International Mobile Telecommunications Research Articles

Sharing and compatibility studies of IMT systems with Earth Exploration-Satellite Service in 26 GHz frequency band

In this paper, the coexistence interference of 26 GHz-band International Mobile Telecommunications (IMT) and Earth Exploration-Satellite Service is analyzed based on actual satellite orbit and ITU-R system characteristic. Specifically, the aggregate interferences of IMT system base stations (BS) and users (UE) to Earth Exploration-Satellite Service earth station are studied, considering high frequency band radio propagation clutter loss. The results show that the IMT base station and user deployment can coexist with the Earth Exploration-Satellite Service in the band. The provided results are useful for design of future 26 GHz IMT-2020 (5G) wireless communications systems and Earth Exploration-Satellite Service.

Bandwidth-Enhanced Broadband Dual-Polarized Antennas for 2G/3G/4G and IMT Services

Two bandwidth-enhanced broadband dual-polarized antennas (BEBDPAs) are proposed for 2G/3G/4G wireless communication systems and international mobile telecommunication services. The first BEBDPA is composed of two perpendicularly crossed dipoles. Its bandwidth is enhanced by introducing a parasitic loop below the two crossed dipoles and a parasitic disk with four parasitic strips above. The BEBDPA achieves an impedance bandwidth of 64% for reflection coefficients <–15 dB (1.4–2.75 GHz) with an isolation of 30 dB. The second BEBDPA is based on a pair of crossed dual-dipole elements with a parasitic disk above for bandwidth enhancement, featuring a reduced antenna size. The impedance bandwidth of the second BEBDPA is about 63% (1.4–2.7 GHz) with an isolation of 30 dB.

Compatibility Studies of IMT System and Automotive Radar in the Frequency Range 71-78 GHz

The millimeter waves have large available bandwidth and thus gigabit throughput can be easily achieved for future wireless communication systems. The frequency band has been identified as potentially suitable frequency band for IMT (International Mobile Telecommunications) systems. In this paper, consideration ECC and Huawei relevant paper, the coexistence interference of 71-78 GHz-band international mobile telecommunications (IMT) and automotive radar is analyzed based on actual geographical and ITU-R system characteristic. Specifically, the interferences of IMT system base stations (BS) and users (UE) to automotive radar are studied, considering high frequency band radio propagation clutter loss. This paper presents the Monte Carlo results in terms of the level of compatibility interference power vs. the distances between IMT and automotive radar in the straight trajectory by using Visualyse V7.9 simulation tool. The results show that in some case the IMT BS operating in the band 71-76 GHz may be well compatible with the automotive radar, the interference power value is mainly under protection criterion value. The provided results are useful for design of future 71/80 GHz IMT-2020 (5G) wireless communications systems and automotive radar system.

Coexistence Without Interference: Interference Mitigation on DVB-T Reception Caused by Neutral Systems Operating in the Digital Dividend Band

The migration from analog to digital television (TV) broadcasting has introduced significant improvements in terms of spectral efficiency. As a result, the number of radio channels required to ensure equivalent coverage has been dramatically reduced [1]. This efficiency gain has allowed the release of a valuable portion of spectrum (previously assigned to analog TV broadcasting) in the 790-862-MHz subband (channels 61-69), often called the digital dividend. This 72-MHz slice of the spectrum is now assigned exclusively to international mobile telecommunications (IMT) [2], [3]. Vis &#x000E1; vis the mobile communications markets, the current data dynamics demand more wireless access to cope with the growing user consumption of mobile services.

A Compact Broadband Dual-Polarized Antenna Array for Base Stations

A compact ±45° dual-polarized broadband antenna array is proposed in this letter for base stations. For the sake of structural simplicity, low profile, and ease of mass production, printed dipoles are adopted as the dual-polarized antenna element. To achieve the broadband performance, radiators are designed to be spline-edged bowties, and they are fed by tapered transmission lines. Moreover, to improve the symmetry and stability of the radiation pattern, the Pawsey stub baluns are used to balance the antenna structure. Finally, an eight-element antenna array prototype backed by a folded reflector is fabricated and measured. The compact antenna array has a broad bandwidth of 68% (1.427-2.9 GHz) with a voltage standing-wave ratio less than 1.5 and stable radiation properties to provide international mobile telecommunication services over 2G/3G/LTE systems and Land S-bands released recently.

Mobile communications – On standards, classifications and generations

The research question addressed in this paper is concerned with the manners in which the general technological progress in mobile communications is characterized and the reasons for the differences in these modes of manifestation. The relevance of this research question is that the different manifestation modes create a degree of confusion in communications and discussions on mobile technologies. At the same time, it should be recognized that different manners of categorizing technologies illustrate the fact that categorizations are based on different purposes of the classification exercises. Also, the paper discusses the role of the International Telecommunication Union (ITU) in the processes of mobile standardization.In common parlance, progress in mobile technologies is mostly referred to as generations. In ITU, the classification terminology is that of International Mobile Telecommunication (IMT) standards. In the specialized standards body with a central position in the standardization of core mobile technologies, namely 3GPP (3rd Generation Partnership Project), the terminology of ‘releases’ is used. In order to address the research question, the paper uses an analytical framework based on the differences and relationships between the concepts of standards, classifications and generations.

Optimum Ultra-Reliable and Low Latency Communications in 5G New Radio

To satisfactorily gratify the scope of International Mobile Telecommunications 2020 (IMT-2020), 3GPP has launched the standardization activity of the fifth generation (5G) New Radio (NR) to deploy the first phase system (Release 15) in 2018 and the ready system (Release 16) in 2020. Different from the IMT-Advanced system solely enhancing the transmission data rates regardless the variety of emerging wireless traffic, the IMT-2020 system supports diverse wireless services including enhanced mobile broadband (eMBB), massive machine-type communications (mMTC) and ultra-reliable and low latency communications (URLCC) to fully capture wireless applications in 2020. Among all the wireless services, URLLC jointly demanding low latency and high reliability and mMTC emphasizing on high reliability create substantial impacts to the designs of NR air interface. On the advert of the conventional feedback based transmission in LTE/LTE-A designed for eMBB imposing potential inefficiency in supporting URLLC, in this paper, we revisit the feedbackless transmission framework, and reveal a tradeoff between these two transmission frameworks to latency and reliability guarantees. A multi-armed bandit (MAB) based reinforcement learning approach is therefore proposed to achieve the optimum harmonization of feedback and feedbackless transmissions. Our simulation results fully demonstrate the practicability of the proposed approach in supporting URLLC, to justify the potential of our approach in the practice of 5G NR.

Software implementation of LTE-advanced using Matlab Simulink

Long Term Evolution Advanced (LTE-A) is the evolution of the LTE that developed by 3rd Generation Partnership Project (3GPP).LTE-A exceeded International Telecommunication Union (ITU) requirements for 4th Generation (4G) known as International Mobile Telecommunications (IMT-Advanced). It is formally introduced in October 2009. This paper presents a study and an implementation of the LTE-A downlink physical layer based on 3GPP release 10 standards using Matlab simulink. In addition, it provides the LTE-A performance in terms of Bit Error Rate (BER) against Signal to Noise Ratio (SNR) for different modulation and channel coding schemes. Moreover, different scenarios of Carrier Aggregation (CA) are modeled and implemented. The Simulink model developed for the LTE-A transceiver can be translated into digital signal processor DSP code or VHDL on FPGA code.

Stratospheric Winds and Rain Effect on HAPS Backhaul Link Performance

&#x0D; today, fourth generation of mobile communication turn out to be in active mode for several countries and one of the most promisingtechnologies used for a backhaul service is High Altitude Platform Stations (HAPS). While HAPS still suffers from environment effects in stratospheric layer like rain and winds.In this research paper, a study of the effect of the positional instability of HAPS (aircraft category) on the link level performance of an International Mobile Telecommunications Advanced (IMT-Advanced) served by HAPS is presented. The analysis is performed in three different climatic conditions of Malaysia, which is a tropical country. Then two types of radio links have been analyzed – firstly, the end user link which connects aerial station and end user and then, backhaul link that establishes communication between HAPS and Ground Transmission Gateway (GTG). A Problem of fluctuations in the signal level and degrading the performance level had been solved by analyze the behavior of winds in stratospheric layer. Finally, the effect of instability was given in received signal level variation and link availability or percentage outage of the link. Obtained results showed that the link availability of the backhaul link meets the ITU-R recommendations. Lately, it can be said that the results of the service obtained can be used to design the communication network with a higher level of user satisfaction.&#x0D;

Coexistence conditions of LTE-advanced at 3400–3600 MHz with TVRO at 3625–4200 MHz in Brazil

In Brazil, the 3625–4200 MHz frequency band (C-band) is widely used by TV receive-only (TVRO) application in the fixed satellite service (FSS). The 3400–3600 MHz adjacent band can be used by International Mobile Telecommunications (IMT) systems, but many low noise block downconverters (LNB) of TVRO sold in Brazil have not a C-band filter. Thus, it is likely that the low cost LNB used in TVRO receivers would be overloaded by the IMT-systems emissions within the LNB wideband receiver, even the IMT stations operating accordingly to international standards. This paper shows that both systems can coexist harmoniously depending on the characteristics of the IMT system and on the FSS receiver specifications.

A comparative study on the design and simulation of TFBAR and polyimide-TFBAR based RF bandpass filters

The present work focusses on the design and simulation of a thin film bulk acoustic resonator (TFBAR) and a polyimide based TFBAR (PI-TFBAR) and compares the radio frequency (RF) bandpass filter response designed from these resonators. The Polyimide layer in the PI-TFBAR acts as an acoustic wave reflector along with providing mechanical strength to the device. The designed third order bandpass filter has a ladder topology. The insertion loss of the TFBAR filter is 1.69 dB and the return loss is 39.60 dB whereas the insertion loss and return loss are 1.71 and 23.7 dB respectively for the PI-TFBAR filter. The bandwidth of the TFBAR filter is 68.0 MHz and for PI-TFBAR it is 25 MHz. The proposed filter designs, with further optimization, may have application in the 2.6 GHz band, which has been identified by the International Telecommunication Union as a global band for International Mobile Telecommunications and is one of the core bands of LTE-Advanced technology.

Dual-Band Half-Elliptic Hoof Antenna With Mathieu Function for a Femto-Cell Network

The design of a half-elliptic hoof antenna for a femto-cell network in a multi-input multioutput system is proposed. The proposed half-elliptic hoof antenna incorporates half-elliptic surfaces, and has multiresonance frequencies in its TM modes. The half-elliptic design of the proposed antenna resonates with two main current paths, and the resonant frequency of each mode can be calculated using the Mathieu function. Moreover, an additional resonator is inserted between the half-elliptic patch and a ground to obtain additional resonance frequency and a wider bandwidth on the high band. The proposed antenna covers the frequency bands from 880 to 960 MHz and from 1710 to 2170 MHz for Global System for Mobile Communications (GSM)/Digital Cellular System (DCS)/Personal Communications Service (PCS)/International Mobile Telecommunications (IMT) with a peak gain of 6.8 dBi. To validate the design of the proposed antenna, the analysis of the antenna using the simulated and measured results is presented and discussed.

A microstrip wideband monopole antenna for multisystem integration by utilizing stepped-impedance structure and L-shaped slot

In this article, a coplanar-waveguide (CPW)-fed dual-band antenna for applications of the multisystem integration has been demonstrated. The resonance analysis of the stepped-impedance (SI) monopole is presented by using the transmission-line analysis method. The frequency-response characteristics of the SI-monopole, such as the resonance condition and harmonic response, are systematically summarized. Furthermore, utilizing several simple techniques, such as bent feeding topology, asymmetric ground plane, and an L-shaped slot etched in the ground plane, a right-hand circularly polarized (RHCP) radiating wave at 1.57 GHz and a left-hand circularly polarized (LHCP) radiating wave at 2.33 GHz are excited for the applications of the global positioning system (GPS) and the satellite digital audio radio (SDAR) service system. After optimization of the geometrical parameters of the proposed antenna, the measured impedance bandwidths of a reflection coefficient less than −10 dB range from 1.40 to 2.98 GHz and from 4.48 to 6.27 GHz, and thus covers most of the commercial wireless communication systems, such as GPS, digital cellular system (DCS), personal communication system (PCS), international mobile telecommunications (IMT)−2000, wireless local area networks (WLAN), and long-term evolution (LTE) 2300/2600. The measured 3-dB axial ratio (AR) bandwidths are about 80 MHz at 1.57 GHz and 100 MHz at 2.33 GHz.

Spectrum Considerations for 5G Mobile Communication Systems

Increased demand of consumers on services in the mobile environment with high data rate and technologically developed mobile broadband communication systems will require more spectrum to be available in the future. The new technologies require frequencies for their development and usage. One of the main objectives of fifth generation (5G) mobile communication systems, known also as IMT-2020, is to increase the current data rates up to several gigabits per second (Gbit/s) with even more than 10 Gbit/s. One possibility is to consider the use of higher frequencies in order to increase the available bandwidth, which is necessary to achieve such data rates. Main idea of the research is to investigate the available International Mobile Telecommunications (IMT) frequency bands and possible new one – above 6GHz for possible identification worldwide and in Europe for IMT by the 2019 World Radiocommunication Conference (WRC-19). Main characteristics and requirements of IMT-2020 are also provided in this paper.

Preliminary Coexistence Studies between IMT-2020 systems and inter-satellite service in 26 GHz

This paper focuses on the sharing and compatibility studies of International Mobile Telecommunications 2020 (IMT-2020) and inter-satellite service (ISS) in 26 GHz frequency band, which was selected by International Telecommunications Union (ITU) as one of the most promising candidate frequency bands for 5G. Based on relevant ITU recommendations and reports, and current technical characteristics of both systems, a methodology is developed for the interference coexistence analysis between them. The spatial and temporal distribution analysis is proposed and the calculation of IMT-2020 aggregate interference takes the actual urban population into consideration. The results show that these two systems have considerable possibilities in coexistence in 26 GHz frequency band.

Evaluation of LTE and Aeronautical Radionavigation Service Electromagnetic Compatibility in 694–790 MHz Frequency Band

In 2012 the 694-790 MHz (700 MHz) band was allocated to the International Telecommunication Union (ITU) Region 1 for mobile service (excluding aeronautical mobile), and was identified to the International Mobile Telecommunications (IMT). However, countries of Region 1 listed in Radio Regulations footnote No. 5.312 will also be able to continue using of these frequencies for their aeronautical radionavigation service (ARNS). This allocation comes into force immediately after the 2015 World Radiocommunication Conference (WRC-15). The objective of this article is to assess the electromagnetic compatibility of aeronautical radionavigation service and mobile service operating in 694 MHz–790 MHz. For interference analysis the Minimum Coupling Loss (MCL) method and Monte Carlo method simulation was used. The obtained results provide the minimum coupling distance required between ARNS and mobile service Long Term Evolution (LTE) stations to maintain the required performance level of the ARNS systems.DOI: http://dx.doi.org/10.5755/j01.eie.22.6.17231

Dual-Band Patch Antenna Based on Resonant-Type Composite Right/Left-Handed Transmission Lines for IMT2000 and WLAN Applications

This paper proposed a dual-band resonant-type composite right/left-handed transmission lines which consisting of complementary single multi-split-ring resonators and a series capacitive gaps. For characteristics, the equivalent circuit mode for the design of antenna is discussed. And the effect of different combining complementary split-ring resonators to zeroth-order frequency is also analyzed. Then, a dual-band patch antenna for International Mobile Telecommunication (IMT2000) and wireless area networks applications is proposed. The result of simulated and measured for antenna are used to verify the theoretical prediction. Simulation and measure results shown that the proposed antenna operates at 1.97 and 2.45 GHz for voltage standing wave ratio <2. Also these results shown the antenna has a stable radiation patterns and good gain. All the results for antenna obtained in this work have been simulated with CST Microwave Studio.

Spectrum Sharing for LTE-A and DTT: Field Trials of an Indoor LTE-A Femtocell in DVB-T2 Service Area

In the near future, many applications such as environmental sensors, smart objects, health sensors, and personal devices will be connected to mobile networks requiring additional spectrum. Studies have been made to demonstrate a low occupancy time and locations on the digital terrestrial television (DTT) band. This available or unused spectrum have been called “TV-White-Spaces.” In the 2015 World Radiocommunication Conference, the ITU decided to re-allocate the 700 MHz band (694–790 MHz) for International Mobile Telecommunications (IMT) services and also emplaced the discussion of the future use of the DTT band (470–694 MHz) to 2025, for which studies have been requested. In this paper, we study a particular case which goes a step beyond the previous ones, as it aims at sharing the same frequency band in the same area between long term evolution—advance (LTE-A) and digital video broadcasting—terrestrial second generation (DVB-T2) technologies. Those geographical areas that are not covered because the useful DTT signal is obstructed by the environment or it has a limited coverage by the network design can be called “micro-TVWS.” We assume that a DVB-T2 transmitter provides coverage for fixed rooftop reception as a primary service, to a building in which a LTE-A femtocell is installed indoors for local coverage, as a secondary service. The results have been obtained by laboratory emulation and validated through field measurements using professional equipment. Our results provide the technical restrictions of the LTE-A femtocell, mainly on the maximum allowable effective isotropic radiated power that could transmit on the DTT band in terms of carrier separation, from co-channel to adjacent band. These results meet the need of spectrum for IMT-Advanced technologies, so spectrum sharing is proposed in this paper as a new solution to make an efficient use of this resource.

A South African perspective on value-added tax on international mobile telecommunication services

The purpose of the article is to explore the VAT practices of mobile telecommunication service providers in South Africa. First, literature dealing with the general VAT principles in South Africa such as the VAT Act No. 89 of 1991 and that of other countries was considered, where after the Melbourne Agreement, which specifically deals with the VAT on international telecommunication services, was considered. As the provisions of the general VAT principles as portrayed in the VAT Act (89/1991) and those of the Melbourne Agreement differ, the tax managers at three major South African telecommunication service providers were interviewed to determine which principles they apply in practice. From the interviews conducted, it was clear that South African telecommunication service providers apply the principles of the Melbourne Agreement and levy VAT at 14% on international telecommunications services provided to its customers and VAT at 0% to foreign network operators for services rendered to non-residents while in South Africa. This is, however, contrary to the normal VAT principles that a service is zero-rated when a service is exported and consumed outside of South Africa and VAT levied at 14% when the service is provided to a non-resident present in South Africa at the time the service is rendered.

On 5G radio access architecture and technology [Industry Perspectives

In early 2012, the International Telecommunication Union (ITU) under the United Nations initiated a program to develop an International Mobile Telecommunication (IMT) system for 2020 and beyond (IMT-2020), thereby officially kicking off the global race toward a yet to be defined fifth generation (5G) mobile network. Fast forward three years, the vision of this next-generation system is beginning to take shape. A recent ITU-Radiocommunication Standardization Sector (ITU-R) Draft Recommendation [1] on IMT-2020 identifies three key usage scenarios in 5G as enhanced mobile broadband, massive machine-type communications, and ultra-reliable and low-latency communications. The same report also issues guidance on the requirements for these scenarios in terms of performance index such as spectrum efficiency, latency, connection density, and area traffic capacity, as shown in Fig. 1. In order to meet these requirements and bring this visionary system to reality, we believe that the future 5G network will be one that is built on a small cell backbone. As spectrum suitable for mobile communication becomes more and more scarce, densification is the only way to meet the area traffic capacity demand. Even for millimeter-wave band, where spectrum is abundant, the channel’s propagation characteristics will likely limit its range for mobile access to that of a small cell, at least in the early phase of 5G before device technology matures. The small cell also brings the radio access point closer to the end device, thereby shortening the last and most challenging segment of an end-to-end communication link, consequently reducing latency and increasing reliability. Many of the massive number of machine-type communications can also benefit from the extended battery life resulting from shorter uplink distance. To facilitate the deployment of a future mobile network that has the small cell as its primary traffic bearing workhorse,the current radio access architecture needs to undergo some major revamping, and new technologies need to be introduced.