Sample-Selection Method for Arbitrary Fading Emulation Using Mode-Stirred Chambers

Abstract

Abstract-Mode-stirred chambers (MSCs) consist of one or more resonant cavities coupled in some way in order to allow the measurement of different antenna parameters such as antenna efficiency, correlation, diversity gain, or multiple-input-multiple-output (MIMO) capacity, among others. In a single-cavity MSC, also known as a reverberation chamber (RC), the environment is isotropic and the amplitude of the signal is Rayleigh distributed. Real environments, however, rarely follow an isotropic Rayleigh-fading scenario. Previous results have shown that a Rician-fading emulation can be obtained via hardware modification using an RC. The different methods lack from an accurate emulation performance and are strongly dependent upon chamber size and antenna configurations. With the innate complexity of more-than-one-cavity MSC, the coupling structure generates sample sets that are complex enough so as to contain different clusters with diverse fading characteristics. This letter presents a novel method to accurately emulate a more realistic Rician-fading distribution from a Rayleigh-fading distribution by selecting parts of the sample set that forms different statistical ensembles using a complex two-cavity multi-iris-coupled MSC. Sample selection is performed using a genetic algorithm. Results demonstrate the potential of MSCs for versatile MIMO fading emulation and over-the-air (OTA) testing. The method is patent protected by EMITE Ing., Murcia, Spain.Index Terms-Diversity gain, mode-stirred chamber (MSC), multiple-input-multiple-output (MIMO) capacity.

Limit for the proportion of remaining samples in the mode‐stirred chamber sample selection technique

“…Recently, the sample selection technique [5][6][7] has been introduced for the purpose of improving the versatility of MSC measurements. In the sample selection technique, some measurement samples are selected while the rest are discarded, so that the selected sample set conforms to a predetermined probability density function (PDF).…”

“…Adaptive optics (AO) is a widely used concept and technology in astronomy to compensate the atmospheric turbulence that confines the performance of ground-based telescope [1][2][3]. In addition, the biological potentials such as correction of the ocular aberration for the improved in vivo imaging of the retina in vision science and ophthalmic applications are of recent thrust areas in research [4][5][6][7][8][9]. In microscopy, AO has also been applied to nonlinear microscopies such as multiphoton microscopy to image several layers of mismatched and inhomogeneous refractive index [10].…”

Sample Selection Algorithms for Enhanced MIMO Antenna Measurements Using Mode-Stirred Reverberation Chambers

“…Among these recent enhancements, the authors have recently presented a novel technique to emulate different amplitude PDF of fading distributions by sample selection [27]. By keeping or discarding samples from a large measured sample set it is possible to achieve a new arbitrary amplitude PDF which only consists of unmodified measured samples.…”

“…By keeping or discarding samples from a large measured sample set it is possible to achieve a new arbitrary amplitude PDF which only consists of unmodified measured samples. The short contribution in [27] was limited to one MSRC, the use of Rayeigh-fading initial data and only Rician-fading target PDFs. In this paper several algorithms for the sample selection technique presented in [27] are analysed and compared with the use of both simulated and measured data, for two different MSRCs and targeting Rician-, on-body and standardized fading models amplitude PDFs.…”

“…The short contribution in [27] was limited to one MSRC, the use of Rayeigh-fading initial data and only Rician-fading target PDFs. In this paper several algorithms for the sample selection technique presented in [27] are analysed and compared with the use of both simulated and measured data, for two different MSRCs and targeting Rician-, on-body and standardized fading models amplitude PDFs. The analyses are performed in respect of distribution accuracy and computational time in an attempt to approach quasi-real-time operation of the new technique.…”