Software radio structure for second generation mobile communication systems

In this paper, we present a novel approach for using the smart antennas (SA) to exploit the space diversity for the next generations of mobile communication systems. We propose a combination of the MUltiple SIgnal Classification (MUSIC) and the Least Mean Squares (LMS) algorithms in one algorithm named MLMS. We propose the MUSIC algorithm for finding the direction of the users in the cell while we consider the LMS algorithm for enhancing the accuracy of the obtained Direction of Arrival (DOA) angles, performing the beam generation process, and keep tracking of the users in the cell. Furthermore, we propose a scheduling algorithm that performs the scheduling in terms of the generated beams. The space diversity, together with the time and frequency diversities of LTE (Long Term Evaluation) provide a large capacity enhancement to the next generations of wireless mobile communication systems. Our simulation results show that our novel approach has the capability to converge and completely follow the desired user signal with a very high resolution. The convergence and the accurate tracking of the desired user signal take place after 13 iterations while in the traditional LMS, the convergence needs 85 iterations to take place. This means 84.7% improvement over the traditional LMS algorithm for the same number of calculations in each iteration. In addition, our proposed scheduling scheme based on beamforming shows a gain of around 15% in the total aggregated data rate for each 10° decrease in the beam size.

Currently, the standardization of fifth generation mobile communication system (5G), which realizes 10 Gbps transmission, is in progress. In mobile communications, it is generally difficult to perform high-capacity transmission because of channel fading. Therefore, an adaptive resource allocation scheme based on users' channel conditions is adopted to enhance the system capacity. Recently, it has been shown that a nonorthogonal multiple access (NOMA) scheme can achieve a higher system capacity than orthogonal multiple access scheme. However, anticipating a continuous increase of mobile traffic, it is desired to further enhance the capacity of NOMA scheme. Therefore, we propose an application of code division multiplexing to NOMA scheme using successive interference canceller to improve the throughput performance. The improved performance is demonstrated through numerical simulations.

Fifth generation mobile communications system (5G) that enables large transmission capacity (over 10 Gbps) is currently standardized and under development. Non-orthogonal multiple access (NOMA) scheme is a typical core technology for 5G. On the other hand, we had proposed earlier a chaos multiple-input multiple-output (C-MIMO) transmission scheme that harnesses the strengths of the chaos communication system. C-MIMO exhibits channel coding effect and physical layer security based on a common key encryption that helps realize a secure wireless transmission. Furthermore, based on the C-MIMO, we had proposed a downlink chaos NOMA transmission scheme that realizes physical layer security in NOMA. However, in the conventional studies, an uplink transmission is not considered yet. Therefore, in this paper, we propose an uplink chaos NOMA transmission scheme using C-MIMO to realize a secure and large-capacity uplink transmission. The performance of the proposed scheme is evaluated through numerical simulations.

The paper presents methods for combining single and multi-channel fiber-optic links. On this basis, the architecture of the current and next generations of mobile communication systems, which should be strongly supported by all-optical networks, is presented. An example of a mobile system based on the EON/OTN/TSON backbone and edge optical networks operating in active and passive modes is presented. The current and future needs of mobile systems and networks were analyzed in terms of the quality of service parameters. Requirements for optical links used in separate networks of mobile systems such as NGC, BH, FH, and MH are presented. Calculations of the optical spectral efficiency of single-channel optical links used in the mobile systems were made. The calculations include the coherent modulations of single-carrier and multi-carrier OFDM formats, as well as D-RoF and A-RoF formats used in optical FH and MH. The results of the calculations are presented in diagrams. Application scenarios of the proposed network architecture and spectral effective modulation formats were discussed.

The next generation mobile communication systems, such as the International Mobile Telecommunication-2000 (LMT-2000), will introduce new technologies and services including broadband communications, soft-handovers, micro/pico cell architecture, and multicall/connection services. In this paper, we first clarify the impact of these new technologies and services on handover performance. We then propose a new handover method, in which the handover connection setup process is divided into the network connection setup and the radio connection setup parts, with the former taking place before a handover request by predicting the next cell.

Excellent reliability performance of AlGaN/GaN HEMTs on SiC substrates for next generation mobile communication systems has been demonstrated using DC and RF stress tests on 8x60 μm wide and 0.5 μm long AlGaN/GaN HEMTs at a drain voltage of V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</sub> =50V. Drain current recovery measurements after stress indicate that the degradation is partly caused by slow traps generated in the SiN passivation or in the HEMT epitaxial layers. The traps in the SiN passivation layer were characterized using high and low frequency capacitance voltage (CV) measurements of MIS test structures on thick lightly doped GaN layers.

The 5th generation mobile communication system (5G) is oriented towards a new generation of mobile communication system to the year of 2020 and beyond, and its development is still at the exploratory stage. Combining the latest trends in mobile communication development at home and abroad, in this article, we describe the key technologies of driving the 5G research direction. Furthermore, the technical innovation of 5G comes from both wireless and network technologies. In the field of wireless technologies, massive multiple-input multiple-output (MIMO), ultra-wideband spectral, ultra-dense heterogeneous networks, have already become the focus of global industry. In the field of network technologies, a new network architecture based on software-defined networking (SDN) becomes the prevailing view worldwide. Additionally, there are some other potential technologies for 5G, such as NOMA, FBMC, mm Waves, and Multi-carrier technology aggregation.

The definition of the fundamental concepts and the design of the architectural framework for network slicing in fifth-generation communication systems have been successfully concluded; the standardization activities are almost over; and the commercial deployment has already commenced worldwide. To compete for digital supremacy and to be seen as front-runners in the international technological race, researchers from various regions and countries have begun exploring the technical requirements, envisioning potential applications, identifying innovative enablers, developing testbeds for the preliminary validation of several terrestrial and non-terrestrial technologies, and conceptualizing the architectural design for the next generation of mobile communication systems -the sixth-generation (6G) -aiming to connect the human, physical, and digital worlds with a high level of intelligence and openness for the 2030s. In support of such an ambitious vision, this article extends the end-to-end network slicing concepts, methods, solutions, and functioning architectures towards 6G. To this intent, the study first presents several decisive motivating trends behind such an extension of network slicing in order to make forthcoming mobile networks fully slicing-aware. Following that, the paper attempts to highlight the intelligentization of a number of key enabling technologies that will bring a renaissance to network slicing in the next decade. It then proposes a unified architectural framework and its principal building blocks in several layers, paving the way for the implementation of an open and intelligent network and network slicing in 6G. The proposed architectural solution harmonizes the most recent specifications of the relevant de jure and de facto standards development organizations in their applicable layers with the aim of architecting a pre-standard-compliant and preliminary framework for slicing the 6G network. Finally, the article is intended to spur interest and lay the groundwork for further investigations and subsequent research and development by highlighting a number of open research challenges and directions in this flourishing field.

New generation of mobile communication systems will focus on seamlessly integrating existing wireless technologies including 3G cellular systems, wireless LAN and Bluetooth to create a wide coverage, improved capacity and enhanced QoS heterogeneous wireless communication system. It is envisaged that the next generation of wireless communication systems will support comprehensive and personalized services, providing stable system performance and quality of service. In this paper we investigate and analyse the performance of a wireless communication system which consists of an integrated cellular communication system and a wireless LAN radio access networks inorder to determine an optimum combination of radio access technologies in a coverage area for efficient handling of mixed traffic requests from mobile users.

Design of Digital Phase Shifters for Multipurpose Communication Systems aims to cover a new emerging need in designing digital phase shifters for modern communication systems. With the advancement of new generation mobile communication systems, directed beams save a substantial amount of RF-power, and improve the noise immunity. In this regard, beam-forming circuits, namely, digital phase shifters constitute essential parts the antenna arrays. Therefore, this book is devoted to design of digital phase shifters for various communications systems. In the good old days, phase shifter design requirements used to demand narrow bandwidth with no physical size constraints. Nowadays, they must be compact and suitable for Very Large Scale Integrated Circuits (VLSI) or Microwave Monolithic Integrated Circuit (MMIC) implementation with Wide Phase Range (WPR) and Wide Frequency Band (WFB). Since the 1980s, the author has been designing digital phase shifters for various applications. He started to work with loaded lines phase shifters, and then employed branch line couplers to achieve wider frequency bands. In order to reduce the physical size, he used a 3 element Symmetric LC ladder based T or PI configurations. In order to achieve broad frequency band with large phase range, usage of LC lattice structures is inevitable. Lately, the author designed phase shifters using both lowpass and highpass LC ladder and lattice based switched-structures, which are suitable for monolithic implementation. In the course of design, MOS transistors were employed as switching elements. This book includes several novel digital phase shifter topologies, which provides wide phase range and wideband operation. Technical topics discussed in the book include: • Basic Concept of Antenna Arrays • Concept of Digital Phase Bit • Scattering Parameters to analyze the electric performance of phase shifters • Transmission Lines as circuit elements to construct practical phase shifters • Loaded Line Digital Phase Shifters (DPS) • 180° - Lowpass Based T/PI Section DPS • 180° - Highpass Based T/PI Section DPS • 180° 3-Element LC T/PI Section DPS • 180° Wide Phase Range, Wide Frequency Band Symmetric Lattice Based DPS For each topology presented, explicit design equations are provided and programs to assess the electric performance of each topology is developed in a MatLab environment. It is expected that the reader will be self-sufficient to design and implement the digital phase shifters topologies presented in this book.

Internet of everything (IoE)-based smart services are expected to gain immense popularity in the future, which raises the need for next-generation wireless networks. However, 5G and Beyond 5G (B5G) will be unable to provide the complete requirements of the Internet of Everything (IoE), even that 5G networks can support various IoE services, they might not be able to completely full-fill the requirements of novel applications. Moreover, in spite of the fact that 5G is still in the underlying phase of commercial scale, it is also look forward to the communication needs of the future information society and start the idea and technology research for the next generation mobile communication system. Therefore, there is a high demand for 6G. The 6G will revolutionize personal life, lifestyle, society, business and communication systems. It is a crucial time to envision the potential applications, techniques, use cases, and challenges of 6G technology. Noteworthy, 6G will create enormous research possibilities and enable many new technologies. Moreover, the 6G will be proven as a game changer paradigm in diverse fields. 6G wireless systems are envisioned to overcome 5G network limitations, a taxonomy based on key enabling technologies, use cases, emerging machine learning schemes, communication technologies, networking technologies, and computing technologies. These key enabling technologies will aim to compete challenges and issues in the way to 6G. These include terabit data transmission system, 3D networks paradigm, availability and reliability, intelligent radio and distributed AI. A 6G mobile network system requires to deliver extremely fast speed, increase capacity then non-proximity in order to support the likelihood of fresh applications, as vigorous medicine, computer disaster forecasting plus virtual reality (VR). 6G should promote wireless technologies such as the use an advanced frequency spectrum than preceding generations to advance the data throughput estimated at 100 to 1000 times quicker than 5G. 6G systems will let hundreds of GBs per second to connect to the second using broadband spectrum; for instance, the combined usage of a band from 1 to 3 GHz, a millimeter wave band (mm wave) (30 to 300 GHz) and a terahertz band (0.06 to 10 THz). In the spatial dimension, to benefit more from multi-channel, MIMO residue techniques (PM-MIMO), as the ultra-huge MIMO (UM-MIMO) for terahertz communication, can help hundreds or thousands of antennas to transmit / receive. 6G with Satellite Network The 6G mobile system for global coverage will be coordinated 5G mobile wireless system plus the satellite network. Finally, Cell less Architecture for 6G Networks following generation wireless networks have to assist an enormous figure of terminal users within minor geographical extents, and this will stretch increase to dense or ultra-dense placement of APs/BSs with overlapping coverage zones.

Design of Digital Phase Shifters for Multipurpose Communication Systems aims to cover a new emerging need in designing digital phase shifters for modern communication systems. With the advancement of new generation mobile communication systems, directed beams save a substantial amount of RF-power, and improve the noise immunity. In this regard, beam-forming circuits, namely, digital phase shifters constitute essential parts the antenna arrays. Therefore, this book is devoted to design of digital phase shifters for various communications systems.In the good old days, phase shifter design requirements used to demand narrow bandwidth with no physical size constraints. Nowadays, they must be compact and suitable for Very Large Scale Integrated Circuits (VLSI) or Microwave Monolithic Integrated Circuit (MMIC) implementation with Wide Phase Range (WPR) and Wide Frequency Band (WFB).Since the 1980s, the author has been designing digital phase shifters for various applications. He started to work with loaded lines phase shifters, and then employed branch line couplers to achieve wider frequency bands. In order to reduce the physical size, he used a 3 element Symmetric LC ladder based T or PI configurations. In order to achieve broad frequency band with large phase range, usage of LC lattice structures is inevitable. Lately, the author designed phase shifters using both lowpass and highpass LC ladder and lattice based switched-structures, which are suitable for monolithic implementation. In the course of design, MOS transistors were employed as switching elements. This book includes several novel digital phase shifter topologies, which provides wide phase range and wideband operation.Technical topics discussed in the book include:- Basic Concept of Antenna Arrays- Concept of Digital Phase Bit- Scattering Parameters to analyze the electric performance of phase shifters- Transmission Lines as circuit elements to construct practical phase shifters- Loaded Line Digital Phase Shifters (DPS)- Lowpass Based T/PI Section DPS- Highpass Based T/PI Section DPS- 3-Element LC T/PI Section DPS- Wide Phase Range, Wide Frequency Band Symmetric Lattice Based DPSFor each topology presented, explicit design equations are provided and programs to assess the electric performance of each topology is developed in a MatLab environment. It is expected that the reader will be self-sufficient to design and implement the digital phase shifters topologies presented in this book.

FinFET and UTBB for RF SOI communication systems

Printed antennas are becoming one of the most popular designs in personal wireless communications systems. In this paper, the design of a novel tapered meander line antenna is presented. The design analysis and characterization of the antenna is performed using the finite difference time domain technique and experimental verifications are performed to ensure the effectiveness of the numerical model. The new design features an operating frequency of 2.55 GHz with a 230 MHz bandwidth, which supports future generations of mobile communication systems.

In the next generation of mobile communication systems, high data rates and high capacity will be possible if multiple antennas are used at new frequencies. This paper presents the correlations between channel parameter path loss (PL), root mean square delay spread (DS), angular spread (AS), and K-factor established based on channel measurements. The channel measurements were performed in a 781MHz LOS/NLOS environment. To avoid interference from Korean DTV broadcasting, we measured the channel characteristics in urban/rural/suburban areas on Jeju Island using a channel sounder and 4×4 antennas. The correlations between channel parameter show that the wireless channel characteristics can be determined and effective communication system design can be produced for use in similar environments.