Mobile Communication Base Station Research Articles

Design methodology multi-channel antenna systems base stations of professional mobile radio communication with special configurations and types of excitation

Designing base stations of corporate mobile radio communication systems based on the schematic spatial addition of incoherent signals remains an urgent task, since the tactical and technical requirements for antenna-feeder devices are constantly increasing, while the conditions for the placement of antenna systems are usually unique, respectively, the AFD design methodology requires constant improvement. A methodology for designing multi-channel antenna systems of base stations for professional mobile radio communications with special configurations and types of excitation was developed. The work provides examples of analytical and practical application of the developed methodology.

Design of a Circular Micro-strip Patch Antenna for Improved Directivity and Gain of Mobile Communication Base Station

This study presents the design of Circular Micro-strip Patch Antenna (CMPA) for improved directivity and gain of mobile communication base station. The design incorporates a Rogger/5880 substrate material with a permittivity of 2.2, tangent angle of 0.00009 and a substrate height (thickness) of 0.98μm at a frequency of 1.65THz. Diversity Antenna Array Processing (DAAP) and Chebyshev Antenna Array (CAA) methods were used in the design. AutoCAD software and 2D data plotter were used for the diagrams and charts while Maple software was used for simulation. For angles of 0o, 30o, 60o, 90o, 120o, 150o and 180o, the array factors are 7.84dB, 7.85dB, 7.87dB, 7.88dB, 7.87dB, 7.85dB and 7.84db respectively. The results from the design demonstrated a remarkably low side lobe level of 0.01dB, indicating excellent suppression of unwanted radiation in undesired directions. Additionally, the antenna exhibits a Voltage Standing Wave Ratio (VSWR) of unity, ensuring maximum power transfer efficiency from the source to the load. Furthermore, the antenna shows a high directivity and gain of approximately 9dB, which enhances the signal strength and coverage range. The Half Power Beam-width (HPBW) and First Null Beam-width (FNBW) was measured as 300 and 600 respectively. These parameters depict the angular width of the main radiation beam and the sharpness of the beam pattern’s nulls. In all, the designed CMPA with its CAA based antenna array holds great potential for communication networks and for mobile communication base station, offering enhanced performance in terms of radiation characteristics and signal quality.

A composite system of air conditioning and heat pipes: Promising application to outdoor communication cabinet

High energy consumption is an increasingly serious problem for air conditioners in mobile communication base stations, and a composite system of the air conditioning and the heat pipe is proposed to solve the problem. The experimental data obtained in Zhengzhou City elucidated the high efficiency in energy saving. The system offers a new opportunity for wide applications in outdoor communication cabinets.

Study on an energy-saving thermal management system in outdoor base stations

In order to solve the poor heat dissipation in the outdoor mobile communication base station, especially in summer, high temperature alarm phenomenon occurs frequently, affecting the normal operation of building base band unite, this paper designs an energy-saving and efficient integrated thermal management system, which has achieved good results by applying the combined operation of heat pipe cooling and air conditioning system using the outdoor temperature switching mode. A mobile communication base station in Zhengzhou City was chosen for a pilot application. The measured results showed that the system ran stably, the temperature inside the cabinet was controlled between 12?C and 39?C with no high temperature alarm, the compressor running time was significantly reduced, the power consumption of the air conditioner was significantly reduced, and the annual power saving rate was as high as 58.63%.

The evaluation of EMI characteristics of 4G-IMT system on FAST around its RQZ

Mobile communication base stations have become ubiquitous with the popularization and development of mobile communication services. Although the Chinese government has designated a radio quiet zone (RQZ) specifically for Five-hundred-meter Aperture Spherical radio Telescope (FAST), the 4G International Mobile Telecommunications (4G-IMT) system is still heavily used to meet the communication needs around the RQZ. To assess the Electromagnetic Interference (EMI) caused by 4G-IMT base stations on the performance of FAST, this paper employs the International Telecommunication Union (ITU) deterministic radio wave propagation prediction model. The interference of 4G-IMT base stations on FAST is evaluated based on relevant parameters, such as the frequency used by both FAST and the base station, in conjunction with the FAST threshold protection requirements. The results indicate that 47.73 % of the data exceed the radio astronomy protection threshold of FAST. In addition, a field experiment was conducted to verify the accuracy of the radio wave propagation prediction method used. The root-mean-square error between the predicted value and the measured value was found to be 6.94 dB, supporting the accuracy of the predicted results. The findings of this study can help suppress interference from mobile communication services around the RQZ of FAST and optimize the electromagnetic environment around FAST.

An edge server deployment method based on optimal benefit and genetic algorithm

With the speedy advancement and accelerated popularization of 5G networks, the provision and request of services through mobile smart terminals have become a hot topic in the development of mobile service computing. In this scenario, an efficient and reasonable edge server deployment solution can effectively reduce the deployment cost and communication latency of mobile smart terminals, while significantly improving investment efficiency and resource utilization. Focusing on the issue of edge server placement in mobile service computing environment, this paper proposes an edge server deployment method based on optimal benefit quantity and genetic algorithm. This method is firstly, based on a channel selection strategy for optimal communication impact benefits, it calculates the quantity of edge servers which can achieve optimal benefit. Then, the issue of edge server deployment is converted to a dual-objective optimization problem under three constraints to find the best locations to deploy edge servers, according to balancing the workload of edge servers and minimizing the communication delay among clients and edge servers. Finally, the genetic algorithm is utilized to iteratively optimize for finding the optimal resolution of edge server deployment. A series of experiments are performed on the Mobile Communication Base Station Data Set of Shanghai Telecom, and the experimental results verify that beneath the limit of the optimal benefit quantity of edge servers, the proposed method outperforms MIP, K-means, ESPHA, Top-K, and Random in terms of effectively reducing communication delays and balancing workloads.

Optimizing Multiple Beam Patterns for 5G mmWave Phased Array Applications

In this paper, a new technique for shaping multiple beam patterns antenna arrays for 5G and beyond wireless massive MIMO communication systems is introduced. The technique aims to concentrate the radio energy in specific coverage areas with a desired shape by optimizing the excitation amplitudes and phases of the array elements. To assess the proposed technique, both genetic algorithm and particle swarm optimization are utilized to optimize the excitation amplitudes and phases of the array elements such that the required number of the beams, their shapes, their directions, their power magnitudes, and the desired sidelobe pattern can be achieved. Simulation results fully confirm the effectiveness of the proposed technique in generating optimized shaped patterns that can be suitably used for distributing the radiation powers over the coverage areas in the mobile communication base stations.

Simulation on Methanol Reformed High-Temperature PEM Fuel Cell System and the Experimental Verification

A mathematical model of the SRM-HTPEM power generation system was developed to simulate the effects of parameters such as temperature and molar water to methanol ratio on the performance of the reformer and the power stack in the system. The SRM-HTPEM power generation system was built at a mobile communication base station, and the energy efficiency of the system was 45.5% at an output power of 2.8 kW. The correctness of the simulation results was verified by experiments. It finds that increasing the reaction temperature and decreasing the weight hourly space velocity will enhance the conversion of methanol and increase the CO content in the reforming gas. Increasing the molar water to methanol ratio of the feed can improve the methanol conversion and reduce the CO content. However, if the molar water to methanol ratio is too high, the energy efficiency of the system may reduce. Appropriately increasing the operating temperature of the stack, anode hydrogen concentration and hydrogen excess ratio will increase the performance of the fuel cell.

Electromagnetic environment created by mobile communication base stations in the 5G pilot area

Introduction. In the context of 5G system integration for general public, the change of electromagnetic field background is expected. The electromagnetic field background will change in spectral composition, spatial and temporal distribution, which affects the methodological approaches of instrumental control and hygienic assessment.
 Materials and methods. In the 5G pilot area the frequency-selective, code-selective and broadband measurements were carried out for the actual and possible electromagnetic field assessment from GSM, UMTS, LTE and 5G/IMT-2020 base station at several points.
 Results. The research results have shown that the actual electromagnetic levels did not exceed 1.5 μW/cm2, the main part of actual (measured) level includes GSM and LTE base stations (1800 MHz). At some points, the main part of maximum possible electromagnetic field exposure did not exceed 8.5 μW/cm2 and created by the 5G/IMT-2020 traffic transmission beam from base station to the subscriber terminal.
 Limitations. The limitation of study is determined by the measurement conditions of 5G/IMT-2020 test operation modes in the pilot area, it is difficult to assess the actual EMF exposure from commercial networks user service.
 Conclusion. In the intensive progress of mobile communication, the frequency- and code-selective measuring instruments are necessary to improve approaches for instrumental control and evaluation for electromagnetic fields from various mobile communication, especially for 5G assessment.

Dosimetric assessment in the brain for downlink EMF exposure in Korean mobile communication networks

Because the position and direction of the human body is not fixed in an actual environment, the incidence direction of the electromagnetic field (EMF) from mobile communication base stations, WiFi access points, broadcasting towers, and other far-field sources is arbitrary. To analyze the overall health effects of radio frequency EMF exposure, the dosimetric assessment for such environmental exposures created from an unspecified number of sources in daily life, along with exposures from specific EMF sources, must be quantified. This study is aimed at numerically evaluating the time-averaged specific absorption rate (SAR) of the human brain for environmental EMF exposure in the frequency range of 50–5800 MHz. Whole-body exposure to EMFs that are evenly incident spatially is considered. By comparing the results of several incidence directions and the number of polarizations, an optimal calculation condition has been derived. Finally, based on the results measured in Seoul at the end of 2021, the SAR and daily specific energy absorption (SA) in the brains of both a child and an adult for downlink exposures from 3G to 5G base stations are reported. Comparison results of the daily brain SA for exposure to DL EMF in all 3G to 5G mobile networks and exposure to a 10-min voice call (uplink EMF) using a mobile phone connected to a 4G network show that the SA from the downlinks is much higher than that from the uplinks.

Research on 5G Network Slicing Strategy for Urban Complex Environment

Focusing on the layout of the 5G mobile communication base station in the city center, we design a 5G city network slicing strategy for the three typical application scenarios with enhanced mobile broadband (eMBB), ultrareliable low-latency communications (URLLC), and massive machine type communications (mMTC). The strategy considers multiple important network performance indicators, including user guaranteed bandwidth, maximum bandwidth limit, QoS (quality of service), link delay tolerance, and slicing throughput. The slicing strategy can greatly increase the connections of base station clients and the utilization of network resources, and effectively reduce block radio and handover radio. The simulation experiments adopt the 5G base station dataset of a coastal city layout in Zhejiang province. Our tests show that the 5G network slicing strategy has certain advantages in network transmission performance in urban complex environment. The research can provide an effective reference for 5G infrastructure construction in other cities.

The Analysis and Verification of IMT-2000 Base Station Interference Characteristics in the FAST Radio Quiet Zone

In this study, we aim to analyze the electromagnetic interference (EMI) regarding the Five-hundred-meter Aperture Spherical radio Telescope (FAST) caused by base stations in the International Mobile Telecommunications-2000 (IMT-2000) frequency band. By analyzing the frequency bands used by the transmitting and receiving devices and the surrounding environmental parameters and utilizing an approach to predicting radio wave propagation loss that is based on deterministic methods, we conclude by comparing the predicted received power at the FAST with its interference protection threshold. Our analysis demonstrates that, currently, only 55.31% of IMT-2000 base stations in the FAST radio quiet zone (RQZ) meet the protection threshold. Additionally, this article verifies the applicability and accuracy of the radio wave propagation model used in the research based on field strength measurements. Overall, this study provides valuable insights for improving the electromagnetic environment surrounding FAST and reducing the EMI caused by mobile communication base stations. It also provides corresponding analysis methods and useful suggestions for analyzing electromagnetic radiation interference in other radio telescopes.

Effects of packing fraction, lattice vibration, and bond valence on the microwave dielectric properties of low-εr garnet-type Ca3Sc2Ge3O12 ceramics

A low relative permittivity (εr) can effectively reduce the signal delay of microwave components. In this study, cubic garnet-type Ca3Sc2Ge3O12 (CSG) ceramics were prepared using a traditional solid-state reaction method. The CSG ceramic exhibited a single phase (space group: Ia-3d) with a cubic garnet-type structure. The ceramic sintered at 1375 ​°C had the best topography and presented the optimal microwave dielectric properties (εr ​= ​7.08, Q×f ​= ​34697 ​GHz, and τf ​= ​−20.37 ​ppm/°C). Furthermore, the relationship between the Q×f values and the packing fraction and covalence was discussed, and the effect of lattice vibrations on the internal dielectric loss of CSG was investigated. The internal relationship between the dielectric permittivity and lattice vibration polarization was analyzed. The bond valence of the CSG material significantly affected the τf value. The excellent microwave dielectric performance indicated that CSG ceramics are suitable for use in mobile communication base stations, satellite navigation, and radar communications.

Sintering behaviour, phase composition, microstructure, and dielectric properties of BaSm2O4 microwave ceramics

BaSm 2 O 4 was prepared by the conventional solid-phase reaction method. Single-phase dense BaSm 2 O 4 ceramic (space group: Pnam ) was obtained at 1500 °C. Crystal refinement results show that BaSm 2 O 4 ceramics have a CaFe 2 O 4 structure. The change of Q × f is explained by calculating the stack fraction and radial shrinkage of BaSm 2 O 4 ceramics. When the sintering temperature was 1500 °C, the packing fraction and radial shrinkage of the BaSm 2 O 4 ceramic reached the maximum values of 52.194% and 36%. Due to secondary recrystallization, the relative density of the ceramics increases and then decreases, reaching a maximum of 1500 °C (96.65%). In addition, the τ ƒ value is affected by SmO 6 octahedral distortion. The ceramics have the best combined dielectric properties after sintering at 1500 °C for 4 h: ε r = 10.99, Q × f = 54598 GHz, τ ƒ = −25.4 ppm/°C. BaSm 2 O 4 ceramics have good prospects for applications in the field of mobile communication base stations.

Колебательный характер окислительных процессов в крови крыс при хроническом многочастотном электромагнитном облучении от систем сотовой связи стандартов GSM, UMTS и LTE

The paper presents results of research on effects of long term continuous animals exposure to multi-frequency electromagnetic fields of the mobile communication standards (GSM, UMTS and LTE). Prooxidant and antioxidant activity was investigated in the blood of exposed Wistar rats. The animals were continuously exposed to electromagnetic fields at frequencies of 1800, 2100 and 2600 MHz with the total power density of 250 muW/cm2 (GSM-20%; UMTS-20%; LTE-60%). Peripheral blood samples were taken from the affected and control rats after the decapitation at the end of each month of exposure. Fluctuations in indices of lipid peroxidation (diene conjugates) and antioxidant activity (enzyme, catalases) were observed at all stages of the exposure. The modulation effect of prooxidant and antioxidant activity in animals blood serum is suggested to depend on the amount of formed reactive oxygen species, and it may be caused by the direct effect of electromagnetic fields. The modulation effect of long-term continuous exposure to multi-frequency electromagnetic fields of mobile communication base stations on the blood lipid peroxidation may cause unfavorable consequences, which requires further study. The obtained results indicate necessity to take into account the detected modulating effect that can affect the level of reactive oxygen species.

Influence of Spatial Selectivity of Radiation of Mobile Communication Base Stations on the Level of Electromagnetic Background Introduced by them

Radio frequency electromagnetic radiation from base stations is the main source of electromagnetic background generated by mobile (cellular) communication systems in residential areas; its intensity makes a significant contribution to the level of electromagnetic pollution of the habitat and determines the level of electromagnetic safety of the population. The previously proposed technique for estimating the average intensity of this background, based on the analysis of the territorial intensity of mobile traffic, takes into account the spatial selectivity of base station radiation in a simplified form by introducing the radiation directivity parameter U, equal to the inverse of the number of base station service sectors, assuming that the width of the main lobe of the radiation pattern is equal to the width of this sector and without taking into account the radiation directivity in the vertical plane, which determines the pessimistic nature of these estimates. The paper presents a refined analysis of the values of the parameter U for a two-level models of antenna radiation patterns, which reflects the real values of the width of their main lobes in horizontal and vertical planes, the relative levels of side lobes and the ratio of radiation power of the main and side lobes. The analysis was performed both for stationary sector antennas of cellular communication systems and for adaptive phased antenna arrays of 4G/5G systems capable of providing service using narrow beams. The analysis showed that the value of the U parameter of sector antennas is 5–15 dB less than the inverse of the number of sectors of base stations, and for narrow beams of adaptive antenna arrays, this difference reaches 20 dB. If tilt angles of main lobes of antenna radiation patterns with respect to the horizon are less than 30°, then at estimation of the average electromagnetic background intensity the inverse of their antenna gain in the main lobe can be used as the U parameter value of the spatial selectivity (directivity) of base stations radiations.

Analysis and research on the resonance of mobile phone shielding cabinet

In order to cut off the connection between the mobile terminal and mobile communication base stations or Wi-Fi, it is necessary to improve the electromagnetic shielding efficiency of the mobile phone shielding cabinet. This paper analyzes the resonant characteristics of mobile phone shielding cabinets. The test method of electromagnetic shielding has been introduced. Through Maxwell wave equation and boundary conditions, the cavity resonant frequency of every small drawer on the mobile phone shielding cabinet has been derived, and the rectangular cavity research model was established. Using the high-frequency finite element method (FEM) simulation to calculate the cut-off frequency of the first 10-order high-order mode in the cavity, the resonant standing wave field distribution of every small drawer on the mobile phone shielding cabinet has been analyzed. This paper can offer a theory instruction for the product design of mobile phone shielding.

A 3‐D ‐printed Luneburg lens antenna with consistent multibeams based on quasi‐pyramid structure

A wide-scanning dual-polarized Luneburg lens antenna based on the quasi-pyramid structure is proposed. To achieve beam consistency, 18 identical quasi-pyramid sections are employed to approximate a spherical lens antenna, and each section is divided into 12 layers. The 6-stepped gradient permittivity index is achieved by the diced ring-type periodic unit cells in accordance with the Effective Medium Theory. Each quasi-pyramid is incorporated with the same connecting structure to form an integrity. And a dielectric rod is penetrated parallelly to the center axis of the lens, thus improving the robustness of the overall structure. The radius of the whole lens is merely 0.88λ0. The spherical Luneberg lens antenna is fabricated and measured, with an impedance bandwidth of 45.5%, a measured peak gain of 15.4/15.1 dBi and a cross-polarization level of higher than 17/17.5 dB. Placing the feed antenna at different locations during the measurement, results attest that those beams possess an excellent consistency. The multibeams are able to achieve an ultra-wide beam coverage of 165°, promising it a serviceable candidate for mobile communication base stations and wireless networking.

Implications of ICNIRP 2020 Exposure Guidelines on the RF EMF Compliance Boundary of Base Stations

In March 2020, the International Commission on Non-Ionizing Radiation Protection (ICNIRP) released its new guidelines (ICNIRP 2020) on the limitation of radio frequency (RF) electromagnetic fields (EMF) exposure in the frequency range 100 kHz–300 GHz. These have taken several years to develop and include the review of the latest scientific literature. Most countries worldwide currently apply the RF-EMF exposure limits provided in the ICNIRP 1998 guidelines and are expected to align their regulations according to the recently revised limits. In this paper, the implications of the ICNIRP 2020 guidelines on the RF-EMF compliance of base stations (BSs) for mobile communications are analyzed in detail. The study covers different types of BS products, from low-power small cells to macro cell equipment, operating within different frequency bands and of relevance for 2G to 5G mobile technologies. A direct comparison of the BS RF-EMF exclusion zones (or compliance boundaries), when the ICNIRP 2020 and the ICNIRP 1998 limits are applied, is provided. Since existing and future mobile equipment infrastructure is likely to be required to comply with the ICNIRP 2020 guidelines, the paper provides useful information to mobile equipment manufacturers, mobile operators, standardization bodies and regulators.

A³PNet: Antijam and Accurate Antenna Parameters Measuring Network for Mobile Communication Base Station Using UAV

Whether the down-tilt angle of the mobile communication base station antenna is reasonable directly affects the coverage effect and communication quality of the whole network. Measurement of traditional antenna parameters mainly relies on engineers climbing the base station for manual measurements, confronting the dilemma of low measurement efficiency and a dangerous working environment. Moreover, due to the interference of the wind field in real unmanned aerial vehicle (UAV) measurement scenes, there is attitude disturbance during observation, which leads to a sharp increase in measurement error. To tackle these problems, we propose an antijam and accurate antenna parameters’ measurement framework, named A³PNet, which aims to realize fully automatic mobile communication base station antenna parameters’ measurement through UAV. Above all, for measuring in windy environment, an adaptive feature recovery module (AFRM) is presented to restore the antenna attitude while reducing the measurement error. Also, contour modulation strategy (CMS) is cooperated to smooth the deformation path and decouple the offset movement of the vertex to speed up the learning process. Go one step further, a general antenna down-tilt measurement module is proposed to replace the cumbersome numerical fitting analysis method, and it is embedded in the mainstream model to realize the task of down-tilt angle measurement. Extensive experiments over both the newly established Antenna-disturb dataset and the original Antenna-scapes dataset demonstrate the effectiveness of A³PNet. Specifically, it outperforms the state-of-the-art (SOTA) approaches by 2.40% on the Antenna-scapes dataset and 7.23% on the Antenna-disturb dataset, and meanwhile has 27.1 frames/s real-time processing speed, improving the measurement method of antenna parameters.