International Mobile Telecommunications Research Articles

The evaluation of EMI characteristics of 4G-IMT system on FAST around its RQZ

Mobile communication base stations have become ubiquitous with the popularization and development of mobile communication services. Although the Chinese government has designated a radio quiet zone (RQZ) specifically for Five-hundred-meter Aperture Spherical radio Telescope (FAST), the 4G International Mobile Telecommunications (4G-IMT) system is still heavily used to meet the communication needs around the RQZ. To assess the Electromagnetic Interference (EMI) caused by 4G-IMT base stations on the performance of FAST, this paper employs the International Telecommunication Union (ITU) deterministic radio wave propagation prediction model. The interference of 4G-IMT base stations on FAST is evaluated based on relevant parameters, such as the frequency used by both FAST and the base station, in conjunction with the FAST threshold protection requirements. The results indicate that 47.73 % of the data exceed the radio astronomy protection threshold of FAST. In addition, a field experiment was conducted to verify the accuracy of the radio wave propagation prediction method used. The root-mean-square error between the predicted value and the measured value was found to be 6.94 dB, supporting the accuracy of the predicted results. The findings of this study can help suppress interference from mobile communication services around the RQZ of FAST and optimize the electromagnetic environment around FAST.

Co-Channel Compatibility Analysis of IMT Networks and Digital Terrestrial Television Broadcasting in the Frequency Range 470-694 MHz Based on Monte Carlo Simulation.

According to Resolution 235 adopted during the World Radiocommunication Conference 2015 (WRC-15) and the preliminary agenda item 1.5 of WRC-2023, the International Telecommunication Union Radiocommunication Sector (ITU-R) has been entrusted to carry out sharing and compatibility studies between broadcasting and mobile services in the frequency range 470-694 MHz in Region 1. This study specifically focuses on evaluating electromagnetic compatibility in potential co-channel sharing scenarios between Digital Terrestrial Television Broadcasting (DTTB) and International Mobile Telecommunications (IMT) systems within the 470-694 MHz frequency band that may arise in the foreseeable future. To assess the conditions for coexistence, a Monte Carlo simulation method implemented through the SEAMCAT software version 5.4.2 is employed, examining six potential interference scenarios. The simulation results yield the minimum coordination distance required between IMT and DTTB services in the 470-694 MHz band based on the protection criteria to ensure harmonious coexistence while maintaining satisfactory performance. Furthermore, the study investigates the impact of various factors such as transmitter power, antenna heights, coverage radius, antenna discrimination, and antenna tilt angle on the separation distances. The focus lies primarily on critical interference scenarios across neighboring countries' borders. The simulation outcomes confirm that sharing the same frequency band between IMT and DTTB networks would result in significant mutual interference. Nevertheless, carefully analyzing diverse parameters and assumptions helped provide recommendations to reduce the required separation distances. These findings are valuable for broadcasters, mobile operators, and regulators in establishing the technical coexistence conditions for DTTB and IMT in the new band.

The Analysis and Verification of IMT-2000 Base Station Interference Characteristics in the FAST Radio Quiet Zone

In this study, we aim to analyze the electromagnetic interference (EMI) regarding the Five-hundred-meter Aperture Spherical radio Telescope (FAST) caused by base stations in the International Mobile Telecommunications-2000 (IMT-2000) frequency band. By analyzing the frequency bands used by the transmitting and receiving devices and the surrounding environmental parameters and utilizing an approach to predicting radio wave propagation loss that is based on deterministic methods, we conclude by comparing the predicted received power at the FAST with its interference protection threshold. Our analysis demonstrates that, currently, only 55.31% of IMT-2000 base stations in the FAST radio quiet zone (RQZ) meet the protection threshold. Additionally, this article verifies the applicability and accuracy of the radio wave propagation model used in the research based on field strength measurements. Overall, this study provides valuable insights for improving the electromagnetic environment surrounding FAST and reducing the EMI caused by mobile communication base stations. It also provides corresponding analysis methods and useful suggestions for analyzing electromagnetic radiation interference in other radio telescopes.

Coexistence Analysis Between IMT-2020 and AES operating in L Band on a Final Approach

This paper is regarding the statistical coexistence analysis between a cluster of International Mobile Telecommunication 2020 (IMT-2020) Base Stations and an Aircraft Earth Station (AES) operating during flight time in the L Band on a final approach. We assess the cumulative distribution function (CDF) of interference-over-noise ratio (INR) considering the fuselage attenuation contribution and compare it with the AES protection criteria. Our coexistence analysis approach considers the use of a high gain AES commercial antenna model, for an aircraft at two different altitudes, 187 m and 83 m, for 3600 m and 1600 m of horizontal distance from the runway threshold, respectively. Therefore, considering the IMT-2020 suburban scenario near the airport, simulation results presented an INR that met the protection criteria for 100% and 99.95% of the time for the distances of 3600 m and 1600 m from the runway, respectively, making the spectrum sharing feasible between systems. To the best of our knowledge, this is the first time in the literature that fuselage attenuation considering part of the plane, in the L-band is presented in a statistical coexistence analysis.

Flexible terahertz metamaterial filter with high transmission intensity and large tuning range for optical communication application

The resonant frequency of indoor wireless communication based on wireless fidelity (Wi-Fi) and Bluetooth is limited to several gigahertz (GHz). Following the international mobile telecommunications specification proposed by international telecommunication union in 2020 (ITUIMT-2020), communication links with sub-terahertz (sub-THz) waves are desired for indoor networks in the coming years. In this study, we present a flexible terahertz (THz) metamaterial (FTM) filter consisting of cross-shaped metamaterial configurations on a polydimethylsiloxanes (PDMS) substrate. As a band-stop filter, such designed FTM filters possess the selectivity of resonant frequency and thus provide a controllable transmission carrier for a broad frequency range in the sub-THz window. The FTM filters can generate a tuning range of over 85-GHz resonant shift from 360.6 GHz to 446.1 GHz by changing the distance between the top and bottom metamaterial layers. For specific frequency carriers in passband, the proposed FTM filters show the transmission intensity higher than 94%. This design will play a key role in the future indoor wireless communication with miniaturization, large tuning range, and high transmission intensity characteristics. • Tunable metamaterial filter (TMF) shows high transmission intensity and large tuning range. • Tuning range of TMF is 85 GHz from 360 GHz to 445 GHz. • For wireless THz communication from, the proposed TMF can modulate specific carriers. • TMF enables the transmission end of the communication system more flexible in data processing. • TMF provides a feasible scheme for the future ultra-high-speed wireless transmission system.

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.

An intelligent energy efficient handover mechanism with adaptive discontinuous reception in next generation telecommunication networks

Long Term Evolution (LTE) and LTE-Advanced (A) networks have been introduced to accommodate the User Equipment (UEs) that supports high complex technologies such as OFDM, SC-FDMA, MIMO. Recently, 3GPP presented 5G technology to meet the performance requirement of the International Mobile Telecommunication (IMT)-2020. It supports three specific services like Enhanced Mobile Broadband (eMBB), Ultra-Reliable Low Latency Communication (URLLC), massive Machine Type Communication (mMTC). To increase the capacity of the network, 5G will deploy an ultra-dense network in the metro area. It fulfils the spectral efficiency requirement but at the same time increases handover rate. Due to handover, the power consumption of UEs may increase dramatically. To overcome this issue, LTE-A network adopts Discontinuous Reception (DRX) to conserve battery life of UE. 5G networks will also apply evolved variations of this scheme. In general, DRX is composed of some parameters and these need to be optimized during mobility. This paper presents a method for preservation of the battery life of UEs during mobility. The proposed mechanism comprises of three parts. In the first part, Part 1, the operation of normal DRX during mobility is explored. The next parts, Part 2 and Part 3, utilize the machine learning-based methods for the pre-prediction of Target eNB (TeNB) and provide ranks to the UEs during handover. Further, DRX parameters are adjusted according to the dynamic behaviour of the network. Handover latency, end-to-end delay is improved by 20% and 55%, respectively as compared to the conventional scheme. Further, machine learning based (Part 2) and dynamic adjustment of DRX parameters (Part 3) contribute to enhance the power saving factor by maximum up to 85%, and 33% as compared to state of art mechanism.

Uplink coverage enhancements for extremely large-cell sites

In urban areas, the network operators deploy small-cell sites and install a large number of base stations to support densely populated cellular users. A similar small-cell deployment in rural areas is not feasible for the operators, as it will significantly increase the capital expenditure, and the return on the investment will also be comparatively lower. Hence, the most feasible way to provide cellular connectivity to rural areas is the deployment of large-cell sites. However, the technology developed for International Mobile Telecommunications (IMT)-Advanced standard (or 4G) was evaluated for an inter-site distance of 1.732 km, making the large-cell connectivity required for rural areas an afterthought. For cellular last-mile rural connectivity to be a reality through IMT-2020 (or 5G), the key is to have future technologies supporting large cells. In large-cell sites, the users experience comparatively more path loss, and thus, have poor signal coverage. Further, compared to downlink, the transmission power in uplink is limited, and therefore, uplink transmissions define the coverage of the communication system. Motivated by this, we propose several coverage solutions for uplink, considering an extremely large-cell site scenario. We initially analyze the received signal-to-noise ratio with 4G/5G systems at various distances based on the link budget evaluation. At larger inter-site distances, we show that it is infeasible to achieve cellular coverage with the current 4G/5G specifications. We then propose enhancements related to the waveform, modulation and coding schemes, resource allocation, and power control mechanisms. We evaluate the proposed enhancements through system- and link-level simulations, and show a significant improvement in the coverage for cell-edge users. We also show that our proposed enhancements achieve close to two times the improvement in the network capacity when compared to the currently available 5G specifications.

The ITU IMT-2020 Standardization: Lessons from 5G and Future Perspectives for 6G

ABSTRACT The evaluation of candidate International Mobile Telecommunications-2020 (IMT-2020) radio interfaces ended in February 2021, with three technologies being approved while another two were granted additional time to demonstrate their suitability. This marks a useful milestone at which the International Mobile Telecommunications (IMT) standardization process can be evaluated, and its implications for 6G explored. We argue that the relationship between IMT standardization and identification is increasingly problematic, with identification requiring the refarming of spectrum already allocated to other services. Furthermore, as standardization is largely done outside of the International Telecommunication Union (ITU), being part of IMT is largely a way to obtain more spectrum. While these developments question the value of the existing approach, we argue that changes are necessary to the IMT standardization processes given the value to be gained from a single global mobile standard.

Development of a Spectrum Auction Policy for International Mobile Telecommunications in South Korea Under Agent-Based Simulation

Development of a Spectrum Auction Policy for International Mobile Telecommunications in South Korea Under Agent-Based Simulation

Resource Allocation Algorithm Based on Power Control and Dynamic Transmission Protocol Configuration for HAPS-IMT Integrated System

The high altitude platform station (HAPS) system is an essential component of the air-based network. It can shorten transmission delay and make a better user experience compared with satellite networks, and it can also be easily deployed and cover a larger area compared with international mobile telecommunications (IMT). In order to meet the needs of users with asymmetric and random data flow, the spectrum sharing and dynamic time division duplexing (TDD) mode are used in HAPS-IMT heterogeneous network. However, the cross-link interference brought by TDD mode will lead to the degradation of system performance. In this paper, a resource allocation algorithm based on power control and dynamic transmission protocol configuration is proposed. Firstly, a specific timeslot, “low power almost-bank subframe (LP-ABS)”, is introduced into the frame structure of the HAPS physical layer. The transmission protocol designing could mitigate inter-layer interference efficiently by power control in “LP-ABS”. Secondly, the utilization function is adopted for assessing the system performance, which gives attention to both diversified requirements on the quality of services (QoS) and the throughput of the HAPS-IMT system. Simulation results show that power control and resource allocation technologies proposed in this paper can effectively improve system performance and user satisfaction.

High-Altitude Platform Stations as IMT Base Stations: Connectivity from the Stratosphere

High-altitude platform station (HAPS) as International Mobile Telecommunications (IMT) base station (HIBS) has been attracting the attention of aerospace and telecommunication companies from many countries in recent years. The HIBS' remarkable differential feature is the possibility of using HAPS to complement the IMT terrestrial coverage, benefiting from the platforms being located in the stratosphere, enabling much wider coverage when compared to conventional terrestrial solutions. In addition, the COVID-19 pandemic has highlighted the technological and social differences among countries, mainly due to the poor quality, or even absence, of Internet connectivity. HIBSs might efficiently support reducing the digital divide, since they provide connectivity to the same mobile devices as the terrestrial networks, which allows this non-terrestrial connectivity solution to increase global coverage and expand mobile connectivity for everyone. This article describes the fundamentals of the HIBS, as well as its deployment scenarios and regulatory aspects. Furthermore, it is reported, for the first time in the literature, a coexistence analysis between HIBS and fixed services point-to-point (FS-PP), as an International Telecommunication Union - Radio-communication Sector preparatory study for the support of decisions to be made at the 2023 World Radiocommunication Conference. The simulations demonstrate the feasibility of coexistence between HIBS and FS-PP active links, sharing the HIBS Band 2 around 2 GHz.

6G: The Next Horizon: From Connected People and Things to Connected Intelligence

This book presents an in-depth technical understanding of 6G wireless networks. It not only discusses cutting-edge wireless services and technologies, but also sheds light on the network requirements, capabilities, and applications. Following in the footsteps of 5G, the goal of 6G mobile networks is to usher in an era of ubiquitous intelligence. 6G will act as a liaison between the physical world and the networked world. This objective is ambitious and will have a significant impact on our culture and economy. Part I of this book provides a brief history of mobile communications, tracing its development from 2G to 6G networks as well as addressing six key technological trends for the future of linked intelligence. Part II investigates potential 6G use cases with the specific performance criteria, such as lower latency, greater reliability, and larger capacity. The authors categorize typical use cases into six groups, each with its own chapter. Part III studies the breadth and limits of 6G design, looks into a range of supporting technologies that have the ability to meet key performance indicators (KPIs), and then covers the theoretical basics of 6G radio and network technologies. Part IV examines the future International Mobile Telecommunications (IMT) spectrum from the standpoint of communications and sensing, as well as the associated channel modeling methods and some sample channel measurements. Part V presents the design principles and potential enabling technologies for 6G air interfaces. In particular, it highlights the paradigm shifts of air interface building in comparison to 5G and previous generations with detailed discussions on a variety of enabling technologies. Part VI investigates the design concepts and enabler technologies for 6G network architectures. In particular, it starts with a discussion of paradigm changes in network architecture design, followed by a number of the novel technologies featured in 6G networks. Part VII (Chapter 33) ends the book by summarizing the present worldwide state of the 6G ecosystem, including research initiatives, platforms, workshops and publications on 6G, and then forecasting a possible path until 2030. In conclusion, this book presents an overview of 6G from the perspective of intelligence-of-everything, which includes drivers, essential capabilities, use cases, key performance indicators, and technological breakthroughs. The authors emphasize recent advances such as immersive human-centric communications, sensing, location, imaging, linked machine learning and networked artificial intelligence, Industry 4.0 and beyond, etc. This book can serve as a good reference for practitioners and researchers in the field, in a bid to get an idea of the current and future research focus in this emerging area.

Compatibility between EESS (passive) in band 23.6–24 GHz and 5G in band 24.25–27.5 GHz

The 24.25–27.5 GHz band was allocated to IMT (International Mobile Telecommunication) during the World Radiocommunication Conference (WRC) after studies were elaborated between this potential allocation and the services in adjacent band and in particular with Earth Exploration by satellite in adjacent band. Several studies were evaluated during the WRC-19 cycle. This document describes only the studies undertaken by some European states for the protection of Earth exploration by satellite. The elements provided in this document are the basis of the European position for WRC-19 on the protection of passive EESS in 23.6–24 GHz.

Editorial for Wiley's IJSCN Special Issue “Satellite networks integration with 5G”

Editorial for Wiley's IJSCN Special Issue “Satellite networks integration with 5G”

Design of Compact Wideband Circularly Polarized Hexagon-Shaped Antenna Using Characteristics Mode Analysis

The design of an antenna, for its subsequent characterization by means of real sets of measurement, requires a specific modeling that allows a best approximation to the actual construction of the device and true measured values. Like Fourier series expansion, the characteristic mode analysis (CMA) creates a set of orthogonal true current on a conducting material with arbitrary geometry. In this work, a hexagon-shaped wideband circularly polarized (CP) antenna using CMA is presented. The design of the proposed antenna is completed in two stages: first, a hexagon-shaped monopole is designed to achieve circular polarization in the upper frequency band, and subsequently a hexagon-shaped slotted patch is implemented for obtaining circular polarization in the lower frequency band. This procedure helps in achieving the wideband CP antenna. In place of using the conventional method of analyzing simulated surface current distribution to verify CP radiation, CMA is used to understand the different modes of the antenna and their contribution toward CP radiation of antenna. A prototype of the proposed antenna is fabricated with dimensions 0.36λ×0.36λ×0.013λ ( λ corresponds to the wavelength for lowest working frequency) to validate the simulated results. The impedance bandwidth of the proposed antenna is 2.3-7.6 GHz and the 3-dB axial ratio bandwidth (ARBW) of the antenna is 3.4-6.5 GHz. The measured peak gain of the antenna is 4.6 dBic. The proposed antenna exhibits a consistent radiation pattern, and the operating frequency band of the antenna effectively includes the international mobile telecommunication (IMT), industrial, scientific, and medical band (ISM), and WiMAX spectrums.

5G New Radio Key Performance Indicators Evaluation for IMT-2020 Radio Interface Technology

The International Telecommunication Union (ITU) has recently announced the detailed 5G specifications for International Mobile Telecommunications (IMT-2020). A number of candidate Radio Interface Technologies (RITs) were being evaluated by the independent evaluation groups of the ITU. Meanwhile, the roll out of fifth generation (5G) is now going on, and 5G services are offered by more than 160 mobile network operators (MNO). This paper presents the evaluation of the proponent technologies, including the ones specified as <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3^{\text {rd}}$ </tex-math></inline-formula> generation partnership project (3GPP) 5G new radio (NR). The entire 3GPP specifications were examined and evaluated through simulation using Matlab and a custom simulator based on the Go-language. The simulator facilitated the comprehensive evaluation of the 5G NR performance by using the IMT-2020 evaluation framework. Some of the submitted technologies displayed certain discrepancies which were reported to ITU as well as discussed with proponents to improvise the shortcomings. The detailed results and observations are presented in this paper.

Adjacent channel compatibility between IMT and ubiquitous FSS Earth Stations in the 3.4–3.8 GHz frequency band

This study has investigated the mitigations necessary for successful compatibility between International Mobile Telecommunications (IMT) services and Fixed Satellite Service (FSS) Earth Stations operating in adjacent frequency bands. We consider a problem where IMT services operate in the 3.4–3.6 GHz frequency band and FSS Earth Stations operate in the adjacent 3.6–3.8 GHz band (both bands are within the frequency range designated C-band). The results presented in this paper are applicable to other boundaries between IMT and FSS operating in C-band. This is an adjacent band compatibility problem, hence the mitigation considered is based on frequency separation. We firstly perform a co-frequency interference analysis and then determine the Net Filter Discrimination available for a range of possible frequency separations including Guard Bands. These calculations rest on some assumptions regarding the IMT transmitter and FSS receiver spectrum masks. We present some results which show that an 18 MHz Guard Band is sufficient to mitigate interference. This analysis is based on the median aggregate interference-to-noise ratio $$\Sigma I/N$$ delivered by our co-frequency analysis, using a − 10 dB threshold and covering all of the spectrum mask combinations considered in the study.

Licensed shared access field trial and a testbed for satellite‐terrestrial communication including research directions for 5G and beyond

SummaryThis paper describes a licensed shared access (LSA) testbed and field trials using a live network. The testbed includes real 4G base stations and up to 1000 virtual base stations, in the spectrum sharing scenario between satellite and cellular systems. The trials focus on 5G pioneer bands 3.4–3.8 GHz and 24.25–27.5 GHz where a satellite system is operating in the downlink direction and a cellular system is accessing the same band. The designed testbed supports both frequency bands. The performance evaluation concerns evacuation and frequency change times using different types of base stations in 3.6 GHz, that is, how fast the system relinquishes the shared band to the primary user and continues transmission using another band. We show that our LSA system is scalable and able to support large number of base stations. In addition, we investigate how satellite systems could reuse International Mobile Telecommunication (IMT) bands to offer enhanced satellite communication services for land, maritime, and aeronautical applications. Preliminary simulations and analysis confirm the possibility to reuse IMT spectrum for satellite systems without causing harmful interference to the terrestrial system.

Estimation of Electromagnetic Compatibility Between DVB-T/DVB-T2 and 4G/5G in the 700 MHz Band for Co-Channel Case

Abstract The 694–790 MHz band (700 MHz) known also as the second digital dividend was allocated to the mobile radiocommunication service on a primary basis in Region 1 and identified to International Mobile Telecommunications by the World Radiocommunication Conference 2012 (WRC-12). The designation of mobile service in Europe and other countries of Region 1 in 700 MHz band was obtained after the World Radiocommunication Conference 2015 (WRC-15). Administrations of Region 1 will be able to plan and use these frequencies for mobile networks, including IMT. The goal of this study is to estimate the electromagnetic compatibility of Digital Video Broadcasting – Terrestrial (DVB-T/DVB-T2) and LTE (Long Term Evolution) technology operating both in 700 MHz band. The study assumes frequency division duplex (FDD) channel arrangement of 703–733 MHz (for uplink) and of 758–788 MHz (for downlink). The model contains two parts: a DVB-T/DVB-T2 system and LTE mobile broadband network. Co-channel scenario is considered in this paper, and possible impact of DVB-T/DVB-T2 on LTE base stations (receivers) is also investigated. The Monte Carlo simulations within SEAMCAT software and the Minimum Coupling Loss (MCL) method are used for interference investigation. The coordination trigger field strength value predetermined by GE06 Agreement is also used in this study. The Monte Carlo method presents more relaxed electromagnetic compatibility scenario in comparison with the MCL method. For SEAMCAT simulations, ITU-R P.1546-5 radio propagation model is used. The obtained results present the required minimum separation distance between DVB-T/DVB-T2 and LTE networks in the 694–790 MHz in order to provide the necessary performance of LTE mobile network.