Download - Key Technical Provisions of the White Paper and Protections Afforded to ITFS Licensees. National ITFS Association Annual Conference February 16 th – 19

Key Technical Provisions of the White Paper and Protections Afforded to ITFS Licensees.

National ITFS Association Annual ConferenceFebruary 16th – 19th, 2004Fort Lauderdale FLHarry Perlow

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Table of Contents

• The Mid Band Segment•Interference Mitigation

• Downconverters• NTSC Video and Guard Bands• Frequencies and Interference• Spectral Masks

•Rule Changes in the MBS• Part 74.x

•Conclusions

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Interference Mitigation - MBS

What are the issues? • Brute Force Overload (BFO).

• From Cellular Operations to ITFS Receive Sites.

• Out of Band Emissions (OOBE). • From Cellular Operations to ITFS Receive

Sites.

Flexible Use

2500 2566 2620

High Power Operations

2572 2614

Flexible Use

2686

I Ban

d

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Brute Force Overload• ITFS Receive Sites in proximity to Cellular Base

Stations must not be allowed to receive high amplitude signals from the LBS and UBS.

• Unable to predict the locations of future receive sites.

• Can design around existing ITFS receive sites.

High Power Operations42 MHz

GUARD

A4 B4C4 D4 E4 F4 G4

GUARD

Flexible Use Flexible Use

I Ban

d

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MBS Downconverters • Filters are built-in.

• Attenuate signals from the LBS and UBS.• Guard Bands are sufficient to allow filters to be

effective.• Higher Output Capability – IP3.• Prevents Brute Force Overload !!!


GUARD

A4 B4C4 D4 E4 F4 G4

GUARD

Flexible Use Flexible Use

I Ban

d

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NTSC Video • Power Spectral Density varies across bandwidth

and decreases rapidly away from Video Carrier. • Interference becomes increasingly perceptible.• Undesired signals can “mix” in TV tuner.

Color Sound3.58 MHz 4.5 MHz

Video1.25 MHz

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NTSC Video • Power Spectral Density varies across bandwidth

and decreases rapidly away from Video Carrier. • Interference becomes increasingly perceptible.• Undesired signals can “mix” in TV tuner.

Color Sound3.58 MHz 4.5 MHz

Video1.25 MHz

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Guard Bands • Provide for 6 MHz separation in the MBS.• Signals that are not NTSC, are high in

amplitude and less than 6 MHz away from an NTSC Analog Video signal will cause destructive interference.


GUARD

A4 B4C4 D4 E4 F4 G4

GUARD

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Frequencies and Co Channel Interference• NTSC Analog Video signals – Unequal

spectral density and peak power at visual carrier.

• All NTSC Visual Carrier Frequencies must be the same in every market !!!

• MBS must be the same size everywhere !!!

A4 B4 C4 D4 E4 F4 G4

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Spectral Masks• Out of Band Emissions from the LBS and

UBS are In-band or co-channel to the MBS.• The Downconverter cannot do a thing

about it.• OOBE from Base Stations in the LBS and

UBS will protect the MBS Noise Floor.

A4 B4 C4JLower Band SegmentLower Band Segment

J

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Spectral Masks• Handsets and CPE OOBE must also protect the MBS.• 67 + 10 Log (p) = -37 dBm• Free space loss for 100 feet at 2600 MHz = - 70.44 dB• The total = -107.44 dBm which 6 dB + below

the noise floor.

A4 B4 C4JLower Band Segment

43 + 10 Log (p)

At Block Edge 55 + 10 Log (p)

5.5 MHz Away 67 + 10 Log

(p) In any MBS Channel

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A word about Spectral Masks….• X +10 Log (P) Masks are an absolute value.• An absolute value represents an absolute

distance at an absolute frequency.• Interference prediction is then absolute !!!

A4 B4 C4JLower Band Segment

43 + 10 Log (p)

At Block Edge 55 + 10 Log (p)

5.5 MHz Away 67 + 10 Log

(p) In any MBS Channel

Proposed Technical Rule Changes in the MBS

Streamlining Part 74.x

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Streamlining Part 74.x• For analog transmissions, 45 dB co-channel

D/U ratio should be maintained.• For digital transmissions, 32 dB D/U ratio

should be allowed. • Based on 26 dB requirement for 64 QAM.

• Relaxed co-channel D/U ratio for precise frequency offset analog operations at 38 dB.

• If utilized transmitters must have + or - 10,010 precision frequency offset with + or - 3 Hz stability.

• If PSAs Overlap, the “football” formed is split.• Interference calculations will only be done at

points within a PSA/GSA that receive a desired signal level of -80 dBm or greater in a 6 MHz bandwidth or equivalent.

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Streamlining Part 74.x• The undesired signal must be above –106.2

dBm to be considered interference in a 6 MHz bandwidth or equivalent.

• Adopt a “di minimis” interference exception of no more than 0.5 % of the GSA area.

• Border protection of -73 dBW/m2 at the Grandfathered MBS PSA boundary.

• §74.903 (2) Adjacent Channel of –10 dB has been proposed.

• Desired signal is calculated using 4/3 earth curvature terrain – sensitive propagation model.

• Cross Polarization –26 dB rather than – 20dB.

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Streamlining Part 74.x• MBS OOBE – Unchanged but filters may be

upgraded by the LBS and UBS operators.• No more than 100 nanoseconds delay – analog.• No more than 20 nanoseconds delay – digital.

• Equipment upgrades – Continued allowance for antenna upgrades subject to zoning, structural and environmental restrictions.

• Upstream operations in the MBS channels must have written consent from all other licensees in the 2.5 to 2.7 GHz band within 150 miles.

• Licensees who operate in the MBS in a upstream manner must accept interference from those downstream operations in the MBS.

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Conclusions

• High Power, High Site systems can co-exist with Low Site Cellular Architecture with:

• The Coalition’s Band Plan;• Properly Engineered MBS Downconverters; • Proposed protection from Out of Band

Emissions.• Future ITFS Receive Sites are protected.• PSA to GSA overlap solution enables “no mans land” to finally be served.

• Part 74.x of the Rules for the MBS has been streamlined and now makes sense.

Download - Key Technical Provisions of the White Paper and Protections Afforded to ITFS Licensees. National ITFS Association Annual Conference February 16 th – 19

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