Optimized Resource Allocation for MIMO Multi-carrier Multi-user Communication Systems

Optimized Resource Allocation for MIMO Multi-carrier Multi-user Communication Systems
Author: Chiang-Yu Chen
Publisher:
Total Pages: 121
Release: 2008
Genre:
ISBN: 9780549488934

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Since rate maximization is not always the design objective of system operators, other optimization problems such as power control, proportional rate allocation, and margin maximization, are formulated. Interestingly, after the Lagrange dual decomposition, all the problems have the same tonal subproblem so that the techniques in weighted sum-rate maximization problems can be applied.

Resource Allocation for Max-Min Fairness in Multi-Cell Massive MIMO

Resource Allocation for Max-Min Fairness in Multi-Cell Massive MIMO
Author: Trinh van Chien
Publisher: Linköping University Electronic Press
Total Pages: 36
Release: 2018-01-11
Genre:
ISBN: 917685387X

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Massive MIMO (multiple-input multiple-output) is considered as an heir of the multi-user MIMO technology and it has recently gained lots of attention from both academia and industry. By equipping base stations (BSs) with hundreds of antennas, this new technology can provide very large multiplexing gains by serving many users on the same time-frequency resources and thereby bring significant improvements in spectral efficiency (SE) and energy efficiency (EE) over the current wireless networks. The transmit power, pilot training, and spatial transmission resources need to be allocated properly to the users to achieve the highest possible performance. This is called resource allocation and can be formulated as design utility optimization problems. If the resource allocation in Massive MIMO is optimized, the technology can handle the exponential growth in both wireless data traffic and number of wireless devices, which cannot be done by the current cellular network technology. In this thesis, we focus on two resource allocation aspects in Massive MIMO: The first part of the thesis studies if power control and advanced coordinated multipoint (CoMP) techniques are able to bring substantial gains to multi-cell Massive MIMO systems compared to the systems without using CoMP. More specifically, we consider a network topology with no cell boundary where the BSs can collaborate to serve the users in the considered coverage area. We focus on a downlink (DL) scenario in which each BS transmits different data signals to each user. This scenario does not require phase synchronization between BSs and therefore has the same backhaul requirements as conventional Massive MIMO systems, where each user is preassigned to only one BS. The scenario where all BSs are phase synchronized to send the same data is also included for comparison. We solve a total transmit power minimization problem in order to observe how much power Massive MIMO BSs consume to provide the requested quality of service (QoS) of each user. A max-min fairness optimization is also solved to provide every user with the same maximum QoS regardless of the propagation conditions. The second part of the thesis considers a joint pilot design and uplink (UL) power control problem in multi-cell Massive MIMO. The main motivation for this work is that the pilot assignment and pilot power allocation is momentous in Massive MIMO since the BSs are supposed to construct linear detection and precoding vectors from the channel estimates. Pilot contamination between pilot-sharing users leads to more interference during data transmission. The pilot design is more difficult if the pilot signals are reused frequently in space, as in Massive MIMO, which leads to greater pilot contamination effects. Related works have only studied either the pilot assignment or the pilot power control, but not the joint optimization. Furthermore, the pilot assignment is usually formulated as a combinatorial problem leading to prohibitive computational complexity. Therefore, in the second part of this thesis, a new pilot design is proposed to overcome such challenges by treating the pilot signals as continuous optimization variables. We use those pilot signals to solve different max-min fairness optimization problems with either ideal hardware or hardware impairments.

Resource Allocation in Multiuser Multicarrier Wireless Systems

Resource Allocation in Multiuser Multicarrier Wireless Systems
Author: Ian C. Wong
Publisher: Springer Science & Business Media
Total Pages: 126
Release: 2007-11-15
Genre: Technology & Engineering
ISBN: 0387749454

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This book proposes a unified algorithmic framework based on dual optimization techniques that have complexities that are linear in the number of subcarriers and users, and that achieve negligible optimality gaps in standards-based numerical simulations. Adaptive algorithms based on stochastic approximation techniques are also proposed, which are shown to achieve similar performance with even much lower complexity. All the algorithms proposed are clearly presented in concise block diagrams allowing the reader to implement these algorithms in the software of their choice. This book is an accessible reference for researchers and industry practitioners alike.

Resource Allocation for OFDMA Systems

Resource Allocation for OFDMA Systems
Author: Chen Chen
Publisher: Springer
Total Pages: 132
Release: 2019-06-29
Genre: Technology & Engineering
ISBN: 3030193926

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This book introduces the sources and historic collection campaigns of resource allocation in wireless communication systems. The unique characteristics of MIMO-OFDMA systems are thoroughly studied and summarized. Remarks on resource allocation and spectrum sharing are also presented, which demonstrate the great value of resource allocation techniques, but also introduce distinct challenges of resource allocation in MIMO-OFDMA systems. Novel resource allocation techniques for OFDMA Systems are surveyed from various applications (e.g., for unicast, or multicast with Guaranteed BER and Rate, subcarrier and power allocation with various detectors, low-complexity energyefficient resource allocation, etc.) in this book. Due to the high mobility and low latency requirements of 5G wireless communications, this book discusses how to deal with the imperfect CSI. It also discusses how to deal with e.g., throughput maximization, outage probabilities maximization and guarantee, energy efficiency, physical-layer security issues with feedback channel capacity constraints, in order to characterize and understand the applications of practical scenes. This book will target professionals & researchers working in the fields of Wireless Communications and Networking, Resource Allocation and Transmissions. Advanced-level students in electrical engineering and computer science will also find this book useful as a secondary textbook.

Optimal Resource Allocation in Coordinated Multi-Cell Systems

Optimal Resource Allocation in Coordinated Multi-Cell Systems
Author: Emil Björnson
Publisher: Now Pub
Total Pages: 282
Release: 2013
Genre: Technology & Engineering
ISBN: 9781601986382

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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.

Resource Allocation and MIMO for 4G and Beyond

Resource Allocation and MIMO for 4G and Beyond
Author: Francisco Rodrigo Porto Cavalcanti
Publisher: Springer Science & Business Media
Total Pages: 557
Release: 2013-10-23
Genre: Technology & Engineering
ISBN: 1461480574

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This book will be a comprehensive collection of advanced concepts related to 4th generation wireless communication systems. It will be divided into two main parts: resource allocation and transceiver architectures. These two research areas are at the core of the recent advances experimented by wireless communication systems. Each chapter will cover a relevant, timely, topic with two focuses: a first part which is of tutorial and survey nature, reviews the state of the art in that topic, followed by a more deep treatment including current research topics, case studies and performance analysis.

Single- And Multi-Carrier Mimo Transmission for Broadband Wireless Systems

Single- And Multi-Carrier Mimo Transmission for Broadband Wireless Systems
Author: Ramjee Prasad
Publisher: CRC Press
Total Pages: 383
Release: 2022-09-01
Genre: Technology & Engineering
ISBN: 1000791173

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The main focus of Single- and Multi-Carrier MIMO Transmission for Broadband Wireless Systems is to provide the basic understanding of the underlying techniques related to PHY-MAC design of future wireless systems. It includes basic concepts related to single- and multi-carrier transmissions together with MIMO techniques. Discussions related to different recent standards that use single- and multi-carrier transmissions are also explained.Single- and Multi-Carrier MIMO Transmission for Broadband Wireless Systems provides a comprehensive and holistic approach to the variety of technical solutions. Future system design would require these different technologies to work together, and not independently. Therefore, it is very important to analyze the effects and gains when they are put together in a unified platform. This is the prime focus of this book. Moreover, the authors include recent research results which are not yet published in another form. The book is intended to be used for lectures in graduate level courses at universities. PhD level students should also find it useful as this book will outline the fundamental concepts and design methods for PHY and MAC layers of future wireless systems. This book can also be used as a reference by engineers and developers in the industry as well as by researchers in academia. For professionals, system architects and managers who play a key role in the selection of a baseline system concept for future wireless standards, such as IMT-Advanced type architecture, the authors will include discussions, analysis and guidelines to highlight overall system level perspective.

Optimizing Massive MIMO

Optimizing Massive MIMO
Author: Hei Victor Cheng
Publisher: Linköping University Electronic Press
Total Pages: 63
Release: 2018-04-11
Genre:
ISBN: 9176853276

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The past decades have seen a rapid growth of mobile data traffic,both in terms of connected devices and data rate. To satisfy the evergrowing data traffic demand in wireless communication systems, thecurrent cellular systems have to be redesigned to increase both spectralefficiency and energy efficiency. Massive MIMO(Multiple-Input-Multiple-Output) is one solution that satisfy bothrequirements. In massive MIMO systems, hundreds of antennas areemployed at the base station to provide service to many users at thesame time and frequency. This enables the system to serve the userswith uniformly good quality of service simultaneously, with low-costhardware and without using extra bandwidth and energy. To achievethis, proper resource allocation is needed. Among the availableresources, transmit power beamforming are the most important degrees offreedom to control the spectral efficiency and energy efficiency. Dueto the use of excessive number of antennas and low-end hardware at thebase station, new aspects of power allocation and beamforming compared to currentsystems arises. In the first part of the thesis, new uplink power allocation schemes that based on long term channel statistics isproposed. Since quality of the channel estimates is crucial in massive MIMO, in addition to data power allocation, joint power allocationthat includes the pilot power as additional variable should be considered. Therefore a new framework for power allocation thatmatches practical systems is developed, as the methods developed in the literature cannot be applied directly to massive MIMO systems. Simulation results confirm the advantages brought by the the proposed new framework. In the second part, we introduces a new approach to solve the joint precoding and power allocation for different objective in downlink scenarios by a combination of random matrix theory and optimization theory. The new approach results in a simplified problem that, though non-convex, obeys a simple separable structure. Simulation results showed that the proposed scheme provides large gains over heuristic solutions when the number of users in the cell is large, which is suitable for applying in massive MIMO systems. In the third part we investigate the effects of using low-end amplifiers at the basestations. The non-linear behavior of power consumption in these amplifiers changes the power consumption model at the basestation, thereby changes the power allocation and beamforming design. Different scenarios are investigated and resultsshow that a certain number of antennas can be turned off in some scenarios. In the last part we consider the use of non-orthogonal-multiple-access (NOMA) inside massive MIMO systems in practical scenarios where channel state information (CSI) is acquired through pilot signaling. Achievable rate analysis is carried out for different pilot signaling schemes including both uplink and downlink pilots. Numerical results show that when downlink CSI is available at the users, our proposed NOMA scheme outperforms orthogonal schemes. However with more groups of users present in the cell, it is preferable to use multi-user beamforming in stead of NOMA.

Computationally Efficient Algorithms for Resource Allocation in Cognitive Radio and Green Communication Systems

Computationally Efficient Algorithms for Resource Allocation in Cognitive Radio and Green Communication Systems
Author: Muhammad Naeem
Publisher:
Total Pages: 332
Release: 2011
Genre: Cognitive radio networks
ISBN:

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Cognitive radio is an interesting concept for solving the problem of spectrum availability by allowing non-licensed users to exploit underutilized licensed frequency bands. We note that a combination of the cognitive radio with cooperative communication and/or MIMO technology can possibly enhance the system performance significantly. In this research, a number of resource allocation problems are examined for cognitive radio systems (CRS) that have relaying and/or MIMO capabilities, and computationally efficient resource allocation schemes are proposed. The general objective is to devise resource allocation schemes in the cognitive radio that maximize the resource utilization under the constraint of acceptable interference to the primary (licensed) users. In particular, in this thesis we present efficient schemes for jointly deciding the assignment of multiple relays to users and their power levels. Fairness is also considered in assigning multiple relays to multiple secondary users. We also propose low-complexity distributed schemes for joint subcarrier and relay assignment in cooperative multi-carrier multi-cast CRS. Another class of resource allocation problems addressed this thesis regards selecting and scheduling users in multiuser systems. In multiuser cognitive MIMO systems, user selection and scheduling significantly affects the system performance. This thesis addresses joint user scheduling and power allocation in the CRS equipped with multiple antennas. Optimization of such user scheduling and power allocation has combinatorial aspects, and the exhaustive search for an exactly optimal solution is impractical due to its computational complexity. This thesis presents low-complexity suboptimal algorithms to maximize the sum-rate capacity of the uplink communication in cognitive MIMO systems under the constraint that the interference to the primary users is below a specified level.

Resource Allocation in Multiuser Multicarrier Wireless Systems

Resource Allocation in Multiuser Multicarrier Wireless Systems
Author: Ian C. Wong
Publisher: Springer
Total Pages: 0
Release: 2008-11-01
Genre: Technology & Engineering
ISBN: 9780387521176

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This book proposes a unified algorithmic framework based on dual optimization techniques that have complexities that are linear in the number of subcarriers and users, and that achieve negligible optimality gaps in standards-based numerical simulations. Adaptive algorithms based on stochastic approximation techniques are also proposed, which are shown to achieve similar performance with even much lower complexity. All the algorithms proposed are clearly presented in concise block diagrams allowing the reader to implement these algorithms in the software of their choice. This book is an accessible reference for researchers and industry practitioners alike.