Pilot-Assisted Carrier Frequency Offset Estimation for OFDM systems with Multiple Preambles Over Fast Fading Channels

This paper proposes a carrier frequency offset (CFO) estimation scheme for OFDM systems over fast fading channels. In the proposed scheme, exploiting the multiple preambles with the identical values, we estimate the CFO over fast fading channels. In particular, we improve the performance of the CFO estimator by applying the overlapped windows to preambles. Through simulations, we validate the proposed estimation scheme by showing the effectiveness of the proposed estimator.     

Optical and Electrical Properties of TixSi1‐xOy Films

Ti_xSi_1xO_y (TSO) thin films are fabricated using plasma‐enhanced atomic layer deposition. The Ti content in the TSO films is controlled by adjusting the sub‐cycle ratio of TiO₂ and SiO₂. The refractive indices of SiO₂ and TiO₂ are 1.4 and 2.4, respectively. Hence, tailoring of the refractivity indices from 1.4 to 2.4 is feasible. The controllability of the refractive index and film thickness enables application of an antireflection coating layer to TSO films for use as a thin film solar cell. The TSO coating layer on an Si wafer dramatically reduces reflectivity compared to a bare Si wafer. In the measurement of the current‐voltage characteristics, a nonlinear coefficient of 13.6 is obtained in the TSO films.     

Surface graft copolymerization enhanced adhesion of an epoxy-basedprinted circuit board substrate (FR-4) to copper

The lamination of surface modified printed circuit board (PCB) substrate, FR-4(R), from argon plasma pretreatment and UV-induced graft copolymerization with glycidyl methacrylate (GMA), to copper foil was carried out at elevated temperature and in the presence of an epoxy adhesive. The structure and chemical composition of the graft copolymerized surfaces and interfaces of the glass fiber-reinforced and epoxy-based FR-4 substrates were studied by X-ray photoelectron spectroscopy (XPS). The effects of the plasma pretreatment time, the UV illumination time, as well as the curing temperature, on the adhesion strength between the FR-4 substrate and copper were investigated. The assemblies involving GMA graft copolymerized FR-4, or the FR-4-GMA/epoxy resin/Cu assemblies, exhibited a significantly higher interfacial adhesion strength and reliability, in comparison to those assemblies in which only epoxy adhesive alone was used. The enhanced adhesion in the assemblies involving GMA graft copolymerized substrate arises from the fact that the covalently tethered GMA graft chains on the FR-4 surface can become covalently incorporated into the epoxy resin, resulting in the toughening of the epoxy matrix and increased interaction with copper     

A power-factor controller for single-phase PWM rectifiers

A novel power-factor controller for single-phase pulsewidth modulated rectifiers is proposed. The unity power-factor controller for a sinusoidal input current is derived using the feedback linearization concept. Two active switches and two diodes are utilized for AC-to-DC power conversion. Experimental results obtained on a 4 kW prototype are discussed     

Plasmonic Light Beaming Manipulation and its Detection Using Holographic Microscopy

Plasmonic off axis beaming and focusing of light by the use of asymmetric or non-periodic dielectric gratings around a metallic slit are experimentally demonstrated. The far-field probing was done by holographic microscopy. While the conventional near-field microscopes can probe only near-fields, our four-step phase-shift interferometer provides an efficient way of probing and reconstructing light paths coming out from the plasmonic devices. We hope our experimental work contributes to the practical applications of plasmonics such as optical interconnection and optical data storage.      

Efficient Generation of Scalable Transport Stream for High Quality Service in T‐DMB

We introduce an advanced terrestrial digital multimedia broadcasting (AT‐DMB) system that overcomes the limitation of data transmission rates of T‐DMB by doubling it with the same frequency bandwidth. In this letter, we propose an efficient algorithm which generates a scalable transport stream in AT‐DMB by multiplexing certain types of elementary streams encoded using scalable video coding and an MPEG‐surround audio coder for high‐quality multimedia services.     

A Novel Genetic Algorithm for the Design of a Signed Power-of-Two Coefficient Quadrature Mirror Filter Lattice Filter Bank

A novel genetic algorithm (GA) for the design of a canonical signed power-of-two (SPT) coefficient lattice structure quadrature mirror filter bank is presented in this paper. Genetic operations may render the SPT representation of a value noncanonical. In this paper, a new encoding scheme is introduced to encode the SPT values. In this new scheme, the canonical property of the SPT values is preserved under genetic operations. Additionally, two new features that drastically improve the performance of our GA are introduced. (1) An additional level of natural selection is introduced to simulate the effect of natural selection when sperm cells compete to fertilize an ovule; this dramatically improves the offspring survival rate. A conventional GA is analogous to intracytoplasmic sperm injection and has an extremely low offspring survival rate, resulting in very slow convergence. (2) The probability of mutation for each codon of a chromosome is weighted by the reciprocal of its effect. Because of these new features, the performance of our new GA outperforms conventional GAs.     

Effects of CEE and Feedback Error on Performance for AF-ORS with PSA-CE Schemes Over Quasi-Static Rayleigh Fading Channels

In this paper, we propose the analytical approach for amplify-and-forward (AF) opportunistic relaying schemes (ORS). When operation of AF-ORS consists of relay selection and data transmission phases based on pilot symbol assisted-channel estimation (PSA-CE) methods over quasi-static Rayleigh fading channels, we show that the relay selection phase can be implemented by pilots symbols transmission for source-relay and relay-destination. Moreover, the feedback method for the selected relay index is proposed to have a simple fashion. Then, we investigate the effects of both a channel estimation error and an estimated noise variance, which are obtained by PSA-CE methods, on the received signal-to-noise ratio (SNR). The average SNR loss is also derived in terms with the number of pilots in PSA-CE methods. Moreover, the average symbol error rate, the outage probability, and the normalized channel capacity of the ORS are derived in approximated closed-form expressions for an arbitrary link SNR when the channel state information in the source-relay-destination link is estimated based on transmitted pilots symbols. As the number of pilot symbols, the derived analytical approach is verified, and by comparing it with simulation results, the accuracy is demonstrated. In addition, it is verified that the effect of the feedback error can be neglected for PAS-CE methods over quasi-static fading channels.     

Design and Optimization of the Extended True Single-Phase Clock-Based Prescaler

The power consumption and operating frequency of the extended true single-phase clock (E-TSPC)-based frequency divider is investigated. The short-circuit power and the switching power in the E-TSPC-based divider are calculated and simulated. A low-power divide-by-2/3 unit of a prescaler is proposed and implemented using a CMOS technology. Compared with the existing design, a 25% reduction of power consumption is achieved. A divide-by-8/9 dual-modulus prescaler implemented with this divide-by-2/3 unit using a 0.18-mum CMOS process is capable of operating up to 4 GHz with a low-power consumption. The prescaler is implemented in low-power high-resolution frequency dividers for wireless local area network applications     

Multi-objective module placement for 3-D system-on-package

System-on-package (SOP) is a viable alternative to system-on-chip (SOC) for meeting the rigorous requirements of today's mixed-signal system integration. Thermal integrity is arguably the most crucial issue in three-dimensional (3-D) SOP due to the compact nature of the 3-D integration. In addition, the power supply noise issue becomes more serious as the supply voltage continues to decrease while the number of active devices consuming power increases. We propose a 3-D module and decap (decoupling capacitance) placement algorithm that evenly distributes the thermal profile and reduces the power supply noise. In addition, we allocate white spaces around the modules that require decaps to suppress the power supply noise while minimizing the area overhead. In our experimentation, we achieve improvements in both maximum temperature and decap amount with only small increase in area, wirelength, and runtime.