M/239 -

The present document covers the link and sub-network access layers of Very High Frequency (VHF) Digital Link. The
present document applies to VDL Mode 2 ground-based stations operating in the VHF band (117,975 MHz to
137,000 MHz) with 25 kHz channel spacing and using Differential Eight Phase Shift Keying (D8PSK).
The present document provides functional specifications for ground-based radio transmitters, receivers, and transceivers
intended to be used for ground-air data communications. The present document is derived from the following
documents:
• VDL Mode 2 SARPs. ICAO, annex 10 Volume III part I [1] second edition, July 2007;
• ICAO Doc 9776: "Manual on VHF Digital Link (VDL) Mode 2" [10].

REN/ERM-TGAERO-56

The revision of EN 301 841-1 to make it compliant to the ICAO VDL Mode 2 Manual (Doc 9776 First Edition 2001) and the RTCA specifications which are referenced in the EN (RTCA DO-224B and RTCA DO 281A) - to remove ambiguous text specifying all requirements and test procedures in a non-ambiguous way.
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 [2].
- ED 92a [3]: "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.

REN/AERO-00004

The present document applies to the following radio equipment types:
Very High Frequency (VHF) Digital Link (VDL) Mode 4 ground-based radio transmitters and receivers for air-ground communications operating in the VHF band, using Gaussian-filtered Frequency Shift Keying (GFSK) Modulation with 25 kHz channel spacing and capable of tuning to any of the 25 kHz channels from 118,000 MHz to 136,975 MHz as defined in ICAO VHF Digital Link (VDL) Standards and Recommended Practices (SARPs) [14]. The present document provides part 2 of the technical specifications. The present document is designed to ensure that equipment certified to it will be compatible with the relevant ICAO VHF Digital Link (VDL) Standards and Recommended Practices (SARPs) [14] and VDL Mode 4 Technical Manual (TM) [1] and with the SES 552/2004 interoperability Regulation [16]. Manufacturers should note that in future the tuning range for the ground transceivers may also cover any 25 kHz channel from 108,000 MHz to 117,975 MHz. The scope of the present document is limited to ground stations. The equivalent specification for airborne stations is EN 302 842 [13]. The VDL Mode 4 system provides data communication exchanges between aircraft and ground based systems supporting surveillance and communication applications. The supported modes of communication include:
broadcast and point-to-point communication;
broadcast services including Automatic Dependent Surveillance-Broadcast (ADS-B), Traffic Information Service-Broadcast (TIS-B) and Flight Information Service-Broadcast (FIS-B) capabilities;
air-to-air, air-to-ground, ground-to-air and ground mobile services;
operation without ground infrastructure.
VDL Mode 4 is designed to be an Air/Ground subsystem of the Aeronautical Telecommunication Network (ATN) [8] using the AM(R)S band and it is organized according to the Open Systems Interconnection (OSI) model (defined by ISO). It provides reliable sub network services to the ATN system. Other networks can also be supported but these have not been focussed on in the present document. The present document specifies functional specifications of VHF communication ground station equipment intended to be used for air-ground and air-air data communications. The present document is derived from the standards and specifications in:
VDL Mode 4 standards produced under the auspices of the International Civil Aviation Organization
(ICAO) [1].
Other relevant standards as defined in clause 2.
It is envisaged that manufacturers may provide equipment supporting:
broadcast services only;
point-to-point services only;
both broadcast and point-to-point services.
EN 301 842-1 [4] deals with tests of the physical layer. The present document defines the core link layer requirements for the VDL Mode 4 ground station necessary to support all types of equipment. This includes a simple position broadcast functionality. The present document deals with tests of the link layer sufficient to support core link layer functionality, and it also includes requirements and tests sufficient to recognize and respond to transmissions associated with point-to-point communication. The present document does not address requirements for the full ADS-B message set, or for other broadcast applications that can be supported by the VDL Mode 4 equipment. These are covered by EN 301 842-3 [9]. Detailed requirements for point-to-point communication are beyond the scope of the present document, but can be found in EN 301 842-4 [10]. EN 301 842-4 [10] also includes the interface to the Aeronautical Telecommunication Network (ATN) as defined in ATN SARPs [8].
As the measured values of equipment performance may be a function of the method of measurement, standard test conditions and methods of test are recommended in the present document.

The present document applies to the following radio equipment types:
Very High Frequency (VHF) Digital Link (VDL) Mode 4 ground-based radio transmitters and receivers for air-ground communications operating in the VHF band, using Gaussian-filtered Frequency Shift Keying (GFSK) Modulation with 25 kHz channel spacing and capable of tuning to any of the 25 kHz channels from 118,000 MHz to 136,975 MHz as defined in ICAO VHF Digital Link (VDL) Standards and Recommended Practices (SARPs) [2]. The present document provides part 1 of the technical specification. The present document is designed to ensure that equipment certified to it will be compatible with the relevant ICAO VHF Digital Link (VDL) Standards and Recommended Practices (SARPs) [2] and VDL Mode 4 Technical Manual (TM) [1] and with the SES 552/2004 interoperability Regulation [10]. Manufacturers should note that in future the tuning range for the ground transceivers may also cover any 25 kHz channel from 108,000 MHz to 117,975 MHz. The scope of the present document is limited to ground stations. The equivalent specification for airborne stations is EN 302 842 [8]. The VDL Mode 4 system provides digital communication exchanges between aircraft and ground-based systems and other aircraft supporting surveillance and communication applications. The supported modes of communication include:
broadcast and point-to-point communication;
broadcast services including Automatic Dependent Surveillance-broadcast (ADS-B), Traffic Information Service - Broadcast (TIS-B) and Flight Information Service - Broadcast (FIS-B) capabilities;
air-air, air-to-ground, and ground-to-air services;
operation without ground infrastructure.
The present document is derived from the specifications:
VDL Mode 4 standards produced under the auspices of the International Civil Aviation Organization
(ICAO) [1] and [2];
Other relevant standards as defined in clause 2.
It is envisaged that manufacturers may provide equipment supporting:
broadcast services only;
point-to-point services only;
both broadcast and point-to-point services.
The present document deals with tests of the physical layer necessary to support all types of equipment.
The present document includes:
clause 2 provides references to relevant documents;
clause 3 provides general definitions, abbreviations and symbols used;
clause 4 refers to a general description and architecture of VDL Mode 4 contained in
EN 301 842-2 [7];
clause 5 provides functional specifications applicable to the physical layer including transmitter/receiver requirements and the modulation scheme;
clause 6 provides general equipment requirements;
clause 7 provides general design requirements;
clause 8 covers general test conditions, environmental tests and calibration;
clause 9 provides detailed test procedures for the physical layer;
annex A provides a detailed cross-reference to the relevant requirements contained in reference [1];
annex B provides a Bibliography;
a document history.
The full physical layer tests are provided which correspond closely to the standard set of tests used for other VDL systems.

The present document applies to the following radio equipment types:
Very High Frequency (VHF) Digital Link (VDL) Mode 4 ground-based radio transmitters and receivers for air-ground communications operating in the VHF band, using Gaussian-filtered Frequency Shift Keying (GFSK) Modulation with 25 kHz channel spacing and capable of tuning to any of the 25 kHz channels from 118,000 MHz to 136,975 MHz as defined in ICAO VHF Digital Link (VDL) Standards and Recommended Practices (SARPs) [10]. The present document provides part 3 of the technical specifications. The present document is designed to ensure that equipment certified to it will be compatible with the relevant ICAO VHF Digital Link (VDL) Standards and Recommended Practices (SARPs) [10] and VDL Mode 4 Technical Manual (TM) [1] and with the SES 552/2004 interoperability Regulation [12]. Manufacturers should note that in future the tuning range for the ground transceivers may also cover any 25 kHz channel from 108,000 MHz to 117,975 MHz. The scope of the present document is limited to ground stations. The equivalent specification for airborne stations is EN 302 842 [9]. A description of the scope of the VDL Mode 4 system is provided in part 2 of these technical specifications (see EN 301 842-2 [5] clause 1). EN 301 842-1 [4] deals with tests of the physical layer. EN 301 842-2 [5] deals with tests of the link layer sufficient to support broadcast functionality including requirements and tests sufficient to recognize and respond to transmissions associated with point-to-point communication. The present document provides technical specifications for a VDL Mode 4 ground-based transceiver supporting a full Automatic Dependent Surveillance-Broadcast (ADS-B) capability and, optionally, the additional functionality of either, or a combination of, the following services:

REN/ERM-TG25-029-3

REN/ERM-TG25-029-1

REN/ERM-TG25-029-2

The present document provides part 1 of the technical specifications for Very High Frequency (VHF) Digital Link (VDL) Mode 4 ground-based radio transmitters and receivers for air-ground communications operating in the VHF band, using Gaussian-filtered Frequency Shift Keying (GFSK) Modulation with 25 kHz channel spacing and capable of tuning to any of the 25 kHz channels from 118,000 MHz to 136,975 MHz as defined in ICAO VHF Digital Link (VDL) Standards and Recommended Practices (SARPs) [2]. The present document is designed to ensure that equipment certified to it will be compatible with the relevant ICAO VHF Digital Link (VDL) Standards and Recommended Practices (SARPs) [2] and VDL Mode 4 Technical Manual (TM) [1].
Manufacturers should note that in future the tuning range for the ground transceivers may also cover any 25 kHz channel from 108,000 MHz to 117,975 MHz. The scope of the present document is limited to ground stations. The equivalent specification for airborne stations is EN 302 842 [8].
The VDL Mode 4 system provides digital communication exchanges between aircraft and ground-based systems and other aircraft supporting surveillance and communication applications. The supported modes of communication include:
• broadcast and point-to-point communication;
• broadcast services including Automatic Dependent Surveillance - Broadcast (ADS-B), Traffic Information Service - Broadcast (TIS-B) and Flight Information Service - Broadcast (FIS-B) capabilities;
• air-air, air-to-ground, and ground-to-air services;
• operation without ground infrastructure.
The present document is derived from the specifications:
• VDL Mode 4 standards produced under the auspices of the International Civil Aviation Organization (ICAO) [1] and [2].
• Other relevant standards as defined in clause 2.
It is envisaged that manufacturers may provide equipment supporting:
• broadcast services only;
• point-to-point services only;
• both broadcast and point-to-point services.
The present document deals with tests of the physical layer necessary to support all types of equipment. The present document includes:
• Clause 2 provides references to relevant documents.
• Clause 3 provides general definitions, abbreviations and symbols used.
• Clause 4 provides refers to a general description and architecture of VDL Mode 4 contained in EN 301 842-2 [7].
• Clause 5 provides functional specifications applicable to the physical layer including transmitter/receiver requirements and the modulation scheme.
• Clause 6 provides general equipment requirements.
• Clause 7 provides general design requirements.
• Clause 8 covers general test conditions, environmental tests and calibration.
• Clause 9 provides detailed test procedures for the physical layer.
The full physical layer tests are provided which correspond closely to the standard set of tests used for other VDL systems.
Mandating and Recommendation Phrases
a) "Shall"
The use of the word "Shall" indicates a mandated criterion; i.e. compliance with the particular procedure or specification is mandatory and no alternative may be applied.
b) "Should"
The use of the word "Should" (and phrases such as "It is recommended that...", etc.) indicate that though the procedure or criterion is regarded as the preferred option, alternative procedures, specifications or criteria may be applied, provided that the manufacturer, installer or tester can provide information or data to adequately support and justify the alternative.

The present document states part 2 of the minimum performance requirements for VHF Datalink Mode 4 (VDL Mode 4) ground station equipment intended to be used for air-ground data communications, operating in the VHF band (117,975 MHz to 136,975 MHz and optionally 112,000 MHz to 117,975 MHz) allocated to the aeronautical mobile service. The equipment is also intended to be interoperable with mobile equipment supporting air-air data communications. It is designed to ensure that equipment certified to it will be compatible with the relevant ICAO VHF Digital Link (VDL) Standards and Recommended Practices (SARPs) and VDL Mode 4 Technical Manual (TM) [1]. Manufacturers should note that all or part of the frequency band 108,000 MHz to 117,975 MHz might become available for aeronautical communications. The present document applies to Gaussian-filtered Frequency Shift Keying (GFSK) systems, with channel separations of 25 kHz intended for air-ground communications. The scope of the present document is limited to ground base stations.
The VDL system provides data communication exchanges between aircraft and ground based systems supporting surveillance and communication applications. The supported modes of communication include:
• broadcast and point-to-point communication;
• broadcast services including Automatic Dependent Surveillance - Broadcast (ADS-B), Traffic Information Service – Broadcast (TIS-B) and Flight Information Service - Broadcast (FIS-B) capabilities;
• air-air and ground-air services;
• operation without ground infrastructure.
VDL Mode 4 is designed to be an Air/Ground subsystem of the Aeronautical Telecommunication Network (ATN) [8] using the AM(R)S band and it is organized according to the Open Systems Interconnection (OSI) model (defined by ISO). It provides reliable sub network services to the ATN system. Other networks can also be supported but these have not been focussed on in the present document.
The present document specifies functional specifications of VHF communication ground station equipment intended to be used for air-ground and air-air data communications.

The present document provides part 2 of the technical specifications for Very High Frequency (VHF) Digital Link (VDL) Mode 4 ground-based radio transmitters and receivers for air-ground communications operating in the VHF band, using Gaussian-filtered Frequency Shift Keying (GFSK) Modulation with 25 kHz channel spacing and capable of tuning to any of the 25 kHz channels from 118,000 MHz to 136,975 MHz as defined in ICAO VHF Digital Link (VDL) Standards and Recommended Practices (SARPs) [14]. The present document is designed to ensure that equipment certified to it will be compatible with the relevant ICAO VHF Digital Link (VDL) Standards and Recommended Practices (SARPs) [14] and VDL Mode 4 Technical Manual (TM) [1].
Manufacturers should note that in future the tuning range for the ground transceivers may also cover any 25 kHz channel from 108,000 MHz to 117,975 MHz. The scope of the present document is limited to ground stations. The equivalent specification for airborne stations is EN 302 842 [13].
The VDL Mode 4 system provides data communication exchanges between aircraft and ground based systems supporting surveillance and communication applications. The supported modes of communication include:
• broadcast and point-to-point communication;
• broadcast services including Automatic Dependent Surveillance - Broadcast (ADS-B), Traffic Information Service - Broadcast (TIS-B) and Flight Information Service - Broadcast (FIS-B) capabilities;
• air-to-air, air-to-ground, ground-to-air and ground mobile services;
• operation without ground infrastructure.
VDL Mode 4 is designed to be an Air/Ground subsystem of the Aeronautical Telecommunication Network (ATN) [8] using the AM(R)S band and it is organized according to the Open Systems Interconnection (OSI) model (defined by ISO). It provides reliable sub network services to the ATN system. Other networks can also be supported but these have not been focussed on in the present document.
The present document specifies functional specifications of VHF communication ground station equipment intended to be used for air-ground and air-air data communications. The present document is derived from the standards and specifications in:
• VDL Mode 4 standards produced under the auspices of the International Civil Aviation Organization (ICAO) [1].
• Other relevant standards as defined in clause 2.
It is envisaged that manufacturers may provide equipment supporting:
• broadcast services only;
• point-to-point services only;
• both broadcast and point-to-point services.
EN 301 842-1 [4] deals with tests of the physical layer. The present document defines the core link layer requirements for the VDL Mode 4 ground station necessary to support all types of equipment. This includes a simple position broadcast functionality.

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.

REN/ERM-TG25-026-1

REN/ERM-TG25-026-2

REN/ERM-TG25-023

Profile Standard specifying the combination of base Standards, together with selection of options and parameter values for the use of QSIG/PSS1 in Air Traffic Management communication networks.

DEN/ERM-TG25-015-2

Integration of the MAC/DLS layers and SQP requirements into the EN 301 841-1 v 1.1.1 document based on the existing input of Telerad.

To update the standard in the light of changes to the ICAO SARPS (in particular the DLS protocol).

REN/ERM-TG25-022-1

REN/ERM-TG25-021

This EN will cover VHF aeronautical radio equipment operating at 25 kHz channel spacing in the aeronautical band 118-136.975MHz. It covers ground-based, fixed data communication,  VHF Data Link (VDL) mode 2.  Reference documents: EUROCAE WG47 vdl MODE 2 MOPS Draft version .09

This EN will cover VHF aeronautical radio equipment operating at 25 kHz channel spacing in the aeronautical band 118-136.975MHz. It covers ground-based, fixed data communication,  VHF Data Link (VDL) mode 4.  Reference documents: EUROCAE WG51 vdl MODE 4 MOPS ICAO SARPS on VDL mode 4

This EN will cover VHF aeronautical radio equipment operating at 25 kHz channel spacing in the aeronautical band 118-136.975MHz. It covers ground-based, fixed data communication,  VHF Data Link (VDL) mode 4.  Reference documents: EUROCAE WG51 vdl MODE 4 MOPS ICAO SARPS on VDL mode 4

DEN/ERM-RP05-016-2

DEN/ERM-RP05-015-1

DEN/ERM-RP05-016-1

DEN/ECMA-00189