Download or read book Millimeter Wave Link Configuration with Hybrid MIMO Architectures written by Javier Rodríguez-Fernández and published by . This book was released on 2020 with total page 546 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of multiple antennas, widely known as MIMO technology, is a key feature to deploy mmWave communication systems enabling high-data-rate applications. With more than two decades of global experience in deploying Wi-Fi and cellular communication using sub-6 GHz frequency bands, simply repurposing these designs for mmWave bands would fail to account for additional propagation impairments and circuit design constraints at these higher frequencies. A solution to overcome the propagation challenges is the use of multiple directional communication beams, whereby proper alignment between transceivers provides sufficient link quality to enable reliable decoding of the transmitted data. In this dissertation, efficient link configuration solutions suitable for mmWave cellular communications are developed. To gain some insight into the achievable performance of mmWave systems, two broadband channel-estimation-based link configuration solutions are proposed for MIMO-OFDM systems, in which both the transmitter and receiver are assumed to be perfectly synchronized. The proposed solution exploits the spatially common sparsity in the mmWave channel and enables efficient acquisition of the CSI while allowing the use of multiple RF chains on both the transmitter and receiver sides. In a simplified scenario, the CRLB for the channel estimation problem is derived, and the proposed channel estimation algorithms are shown to both outperform prior work in communication performance and exhibit excellent estimation performance. Furthermore, the proposed algorithms are assessed in a more challenging scenario with realistic channel parameters, and it is shown that both near-optimal spectral efficiency and low BER can be attained with lower overhead and computational complexity than prior solutions. Next, the impact of imperfect CFO synchronization on the channel estimation problem is analyzed under a narrowband channel model. The CRLB for the estimation of the different unknown parameters involved in the problem is theoretically analyzed, and closed-form expressions are provided for the estimation of the different parameters. Under a joint estimation-theoretic and CS framework, a low-complexity multi-stage solution is proposed to estimate both the different unknown synchronization parameters and the large-dimensional mmWave MIMO channel. Different trade-offs between estimation, spectral efficiency, and overhead performance are exposed, and the proposed estimators are shown to be asymptotically optimal in the low SNR regime. The proposed solution is assessed under a channel model with several clusters and rays per cluster, and is shown to attain near-optimal spectral efficiency values in both the low and high SNR regimes. The computational complexity of the proposed solution is also analyzed, in which it is shown to achieve a marginal increase in computational complexity with respect to the solution proposed in the previous contribution. Finally, the impact of TO, CFO, and PN impairments on the channel estimation problem is analyzed under a broadband channel model. The problem of time-frequency synchronization under PN impairments is theoretically analyzed, and the proposed solutions to the synchronization problem are exploited to estimate the frequency-selective mmWave MIMO channel. The hybrid CRLB for the estimation of the different synchronization impairments is analyzed, and closed-form expressions leveraging the information coupling between the different impairments are provided. The previously proposed joint estimation-theoretic and CS framework is extended to frequency-selective scenarios, and two low-complexity multi-stage solutions are proposed to estimate both the different synchronization impairments and the large-dimensional mmWave MIMO channel. The first solution relies on a batch-processing LMMSE-based EM algorithm to estimate the different synchronization impairments, while the second solution uses a sequential-processing EKF-RTS-based EM algorithm, thereby reducing computational complexity. Thereafter, both the hybrid CRLB for the estimation of the equivalent beamformed complex channels and the estimates for these parameters are exploited to estimate the large-dimensional frequency-selective mmWave MIMO channel. Finally, a joint PN and data detection algorithm is proposed for data transmission under the 5G NR frame structure. The proposed solutions are evaluated using a 5G NR-based channel model, and different trade-offs between estimation performance, computational complexity, overhead, achievable spectral efficiency and BER are exposed, and comparisons with prior work are also provided. The results show that mmWave link configuration using hybrid MIMO architectures can be established with low overhead without assuming synchronization, even in the low SNR regime

Download or read book Millimeter Wave Link Configuration in Practical Scenarios written by Hongxiang Xie (Ph. D.) and published by . This book was released on 2021 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt: Acquiring channel state information (CSI) for link configuration in wideband millimeter wave (mmWave) massive multiple-input-multiple-output (MIMO) systems with hybrid architectures is challenging, due to the high dimensions of the channel matrices, the low signal-to-noise ratio (SNR) before beamforming, the various hardware constraints and the high mobility in the vehicular context. Previous work in this area exploits channel sparsity, statistical priors or side information to reduce the overhead associated to initial channel estimation or channel tracking. These works consider, however, a system model that neglects hardware imperfections. In addition, many of the proposed solutions are unable to operate in some realistic scenarios, such as vehicle-to-everything (V2X) communications. In this dissertation, we develop new signal processing solutions that can enable low-overhead mmWave link configuration under various disturbances and practical limitations, e.g., hardware impairments, calibration errors, beam squint effect, channel blockage, high mobility, to name a few. In the first part of this dissertation, we focus on the problem of wideband channel estimation for mmWave MIMO systems with different hardware imperfections. We first design a dictionary learning aided channel estimation strategy for wideband mmWave MIMO systems by explicitly considering the hardware uncertainties and calibration errors, and then derive algorithms that learn the optimal sparsifying dictionaries for channel representation and estimation. In a second contribution of this part, we further develop a dictionary learning aided compressive channel estimation scheme for mmWave MIMO systems by incorporating beam squint into the model of array responses. Numerical results show the proposed solutions can adapt to the practical scenarios and help reduce the overhead associated with channel estimation significantly. In the second part of this dissertation, we deal with the problem of wideband channel tracking for mmWave MIMO systems with or without the impact of blockage. We first introduce statistical channel models that include the evolution models for channel gains and angles of arrival/departure, as well as the statistics of blockage events. Then, we design novel blockage detection schemes and efficient Bayesian channel tracking algorithms to facilitate the low-overhead tracking with or without blockage. Numerical results corroborate that the proposed solutions achieve better channel tracking performance even in mobile scenarios that suffer from highly dynamic blockage events

Download or read book mmWave Massive MIMO written by Shahid Mumtaz and published by Academic Press. This book was released on 2016-12-02 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: mmWave Massive MIMO: A Paradigm for 5G is the first book of its kind to hinge together related discussions on mmWave and Massive MIMO under the umbrella of 5G networks. New networking scenarios are identified, along with fundamental design requirements for mmWave Massive MIMO networks from an architectural and practical perspective. Working towards final deployment, this book updates the research community on the current mmWave Massive MIMO roadmap, taking into account the future emerging technologies emanating from 3GPP/IEEE. The book's editors draw on their vast experience in international research on the forefront of the mmWave Massive MIMO research arena and standardization. This book aims to talk openly about the topic, and will serve as a useful reference not only for postgraduates students to learn more on this evolving field, but also as inspiration for mobile communication researchers who want to make further innovative strides in the field to mark their legacy in the 5G arena. - Contains tutorials on the basics of mmWave and Massive MIMO - Identifies new 5G networking scenarios, along with design requirements from an architectural and practical perspective - Details the latest updates on the evolution of the mmWave Massive MIMO roadmap, considering future emerging technologies emanating from 3GPP/IEEE - Includes contributions from leading experts in the field in modeling and prototype design for mmWave Massive MIMO design - Presents an ideal reference that not only helps postgraduate students learn more in this evolving field, but also inspires mobile communication researchers towards further innovation

Download or read book Signal Processing for Joint Radar Communications written by Kumar Vijay Mishra and published by John Wiley & Sons. This book was released on 2024-04-09 with total page 453 pages. Available in PDF, EPUB and Kindle. Book excerpt: Signal Processing for Joint Radar Communications A one-stop, comprehensive source for the latest research in joint radar communications In Signal Processing for Joint Radar Communications, four eminent electrical engineers deliver a practical and informative contribution to the diffusion of newly developed joint radar communications (JRC) tools into the sensing and communications communities. This book illustrates recent successes in applying modern signal processing theories to core problems in JRC. The book offers new results on algorithms and applications of JRC from diverse perspectives, including waveform design, physical layer processing, privacy, security, hardware prototyping, resource allocation, and sampling theory. The distinguished editors bring together contributions from more than 40 leading JRC researchers working on remote sensing, electromagnetics, optimization, signal processing, and beyond 5G wireless networks. The included resources provide an in-depth mathematical treatment of relevant signal processing tools and computational methods allowing readers to take full advantage of JRC systems. Readers will also find: Thorough introductions to fundamental limits and background on JRC theory and applications, including dual-function radar communications, cooperative JRC, distributed JRC, and passive JRC Comprehensive explorations of JRC processing via waveform analyses, interference mitigation, and modeling with jamming and clutter Practical discussions of information-theoretic, optimization, and networking aspects of JRC In-depth examinations of JRC applications in cutting-edge scenarios including automotive systems, intelligent reflecting surfaces, and secure parameter estimation Perfect for researchers and professionals in the fields of radar, signal processing, communications, information theory, networking, and electronic warfare, Signal Processing for Joint Radar Communications will also earn a place in the libraries of engineers working in the defense, aerospace, wireless communications, and automotive industries.

Download or read book Millimeter Wave Link Configuration Using Out of band Information written by Anum Ali and published by . This book was released on 2019 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: Millimeter wave (mmWave) communication is one feasible solution for high data-rate applications like vehicular-to-everything (V2X) communication and next-generation cellular communication. Configuring mmWave links, which can be done through channel estimation or beam-selection, however, is a source of significant overhead. Typically some structure in the channel is exploited (for beam-selection or channel estimation) to reduce training overhead. In this dissertation, we use side-information coming from some frequency band other than the mmWave communication band to reduce the mmWave training overhead. We call such side-information out-of-band information. We use the out-of-band information coming from (i) lower frequency (i.e., sub-6 GHz) communication channels, and (ii) mmWave radar. Sub-6 GHz frequencies are a feasible out-of-band information source as mmWave systems are deployed with low-frequency systems (for control signaling or multi-band communication). Similarly, radar is a feasible out-of-band information source as future vehicles and road-side units (RSUs) will likely have automotive radars. We outline strategies to incorporate sub-6 GHz information in mmWave systems - through beam-selection and covariance estimation - while considering the practical constraints on the hardware of mmWave systems (e.g., analog-only or hybrid analog/digital architecture). We also use a passive radar receiver at the RSU to reduce the training overhead of establishing an mmWave communication link. Specifically, the passive radar taps the transmissions from the automotive radars of the vehicles on road. The spatial covariance of the received radar signals is, in turn, used to establish the communication link. The results show that out-of-band information from sub-6 GHz channels and radar reduces the training overhead of mmWave link configuration considerably, and makes mmWave communication feasible in highly dynamic environments

Download or read book Millimeter Wave mmWave Communications written by Manuel García Sanchez and published by MDPI. This book was released on 2020-03-25 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: The millimeter-wave frequency band (30–300 GHz) is considered a potential candidate to host very high data rate communications. First used for high capacity radio links and then for broadband indoor wireless networks, the interest in this frequency band has increased as it is proposed to accommodate future 5G mobile communication systems. The large bandwidth available will enable a number of new uses for 5G. In addition, due to the large propagation attenuation, this frequency band may provide some additional advantages regarding frequency reuse and communication security. However, a number of issues have to be addressed to make mm-wave communications viable. This book collects a number of contributions that present solutions to these challenges.

Download or read book Massive MIMO written by Hien Quoc Ngo and published by Linköping University Electronic Press. This book was released on 2015-01-16 with total page 69 pages. Available in PDF, EPUB and Kindle. Book excerpt: The last ten years have seen a massive growth in the number of connected wireless devices. Billions of devices are connected and managed by wireless networks. At the same time, each device needs a high throughput to support applications such as voice, real-time video, movies, and games. Demands for wireless throughput and the number of wireless devices will always increase. In addition, there is a growing concern about energy consumption of wireless communication systems. Thus, future wireless systems have to satisfy three main requirements: i) having a high throughput; ii) simultaneously serving many users; and iii) having less energy consumption. Massive multiple-input multiple-output (MIMO) technology, where a base station (BS) equipped with very large number of antennas (collocated or distributed) serves many users in the same time-frequency resource, can meet the above requirements, and hence, it is a promising candidate technology for next generations of wireless systems. With massive antenna arrays at the BS, for most propagation environments, the channels become favorable, i.e., the channel vectors between the users and the BS are (nearly) pairwisely orthogonal, and hence, linear processing is nearly optimal. A huge throughput and energy efficiency can be achieved due to the multiplexing gain and the array gain. In particular, with a simple power control scheme, Massive MIMO can offer uniformly good service for all users. In this dissertation, we focus on the performance of Massive MIMO. The dissertation consists of two main parts: fundamentals and system designs of Massive MIMO. In the first part, we focus on fundamental limits of the system performance under practical constraints such as low complexity processing, limited length of each coherence interval, intercell interference, and finite-dimensional channels. We first study the potential for power savings of the Massive MIMO uplink with maximum-ratio combining (MRC), zero-forcing, and minimum mean-square error receivers, under perfect and imperfect channels. The energy and spectral efficiency tradeoff is investigated. Secondly, we consider a physical channel model where the angular domain is divided into a finite number of distinct directions. A lower bound on the capacity is derived, and the effect of pilot contamination in this finite-dimensional channel model is analyzed. Finally, some aspects of favorable propagation in Massive MIMO under Rayleigh fading and line-of-sight (LoS) channels are investigated. We show that both Rayleigh fading and LoS environments offer favorable propagation. In the second part, based on the fundamental analysis in the first part, we propose some system designs for Massive MIMO. The acquisition of channel state information (CSI) is very importantin Massive MIMO. Typically, the channels are estimated at the BS through uplink training. Owing to the limited length of the coherence interval, the system performance is limited by pilot contamination. To reduce the pilot contamination effect, we propose an eigenvalue-decomposition-based scheme to estimate the channel directly from the received data. The proposed scheme results in better performance compared with the conventional training schemes due to the reduced pilot contamination. Another important issue of CSI acquisition in Massive MIMO is how to acquire CSI at the users. To address this issue, we propose two channel estimation schemes at the users: i) a downlink "beamforming training" scheme, and ii) a method for blind estimation of the effective downlink channel gains. In both schemes, the channel estimation overhead is independent of the number of BS antennas. We also derive the optimal pilot and data powers as well as the training duration allocation to maximize the sum spectral efficiency of the Massive MIMO uplink with MRC receivers, for a given total energy budget spent in a coherence interval. Finally, applications of Massive MIMO in relay channels are proposed and analyzed. Specifically, we consider multipair relaying systems where many sources simultaneously communicate with many destinations in the same time-frequency resource with the help of a massive MIMO relay. A massive MIMO relay is equipped with many collocated or distributed antennas. We consider different duplexing modes (full-duplex and half-duplex) and different relaying protocols (amplify-and-forward, decode-and-forward, two-way relaying, and one-way relaying) at the relay. The potential benefits of massive MIMO technology in these relaying systems are explored in terms of spectral efficiency and power efficiency.

Download or read book Millimeter Wave MIMO written by Eric G. Torkildson and published by . This book was released on 2010 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unlicensed spectrum at 60 GHz and the E-band frequencies spans multiple GHz, enabling wireless links to reach multi-Gb/s speeds. In this work, we propose increasing speeds further by leveraging spatial multiplexing gains at millimeter (mm) wave. To this end, we design and evaluate practical MIMO architectures that address the unique challenges and opportunities associated with mm wave communication. We begin by recognizing that the mm wave channel is predominantly line-of-sight (LOS), and develop arrays that provide robust spatial multiplexing gains in this environment. Noting that the cost and power consumption of ADCs become limiting factors as bandwidths scale to multiple GHz, we then propose a hierarchical approach to MIMO signal processing. Spatial processing, including beamforming and spatial multiplexing, is performed on a slow time scale and followed by separate temporal processing of each of the multiplexed data streams. This design is implemented in a four-channel hardware prototype.

Download or read book Millimeter Wave Wireless Communications written by Theodore S. Rappaport and published by Pearson Education. This book was released on 2015 with total page 705 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Definitive, Comprehensive Guide to Cutting-Edge Millimeter Wave Wireless Design “This is a great book on mmWave systems that covers many aspects of the technology targeted for beginners all the way to the advanced users. The authors are some of the most credible scholars I know of who are well respected by the industry. I highly recommend studying this book in detail.” —Ali Sadri, Ph.D., Sr. Director, Intel Corporation, MCG mmWave Standards and Advanced Technologies Millimeter wave (mmWave) is today's breakthrough frontier for emerging wireless mobile cellular networks, wireless local area networks, personal area networks, and vehicular communications. In the near future, mmWave products, systems, theories, and devices will come together to deliver mobile data rates thousands of times faster than today's existing cellular and WiFi networks. In Millimeter Wave Wireless Communications, four of the field's pioneers draw on their immense experience as researchers, entrepreneurs, inventors, and consultants, empowering engineers at all levels to succeed with mmWave. They deliver exceptionally clear and useful guidance for newcomers, as well as the first complete desk reference for design experts. The authors explain mmWave signal propagation, mmWave circuit design, antenna designs, communication theory, and current standards (including IEEE 802.15.3c, Wireless HD, and ECMA/WiMedia). They cover comprehensive mmWave wireless design issues, for 60 GHz and other mmWave bands, from channel to antenna to receiver, introducing emerging design techniques that will be invaluable for research engineers in both industry and academia. Topics include Fundamentals: communication theory, channel propagation, circuits, antennas, architectures, capabilities, and applications Digital communication: baseband signal/channel models, modulation, equalization, error control coding, multiple input multiple output (MIMO) principles, and hardware architectures Radio wave propagation characteristics: indoor and outdoor applications Antennas/antenna arrays, including on-chip and in-package antennas, fabrication, and packaging Analog circuit design: mmWave transistors, fabrication, and transceiver design approaches Baseband circuit design: multi–gigabit-per-second, high-fidelity DAC and ADC converters Physical layer: algorithmic choices, design considerations, and impairment solutions; and how to overcome clipping, quantization, and nonlinearity Higher-layer design: beam adaptation protocols, relaying, multimedia transmission, and multiband considerations 60 GHz standardization: IEEE 802.15.3c for WPAN, Wireless HD, ECMA-387, IEEE 802.11ad, Wireless Gigabit Alliance (WiGig)

Download or read book Hybrid Analog digital Signal Processing for MmWave Massive MIMO Communications written by Alireza Morsali and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Massive multiple-input multiple-output (MIMO) and millimeter-wave (mmWave) communications are established as key technologies for fifth generation (5G) and beyond (5G\&B) networks. However, the practical implementation of mmWave massive-MIMO systems remains challenging. Conventional MIMO systems are implemented using the fully-digital (FD) architecture, in which signal processing is performed in the digital domain by means of dedicated processors and/or digital circuitry. At the transmitter, the digital baseband output signals are then converted to analog signals for transmission, which requires a dedicated radio frequency (RF) chain per antenna element. For the large-scale antenna arrays envisaged for massive-MIMO systems, however, the FD architecture is impractical due to the huge power consumption and production costs.One the most effective solutions to this problem is hybrid analog/digital (A/D) beamforming (HBF). In this approach, an additional signal processing layer in the analog domain, referred to as analog beamformer, is added between the RF chains and the antenna elements. In effect, by properly designing the analog beamformer, it becomes possible to reduce the number of RF chains while achieving a performance comparable to the FD architecture.There are three parts to this thesis all of which have a common goal, which is to achieve the performance of FD systems with HBF. In the first part, we consider HBF at the transmitter side and study the minimum number of required RF chains for realizing a given FD~precoder with the \hp~architecture. We further investigate HBF designs based on the single RF chain architecture for mmWave massive-MIMO systems. We present three novel beamformer designs which achieve the performance of FD precoding systems. Finally, we extend these results to MIMO-OFDM systems.The second part studies HBF at the receiver. Particularly, we propose a novel hybrid structure for realizing a given FD combiner with the minimum number of required RF chains.We then focus on a more practical scenario where phase-shifters can realize a finite number of phase angles. Accordingly, we propose a modified hybrid structure by introducing an additional degree of freedom, i.e., phase-offset between the finite-resolution phase-shifts and optimize this parameter via close approximations. Robust hybrid combiners are then studied for the case of imperfect channel knowledge at the receiver.In the final part of this thesis, we explore the hybrid A/D structure as a general framework for signal processing in massive and ultra-massive-MIMO systems. To exploit the full potential of the analog domain, we first focus on the analog signal processing (ASP) network. We investigate a mathematical representation suitable for any arbitrarily connected feed-forward ASP network comprised of the common RF hardware elements in the context of hybrid A/D systems, i.e., phase-shifter and power-divider/combiner. A novel ASP structure is then proposed which is not bound to the unit modulus constraint, thereby facilitating the hybrid A/D systems design. We then study MIMO transmitter and receiver designs to exploit the full potential of digital processing as well.An optimization model based on the proposed structure is presented that can be used for hybrid A/D system design. Finally, precoding and combining designs under different conditions are discussed as examples"--

Download or read book Millimeter Wave and Massive MIMO Communications for Next generation Wireless Systems written by Ahmed Abulkareem Nageeb Youssef Alkhateeb and published by . This book was released on 2016 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multiple-input multiple-output (MIMO) communication is expected to play a central role in future wireless systems through the deployment of a large number of antennas at the transmitters and receivers. In low-frequency systems, massive MIMO offers high multiplexing gains that boost system spectral efficiency. In millimeter wave (mmWave) systems, the deployment of large antenna arrays at both the base station and mobile users is necessary to guarantee sufficient received signal power. Realizing these systems in practice, however, requires addressing several key challenges: (i) fully-digital solutions are costly and power hungry, (ii) channel training and estimation process has high overhead, and (iii) precoders design optimization problems are non-trivial. In this dissertation, precoding and channel estimation strategies that address these challenges are proposed for both mmWave and massive MIMO systems. The proposed solutions adopt hybrid analog/digital architectures that divide precoding/combining processing between RF and baseband domains and lead to savings in cost and power consumption. Further, the developed techniques leverage the structure and characteristics of mmWave and massive MIMO channels to reduce the training overhead and precoders design complexity. The main contributions of this dissertation are (i) developing a channel estimation solution for hybrid architecture based mmWave systems, exploiting the sparse nature of the mmWave channels, (ii) designing hybrid precoding algorithm for multi-user mmWave and massive MIMO systems, (iii) proposing a multi-layer precoding framework for massive MIMO cellular systems, and (iv) developing hybrid precoding and codebook solutions for frequency selective mmWave systems. Mathematical analysis as well as numerical simulations illustrate the promising performance of the proposed solutions, marking them as enabling technologies for mmWave and massive MIMO systems.

Download or read book Designing and Evaluating of MIMO Systems for Millimeter wave Communications written by Mojtaba Ahmadi Almasi and published by . This book was released on 2020 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The fifth generation (5G) of wireless communications will integrate all existing technologies while bringing its own to the system. Amongst these technologies, millimeter-wave (mmWave) is emerging as a promising solution for 5G systems. However, to fully harness the potential of mmWave communications, obstacles such as severe path loss, channel sparsity, and hardware complexity should be overcome. The existing cost-effective systems can considerably reduce the hardware complexity and partially severe path loss, while channel sparsity still remains a main problem. Other factors such as transmission reliability and coverage area should be considered in 5G mmWave communications. Non-orthogonal multiple access (NOMA) is another enabling technology for 5G systems to improve spectral efficiency through serving more than one user at the same time/frequency/code resources. In particular, users' signals are superimposed in power domains at the transmitter which allows for simultaneously exploiting the available resources. Therefore, mmWave bands along with NOMA plays a crucial role in 5G wireless communications. Aiming to overcome the mentioned obstacles, in the first part of this dissertation, we design a new lens-based reconfigurable antenna multiple-input multiple-output (RA-MIMO) architecture that takes advantage of multi-beam antennas for point-to-point communications. The considered antennas can generate multiple independent beams simultaneously using a single RF chain. This property, together with RA-MIMO architecture, is used to combat small-scale fading and shadowing in mmWave bands. We use well-known space-time block codes (STBCs), together with phase-shifters at the receiver, in the RA-MIMO to suppress the effect of small-scale fading and shadowing. We also study the impact of practical quantized phase-shifters on the performance of the proposed RA-MIMO. On the other hand, to make the most of these multi-beam antennas, a novel multiple access technique is developed for multi-user scenarios named reconfigurable antenna multiple access (RAMA). This technique transmits only each user's intended signal at the same time/frequency/code. This property makes RAMA an inter-user interference-free technique. Further, we integrate the well-known non-orthogonal multiple access (NOMA) technique in the proposed and other available mmWave systems. Moreover, to support a huge number of groups of users, we integrate RAMA into NOMA named reconfigurable antenna NOMA (RA-NOMA). This new technique divides the users with respect to their angle of departures (AoDs) and channel gains. Users with different AoDs and comparable channel gains are served via RAMA while users with the same AoDs but different channel gains are served via NOMA. In the second part of this dissertation, we investigate NOMA in mmWave MIMO systems with phased array antennas. Two major obstacles in implementing NOMA are beam misalignment and limited channel coherence time due to the directional transmission. First, the effect of beam misalignment on rate performance in downlink of hybrid beamforming-based NOMA (HB-NOMA) systems is studied. To this end, an HB-NOMA framework is designed and a sum-rate maximization problem is formulated. An algorithm is introduced to design digital and analog precoders and efficient power allocation. Then, regarding perfectly aligned line-of-sight (LoS) channels, a lower bound for the achievable rate is derived. When the users experience misaligned LoS or non-LoS (NLoS) channels, the impact of beam misalignment is evaluated. We take the limited channel coherence time into account for non-orthogonal multiple access (NOMA) in mmWave hybrid beamforming systems. Due to the limited coherence time, the beamwidth of the hybrid beamformer affects the beam-training time, which in turn directly impacts the data transmission rate. To investigate this trade-off, we utilize a combined beam-training algorithm. Then, we formulate a sum-rate expression which considers the channel coherence time and beam-training time as well as users' power and other system parameters."--Boise State University ScholarWorks.

Download or read book Millimeter Wave Antennas Configurations and Applications written by Jaco du Preez and published by Springer. This book was released on 2016-06-20 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book comprehensively reviews the state of the art in millimeter-wave antennas, traces important recent developments and provides information on a wide range of antenna configurations and applications. While fundamental theoretical aspects are discussed whenever necessary, the book primarily focuses on design principles and concepts, manufacture, measurement techniques, and practical results. Each of the various antenna types scalable to millimeter-wave dimensions is considered individually, with coverage of leaky-wave and surface-wave antennas, printed antennas, integrated antennas, and reflector and lens systems. The final two chapters address the subject from a systems perspective, providing an overview of supporting circuitry and examining in detail diverse millimeter-wave applications, including high-speed wireless communications, radio astronomy, and radar. The vast amount of information now available on millimeter-wave systems can be daunting for researchers and designers entering the field. This book offers readers essential guidance, helping them to gain a thorough understanding based on the most recent research findings and serving as a sound basis for informed decision-making.

Download or read book Millimeter Wave Wearable Communication Networks written by Kiran Venugopal and published by . This book was released on 2017 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: Future high-end wearable electronic devices including virtual reality goggles and augmented reality glasses require rates of the order of gigabits-per-second and potentially very low latency. Supporting high data rate wireless connectivity for applications such as uncompressed video streaming among wearable devices in a densely crowded environment is challenging. This is primarily due to bandwidth scarcity when many users operate multiple devices simultaneously. The millimeter wave (mmWave) band has the potential to address this bottleneck, thanks to more spectrum and less interference because of signal blockage at these frequencies. This dissertation addresses key questions that need to be answered before realizing mmWave-based wearables in practice: (i) what are the expected achievable rates in a crowded user environment, with mmWave devices using a given hardware configuration? (ii) how is the wireless connectivity affected in an indoor operation, which is prone to surface reflections? (iii) can multi-stream data transmission, involving large bandwidth communication under hardware constraints be realized? To answer these, tools from stochastic geometry and compressive sensing, and architectures involving hybrid analog/digital multiple-input multiple-output (MIMO) are leveraged. The main contributions of this dissertation are 1) analytical modeling to compute average achievable rates in mmWave wearable networks consisting of finite number of user devices and human blockages, 2) characterizing the impact of reflections and non-isotropic performance of mmWave wearable networks in crowded indoor environments, 3) channel estimation to support MIMO for wideband mmWave wearable devices using hybrid architecture, and 4) designing optimal, but easy-to-implement, precoding/combining strategies in frequency-selective mmWave systems. Both analysis and numerical simulations show how the proposed evaluation methodology and solutions serve to enable mmWave based communication among next generation wearable electronic devices.

Download or read book UAV Communications for 5G and Beyond written by Yong Zeng and published by John Wiley & Sons. This book was released on 2020-12-08 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt: Explore foundational and advanced issues in UAV cellular communications with this cutting-edge and timely new resource UAV Communications for 5G and Beyond delivers a comprehensive overview of the potential applications, networking architectures, research findings, enabling technologies, experimental measurement results, and industry standardizations for UAV communications in cellular systems. The book covers both existing LTE infrastructure, as well as future 5G-and-beyond systems. UAV Communications covers a range of topics that will be of interest to students and professionals alike. Issues of UAV detection and identification are discussed, as is the positioning of autonomous aerial vehicles. More fundamental subjects, like the necessary tradeoffs involved in UAV communication are examined in detail. The distinguished editors offer readers an opportunity to improve their ability to plan and design for the near-future, explosive growth in the number of UAVs, as well as the correspondingly demanding systems that come with them. Readers will learn about a wide variety of timely and practical UAV topics, like: Performance measurement for aerial vehicles over cellular networks, particularly with respect to existing LTE performance Inter-cell interference coordination with drones Massive multiple-input and multiple-output (MIMO) for Cellular UAV communications, including beamforming, null-steering, and the performance of forward-link C&C channels 3GPP standardization for cellular-supported UAVs, including UAV traffic requirements, channel modeling, and interference challenges Trajectory optimization for UAV communications Perfect for professional engineers and researchers working in the field of unmanned aerial vehicles, UAV Communications for 5G and Beyond also belongs on the bookshelves of students in masters and PhD programs studying the integration of UAVs into cellular communication systems.

Download or read book Low Complexity Hybrid RF Beam Tracking and Baseband Precoding for Millimeter Wave MIMO Systems Algorithms and Architectures written by 許凱能 and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Millimeter Wave Link Configuration Robust to Radio Frequency Impairments written by Nitin Jonathan Myers and published by . This book was released on 2020 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: Millimeter wave (mmWave) bands offer several gigahertz of bandwidth that can support high data rate applications. To efficiently use the spectrum at mmWave frequencies, the wireless link between the transmitting and receiving radios must be configured properly. The link configuration problem at mmWave, however, is challenging due to the use of large antenna arrays and radio frequency (RF) impairments that are less severe in common lower frequency systems. Some of these impairments include the low resolution of RF phase shifters, carrier frequency offset, and the misfocus effect in near field systems with large arrays. An important characteristic of mmWave multiple-input multiple-output (MIMO) channels is sparsity. The sparse nature of such channels has allowed the use of compressed sensing (CS) for fast link configuration through channel estimation or beam alignment. CS techniques usually involve random sensing matrices to acquire a compressed channel representation and an optimization algorithm to estimate the sparse channel. Unfortunately, common random CS matrices result in poor link configuration under RF impairments. In the first part of this dissertation, we construct a new class of CS matrices that achieve robustness to the low resolution of RF phase shifters and the carrier frequency offset. To aid our construction, we propose a framework called FALP and develop an algorithm called Swift-Link within this framework. Swift-Link achieves better beam alignment than standard CS-based solutions at a reduced computational complexity. In the second part of this dissertation, we investigate the misfocus effect in near field beamforming. The beams in a near field communication scenario can focus RF signals in a spatial region called the focal point. The focal point, however, changes with the frequency of operation in a wideband phased array that uses a center frequency-based beamformer. This effect called misfocus, reduces the effective operating bandwidth of the near field system. To mitigate the misfocus effect, we propose a technique called InFocus that constructs beams which are well suited for massive wideband phased arrays. InFocus enables massive wideband phased array-based radios to achieve a higher data rate than comparable beamforming solutions