Adaptive antennas and mimo systems for wireless communications: part II

Abstract

he first part of this special issue contained eight articles that presented overviews, descriptions of different methods, performance analyses, and new ideas, all from a theoretical/simulation point of view. Part II includes articles that focus more on practical and experimental issues related to the presented topic. The first article of this issue discusses the advantages of reconfigurable antennas and the requirements for radio frequency microelectromechanical systems (RF MEMS). A simplified prototype of the reconfigurable antenna is also presented along with simulation and experimental results for impedance and radiation performance. The second article discusses a classification of multiantenna testbeds for training and research purposes. The authors present the characteristics, capabilities and cost of the testbeds, highlight their role in an educational environment and provide experimental results. The following article presents a multiple-input multipleoutput orthogonal frequency-division multiplexed (MIMOOFDM) prototype for next-generation wide area wireless networks. The uplink is based on an enhanced Universal Mobile Telecommunications System (UMTS) physical layer, the downlink on shared access MIMO-OFDM with adaptive modulation and coding. Measurements for different operational scenarios demonstrate the capabilities of the system. The fourth article describes the implementation issues related to the development of a 3 × 3 OFDM Bell Labs Layered Space-Time (BLAST) testbed for wireless metropolitan area networks. It then presents initial results for the performance and complexity of three BLAST detection techniques using experimental data from an indoor environment. The fifth article first surveys the principal space-time coding/decoding technologies for MIMO wireless LAN systems. Then it describes indoor channel sounding trials and employs the results to scope the expected performance of space-time codes in realistic deployments. The next article discusses the effects of antenna mutual coupling on correlation, radiation efficiency, diversity gain, and MIMO capacity. Measurements in a reverberation chamber and simulations are also provided to support the analysis. The last article of this issue presents a discussion of the classes of distortion that affect the performance of adaptive antennas. An eight-element circular array adaptive antenna testbed is employed to illustrate the impact of temperature on performance, while design techniques for calibration are also described. I would like to thank again all the authors who submitted their articles to this feature topic and also the many reviewers who took time out of their busy schedules and did an excellent job by providing detailed reviews.