Large Number Of Base Stations Research Articles

High concurrency massive data collection algorithm for IoMT applications

The symbiotic development of machine learning (ML) and artificial intelligence (AI) is amplifying the value of the Internet of Medical Things (IoMT). Doctors are able to reach actionable conclusions faster and more reliably when dealing with large volumes of streaming data from networked medical devices. However the Internet of Things (IoT) or sensor network has a large number of base stations transmitting data to the data center server, the data center server will face challenges in collecting, parsing, and processing data. Based on the existing technical solutions, when the number of wireless sensor network base stations is large, the data collection of the IoMT system will have a concurrent bottleneck, which will cause the data collection failure and have a catastrophic impact on the application of the IoMT. This paper proposes a highly concurrent and massive data collect algorithm for IoMT applications. This algorithm uses the principle of separation of reception and processing, distributed parallel processing and multi-threading technology, and combines the highly concurrent data transmission channel provided by TCP/IP to provide a set of independent data receiving components. This component receives the data of the IoT base station, and then simply processes the data and puts it into the distributed message system to complete the sensor data receiving function. It also provides a data processing cluster. Each node of the cluster starts multiple data processing unit, each data processing unit separately obtains sensor data from the distributed message system, processes the data, and delivers the processing results to the application. The experimental results show that the algorithm proposed in this paper has a high ability of parallel collection of IoMT data.

Building a cloud-based energy storage system through digital transformation of distributed backup battery in mobile base stations

Battery energy storage systems (ESS) have been widely used in mobile base stations (BS) as the main backup power source. Due to the large number of base stations, massive distributed ESSs have largely stayed in idle and very difficult to achieve high asset utilization. In recent years, the fast-paced development of digital energy storage (DES) technology has revolutionized the traditional operation and maintenance of ESSs by transforming them into digital assets, further enabling battery energy storage services, raising up a new way to achieve a much higher utilization of such kind of largely idle ESS resources. In this paper, the disruptive DES technology will be introduced and its application under the context of mobile BSs will be studied, and then a cloud-based energy storage (CES) platform is proposed based on a large scale distributed DESs to provide a new cyber-enabled energy storage service to the local utility company. A real-world case study shows the effectiveness and efficiency of the CES platform.

Semi-Autonomous Coordinate Configuration Technology of Base Stations in Indoor Positioning System Based on UWB

In the global positioning system (GPS) denied environment, an indoor positioning system based on ultra-wide band (UWB) technology has been utilized for target location and navigation. It can provide a more accurate positioning measurement than those based on received signal strength (RSS). Although promising, it suffers from some shortcomings that base stations should be preinstalled to obtain reference coordinate information, just as navigation satellites in the GPS system. In order to improve the positioning accuracy, a large number of base stations should be preinstalled and assigned coordinates in the large-scale network. However, the coordinate setup process of the base stations is cumbersome, time consuming, and laborious. For a class of linear network topology, a semi-autonomous coordinate configuration technology of base stations is designed, which refers to three conceptions of segmentation, virtual triangle, and bidirectional calculation. It consists of two stages in every segment: Forward and backward. In the forward stage, it utilizes the manual coordinate setup method to deal with the foremost two base stations, and then the remaining base stations autonomously calculate their coordinates by building the virtual triangle train. In the backward stage, the reverse operation is performed, but the foremost two base stations of the next segment should be used as the head. In the last segment, the last two base stations should be used as the head. Integrating forward and backward data, the base stations could improve their location accuracy. It is shown that our algorithm is feasible and practical in simulation results and can dramatically reduce the system configuration time. In addition, the error and maximum base station number for one segment caused by our algorithm are discussed theoretically.

Localization Approach Based on Ray-Tracing Simulations and Fingerprinting Techniques for Indoor–Outdoor Scenarios

The increase of the technology related to radio localization and the exponential rise in the data traffic demanded requires a large number of base stations to be installed. This increase in the base stations density also causes a sharp rise in energy consumption of cellular networks. Consequently, energy saving and cost reduction is a significant factor for network operators in the development of future localization networks. In this paper, a localization method based on ray-tracing and fingerprinting techniques is presented. Simulation tools based on high frequencies are used to characterize the channel propagation and to obtain the ray-tracing data. Moreover, the fingerprinting technique requires a costly initial learning phase for cell fingerprint generation (radio-map). To estimate the localization of mobile stations, this paper compares power levels and delay between rays as cost function with different distance metrics. The experimental results show that greater accuracy can be obtained in the location process using the delay between rays as a cost function and the Mahalanobis distance as a metric instead of traditional methods based on power levels and the Euclidean distance. The proposed method appears well suited for localization systems applied to indoor and outdoor scenarios and avoids large and costly measurement campaigns.

A QoS-Based Cross-Tier Cooperation Resource Allocation Scheme Over Ultra-Dense HetNets

An ultra-dense network (UDN) can increase the system throughput by deploying a mass of low-power nodes and can greatly increase the spectral efficiency and energy efficiency at local hot spots. However, due to the random deployment of a large number of base stations (BSs), severe inter-cell interference may occur, which hinders the development of resource allocation technology, especially on the computational complexity. In this paper, we propose a quality of service (QoS)-based cross-tier cooperation transmission scheme over the UDN. In order to mitigate the interference and improve the entire network throughput, a non-convex problem is formulated. To solve this problem, first, we define the cooperation signal-to-interference-plus-noise ratio (SINR) threshold that represents the ratio of transmission power of macro BS and SBS, and we utilize the stochastic geometry theory to analyze the effect of cooperation SINR threshold on the number of user equipment. Then, we use the dedicated channel to decrease the cross-tier interference according to the fractional frequency refused mechanism. To reduce the computational complexity, this resource allocation scheme is divided into two parts, i.e., subcarrier allocation and power allocation, and we also consider the QoS requirement. The simulation results verify that our proposed scheme has better performance than the other two existing algorithms while QoS is guaranteed.

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

Optimal matching between energy saving and traffic load for mobile multimedia communication

SummaryOptimizing cell locations of cellular networks is one of the most fundamental problems of network design. However, in order to meet a growing appetite for mobile data services, a large number of base stations are being deployed, which leads to tremendous energy consumption in cellular networks. This augmentation increases not only the system's capital and operational expenditure (CAPEX/OPEX) for mobile operators but also CO2 emissions. Besides the issue of meeting overwhelming traffic demands, network operators around the world now realize the importance of managing their cellular networks in an energy‐efficient manner. In this paper, we develop a self‐organizing framework for energy saving in orthogonal frequency‐division multiple‐access–based cellular access networks. We consider three different objectives, namely, coverage maximization, overlap minimization, and power consumption minimization, which is different from all existing works on energy saving in cellular networks.

Effect of gain contouring in erbium-doped fiber amplifiers on bit error rate performance of wavelength-division multiplexing-based radio over fiber links

Radio over fiber (RoF) systems use a large number of base stations (BSs) and a number of central stations (CSs), which are interlinked together to form the network. RoF systems use multiple wavelengths for communication between CSs or between CSs and BSs to facilitate the huge amount of data traffic due to the multiple services for a large number of users. When erbium-doped fiber amplifiers (EDFAs) are used as amplifiers in such wavelength-division multiplexed systems, the nonuniform gain spectrum of EDFAs causes instability to some of the channels while providing faithful amplification to other channels. To avoid this inconsistency, the gain spectrum of the amplifier needs to be uniform along the whole usable range of wavelengths. A gain contouring technique is proposed to provide uniform gain to all channels irrespective of wavelength. Optical add/drop multiplexers (OADMs) and different lengths of erbium-doped fibers are used to create such a gain contouring mechanism in the optical domain itself. The effect of a cascade of nonuniform gain amplifiers is studied, and the proposed system mitigates the adverse effects caused due to nonuniform gain-induced channel instability effectively.

Optically Backhauled Moving Network for Local Trains: Architecture and Scheduling

The concept of moving cell in cellular systems has been discussed for 5G group mobility where rapidly moving platforms such as trains carry a large number of user terminals. It has been considered to employ wireless backhaul for moving cell, the problem of which is its limited and unstable bandwidth. To realize high bandwidth with wireless backhaul, a large number of base stations (BSs) are required along the railway. Therefore, this paper proposes the concept of optically backhauled moving network (OBMN) for local trains to efficiently provide backhaul links for local trains. In the OBMN, an autonomous BS (ABS) is set on the top of a train and is connected to a gateway via optical backhaul. While the user terminals onboard move, the ABS set on the train always satisfies the moving demands through high-bandwidth optical backhaul. The effectiveness of the proposed architecture and scheduling was confirmed by examining two case studies in the suburban and urban areas in Tokyo. The number of required BSs and deployment cost are reduced by half with the proposed OBMN compared with the existing static deployment.

Performance Impact of Idle Mode Capability on Dense Small Cell Networks

Very recent studies showed that in a fully loaded dense small cell network (SCN), the coverage probability performance will continuously decrease with the network densification. Such new results were captured in IEEE ComSoc Technology News with an alarming title of “Will Densification Be the Death of 5G?” In this paper, we revisit this issue from more practical views of realistic network deployment, such as a finite number of active base stations (BSs) and user equipments (UEs), a decreasing BS transmission power with the network densification, etc. Particularly, in dense SCNs, due to an oversupply of BSs with respect to UEs, a large number of BSs can be put into idle modes without signal transmission, if there is no active UE within their coverage areas. Setting those BSs into idle modes mitigates unnecessary intercell interference and reduces energy consumption. In this paper, we investigate the performance impact of such BS idle mode capability (IMC) on dense SCNs. Different from existing work, we consider a realistic path loss model incorporating both line-of-sight (LoS) and non-LoS transmissions. Moreover, we obtain analytical results for the coverage probability, the area spectral efficiency and the energy efficiency (EE) performance for SCNs with the BS IMC and show that the performance impact of the IMC on dense SCNs is significant. As the BS density surpasses the UE density in dense SCNs, the coverage probability will continuously increase toward one , addressing previous concerns on “the death of 5G”. Finally, the performance improvement in terms of the EE performance is also investigated for dense SCNs using practical energy models developed in the Green-Touch project.

Base Station ON-OFF Switching in 5G Wireless Networks: Approaches and Challenges

To achieve the expected 1000x data rates under the exponential growth of traffic demand, a large number of base stations (BS) or access points (AP) will be deployed in the fifth generation (5G) wireless systems, to support high data rate services and to provide seamless coverage. Although such BSs are expected to be small-scale with lower power, the aggregated energy consumption of all BSs would be remarkable, resulting in increased environmental and economic concerns. In existing cellular networks, turning off the under-utilized BSs is an efficient approach to conserve energy while preserving the quality of service (QoS) of mobile users. However, in 5G systems with new physical layer techniques and the highly heterogeneous network architecture, new challenges arise in the design of BS ON-OFF switching strategies. In this article, we begin with a discussion on the inherent technical challenges of BS ON-OFF switching. We then provide a comprehensive review of recent advances on switching mechanisms in different application scenarios. Finally, we present open research problems and conclude the paper.

Co and Adjacent Channel Interference Evaluation in GSM and UMTS Cellular Networks

Interference is the major limiting factor when evaluating the performance of cellular radio systems. Sources of interference could be another mobile at the same cell, a call in progress in a neighboring cell or other base stations operating in the same frequency band. Interference on voice channels causes cross talk due to an undesired transmission. On control channels, interference leads to missed and blocked calls due to errors in the digital signaling. Interference is more severe in urban areas, due to the large number of base stations and mobiles. Interference has been recognized as a major bottleneck when looking for increasing capacity and is often responsible for dropped calls. The two major types of system-generated cellular interference are co-channel interference and adjacent channel interference. Even though interfering signals are often generated within the cellular system, they are difficult to control in practice (due to random propagation effects). Even more difficult to control this interference caused out-of-band users, which arises without warning due to front end overload of subscriber equipment or intermittent inter-modulation products. In practice, the transmitters from competing cellular carriers are often a significant source of out-of-band interference, since competitors often locate their base stations in close proximity to one another in order to provide comparable coverage to customers. This paper presents study of co and adjacent channel interferences in second and third generations of cellular radio systems.

English

Energy efficiency in cellular networks has been receiving significant attention in wireless communication, because of the importance in reducing the energy consumption and maintaining the profitability of networks, in addition it makes these networks “greener”. In the traditional cellular architecture, the urban cell topography increases the capacity along with the coverage require the deployment of a large number of base stations (BSs). This approach is cost prohibitive and also increase the mobile station (MS) transmission power. An alternative, relaying techniques are expected to alleviate the coverage problem and reduce the MS transmission power. To propose a geometrical model for the energy efficient relay station (RS) placement that requires only a small number of characteristic distances and is to estimate the maximum cell coverage of a relay aided cell, given power constraints. This proposed method analyzes the path loss model based on RS to BS link and it compares both cell coverage and energy efficiency using Decode and Forward (DF) relaying schemes in line of sight conditions

A Velocity and Transmission Environment Based Handover Algorithm for Heterogeneous Networks

Heterogeneous networks have attracted a lot of attention for supporting high data rate and high mobility wireless communications. Since the base station density in heterogeneous networks is much larger than that in homogeneous networks, and the deployment of low power base stations in heterogeneous networks may be unplanned, a mobile user may see a large number of base stations simultaneously. Thus handover management in heterogeneous networks is much more challenging than that in homogeneous networks. In this paper, we address these challenges and propose a heuristic handover algorithm for use in heterogeneous networks. The proposed algorithm uses estimates of user velocity (speed and direction) and the transmission environment to improve the handover performance, i.e., the handover rate and the handover failure rate. Simulation results show that the proposed algorithm performs better than the conventional scheme in typical scenarios of heterogeneous networks.

Power Consumption and Packet Delay Relationship for Heterogeneous Wireless Networks

Heterogeneous wireless networks can improve network capacity by deploying overlapping base stations in different tiers. The better capacity can reduce packet delay but a larger number of base stations may result in a higher power consumption. In this paper, we consider a heterogeneous wireless cellular network that has multiple types of base stations with different transmission powers, signal-to-interference-ratio targets and deployment densities. This paper develops a method to determine the relationship between power consumption and packet delay. We calculate numerically the power consumptions and packet delays for various system configurations. Our results reveal that there is a trade-off between power consumption and packet delay. With the results, we may determine the minimum power consumption given a maximum packet delay requirement.

Bounds of performance measures in large-scale mobile communication networks

In this paper, we propose a new method for evaluating performance measures in a mobile communication network having a large number of base stations. Each base station has its own zone where its radio wave reaches. These zones are overlapping with neighboring zones, and handovers become possible. However, the existence of overlapping zones makes the analysis of a network difficult. To overcome this difficulty, we introduce an aggregated process on a smaller state space. For each of the important performance measures, using this aggregated process, we can construct a Markov decision problem that derives an exact upper (or lower) bound. Further, under some condition, we can specify a situation at which the upper (lower) bound is attained. This situation is analyzed with a far smaller model, and we can get the upper (lower) bound numerically or even by simulation.

Practical procedure for verification of compliance of digital mobile radio base stations to limitations of exposure of the general public to electromagnetic fields

In the last few years, society has witnessed the installation of an ever increasing number of radio base stations as a necessity for handling new capabilities and services to the large number of users. This rapid development of wireless networks, however, has induced a marked mistrustful attitude in people, who fear possible biological effects of electromagnetic emissions from mobile communications base stations. While there are guidelines on the limitation of human exposure to electromagnetic fields (emf ), there is no harmonised standard measurement procedure to evaluate compliance with the limits on exposure in the vicinity of a base station. The measurement procedure has to be practical, in view of the large number of base stations that have to be assessed, and rigorous, to guarantee that the limits on exposure are not exceeded in any accessible location within the coverage area of a base station. A rigorous but practical assessment procedure is presented and illustrated through several examples, where the important parameters and their influence on assessment accuracy are clearly identified. This method is also appropriate in a multiple frequency sources scenario.