Base Station Sites Research Articles

PUBLIC EXPOSURE TO MULTIPLE RF SOURCES IN GHANA.

This paper describes an effort to respond to the suggestion in World Health Organization (WHO) research agenda to better quantify potential exposure levels from a range of radiofrequency (RF) sources at 200 public access locations in Ghana. Wide-band measurements were performed-with a spectrum analyser and a log-periodic antenna using three-point spatial averaging method. The overall results represented a maximum of 0.19% of the ICNIRP reference levels for public exposure. These results were generally lower than found in some previous but were 58% (2.0 dB) greater, than found in similar work conducted in the USA. Major contributing sources of RF fields were identified to be FM broadcast and mobile base station sites. Three locations with the greatest measured RF fields could represent potential areas for epidemiological studies.

Comparative Screening Life Cycle Impact Assessment of Renewable and Fossil Power Supply for a Radio Base Station Site

Comparative Screening Life Cycle Impact Assessment of Renewable and Fossil Power Supply for a Radio Base Station Site

Fairness-oriented hybrid precoding for massive MIMO maritime downlink systems with large-scale CSIT

Different from conventional cellular networks, a maritime communication base station (BS) has to cover a much wider area due to the limitation of available BS sites. Accordingly the performance of users far away from the BS is poor in general. This renders the fairness among users a challenging issue for maritime communications. In this paper, we consider a practical massive MIMO maritime BS with hybrid digital and analog precoding. Only the large-scale channel state information at the transmitter (CSIT) is considered so as to reduce the implementation complexity and overhead of the system. On this basis, we address the problem of fairness-oriented pre-coding design. A max-min optimization problem is formulated and solved in an iterative way. Simulation results demonstrate that the proposed scheme performs much better than conventional hybrid precoding algorithms in terms of minimum achievable rate of all the users, for the typical three-ray maritime channel model.

СОКРАЩЕНИЕ РОСТА НАГРУЗКИ НА ТРАНСПОРТНУЮ СЕТЬ ОПЕРАТОРА СВЯЗИ НА ОСНОВЕ СИСТЕМЫ РАСПРЕДЕЛЕННОГО ХРАНЕНИЯ КОНТЕНТА

The paper focuses on networks operation based on LTE technology for multimedia transmission. It has been stated that the use of the last generation transport networks can become a constraint in the implementation of LTE technologies. To solve this problem the authors proposed using the system of distributed content storage. The problem of realization of such a system is divided into several subtasks. Since it is not cost-effective to organize a system of nodes at each base station site, the authors suggested selecting the nodes using clustering algorithms. Also, there is no need to store the entire video library, which is available to subscribers, on each node. Taking into account financial resources of the operator, the amount of cache node may be selected according to the power distribution of the video's popularity. To determine which specific videos should be stored in the cache, there has been offered the model of predicting the popularity of content. For this, the popularity of the video is considered as a time series. The article presents the approbated model of extrapolation of existing data as an example and analyzes its applicability to the described system.

In preparation towards future cellular networks: the detailed analysis of macro and micro site densification and sector densification

The next generation of cellular networks is expected to provide huge capacity, and site densification is one of the possible solution to increase the network capacity. The target of this paper is to show the impact of macro/micro site densification and higher order sectorization on signal strength, signal quality and throughput in LTE network. It also highlights the impact of site and sector densification on the cell overlapping and cell border areas. A detailed techno-economical analysis along with area power consumption and area spectral efficiency is also provided in this paper. In site densification, the intersite distance (ISD) between the base station sites is decreased, which results in strong inter cell interference. The results presented in this paper show that the spectral efficiency of the cell decreases with the site densification. However, the average area spectral efficiency increases due to a larger number of cells in the densified network. At the same time the number of cell border users overlapped by multiple servers also increases with the site and sector densification. It is shown that in one square kilometer, increasing the number of cells from 14 (3-sector site with 500 m ISD) to 693 (6-sector site with 100 m ISD) relatively improves the area spectral efficiency by 24.5 times at the cost of 49.5 times more number of cells. Almost identical power efficiency is provided with 3-, and 6-sector site. However, a higher order sectored site was found to be more cost efficient.

Incremental Deployment Aspects of beyond 4G and 5G Mobile HetNets

In this paper, we perform the analysis of cost effective capacity expansion strategies with incremental deployment aspects of the forthcoming mobile heterogeneous networks from beyond 4 th and 5 th generation. We consider different over time (up to year 2025) increasing traffic volumes in order to determine the most cost-effective capacity expansion that would minimize aggregate incremental cost. In this aspect, we determine that deployments with base stations having smaller ranges offer a lower investment risk on long term, because incremental capacity can be satisfied in smaller stages. This is especially due to the fact that the cost structure of smaller base stations is dominated by operational expenditures as compared to, in the other extreme, a new macro base station site. From this perspective, our techno-economic analysis proposes a model that would be useful to analyze the economic viability of different type of traffic growth volumes and for various forthcoming heterogeneous network configurations.

A Novel Full Path-Loss Model for a Street Crossing in Urban Microcells

Based on the wideband multi-input multi-output (MIMO), channel measurements carried out in downtown Helsinki, Finland, with 11 measurement routes at 3 base station (BS) sites, a full path-loss model including transition region is developed for urban microcells with Manhattan street blocks. The carrier frequency was 5.3 GHz with 100 MHz bandwidth. The size of a transition region is about 7–10 times of the first Fresnel radius with 15–23 m street widths. The model can continuously predict the path-loss when a mobile station (MS) is turning a street crossing from the line-of-sight (LOS) to non-LOS (NLOS) routes. Moreover, the proposed path-loss model is validated by an independent measurement carried out in downtown Oulu, Finland, for urban microcells at the same carrier frequency and bandwidth. By comparison with the measurement results obtained in both Helsinki and Oulu downtowns, it is found that the proposed path-loss model in this communication is more accurate in most of the measured routes, and it is also concise and easy to be implemented for coverage prediction in urban microcells.

A chance constrained approach for LTE cellular network planning under uncertainty

With the evolution towards 4G cellular networks, there is a need to develop new approaches for radio network planning (RNP) that can capture the technology enhancements to determine optimized locations and configurations of base station sites. Conventional RNP approaches are normally based on a deterministic link budget analysis that compensates for signal statistical variation via pre-determined power margins; this is normally followed by Monte-Carlo simulations to fine tune the planning outcome. In this work, we present a novel approach for cellular RNP that captures the uncertainty in signals and interference as part of the problem formulation leading directly to an optimized planning solution; the approach is generic and can capture signal uncertainty due to fading and dynamic resource allocation with possible extension to other adaptive system features. The approach is divided into two parts that are addressed separately using chance constrained optimization and then combined within a common framework. The first part, denoted as site selection problem, aims at selecting the minimum cardinality set of eNodeBs from a given large set, that satisfies target performance requirements. The second part, denoted as site placement problem, aims at refining the locations of the selected eNodeBs in order to further enhance the planning quality. Finally, both parts are combined within a common framework to determine the optimized number and locations of eNodeBs over a given geographical area based on a wide range of system and user parameters. A divide and conquer approach is also proposed to deal with the complexity of planning large network scenarios. Performance results are presented to highlight the effectiveness of the proposed framework with detailed analysis and verification via Monte-Carlo simulations.

Development of Base Transceiver Station Selection Algorithm for Collocation Arrangement

Placement of base transceiver station (BTSs) by different operators on a particular site as collocation site, so as to save cost and reduce the number of people who are at risk of radiation in BTSs located places as compared to each operator having different BTSs is the new trend in Nigeria telecommunication industries development. Collocation of base stations is much safer when compared to scattered base station telecommunication operators because of the radiations. Although the International Commission on Non-Ionizing Radiation Protection (ICNIRP) viewed that the presently existing scientific verification that prolonged contact with low frequency magnetic fields is more often than not connected with an increased danger of childhood leukaemia is too frail to form the basis for exposure guidelines. This work includes the study, analysis and proposal of a collocation scheme based on collected data of the number of BTS already sited in University of Ilorin, Ilorin, Nigeria as a case study. A drive test conducted with Transmission Environmental Monitoring System (TEMS) equipment was carried out on the existing BTSs, and a linear algorithm optimization program based on the spectral link efficiency of each BTS was developed, the output of this site optimization gives the selected number of base station sites to be used for the collocation arrangement, and the BTSs site with the best spectral link efficiency are selected in accordance with the output of the site optimization for the collocation. http://dx.doi.org/10.4314/njt.v34i3.16

State-of-the-Art Business Performance Evaluation of the Advanced Wireless Heterogeneous Networks to be Deployed for the “TERA Age”

This article originally presents a conceptual model to assess the business performance of the future advanced wireless and mobile heterogeneous network aiming to preserve enormous broadband demand of the so called "TERA age" in which a monthly usage will be expressed in terabytes and average data rates of 1.0 Gbps per single user. During the assessment from techno-economic perspective, in addition to the level of the user demand, we also take into account the wall penetration losses, density of existing/new base station sites and the recent improvements in cost of the hierarchical cell structures. We consider a spectral efficiency relevant for the forthcoming advanced radio access technologies like: 4G LTE-Advanced or LTE-A (Long Term Evolution Release 10 and beyond), 5G cellular systems deployed in the millimeter-wave (mmW) bands and high-capacity wireless local area network (WLAN) standards like IEEE 802.11ac/ad. In order to compare the achievable profit margins of various network architectures, through extensive network dimensioning for the dense-urban environment and considering the total network cost in present value, we determine the cost-efficient capacity expansion strategies for the mobile network operators by means of proper relation of the production cost per transferred data to the revenues. The findings show that the future micro base stations equipped with 5G mmW radio access technology and WLAN equipped with IEEE 802.11ac access points, can be a guarantee for the business sustainability of outdoor operations. For the highly demanding office environments the most cost-efficient solutions are the pico 5G mmW systems placed inside the buildings together with the IEEE 802.11ad enabled access points. The infrastructure cost is most elastic to a decrease of the unit cost per macro and micro base stations from one side and the capacity and coverage increase of the 5G and WLAN systems form other side. In the cases of the capacity over-provisioning, we determine the principles to provide guaranteed quality of service in terms of data rates to particular number of users.

Experimental Assessment of Specific Absorption Rate Using Measured Electric Field Strength in Benson Idahosa University and Environs

There has been growing concern in Nigeria and even the world at large that exposure to radiation from base stations and mobile handsets could lead to increased risk of illnesses such as cancer and may adversely affect cognitive functions like concentration and may cause memory loss, headaches, dizziness and epilepsy among others. In the present paper, the Assessment of RF radiation in the far-field from selected mobile base station sites in BIU and environs, Benin City, Nigeria has been carried out using a handheld three-axis radio frequency meter (EMF meter) for measurement of Electric field. The meter is a broad band device for monitoring high frequency radiation in range of 50 MHz to 3.6GHz. It is used in three-axis (isotropic) measurement mode. The electric field strength of RF radiation within a radial distance of the range 0- 100m was measured with the RF meter. The average values of the Specific absorption rate (SAR) for the general public was estimated from the measured electric field strength and the values gotten were compared with International commission on Non-ionizing radiation. Results shows that the values of the SAR for the eighth base stations selected for the study are within the range of 0.00010W/Kg- 0.0012W/Kg. These values are quite lower than the limit by International Commission on Non –ionizing Radiation Protection (ICNIRP) which is 0.08W/Kg for the whole body average SAR. This may indicate that there is no significant health risk for the general public that are always the vicinity of the Far field of the selected base stations for the various mobile service provider the area.

Performance Analyses of Renewable and Fuel Power Supply Systems for Different Base Station Sites

Base station sites (BSSs) powered with renewable energy sources have gained the attention of cellular operators during the last few years. This is because such “green” BSSs impose significant reductions in the operational expenditures (OPEX) of telecom operators due to the possibility of on-site renewable energy harvesting. In this paper, the green BSSs power supply system parameters detected through remote and centralized real time sensing are presented. An implemented sensing system based on a wireless sensor network enables reliable collection and post-processing analyses of many parameters, such as: total charging/discharging current of power supply system, battery voltage and temperature, wind speed, etc. As an example, yearly sensing results for three different BSS configurations powered by solar and/or wind energy are discussed in terms of renewable energy supply (RES) system performance. In the case of powering those BSS with standalone systems based on a fuel generator, the fuel consumption models expressing interdependence among the generator load and fuel consumption are proposed. This has allowed energy-efficiency comparison of the fuel powered and RES systems, which is presented in terms of the OPEX and carbon dioxide (CO2) reductions. Additionally, approaches based on different BSS air-conditioning systems and the on/off regulation of a daily fuel generator activity are proposed and validated in terms of energy and capital expenditure (CAPEX) savings.

Nobel Approach of Power Feeding for Cellular Mobile Telephony Base Station Site: Hybrid Energy System

The problem of providing energy to remotely located systems is a serious concern for the telecom industry, specially powering the mobile telephony towers in rural areas, which lacks quality grid power supply. The feasible solution looks to be in the form of omnipresent and technically viable alternative renewable energy based stand alone hybrid system. In order to meet sustained load demands during varying natural conditions, different energy sources and converters need to be integrated with each other. This paper presents and explores the possibility of putting hybrid energy system for powering cellular mobile base station sites. Looking at Indian weather conditions, the most feasible configuration is the stand alone PV/Wind Hybrid Energy System with diesel generator as a backup for cellular mobile telephony base station site. This system will be more cost effective and environmental friendly over the conventional diesel generator based systems in near future.

Spectrum Auctions in Turkey: Recent Developments and a Critical Assessment

This paper aims to provide a snapshot of the Turkish mobile market and evaluation of the auction process in mobilemarket. Turkey with a mobile coverage rate of 99.65% provided by more than 90 thousand base station sites constitutes a good example for mobile market in Europe. This rate is among the best coverage rates throughout Europe. Examples from other countries are also presented as a way of comparison and reaching conclusions for policy makers and practitioners. The use of auctions to enhance allocative efficiency of a scarce resource such as telecom spectrum is vital. However, the desired efficiencies shall not be realized unless the auction design and spectrum man agement policies are both optimal. Thus, a model of spectrum auctions is developed for the purpose of this study as a contribution to the literature. The model is based both on earlier experiences of Information and Communication Technologies Agency of Tur key and conclusions drawn from the literature. The model suggests a straightforward roadmap and flowchart for the policy makers.

ENERGY OPTIMIZATION AT MACRO BASE TRANSMITTER STATION SITE LOCATED IN NEMBE (BAYELSA STATE), NIGERIA

This paper explores the best energy options by which optimized energy solution for a given GSM base station site locatied in Nembe can be made. The concept of hybridizing renewable energy sources is that the base load is to be covered by available renewable source(s) and other intermittent source(s) should augment the base load to cover the peak load of the base station site. The study is based on modeling, simulation, and optimization of the hybrid energy system located in Nembe (Bayelsa state), Nigeria. The patterns of load consumption by mobile base stations in Nembe are studied and modeled suitably for optimization using the Hybrid Optimization Model for Electric Renewables (HOMER) software. Various renewable/alternative energy sources, energy storage, and their applicability in terms of cost and performance, as well as a diesel generator were discussed. The proposed hybrid [(solar, wind & hydro) + DG] system was simulated using the model which results in eight different topologies: (solar, wind & hydro) + DG, (solar & hydro) + DG, (wind & hydro) + DG, hydro only + DG, (solar & wind) + DG, solar only + DG, wind only + DG, and DG. Total economic costs [net present cost (NPC)] and the environment impact (pollutant emissions in tons of CO2) generated are used as indices for measuring the optimization level of each energy solution, and the option with the highest optimization value is considered to be the best energy solution for the base station site. The quantitative results of the study (as reported here) show that the hybrid power system can be more cost-effective and environmentally friendly in providing energy to a GSM base station site than diesel generators.

A Cost Modeling of High-capacity LTE-advanced and IEEE 802.11ac based Heterogeneous Networks, Deployed in the 700 MHz, 2.6 GHz and 5 GHz Bands

In this paper we develop “state-of-the-art” cost model of the heterogeneous wireless networks in order to determine the most cost effective radio network deployment as a function of extreme demand levels of more than 100 GB per user and month. We perform comparative analysis by consideration of the advanced radio access technologies like LTE-Advanced and IEEE 802.11ac Wi-Fi standard. Our analysis especially contributes to the assessment of the benefits when operating LTE-Advanced technology on the forthcoming “Digital Dividend II” band. The outcome of the cost model gives the proper assessment of the total investment needed to serve certain area, using bands ranging from 700MHz and up to 5GHz. The key finding is that the small cell solutions, like femto cells and Wi-Fi, are more cost efficient when new macro base station sites need to be deployed or when very high demand levels need to be satisfied. In all other evaluated cases, results show that the importance of the spectrum size is significant in leveraging cost-capacity performance. By evaluating the economic value of a joint deployment of small and macro cells, we determine that instead of investing in additional spectrum or deploying denser network, mobile operators could compensate the indoor wall penetration losses by femto or Wi-Fi sites.

Optimal Operational Strategy for PV/Wind-Diesel Hybrid Power Generation System with Energy Storage

Telecommunications industry requires efficient, reliable and cost-effective hybrid power system as alternative to the power supplied by diesel generator. This paper proposed an operational control algorithm that will be used to control and supervise the operations of PV/Wind-Diesel hybrid power generation system for GSM base station sites. The control algorithm was developed in such a way that it coordinates when power should be generated by renewable energy (PV panels and Wind turbine) and when it should be generated by diesel generator and is intended to maximize the use of renewable system while limiting the use of diesel generator. Diesel generator is allocated only when the demand cannot be met by the renewable energy sources including battery bank. The developed algorithm was used to study the operations of the hybrid PV/Wind-Diesel energy system. The control simulation shows that the developed algorithm reduces the operational hours of the diesel generator thereby reducing the running cost of the hybrid energy system as well as the pollutant emissions. With the data collected from the site, a detailed economic and environmental analysis was carried out using micro power optimization software homer. The study evaluates savings associated with conversion of the diesel powered system to a PV/Wind-Diesel hybrid power system.

Assesment of Carbon Credits for Power Generation Systems at GSM Base Station Site

Electricity production is often a source of CO2 emissions, for instance when fossil fuel is combusted in power plants. Therefore the root cause of pollution coming from telecommunication industry is the source of energy (diesel genset) the network operators used in running their Base station sites. Energy consumption of using diesel to power base station by telecom networks is a contributor to global greenhouse gas (GHG) emissions. This paper presents the comparative carbon credits of hybrid (PV/wind/hydro/Diesel) power systems for base station site. The assessment is based on theoretical model of the power stations using Hybrid Optimization Model for Electric Renewables (HOMER) software. The proposed Hybrid (Solar, Wind & Hydro) + DG system was simulated using the model which results in eight different topologies: Hybrid (Solar, Wind & Hydro) + DG, Hybrid (Solar & Hydro) + DG, Hybrid (Wind & Hydro) + DG, Hydro only + DG, Hybrid (Solar & Wind) + DG, Solar only + DG, Wind only + DG, DG. From the simulation results, it is shown that the designed Hybrid PV/wind/hydro/Diesel system has the highest carbon credits of $14509.16 relative to the case of a diesel-only system of zero. Details of the comparisons are presented.

Potentials of Optimized Hybrid System in Powering Off-Grid Macro Base Transmitter Station Site

This paper explores the possibility of hybridizing the diesel generator source system with renewable energy sources and demonstrate the potential of renewable energies to replace (partially) diesel as a source of power for mobile base station sites. The concept of hybridizing the diesel generator is to reduce both the operating cost and the quantity of different air pollutants. The patterns of load consumption by mobile base station are studied and suitably modeled for optimization using Hybrid Optimization Model for Electric Renewables (HOMER) software. The proposed Hybrid (Solar & Hydro) + DG system was simulated using the model which results in four different topologies. The solution with the highest optimization value is considered to be the best energy option (solution) for the Base Station Site. From the simulation results, the PV/Hydro-Diesel system solution has the highest optimization value. It saves $15,961,777 and 70.553 tonnes of CO 2 when compared with diesel only.

셀 경계 단말의 성능 향상을 위한 회전성 빔 방향 패턴의 활용

셀룰러 이동통신 시스템의 용량과 커버리지를 향상시키기 위한 많은 연구 결과들이 시스템에 적용되었지만, 셀 경계에서의 심각한 성능 열화는 여전히 단말 전송률의 더 나은 향상을 가로막는 주요한 요인으로 남아있다. 3GPP (Third Generation Partnership Project)의 LTE-A (Long Term Evolution-Advanced) 표준에서는 협력적 전송 (CoMP, coordinated-multipoint transmission reception)과 ICIC (inter-cell interference coordination)와 같은 진보된 기술들이 셀 경계 성능 열화 문제를 해결하기 위해 소개되었다. 본 논문에서는 다수개의 빔 방향 패턴 (BDP, beam direction pattern)을 활용하여 셀 경계 단말들의 성능을 향상시킬 수 있는 방안을 제안한다. 다수개의 빔 방향 패턴은 기지국에 설치된 복수 계층 안테나 어레이를 사용해 구현될 수 있다. 고정된 빔 패턴을 갖는 기존의 3섹터 안테나와 비교해서, 제안하는 방식은 다수개의 BDP들이 시간상에서 회전하면서 신호를 전송하게 된다. 이를 통해 셀 또는 섹터 경계에 위치하는 특정 단말들이 기지국으로부터 전체 전송 시간에 걸쳐 나쁜 성능의 신호를 수신하게 되는 상황을 억제함으로써, 해당 단말들의 수신 신호 품질을 향상시킬 수 있다. 성능 평가 결과는 제안하는 방식이 기존 3섹터 전송 방식에 비해 평균 단말 전송률 측면에서 하위 5% 단말에서 약 171% 향상된 성능을 나타냄을 보여준다.