ETSI EN 301 842-1 V1.3.3 (2011-07)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.KQLþQHVHF air-ground Digital Link (VDL) Mode 4 radio equipment - Technical characteristics and methods of measurement for ground-based equipment - Part 1: EN for ground equipment49.090On-board equipment and instruments33.060.99Druga oprema za radijske komunikacijeOther equipment for radiocommunicationsICS:Ta slovenski standard je istoveten z:EN 301 842-1 Version 1.3.3SIST EN 301 842-1 V1.3.3:2011en01-september-2011SIST EN 301 842-1 V1.3.3:2011SLOVENSKI
STANDARD
ETSI ETSI EN 301 842-1 V1.3.3 (2011-07) 2
Reference REN/AERO-00010-1 Keywords aeronautical, digital, radio, testing, VHF ETSI 650 Route des Lucioles F-06921 Sophia Antipolis Cedex - FRANCE
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© European Telecommunications Standards Institute 2011. All rights reserved.
DECTTM, PLUGTESTSTM, UMTSTM and the ETSI logo are Trade Marks of ETSI registered for the benefit of its Members. 3GPPTM and LTE™ are Trade Marks of ETSI registered for the benefit of its Members and of the 3GPP Organizational Partners. GSM® and the GSM logo are Trade Marks registered and owned by the GSM Association. SIST EN 301 842-1 V1.3.3:2011

ETSI ETSI EN 301 842-1 V1.3.3 (2011-07) 3 Contents Intellectual Property Rights . 6 Foreword . 6 Introduction . 7 1 Scope . 8 2 References . 9 2.1 Normative references . 9 2.2 Informative references . 10 3 Definitions and abbreviations . 10 3.1 Definitions . 10 3.1.1 Basic reference model definitions . 10 3.1.2 Service conventions definitions . 10 3.1.3 General definitions . 11 3.2 Abbreviations . 15 4 General description and architecture of VDL Mode 4 . 16 4.1 General . 16 5 VDL Mode 4 physical layer functional specifications . 16 5.1 Overview . 16 5.1.1 Functions . 16 5.1.2 Data reception . 16 5.1.3 Data transmission . 16 5.2 Modulation scheme . 16 6 VDL Mode 4 equipment requirements . 17 6.1 Receiver Requirements . 17 6.1.1 Receiver operating range . 17 6.1.2 BER requirement . 17 6.1.3 Reference signal level . 17 6.1.4 Sensitivity . 17 6.1.5 Adjacent channel rejection . 17 6.1.6 Rejection of signals within the VHF Aeronautical band. 18 6.1.7 Rejection of signals outside the VHF Aeronautical band . 18 6.1.8 Desired signal dynamic range . 18 6.1.9 Symbol rate capture range . 18 6.1.10 Frequency capture range . 19 6.1.11 Co-channel interference . 19 6.1.12 Conducted spurious emission . 19 6.1.13 FM Broadcast Intermodulation . 19 6.1.13.1 Radio frequencies in the band 117,975 MHz to 137 MHz . 19 6.1.14 In-band Intermodulation . 19 6.1.15 Cabinet radiation . 20 6.2 Transmitter requirements . 20 6.2.1 Transmitter operating range . 20 6.2.2 Channel Bit Rate . 20 6.2.3 Protection of the transmitter. 20 6.2.4 Manufacturer's declared output power . 20 6.2.5 RF power rise time . 20 6.2.6 RF power release time . 21 6.2.7 Conducted Spurious emissions . 21 6.2.8 Adjacent channel power . 21 6.2.9 Wide-band noise . 21 6.2.10 Frequency Tolerance. 21 6.2.11 Load VSWR capability . 22 6.2.12 Cabinet radiation . 22 SIST EN 301 842-1 V1.3.3:2011

ETSI ETSI EN 301 842-1 V1.3.3 (2011-07) 4 6.3 Transceiver requirements . 22 6.3.1 Start of transmission . 22 6.3.2 Automatic transmitter shutdown . 22 6.3.3 Receiver to transmitter turnaround time . 22 6.3.4 Transmitter to receiver turnaround time . 22 6.3.5 System timing requirements . 22 7 General design requirements . 22 7.1 Controls and indicators . 22 7.2 Class of emission and modulation characteristics . 22 7.3 Warm up . 23 8 Test conditions, power sources and ambient temperatures . 23 8.1 Test power source . 23 8.2 Test channels . 23 8.3 General conditions of measurement . 23 8.3.1 Receiver test signal arrangement . 23 8.3.2 Performance check . 23 8.4 Normal and extreme test conditions . 24 8.4.1 Normal test conditions . 24 8.4.1.1 Normal temperature and humidity . 24 8.4.1.2 Normal power sources . 24 8.4.1.2.1 Mains voltage and frequency . 24 8.4.1.2.2 Other power sources . 24 8.4.2 Extreme test conditions . 24 8.4.2.1 Extreme temperatures . 24 8.4.2.2 Procedure for tests at extreme temperatures . 24 8.4.2.2.1 General . 24 8.4.2.2.2 High temperature . 25 8.4.2.2.3 Low temperature . 25 8.4.2.3 Extreme values of test power sources . 25 8.4.2.3.1 Mains voltage and frequency . 25 9 Detailed Test Procedures for the physical layer . 25 9.1 Receiver . 25 9.1.1 BER test . 25 9.1.2 Sensitivity . 27 9.1.3 Adjacent Channel Rejection (ACR) . 28 9.1.4 Rejection of signals within the VHF Aeronautical band. 28 9.1.5 Rejection of signals outside the VHF Aeronautical band . 29 9.1.6 Desired Signal dynamic range . 30 9.1.7 Symbol rate capture range . 31 9.1.8 Frequency capture range . 31 9.1.9 Co-channel interference . 32 9.1.10 Conducted spurious emission . 32 9.1.11 In-band Intermodulation . 33 9.2 Transmitter . 34 9.2.1 Channel Bit Rate . 34 9.2.2 Manufacturer's declared output power . 34 9.2.3 RF power rise time . 34 9.2.4 RF power release time . 35 9.2.5 Spurious emissions . 35 9.2.6 Adjacent channel power . 36 9.2.6.1 Method of measurement for the first adjacent channel . 36 9.2.6.2 Method of measurement for the second adjacent channel . 37 9.2.6.3 Method of measurement for the fourth adjacent channel . 38 9.2.6.4 Alternative measurement procedure for Adjacent Channel Power (ACP) . 38 9.2.7 Wide-band noise . 39 9.2.8 Frequency Error . 40 9.2.8.1 Definition . 40 9.2.8.2 Method of measurement . 40 9.2.8.3 Limits . 40 9.2.9 Load VSWR capability . 40 SIST EN 301 842-1 V1.3.3:2011

ETSI ETSI EN 301 842-1 V1.3.3 (2011-07) 5 9.3 Physical layer, system parameters . 41 9.3.1 Receiver to Transmitter turn-around time . 41 9.3.2 Transmitter to Receiver turn-around time . 42 9.3.3 Tuning Time . 42 Annex A (informative): Cross reference matrix . 43 Annex B (informative): Bibliography . 45 History . 47
ETSI ETSI EN 301 842-1 V1.3.3 (2011-07) 6 Intellectual Property Rights IPRs essential or potentially essential to the present document may have been declared to ETSI. The information pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web server (http://ipr.etsi.org). Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may become, essential to the present document. Foreword This European Standard (EN) has been produced by ETSI Technical Committee Aeronautics (AERO). The present document is part 1 of a multi-part deliverable covering the VHF air-ground Digital Link (VDL) Mode 4 radio equipment; Technical characteristics and methods of measurement for ground-based equipment, as identified below: Part 1: "EN for ground equipment"; Part 2: "General description and data link layer"; Part 3: "Additional broadcast aspects"; Part 4: "Point-to-point functions"; Part 5: "Harmonized EN covering the essential requirements of article 3.2 of the R&TTE Directive". The present document is accompanied by an equivalent airborne standard, EN 302 842 [8] parts 1 to 4, covering the VHF air-ground Digital Link (VDL) Mode 4 radio equipment; Technical characteristics and methods of measurement for airborne equipment. NOTE: Following the decision taken at the ICAO Aeronautical Communication Panel (Bangkok, February 2011), it is expected that ICAO Annex 10 will be amended in 2012 changing the frequency range from 108 MHz to 137,975 MHz to 112 MHz to 137,975 MHz. The present deliverable will be updated accordingly once the amendment is publicly available.
National transposition dates Date of latest announcement of this EN (doa): 31 October 2011 Date of latest publication of new National Standard or endorsement of this EN (dop/e):
30 April 2012 Date of withdrawal of any conflicting National Standard (dow): 30 April 2012
ETSI ETSI EN 301 842-1 V1.3.3 (2011-07) 7 Introduction The present document is part of a set of standards developed by ETSI and is designed to fit in a modular structure to cover all radio and telecommunications terminal equipment within the scope of the R&TTE Directive [i.1]. The modular structure is shown in EG 201 399 [i.2]. The present document states the technical specifications for Very High Frequency (VHF) Digital Link (VDL) Mode 4 ground-based radio transmitters, transceivers 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 may be used to produce tests for the assessment of the performance of the equipment. The performance of the equipment submitted for type testing should be representative of the performance of the corresponding production model. The present document has been written on the assumption that: • the type test measurements will be performed only once, in an accredited test laboratory and the measurements accepted by the various authorities in order to grant type approval; • if equipment available on the market is required to be checked it may be tested in accordance with the methods of measurement specified in the present document or a documented alternative approved by the certifying authority; • equipment comply with EN 301 489-22 [6]. SIST EN 301 842-1 V1.3.3:2011

ETSI ETSI EN 301 842-1 V1.3.3 (2011-07) 8 1 Scope 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]. 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; SIST EN 301 842-1 V1.3.3:2011

ETSI ETSI EN 301 842-1 V1.3.3 (2011-07) 9 • 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. 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. 2 References References are either specific (identified by date of publication and/or edition number or version number) or non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the reference document (including any amendments) applies. Referenced documents which are not found to be publicly available in the expected location might be found at http://docbox.etsi.org/Reference. NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee their long term validity. 2.1 Normative references The following referenced documents are necessary for the application of the present document. [1] ICAO Doc 9816 AN/448 (First Edition 2004): "Manual on VHF Digital Link (VDL) Mode 4, Part 2: Detailed Technical Specifications". [2] ICAO Annex 10 to the Convention on International Civil Aviation: "Aeronautical Telecommunications, Volume III: Communication Systems, Part I: Digital Data Communication Systems, Chapter 6". [3] ISO/IEC 7498-1 (1994): "Information technology - Open Systems Interconnection - Basic Reference Model: The Basic Model". [4] ISO/IEC 10731 (1994): "Information technology - Open Systems Interconnection - Basic Reference Model - Conventions for the definition of OSI services". [5] ETSI EN 300 113-1 (V1.6.2): "Electromagnetic compatibility and Radio spectrum Matters (ERM); Land mobile service; Radio equipment intended for the transmission of data (and/or speech) using constant or non-constant envelope modulation and having an antenna connector; Part 1: Technical characteristics and methods of measurement". SIST EN 301 842-1 V1.3.3:2011

ETSI ETSI EN 301 842-1 V1.3.3 (2011-07) 10 [6] ETSI EN 301 489-22 (V1.3.1): "Electromagnetic compatibility and Radio spectrum Matters (ERM); ElectroMagnetic Compatibility (EMC) standard for radio equipment and services; Part 22: Specific conditions for ground based VHF aeronautical mobile and fixed radio equipment". [7] ETSI EN 301 842-2 (V1.6.1): "VHF air-ground Digital Link (VDL) Mode 4 radio equipment; Technical characteristics and methods of measurement for ground-based equipment; Part 2: General description and data link layer". [8] ETSI EN 302 842 (all parts): "VHF air-ground and air-air Digital Link (VDL) Mode 4 radio equipment; Technical characteristics and methods of measurement for aeronautical mobile (airborne) equipment". 2.2 Informative references The following referenced documents are not necessary for the application of the present document but they assist the user with regard to a particular subject area. [i.1] Directive 1999/5/EC of the European Parliament and of the Council of 9 March 1999 on radio equipment and telecommunications terminal equipment and the mutual recognition of their conformity (R&TTE Directive). [i.2] ETSI EG 201 399: "Electromagnetic compatibility and Radio spectrum Matters (ERM); A guide to the production of Harmonized Standards for application under the R&TTE Directive". 3 Definitions and abbreviations 3.1 Definitions 3.1.1 Basic reference model definitions The present document is based on the concepts developed in the open systems interconnect basic reference model and makes use of the following terms defined in ISO/IEC 7498-1 [3]: • layer; • sublayer; • entity; • service; • service access point; • service data unit; • physical layer; • data link layer. 3.1.2 Service conventions definitions The present document makes use of the following terms defined in ISO/IEC 10731 [4]: • service provider; • service user; • service primitive; SIST EN 301 842-1 V1.3.3:2011

ETSI ETSI EN 301 842-1 V1.3.3 (2011-07) 11 • request; • indication; • confirm. 3.1.3 General definitions For the purposes of the present document, the following terms and definitions apply: adjacent channel power: amount of the modulated RF signal power which falls within a given adjacent channel NOTE: Adjacent channel power includes discrete spurious, signal sidebands, and noise density (including phase noise) at the transmitter output. Adjacent Channel Rejection (ACR): receiver's ability to demodulate the desired signal and meet the BER requirement in the presence of an interfering signal in an adjacent channel NOTE: The ratio (in dB) between the adjacent interfering signal level and the desired signal level necessary to achieve the specified minimum BER, is the adjacent channel rejection (ACR) ratio. Aeronautical Mobile Service (AMS): mobile service between aeronautical stations and aircraft stations, or between aircraft stations, in which survival craft stations may participate Aeronautical Telecommunications Network (ATN): internetwork architecture that allows ground, air/ground, and aircraft data subnetworks to interoperate by adopting common interface services and protocols based on the International Organization for Standardization Open Systems Interconnection (OSI) Reference Model aircraft address: unique combination of 24 bits available for assignment to an aircraft for the purpose of air-ground communications, navigation and surveillance NOTE: An aircraft may choose not to use this unique address and can use instead a non-unique address. Automatic Dependent Surveillance-Broadcast (ADS-B): surveillance application transmitting parameters, such as position, track and ground speed, via a broadcast mode data link for use by any air and ground users requiring it NOTE: ADS-B is a surveillance service based on aircraft self-determination of position/velocity/time and automatic, periodic or random, broadcast of this information along with auxiliary data such as aircraft identity (ID), communications control parameters, etc. ADS-B is intended to support multiple high-level applications and associated services such as cockpit display of traffic information, traffic alert and collision avoidance functionality, enhanced traffic management in the air and on the ground, search and rescue support and others. autotune function: function, performed by the Link Management Entity, that allows a ground VDL Mode 4 station to command an aircraft to change the operating characteristics of synchronization burst transmissions Bit Error Rate (BER): expressed as the ratio between the number of erroneous bits received and the total number of bits received burst length: number of slots across which the VDL Mode 4 burst is transmitted Co-Channel Interference (CCI): co-channel interference protection defines the capability of a receiver to demodulate the desired signal and achieve the minimum specified BER performance in the presence of an unwanted signal at the same assigned frequency NOTE: The ratio (in dB) between the wanted signal level and the unwanted signal level is the co-channel interference ratio. The co-channel interference ratio has a major impact on frequency re-use planning criteria. conducted measurements: measurements which are made using a direct RF connection to the equipment under test current slot: slot in which a received transmission begins Data Link Entity (DLE): protocol state machine capable of setting up and managing a single data link connection SIST EN 301 842-1 V1.3.3:2011

ETSI ETSI EN 301 842-1 V1.3.3 (2011-07) 12 Data Link Service (DLS) sublayer: sublayer that resides above the VDL Mode 4 Specific Services (VSS) and the MAC sublayers NOTE: The Data Link Service (DLS) manages the transmit queue, creates and destroys Data Link Entities (DLEs) for connection-oriented communications, provides facilities for the Link Management Entity (LME) to manage the DLS, and provides facilities for connection-less communications. data rate: Mode 4 nominal data rate is 19 200 bits/s delayed burst: VDL Mode 4 burst that begins sufficiently after the beginning of a slot so that the transmitting VDL Mode 4 station is confident that no other VDL Mode 4 station that it could receive from and is within the guard range is transmitting in the slot NOTE: The delayed VDL Mode 4 burst terminates by the end of the slot in which it began (its length is shortened to ensure completion by the nominal time). DLS system: VDL system that implements the DLS and subnetwork protocols to carry Aeronautical Telecommunications Network (ATN) or other packets frame: link layer frame is composed of a sequence of address, control, information and FCS fields, bracketed by opening and closing flag sequences NOTE: A valid frame is at least 11 octets in length and contains an address field (8 octets), a link control field (1 octet) and a frame check sequence (2 octets). A frame may or may not include a variable-length information field. Global Signalling Channel (GSC): channel available on a world wide basis which provides for communication control ground base station: aeronautical station equipment, in the aeronautical mobile service, for use with an external antenna and intended for use at a fixed location ground station coordination: coordination of transmissions from two or more ground stations uses the UTC-minute time frame hand held: radio equipment with integral batteries, designed to be hand portable and operated hand held NOTE: Provisions may be made for external connections and temporary installation into vehicles. integral antenna equipment: radio communications equipment with an antenna integrated into the equipment without the use of an external connector and considered to be part of the equipment NOTE: An integral antenna may be internal or external to the equipment. In equipment of this type, a 50 Ω RF connection point should be provided for test purposes. link: connects a mobile DLE and a ground DLE and is uniquely specified by the combination of mobile DLS address and the ground DLS address NOTE: A different subnetwork entity resides above every link endpoint. link establishment: process by which two stations discover each other, determine to communicate with each other, decide upon the communication parameters, create a link and initialize its state before beginning communications link handoff: process by which peer LMEs, already in communication with each other, create a link between an aircraft and a new ground station before disconnecting the old link between the aircraft and the current ground station link layer: layer that lies immediately above the physical layer in the Open Systems Interconnection protocol model NOTE: The link layer provides for the reliable transfer of information across the physical media. It is subdivided into the data link sublayer and the media access control sublayer. SIST EN 301 842-1 V1.3.3:2011

ETSI ETSI EN 301 842-1 V1.3.3 (2011-07) 13 Link Management Entity (LME): protocol state machine capable of acquiring, establishing, and maintaining a connection to a single peer system NOTE: An LME establishes data link and subnetwork connections, "hands-off" those connections, and manages the media access control sublayer and physical layer. An aircraft LME tracks how well it can communicate with the ground stations of a single ground system. An aircraft VDL management entity (VME) instantiates an LME for each ground station that it monitors. Similarly, the ground VME instantiates an LME for each aircraft that it monitors. An LME is deleted when communication with the peer system is no longer viable. Media Access Control (MAC): sublayer that acquires the data path and controls the movement of bits over the data path mobile: radio equipment designed for installation into vehicles non-integral antenna equipment: radio communications equipment with a connector intended for connection to an antenna physical layer: lowest level layer in the Open Systems Interconnection protocol model NOTE: The physical layer is concerned with only the transmission of binary information over the physical medium (e.g. VHF radio). primary time source: normal operation timing mode in which a VDL Mode 4 station maintains time synchronization to Universal Coordinated Time (UTC) second to within a two-sigma value of 400 ns private parameters: parameters that are contained in exchange identity (XID) frames and that are unique to the VHF digital link environment radiated measurements: measurements which involve the measurement of a radiated field reference bit sequence: sequence of bits used in the transmitter performance specifications reference signal level: signal level used in the receiver performance specifications except otherwise stated secondary time source: timing source used in a failure mode, which applies when the primary time source fails, in which a VDL Mode 4 station maintains time synchronization to UTC second to within a two-sigma value of 15 µs Self-organizing Time Division Multiple Access (STDMA): multiple access scheme based on time-shared use of a radio frequency (RF) channel employing:
1) discrete contiguous time slots as the fundamental shared resource; and
2) a set of operating protocols that allows users to mediate access to these time slots without reliance on a master control station. slot: In VDL Mode 4, time is divided into a series of time slots of equal period. Each VDL Mode 4 burst transmission starts at the beginning of a slot. station: VDL Mode 4 Specific Services (VSS)-capable entity NOTE: A station may be either a mobile station or a ground station. A station is a physical entity that transmits and receives bursts over the RF interface (either A/G or Air-to-Air (A/A)) and comprises, at a minimum: a physical layer, media access control sublayer, and a unique VSS address. A station which is also a DLS station has the same address. subnetwork layer: layer that establishes, manages, and terminates connections across a subnetwork superframe: group of 4 500 slots that span a period of one UTC minute NOTE: The start of the current superframe is aligned with the start of the slot that is currently being used for transmission. The next superframe starts one minute after the current slot. SIST EN 301 842-1 V1.3.3:2011

ETSI ETSI EN 301 842-1 V1.3.3 (2011-07) 14 synchronization burst (or "sync" burst): VDL Mode 4 burst which announces, as a minimum, existence and position NOTE: Ground stations announce existence, position, and the current time. Mobile stations lacking timing information can then derive the slot structure from ground synchronization bursts. Mobile stations lacking position information can derive position from both mobile and ground synchronization bursts. This periodic information is used in various ways including ADS-B, secondary navigation, and simplifying the LME algorithms. Time Division Multiple Access (TDMA): multiple access scheme based on time-shared use of an RF channel employing:
1) discrete contiguous time slots as the fundamental shared resource; and
2) a set of operating protocols that allows users to interact with a master control station to mediate access to the channel. unicasted transmission: transmission addressed to a single station VDL Management Entity (VME): VDL-specific entity that provides the quality of service requested by the ATN-defined subnetwork system management entity NOTE: A VME uses the LMEs (that it creates and destroys) to acquire the quality of service available from peer systems. VDL Mode 2: VHF data link using a differentially encoded 8 phase shift keying modulation scheme and carrier sense multiple access VDL Mode 4: VHF data link using a Gaussian-filtered Frequency Shift Keying (GFSK) modulation scheme and self organizing time division multiple access VDL Mode 4 burst: sequence of source address, burst ID, information, slot reservation, and Frame Check Sequence (FCS) fields
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