SIST EN 301 841-2 V1.1.1:2006

• Abstract:

  The present document applies to VDL Mode 2 ground-air digital communications using Differential Eight Phase Shift Keying (D8PSK), intended for channel increments of 25 kHz. The VDL Mode 2 system provides data communication exchanges between aircraft and ground-based systems. The scope of the present document is limited to ground-based stations. The VDL Mode 2 system is designed to be a Ground/Air sub-system of the Aeronautical Telecommunication Network (ATN) using the AM(R)S band and it is organized according to the Open Systems Interconnection (OSI) model (defined by ISO). It shall provide reliable subnetwork services to the ATN system. The present document provides functional specifications for ground-based radio equipment intended to be used for ground-air data communications. The present document is derived from the following documents:; • VDL Mode 2 SARPs version 3.0. ICAO Annex 10 Volume III part I [1].; • ED 92a [2]: "MOPS for an Airborne VDL Mode-2 Transceiver Operating in the frequency range 118-136.975 MHz" (2003), which specifies the airborne transceiver.; The present document consists of two parts:; • the first part provides functional specifications and test procedures for physical layer and MAC sub-layer;; • the second part provides functional specifications and test procedures for link and sub-network access layers.

• Status: Published
• Publication Date: 28-Feb-2006
• ICS: 33.060.99 - Other equipment for radiocommunications
• ICS: 33.100.01 - Electromagnetic compatibility in general
• Technical Committee: SS EIT - Technical Board for the electrotechnical, information technology and telecommunications fields
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Mar-2006
• Due Date: 01-Mar-2006
• Completion Date: 01-Mar-2006
• Mandate: M/239
• Ref Project: ETSI EN 301 841-2 V1.1.1 (2004-03) - Electromagnetic compatibility and Radio spectrum Matters (ERM); VHF air-ground Digital Link (VDL) Mode 2; Technical characteristics and methods of measurement for ground-based equipment; Part 2: Upper layers

Overview

SIST EN 301 841-2 V1.1.1:2006 is a Slovenian standard that specifies the upper layer technical characteristics and measurement methods for ground-based equipment operating within the VHF air-ground Digital Link (VDL) Mode 2 system. The standard ensures that ground stations involved in ground-air digital communications for civil aviation meet international requirements for electromagnetic compatibility and radio spectrum efficiency.

This part of the standard is focused on the upper layers of the VDL Mode 2 protocol stack, in line with the Open Systems Interconnection (OSI) model, and is integral to the effective operation of the Aeronautical Telecommunication Network (ATN) using the Aeronautical Mobile (Route) Service [AM(R)S] band. It defines processes and functions that enable ground-air data communication between aircraft and ground-based systems, aiming at increased reliability, interoperability, and regulatory compliance.

Key Topics

• VDL Mode 2 Protocol Structure: Organization of network communication following the OSI model, focusing on link and subnetwork access layers for ground-ground and air-ground connectivity.
• Electromagnetic Compatibility (EMC): Requirements ensuring that equipment operates without causing or suffering from electromagnetic interference.
• Radio Spectrum Matters (ERM): Efficient and compliant use of designated VHF frequencies (25 kHz channel increments) for safe aeronautical communication.
• Data Link Layer Specifications: Processes and procedures covering data transfer, error detection, addressing schemes, and frame management.
• Link Management and Handover: Procedures allowing continuous connectivity during aircraft station hand-offs and network transitions.
• Testing and Measurement: Standardized methods for performance verification and protocol compliance of ground-based VDL Mode 2 equipment.

Applications

The SIST EN 301 841-2 V1.1.1:2006 standard is critical for various stakeholders in the field of aeronautical communications, providing practical benefits such as:

• Air Traffic Management (ATM): Enhances safety and efficiency of airspace by supporting reliable ground-air data exchanges.
• Ground Station Implementation: Guides manufacturers and operators on building compliant VDL Mode 2 ground equipment that integrates successfully into the wider network.
• Interoperability: Ensures seamless data communication between ground systems and a diverse fleet of aircraft, aligned with International Civil Aviation Organization (ICAO) and Eurocontrol strategies.
• Regulatory Compliance: Helps organizations meet European and international regulations for radio spectrum management and electromagnetic compatibility.
• Testing Laboratories: Provides measurement methods for validating equipment functionality against operational and safety standards.

Related Standards

Organizations seeking full compliance and interoperability should consider the following related specifications:

• SIST EN 301 841-1: Covers lower layers (physical and MAC sublayer) for VDL Mode 2 ground-based equipment.
• ICAO Annex 10 Volume III, Part I: International standards and recommended practices for aeronautical telecommunications systems.
• EUROCAE ED-92a: Minimum Operational Performance Specification for airborne VDL Mode 2 transceivers.
• ISO OSI Model Standards: Foundational references for layered network communications.
• EN 301 489 series: General EMC requirements for radio equipment.

Adhering to SIST EN 301 841-2 V1.1.1:2006 ensures that ground-based VHF digital communication systems are robust, interoperable, and ready to meet evolving aviation communication demands. This standard is essential for ensuring safe, efficient, and future-proofed air-ground data exchange in international civil aviation.

SLOVENSKI STANDARD
01-marec-2006
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Electromagnetic compatibility and Radio spectrum Matters (ERM); VHF air-ground Digital
Link (VDL) Mode 2; Technical characteristics and methods of measurement for ground-
based equipment; Part 2: Upper layers
Ta slovenski standard je istoveten z: EN 301 841-2 Version 1.1.1
ICS:
33.060.99 Druga oprema za radijske Other equipment for
komunikacije radiocommunications
33.100.01 Elektromagnetna združljivost Electromagnetic compatibility
na splošno in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

European Standard (Telecommunications series)

Electromagnetic compatibility
and Radio spectrum Matters (ERM);
VHF air-ground Digital Link (VDL) Mode 2;
Technical characteristics and
methods of measurement
for ground-based equipment;
Part 2: Upper layers
2 ETSI EN 301 841-2 V1.1.1 (2004-03)

Reference
DEN/ERM-TG25-015-2
Keywords
aeronautical, radio, testing
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ETSI
3 ETSI EN 301 841-2 V1.1.1 (2004-03)
Contents
Intellectual Property Rights.10
Foreword.10
Introduction .10
1 Scope.11
2 References.11
3 Definitions and abbreviations.12
3.1 Definitions.12
3.1.1 Basic reference model definitions.12
3.1.2 Service conventions definitions .12
3.1.3 General definitions.13
3.2 Abbreviations.13
4 General architecture of VDL Mode 2.14
5 Link layer protocols and services functional specifications.15
5.1 MAC sublayer specifications .16
5.1.1 MAC services.16
5.1.1.1 Multiple access.16
5.1.1.2 Channel congestion.16
5.1.2 MAC service system parameters .17
5.1.2.1 Timer TM1 (inter-access delay timer).17
5.1.2.2 Timer TM2 (channel busy timer).17
5.1.2.3 Parameter p (persistence) .17
5.1.2.4 Counter M1 (maximum number of access attempts) .17
5.1.3 Description of procedures.17
5.1.3.1 Channel sensing.17
5.1.3.2 P-persistent CSMA access times.17
5.1.3.3 Inter-access interval.18
5.1.3.4 Channel access procedure .18
5.1.3.4.1 Purpose.18
5.1.3.4.2 Use.18
5.1.3.4.3 Procedure.18
5.1.3.5 AVLC frame reception.18
5.1.3.5.1 Purpose.18
5.1.3.5.2 Use.18
5.1.3.5.3 Procedure.18
5.2 Data link layer service protocol specifications.19
5.2.1 Interface with MAC sub layer.19
5.2.1.1 Sequence of primitives.19
5.2.2 Data Link State Machines.20
5.2.2.1 LME state machine.21
5.2.2.2 DLE top state machine .22
5.2.2.3 DLE data transfer state diagram.23
5.2.2.4 DLE selective reject state machines.24
5.2.2.4.1 SRM mode Sending SREJ.24
5.2.2.4.2 SRM mode Receiving SREJ.24
5.2.2.4.3 FRM mode.25
5.2.2.5 DLE termination state machine.26
5.2.3 Services.26
5.2.3.1 Received frame sequencing procedure.26
5.2.3.1.1 Purpose.26
5.2.3.1.2 Use.26
5.2.3.1.3 Procedure.26
5.2.3.2 Error detection procedure.26
5.2.3.2.1 Purpose.26
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4 ETSI EN 301 841-2 V1.1.1 (2004-03)
5.2.3.2.2 Use.26
5.2.3.2.3 Procedure.27
5.2.3.3 Station identification.27
5.2.3.4 Broadcast addressing.27
5.2.3.5 Data transfer.27
5.2.4 Frame format.27
5.2.4.1 Address structure.27
5.2.4.2 Address fields0.0.3.3.27
5.2.4.2.1 Air-ground status bit.28
5.2.4.2.2 Command/response status bit .28
5.2.4.2.3 Data link service addresses.28
5.2.4.2.4 Address type.28
5.2.4.2.5 Aircraft specific addresses.28
5.2.4.2.6 ICAO-administered ground station specific addresses .28
5.2.4.2.7 ICAO-delegated ground station specific addresses .28
5.2.4.3 Broadcast address.28
5.2.4.3.1 Encoding.29
5.2.4.4 Link control field .29
5.2.4.5 Information field.29
5.2.5 Transmit queues management.29
5.2.6 Data link service system parameters.30
5.2.6.1 Parameter T1 (delay before non acknowledged retransmission).30
5.2.6.2 Parameter T2 (delay before acknowledgment).31
5.2.6.3 Parameter T3 (link initialization time) .31
5.2.6.4 Parameter T4 (maximum delay between transmissions).31
5.2.6.4.1 Recommendation.31
5.2.6.5 Parameter N1 (maximum number of bits of any frame) .31
5.2.6.6 Counter N2 (maximum number of transmissions) .31
5.2.6.7 Parameter k (window size).32
5.2.7 DLE retransmission timers .32
5.2.8 Description of procedures.32
5.2.8.1 Procedure retransmission schedule .32
5.2.8.1.1 Purpose.32
5.2.8.1.2 Use.32
5.2.8.1.3 Procedure.32
5.2.8.2 Procedure frame retransmission .32
5.2.8.2.1 Purpose.32
5.2.8.2.2 Use.32
5.2.8.2.3 Procedure.33
5.2.8.3 Procedure XID frame retransmission.33
5.2.8.3.1 Purpose.33
5.2.8.3.2 Use.33
5.2.8.3.3 Procedure.33
5.2.8.4 Procedure link monitoring.33
5.2.8.4.1 Purpose.33
5.2.8.4.2 Use.33
5.2.8.4.3 Procedure.33
5.2.8.5 Procedure link recovery .33
5.2.8.5.1 Purpose.33
5.2.8.5.2 Use.33
5.2.8.5.3 Procedure.33
5.2.9 Modes of operation .34
5.2.9.1 Operational mode.34
5.2.9.2 Non-operational mode.34
5.2.9.2.1 DISC frame.34
5.2.9.2.2 DM frame.34
5.2.9.3 Frame reject mode.34
5.2.9.4 Sent selective reject mode.34
5.2.10 Use of the P/F bit .34
5.2.10.1 General.34
5.2.10.2 INFO frames.35
5.2.10.3 Recommendation.35
ETSI
5 ETSI EN 301 841-2 V1.1.1 (2004-03)
5.2.10.4 Unnumbered frames.35
5.2.11 Unnumbered command frame collisions .35
5.2.11.1 DLE procedures.35
5.2.11.2 LME procedures.35
5.2.12 XID frame.35
5.2.13 Broadcast.35
5.2.14 Information transfer.35
5.2.14.1 Void.35
5.2.14.1.1 Eliminate redundant frames.35
5.2.14.1.2 Recommendation.36
5.2.14.1.3 Recommendation.36
5.2.14.1.4 Recommendation.36
5.2.14.1.5 Procedures for transmission.36
5.2.14.1.6 Recommendation.36
5.2.14.1.7 Recommendation.36
5.2.14.1.8 Recommendation.36
5.2.14.2 SREJ frame.36
5.2.14.3 FRMR frame.37
5.2.14.4 UA frame.37
5.2.14.5 UI frame.37
5.2.14.6 TEST frame.37
5.3 VDL management entity.37
5.3.1 Services.37
5.3.1.1 Link provision.37
5.3.1.2 Link change notifications.37
5.3.2 Exchange identity (XID) parameter.38
5.3.2.1 Encoding.38
5.3.2.2 Public parameters.38
5.3.2.2.1 HDLC public parameter set identifier .38
5.3.2.2.2 Timer T1 parameter.39
5.3.2.3 VDL private parameters.39
5.3.2.4 General purpose information private parameters .39
5.3.2.4.1 VDL private parameter set identifier.39
5.3.2.4.2 Connection management parameter.39
5.3.2.4.3 Signal Quality Parameter (SQP).40
5.3.2.4.4 XID sequencing parameter .41
5.3.2.4.5 AVLC specific options parameter .41
5.3.2.4.6 Expedited subnetwork connection parameter .42
5.3.2.4.7 LCR cause parameter .42
5.3.2.5 Aircraft-initiated information private parameters .43
5.3.2.5.1 Modulation support parameter.43
5.3.2.5.2 Acceptable alternate ground station parameter.44
5.3.2.5.3 Destination airport parameter .44
5.3.2.5.4 Aircraft location parameter.44
5.3.2.6 Ground-based initiated modification private parameters .45
5.3.2.6.1 Autotune frequency parameter.45
5.3.2.6.2 Replacement ground station list .45
5.3.2.6.3 Timer T4 parameter.45
5.3.2.6.4 MAC persistence parameter .45
5.3.2.6.5 Counter M1 parameter.46
5.3.2.6.6 Timer TM2 parameter .46
5.3.2.6.7 Timer TG5 parameter .46
5.3.2.6.8 T3min parameter.46
5.3.2.6.9 Ground station address filter parameter.47
5.3.2.6.10 Broadcast connection parameter.47
5.3.2.7 Ground-based initiated information private parameters.48
5.3.2.7.1 Frequency support list .48
5.3.2.7.2 Airport coverage indication parameter .48
5.3.2.7.3 Nearest airport parameter .48
5.3.2.7.4 ATN router NETs parameter .49
5.3.2.7.5 Ground-based system mask parameter .49
5.3.2.7.6 Timer TG3 parameter .49
ETSI
6 ETSI EN 301 841-2 V1.1.1 (2004-03)
5.3.2.7.7 Timer TG4 parameter .50
5.3.2.7.8 Ground station location parameter.50
5.3.3 VME service system parameters.50
5.3.4 VME procedures.50
5.3.4.1 Minimum frequency dwell time procedure.50
5.3.4.1.1 Purpose.50
5.3.4.1.2 Use.51
5.3.4.1.3 Procedure.51
5.3.4.1.4 Recommendation.51
5.3.4.2 Maximum idle activity time procedure .51
5.3.4.2.1 Purpose.51
5.3.4.2.2 Use.51
5.3.4.2.3 Procedure.51
5.3.4.3 Maximum time between transmissions procedure .51
5.3.4.3.1 Purpose.51
5.3.4.3.2 Use.51
5.3.4.3.3 Procedure.51
5.3.4.4 Maximum time between GSIFs.52
5.3.4.4.1 Purpose.52
5.3.4.4.2 Use.52
5.3.4.4.3 Procedure.52
5.3.4.5 Maximum link overlap time procedure.52
5.3.4.5.1 Purpose.52
5.3.4.5.2 Use.52
5.3.4.5.3 Procedure.52
5.3.5 Description of LME procedures.52
5.3.5.1 Frequency management procedures.56
5.3.5.1.1 Frequency search.56
5.3.5.1.2 Frequency recovery.56
5.3.5.2 Link connectivity procedures.57
5.3.5.3 Ground station identification.57
5.3.5.4 Link establishment.57
5.3.5.4.1 Aircraft initiation.57
5.3.5.4.2 General ground response .57
5.3.5.4.3 Exceptional cases.58
5.3.5.5 Link parameter modification.58
5.3.5.5.1 Ground-based initiation.58
5.3.5.5.2 General aircraft response.58
5.3.5.5.3 Recommendation.58
5.3.5.6 Aircraft-initiated handoff.58
5.3.5.6.1 Aircraft handoff.58
5.3.5.6.2 Site selection preference.58
5.3.5.6.3 Recommendation.59
5.3.5.6.4 Interaction of LMEs.59
5.3.5.6.5 General ground response .59
5.3.5.6.6 Disconnecting old link.59
5.3.5.6.7 Exceptional cases.59
5.3.5.7 Aircraft-requested ground-initiated handoff .59
5.3.5.7.1 Aircraft action.59
5.3.5.7.2 General ground response .60
5.3.5.7.3 Exceptional cases.60
5.3.5.8 Ground-based initiated handoff0.60
5.3.5.8.1 Ground action.60
5.3.5.8.2 General aircraft response.60
5.3.5.8.3 Disconnecting old link.60
5.3.5.8.4 Exceptional cases.60
5.3.5.8.5 Recommendation.60
5.3.5.9 Ground-based requested aircraft-initiated handoff0.4.4.9.60
5.3.5.9.1 Ground action.61
5.3.5.9.2 General aircraft response.61
5.3.5.9.3 Exceptional cases.61
5.3.5.9.4 Recommendation.61
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7 ETSI EN 301 841-2 V1.1.1 (2004-03)
5.3.5.10 Ground-based requested broadcast handoff .61
5.3.5.10.1 Ground action.61
5.3.5.10.2 Aircraft response.61
5.3.5.10.3 Exceptional cases.62
5.3.5.11 Ground-based commanded autotune.62
5.3.5.11.1 Ground action.62
5.3.5.11.2 General aircraft response.62
5.3.5.11.3 Exceptional cases.62
5.3.5.12 Expedited subnetwork connection management .62
5.3.5.12.1 Initiating station of subnetwork connection management .63
5.3.5.12.2 General responder action.63
5.3.5.12.3 Exceptional cases.63
6 Subnetwork layer protocols and services functional specifications .63
6.1 Architecture.63
6.1.1 Access points.63
6.2 Services.63
6.2.1 Subnetwork connection management.64
6.2.2 Packet fragmentation and reassembly.64
6.2.3 Error recovery.64
6.2.3.1 Recommendation.64
6.2.4 Connection flow control.64
6.2.4.1 Recommendation.64
6.3 Packet format.64
6.3.1 General format identifier .64
6.3.2 Calling and called DTE addresses .64
6.3.2.1 Encoding.65
6.3.2.1.1 Address field.
...