Outcome of Web meeting Draft Manual as at end of Day 2 V2

2.11.10 User and BS characterization

2.11.10.1 This section defines the average and maximum application level bitrate generated in DL and UL directions per type of user that can be found at the airport, and the maximum bitrate supported by a BS giving access to such users to the AeroMACS access network.

ASSUMPTION: The user typology is defined in line with the AeroMACS Manual [2] where a list of devices classes is defined. This document defines the following device configurations of MS to work out a classification of the types of services to be provisioned, number of connections and data rates, however it is acknowledged that these would differ on a case by case basis.

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  Aircraft at the gate - represents modems installed in aircraft. Considering both safety and non-safety applications all identified types of connections are recommended for aircraft except video. The aircraft is at the gate and executing the pre-departure and post-arrival applications necessary for the turnaround process.
  
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  Aircraft at hangar, taxiway or runway – same as above but the aircraft is executing turnaround processes at the ground movement area or maintenance operations.
  
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  Surface vehicle – represents devices hosted on all ground support vehicles including passenger vans/buses, dollies carrying cargo, refuel trucks, catering vehicles and Push back tugs/ tractors etc., Generally, most of these vehicles are equipped with PTT phones. In addition, A-SMGCS (Advanced Surface Movement Guidance & Control System) may require a safety link for exchanging vehicle’s position information on a periodic basis to a centralized control system.
  
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  Video Sensor – shall be used for sending videos during emergency situations.
  
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  Ground critical – represents devices used to monitor/control ground equipment that are deployed for critical ATS services. Example: Landing Systems, Runway Lighting controls etc.
  
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  Ground Default – All other ground equipment fall under this default category.
  

ASSUMPTION: Table 1 provides the average and peak throughput requirements at the application level for each of these types of user. The bitrate for aircraft is based on the AeroMACS MASPS [3], the rest are assumed based on expected application load and video/audio codec configuration.

	Average ^0 application bitrate		Peak ^0 application bitrate
	FL (GS->MS)	RL (MS->GS)	FL (GS->MS)	RL (MS->GS)
Aircraft at gate^0	150 kbps	150 kbps	600 kbps	300 kbps
Aircraft at hangar, taxiway or runway^3	20 kbps	40 kbps	40 kbps	100 kbps
Surface vehicle	8 kbps	10 kbps	16 kbps	20 kbps
Video sensor^0	1 kbps	64 kbps	4 kbps	512 kbps
Ground critical	1 kbps	1 kbps	4 kbps	8 kbps
Ground default	1 kbps	1 kbps	4 kbps	4 kbps

Table 1. Device classes

2.11.10.2 In order to calculate the throughput limitations in a BS, the modulation/coding rate and the DL/UL OFDM symbol ratio needs to be derived. Table 2a depicts the [3] calculation of the application data rate (TCP/IP PDU throughput) in a BS depending on the modulation/coding scheme used. Note that these results were obtained by applying (32,15) DL/UL OFDM symbol rate. The rate (26,21) is also considered in this study as the most symmetrical DL/UL configuration mandated in the profile (ICAO). The throughput resulting from this configuration is approximated in Table 2b.

Table 2a. AeroMACS expected TCP/IP throughputs vs modulation schemes for DL/UL OFDM symbol rate (32,15)

MC scheme	Downlink [kbps]	Uplink [kbps]
QPSK ½	824.7	698.77
16QAM ½	1806.18	1621.62
64QAM ½^0	3015.19	2308

Table 2b. AeroMACS expected TCP/IP throughputs vs modulation schemes for DL/UL OFDM symbol rate (26,21)
2.11.10.3 Two types of BS are identified depending on their position and expected coverage:

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  Micro-cell BS is placed at the gate and gives mainly high-capacity to aircraft and other devices at the ramp area with a limited service range (covering about 3-5 gates). ASSUMPTION: 75% of the users are within range to be serviced by 64QAM ½ and the rest by 16QAM ½.
  
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  Macro-cell BS is placed around the airport surface and gives high-range coverage to most of the airport surface areas. Table 3 shows the result of the total supported throughput in both directions with the proportion of modulation/coding rates used. ASSUMPTION: 20% of the users are within range to be serviced by 64QAM ½, 40% by 16QAM ½ and 40% by QPSK ½.
  

	Modulation/code scheme	Supported throughput FL/RL (Mbps) at (32, 15) DL/UL rate	Supported throughput FL/RL (Mbps) at (26, 21) DL/UL rate
Micro-cell BS	64QAM ½ (75% users) 16QAM ½ (25% users)	3.3/1.7	2.7/2.1
Macro-cell BS	64QAM ½ (20% users) 16QAM ½ (40% users) QPSK ½ (40% users)	2/1	1.7/1.4

Table 3. BS types and maximum throughput