Improving of Wavelength Division Multiplexing Based on Free Space Optical Communication via Power Comparative System

Wireless Personal Communications - The names of the second and third authors in the initial online publication were not correctly typeset. The original article has been corrected.     

Analytical modeling of the partially-depleted SOI MOSFET

An analytical model for the partially-depleted (PD) silicon-on-insulator (SOI) MOSFET above threshold was developed. In contrast to previous models, this model includes front-back interface coupling with all the possibilities associated with it (accumulated, neutral, and depleted back interface). The model applies to tied-body as well as floating-body devices; however, thermal and edge effects are neglected. Interface coupling and floating-body effects are integrated together in a new “unified” algorithm. The “pseudo-two-dimensional” approach (which was used successfully to model lateral fields in bulk-Si devices) is extended to SOI devices. The model is extremely physical and thus highly predictive. Good agreement with experiment was obtained over a wide range of channel lengths and back gate voltages. Because of the model's neglect of thermal effects, however, disagreement was observed at high current levels. A brief physical interpretation of the results is also presented     

Search me if you can: Multiple mix zones with location privacy protection for mapping services

The mobile vehicle is gaining popularity nowadays using map services like Google Maps and other mapping services. However, map services users have to expose sensitive information like geographic locations (GPS coordinates) or address to personal privacy concerns as users share their locations and queries to obtain desired services. Existing mix zones location privacy protection methods are most general purposed and theoretical value while not applicable when applied to provide location privacy for map service users. In this paper, we present new (multiple mix zones location privacy protection) MMLPP method specially designed for map services on mobile vehicles over the road network. This method enables mobile vehicle users to query a route between 2 endpoints on the map, without revealing any confidential location and queries information. The basic idea is to strategically endpoints to nearby ones, such that (1) the semantic meanings encoded in these endpoints (eg, their GPS coordinates) change much, ie, location privacy is protected; (2) the routes returned by map services little change, ie, services usability are maintained. Specifically, a mobile client first privately retrieves point of interest close to the original endpoints, and then selects 2 points of interest as the shifted endpoints satisfying the property of geoindistinguishability. We evaluate our MMLPP approach road network application for GTMobiSim on different scales of map services and conduct experiments with real traces. Results show that MMLPP strikes a good balance between location privacy and service usability.     

Design and Analysis of a Wavelet Packet Modulation Based Differential Chaos Shift Keying Communication System

Wireless Personal Communications - In this paper, a new multicarrier based DCSK system that is combined a wavelet packet modulation (WPM) with differential chaos shift keying (DCSK) and named...     

Near- and Far-Field Characterization of Planar mm-Wave Antenna Arrays with Waveguide-to-Microstrip Transition

We present the design and characterization of planar mm-wave patch antenna arrays with waveguide-to-microstrip transition using both near- and far-field methods. The arrays were designed for metrological assessment of error sources in antenna measurement. One antenna was designed for the automotive radar frequency range at 77 GHz, while another was designed for the frequency of 94 GHz, which is used, e.g., for imaging radar applications. In addition to the antennas, a simple transition from rectangular waveguide WR-10 to planar microstrip line on Rogers 3003? substrate has been designed based on probe coupling. For determination of the far-field radiation pattern of the antennas, we compare results from two different measurement methods to simulations. Both a far-field antenna measurement system and a planar near-field scanner with near-to-far-field transformation were used to determine the antenna diagrams. The fabricated antennas achieve a good matching and a good agreement between measured and simulated antenna diagrams. The results also show that the far-field scanner achieves more accurate measurement results with regard to simulations than the near-field scanner. The far-field antenna scanning system is built for metrological assessment and antenna calibration. The antennas are the first which were designed to be tested with the measurement system.     

Brookite Formation in TiO2?Ag Nanocomposites and Visible‐Light‐Induced Templated Growth of Ag Nanostructures in TiO2

TiO₂? Ag‐nanocomposites exhibit various desirable properties that make them suitable for a variety of applications, for example in photocatalysis and as bactericidal coatings. In this work, a new method for processing TiO₂? Ag nanocomposites is presented. The nanocomposite films are fabricated from one precursor solution with high silver loading of up to 50%. The resulting films exhibit a microstructure consisting of TiO₂? Ag_xO nanocomposites with a largely XRD‐amorphous TiO₂ matrix containing brookite nanocrystals. This specific microstructure absorbs in the visible range so that photoreduction of Ag ions can be accomplished by using visible light. The thin films can be patterned using simple shadow masks. The illuminated areas show a high density of self‐organized nanoparticles (SNPs) and nanorods (SNRs), which are templated by the TiO₂ porous network. The particle size can be tuned by varying the irradiation time. Most of the SNPs and SNRs form faceted crystals, which are mostly a combination of {111} and {110}. The application of these films as substrates for surface‐enhanced Raman scattering is shown. Enhancement factors as high as 4.6 × 10⁶ could be obtained using rhodamine 6G dye molecules. More applications should involve photocatalytic water purification using visible light.     

Interference coordination for LTE-Advanced and FM broadcasting interoperability

The surest way to guarantee that multiple wireless systems can concurrently exist harmlessly, when operating in the same or adjacent channel, is by analyzing spectrum overlapping. This paper proposes a more accurate model to evaluate the interference power from co-channel and adjacent channel of orthogonal frequency division multiplexing-based long term evolution-advanced (LTE-Advanced) towards broadcasting frequency modulation systems at 800?MHz. Power spectral density overlapping factor is employed, and closed form of the interference power loss is derived. Numerical results demonstrate that the proposed method evaluates more exact interference power than the advanced minimum coupling loss (A-MCL) method, where the co-channel and adjacent channel interference powers are reduced by 1.3 and 3?dB, correspondingly, compared to that obtained using the A-MCL method. This decreases the minimum separation distance between the two systems, which can eventually lead to efficient radio spectrum resources utilization.     

The accuracy of PSNR in predicting video quality for different video scenes and frame rates

Peak Signal-to-Noise Ratio (PSNR) is widely used as a video quality metric or performance indicator. Some studies have indicated that it correlates poorly with subjective quality, whilst others have used it on the basis that it provides a good correlation with subjective data. Existing literature seems to provide conflicting evidence of the accuracy of PSNR as a video quality metric. Based on experimental results, we explain a scenario where PSNR provides a reliable indication of the variation of subjective video quality and scenarios where PSNR is not a reliable video quality metric. We show that PSNR follows a monotonic relationship with subjective quality in the case of full frame rate encoding when the video content and codec are fixed. We provide evidence that PSNR becomes an unreliable and inaccurate quality metric when several videos with different content are jointly assessed. Furthermore, PSNR is inaccurate in measuring video quality of a video content encoded at different frame rates because it is not capable of assessing the perceptual trade-off between the spatial and temporal qualities. Finally, where PSNR is not a reliable video quality metric across different video contents and frame rates, we show that a perceptual video model recently approved by the International Telecommunication Union (ITU) provides quality predictions highly correlating with subjective scores even if different video scenes coded at different frame rates are considered in the test set.     

Enhanced fair earliest due date first scheduling strategy for multimedia applications in LTE downlink framework

Guaranteeing a certain delay threshold for delay‐sensitive applications in long term evolution (LTE) cellular communication system is a very challenging mission. By implementing an optimal scheduling strategy, this mission will be achieved. In this article, a novel scheduler is introduced in order to meet a predefined level of service quality by guaranteeing a specific delay threshold for delay‐sensitive applications in LTE cellular systems. The proposed scheduler assigns the available resource blocks (RBs) to active user equipments (UEs) tacking into consideration several attributes. The expiration date of each packet, the channel quality, the average data rate previously achieved by each UE, and the number of dropped packets for each UE compared with the average number of packets totally dropped are all considered in the proposed scheduler working mechanism. Consequently, the proposed scheduling strategy reduces the number of packets dropped for multimedia applications, and at the same time maximizes the overall throughput of the network. Simulation results are provided to study and evaluate the performance of the proposed scheduling strategy. A comparative study is presented between the proposed strategy and the most recent scheduling techniques. The obtained results prove that the proposed scheduling strategy has considerably acceptable and appreciated results compared with the results of the state‐of‐the‐art scheduling techniques.