Telecommunication Base Stations Research Articles

Experimental studies on the cooling and heating performance of a highly emissive coating

In this study, the cooling effect below ambient air temperature, heat dissipation properties and heating energy efficacy of a superomniphobic self-cleaning (SSC) highly emissive (HE) coating were systematically investigated. Except at midday, the SSC-HE coating with an extremely high solar reflectance of 0.985 showed a better cooling effect than a 10-cm-thick polyurethane insulation layer. The coating substantially reduced the interior air temperature of a well-insulated system by as much as 6.9 °C. The SSC-HE coating enabled the roof surface and room temperatures of the brick bungalow to be 3.4 and 10.2 °C below the ambient air temperature, respectively. Compared with the sunshade and spray water, the SSC-HE coating exhibited better cooling effect. The SSC topcoat allowed the battery cabinet of an HE-coated distributed telecommunication base station to remain its original sub-ambient cooling effect for a long time. Regardless of the location of the HE-coated metal facility, the ultrahigh emissivity of the coating enabled it to exhibit excellent heat dissipation performance during both day and night, even under adiabatic conditions. Additionally, under identical room temperature settings, the HE-coated electric oil heater not only showed faster heating but also had heating energy efficiency of 5.9 % and 4.4 % relative to heaters coated with aluminium- and black paints, respectively. Under identical heating power consumption levels, compared to black paint-coated heater, the HE-coated heater endowed the surrounding environment with a higher equilibrium air temperature, improving the thermal comfort of the indoor environment.

Micro-environment strategy for efficient cooling in telecommunication base stations

The cooling systems of telecommunication base stations (TBSs) primarily rely on room-level air conditioners. However, these systems often lead to problems such as messy airflow, hot spots, and excessive energy consumption. With the rapid development of 5G technology, the integration and power density of communication equipment continue to increase, exacerbating these problems. To address these issues, a micro-environment strategy has been developed. This strategy combines cabinet-level airflow components with unique multi-adjustable-vent air conditioners(MAVACs), which are suitable for the co-deployment of various high power density communication equipment with different airflow patterns in TBSs. An experimental study was conducted to evaluate the cooling performance of the proposed MAVAC, and CFD simulation was carried out to investigate the temperature distribution and airflow patterns using a typical TBS in China that has implemented the micro-environment strategy. The results demonstrate that the micro-environment strategy effectively separates the cold air and hot air, preventing the occurrence of hot spots. The maximum return air temperature of MAVACs was found to be 38.6℃. Additionally, the energy efficiency ratio of the MAVAC system increases by approximately 20 % when the return air temperature is raised from 35℃ to 40℃. This study is expected to contribute to energy savings in TBSs and the successful construction of 5G networks.

Collaborative learning-based inter-dependent task dispatching and co-location in an integrated edge computing system

Recently, several edge deployment types, such as on-premise edge clusters, Unmanned Aerial Vehicles (UAV)-attached edge devices, telecommunication base stations installed with edge clusters, etc., are being deployed to enable faster response time for latency-sensitive tasks. One fundamental problem is where and how to offload and schedule multi-dependent tasks so as to minimize their collective execution time and to achieve high resource utilization. Existing approaches randomly dispatch tasks naively to available edge nodes without considering the resource demands of tasks, inter-dependencies of tasks and edge resource availability. These approaches can result in the longer waiting time for tasks due to insufficient resource availability or dependency support, as well as provider lock-in. Therefore, we present EdgeColla, which is based on the integration of edge resources running across multi-edge deployments. EdgeColla leverages learning techniques to intelligently dispatch multi-dependent tasks, and a variant bin-packing optimization method to co-locate these tasks firmly on available nodes to optimally utilize them. Extensive experiments on real-world datasets from Alibaba on task dependencies show that our approach can achieve optimal performance than the baseline schemes.

Experimental Study on the Impact of Lubricant on the Performance of Gravity-Assisted Separated Heat Pipe

Gravity-assisted separation heat pipes (GSHPs) are extensively utilized in telecommunications base stations and data centers. To ensure year-round cooling, integrating GSHPs directly with a vapor compression refrigeration system is a viable solution. It is unavoidable that the refrigeration system’s lubricant will infiltrate the heat pipe loop, thereby affecting its thermal performance. This paper examines the performance of a GSHP, which features a water-cooled plate heat exchanger as the condenser and a finned-tube heat exchanger as the evaporator, when the working fluid (R134a) is contaminated with a lubricant (POE, Emkarate RL-46H). The findings are compared with those from a system free of lubricant. The experimental outcomes indicate that the presence of lubricant degrades the heat transfer efficiency, particularly when the filling ratio is adequate and no significant superheat is observed at the evaporator’s outlet. This results in a 3.86% increase in heat transfer resistance. When the charge of the working fluid is suboptimal, the average heat transfer resistance remains relatively constant at a 3% lubricant concentration yet increases to approximately 5.27% at a 4–6% lubricant concentration, and further to 12.32% at a 9% lubricant concentration. Concurrently, as the lubricant concentration fluctuates between 3% and 9%, the oil circulation ratio (OCR) varies from 0.02% to 0.11%.

Deployment Protection for Interference of 5G Base Stations with Aeronautical Radio Altimeters.

In this manuscript, we present a novel deployment protection method aimed at safeguarding aeronautical radio altimeters (RAs) from interference caused by fifth-generation (5G) telecommunication base stations (BSs). Our methodology involves an integrated interference model for defining prohibited zones and utilizes power control and angle shutoff methods to mitigate interference. First, to ensure reliable protection, we define both horizontal and vertical prohibited zones and investigate their variations to immunize RA against 5G interference. Second, we validate the effectiveness of the model in various operational scenarios, analyzing the influence of factors such as base station types, antenna parameters, flight altitude, and aircraft attitudes to cover a wide range of real-world scenarios. Third, to mitigate interference, we propose and analyze the power control and angle shutoff methods through simulation for the RMa prohibited zone. Our results demonstrate the efficacy of the deployment protection method in safeguarding RAs from 5G interference, providing guidance for interference protection during civil aviation operations and base station deployment near airports.

Experimental investigation on the heat transfer performance of a microchannel thermosiphon array for 5G telecommunication base stations

In response to the increasing demand for enhanced heat dissipation in 5G telecommunication base stations, an innovative heatsink solution that employs air cooling was designed in this paper, namely, the microchannel thermosiphon array. The temperature characteristics, startup behavior, and temperature uniformity were experimentally investigated under various filling ratios, heating power levels and wind speeds. The results indicate that the optimal filling ratio for the microchannel thermosiphon array is 20 %. With a liquid filling ratio of 20 % and a heating power of 80 W, the total thermal resistance of the thermosiphon is 0.28 ℃/W. An increase in input power can expedite the initiation process, aiding its transition into a stable phase of heat transfer and fluid flow, characterized by evaporative rise and condensate return. Under natural convection, the microchannel thermosiphon array has a power limit of 40 W. With a wind speed of 6 m/s, the power limit increases to 140 W, resulting in a total thermal resistance of less than 0.4℃/W and a temperature lower than 74.3 °C. The research results provide guidance for optimizing the design of 5G heat dissipation devices.

Operating parameters optimization of a thermosyphon and compressor system used in 5G TBS

The free cooling technology is an effective way to reduce the energy consumption of an increasing number of 5G telecommunication base stations. In this paper, a parallel hybrid cooling system of thermosyphon and vapor compression for free cooling used in 5G telecommunication base stations has been proposed. The energy efficiency ratio (EER) is experimentally investigated in a simulated base station under different working conditions and operating parameters. The results indicate that operating parameters such as setpoints of return air temperature, evaporator and condenser fan speeds can significantly affect the natural cooling source utilization ratio of the hybrid cooling system, thereby affecting the EER of the system. When the outdoor temperature is less than 20 °C, the variation of evaporator fan speed will have a significant impact on the operating mode of the system. An appropriate evaporator fan speed can reduce the proportion of compressor operating time to 0%. At an outdoor temperature of 15 °C, optimizing the evaporator and condenser fans speeds can improve the EER by 60% and 52%, respectively. However, when the outdoor temperature exceeds 25 °C, the system always operates in air-conditioning mode, resulting in the system's EER being minimally affected by the fans speeds. While ensuring the safe operation of communication equipment, optimizing the evaporator fan speed and setpoint temperature simultaneously can increase EER from 3.18 to 17.19.

The Importance of Renewable Energy for Telecommunications Base Stations

The Importance of Renewable Energy for Telecommunications Base Stations

Sub-ambient daytime cooling effects and cooling energy efficiency of a passive sub-ambient daytime radiative cooling coating applied to telecommunication base stations— Part 1: Distributed base stations and long-lasting self-cleaning properties

To overcome the issue of overheating and conserve cooling energy consumption, a superamphiphobic passive sub-ambient daytime radiative cooling (PSDRC) coating was extensively applied to distributed telecommunication base stations. The top surfaces of the battery and equipment cabinets coated with the PSDRC coating indicated prominent sub-ambient cooling effects regardless of the climate; this resulted in substantially lower surface temperatures compared with their counterparts. The applications of the PSDRC coating reduced the chamber interior temperature of an equipment cabinet by 10.4 °C during noon hours and by 6.0 °C before sunrise. The PSDRC-coated base stations could properly operate without air conditioners by replacing the closed door with a modified one containing an external exhaust system. The drastic decrease in the chamber interior temperature of the PSDRC base stations allowed them to conserve a considerable amount of cooling energy; this, resulted in cooling energy efficiencies between 31.7% and 64.9%. After more than one year, the surfaces of the PSDRC base station near busy city transit roads were still spotless and super non-wettable; this demonstrated the significance of the superamphiphobic self-cleaning topcoat and provided the top surfaces of the base stations in various regions with identical sub-ambient cooling effects on the initial state.

Modeling and Calculation of Power Density from Telecommunication Base Station Erected at Federal University Gusau in Sabon Gida, Bungudu Local Government Area Zamfara State, Nigeria

The rampant proliferation of telecommunication mast in our societies pose fear of radiation and increase the level of noise above the prescribed residential noise. Calculation of power density around ZM811B base station to a distance of 100m radius in step of 5m were made and a hypothetical human model was also used to further illustrate the effect of radiation at the so call safe radiation level adopted by African countries. The calculated power density from the distance of 5m to 50m away from the mast (ZM811B) in step of 5m were found to be within the range of 0.0000004507 to 0.00000004507 and from 50m to 100m in step of 10m were found to be within the range of 0.0000004507 to 0.000000001122 . From the model, human body was found to be kept in a microwave oven for s per day. Nobody will put himself and his family in an open microwave oven for nineteen minutes in a day. The argument remains that the adaptation of the body to external threat and the radiation is spread over whole day. So, the simple question here to ask is would you like to put yourself in an open microwave oven for just five minutes per day, for some years? All the calculated power density were found below the safe radiation level, thus trivial. However, the model show that even at the radiation safe level one is not safe.

Spatio-Temporal Analysis and Prediction of Mass Telecommunication Base Station Failure Events

Large-scale telecommunication systems are lifeline infrastructure in modern society. A telecommunication system typically consists of a huge number of base stations with diverse geographical locations across a country, which highly complicates maintenance operations. To allocate maintenance resource properly, it is important to have a good understanding on the failure pattern of these base stations. Statistical inference of recurrent failures of these base stations is challenging because of the large number of base stations and the spatial correlation of their failure processes. Based on eight-month failure data of telecommunication base stations in Harbin, China, we propose a customized nonhomogeneous Poisson process (NHPP) model for recurrent failure data from telecommunication systems. The model consists of two layers, where the temporal layer applies an NHPP with station-specific frailty for failures of each base station, and the spatial layer uses a multivariate lognormal distribution to characterize the correlation among the frailties. The Monte Carlo EM (MCEM) algorithm is applied to estimate parameters included in the proposed model. We demonstrate the proposed model using the Harbin telecommunication system example with 7725 base stations and 4615 failure records.

Resource-aware multi-task offloading and dependency-aware scheduling for integrated edge-enabled IoV

Internet of Vehicles (IoV) enables a wealth of modern vehicular applications, such as pedestrian detection, real-time video analytics, etc., that can help to improve traffic efficiency and driving safety. However, these applications impose significant resource demands on the in-vehicle resource-constrained Edge Computing (EC) device installation. In this article, we study the problem of resource-aware offloading of these computation-intensive applications to the Closest roadside units (RSUs) or telecommunication base stations (BSs), where on-site EC devices with larger resource capacities are deployed, and mobility of vehicles are considered at the same time. Specifically, we propose an Integrated EC framework, which can keep edge resources running across various in-vehicles, RSUs and BSs in a single pool, such that these resources can be holistically monitored from a single control plane (CP). Through the CP, individual in-vehicle, RSU or BS edge resource availability can be obtained, hence applications can be offloaded concerning their resource demands. This approach can avoid execution delays due to resource unavailability or insufficient resource availability at any EC deployment. This research further extends the state-of-the-art by providing intelligent multi-task scheduling, by considering both task dependencies and heterogeneous resource demands at the same time. To achieve this, we propose FedEdge, a variant Bin-Packing optimization approach through Gang-Scheduling of multi-dependent tasks that co-schedules and co-locates multi-task tightly on nodes to fully utilize available resources. Extensive experiments on real-world data trace from the recent Alibaba cluster trace, with information on task dependencies and resource demands, show the effectiveness, faster executions, and resource efficiency of our approach compared to the existing approaches.

MAXIMIZATION THE LATENT HEAT STORAGE UNIT (LHSU) ENERGY SAVING USING SIMULATED ANNEALING ALGORITHM

An integration between latent heat storage unit (LHSU) and an air cooler was studied to reduce the space cooling energy consumption in telecommunications base stations (TBSS). A mathematical model was developed to address the heat transfer processes within energy storage modules and air cooler. Furthermore, a solid works simulation was used to simulate the real system virtually. A simulated annealing algorithm (SA) was utilized to maximize annual energy savings ratio which was considered a performance criterion for the proposed system. The calculations included comparisons the relative errors of air and temperature difference between the optimized using simulated annealing algorithm and tested (virtual) results which were calculated for both operation modes energy charging and energy discharging. The obtained results illustrated a remarkable improvement both relative errors and annual energy savings ratio for the study case.

Long-term cooling effects and cooling energy conservation of a subambient daytime radiative cooling coating relative to a cool-white coating over distributed telecommunication base stations

A superamphiphobic self-cleaning passive subambient daytime radiative cooling (SSC-PSDRC) coating with ultrahigh solar reflectance and emissivity was applied to distributed telecommunication base stations (d-TBSs) in various climatic regions. The SSC-PSDRC surface showed remarkable PSDRC effect both in the absence and presence of heat-producing electronic equipment. After exposure to severe outdoor conditions for more than one year, the top surface of the spotless d-TBS still exhibited a strong subambient cooling effect under peak sunlight conditions, owing to the presence of the SSC topcoat. Regardless of the identical appearance, the top-surface temperature difference during the noon hours between the cool-white- and SSC-PSDRC-coated d-TBSs was as high as 24.2 °C, resulting in a chamber interior temperature decrease of the SSC-SDRC-coated d-TBSs. Consequently, the measured cooling energy consumptions of the SSC-PSDRC-coated d-TBS in Kashgar for one year and that in Panzhihua for 290 d were 1044.9 and 2083.3 kWh, respectively, both of which were underestimated. In the long term, the annual cooling energy conservations estimated using different methods correlated well with the measured value in Kashgar. After five cycles of dirt- and 2200 h of artificial accelerated weathering-resistance tests, the solar reflectance of the SSC-PSDRC coating decreased by only 0.015 and 0.023, respectively. These excellent performances were attributed to the unique molecular structure of the superamphiphobic topcoat which contained networks of –Si–O–.

On-site Energy Utilization Evaluation of Telecommunication Base Station: A Case Study of Western Uganda

Due to the widespread installation of Base Stations, the power consumption of cellular communication is increasing rapidly (BSs). Power consumption rises as traffic does, however this scenario varies from geolocation to geolocation because sites in rural and urban areas have variable traffic loads. Therefore, in order to address various power consumption issues, it is necessary to analyze these sites and offer validate data that network operators can employ. This study took into account the impact of traffic load on the energy consumption both in rural and urban locations in western Uganda because prior models did not adequately account for the impact of traffic load on both rural and urban sites. Regression models are used to examine these effects of traffic load on power consumption. Based on measurements taken for twenty-eight days in a row at six urban and rural areas, linear models have been presented. The findings showed that both rural and urban BTS were well-fitted by the suggested linear models. Depending on the layouts of the sites, it was found that energy consumption varied along with traffic, with the number of transceivers present having an impact on both the traffic load and energy consumption.

Assessment of Radiation Risk from Selected Telecommunication Base Station in Ogwashi-Uku, Delta State, Nigeria

Assessment of Radiation Risk from Selected Telecommunication Base Station in Ogwashi-Uku, Delta State, Nigeria

High-Altitude Platform Stations as International Mobile Telecommunications Base Stations: A Primer on HIBS

Mobile communication via high-altitude platforms operating in the stratosphere is an idea that has been on the table for decades. In the past few years, however, with recent advances in technology and parallel progress in standardization and regulatory bodies like 3GPP and ITU, these ideas have gained considerable momentum. In this article, we present a comprehensive overview of HIBS - High Altitude Platform Stations as IMT Base Stations. We lay out possible use cases and summarize the current status of the development, from a technological point of view as well as from standardization in 3GPP, and regarding spectrum aspects. We then present preliminary system level simulation results to shed light on the performance of HIBS. We conclude with pointing out several directions for future research.

Comparative investigation of energy-saving potential and technical economy of rooftop radiative cooling and photovoltaic systems

Building-integrated radiative cooling (RC) and photovoltaic (PV) systems are promising renewable technologies harvesting energy from outer space and the sun, respectively, and can contribute to carbon neutrality. However, due to the limited building envelope area, it is significant to compare the energy-saving potential and technical economy of these two technologies, which helps to determine the system form under different working conditions. This study establishes the thermal models for rooftop RC and PV systems to simulate their temperature, heat transfer flux, and energy-saving performance. Then the energy-saving and economic indicators for comparative investigation are proposed, in which the cooling load reduction is converted into electricity saving to be compared with PV’s electricity generation. The comparison results show that RC roof has a lower energy-saving potential than PV roof during the cooling season in Beijing, China (the energy saving ratio of RC to PV is 0.536). However, the economic cost of equivalent electricity saving during the life cycle is $0.011 and $0.034 per kilowatt-hour for RC and PV systems, respectively, indicating that RC roof is more economical. In addition, applicability analysis indicates that the total cooling capacity of RC roof throughout the cooling season is larger in western and southern China, while the energy-saving potential of PV roof is higher in western and northern China. Moreover, the effects of meteorological parameters, indoor conditions, building roof characteristics, and surface optical properties on RC and PV roofs’ performance are thoroughly analyzed. The parametric analysis shows that RC roof is suitable for buildings with high heat dissipation demand and lightweight envelope structures. It is calculated that the energy yield of the RC roof is comparable to that of the PV roof in a telecommunication base station. This study will pave the way for maximizing the energy-saving potential of limited building roofs and contribute to the efficient utilization of renewable energy.

Field study on the performance of a thermosyphon and mechanical refrigeration hybrid cooling system in a 5G telecommunication base station

The increases in power density and energy consumption of 5G telecommunication base stations make operation reliability and energy-efficiency more important. In this paper, a novel type of rack-level hybrid cooling system which combines a thermosyphon loop with a mechanical refrigeration loop was developed and applied in two parallel cabinets installed different operating powers of the communication equipment. Its performance was tested on-site in a real 5G telecommunication base station in transitional season at Wuhan city, China. Thermal safety and energy consumption under the normal and urgent operation modes were evaluated. The results showed that under the normal daily operation mode 1, communication equipment can be cooled effectively, but the power usage effectiveness value reached 1.59. Under the urgent mode 7, communication equipment can maintain safe operation for over 20 min. In view of this, five novel energy-saving operation modes 2–6 were proposed and tested. The cooling effect and energy consumption under different modes were analyzed and compared. Under the thermosyphon mode 6, the cooling system can only meet the cooling demand for one side of the cabinet when the outdoor temperature is around 20 °C. Compared to mode 1, mode 5 was recommended due to the 7–9 °C lower operating temperature and 27.3% decrease of energy consumption.

Energy-saving and economic analysis of passive radiative sky cooling for telecommunication base station in China

Energy-saving and economic analysis of passive radiative sky cooling for telecommunication base station in China