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AERONAUTICAL COMMUNICATIONS PANEL (ACP) SEVENTEENTH MEETING OF THE WORKING GROUP M Bangkok, Thailand 31 January – 1 February 2011 INFORMATION PAPER Uplink Broadcast SNDCF. R. Morgenstern, MITRE. Statement of Problem. Point-to-point communications inefficient for some messaging
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AERONAUTICAL COMMUNICATIONS PANEL (ACP)SEVENTEENTH MEETING OF THE WORKING GROUP MBangkok, Thailand 31 January – 1 February 2011INFORMATION PAPERUplink Broadcast SNDCF R. Morgenstern, MITRE
Statement of Problem • Point-to-point communications inefficient for some messaging • D-ATIS in the vicinity of the airport • SIGMET • NOTAMs • Aircraft Microphone Check (AMC) • AEEC DLK providing broadcast capability for AOA similar to POA network • It could be beneficial if solution included ATN interface
Broadcast scope • All aircraft for a particular Ground Station • All aircraft for a cluster of Ground Stations • All aircraft of a particular airline • A subfleet of a particular airline
Proposed AOA Implementation • For AOA ground station addressing, use AP or GL TEIs to address a pre-defined GS or cluster of GSs • E.g., AP AL10, AP IAD1 • For AOA addressing, use existing A620/618 AN/FI TEIs to address user fleet/subfleets • E.g., AN AL-B737/FI AL9999, AN BA-XXXX/FI BA9999 • No acknowledgement to broadcast messages • Duplication detection based on UBI • Generate new UBI for each unique uplink broadcast • Use same UBI for broadcasts over more than 1 GS • Only one ACARS uplink sent per GS • No uplink ACARS timers (GT1, GT2) • Limited to one ACARS block
Proposed ATN Implementation • Reconstitute CLTP in ICAO Doc 9880, Part III • Utilize destination NSAP to identify scope of broadcast • Routers would need to recognize address and realize it might need to multicast to reach all relevant GSs • E.g., ARS = 0xFFFFFFh and accept all LOC/SYS fields • Create Broadcast SNDCF to bypass current Mobile 8208 sublayer
ATN NSAP Addressing • For CLNP addressing, use 0xFFFFFF for ARS • Then LOC can determine the scope of the broadcast • And SYS can determine the specific GS, cluster, airline and/or airline subfleet • SEL = 02h consistent with AsiaPac use to indicate ISO 8602 CLTP ground or air ES
Possible LOC/SYS Encoding • LOC • 0000h reserved • 0001h Single GS • SYS = unique GS identifier, such as SiteID/RadioID • 0002h Airport • SYS = 0000h + 4character Airport Code • 0003h ACC/TRACON • SYS = FFFFFFh + 3character facility code (e.g., “ZTL”) • SYS = sectorID + 3character facility code (e.g, “N90”) • 0004h-FFFEh reserved • FFFFh All GS in ADM region/country • SYS = FFFFFFFFFFFFh
VDL Mode 2 Interfacing • Use UI frame in AVLC • Use IPI/EIPI to identify destination applications and bypass 8208 sublayer • AOA continues to use current 0xFFh • ATN: • CPDLC (AMC, Advisories), FIS, ADS-C, AOC/FOC • ARINC750 radio implementations limited to only 3 addresses stored, so can’t use AVLC addressing to isolate sub-sets of a ground station’s coverage • AOA has means to provide filtering based on A620/618 address • For ATN, addition of a Broadcast Scope field following the IPI/EIPI is possible • Alternately, just pass all to CLNP and let it filter
Status • AEEC DLK proceeding with AOA broadcast capability to support AOC needs • FAA has action to document need for broadcast capability to RTCA SC214/EUROCAE WG78 • Coordination with WG92 when it is started • LINK2000 already experiencing some D-ATIS-related congestion • AMC application can overload channel for large/busy airports depending on scope of use