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

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2.7.1.4 Ethernet Specific Part
2.7.1.4.1 In this configuration Ethernet is supported as the higher layer for AeroMACS. Ethernet packets are received at the CS SAP interface, which are then classified as per the classification rules, header suppression applied if PHS rules are defined and scheduled for transmission as per the QoS policies defined for the service flow. Classification shall be based on Ethernet Header information, IP Header Information in case of IP over Ethernet and/or VLAN Header information.
2.7.1.4.2 Robust Header Compression (ROHC) shall also be applied in addition to PHS to compress IP Header Portions in addition to Ethernet Header compression. ROHC operations shall be performed in accordance with RFC 3095, RFC3759, RFC 3243, RFC 4995, RFC 3843, RFC 4996.

The figure below shows a typical AeroMACS configuration for Layer2 operations.

Figure – CS 5 Ethernet CS
2.7.1.4.3 In this configuration BS and SS act as layer 2 devices forwarding the Ethernet packets to the other side. GRE tunnels are established between BS and ASN Gateway to extend the AeroMACS connections established between SS and BS. In this configuration SS does not perform any functions related Layer 3 (IP) related functions such as DHCP negotiations or IP address configurations. Such functionalities are to be handled by the aircraft edge router connected to SS. Basically, IP link is established between aircraft router and ASN gateway.

2.7.1.5 IP Specific Part

2.7.1.5.1 In this configuration IP packets are directly carried over AeroMACS link. Classification is based on IP Header Information. ROHC can also be used instead of PHS. The figure below shows IP CS configuration.

Figure – CS 6 IP CS

2.7.1.5.2 In this configuration, SS acts as the edge IP router as well. Therefore it establishes both Layer 2 and Layer 3 connectivity with ASN Gateway. Hence SS is responsible for negotiating IP addresses with ASN Gateway and creating IP interface towards ASN GW.

2.8 System management
2.8.1 Network management services are used to establish and maintain connections between each pair of subscriber and ground systems in the AeroMACS network. These services are called NET in terms of service classification and prioritization. They include network connection and network keep-alive services and can include other performance monitoring and supervision services.”

2.8.2 Performance Management
2.8.2.1 Performance monitoring consists in the collection of reliable statistics of the quality of datalink communications between subscribers and ground systems within the AeroMACS network. These statistics can be collected over different timescales, including system (e.g. dropped call statistics, BS loading conditions, channel occupancy, RSSI), user (e.g. terminal capabilities, mobility statistics), flow, packet, etc. The statistics are used by the AeroMACS ground system or component operator to detect datalink events that cause the communication service to no longer meet the requirements for the intended function. The ground system must also support notification capability in order to enable System Supervision. The monitoring capability must not impede the normal operation of the AeroMACS network.”
2.8.2.2 System Supervision
2.8.2.2.1 System supervision capability is intended for the AeroMACS network operator to disseminate information concerning identified problems in the AeroMACS network to operators and ATS providers to raise awareness and facilitate problem resolution. The recommended solution is to use VLANs for network segregation, including one VLAN dedicated to management/supervision purposes (separated from user data traffic) on the BSs, and a VPN over such management VLAN used for remote access by an administrator to the BS for configuration, management and supervision purposes.

2.8.2.2.2 The recommended management protocol is SNMP in order to give the operator of the network the means to supervise the status and receive problem reports from the elements of the AeroMACS system and easily trace back to the point the problem was encountered by the protocol. It is recommended that MSs, BSs and ASN-GW implement SNMP agents, and that the network architecture integrates a management information base (MIB)”.

2.9 FREQUENCY ALLOCATION AND CHANNELIZATION
2.9.1 AeroMACS operates in frequency bands allocated – either on a national or international basis – to the aeronautical mobile (route) service (AM(R)S). As a result, AeroMACS is restricted to supporting communications related to safety and regularity of flight. In addition, in accordance with International Telecommunications Union (ITU) Radio Regulations, AeroMACS is limited to supporting surface applications transmissions at airports.
2.9.2 By definition communications in the AM(R)S are limited to being between aircraft and ground stations, or between aircraft. In ITU however the precedent exists that local area networks (like AeroMACS) operating in frequency bands allocated to a mobile service (like AM(R)S) can support both mobile and fixed/nomadic (i.e., low mobility) applications. As a result, some States plan to utilize AeroMACS also for airport surface communications between ground stations. Finally, some States allow limited use of AM(R)S frequency bands (and by extension AeroMACS) by non-aircraft vehicles; in particular vehicles such as snow ploughs which may mix with aircraft on the airport movement area.
2.9.3 AeroMACS equipment can tune across the band 5000 MHz to 5150MHz, in 250 kHz steps with reference channel of 5145 MHz. That reference channel is used to identify a channel whose center frequency is included in the list of center frequencies that are to be tuned by AeroMACS, and it is a reference point for the identification of all other center frequencies that may be tuned by AeroMACS using the channel step size. The 250 kHz step size will allow AeroMACS to gracefully move away from any interference source such as microwave landing systems (MLS), Aeronautical Mobile Telemetry (AMT), or Military users operating in the 5000-5150 MHz band.
2.9.4 The core or primary AeroMACS band is 5091-5150 MHz, however channels can also be assigned in the sub-bands 5000-5030 MHz based on national regulations, and 5030-5091 MHz depending on frequency planning defined at ICAO level considering other Aeronautical applications.
2.9.5 Due to its limitation to surface transmissions, it is expected that in most cases all AeroMACS channels will be available at all airports (i.e., airport-to-airport coordination is not expected to be necessary). It is also expected however that not all airports will have sufficient communications requirements to necessitate use of all the AeroMACS channels.
2.9.6 One constraint on AeroMACS that was considered during the development of the AeroMACS standards is ensuring compatibility with satellites that share the operating frequency band. While those standards were developed using worst-case assumptions, compatibility with the satellites can be enhanced by, for airports which do not require use of all the channels, distributing actually-assigned channels across the band. In order to ensure uniformity in that distribution, it is expected that a central authority in each State will control AeroMACS assignments.
2.9.7 Further detail on AeroMACS channel assignment criteria and constraints are under development by ICAO. When completed they will be included in Annex 10 Volume V.
2.9.8 AeroMACS is for communication on the airport surface only. Although aircraft on the approach and departure phase of the flight may receive AeroMACS signals while on flight as shown by the glide slopes in Figure 1, aircraft is not permitted to transmit one AeroMACS bands while in flight. Airport systems should be designed to reduce sky-ward emissions through appropriate placement and orientation of the AeroMACS antennas.




2.10    IMPLEMENTATION
2.10.1    Base Station/Subscriber Station Siting Criteria