A method for evaluating coexistence of LTE and radar altimeters in the 4.2–4.4 GHz band

Singh, Rohit; Peterson, Roger L.; Riaz, Ali; Hood, Cynthia S.; Bacchus, Roger; Roberson, Dennis

doi:10.1109/wts.2017.7943543

Cited by 12 publications

(7 citation statements)

References 2 publications

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“…This signal allows for the formation of some so-called unstable height pulses N u . They alternately arise and disappear when the amplitude of the difference signal passes through zero [3,11,12]. Defining the condition of the formation and the dissolution of the unstable height pulses determines the rise H F and extinction H E heights of the individual pulses:…”

Section: Difference Signal Of Fmcw Radio Altimetermentioning

confidence: 99%

“…Closer analysis of this phenomenon can observe that the process of the formation and dissolution of the unstable height of pulses is not chaotic, but has regularity. The regularity of the formation and dissolution of the height pulses is related to the change in the measured height, but their number in the range of critical height corresponds to the technical parameters of the radio altimeter [11,12].…”

Section: Simulation Of Height Pulses Creationmentioning

confidence: 99%

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Low Altitude Measurement Accuracy Improvement of the Airborne FMCW Radio Altimeters

et al. 2019

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This manuscript focuses on the analysis of a critical height of radio altimeters that can help for the development of new types of aeronautical radio altimeters with increased accuracy in measuring low altitudes. Altitude measurement accuracy is connected with a form of processing the difference signal of a radio altimeter, which carries information on the measured altitude. The definition of the altitude measurement accuracy is closely linked to the value of a critical height. Modern radio altimeters with digital processing of a difference signal could shift the limit of accuracy towards better values when the basics of the determination of critical height are thoroughly known. The theory results from the analysis and simulation of dynamic formation and the dissolution of the so-called stable and unstable height pulses, which define the range of the critical height and are presented in the paper. The theory is supported by a new method of derivation of the basic equation of a radio altimeter based on a critical height. The article supports the new theory of radio altimeters with the ultra-wide frequency deviation that lead to the increase the accuracy of a low altitude measurement. Complex mathematical analysis of the dynamic formation of critical height and a computer simulation of its course supported by the new form of the derivation of the basic equation of radio altimeter guarantee the correctness of the new findings of the systematic creation of unstable height pulses and the influence of their number on the altitude measurement accuracy. Application of the presented findings to the aviation practice will contribute to increasing the accuracy of the low altitude measurement from an aircraft during its landing and to increasing air traffic safety.

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Section: Difference Signal Of Fmcw Radio Altimetermentioning

confidence: 99%

Section: Simulation Of Height Pulses Creationmentioning

confidence: 99%

Low Altitude Measurement Accuracy Improvement of the Airborne FMCW Radio Altimeters

et al. 2019

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“…China has allocated the 4400-4500 MHz band to 5G systems; however, there is a concern that 5G systems operating in this band may cause harmful interference to aviation radio navigation operations, particularly radio altimeters, which operate in the 4200-4400 MHz band. The radio altimeter plays a crucial role in ensuring the accuracy of equipment and proper operation of aircraft [2]. The electromagnetic compatibility of both will become an important factor affecting the safe operation of aircraft.…”

Section: Introductionmentioning

confidence: 99%

Radio altimeter compatibility analysis with 5G systems

Chen,

Li,

Liu

et al. 2024

Ninth International Symposium on Sensors, Mechatronics, and Automation System (ISSMAS 2023)

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With the rapid advancement of 5G technology, the coexistence of radio altimeters and 5G systems has become increasingly significant. This study aims to investigate the impact of different flight altitudes and horizontal isolation distances on system performance in urban and rural areas, by simulating the aggregate interference of ground base stations. The simulation results reveal that there exists a compatibility issue between the 5G system and radio altimeters in the 4400-4500MHz band only if the aircraft altitude is 50m or less and the horizontal separation distance is less than 10m in urban environments and less than 6m in rural environments. Nevertheless, the levels of interference can be disregarded as they do not pose a significant threat in practical applications. These results provide valuable practical insights for the implementation of 5G technology in the aviation industry.

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“…The work of [11] proposed an analysis method to evaluate the impact of interference from RAs on long-term evolution (LTE) user equipments (UE) when RAs share the 4.2 -4.4 GHz band with LTE. However, the study did not provide conclusive findings on the feasibility of this sharing.…”

Section: Introductionmentioning

confidence: 99%

Coexistence of 5G Communication Systems With Radar Altimeters

Li,

Liu,

et al. 2024

IEEE Access

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With the growing demand for 5G, many countries have allocated additional spectrum above 3.7 GHz, potentially causing serious interference to radar altimeters operating at the 4.2-4.4 GHz band. Therefore, in this paper, a general mathematical model is proposed to estimate interference from 5G base stations to a radar altimeter which can be applied for aircraft, helicopters, unmanned aerial vehicles, satellites, and hot-air balloons. Using this model, the interference at the radar altimeter is evaluated in several environments such as rural, suburban, and urban. Two types of antennas are considered which are omnidirectional and multiple-input and multiple-output antennas (4-by-4, 8-by-8, and 16-by-16). Additionally, a power control-aided distance protection method is introduced to enable the coexistence of the 5G base stations and the radar altimeters. To validate the effectiveness of the proposed protection method, the Monte Carlo method is employed. Numerical results present the heights of the radar altimeter where the interference-to-noise ratio becomes higher than the interference protection threshold of -6 dB. In addition, it shows that the radar altimeter can coexist with the 5G base stations with the proposed protection scheme.

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A method for evaluating coexistence of LTE and radar altimeters in the 4.2–4.4 GHz band

Cited by 12 publications

References 2 publications

Low Altitude Measurement Accuracy Improvement of the Airborne FMCW Radio Altimeters

Low Altitude Measurement Accuracy Improvement of the Airborne FMCW Radio Altimeters

Radio altimeter compatibility analysis with 5G systems

Coexistence of 5G Communication Systems With Radar Altimeters

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