George V. Tsoulos

MIMO system technology for wireless communications

SPATIO-TEMPORAL PROPAGATION MODELING G.E. Athanasiadou Introduction Directional Channel Modeling MIMO Propagation Modeling References THEORY AND PRACTICE OF MIMO WIRELESS COMMUNICATION SYSTEMS Dimitra Zarbouti, George Tsoulos, and D. Kaklamani Summary Shannons Capacity Formula Extended Capacity Formula for MIMO Channels Remarks in the Extended Shannon Capacity Formula Capacity of SIMO-MISO Channels Stochastic Channels MIMO Capacity with Rice-Rayleigh Channels Simulations Appendices References INFORMATION THEORY AND ELECTROMAGNETISM: ARE THEY RELATED? Sergey Loyka and Juan Mosig Introduction MIMO Channel Capacity The Laws of Electromagnetism Spatial Capacity and Correlation Spatial Sampling and MIMO Capacity MIMO Capacity of Waveguide Channels Spatial Capacity of Waveguide Channels Acknowledgements References INTRODUCTION TO SPACE-TIME CODING Antonios D. Valkanas and Alexander D. Poularikas Introduction MIMO System and Space-Time Coding Space-Time Block Codes Space-Time Trellis Codes Spatial Multiplexing Space-Time Coding with CSI Knowledge at the Transmitter Other Space-Time Coding Schemes References Acronyms FEEDBACK TECHNIQUES FOR MIMO CHANNELS David J. Love and Robert W. Heath Jr. Feedback Techniques for MIMO Channels References ANTENNA SELECTION IN MIMO SYSTEMS Neelesh Mehta and Andy Molisch Introduction MIMO System Model Spatial Multiplexing Space-Time Codes SIMO Systems Implementing Antenna Selection: Criteria and Algorithms Performance with Non-Idealities Antenna Selection with Spatial Correlation Summary References PERFORMANCE OF MULTI-USER SPATIAL MULTIPLEXING WITH MEASURED CHANNEL DATA Quentin H. Spencer, Jon W. Wallace, Christian B. Peel, Thomas Svantesson, A. Lee Swindlehurst, Harry Lee, and Ajay Gumalla Abstract The Multiple-User MIMO Channel Multi-User MIMO Transmission Schemes Channel Measurements Performance Results Summary Acknowledgements References MULTIUSER MIMO FOR UTRA FDD Jyri Hamalainen, Risto Wichman, Markku Kuusela, Esa Tiirola, and Kari Pajukoski Abstract Introduction UTRA Framework Present Multiantenna Methods in UTRA FDD MIMO in UTRA FDD Uplink MIMO in UTRA FDD Downlink Conclusions and Discussion References MULTIFUNCTIONAL RECONFIGURABLE MICROELECTRO-MECHANICAL SYSTEMS INTEGRATED ANTENNAS FOR MULTIPLE INPUT MULTIPLE OUTPUT SYSTEMS Bedri Artug Cetiner Introduction MRA Concept and Its Links with MIMO Systems RF MEMS Technology Compatible with Microwave Laminates for Fabricating MRAs RF MEMS Integrated Antennas Concluding Remarks References MULTI-ANTENNA TESTBEDS FOR WIRELESS COMMUNICATIONS Raghu Rao, Christian Oberli, Stephan Lang, David Browne, Weijun Zhu, Mike Fitz, and Babak Daneshrad Introduction Testbed Classification Elements of a Successful Testbed Hardware Calibration Field Test Administration Field Test Results References GIGABIT MOBILE COMMUNICATIONS USING REAL-TIME MIMO-OFDM SIGNAL PROCESSING Volker Jungnickel, Andreas Forck, Thomas Haustein, Christoph Juchems, and Wolfgang Zirwas Introduction Implementation Concept A Code-Multiplexed Preamble Channel Estimation Adaptation to the Time-Variant Channel Data Reconstruction Framing, Mapping, Channel Coding, and Real-Time Data Interface Implementation, Complexity, and System Integration Transmission Experiments Conclusions Summary Acknowledgements Appendix 11A References NETWORK PLANNING AND DEPLOYMENT ISSUES FOR MIMO SYSTEMS Thomas Neubauer, Ernst Bonek, and Christoph Mecklenbrauker Network Planning Deployment Smart Antenna Planning Example References INDEX

Estimating MIMO system performance using the correlation matrix approach

The channel capacity of a multiple-input-multiple-output (MIMO) communication system depends substantially on correlation between individual receive branches. We investigate the MIMO capacity using the correlation matrix approach and the Salz-Winters (1994) spatial correlation model. It is shown that for a linear array, correlation has no impact on the MIMO channel capacity provided that the two-element array beamwidth is smaller than the angle spread of the incoming signals. Simple but accurate approximations for the correlation coefficient and the corresponding channel capacity are derived for different angular spreads.

Wireless personal communications for the 21st century: European technological advances in adaptive antennas

Adaptive antennas are now regarded by many within the wireless communications industry as a core system component in future-generation mobile networks. In order to promote European research and development in this strategic area, the Commission of the European Community has funded, through the Research into Advanced Communications in Europe, RACE, and now the Advanced Communications Technologies and Services, ACTS, programs, the Technology in Smart Antennas for Universal Advanced Mobile Infrastructure, TSUNAMI, consortium in order to further technological advances for the next millennium, as reported here.

Adaptive Antennas for Wireless Communications

From the Publisher: In the past decade, the wireless communications community recognized adaptive antennas as a core technology that would help existing systems overcome problems related to spectrum efficiency and provide a vehicle to achieve the ambitious requirements of next-generation networks. The communications industry has already begun to develop adaptive antenna systems for commercial use and at the same time is working with standardization institutes around the world to produce adaptive antenna-friendly standards. Adaptive Antennas for Wireless Communications is a concise, detailed resource of information for all critical issues related to this technology and is compiled from the original published work of experts in the field. The extensive literature covers: Historical and background aspects Radio channel simulation techniques and characteristics Adaptive algorithm performance under a variety of conditions Adaptive antenna performance in different operational environments Design and implementation issues Experimental results Other issues such as network planning and recent novel techniques Adaptive Antennas for Wireless Communications is a valuable reference for helping consultants, researchers, communications professionals, academics, and students gain an in-depth understanding of adaptive antenna technology.

Mobile telemedicine for moving vehicle scenarios: Wireless technology options and challenges

Recent studies conclude that patient survival during a health emergency situation depends on the effective pre-hospital healthcare. Mobile telemedicine exploits different wireless network technologies in order to tackle this problem. This paper looks into the case of mobile telemedicine service provision in a moving vehicle (ambulance). The special characteristics and requirements of this operational scenario are discussed in terms of benefits and limitations in conjunction with the application of existing wireless communication systems in this case. Moreover, emerging wireless broadband communication systems and spectrum access technology are considered in the same context, in an attempt to further improve service provision and face future challenges.

Calibration and linearity issues for an adaptive antenna system

Adaptive antennas are among the favourite techniques to help the current systems evolve towards third generation mobile communication systems. However, among the major concerns for adaptive antenna systems are the calibration process and the non-linearity effects of the RF-IF chains upon the performance of the beamforming network. This article investigates these issues based on experimental results produced with the adaptive antenna testbed that was developed under the RACE TSUNAMI project. Results highlight the sensitivity of the system on both the linearisation and the calibration processes employed.

Low-complexity smart antenna methods for third-generation W-CDMA systems

There is still an open debate within the research community regarding the likely performance enhancement of smart antennas versus their complexity for commercial wireless applications. The goal of the study presented in this paper is to investigate the performance improvement attainable using relatively simple smart antenna techniques when applied to the third-generation W-CDMA air interface. Methods to achieve this goal include fixed multibeam architectures with different beam selection algorithms (maximum power criterion, combined beams) or adaptive solutions driven by relatively simple direction finding algorithms. After comparing these methods against each other for several representative scenarios, some issues related to the sensitivity of these methods are also studied, (e.g., robustness to environment, mismatches originating from implementation limitations, etc.). Results indicate that overall, conventional beamforming seems to be the best choice in terms of balancing the performance and complexity requirements, in particular when the problem with interfering high-bit-rate W-CDMA users is considered.

Subcarrier allocation algorithms for multicellular OFDMA networks without Channel State Information

Scope of this paper is to analyse four subcarrier allocation algorithms for multicellular OFDMA networks, namely coordinated, sequential, random and an innovative technique of cell splitting, that uses both random and coordinated subcarrier allocation. Common characteristic of these subcarrier allocation algorithms is that they do not require knowledge of channel state information (CSI) at the transmitter, a fact that leads to more efficient use of available bandwidth, lower algorithmic complexity and faster decision making. The algorithms are studied for an OFDMA multicellular network. Simulation results show that a multicellular OFDMA network is able to provide real broadband wireless access, with offered bit rate to reach 20 Mbps per cell, even without CSI knowledge.

Parallel radio-wave propagation modeling with image-based ray tracing techniques

Ray tracing is a technique based on the numerical simulation of geometrical optics and the uniform theory of diffraction, two well-known approximate methods for estimating a high-frequency electromagnetic field, based on the ray theory of field propagation. Radio-wave propagation prediction models based on ray tracing play an important role in wireless network planning, as they take into account diverse physical phenomena such as reflection, diffraction and foliage attenuation and are considered critical for the analysis of long term evolution (LTE) systems, which requires a detailed description of the wireless channel. A major practical drawback of these models is that they can easily become very computationally expensive, as the required level of accuracy and the corresponding areas of study increase. In this paper, a parallel ray tracing algorithm for radio-wave propagation prediction based on the electromagnetic theory of images is presented. The implementation of the algorithm is based on the message passing interface (MPI). The decomposition of the problem is conducted by partitioning the image tree, while dynamic load balancing techniques are employed by means of the master-worker and the work-pool patterns. The performance of the parallel implementation is studied for different problems and task assignment schemes, showing that high speedups can be achieved.

Performance enhancement of DS-CDMA microcellular networks with adaptive antennas

This paper considers the performance of a DS-CDMA system which employs adaptive antenna technology at the base station site of a microcell. By utilising the capability of ray-tracing to provide the complex channel impulse response, a new ray-based simulation methodology for an adaptive antenna in a DS-CDMA system is presented. Results for a typical microcellular environment highlight the behaviour of the adaptive antenna. Finally, with the help of a Monte-Carlo type DS-CDMA capacity analysis, the potential performance enhancement and the sensitivity of the system upon the misspointing of the main beam, are evaluated.