Specular Power Research Articles

Effective rate analysis of MISO over Beaulieu-Xie fading channel

This paper presents the effective rate (ER) analysis of a multiple input single output (MISO) system over the Beaulieu-Xie (BX) fading. The closed-form expressions were derived for the exact and asymptotic cases (for high and low signal-to-noise ratio (SNR)). The BX fading channel is extremely useful for characterizing small cell networks, hyper-dense networks, and femtocells, etc. It can also be used for modeling the fading channels for high-speed trains. Numerical results were presented using the derived closed-form expressions and compared with the results obtained from Monte Carlo simulations. Our findings illustrated that the analytical results have a close match with simulation results. In addition, the numerical findings also provide the important insights into the impact of delay constraint and fading parameters on the ER of considered wireless scenario. It is found that the performance of system improves as dominant specular power and/or number of transmitter antennas increases or the delay constraint parameter decreases.

Link Quality Estimation in Industrial Temporal Fading Channel With Augmented Kalman Filter

Wireless networks attract increasing interests from a variety of industry communities. However, the wide applications of wireless industrial networks are still challenged by unreliable services due to severe multipath fading effects. Such effects are not only caused by massive metal surfaces but also moving operators and logistical vehicles, which will lead to temporal fading effects. A three-layer impulse response framework is proposed to characterize such effects, in which both the specular and scattered components vary with the spacial movement of nearby objects. In this context, a received signal strength indicator will be a noisy estimation only on the specular power and fail to describe the link quality accurately without the aid of scattered power. Consequently, an augmented Kalman-filter-based link quality estimator has been designed to track both the specular and scattered power in the distribution parameter space with constant noise covariance matrices. Experiments from industrial sites show significantly increased accuracy.

Propagation measurements for fixed wireless loops (FWL) in a suburban region with foliage and terrain blockages

We present the results of propagation measurements at 2.485 GHz for fixed wireless loops. Path loss measurements were performed and characterized at 43 subscriber locations around a base station antenna located on top of Crawford Hill in Holmdel, NJ. This suburban location is characterized by rolling hills, foliage, and terrain blockages. Temporal and horizontal motion path loss fluctuations were found to be uncorrelated, each characterized by a different Ricean distribution. Lower r.m.s. delay spreads were obtained with directive subscriber antennas than with omni-directional antennas. No substantial gain loss (less than 2 dB) of subscribers' directive antennas was observed. The effects of trees, with foliage, surrounding the base station upon the path loss and the ratio of scattered power to specular power are also examined. The distance exponent of path loss versus distance (about 1.5) was observed to be less than free-space. Diffraction loss from hilltop trees, shadowing the base station, are suspected to be the cause. This loss decreases as the remote moves further away and comes out of the shadow. Scattered power from directions other than line-of-sight was observed to be as high as one half of the specular contribution when tree scattering near the base station was significant.

Blood, Bodies, and The Lifted Veil

The Lifted Veil (1859) is a text concerned with the interplay between science and the imagination. It is informed by The Physiology of Common Life, the work that G. H. Lewes published in the same year, and in many ways is in a dialogue with this work, asking that if we could look into someone's mind with the same power that a physician can examine the body, would we choose to exercise this specular power? The essay shows how George Eliot employs some of the same language that Lewes uses in his scientific writing, especially in the context of the circulation of blood and the circulation of feeling. Blood is crucial to this novella, and its wider nineteenth-century implications are also raised. In particular, the blood transfusion scene in The Lifted Veil is shown not to be a piece of mere Gothic melodrama but to be rooted in contemporary debate about transfusion. Historical specificity is reinforced through showing that Meunier, the doctor, had an actual prototype in the figure of Brown-Séquard. Examining these aspects of the novella raises questions about gender and authority. It is argued that, despite the dialogue with Lewes's work that occurs in The Lifted Veil, George Eliot gives even greater priority than Lewes does to the role of the imagination and to the provocative nature of that which cannot be revealed by science.

Multiple hops/symbol FFH-SSMA with MFSK modulation and Reed-Solomon coding for indoor radio

A multiple-hopes-per-symbol fast-frequency-hopped spread-spectrum multiple-access (FFH-SSMA) system for indoor radio communication is treated. The data are Reed-Solomon (RS) encoded and then modulate a carrier by means of M-ary frequency-shift-keying (MFSK) The indoor radio channel is described as a multipath (Rayleigh or Rician) slowly fading channel. The receiver uses predetection diversity by linearly combining the squared enveloped of the different hops of the same MFSK symbol. The bit error rate (BER) performane is evaluated, and how the performance is influenced by various parameters, such as the number of hops per symbol, the size of the symbol alphabet, the ratio of specular power to fading power, and the ratio of nonreference user power to reference user power, is investigated. >

Venus: Surface electromagnetic properties

Using Pioneer Venus high‐angle radar imaging data, we have attempted to correct values of the specular power reflection coefficient, previously reported by the Pioneer Venus radar altimetry experiment, for the effects of diffusely scattering small‐scale surface roughness. We have compared these results with values of surface radio emissivity obtained both from the Pioneer Venus radar altimetry experiment and from thermal radioemission observations of Venus made at the Very Large Array. The combined measurements provide credible estimates of the relative dielectric permittivity (ε) at 17‐cm wavelength for the majority of the Venus surface. The lowland regions are characterized by ε = 5.0 ±0.9, a value commonly associated with many types of compact dry basaltic or granitic rocks. Most highland areas, however, display very much larger values, rising to as high as ε = 39 ± 15 over Maxwell Montes. If the high values of permittivity derive from the loading of a host rock matrix with small embedded fragments of an electrically conducting mineral, as we believe, the required volume fraction of this material for Maxwell is about 14%, with many other highland regions containing as much as 10%. Suitable candidates for the conducting mineral are pyrite, other iron sulfides, or, depending on the oxidation state of the surface, possibly magnetite, hematite, or ilmenite.

Scattering from a class of randomly rough surfaces

This paper develops new results pertaining to electromagnetic scattering from perfectly conducting random surfaces for which decorrelation does not imply statistical independence. Using an exact theory for the current induced on the surface and the far‐field approximation for the scattered field, it is shown that the incoherent scattered power consists of two parts. The first part corresponds to the so‐called diffuse scattered power. The second part is specular in its angular dependence and is a direct consequence of the fact that the two‐point joint density for the surface height, slopes, etc., does not reduce to the product of the single‐point joint densities for infinite separation distances. Computations for a gently undulating jointly exponentially distributed surface show that the incoherent specular power is equal to coherent scattered power for the Rayleigh parameter near 1. When the Rayleigh parameter is large, the incoherent specular power is significantly larger than the coherent power. The analysis further indicates that scattering measurements provide an ideal way for identifying this class of surfaces.