MSS Interference Analysis for AeroMACS

October 12, 2012

Introduction

Working group was established by RTCA SC-223

Charter:

“Define a working method of specifying emissions from all expected AeroMACS future deployments that are compliant with ITU co-interference requirements, to establish 2-way link levels with the aircraft to ensure closure of the RF-link without adversely affecting the Global Star Satellite feeder links. The deliverable would be in the form of MOPS or SARPS requirements and a technical report delivered to an ICAO technical group via a working paper.”

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MSS Interference Analysis WG Participants

FAA - Brent PhillipsFAA - Mike Biggs

DFS - Armin SchlerethECTL - Nikos Fistas INDRA – Antonio Correas UsonSINTE - Jan Eric Hakegard NASA - Jeff WilsonNASA - Rafael Apaza

Harris - Art Ahrens

ITT Exelis - Bruce EcksteinITT Exelis - Natalie Zelkin ITT Exelis – Ward Hall

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Analysis Method

• Very large and Large size airports> US categories: XL/Large/OEP (Qty 35)> Europe categories: Very Large/Large (Qty

50)> Model parameters

> Horizon-omni base station pattern> 2x transmitter PA power> All AeroMACS channels* are used

• Medium size airportsUS category: Class C (Qty 123)> Europe category: Medium (Qty 50)> Model parameters

> Horizon-omni base station pattern> 1x transmitter PA power> AeroMACS channel use factor

• Small size airports> All other airports in Openflights database.> Model parameters

> Base station sector directional antennas> Sectors pointed in random directions> 1x transmitter PA power> AeroMACS channel use factor

• All airports world-wide are included in the analysis

> Non-US and Europe airports found to not to contribute significantly to N. Atlantic interference “hotspot”

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The analysis method was driven by the European study [1] of number of sectors required at an airport (e.g., if the number of sectors was greater than 11 (number of channels in 5091-5150) then a “pseudo-omni was assumed as a given channel would be used in more than one direction)

[1] WA4 Airport Capacity & Coverage

•An AeroMACS “channel” is the 5 MHz-wide bandwidthtransmitted by a base station sector that consists of 512 sub-carriers

Analysis Conditions and Assumptions

• Effective isotropic Radiated Power (EiRP) is the sector transmit power at the antenna input plus antenna gain

• Maximum allowable EiRP in a base station sector shall be the sum of both transmit power amplifiers (PA’s) in a 2-channel MIMO system

• Base Station Sector patterns are defined to be ITU-R F-1336-2 reference patterns with 120˚ 3dB beamwidth toward the Horizon

• Zero base station pattern down-tilt• Scaling assumptions:

> A factor for occupied number of channels per airport category> 22 channels used for large airports> 6 of 11 channels for medium airports> 1 of 11 channels for small airports

> Apply a 50% power reduction to small airports

• MSS interference analysis completed by NASA using Visualyze software

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Recommendedgain mask

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Draft Limits Table

Airport Category Definitions – Based on ICAO airspace definitions

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Airport category

Maximum number of channels at an airport

Maximum total radiated power at an airport channel, mW

Maximum Allowable EiRP per Base Station Sector, dBm• +22 dBm (300 mw) maximum sector PA power• +15 dBi peak sector antenna gain

0˚ (Horizon) to +1.5˚ Elev.

+1.5˚ to 7.5˚(linear decrease)

+7.5˚ to 27.5˚(linear decrease)

+27.5˚ to Zenith(linear decrease)

Large 66 1800 37 37 to 34 34 to 22 22 to -1Medium 18 900 37 37 to 34 34 to 22 22 to -1

Small 1 150 34 34 to 31 31 to 19 19 to -4

Recommendations

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The ACP WG is invited to consider using the provided information as the basis of ICAO SARPs spectrum requirements for AeroMACS.