Base Stations In Areas Research Articles

Design of Antenna Polarization Plane for Concurrent Uplink/Downlink Drone Networks

In recent years, drones have been used in a wide range of fields, such as agriculture, transportation of goods, and security. Drones equipped with communication facilities are expected to play an active role as base stations in areas where ground base stations are unavailable, such as disaster areas. In addition, asynchronous operation is being considered for local 5G, in order to support all kinds of use cases. In asynchronous operation, cross-link interference between base stations is an issue. This paper attempts to reduce the interference caused by the drone network by introducing circularly polarized antennas against the conventional system using linearly polarized antennas. Numerical analyses are conducted to validate the effectiveness of the proposed system, where Signal-to-Interference Ratios (SIRs) are shown to be improved significantly as the numerical evaluation results. Specifically, for the scenario of only access links, in the region where conventional antenna architecture can only achieve an SIR of less than 20 dB, our proposed system applying circularly polarized antennas can almost realize an SIR of more than 40 dB. Significant improvement can be also observed in the scenario with the existence of backhaul links, where the conventional system had difficulty achieving our system design goal SIR of 16.8 dB, while the proposed antenna architecture could easily attain this goal in most regions of our evaluation ranges.

Base Station Planning Based on Region Division and Mean Shift Clustering

The problem of insufficient signal coverage of 5G base stations can be solved by building new base stations in areas with weak signal coverage. However, due to construction costs and other factors, it is not possible to cover all areas. In general, areas with high traffic and weak coverage should be given priority. Although many scientists have carried out research, it is not possible to make the large-scale calculation accurately due to the lack of data support. It is necessary to search for the central point through continuous hypothesis testing, so there is a large systematic error. In addition, it is difficult to give a unique solution. In this paper, the weak signal coverage points were divided into three categories according to the number of users and traffic demand. With the lowest cost as the target, and constraints such as the distance requirement of base station construction, the proportion of the total signal coverage business, and so on, a single objective nonlinear programming model was established to solve the base station layout problem. Through traversal search, the optimal threshold of the traffic and the number of base stations was obtained, and then, a kernel function was added to the mean shift clustering algorithm. The center point of the new macro station was determined in the dense area, the location of the micro base station was determined from the scattered and abnormal areas, and finally the unique optimal planning scheme was obtained. Based on the assumptions made in this paper, the minimum total cost is 3752 when the number of macro and micro base stations were determined to be 31 and 3442 respectively, and the signal coverage rate can reach 91.43%. Compared with the existing methods, such as K-means clustering, K-medoids clustering, and simulated annealing algorithms, etc., the method proposed in this paper can achieve good economic benefits; when the traffic threshold and the number of base stations threshold are determined, the unique solution can be obtained.

Optically Powered and Controlled Drones Using Optical Fibers for Airborne Base Stations

Mobile communication services are crucial during emergency disasters and temporary events, and future mobile communication systems should be able to provide such services. Airborne base stations using drones are highly effective as stand-in base stations in areas where the ground base stations are inoperable or at temporary event sites. However, it is difficult for conventional drones to provide mobile communication services without interruption due to flight time limitations caused by their limited battery capacity. Thus, a drone drive with a non-interrupted power supply is urgently needed. In this study, we developed an airborne base station that enables drones to be driven and maneuvered by optical fibers. We simultaneously transmitted radio frequency (RF) data signals for the airborne base station and control signals for the drone and evaluated the transmission performances of the RF signals and the controllability of the drone. Furthermore, we conducted a flight experiment on a medium-sized drone powered by optical fibers.

Environmental Pollution of Cellular Mobile Base Station in Populated Areas

Cellular mobile communication technology has grown exponentially in the last decade resulting in large number of base stations in areas at which people are living or working. All over the world, the electromagnetic pollution produced from cellular base stations erected in residential areas and its effect on the environment and human body is a problem that has been concerning the society for many years. This paper, introduces the effects of electromagnetic energy emitted cellular base stations on the biological systems of the human body. The induced electromagnetic fields (EMF), and specific absorption rate (SAR) were calculated in close proximity to cellular mobile base stations. The calculated values of SAR were compared with the most commonly used international limits. The results show that the electromagnetic radiation (EMR) exposure levels at a distance of several meters from the base station towers can cause hazardous effects to the public

Concept design and performance evaluation of UAV-based backhaul link with antenna steering

At present, cellular coverage in many rural areas remains intermittent. Mobile operators may not be willing to deploy expensive network infrastructure to support low-demand regions. For that reason, solutions for the rapid deployment of base stations in areas with insufficient or damaged operator infrastructure are emerging. Utilization of unmanned aerial vehicles (UAVs) or drones serving as data relays holds significant promise for delivering on-demand connectivity as well as providing public safety services or aiding in recovery after communication infrastructure failures caused by natural disasters. The use of UAVs in provisioning high-rate radio connectivity and bringing it to remote locations is also envisioned as a potential application for fifth-generation (5G) communication systems. In this study, we introduce a prototype solution for an aerial base station, where connectivity between a drone and a base station is provided via a directional microwave link. Our prototype is equipped with a steering mechanism driven by a dedicated algorithm to support such connectivity. Our experimental results demonstrate early-stage connectivity and signal strength measurements that were gathered with our prototype. Our results are also compared against the free-space model. These findings support the emerging vision of aerial base stations as part of the 5G ecosystem and beyond.

Joint scheduling and power control for multicasting in cellular wireless networks

We consider a cellular wireless network. Our aim is to develop adaptive-power scheduling algorithms that enable area base stations to coordinate, on a time-division basis, the transmission of multicast packets to identified client nodes, for scenarios under which a prescribed code rate is employed. Such mechanisms can be implemented by 4G long term evolution (LTE) systems using multimedia broadcast multicast services (MBMS), meshed WiFi networks, or mobile backbone based ad hoc wireless networks. We show that the joint scheduling and power control problem can be represented as a mixed-integer linear programming model, which is NP-hard. Consequently, we present three heuristic algorithms of polynomial complexity for solving the problem in a practical manner. For small network layouts, our centralized heuristic algorithm is shown to achieve a throughput rate performance that is close to that attained by the optimal scheme. All three of our heuristic algorithms are shown to yield excellent throughput rate performance behavior. The use of power adaptations, when compared with fixed transmit power operations, leads to enhanced throughput rate performance while also lowering communications energy consumption levels. Comparisons with LTE MBMS over single frequency network based schemes have shown our algorithms to offer enhanced spectral efficiency performance, while providing high client coverage.

Haematological effects of radiofrequency radiation from GSM base stations on four successive generations (F1 and #8211; F4) of albino mice, <i>Mus Musculus</i>

Aim: The aim of the study is to evaluate the haematological effects of radiofrequency (RF) radiation from Global Systems for Mobile Communication (GSM) base stations on four successive generations of albino mice Mus musculus were evaluated. Methods: Each generation of mice were exposed to the RF radiation from birth till they reproduced and blood samples collected. After the mice had given birth to the young ones and weaned off, the parent group was sacrificed and 500μl of blood was obtained. Estimation of hemoglobin concentration, white blood cell count, platelet count, red blood cell count, lymphocyte, pack cell volume (PCV) and red cell indices were carried out using electronic coulter counter. Results: The level of radiofrequency radiation around the base station was found to range between 0.6129V/m to 1.695V/m. In the successive generations of mice, a pattern of pancytosis was observed and significant increases were observed in the Packed Cell Volume, White Blood Cell Count, Platelet Count and Red Blood Cell Count. Conclusion: In the successive generations of exposed mice, a pattern of pancytosis was observed, as well as, an increase in the haemopoetic process which caused significant effects on bone marrow stem cell proliferation of differentiation. The effects of chronic exposure to radiofrequency radiations on peripheral blood parameters is found to be sufficient to apply the precautionary principle to discourage the indiscriminate location of GSM base stations in areas where prolonged exposure to radiofrequency radiations are likely to occur.

Kinematic GPS solutions for aircraft trajectories: Identifying and minimizing systematic height errors associated with atmospheric propagation delays

When kinematic GPS processing software is used to estimate the trajectory of an aircraft, unless the delays imposed on the GPS signals by the atmosphere are either estimated or calibrated via external observations, then vertical height errors of decimeters can occur. This problem is clearly manifested when the aircraft is positioned against multiple base stations in areas of pronounced topography because the aircraft height solutions obtained using different base stations will tend to be mutually offset, or biased, in proportion to the elevation differences between the base stations. When performing kinematic surveys in areas with significant topography it should be standard procedure to use multiple base stations, and to separate them vertically to the maximum extent possible, since it will then be much easier to detect mis‐modeling of the atmosphere.