Multiple-input multiple-output (MIMO) techniques are the fundamental technology in several standardizations, including long-term evolution (LTE) and LTE-advanced. For instance, MIMO spatial multiplexing (MIMO-SM) is used to increase the system capacity without requiring additional time/frequency resources. However, the performance of the MIMO-SM depends on the employed detection algorithm. Also, multi-user MIMO precoding at the transmitter part is used to support the simultaneous transmission to several users. In this book, we review the basics of MIMO detection. Then, we introduce two detection algorithms, namely, adaptive parallel QRDM algorithm (APQRDM) that increases the detection throughput and adaptive iterative QRD-M algorithm (AIQRDM) that reduces the hardware requirements. Besides, these two algorithms adaptively reduce the computational complexity, while achieving the optimum diversity. Furthermore, in addition to introducing the state of the art of the precoding techniques, we propose a fixed complexity sphere encoder (FSE) that requires a fraction of the computations performed by the QRDM encoder, while achieving a tremendous increase in the precoding throughput.
Multiple input multiple output (MIMO) wireless systems that use multiple transmit and receive antennas allow a gain in reliability (diversity gain) and capacity (multiplexing gain). Unfortunately, these advantages come at the cost of higher computational complexity, particularly when using soft detection (SD). SD features improved performance compared to hard detection and is a prerequisite for iterative receiver structures (turbo receivers). In this thesis we consider the sphere decoder for soft-output MIMO detection and present modifications that allow flexible trade-offs between computational complexity on the one hand and performance and diversity on the other hand. Additionally to these two modifications we present a lower bound on partial sphere decoder metrics that allows to reduce the complexity of the detection using the sphere decoder without performance degradation.
Wireless communication is an emerging field, which has seen enormous growth in the last several years. Wireless Networks and the exponential growth of the internet have resulted in an increased demand for new methods of obtaining robust, high capacity wireless networks. In this book, we have mainly focused on various methods for improving the spectral efficiency and link reliability of Wireless network using MIMO-OFDM system, and also observing the bandwidth efficiency with the varying length of cyclic prefix. We have also focused on different detection algorithms required in the reception of MIMO-OFDM signals, which have recently emerged as a very promising approach to solve detection problem.
MIMO technology promises significant capacity improvements that lead to an efficient use of the radio frequency spectrum. To achieve its anticipated multiplexing gain and meet the requirements for higher data-rate services, existing broadband systems are based on OFDM or similar block-based techniques. These techniques are afflicted by poor design freedom at low redundancy, and are known to suffer badly from co-channel interference (CCI) in the presence of synchronisation errors. Non-block based approaches are scarce and do not require a guard interval; therefore can achieve higher spectral efficiency. The drawbacks of these schemes lie on the large effort in determining the optimum detection order in both space and time. This book, therefore, focuses on non-linear, non-block based precoding and equalisation schemes aiming to achieve higher data throughputs with improved bit error ratio (BER) compared to existing approaches. Furthermore, a rate-optimal computationally-efficient adaptive bit and power loading schemes have been applied considering a greedy algorithm with subchannel grouping concept.
This book includes the PhD research entitled "Experimental consideration of channel capacity using Multiple Input Multiple Output (MIMO) technology". This work was carried out and completed in the Electronics, Telecommunications and Applied Physics Laboratory, in Physics Department at University of Ioannina, in Greece. Fundamental principles and performance aspects of MIMO systems and wireless channel propagation environment are included in the first chapter of the book. In the following chapters, MIMO platform design and implementation aspects are presented and discussed. The basic methodology that are used in a course of experimental measurements on SIMO and MIMO wireless channel propagation in indoor environment as well as the resulted observations are included in chapter 5. The concluding section of the book presents crucial considerations on MIMO wireless communication systems and proposes some improvements that will simplify the measurements on channel characterization
The demand of different multimedia services and different internet supported applications on mobile devices requires a high speed data rate and good service quality. This can be obtained by implementing multiple Antenna technology on both stations i.e. User terminal and base station with an appropriate coding technique, and on the other hand MIMO can fulfill 3G & 4G demand and standard with a combination of other techniques. The MIMO diversity and MIMO multiplexing are the key factors to discuss and matter of concern is to achieve and support high speed data rate. MIMO multiplexing is a way to gain robustness and achievement in speed of data information. The MIMO-OFDM is the reproductive and highly famous services for Wireless broad band access. The combination of MIMO and OFDM accumulates the purpose of each and every scheme that will provide the high throughput. The current and main application of MIMO-OFDM is IEEE 802.16 (WiMAX) which will gain high popularity and the researcher''s attraction for further development and improvement.
MIMO systems using multiple transmitting and receiving antennas are by now well studied. Several axes of these schemes have been explored with the underlying MIMO channel assumed linear. However, when high-power amplifiers (HPA) operating near their peak efficiency operating points are employed in the communication chain, non-linear distortions are introduced in the transmitted signals, and the resulting MIMO channel will be non-linear. This book establishes the concept of Nonlinear MIMO communication channels. The book begins by examining the performance degradations caused by HPA nonlinearities in MIMO channels, using space-time codes and MIMO-beamforming systems as case studies. The book then concludes by highlighting some key HPA nonlinearity compensation techniques suitable for MIMO systems.
We have tried to describe two aspects of MIMO channels: channel capacity and channel modeling. We have analyzed the channel capacity of static and fading MIMO channels when the channel side information is available both at the transmitter and receiver, and when it is available only at the receiver. We have then modeled the MIMO channel in physical and angular domains to understand how it provides spatial multiplexing with the help of degrees of freedom. In physical domain modeling, we have modeled the MIMO channel in terms of individual physical paths. In angular domain modeling, we have described the MIMO channel with respect to fixed spatial basis functions defined by fixed angles that are determined by the spatial resolution of the antenna arrays. All the simulations have been performed on MATLAB 18.104.22.1687 (R2007a).
This book investigates the problem of user selection and scheduling in MIMO-BC. A low-complexity user selection algorithm is proposed when the BS has perfect channel-state information and the performance of the proposed algorithm with linear and non-linear precoding techniques is evaluated. A signalling scheme for the MIMO-BC systems in the absence of perfect CSIT is presented. A novel transmit-antenna selection scheme is proposed. The performance of the proposed scheme with different user selection algorithms and linear receivers is evaluated. The book considers a cross-layer scheduling approach in order to provide QoS guarantees to the users. A scheduling algorithm, multi-user ?-Rule scheduling, is proposed with the capability of maximizing the system throughput and providing QoS to the users. The effect of rate estimation on the performance of the scheduling algorithm is analyzed along with the effect of the variability in the allocated rates on the mean queue lengths of the users. It is shown that by increasing the fairness, the variability in rate allocation decreases, which results in smaller queue sizes for the users with marginal reduction in the sum-capacity of the system.
The aim of this topic is to reduce SER in MIMO System.To investigate a joint diversity scheme and various modulation schemes in a multiple-input multiple-output (MIMO) system. The exact SER of the joint diversity scheme can be derived from M-ary QAM and M-ary PSK modulations in various fading channels. By comparing various fading channels, SER will be reduced and thus performance of SNR in the MIMO systems will be improved.Whenever User increases SER reduced.
Mimo унитаз напольный (2355.6.000.000.1)
This book's main focus is present applications of MIMO OFDM and major aspects like channel Estimation.This book also provides information related to basic channel estimation schemes and also how they can be adapted to MIMO OFDM systems.And finally adaptive scheme was described which utilizes the resources much effective way.In this book i gave matlab implementation of the proposed schemes also and simmulation results areprovided.
In this work, Survey and investigation on inter symbol interference (ISI) and inter carrier interference (ICI) due to either carrier frequency offset or timing offset issues and interference mitigation schemes available, compare and analyze their bit error rate performance to various schemes for OFDM and MIMO-OFDM systems. Efforts have been made to develop an efficient interference cancelling receiver for ISI and ICI, algorithms to be implemented on MATLAB environment for OFDM and MIMO-OFDM which are not available in literature.
The new generation of wireless devices support higher data rates. Most of the new standards like HSPA utilize the spatial multiplexing of MIMO channels to achieve higher data rates, and exploit the diversity of MIMO channels to provide better performance. Hence there is an increased interest in the analysis of MIMO communication systems. The eventual objective is to achieve higher data rates in MIMO systems under the constraints of limited bandwidth and power. The radio spectrum is a scarce resource, and very expensive to license. Hence improved and efficient channel utilization techniques are requisite, that exploit the radio spectrum more proficiently. The multipath characteristics of the environment cause the MIMO channels to be frequency selective. For frequency selective deep fading, MIMO system remains ineffective. OFDM, a multicarrier transmission scheme, is well recognized for its potential for attaining high rate transmission over frequency selective channels. It can transform such a frequency selective MIMO channel into a set of parallel frequency-flat channels. Implementing space resources based on OFDM i.e., MIMO-OFDM provides higher data rate.