Future Base Station Research Articles

Intelligent Base Station Placement in Urban Areas With Machine Learning

This paper presents a time-reliable machine learning model for accurate and rapid base station placement in urban areas. Several real-world city data are used for training the machine learning model to predict parameters such as path loss values. It is developed using supervised training and multiple regressions with the use of artificial intelligence. Parameters such as coverage dimensioning, bandwidth of frequencies, building's density and height, propagation model tuning and path loss values are used to predict the locations of base stations. Once the predicted base station position is obtained, the average percentage error is calculated against the real-world data of base station that shows an accuracy of 84%. This proves that our model is a reliable tool to predict future base station locations. This model will benefit the telecommunication industries to reduce time and cost for rapid base station planning in urban areas that see frequent changes to their landscapes.

Energy-saving Scheme of 5G Base Station Based on LSTM Neural Network

As China’s new infrastructure,5G has received national and social attention. 5G promotes economic to grow rapidly. But, the high energy consumption caused by the massive deployment of 5G base stations cannot be ignored. The total annual power consumption is expected to reach 243 billion degrees when the 5G base station is fully built. In the tidal scene, some 5G base station in an idle state still power fully, which causes great power waste. The historical volume of base station business data is used to train LSTM model, and predict the future base station business. When the business is lower than the threshold, the base station will be closed to avoid unnecessary power waste. And the LSTM model prediction results fits the original data ideally. By implementing the power saving strategy, the energy consumption of the base station is reduced by 18.97 %. A single station can save 1174 degrees of electricity yearly. It can be seen that the energy saving effect is remarkable.

Ultrawideband Dual-Polarized Antenna for LTE600/LTE700/GSM850/GSM900 Application

An ultrawideband antenna is proposed for base station using loop resonator below the dual-polarized antenna. The designed loop resonator below is able to introduce new resonance to the antenna for ultrawideband operation. The energy is coupled by the loop dipole. This design can effectively enhance the bandwidth without using extra antenna space, which contributes to the multiarray arrangement in the future. Consequently, a full parameter wideband dual-polarized antenna is obtained. Simulation and measurement exhibit a wide bandwidth of 54.3% (|S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> | <; -15 dB) from 550 to 960 MHz with polarization isolation of more than 31 dB. Desirable stable radiation patterns are also obtained over the whole band. It is a good candidate for the future base station communication system, etc.

A Simultaneous Wideband Calibration for Digital Beamforming Arrays at Short Distances [Measurements Corner

Massive multiple-input, multipleoutput (MIMO) is seen as an enabling technology for 5G communication systems [1]. Future base stations (BSs) featuring massive MIMO technology are expected to be equipped with a large number of antennas with digital beamforming structures, where the signals of all the channels are independently accessible. The array radiation pattern can be controlled via setting proper complex weights to the antenna elements to, e.g., form a beam in a desired direction to overcome the unfavorable propagation loss, or to form a null in an interference signal direction to suppress unwanted signals [2]. In addition, spatial multiplexing can also be utilized to serve multiple users simultaneously over the same time and frequency resource with various precoding schemes, which enlarges the network capacity.

Alarm Prediction in Cellular Base Stations Using Data-Driven Methods

The importance of cellular networks continuously increases as we assume ubiquitous connectivity in our daily lives. As a result, the underlying core telecom systems have very high reliability and availability requirements, that are sometimes hard to meet. This study presents a proactive approach that could aid satisfying these high requirements on reliability and availability by predicting future base station alarms. A data set containing 231 internal performance measures from cellular (4G) base stations is correlated with a data set containing base station alarms. Next, two experiments are used to investigate (i) the alarm prediction performance of six machine learning models, and (ii) how different predict-ahead times (ranging from 10 min to 48 hours) affect the predictive performance. A 10-fold cross validation evaluation approach and statistical analysis suggested that the Random Forest models showed best performance. Further, the results indicate the feasibility of predicting severe alarms one hour in advance with a precision of 0.812 (±0.022, 95 % CI), recall of 0.619 (±0.027) and F1-score of 0.702 (±0.022). A model interpretation package, ELI5, was used to identify the most influential features in order to gain model insight. Overall, the results are promising and indicate the potential of an early-warning system that enables a proactive means for achieving high reliability and availability requirements.

Realtime parallel software implementation of a DS-CDMA Multiuser Detector

In this article the complexity and runtime performance of two Multiuser Detectors for Direct Sequence-Code Division Multiple Access were evaluated in two different hardware platforms. The innovation and aim is to take advantage of present parallel hardware to bring Multiuser technology to present and future Base Stations in order to increase the capacity of the overall system, to reduce the transmission power by the mobile stations and to reduce base station hardware requirements, in Universal Mobile Telecommunications System. The detectors are based on the Frequency Shift Canceller concatenated with a Parallel Interference Canceller. This detector implies the inversion of multiple identical size small matrices and because of that it is very scalable contrary to other solutions/detectors that only permit a sequential implementation despite their lower complexity. Implementations for the Time Division–Code Division Multiple Access, in two software platforms one in OpenMP and the other in CUDA were done taking into account the carrier and doppler frequency offsets (offset different for each user). The result shows that this deployment aware real-time implementation of the Multiuser Detectors is possible with a Graphics Processor Unit being three times faster than required.

Millimetre‐wave antenna with tilted beam for future base station applications

A novel flexible and reconfigurable pattern antenna, integrated with an artificial magnetic conductor (AMC) surface, operating in the 29-31 GHz millimetre-wave frequency band, is proposed. The designed antenna is a modified Yagi-Uda antenna that uses as directors loop diamond shapes, allowing the bending of the structure in an easy way at high frequencies. The AMC structure is also composed of an array of diamond loops, printed on a grounded dielectric substrate without vias. Furthermore, an equivalent circuit model that allows the estimation of the resonant frequency and reflection coefficient phase of the AMC is presented. Using a flexible substrate in designing the proposed AMC antenna, different beam-tilting angles can be obtained. Moreover, multiple pattern configurations are studied. The performance of the proposed AMC antenna is measured for flat and curved configurations. The maximum beam-tilting angle is obtained for the curved AMC antenna configuration and is equal to +32° towards the + z direction with a realised gain of 12.1 dBi. Additionally, a beam-tilting in the ± z elevation plane is achieved by integrating a single pole, double throw switching system. This method eliminates the complex steering system that uses phase shifters, which is traditional for the targeted applications.

A Dual Layered Loop Array Antenna for Base Stations With Enhanced Cross-Polarization Discrimination

This paper presents a novel dual-loop array antenna targeted at current and future base station applications. The antenna has four rectangular loops and four trapezoidal loops printed on the front and back sides, respectively, of a substrate placed above a flat square reflector. All eight loop radiators are excited simultaneously with properly designed feed networks to achieve its ±45° polarization states. The trapezoidal loops act like folded (electric) dipoles; the rectangular loops act primarily as magnetic dipoles. The combination of these two loop arrays leads to a type of magnetoelectric loop antenna that has stable directivity patterns with high cross-polarization discrimination (XPD) values across a 45.5% operational fractional bandwidth from 1.7 to 2.7 GHz. A fabricated and measured prototype confirms the simulation results and demonstrates that the half-power beamwidths in the horizontal plane vary between 63° and 70°, the XPD values are >20 dB in the boresight direction, and are >10 dB within the entire cellular coverage angular range: $-60^\circ \leq \theta \leq 60^\circ $ .

Energy estimation and optimization platform for 4g and the future base station system early-stage design

There are already several power models to estimate the power consumption of base stations at system level. However, there is so far no model that can predict power consumption of the future base station designs based on algorithms and hardware selections with insufficient physical information. We present such an energy model for typical base stations. This model can help designers in estimating, evaluating and optimizing energy/ power consumption of candidate designs in early design stages. The proposed model is verified by an LTE extreme scenario. The estimated results show that digital front-end, channel equalization and channel decoding are three major power greedy modules (consuming 39.4%, 16.3%, 13.4%) in a digital baseband subsystem. The power estimation error of the proposed power amplifier (PA) power model is 3.5% (macro cell). The major contribution of this paper is that the proposed models can rapidly estimate energy/power consumption of 4G and the future base stations (such as 5G) in early design stages with well acceptable precision, even without sufficient implementation information.

Energy saving in a 5G separation architecture under different power model assumptions

In this paper, a framework is developed to study the impact of different power model assumptions on energy saving in a 5G separation architecture comprising high power Base Stations (BSs) responsible for coverage, and low power, small cell BSs handling data transmission. Starting with a linear power model function, the achievable energy saving are derived over short timescales by operating small cell BSs in low power states rather than higher power states (termed Low Power State Saving (LPSS) gains) for single and multiple BS scenarios. It is shown how energy saving varies with different power model assumptions over long timescales in accordance with short timescale LPSS. Simulation results show that energy saving in the separation architecture varies across the six power models examined as a function of model-specific significant LPSS state changes. Furthermore, it is shown that if the architecture is based on existing small cell BSs modelled by state-of-the-art (SotA) power models, energy saving will be mainly dependent on sleep state operation. Whereas, if it is based on future BSs modelled by visionary power models, both sleep and idle state operations provide energy saving gains. Moreover, with future BSs, energy saving of up to 42% is achievable when idle state overhead is considered, while a higher saving is possible otherwise.

Design of an Energy Efficient Future Base Station with Large-Scale Antenna System

Due to the continuous increase in data demanded by end-users, an energy-efficient base station (BS) is a vital topic of interest that would not only result in a substantial economic impact on service providers, but would also reduce the carbon footprint of operating a network. In this regard, we propose the structure and systematic operation of a BS with a large-scale (LS) antenna system that can increase the energy efficiency (EE) of cellular systems. The proposed BS structure includes various power-related units, such as a central management apparatus, power controller, EE calculator, radio site-dependent parameter space (RSD-PS) and determiner. With the information provided from each unit, the decision unit determines how to adjust each component of the BS in order to maximize the EE. Extensive simulations show that the proposed BS improves the EE performance by about 83.05% relative to the reference BS.

When telecommunications networks meet energy grids: cellular networks with energy harvesting and trading capabilities

In this article, we cover eco-friendly cellular networks, discussing the benefits that ambient energy harvesting offers in terms of energy consumption and profit. We advocate for future networks where energy harvesting will be massively employed to power network elements; even further, communication networks will seamlessly blend with future power grids. This vision entails the fact that future base stations may trade some of the excess energy they harvest so as to make a profit and provide ancillary services to the electricity grid. We start by discussing recent developments in the energy harvesting field, and then deliberate on the way future energy markets are expected to evolve and the new fundamental trade-offs that arise when energy can be traded. Performance estimates are given throughout to support our arguments, and open research issues in this emerging field are discussed.

Multilevel power modeling of base station and its ICs

A new power estimation method is proposed for base station (BS) in this paper. Based on this method, a software platform for power estimation is developed. The proposed method models power consumption on different abstraction levels by splitting a typical base station into several basic components at different levels in the view of embedded system design. In particular, our focus is on baseband IC (Integrate Circuit) due to it’s the dominant power consumer in small cells. Baseband power model is based on arithmetic computing costs of selected algorithms. All computing and storage costs are calibrated using algorithm complexity, hardware architecture, activity ratio, silicon technology, and overheads on all hierarchies. Micro architecture and IC technology are considered. The model enables power comparison of different types of base stations configured with different baseband algorithms, micro architectures, and ICs. The model also supports cellular operators in power estimation of different deployment strategies and transmission schemes. The model is verified by comparing power consumption with a real LTE base station. By exposing more configuration freedoms, the platform can be used for power estimation of current and future base stations.

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.

Electromagnetic band gap‐dipole sub‐array antennas creating an enhanced tilted beams for future base station

A novel customised electromagnetic band gap (EBG)-dipole sub-array antenna with a tilted beam for future base-station applications is presented. An enhanced tilted beam for the base-station antenna is one of the safest methods to increase radio coverage area adhering to the strict power requirements. An array of four dipole-EBG elements is designed demonstrating the enhanced down-tilt beam. Each single element consists of dipole antenna mounted on a customised EBG ground plane created by connecting several unit cells of the EBG. The proposed array radiates a tilted beam in order to achieve a high directivity at fixed down-tilt angle. The array antennas are simulated, fabricated and measured. The directivity of 11 dB is measured at the angle of 28° at 3.5 GHz. This directivity is 1.9 dB higher than the reference case that uses the broadside single element. In addition, the EBG-dipole array that can be mechanically tilted is designed. The proposed array antenna exhibits acceptable impedance matching across the operational frequency band.

Resource Management for Software-Defined Radio Clouds

Software-defined radio (SDR) clouds combine SDR concepts with cloud computing technology for designing and managing future base stations. They provide a scalable solution for the evolution of wireless communications. The authors focus on the resource management implications and propose a hierarchical approach for dynamically managing the real-time computing constraints of wireless communications systems that run on the SDR cloud.

Green radio: radio techniques to enable energy-efficient wireless networks

Recent analysis by manufacturers and network operators has shown that current wireless networks are not very energy efficient, particularly the base stations by which terminals access services from the network. In response to this observation the Mobile Virtual Centre of Excellence (VCE) Green Radio project was established in 2009 to establish how significant energy savings may be obtained in future wireless systems. This article discusses the technical background to the project and discusses models of current energy consumption in base station devices. It also describes some of the most promising research directions in reducing the energy consumption of future base stations.

A Potential Transmitter Architecture for Future Generation Green Wireless Base Station

Current radio frequency power amplifiers in 3G base stations have very high power consumption leading to a hefty cost and negative environmental impact. In this paper, we propose a potential architecture design for future wireless base station. Issues associated with components of the architecture are investigated. The all-digital transmitter architecture uses a combination of envelope elimination and restoration (EER) and pulse width modulation (PWM)/pulse position modulation (PPM) modulation. The performance of this architecture is predicted from the measured output power and efficiency curves of a GaN amplifier. 57% efficiency is obtained for an OFDM signal limited to 8 dB peak to average power ratio. The PWM/PPM drive signal is generated using the improved Cartesian sigma delta techniques. It is shown that an RF oversampling by a factor of four meets the WLAN spectral mask, and WCDMA specification is met by an RF oversampling of sixteen.

RF Power Silicon-On-Glass VDMOSFETs

Applicability of vertical double-diffused MOSFETs for future base station power amplifiers has been demonstrated by characterizing the first devices fabricated in a substrate transfer silicon-on-glass technology. For a gate length of 0.8 /spl mu/m and gate width of 350 /spl mu/m, the measured f/sub T//f/sub max/ is 6/10 GHz, and the breakdown voltage approaches 100 V. The devices feature an output power of 12 dBm at the 1-dB compression point, excellent linearity (IM3/IM5 of -50/ -70 dBc at 10-dB backoff) and high power gain (14 dB) at 2 GHz, and are the first vertical DMOSFETs suitable for 2-GHz power applications. Excellent heat sinking and no significant degradation of the quiescent current due to hot-carrier injection ensure thermal stability and good long-term reliability of the fabricated devices.