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Book Wireless Coordinated Multicell Systems

Download or read book Wireless Coordinated Multicell Systems written by Duy H. N. Nguyen and published by Springer. This book was released on 2014-05-15 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: This SpringerBrief discusses the current research on coordinated multipoint transmission/reception (CoMP) in wireless multi-cell systems. This book analyzes the structure of the CoMP precoders and the message exchange mechanism in the CoMP system in order to reveal the advantage of CoMP. Topics include interference management in wireless cellular networks, joint signal processing, interference coordination, uplink and downlink precoding and system models. After an exploration of the motivations and concepts of CoMP, the authors present the architectures of a CoMP system. Practical implementation and operational challenges of CoMP are discussed in detail. Also included is a review of CoMP architectures and deployment scenarios in the LTE-Advanced standard. Readers are exposed to the latest multiuser precoding designs for the CoMP system under two operating modes, interference aware and interference coordination. Wireless Coordinated Multi cell Systems: Architectures and Precoding Designs is a concise and approachable tool for researchers, professionals and advanced-level students interested in wireless communications and networks.

Book Optimal Resource Allocation in Coordinated Multi cell Systems

Download or read book Optimal Resource Allocation in Coordinated Multi cell Systems written by Emil Björnson and published by . This book was released on 2013 with total page 269 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of multiple antennas at base stations is a key component in the design of cellular communication systems that can meet high-capacity demands in the downlink. Under ideal conditions, the gain of employing multiple antennas is well-recognized : the data throughput increases linearly with the number of transmit antennas if the spatial dimension is utilized to serve many users in parallel. The practical performance of multi-cell systems is, however, limited by a variety of nonidealities, such as insufficient channel knowledge, high computational complexity, heterogeneous user conditions, limited backhaul capacity, transceiver impairments, and the constrained level of coordination between base stations.

Book Coordinated Multi Point in Mobile Communications

Download or read book Coordinated Multi Point in Mobile Communications written by Patrick Marsch and published by Cambridge University Press. This book was released on 2011-07-21 with total page 507 pages. Available in PDF, EPUB and Kindle. Book excerpt: A self-contained guide to coordinated multi-point (CoMP), this comprehensive book covers everything from theoretical basics to practical implementation. Addressing a wide range of topics, it highlights the potential gains of CoMP, the fundamental degrees of freedom involved and the key challenges of using CoMP in practice. The editors and contributors bring unique real-world experience from running the world's first and largest test beds for LTE-Advanced, and recent field trial results from these tests are presented. With detailed insight into the realistic potential of CoMP as a key technology for LTE-Advanced and beyond, this is a must-read resource for professionals and students who want the big picture on CoMP or require in-depth knowledge of how to build cellular communication systems for the future.

Book Optimal Resource Allocation in Coordinated Multi Cell Systems

Download or read book Optimal Resource Allocation in Coordinated Multi Cell Systems written by Emil Björnson and published by Now Pub. This book was released on 2013 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optimal Resource Allocation in Coordinated Multi-Cell Systems provides a solid grounding and understanding for optimization of practical multi-cell systems and will be of interest to all researchers and engineers working on the practical design of such systems.

Book Enhanced Multi cell Coordination in Wireless Communication System Using Beamforming Methods

Download or read book Enhanced Multi cell Coordination in Wireless Communication System Using Beamforming Methods written by Omar Khaldoon Abdulrahman and published by . This book was released on 2016 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objectives of this work are as follows to modify and develop new mathematical models of the MVDR algorithm to increase the robustness of MVDR beamformer against steering vector errors caused by calibration or manufacturing errors, and increase the estimation and beamforming accuracy using the actual data mode subjected to double constraints; to design a novel CoMP architecture through innovative division of an LTE cell into three spatial regions, where different scheduling methods (AJN, SCBF, and Non-CoMP) can run in parallel, thus dramatically increasing the capacity of the system; to incorporate MVDR beamformer into CoMP architecture in order to generate accurate beamforming weight within each base station, resulting in reducing signalling overhead among the LTE base stations.

Book Multicell Coordination with Multiple Receive Antennas

Download or read book Multicell Coordination with Multiple Receive Antennas written by Insoo Hwang and published by . This book was released on 2013 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: In multicell coordinated networks where multiple base stations cooperate to jointly combat interference from adjacent cells and fading to receivers, one of the outstanding questions is what is the role of receive antenna and receiver processing. Multiple receive antennas not only enable additional degrees of freedom at each receiver to combat the other-cell interference but also can change the transmitter design because transmitter and receiver beamforming design is often closely coordinated. In this dissertation, we investigate the role of the multiple receive antennas in multicell cooperative systems under different interference conditions. We then present novel non-iterative and iterative coordinated beamforming and precoding algorithms with different receiver processing. We present comprehensive performance comparison of various multicell cooperative systems and explore the feasibility of achieving much higher throughput via hyper-densification of heterogeneous and small cell networks with mandatory multicell cooperation.

Book 5G Mobile and Wireless Communications Technology

Download or read book 5G Mobile and Wireless Communications Technology written by Afif Osseiran and published by Cambridge University Press. This book was released on 2016-06-02 with total page 439 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive overview of the 5G landscape covering technology options, most likely use cases and potential system architectures.

Book Communications  Signal Processing  and Systems

Download or read book Communications Signal Processing and Systems written by Qilian Liang and published by Springer. This book was released on 2019-05-04 with total page 1125 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book brings together papers from the 2018 International Conference on Communications, Signal Processing, and Systems, which was held in Dalian, China on July 14–16, 2018. Presenting the latest developments and discussing the interactions and links between these multidisciplinary fields, the book spans topics ranging from communications, signal processing and systems. It is aimed at undergraduate and graduate electrical engineering, computer science and mathematics students, researchers and engineers from academia and industry as well as government employees.

Book Cooperative Cellular Wireless Networks

Download or read book Cooperative Cellular Wireless Networks written by Ekram Hossain and published by Cambridge University Press. This book was released on 2011-03-10 with total page 545 pages. Available in PDF, EPUB and Kindle. Book excerpt: A self-contained guide to the state-of-the-art in cooperative communications and networking techniques for next generation cellular wireless systems, this comprehensive book provides a succinct understanding of the theory, fundamentals and techniques involved in achieving efficient cooperative wireless communications in cellular wireless networks. It consolidates the essential information, addressing both theoretical and practical aspects of cooperative communications and networking in the context of cellular design. This one-stop resource covers the basics of cooperative communications techniques for cellular systems, advanced transceiver design, relay-based cellular networks, and game-theoretic and micro-economic models for protocol design in cooperative cellular wireless networks. Details of ongoing standardization activities are also included. With contributions from experts in the field divided into five distinct sections, this easy-to-follow book delivers the background needed to develop and implement cooperative mechanisms for cellular wireless networks.

Book MIMO Wireless Networks

Download or read book MIMO Wireless Networks written by Bruno Clerckx and published by Academic Press. This book was released on 2013-01-23 with total page 773 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is unique in presenting channels, techniques and standards for the next generation of MIMO wireless networks. Through a unified framework, it emphasizes how propagation mechanisms impact the system performance under realistic power constraints. Combining a solid mathematical analysis with a physical and intuitive approach to space-time signal processing, the book progressively derives innovative designs for space-time coding and precoding as well as multi-user and multi-cell techniques, taking into consideration that MIMO channels are often far from ideal.Reflecting developments since the first edition was published, this book has been thoroughly revised, and now includes new sections and five new chapters, respectively dealing with receiver design, multi-user MIMO, multi-cell MIMO, MIMO implementation in standards, and MIMO system-level evaluation. - Extended introduction to multi-dimensional propagation, including polarization aspects - Detailed and comparative description of physical models and analytical representations of single- and multi-link MIMO channels, covering the latest standardized models - Thorough overview of space-time coding techniques, covering both classical and more recent schemes under information theory and error probability perspectives - Intuitive illustration of how real-world propagation affects the capacity and the error performance of MIMO transmission schemes - Detailed information theoretic analysis of multiple access, broadcast and interference channels - In-depth presentation of multi-user diversity, resource allocation and (non-)linear MU-MIMO precoding techniques with perfect and imperfect channel knowledge - Extensive coverage of cooperative multi-cell MIMO-OFDMA networks, including network resource allocation optimization, coordinated scheduling, beamforming and power control, interference alignment, joint processing, massive and network MIMO - Applications of MIMO and Coordinated Multi-Point (CoMP) in LTE, LTE-A and WiMAX - Theoretical derivations and results contrasted with practical system level evaluations highlighting the performance of single- and multi-cell MIMO techniques in realistic deployments

Book Green Radio Communication Networks

Download or read book Green Radio Communication Networks written by Ekram Hossain and published by Cambridge University Press. This book was released on 2012-07-05 with total page 439 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents state-of-the-art research on green radio communications and networking technology to researchers and professionals working in wireless communication.

Book Resource Allocation with Multi cell Coordination in Wireless Networks

Download or read book Resource Allocation with Multi cell Coordination in Wireless Networks written by Binglai Niu and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Mobile and Wireless Communications for IMT Advanced and Beyond

Download or read book Mobile and Wireless Communications for IMT Advanced and Beyond written by Afif Osseiran and published by John Wiley & Sons. This book was released on 2011-08-08 with total page 325 pages. Available in PDF, EPUB and Kindle. Book excerpt: A timely addition to the understanding of IMT-Advanced, this book places particular emphasis on the new areas which IMT-Advanced technologies rely on compared with their predecessors. These latest areas include Radio Resource Management, Carrier Aggregation, improved MIMO support and Relaying. Each technique is thoroughly described and illustrated before being surveyed in context of the LTE-Advanced standards. The book also presents state-of-the-art information on the different aspects of the work of standardization bodies (such as 3GPP and IEEE), making global links between them. Explores the latest research innovations to assess the future of the LTE standard Covers the latest research techniques for beyond IMT-Advanced such as Coordinated multi-point systems (CoMP), Network Coding, Device-to-Device and Spectrum Sharing Contains key information for researchers from academia and industry, engineers, regulators and decision makers working on LTE-Advanced and beyond

Book Millimeter Wave Communications in 5G and Towards 6G

Download or read book Millimeter Wave Communications in 5G and Towards 6G written by Vasanthan Raghavan and published by CRC Press. This book was released on 2024-11-20 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explores different facets of millimeter wave systems, which form a central part of 5G systems. It explains how these systems serve as a foundational building block of 5G-Advanced/6G as these systems evolve. Millimeter Wave Communications in 5G and Towards 6G focuses on millimeter wave channel modeling, radio frequency (RF) and antenna level constraints imposed on beamforming, beamforming design for link level incorporating the RF/antenna constraints and the channel structure, as well as system level deployment considerations. With significant academic and industrial experience, the authors are well-equipped in explaining how the millimeter wave research developed, the fundamental principles/math beneath the technology, and in explaining precisely the “Why?” behind the “What?” that make the 5G-NR specifications. The authors examine point-to-point systems at a single link level and show how the traditional sub-6 GHz-based beamforming procedures simplify to a simplistic signal processing approach of directional beam scanning. This book examines the foundational background that led to specific choices in the millimeter wave part of the 5G-NR spec as well as chart out the roadmap in terms of future research and development activities in this arena. The book ends by providing a scope of future research in this area. This book is geared towards both introductory as well as advanced researchers in both industry and academia working in the areas of 5G, 5G-Advanced and 6G communications. It would also be useful for senior undergraduate and graduate students in universities focusing on wireless communications topics.

Book Cell Free Massive MIMO

    Book Details:
  • Author : Giovanni Interdonato
  • Publisher : Linköping University Electronic Press
  • Release : 2020-09-09
  • ISBN : 9179298087
  • Pages : 75 pages

Download or read book Cell Free Massive MIMO written by Giovanni Interdonato and published by Linköping University Electronic Press. This book was released on 2020-09-09 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fifth generation of mobile communication systems (5G) is nowadays a reality. 5G networks are been deployed all over the world, and the first 5G-capable devices (e.g., smartphones, tablets, wearable, etc.) are already commercially available. 5G systems provide unprecedented levels of connectivity and quality of service (QoS) to cope with the incessant growth in the number of connected devices and the huge increase in data-rate demand. Massive MIMO (multiple-input multiple-output) technology plays a key role in 5G systems. The underlying principle of this technology is the use of a large number of co-located antennas at the base station, which coherently transmit/receive signals to/from multiple users. This signal co-processing at multiple antennas leads to manifold benefits: array gain, spatial diversity and spatial user multiplexing. These elements enable to meet the QoS requirements established for the 5G systems. The major bottleneck of massive MIMO systems as well as of any cellular network is the inter-cell interference, which affects significantly the cell-edge users, whose performance is already degraded by the path attenuation. To overcome these limitations and provide uniformly excellent service to all the users we need a more radical approach: we need to challenge the cellular paradigm. In this regard, cell-free massive MIMO constitutes the paradigm shift. In the cell-free paradigm, it is not the base station surrounded by the users, but rather it is each user being surrounded by smaller, simpler, serving base stations referred to as access points (APs). In such a system, each user experiences being in the cell-center, and it does not experience any cell boundaries. Hence, the terminology cell-free. As a result, users are not affected by inter-cell interference, and the path attenuation is significantly reduced due to the presence of many APs in their proximity. This leads to impressive performance. Although appealing from the performance viewpoint, the designing and implementation of such a distributed massive MIMO system is a challenging task, and it is the object of this thesis. More specifically, in this thesis we study: Paper A) The large potential of this promising technology in realistic indoor/outdoor scenarios while also addressing practical deployment issues, such as clock synchronization among APs, and cost-efficient implementations. We provide an extensive description of a cell-free massive MIMO system, emphasizing strengths and weaknesses, and pointing out differences and similarities with existing distributed multiple antenna systems, such as Coordinated MultiPoint (CoMP). Paper B) How to preserve the scalability of the system, by proposing a solution related to data processing, network topology and power control. We consider a realistic scenario where multiple central processing units serve disjoint subsets of APs, and compare the spectral efficiency provided by the proposed scalable framework with the canonical cell-free massive MIMO and CoMP. Paper C) How to improve the spectral efficiency (SE) in the downlink (DL), by devising two distributed precoding schemes, referred to as local partial zero-forcing (ZF) and local protective partial ZF, that provide an adaptable trade-off between interference cancelation and boosting of the desired signal, with no additional front-haul overhead, and that are implementable by APs with very few antennas. We derive closed-form expressions for the achievable SE under the assumption of independent Rayleigh fading channel, channel estimation error and pilot contamination. These closed-form expressions are then used to devise optimal max-min fairness power control. Paper D) How to further improve the SE by letting the user estimate the DL channel from DL pilots, instead of relying solely on the knowledge of the channel statistics. We derive an approximate closed-form expression of the DL SE for conjugate beamforming (CB), and assuming independent Rayleigh fading. This expression accounts for beamformed DL pilots, estimation errors and pilot contamination at both the AP and the user side. We devise a sequential convex approximation algorithm to globally solve the max-min fairness power control optimization problem, and a greedy algorithm for uplink (UL) and DL pilot assignment. The latter consists in jointly selecting the UL and DL pilot pair, for each user, that maximizes the smallest SE in the network. Paper E) A precoding scheme that is more suitable when only the channel statistics are available at the users, referred to as enhanced normalized CB. It consists in normalizing the precoding vector by its squared norm in order to reduce the fluctuations of the effective channel seen at the user, and thereby to boost the channel hardening. The performance achieved by this scheme is compared with the CB scheme with DL training (described in Paper D). Paper F) A maximum-likelihood-based method to estimate the channel statistics in the UL, along with an accompanying pilot transmission scheme, that is particularly useful in line-of-sight operation and in scenarios with resource constraints. Pilots are structurally phase-rotated over different coherence blocks to create an effective statistical distribution of the received pilot signal that can be efficiently exploited by the AP when performing the proposed estimation method. The overall conclusion is that cell-free massive MIMO is not a utopia, and a practical, distributed, scalable, high-performance system can be implemented. Today it represents a hot research topic, but tomorrow it might represent a key enabler for beyond-5G technology, as massive MIMO has been for 5G. La quinta generazione dei sistemi radiomobili cellulari (5G) è oggi una realtà. Le reti 5G si stanno diffondendo in tutto il mondo e i dispositivi 5G (ad esempio smartphones, tablets, indossabili, ecc.) sono già disponibili sul mercato. I sistemi 5G garantiscono livelli di connettività e di qualità di servizio senza precedenti, per fronteggiare l’incessante crescita del numero di dispositivi connessi alla rete e della domanda di dati ad alta velocità. La tecnologia Massive MIMO (multiple-input multiple-output) riveste un ruolo fondamentale nei sistemi 5G. Il principio alla base di questa tecnologia è l’impiego di un elevato numero di antenne collocate nella base station (stazione radio base) le quali trasmettono/ricevono segnali, in maniere coerente, a/da più terminali utente. Questo co-processamento del segnale da parte di più antenne apporta molteplici benefici: guadagno di array, diversità spaziale e multiplazione degli utenti nel dominio spaziale. Questi elementi consentono di raggiungere i requisiti di servizio stabiliti per i sistemi 5G. Tuttavia, il limite principale dei sistemi massive MIMO, così come di ogni rete cellulare, è rappresentato dalla interferenza inter-cella (ovvero l’interferenza tra aree di copertura gestite da diverse base stations), la quale riduce in modo significativo le performance degli utenti a bordo cella, già degradate dalle attenuazioni del segnale dovute alla considerevole distanza dalla base station. Per superare queste limitazioni e fornire una qualità del servizio uniformemente eccellente a tutti gli utenti, è necessario un approccio più radicale e guardare oltre il classico paradigma cellulare che caratterizza le attuali architetture di rete. A tal proposito, cell-free massive MIMO (massive MIMO senza celle) costituisce un cambio di paradigma: ogni utente è circondato e servito contemporaneamente da numerose, semplici e di dimensioni ridotte base stations, denominate access points (punti di accesso alla rete). Gli access points cooperano per servire tutti gli utenti nella loro area di copertura congiunta, eliminando l’interferenza inter-cella e il concetto stesso di cella. Non risentendo più dell’effetto “bordo-cella”, gli utenti possono usufruire di qualità di servizio e velocità dati eccellenti. Sebbene attraente dal punto di vista delle performance, l’implementazione di un tale sistema distribuito è una operazione impegnativa ed è oggetto di questa tesi. Piu specificatamente, questa tesi di dottorato tratta: Articolo A) L’enorme potenziale di questa promettente tecnologia in scenari realistici sia indoor che outdoor, proponendo anche delle soluzioni di implementazione flessibili ed a basso costo. Articolo B) Come preservare la scalabilità del sistema, proponendo soluzioni distribuite riguardanti il processamento e la condivisione dei dati, l’architettura di rete e l’allocazione di potenza, ovvero come ottimizzare i livelli di potenza trasmessa dagli access points per ridurre l’interferenza tra utenti e migliorare le performance. Articolo C) Come migliorare l’efficienza spettrale in downlink (da access point verso utente) proponendo due schemi di pre-codifica dei dati di trasmissione, denominati local partial zero-forcing (ZF) e local protective partial ZF, che forniscono un perfetto compromesso tra cancellazione dell’interferenza tra utenti ed amplificazione del segnale desiderato. Articolo D) Come migliorare l’efficienza spettrale in downlink permettendo al terminale utente di stimare le informazioni sulle condizioni istantanee del canale da sequenze pilota, piuttosto che basarsi su informazioni statistiche ed a lungo termine, come convenzionalmente previsto. Articolo E) In alternativa alla soluzione precedente, uno schema di pre-codifica che è più adatto al caso in cui gli utenti hanno a disposizione esclusivamente informazioni statistiche sul canale per poter effettuare la decodifica dei dati. Articolo F) Un metodo per permettere agli access points di stimare, in maniera rapida, le condizioni di canale su base statistica, favorito da uno schema di trasmissione delle sequenze pilota basato su rotazione di fase. Realizzare un sistema cell-free massive MIMO pratico, distribuito, scalabile e performante non è una utopia. Oggi questo concept rappresenta un argomento di ricerca interessante, attraente e stimolante ma in futuro potrebbe costituire un fattore chiave per le tecnologie post-5G, proprio come massive MIMO lo è stato per il 5G. Den femte generationens mobilkommunikationssystem (5G) är numera en verklighet. 5G-nätverk är utplacerade på ett flertal platser världen över och de första 5G-kapabla terminalerna (såsom smarta telefoner, surfplattor, kroppsburna apparater, etc.) är redan kommersiellt tillgängliga. 5G-systemen kan tillhandahålla tidigare oöverträffade nivåer av uppkoppling och servicekvalitet och är designade för en fortsatt oavbruten tillväxt i antalet uppkopplade apparater och ökande datataktskrav. Massiv MIMO-teknologi (eng: multiple-input multiple-output) spelar en nyckelroll i dagens 5G-system. Principen bakom denna teknik är användningen av ett stort antal samlokaliserade antenner vid basstationen, där alla antennerna sänder och tar emot signaler faskoherent till och från flera användare. Gemensam signalbehandling av många antennsignaler ger ett flertal fördelar, såsom hög riktverkan via lobformning, vilket leder till högre datatakter samt möjliggör att flera användare utnyttjar samma radioresurser via rumslig användarmultiplexering. Eftersom en signal kan gå genom flera olika, möjligen oberoende kanaler, så utsätts den för flera olika förändringar samtidigt. Denna mångfald ökar kvaliteten på signalen vid mottagaren och förbättrar radiolänkens robusthet och tillförlitlighet. Detta gör det möjligt att uppfylla de höga kraven på servicekvalitet som fastställts för 5G-systemen. Den största begränsningen för massiva MIMO-system såväl som för alla cellulära mobilnätverk, är störningar från andra celler som påverkar användare på cellkanten väsentligt, vars prestanda redan begränsas av sträckdämpningen på radiokanalen. För att övervinna dessa begränsningar och för att kunna tillhandahålla samma utmärkta servicekvalitet till alla användare behöver vi ett mer radikalt angreppssätt: vi måste utmana cellparadigmet. I detta avseende utgör cellfri massiv-MIMO teknik ett paradigmskifte. I cellfri massive-MIMO är utgångspunkten inte att basstationen är omgiven av användare som den betjänar, utan snarare att varje användare omges av basstationer som de betjänas av. Dessa basstationer, ofta mindre och enklare, kallas accesspunkter (AP). I ett sådant system upplever varje användare att den befinner sig i centrum av systemet och ingen användare upplever några cellgränser. Därav terminologin cellfri. Som ett resultat av detta påverkas inte användarna av inter-cellstörningar och sträckdämpningen reduceras kraftigt på grund av närvaron av många accesspunkter i varje användares närhet. Detta leder till imponerande prestanda. Även om det är tilltalande ur ett prestandaperspektiv så är utformningen och implementeringen av ett sådant distribuerat massivt MIMO-system en utmanande uppgift, och det är syftet med denna avhandling att studera detta. Mer specifikt studerar vi i denna avhandling: A) den mycket stora potentialen med denna teknik i realistiska inomhus- såväl som utomhusscenarier, samt hur man hanterar praktiska implementeringsproblem, såsom klocksynkronisering bland accesspunkter och kostnadseffektiva implementeringar; B) hur man ska uppnå skalbarhet i systemet genom att föreslå lösningar relaterade till databehandling, nätverkstopologi och effektkontroll; C) hur man ökar datahastigheten i nedlänken med hjälp av två nyutvecklade distribuerade överföringsmetoder som tillhandahåller en avvägning mellan störningsundertryckning och förstärkning av önskade signaler, utan att öka mängden intern signalering till de distribuerade accesspunkterna, och som kan implementeras i accesspunkter med mycket få antenner; D) hur man kan förbättra prestandan ytterligare genom att låta användaren estimera nedlänkskanalen med hjälp av nedlänkspiloter, istället för att bara förlita sig på kunskap om kanalstatistik; E) en överföringsmetod för nedlänk som är mer lämpligt när endast kanalstatistiken är tillgänglig för användarna. Prestandan som uppnås genom detta schema jämförs med en utökad variant av den nedlänk-pilotbaserade metoden (beskrivet i föregående punkt); F) en metod för att uppskatta kanalstatistiken i upplänken, samt en åtföljande pilotsändningsmetod, som är särskilt användbart vid direktvägsutbredning (line-of-sight) och i scenarier med resursbegränsningar. Den övergripande slutsatsen är att cellfri massiv MIMO inte är en utopi, och att ett distribuerat, skalbart, samt högpresterande system kan implementeras praktiskt. Idag representerar detta ett hett forskningsämne, men snart kan det visa sig vara en viktig möjliggörare för teknik bortom dagens system, på samma sätt som centraliserad massiv MIMO har varit för de nya 5G-systemen.

Book Resource Allocation in Uplink OFDMA Wireless Systems

Download or read book Resource Allocation in Uplink OFDMA Wireless Systems written by Elias Yaacoub and published by John Wiley & Sons. This book was released on 2012-02-10 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tackling problems from the least complicated to the most, Resource Allocation in Uplink OFDMA Wireless Systems provides readers with a comprehensive look at resource allocation and scheduling techniques (for both single and multi-cell deployments) in uplink OFDMA wireless networks relying on convex optimization and game theory to thoroughly analyze performance. Inside, readers will find topics and discussions on: Formulating and solving the uplink ergodic sum-rate maximization problem Proposing suboptimal algorithms that achieve a close performance to the optimal case at a considerably reduced complexity and lead to fairness when the appropriate utility is used Investigating the performance and extensions of the proposed suboptimal algorithms in a distributed base station scenario Studying distributed resource allocation where users take part in the scheduling process, and considering scenarios with and without user collaboration Formulating the sum-rate maximization problem in a multi-cell scenario, and proposing efficient centralized and distributed algorithms for intercell interference mitigation Discussing the applicability of the proposed techniques to state-of-the-art wireless technologies, LTE and WiMAX, and proposing relevant extensions Along with schematics and figures featuring simulation results, Resource Allocation in Uplink OFDMA Wireless Systems is a valuable book for?wireless communications and cellular systems professionals and students.

Book Spatial Multidimensional Cooperative Transmission Theories And Key Technologies

Download or read book Spatial Multidimensional Cooperative Transmission Theories And Key Technologies written by Lin Bai and published by World Scientific. This book was released on 2020-08-24 with total page 471 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces the basic theory and key technologies of MIMO multi-antenna system, the characteristics and applications of spatial multi-dimensional cooperative transmission in the Ground-based, Air-based and Space-based communication systems as well as several advanced technologies for spatial multidimensional cooperative transmission from theoretical and practical perspectives. The Chinese edition of this book won the 4th Chinese Government Award for Publishing, and the authors are well known in the field of Spatial Information Network.