Microwave Simulation of Grover's Quantum Search Algorithm

An analog of a quantum search method, known as Grover's algorithm, is modeled without entanglement on the macroscopic level, using numerical simulation of microwave devices and methods. An array of microstrip annular-ring resonators simulates a quantum bit array. An oracle that performs a test to determine which element in the array is the answer to the search algorithm is provided by a microwave-frequency plane wave, modulated by a Gaussian pulse. A single annular ring with a resonant frequency identical to the frequency of the incident pulse serves as the answer to the search. It is shown that the number of Gaussian pulses needed to identify the answer element is equal to the radicN iterations predicted by the Grover algorithm. The decay in a microwave-resonator element is used to show that the quantum dual - a spontaneous decay of the excited energy level of a quantum bit, also described as its decoherence - can be a serious obstacle to the development of large quantum-bit data arrays     

Design of UWB switched gain controlled LNA using 0.18 μm CMOS

A switched gain controlled low noise amplifier (LNA) for the 3.1- 4.8 GHz ultra-wideband system is presented. The LNA is fabricated with the 0.18 mum 1P6M standard CMOS process. Measurement of the LNA was performed using an RF probe station. In gain mode, measured results show a noise figure of 4.68-4.97 dB, gain of 12.5-13.9 dB, and input/output return loss higher than 10/8.2 dB. The input IP3 (IIP3) at 4.1 GHz is 1 dBm, and consumes 14.6 mW of power. In bypass mode, measured results show a gain of-7.0 to -8.7 dB, and input/output return loss higher than 10/6.3 dB. The input IP3 at 4.1 GHz is 9.2 dBm, and consumes 1 muW of power.     

An Architecture for Service Quality Management Using Cooperative Communications

The rapid enhancement and explosive expansion of mobile communication systems will lead to an increased demand for multimedia services. Various multimedia contents will be available due to the proliferation of IPTV, video on demand, user-generated content, and content-centric networking. Therefore, multimedia service quality is becoming a critical issue. The static allocation of network resources may not be sufficient to guarantee the required service quality of multimedia in wireless networks. For ensuring the service quality, it is important to manage the resources considering the overall performance of the network and the end system. In particular, a certain level of service quality should be maintained regardless of the network situation. To achieve this objective, we first propose an architecture for service quality management and then present a detailed framework and mechanisms to maintain the desired service quality using the cooperation between communication entities in wireless networks. Simulation results are also presented to show that the proposed framework works well in wireless networks.     

Efficient deep-blue emitters based on triphenylamine-linked benzimidazole derivatives for nondoped fluorescent organic light-emitting diodes

Two triphenylamine-substituted benzimidazole derivatives were synthesized for use as efficient deep-blue emitters in nondoped fluorescent organic light-emitting diodes (FLOLEDs). The molecular design of 4′,4′′-(1H-benzo[d]imidazole-1,2-diyl)bis(N,N-diphenylbiphenyl-4-amine) (T2B) to limit the molecular packing density enabled T2B-based devices to suppress the exciton quenching by a bulky three-dimensional structure. Nondoped FLOLEDs fabricated using T2B as a blue emitter exhibited an external quantum efficiency of 4.67% with color coordinates of (0.15, 0.08).     

Uniform and piecewise uniform lattice vector quantization formemoryless Gaussian and Laplacian sources

Lattice vector quantizer design procedures for nonuniform sources are presented. The procedures yield lattice vector quantizers with excellent performance and retaining the structure required for fast quantization. Analytical methods for truncating and scaling lattices to be used in vector quantizations are given, and their utility is demonstrated for independent and identically distributed (i.i.d.) Gaussian and Laplacian sources. An analytical technique for piecewise linear multidimensional compandor designs is evaluated for i.i.d. Gaussian and Laplacian sources by comparing its performance to that of the other vector quantizers     

Highly stable optical add/drop multiplexer using polarization beam splitters and fiber Bragg gratings

We demonstrate a novel wavelength-division add/drop multiplexer employing fiber Bragg gratings and polarization beam splitters. The multiplexer is easy to fabricate without any special technique such as UV trimming, and yet shows very stable performance with less than 0.3-dB crosstalk power penalty in a 0.8-nm-spaced, 2.5-Gb/s-per-channel wavelength-division multiplexing (WDM) transmission system.     

Fabrication of V-grooved inner stripe GaAs-AlGaAs quantum-wire lasers

V-grooved inner stripe (VIS) GaAs-AlGaAs quantum-wire (QWR) lasers were successfully fabricated by, combining two-step metalorganic chemical vapor deposition (MOCVD) growth with a wet-etching technique. In order to achieve low threshold current density and high reliability, a conductive stripe width (W), a thickness (t/sub p-CBL/), and a doping concentration (n/sub p-CBL/) of the p-GaAs current-blocking layer (CBL) were determined to be W=1.2 /spl mu/m, t/sub p-CBL/=2 /spl mu/m, and n/sub p-CBL/=1/spl times/10/sup 18/ cm/sup -3/. The leakage currents passing through the CBL were also estimated using a modified P-SPICE. Thus far, a threshold current of 45 mA and an output power of 4 mW at 51 mA have been achieved under room-temperature pulsed operation for some devices with uncoated facets.     

VLSI array algorithms and architectures for RSA modularmultiplication

We present two novel iterative algorithms and their array structures for integer modular multiplication. The algorithms are designed for Rivest-Shamir-Adelman (RSA) cryptography and are based on the familiar iterative Horner's rule, but use precalculated complements of the modulus. The problem of deciding which multiples of the modulus to subtract in intermediate iteration stages has been simplified using simple look-up of precalculated complement numbers, thus allowing a finer-grain pipeline. Both algorithms use a carry save adder scheme with module reduction performed on each intermediate partial product which results in an output in carry-save format. Regularity and local connections make both algorithms suitable for high-performance array implementation in FPGA's or deep submicron VLSI. The processing nodes consist of just one or two full adders and a simple multiplexor. The stored complement numbers need to be precalculated only when the modulus is changed, thus not affecting the performance of the main computation. In both cases, there exists a bit-level systolic schedule, which means the array can be fully pipelined for high performance and can also easily be mapped to linear arrays for various space/time tradeoffs     

CDMA Mobile System Testbed and Field Test

This paper briefly explains the configuration of CDMA Mobile System (CMS) test bed. The measured fading and delay results of CDMA signal in Taejon area are shown. In comparison to other cellular systems, there are more parameters in the CDMA systems that affect system performance and capacity. We performed the optimization test of the selected parameters and present the effect of each parameter on the performance. This paper presents the capacity and performance test results of CMS. The capacity test was performed on ETRI site of three sectors in Taejon area. The performance tests include call completion rate, busy hour call attempt, and the delay characteristics of voice.