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Directional measurements of over 2600 links in four distinct factories at 28 GHz are used to formulate the path gain and azimuth gain models to allow reliable 90% coverage estimates. A simple theoretical model of path gain, dependent on ceiling and clutter heights, is found to represent path gain across the four factories with 4.4 dB root-mean-square error (RMSE), contrasted with 6.9 dB slope-intercept fit and 8.5–14.9 dB RMSE for 3GPP factory models. The model also did well against 3.5 GHz path loss data collected over 18 MHz bandwidth in one of the factories, with an RMSE of 3.3 dB. In nonline-of-sight (NLOS) conditions, scattering reduces available antenna azimuth gain from nominal value by up to 7.3 dB in 90% of links. Line-of-sight (LOS) blockage by a 1.7 m × 1 m obstacle in factory aisle leads to 7 dB signal reduction, attributed to availability of other paths. It is found that an access point (AP) using 25 dBm transmit power per polarization, with 23 dBi nominal gain and omnidirectional terminals, supporting $2\times $ 2 MIMO in a 400 MHz bandwidth, can provide 130 Mb/s for 90% of factory locations within 50 m. [ABSTRACT FROM AUTHOR]

Path gain and effective directional gain in azimuth in urban canyons from actual rooftop base station sites are characterized based on a massive data set of 3000 links on 12 streets in two cities, with over 21 million individual continuous-wave power measurements at 28 GHz using vertically polarized antennas. Large street-to-street path gain variation is found, with median street path gain varying over 30 dB at similar distances. Coverage in the street directly illuminated by a roof edge antenna is found to suffer an average excess loss of 11 dB relative to free space at 200 m, with an empirical slope-intercept fit model representing the data with 7.1 dB standard deviation. Offsetting the base antenna 5 m away from the roof edge, as is common in macrocellular deployments, introduces an additional average loss of 15 dB at 100 m, but this additional loss reduces with distance. Around the corner loss is well modeled by a diffraction formula with an empirically obtained diffraction coefficient. Effective azimuthal gain degradation due to scatter is limited to 2 dB for 90% of data, supporting effective use of high-gain antennas in urban street canyons. [ABSTRACT FROM AUTHOR]

The major computation cost of pseudo-spectral method comes from the evaluation of differentiation matrix multiplication. In the past, uniform or Chebyshev collocation points are used for sampling. The differentiation matrix multiplication was evaluated by fast Fourier transform (FFT) or fast cosine transform (FCT), in order to reduce the computation complexity from O(N2) to O(N log(N)). However, the intrinsic properties of FFT or FCT may cause the wraparound effect and Gibbs phenomenon. Moreover, FFT or FCT is not applicable to other collocation points such as Legendre and Hermite. In order to improve the accuracy and applicability of the pseudo-spectral method, the fast multipole method (FMM) is exploited to substitute the FFT or FCT. By making use of the similarity of the N-body problem and the collocation problem, a new FMM-based pseudo-spectral time domain method is developed in this paper. [ABSTRACT FROM AUTHOR]

Empirical results on indoor multiple input multiple output (MIMO) channel capacity obtained through the use of planar inverted-F antennas (PIFA) are presented. An extensive statistical study done at 2.45 GHz reveals how antenna proximity and array configuration affects MIMO capacity. It is concluded that certain linear or square PIFA based arrays allow very compact multi-antenna arrangements without significant capacity loss. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1754–1756, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22526 [ABSTRACT FROM AUTHOR]