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Autotune update proposal

Autotune update proposal. GS: Sends XID_CMD_HO (P=0) AC accepting the request: “If the AC LME receives the XID-CMD-HO (P=0) , it shall commence an AC initiated handoff to a ground station ( XID_CMD_HO (P=1) ) , preferably one listed in the Replacement Ground Station List parameter.”

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Autotune update proposal

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  1. Autotune update proposal

  2. GS: Sends XID_CMD_HO (P=0) AC accepting the request: “If the AC LME receives the XID-CMD-HO (P=0), it shall commence an AC initiated handoff to a ground station ( XID_CMD_HO (P=1) ), preferably one listed in the Replacement Ground Station List parameter.” AC rejecting the request: “If the AC LME cannot initiate the handoff, it shall send an XID-CMD-LCR (P=0); the current link shall not be affected.” Retransmission: AC “shall only transmit the XID-CMD-HO(P = 1) once per received XID-CMD-HO (P=0)” GS: Sends XID_CMD_HO (P=0) AC accepting the request: “If the AC LME receives the XID-CMD-HO (P=0), it shall commence an AC initiated handoff to a ground station ( XID_CMD_HO (P=1) ), preferably one listed in the Replacement Ground Station List parameter.” AC rejecting the request: “If the AC LME cannot initiate the handoff, it shall send an XID-CMD-LCR (P=0); the current link shall not be affected.” Retransmission: “the AC LME shall retransmit on the new frequency the XID-CMD-HO (P=1) using the normal retransmission procedures” Current GRAIHO Description in VDL Tech Manual: Without Autotune With Autotune

  3. Existing Issues (1/2) Disconnection of air/ground link during autotune processing by aircraft is not clearly specified The aircraft ends up handing off a link that really doesn’t exist. Disconnection is needed due to lack of ability to communicate on old link due to retuning of aircraft radio Current standards only has provision for destruction of old link due to TG5 expiration Lack of knowledge in the ground system as to what state the aircraft is in during the GRAIHO procedure. There is no notification to the ground that the aircraft is retuning, simply a notification if the aircraft will not retune. There is no way to determine if the aircraft is performing the operation or simply has not understood or heard the request. This leads to the ground needing to retransmit the GRAIHO (or other INFO frames) until TG5 expires on the old ground station (or the new GS notifies the old GS of the new link). Ground system does not know which aircraft are capable of being frequency managed Overly complicated procedures – No need seen for: XID_RSP_LE and XID_RSP_HO to include autotune parameter Use of GRAIHO to support single frequency link management Page 3

  4. Retransmission procedures for ground requests unclear and internally inconsistent Tech Manual Section 5.3.4.3: XID_CMDs(except for ground station information frames) shall be retransmitted using the procedures defined in 5.3.4.1. Tech Manual Section 5.3.9: The originator of an XID_CMD (P=1) frame shall retransmit the XID upon expiration of Timer T3 whenever no response has been received. 5.3.4.3 states to use T3 for all handoffs, 5.3.9 states to use T3 only for P=1. Procedures for GIHO and GRAIHO interaction need to be clarified It is undefined how an aircraft will react if processing a GRAIHO and it receives a GIHO Existing Issues (2/2)

  5. Proposed Updates • Replace GRAIHO with GRAILE • Frequency change procedure: • AC shall explicitly disconnect old link • This avoids potentially retransmitting GRAILE when aircraft has changed frequencies. • AC LME shall tune AC radio to new frequency • AC shall send Air-Initiated Link Establishment XID: XID_CMD_LE (P=1) on the new frequency • This clarifies and documents existing and proposed procedures • Add capability bit to AVLC specific options parameter to indicate aircraft support of GRAILE procedures • Removal of autotune parameter from XID_RSP_LE and XID_RSP_HO • Mandate inclusion of autotune in GRAILE • Timer T3 operation • Standardize on using T3 for all XID_CMDs • GIHO should take precedence over an ongoing GRAILE procedure

  6. Proposed Changes to VDL Tech Manual

  7. Proposed Changes to VDL Tech Manual (cont.) Current Table 5-12. Abbreviate XID names New

  8. Proposed Changes to VDL Tech Manual (cont.)

  9. Proposed Changes to VDL Tech Manual (cont.)

  10. Proposed Changes to VDL Tech Manual (cont.)

  11. Proposed Changes to VDL Tech Manual (cont.)

  12. Proposed Changes to VDL Tech Manual (cont.)

  13. Proposed Changes to VDL Tech Manual (cont.)

  14. Further work to be incorporated Determine if there is there a way to maintain the MSNDCF context if the aircraft sends a disconnect to the ground. Differentiate P=1/0 between editorial and substantive changes Review backwards-compatibility of each proposed change GRAI -LE vs –HO Ground receipt of DISC General backwards-compatibility issues with standard AVLC specific options code A/G version mismatch Unknown parameter values Page 14

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