1. MSS Interference Analysis for AeroMACS
October 12, 2012

2. 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.”

3. MSS Interference Analysis WG Participants
FAA - Brent Phillips FAA - Mike Biggs DFS - Armin Schlereth ECTL - Nikos Fistas INDRA – Antonio Correas Uson SINTE - Jan Eric Hakegard NASA - Jeff Wilson NASA - Rafael Apaza Harris - Art Ahrens ITT Exelis - Bruce Eckstein ITT Exelis - Natalie Zelkin ITT Exelis – Ward Hall

4. 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 airports
US category: Class C (Qty 123)
Europe category: Medium (Qty 50)
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”
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
) 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 bandwidth transmitted by a base station sector that consists of 512
sub-carriers

5. 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 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

6. Recommended gain mask

8. Maximum number of channels at an airport
Draft Limits Table
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˚
+27.5˚ to Zenith
Large 66
1800 37
37 to 34
34 to 22
22 to -1
Medium 18
900
Small 1
150 34
34 to 31
31 to 19
19 to -4
Airport Category Definitions – Based on ICAO airspace definitions

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