We measure the capacity of multiple-input multiple-output radio systems in microcellular environments. We use a new data evaluation method that allows to evaluate the cumulative distribution function of the capacity f...
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We measure the capacity of multiple-input multiple-output radio systems in microcellular environments. We use a new data evaluation method that allows to evaluate the cumulative distribution function of the capacity from a single measurement. This method is based on an extraction of the parameters of the multipath components and, thereafter, a synthetic variation of their phases. In the analyzed environments, we find capacities to be about 30% smaller than would be anticipated from an idealized model. In addition, the frequency selectivity of the channel makes the cdf of the capacity steeper and, thus, increases the outage capacity, compared with the frequency-flat case, but the influence on the mean capacity is small.
Multielement system capacities are usually thought of as limited only by correlations between elements. It is shown here that degenerate channel phenomena called "keyholes" may arise under realistic assumpti...
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Multielement system capacities are usually thought of as limited only by correlations between elements. It is shown here that degenerate channel phenomena called "keyholes" may arise under realistic assumptions which have zero correlation between the entries of the channel matrix H and yet only a single degree of freedom. Canonical physical examples of keyholes are presented. For outdoor environments, it is shown that roof edge diffraction is perceived as a "keyhole" by a vertical base array that may be avoided by employing instead a horizontal base array.
In this paper we present a deterministic approach of modeling wideband MIMO (multiple-input multiple-output) radio fading channel for wireless multicarrier systems. Implementation problem of downlink MIMO model for mo...
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ISBN:
(纸本)0819447005
In this paper we present a deterministic approach of modeling wideband MIMO (multiple-input multiple-output) radio fading channel for wireless multicarrier systems. Implementation problem of downlink MIMO model for mobile station (MS) was first investigated, while space-time coding or downlink beam-forming is taken into count at base station (BS). The MIMO channel are determined by both power azimuth profile (PAP) at MS and various configuration of multiple antennas at BS. Based on tap-delay-line structure and deterministic fading channel modeling method, SIMO fading model, corresponding to any one transmitter antenna, is formed by generating doppler phase difference between two receiver antenna aided by PAP at MS. The von Mises probability density function was adopted to characterize phenomenon of nonisotropic scattering components around MS. The ultimate MIMO channel simulation model is sum of all SIMO channel with all transmitter antennas. Finally, we predicted MIMO channel capacity based on proposed simulation model with parameters of wireless multicarrier systems under specified "Vehicular A channel" of ITU-R M.1225.
Control system synthesis consists of two major subtasks: selection of measurements and manipulated variables, and deciding on the structure interconnecting the measured and manipulated variables along with the control...
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Control system synthesis consists of two major subtasks: selection of measurements and manipulated variables, and deciding on the structure interconnecting the measured and manipulated variables along with the control law governing the interconnections. For multiple-input-mutiple-output systems, a decentralized control structure is generally preferred to a fully centralized structure. A major step in this controller design process is therefore the pairing problem: which manipulated variables to connect to which measurements? The answer to this question has undoubtedly to account for loop interactions that arise within the system. Work has been carried out using Relative Gain Array (RGA) and Block Relative Gain (BRG) interaction measures to develop automated pairing procedures and implement them as a portable software. A methodology involving the use of this software in conjuction with dynamic simulation and Internal Model Control design techniques for controllers was used on a particular case study to generate a satisfactory control structure.
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