Electromagnetic Compatibility Between International Mobile Telecommunications System and Aeronautical Telemetry System in the 1429–1518 MHz Frequency Band Sarunas Oberauskas Vidas Kalesinskas Mindaugas Zilinskas Evaldas Stankevicius Department of Radio Institute of Applied Institute of Applied Department of Computer Science Communications Electrodynamics and Electrodynamics and and Communications Communications Regulatory Telecommunications Telecommunications Technologies Authority of the Republic of Vilnius University Vilnius University Vilnius Gediminas Technical Lithuania Vilnius, Lithuania Department of Radio University Vilnius, Lithuania [email protected] Communications Vilnius, Lithuania [email protected] Communications Regulatory [email protected] Authority of the Republic of Lithuania Vilnius, Lithuania [email protected] Abstract—this paper presents the co-channel compatibility accordance with Resolution 223 (Rev.WRC-15). CEPT has also analysis between Aeronautical Mobile Telemetry system (ATS) issued the ECC Decision (17)06 on “the harmonised use of the and International Mobile Telecommunications system (IMT) in frequency bands 1427-1452 MHz and 1492-1518 MHz for the frequency band 1427-1518 MHz. IMT are developing at Mobile/Fixed Communications Networks Supplemental staggering rates and mobile operators always search for new Downlink (MFCN SDL)” and amended ECC Decision 13(03) possible frequency bands to expand their mobile and fixed on “the harmonised use of the frequency band 1452-1492 MHz communication networks (MFCN) and 1427-1518 MHz frequency for Mobile/Fixed Communications Networks Supplemental band is attractive due to the qualified radio propagation Downlink (MFCN SDL)”. conditions. However this band is already operated by other technologies, such as aeronautical networks, radio relay, All previous studies on this matter have attempted to define broadcasting networks, in the neighbouring countries. Co-channel the criteria for protection of the ATS and the trigger distances to and adjacent channel electromagnetic compatibility have to be initiate coordination. However these studies were mainly based evaluated. Electromagnetic compatibility between ATS and IMT on very conservative approaches which would likely lead to is one of the most sensitive issues regarding the decision to identify overprotection. The purpose of this paper is to determine a this band to IMT. This paper was conducted to compare two protection criteria methods, i.e. I/N and C/(I+N). protection criterion acceptable for practical purposes [5], [6]. Keywords—aircraft navigation; 4G mobile communication; This paper investigates and compares two possible ways to electromagnetic compatibility; interchannel interference, evaluate the electromagnetic compatibility in co-channel UHF propagation; UHF communication operation between MFCN BS transmitter and ATS ground station receiver based on two protection criteria methods – I/N I. INTRODUCTION and C/(I+N). In general, when the information is only available In today's world radio frequencies are being increasingly about system sensitivity, I/N criteria could be used. In cases used. There is a growing mobile technology development, thus where information is also available on the link budgets for increasing demand for radio frequencies to mobile services [1], telemetry system, appropriate way to define permitted levels of [2]. Mobile operators are often faced with the problem of interference would be the C/(I+N) method. spectrum scarcity. Companies have the resources to expand their The paper investigates and proposes the more efficient networks, but it becomes increasingly difficult to avoid approach (more efficient use and share of spectrum) to evaluate interference between adjacent stations due to ever growing the electromagnetic compatibility in co-channel operation density of wireless apparatus [3], [4]. between MFCN BS transmitter and ATS ground station receiver At World Radiocommunication Conference in 2015 (WRC- – the resource of frequencies are limited and better 15), the frequency bands 1427-1452 MHz and 1492-1518 MHz understanding of maximum interference limits would lead to were identified globally for IMT in Radio Regulations (RR) in more developed radio services in each country. 978-1-7281-9779-1/20/$31.00 ©2020 IEEE Authorized licensed use limited to: Vilnius Gediminas Technical University. Downloaded on August 03,2020 at 15:59:45 UTC from IEEE Xplore. Restrictions apply. II. TECHNICAL CHARACTERISTICS OF ATS SYSTEM territory. Thus, in the course of research, the scenario of the Tracking-type antenna system – main technical interference from the IMT BS should take into account the effect implementation of the ground station ATS works only on of interference towards both the main and side lobes of the receiving data from the tested aircraft by slowly tracking the antenna pattern of the ATS station. movement of the aircraft. In this case, ATS ground station III. TECHNICAL CHARACTERISTICS OF MOBILE SYSTEM antenna pattern is according to the Recommendation ITU-R M.1459-0 [7]. The characteristics of mobile service systems are according to Report ITU-R M.2292-0 [9] and are extracted in Table II. Radar-type antenna system – another distinctive feature of the aeronautical mobile telemetry system is the use of pulse- For the analysis in this paper the channel bandwidth of 5 code signals, which allows in some cases to partially combine MHz will be considered, however other channel bandwidth the functionality of radar and ATS. Therefore, ATS stations can values also may be under consideration. have as a separate functional implementation and be an additional component of radar equipment. In particular, the TABLE II. MFCN SYSTEM CHARACTERISTICS reflector-type radar antenna and separate components of the radar feeder system are used both by the radar and by the ATS IMT base station (BS) characteristics station. In this operating mode the data from the tested aircraft Cell radius 4.75 km is received by synchronised rotation with radar. In this case, Antenna height 30 m ATS ground station antenna pattern is according to Sectorisation 3 sectors Recommendation ITU-R M.1851-0 [8]. Downtilt 3 degrees The characteristics of aeronautical mobile telemetry system Frequency reuse 1 are provided in Table I. Recommendation ITU-R F.1336 [10] (recommends 3.1) TABLE I. ATS SYSTEM CHARACTERISTICS ka = 0.7, kp = 0.7, kh = 0.7, kv = 0.3 Parameter Value Horizontal 3 dB beamwidth: 65 Antenna pattern (see Annex 1) degrees Characteristics of ATS on-board transmitter Vertical 3 dB beamwidth: Maximum e.i.r.p., dBW 38 determined from the horizontal beamwidth by equations in Occupied bandwidth of emission, MHz 1/3/5 Recommendation ITU-R F.1336 Operation frequencies, MHz 1429-1518 Antenna polarisation Linear / ±45 degrees Maximum antenna height, m 10000 Feeder loss 3 dB Maximum antenna gain, dBi 6 Channel bandwidth 5 MHz Non-directional or low Antenna pattern on -3 dB level, º Maximum base station output directional 43 dBm power (5 MHz) Main lobe direction Low hemisphere Maximum base station antenna 18 dBi Transmission path length, km up to 320 gain Characteristics of ATS ground (terrestrial) receiver Maximum base station output 58 dBm power/sector (e.i.r.p.) Antenna height, m 10 Polarisation linear IV. ATS SYSTEM OPERATION Thermal noise floor (kTB), dBW/5 MHz −135.98 A. Protection Criteria Noise figure, dB 7 The maximum permitted interference power level at the Maximum antenna gain, dBi 30 receiver input may be specified according to one of the two Feeder losses, dB 3 criteria [11], [12]: Antenna pattern on -3 dB level (average), Vertical pattern: 10º; º Horizon pattern: 4 • “I/N” criterion – where the maximum permitted Main lobe direction, ° Azimuth: 0-360 interference is defined in relation to the thermal noise C/N ratio, dB 13 level (I is interfering signal and N is system thermal noise power); According to the RR footnote No. 5.342, the service area of • “C/(I+N)” criterion – where the value of the maximum ATS stations operating in 1429–1535 MHz frequency band is permitted interference is defined in relation to a target limited to the national territory. As the service area is determined reduction in the receiver’s signal-to-interference-plus- by the maximum radius of the system, which in turn is limited noise ratio (C is wanted signal, I is interfering signal, N by the power budget of the link from the aircraft to the ground is thermal noise). This criterion might be appropriate if level, hence the possibility of data receiving from the aircraft is the receiver operates at some margin above its minimum determined by the flight path of the aircraft within the national sensitivity and in cases where information on the link Authorized licensed use limited to: Vilnius Gediminas Technical University. Downloaded on August 03,2020 at 15:59:45 UTC from IEEE Xplore. Restrictions apply. budgets is available. paper) and for isotropically received power involving no feeder loss. To obtain the level at the reference point of the receiver, B. Coordination Trigger antenna gain and feeder losses should be taken into account. The main goal of international cross-border coordination is to allow each of the countries a mutual and optimal use of the B. Single and Aggregate Interference Simulations radio spectrum. Different countries may wish to adopt different Due to variety of border shapes, two possible simplified approaches to cross-border coordination. borderline cases could be analysed: straight