9520
+15V bias for LNB
1.0 dB
Step Atten
ZFBT-6G-
FT
Bias Tee
Minicircuits
ZFL-
RF AMP
0.1 dB
Step
A
B
CD
E
Northpoint
Transmitter
Interference
Figure A-19.  Configuration for Open Range Testing of Northpoint MVDDS
Interference to DBS Systems
The Northpoint transmitter/antenna broadcasts a signal which is received by a DBS dish
antenna, and is converted to L band IF by the LNB contained within the dish.  The L band
interference signal is combined with a noise signal using an Anzac H-8-4 combiner. Noise is
generated using a Noise/COM VFX 7112 generator and amplifier chain.  The
noise/interference signal is combined with the DBS desired signal using a second H-8-4
combiner.  Attenuators A and B along with the variable about level capability of the
Noise/COM generator serve to control the relative levels of N and I.  Attenuators C and D
vary the N+I total, relative to the carrier level C.  Bias tees provide DC power for the LNBs
of the two dishes.  A Narda 3 way splitter provides outputs for the Satellite Set-top box,
A-23
Agilent spectrum analyzer, and DBS SAT 9520 Installers Tool.   Note that the pedestal
mounted DBS receive antenna was pointed at clear sky, and the 90 cm dish was used to
collect DIRECTV signals.
A view of the received power spectrum of the transmitted Northpoint MVDDS coupled
into the spillover lobe of the receive dish is shown in Figure A-20.
Figure A-20.  Single Channel MVDDS Open Range Transmission Coupled into
Spillover Region of a DBS Receive Dish
A.8.2  Test Results
Data is recorded at various noise to interference power levels, namely, +infinity, (noise
only), +10 dB, +3 dB, 0 dB, -3 dB, 10 dB, and infinity (interference only).  As in the
previous section, results for +infinity and infinity are plotted on the +30 and 30dB points,
respectively.
Due to lack of time, results were compiled for DIRECTV only and are shown in
Figure A-21.
A-24
The same trend is observed relative to the resilience to the constant envelope QPSK
MVDDS signal as compared to Gaussian noise as was observed in the previous section.  That
is that there is approximately 1 dB resilience to the constant envelope QPSK interference
versus Gaussian interference.
The performance curve given in Figure A-21 sits nearly 1 dB higher in C/(N+I) than the
curve of Figure A-14, the lab 12 GHz measures, and the translated IF measurements of
Figure A-10.  This 1 dB difference is easily accounted for through the combination of
measurement error and DBS transponder bandwidth channelization differences.
Note as well the Proximity of the SAT9520 Measurement in the noise-only case to
spectrum analyzer measurements.  Insufficient information is available about the SAT9520
to provide an accurate scaling factor that would account for differences in measurement
bandwidth between the spectrum analyzer and the SAT9520.
DirecTV C/(N+I) Threshold vs. N/I;
Northpoint Over the Air Interference
3
4
5
6
7
8
9
-30 -20 -10 0 10 20 30
N/I (dB)
C/(N+I) Threshold
Figure A-21.  Carrier-to-Noise-Plus-Interference Required to Degrade DIRECTV to
A/V Quality 6 Vs. Noise-to-Interference Power Ratio; Northpoint MVDDS 12 GHz RF
Output, Open Range
A.8.3  Notes on Open Air Testing
This subsection contains anecdotal notes on some ad-hoc tests that were performed
during the process of antenna installation and measurement.
A-25
A.8.3.1  MVDDS Antenna Azimuth and Elevation
During installation of the MVDDS transmit antenna on the roof of the MITRE facility in
preparation for open range testing, one ad-hoc test was performed for the purpose of
assessing the impact of MVDDS antenna azimuth and elevation on existing DBS
installations.
With the MVDDS antenna pointed due North and 0 degrees elevation, the transmit power
of the antenna was raised to the point of interfering with the DBS installation used for the
laboratory interference measurements discussed in the previous sections, (approximately 300
feet away).  Turning the antenna due east, at 5 degrees elevation, the transmit power was
raised by 13 dB prior to any degradation of the previous installation.
While not intended to be a quantitative test, it is interesting to note that Northpoint
engineers were able to predict and mitigate the impact of the MVDDS transmission on a
nearby installation.
A.8.3.2  Shielding of DBS Antenna as a Means of Interference Mitigation
As alluded to above, the range was configured to maximally couple the MVDDS transmit
energy into any portion of the DBS antenna excluding the main beam.  As suspected from
the antenna gain pattern measurements, maximum coupling occurred when a direct ray from
the MVDDS transmission could be drawn to the LNB of the DBS antenna.
This direct path was blocked by holding a lightweight piece of scrap aluminum between
the MVDDS transmitter and the dish.  We were subsequently able to couple the unattenuated
input from the DBS dish (bypassing attenuator B of Figure A-19) without degrading the AV
quality of the channel under test.  Note that the total power across a 20 MHz bandwidth for
the unattenuated signal at the output of the LNB was 34 dBm, on the same order of
magnitude as the DBS signal.
A.9  Summary of Results
The lab measurements show that the constant amplitude of the MVDDS interference
signal gives it a slight compatibility advantage with the DBS signal as opposed to Gaussian
noise of the same power.  This advantage is on the order of 1 dB when the total interference
is dominated by MVDDS interference.  Results vary slightly between Dish TV and
DIRECTV when the interference and noise are close to the same power.  Any practical
advantage was very difficult to identify when the interference signal power was 3 dB or more
below the noise power for either of the two DBS systems.
Several mitigation techniques were tested:
 When a 7 MHz offset is used by the MVDDS transmission with respect to the DBS
channelization, and additional isolation of approximately 1.2 dB from the DBS signal
A-26
can be achieved due to the spectral mismatch between the victim signal and
interferer.
 Appropriate selection of antenna azimuth and elevation angles was demonstrated to
be effective in mitigating interference in areas close by.  This is perhaps done at the
expense of the MVDDS cell size.
 Blocking of the direct path between an MVDDS transmitter and a DBS dish LNB
proved very effective in mitigating interference.
B-1
Appendix B
Interference Predictions for Selected Scenarios
This appendix contains a series of plots that present contours of constant predicted
interference impact, expressed according to several different criteria, upon populations of
postulated Direct Broadcast Satellite (DBS) receivers dispersed across horizontal planes in
the vicinity of a Multichannel Video Distribution and Data Service (MVDDS) transmitter
located at the origin.  The plots are discussed and interpreted in Section 5.1.2.  As explained
in that section, the plot on page B-3 represents a benchmark scenario, and all the remaining
plots represent excursions from the benchmark case, in which one, two, three, or four
parameters are varied from their benchmark values to determine the sensitivity of the results
to such variations.  The legend beneath each such plot highlights in bold type the parametric
changes that distinguish the scenario in question from the benchmark scenario.
The impact criterion used in most of the plots is the absolute increase ?U caused by
MVDDS in annual rain-induced DBS unavailability U, where U and ?U are both measured
in hours per year (hr/yr).  In those plots the contours are color-coded as follows:
Magenta MVDDS coverage boundary
Blue ?U = 0.3 hr/yr
Green ?U = 1 hr/yr
Red ?U = 3 hr/yr
Cyan ?U = 10 hr/yr
Black ?U = 30 hr/yr
In one plot where the criterion is the relative increase (?U/U
0
) expressed as a percentage,
and U
0
 is the baseline value of U that exists even without MVDDS present, this set of color
codes is used:
Magenta MVDDS coverage boundary
Blue ?U/U
0
 = 2.86%
Green ?U/U
0
 = 10%
Red ?U/U
0
 = 30%
Cyan ?U/U
0
 = 100%
Black ?U/U
0
 = 300%
In the plot where the criterion is the total unavailability (U
0
 + ?U) caused by rain and
MVDDS combined, this color code is employed:
Magenta MVDDS coverage boundary
Blue U
0
 + ?U = 25 hr/yr
Green U
0
 + ?U = 30 hr/yr
B-2
Red U
0
 + ?U = 35 hr/yr
Cyan U
0
 + ?U = 40 hr/yr
Black U
0
 + ?U = 45 hr/yr
Finally, the following color code is used in the single plot whose criterion is (C/I
M
)
0
, the
clear-air value of (C/I
M
), where C is the carrier power and I
M
 is the MVDDS interference
power at the DBS receiver:
Magenta MVDDS coverage boundary
Blue (C/I
M
)
0
 = 25 dB
Green (C/I
M
)
0
 = 20 dB
Red (C/I
M
)
0
 = 15 dB
Cyan (C/I
M
)
0
 = 10 dB
Black (C/I
M
)
0
 = 5 dB
B-3
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz):  benchmark case
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
1.0
  0.3 hr/yr
MVDDS
coverage
boundary
North
?
B-4
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz):  101 W satellite longitude only
Absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for this satellite longitude
Baseline rain-induced unavailability (without MVDDS interference):  2.17 hr/yr
MVDDS
coverage
boundary
Less than 0.3 hr/yr
everywhere
North
?
B-5
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz):  110 W satellite longitude only
Absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for this satellite longitude
Baseline rain-induced unavailability (without MVDDS interference):  3.88 hr/yr
MVDDS
coverage
boundary
0.3 hr/yr
North
?
B-6
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz):  119 W satellite longitude only
Absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for this satellite longitude
Baseline rain-induced unavailability (without MVDDS interference):  24.56 hr/yr
MVDDS
coverage
boundary
1.0
 0.3 hr/yr
North
?
B-7
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz) benchmark case:  region behind transmitter
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
30 hr/yr
North
?
B-8
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum relative increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
10%
2.86%
MVDDS
coverage
boundary
North
?
B-9
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum total DBS unavailability caused by rain and MVDDS combined
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
MVDDS
coverage
boundary
25 hr/yr
North
?
B-10
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Minimum clear-air (C/I
M
) value at DBS receiver
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
MVDDS
coverage
boundary
25 dB
North
?
B-11
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 200 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
MVDDS
coverage
boundary
1.0
 0.3 hr/yr
North
?
B-12
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 400 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
MVDDS
coverage
boundary
 0.3 hr/yr
North
?
B-13
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 50 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
MVDDS
coverage
boundary
1.0
  0.3 hr/yr
North
?
B-14
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 0 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
MVDDS
coverage
boundary
1.0
 0.3 hr/yr
North
?
B-15
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 50 meters below horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
MVDDS
coverage
boundary
1.0
 0.3 hr/yr
North
?
B-16
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 5 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
MVDDS
coverage
boundary
0.3 hr/yr
North
?
B-17
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  7 MHz
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
MVDDS
coverage
boundary
1.0
   0.3 hr/yr
North
?
B-18
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint small sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
MVDDS
coverage
boundary
0.3 hr/yr
North
?
B-19
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  135 azimuth (SE); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
MVDDS
coverage
boundary
1.0
   0.3 hr/yr
North
?
B-20
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  225 azimuth (SW); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
MVDDS
coverage
boundary
1.0
   0.3 hr/yr
North
?
B-21
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  90 azimuth (E); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
MVDDS
coverage
boundary
0.3 hr/yr
             0.3 hr/yr
North
?
0.3 hr/yr
B-22
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  270 azimuth (W); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
MVDDS
coverage
boundary
     0.3 hr/yr
North
?
0.3 hr/yr
B-23
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  000 azimuth (N); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
MVDDS
coverage
boundary
0.3 hr/yr
North
?
B-24
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz):  Detail of region in front of transmitter
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  000 azimuth (N); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
MVDDS
coverage
gaps
0.3 hr/yr
North
?
30 hr/yr
B-25
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz):  Region behind transmitter
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  000 azimuth (N); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
MVDDS
coverage
boundary
0.3 hr/yr
North
?
B-26
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Maximum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 1.95 hr/yr
110 W: 2.62 hr/yr
119 W: 1.73 hr/yr
MVDDS
coverage
boundary
0.3 hr/yr
North
?
B-27
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  0 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
MVDDS
coverage
boundary
1.0
   0.3 hr/yr
North
?
B-28
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  QEF
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 3.43 hr/yr
110 W: 14.37 hr/yr
119 W: 61.96 hr/yr
MVDDS
coverage
boundary
3.0
North
?
1.0
0.3 hr/yr
B-29
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ1
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 1.40 hr/yr
110 W: 3.30 hr/yr
119 W: 11.96 hr/yr
0.3 hr/yr
North
?
B-30
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  24 x 18 single-feed
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.09 hr/yr
110 W: 3.72 hr/yr
119 W: 22.94 hr/yr
MVDDS
coverage
boundary
0.3 hr/yr
North
?
B-31
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  24 x 18 dual-feed
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.69 hr/yr
110 W: 4.90 hr/yr
119 W: 36.55 hr/yr
MVDDS
coverage
boundary
0.3 hr/yr
North
?
0.3
B-32
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.20 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 1.97 hr/yr
110 W: 3.54 hr/yr
119 W: 22.65 hr/yr
MVDDS
coverage
boundary
1.0
  0.3 hr/yr
North
?
B-33
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.70 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.04 hr/yr
110 W: 3.57 hr/yr
119 W: 20.27 hr/yr
MVDDS
coverage
boundary
1.0
 0.3 hr/yr
North
?
B-34
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  -10 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
MVDDS
coverage
boundary
0.3 hr/yr
North
?
B-35
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  -1.5 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
Note:  Maximum MVDDS EIRP for this case is 12.5 dBm.
MVDDS
coverage
boundary
North
?
0.3 hr/yr
1.0
B-36
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  10 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
      10
   3.0
North
?
          1.0
0.3 hr/yr
B-37
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  10 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
radio
horizon
1.0
0.3 hr/yr
North
?
B-38
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  20 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
radio
horizon
0.3 hr/yr
North
?
         10
   3.0
1.0
B-39
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  20 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 200 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
radio
horizon
            10
       3.0
1.0
            0.3 hr/yr
North
?
B-40
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  30 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
radio
horizon
0.3 hr/yr
North
?
3.0
1.0
30
10
B-41
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  30 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 400 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
radio
horizon
1.0
North
?
3.0
10
30
0.3 hr/yr
B-42
Distances in Kilometers from MVDDS Transmitter
Miami, FL (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 8.10 hr/yr
110 W: 17.46 hr/yr
119 W: 57.91 hr/yr
MVDDS
coverage
boundary
1.0
0.3 hr/yr
North
?
B-43
Distances in Kilometers from MVDDS Transmitter
Phoenix, AZ (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.66 hr/yr
110 W: 16.37 hr/yr
119 W: 19.02 hr/yr
Note:  For 119 W only, the second-weakest satellite was considered from this locale.
MVDDS
coverage
boundary
1.0
                  0.3 hr/yr
North
?
B-44
Distances in Kilometers from MVDDS Transmitter
Phoenix, AZ (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  0 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.66 hr/yr
110 W: 16.37 hr/yr
119 W: 19.02 hr/yr
Note:  For 119 W only, the second-weakest satellite was considered from this locale.
MVDDS
coverage
boundary
1.0
              0.3 hr/yr
North
?
B-45
Distances in Kilometers from MVDDS Transmitter
Boston, MA (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.92 hr/yr
110 W: 4.77 hr/yr
119 W: 44.63 hr/yr
MVDDS
coverage
boundary
3.0
North
?
1.0
   0.3 hr/yr
B-46
Distances in Kilometers from MVDDS Transmitter
Chicago, IL (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.89 hr/yr
110 W: 3.07 hr/yr
119 W: 31.33 hr/yr
MVDDS
coverage
boundary
3.0
1.0
0.3 hr/yr
North
?
B-47
Distances in Kilometers from MVDDS Transmitter
Houston, TX (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 4.48 hr/yr
110 W: 11.65 hr/yr
119 W: 36.55 hr/yr
MVDDS
coverage
boundary
1.0
         0.3 hr/yr
North
?
B-48
Distances in Kilometers from MVDDS Transmitter
Los Angeles, CA (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 1.42 hr/yr
110 W: 11.69 hr/yr
119 W: 9.29 hr/yr
Note:  For 119 W only, the second-weakest satellite was considered from this locale.
MVDDS
coverage
boundary
0.3 hr/yr
North
?
B-49
Distances in Kilometers from MVDDS Transmitter
Denver, CO (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 0.79 hr/yr
110 W: 2.22 hr/yr
119 W: 33.25 hr/yr
MVDDS
coverage
boundary
10
       3.0
                   1.0
                 0.3 hr/yr
North
?
B-50
Distances in Kilometers from MVDDS Transmitter
Denver, CO (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  000 azimuth (N); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  7 MHz
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 0.79 hr/yr
110 W: 2.22 hr/yr
119 W: 33.25 hr/yr
MVDDS
coverage
boundary
0.3 hr/yr
North
?
B-51
Distances in Kilometers from MVDDS Transmitter
Denver, CO (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  000 azimuth (N); 0 elevation tilt
MVDDS transmitting antenna 300 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  7 MHz
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 0.79 hr/yr
110 W: 2.22 hr/yr
119 W: 33.25 hr/yr
MVDDS
coverage
boundary
0.3 hr/yr
North
?
B-52
Distances in Kilometers from MVDDS Transmitter
Seattle, WA (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 6.84 hr/yr
110 W: 28.79 hr/yr
119 W: 55.87 hr/yr
MVDDS
coverage
boundary
1.0
0.3 hr/yr
North
?
3.0
B-53
Distances in Kilometers from MVDDS Transmitter
Seattle, WA (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  000 azimuth (N); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  7 MHz
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 6.84 hr/yr
110 W: 28.79 hr/yr
119 W: 55.87 hr/yr
MVDDS
coverage
boundary
0.3 hr/yr
North
?
B-54
Distances in Kilometers from MVDDS Transmitter
Seattle, WA (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  000 azimuth (N); 0 elevation tilt
MVDDS transmitting antenna 300 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  7 MHz
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 6.84 hr/yr
110 W: 28.79 hr/yr
119 W: 55.87 hr/yr
MVDDS
coverage
boundary
0.3 hr/yr
North
?
B-55
Distances in Kilometers from MVDDS Transmitter
Fargo, ND (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Northpoint large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 4.78 hr/yr
110 W: 14.26 hr/yr
119 W: 63.24 hr/yr
MVDDS
coverage
boundary
10
     3.0
              1.0
North
?
0.3 hr/yr
B-56
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Pegasus large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
MVDDS
coverage
boundary
1.0
 0.3 hr/yr
North
?
B-57
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  0 dBm
MVDDS transmitting antenna:  Pegasus small sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
MVDDS
coverage
boundary
North
?
   1.0
0.3 hr/yr
B-58
Distances in Kilometers from MVDDS Transmitter
Washington, DC (12.45 GHz)
Maximum absolute increase caused by MVDDS in rain-induced DBS unavailability
Raw MVDDS transmitter power (not EIRP):  -4 dBm
MVDDS transmitting antenna:  Pegasus large sectoral horn
MVDDS transmitting-antenna boresight:  180 azimuth (S); 0 elevation tilt
MVDDS transmitting antenna 100 meters above horizontal plane
Assumed MVDDS interference scaling factor:  1 dB
Frequency offset between MVDDS and DBS carriers:  none
DBS performance measure:  VQ6
DBS receiving antenna:  18 single-feed dish
Minimum ratio of DBS EIRP to receiver threshold assumed for each satellite longitude
Baseline rain-induced unavailabilities (without MVDDS interference):
101 W: 2.17 hr/yr
110 W: 3.88 hr/yr
119 W: 24.56 hr/yr
Note:  Above coverage boundary assumes G/T = 15.2 dB rather than the usual 11.22 dB.
MVDDS
coverage
boundary
0.3 hr/yr
North
?
GL-1
Glossary
AM amplitude modulation
AUT antenna under test
A/V audiovisual
AWGN additive White Gaussian noise
AWS arbitrary waveform synthesizer
BER bit error rate
BW bandwidth
C/N carrier to noise ratio
C/N + I carrier to noise plus interference ratio
dB decibel
dBi db referenced to the gain of an isotropic antenna
dBil dBi linear
dBic dBi circular
DBS Direct Broadcast Satellite
EIRP effective isotropically radiated power
FCC Federal Communications Commission
FY Fiscal Year
GHz gigahertz
hr/yr hours per year
IF intermediate frequency
IMUX input multiplexer
ITU International Telecommunications Union
km kilometer
LHCP left-hand circular polarization
LNB low noise block converter
MHz megahertz
MPEG Motion Picture Experts Group
GL-2
MVDDS Multichannel Video Distribution and Data Service
NPRM Notice of Proposed Rulemaking
NSI Nearfield Systems Incorporated
OMUX output multiplexer
PFD power flux density
PM phase modulation
QEF quasi-error free
QPSK quadrature phase shift keying
RHCP right-hand circular polarization
RMS root mean square
R&O Report and Order
SMA sub-miniature A
SPW? Signal Processing Workstation
TWT traveling wave tube
TWTA TWT amplifier
U.S. United States