A differential input non-coherent BPSK receiver for the UWB-IR communication, based on threshold detection, has been presented in this paper. The chip can recover BPSK modulated Gaussian monocycle pulses (GMP), along with its first derivative, at a data rate of 500 Mb/s. No clock reception is required, as the receiver recovers data based on the relative phase of the two simultaneously received inputs. While retrieving the data, it consumes a power of 63 mW from a supply voltage of 1.8 V. A shunt-peaked narrow band amplifier, matched to the input antenna, is used to amplify the received GMP. Wireless data have been successfully recovered using a pair of horn antennas at a distance of 6 cm. The chip, developed in a 180 nm CMOS technology, occupies a die area of 3.4 mm2. The receiver is suitable for the non-coherent (self-synchronized) UWB-IR communication.

The extended binary phase shift keying (EBPSK) transmission system with ultra narrow bandwidth has excellent BER performance, which raises many doubts with the researchers. Therefore, on the premise of the existence of a special filter that can transform the modulated phase information into amplitude information, the theoretical BER formula of EBPSK system in Additive White Gaussian Noise (AWGN) channel has been deduced. This paper gives the theoretical values of the parameters in the above BER formula and discusses the effects of parameters on BER firstly. Then the paper shows that the special impacting filter satisfies the above assumption, therefore, in the frame of binary detection theory, the excellent performance of high-efficiency EBPSK system can be explained and the correction of the theoretical BER formula can be validated.

In this paper, a joint optimal design is investigated for orthogonal frequency division multiplexing (OFDM) systems to reduce peak interference-to-carrier ratio (PICR), out-of-band power (OBP) emissions, and peak-to-average power ratio (PAPR). Two approaches, namely, the phase rotation approach and the constellation extension approach, are proposed to convert this joint design problem into a second order cone programming (SOCP) problem, whose global optimal solution has been shown to exist and can be obtained efficiently. Simulation results are presented to demonstrate efficacy of the proposed algorithms in joint PICR, OBP, and PAPR reduction.

A CMOS detection procedure for ultra-wideband impulse radio (UWB-IR) communication system, employing Bi-Phase Shift Keying (BPSK) modulation scheme, is presented here. The chip was designed and fabricated in a 180 nm CMOS process and it requires a supply voltage of 1.8 V, with a die area of 0.01 mm2. A train of Gaussian Monocycle Pulses (GMP), modulated by a random data sequence of 1 Gb/s, has been detected successfully by the detector. Ability to process differential data without using conventional blocks like mixer, correlator etc. while consuming a very low power (3.8 pJ/bit for a data rate of 1 Gb/s) is the novelty of this work. The detection scheme employing a simple architecture with a noncoherent detection mechanism is well suited for UWB-IR communication system.

This Letter presents the matched subspace detection in the presence of Gaussian background with known covariance structure but different variance for hypothesis H0 and H1. The performance degradation has been evaluated when there are the following mismatches between the actual and designed parameters: background variance in the case of hypothesis H1 and one-lag correlation coefficient of background. It has been shown that the detectability depends strongly on the fill factor of targets in the case of the mode signal matrix with high rank for a prescribed false alarm probability and a given signal-to-background ratio. These results have been also justified via Monte Carlo simulations for an example scenario.

A mixed-mode high-speed binary phase-shift keying (BPSK) demodulator for IEEE802.15.3c mm-wave wireless personal area network (WPAN) application is realized with 0.18-µm CMOS process. The proposed demodulator scheme does not require any analog-to-digital converters (ADC) and, consequently, can have advantages over the conventional schemes for high-data-rate demodulation. The demodulator core consumes 53.8 mW from 2.5-V power supply while the chip area is 380500 µm2. The fabricated chip is verified by 60-GHz wireless link tests with 1.6-Gb/s data.

For over 40-Gbps optical communication systems, phase coded modulation formats, like differential phase shift keying (DPSK) and quadrature phase shift keying (QPSK), are very important for signal frequency efficiency and long-reach transmission. In such systems, differential receivers which regenerate phase signals are key components. Dual Photo Diodes (dual PDs) are key semiconductor devices which determine the receiver performance. Each PD of the dual PDs should realize high speed performance, high responsibility and high input power operation capability. Highly symmetrical characteristics between the two PDs should be also realized, thus the dual PDs are desired to be monolithically integrated to one chip. In this paper, we describe the design, fabrication, characteristics and reliability of monolithically integrated dual evanescently coupled waveguide photodiodes (EC-WG-PDs) for the purpose described above. The structure of the EC-WG-PDs offers the attractive advantages of high speed performance, high responsivity and high input power operation. Furthermore, their fabrication process is suitable for the integration of two PDs on one ship. First, the optimization was done for high products of 3-dB bandwidth and responsivity for 43-Gbps DPSK receivers. Excellent characteristics (50 GHz bandwidth with a responsivity of 0.95 A/W), and high reliability were demonstrated. The other type of optimization was done for ultra high speed operation up to 100-Gbps. The fabricated PDs exhibited the 3 dB-bandwidth of 80 GHz with a responsivity of 0.25 A/W. Furthermore, 43-Gbps RZ-DPSK receivers including the dual EC-WG-PDs based on the former optimization and differential transimpedance amplifiers (TIAs) newly developed for the purpose were also presented. Clear and symmetrical eye openings were observed for both ports. The OSNR characteristics exhibited 14.3 dB at a bit error rate of 10-3 that is able to be recovery with FEC. These performances are enough for practical use in 43-Gbps RZ-DPSK systems.

ICI (Inter-Cell Interference) mitigation schemes at the cell border are frequently dealt with as a special issue in 3GPP LTE (Long Term Evolution). However, few papers have analyzed the outage performance for the ICI mitigation schemes. In this paper, we propose a generalized cell planning scheme termed QBPA (Quality of Service based Band Power Allocation). Utilizing the QBPA scheme, we measure how much increase in channel capacity can be obtained through the flexible control of bandwidth and power in multi-cell forward-link environments. In addition, the feasible performance of the conventional schemes can be evaluated as long as those schemes are specific forms of the QBPA.

This paper presents Probabilistic Bi-polar Radial Reach Correlation (PrBPRRC), a change detection method that is robust against illumination changes and background movements. Most of the traditional change detection methods are robust against either illumination changes or background movements; BPRRC is one of the illumination-robust change detection methods. We introduce a probabilistic background texture model into BPRRC and add the robustness against background movements including foreground invasions such as moving cars, walking people, swaying trees, and falling snow. We show the superiority of PrBPRRC in the environment with illumination changes and background movements by using three public datasets and one private dataset: ATON Highway data, Karlsruhe traffic sequence data, PETS 2007 data, and Walking-in-a-room data.

A new comprehensive method to suppress the spurious modes in a BPF is proposed taking the multi-strip resonator BPF as an example. It consists of disturbing the resonant frequency, coupling coefficient and external Q of the higher-order modes at the same time. The designed example has shown an extraordinarily good out-of-band response in the computer simulation.

In this paper, a modified Belief Propagation (BP) decoding algorithm for low-density parity check (LDPC) codes based on minimum mean square error (MMSE) criterion is proposed. This modified algorithm uses linear equation to replace the hyperbolic function in the original BP algorithm and optimizes the linear approximation error based on MMSE criterion. As a result, compared with the standard BP algorithm the computational complexity is reduced significantly as the modified algorithm requires only addition operations to implement. Besides that simulation results show our modified algorithm can achieve an error performance very close to the BP algorithm on the additive white Gaussian noise channel.

In this paper, we propose a novel Web service composition framework which dynamically accommodates various failure recovery requirements. In the proposed framework called Adaptive Failure-handling Framework (AdaFF), failure-handling submodules are prepared during the design of a composite service, and some of them are systematically selected and automatically combined with the composite Web service at service instantiation in accordance with the requirement of individual users. In contrast, existing frameworks cannot adapt the failure-handling behaviors to user's requirements. AdaFF rapidly delivers a composite service supporting the requirement-matched failure handling without manual development, and contributes to a flexible composite Web service design in that service architects never care about failure handling or variable requirements of users. For proof of concept, we implement a prototype system of the AdaFF, which automatically generates a composite service instance with Web Services Business Process Execution Language (WS-BPEL) according to the users' requirement specified in XML format and executes the generated instance on the ActiveBPEL engine.

In this paper, throughput and error performance analysis is conducted on the proposed space-time resource management (STRM) scheme to realize a multi-Gbps millimeter-wave wireless personal area network (WPAN) system. The proposed STRM allows multiple peer-to-peer communication links to occupy the same time-division-multiple-access (TDMA) time slot, in contrary to the conventional TDMA system that allocates only one time slot to one communication link. Theoretical analysis is performed to investigate the achievable system throughput in the presence of co-channel interference (CCI) generated by communication links co-sharing the same time slot. To increase accuracy, the analysis results are validated by Monte Carlo simulations. Firstly, it is found that the upper bound of the achievable throughput increases linearly with the number of communication links sharing the same time slot. However, optimum throughput exists corresponding to the CCI present in the system. Secondly, by manipulating a parameter that controls the allowable CCI in the network, the system throughput can be optimized. Lastly, it is also found that in a millimeter-wave band system, a victim system with transmitter-receiver separation of 1-meter can achieve bit error rate (BER) of 10-6 provided that the interferer is at least 6-meters away.

This Letter proposes a new kind of features for color image retrieval based on Distance-weighted Boundary Predictive Vector Quantization (DWBPVQ) Index Histograms. For each color image in the database, 6 histograms (2 for each color component) are calculated from the six corresponding DWBPVQ index sequences. The retrieval simulation results show that, compared with the traditional Spatial-domain Color-Histogram-based (SCH) features and the DCTVQ index histogram-based (DCTVQIH) features, the proposed DWBPVQIH features can greatly improve the recall and precision performance.

Though millimeter wave applications have attracted much attention in recent years, they have not yet been put to practical use. The major reason for the failure may be a large transmission loss peculiar to the short wavelength. In order to overcome the inconvenience, it may be promising to introduce the technology of millimeter-wave NRD-guide circuits. In this technology, not only NRD-guide but also Gunn diodes and Schottky diodes play the important role in high bit-rate millimeter-wave applications. A variety of practical millimeter wave wireless systems have been proposed and fabricated. Performances and applications of them are discussed in detail as well.

We have developed a high-speed electroabsorption modulator integrated distributed feedback (EA/DFB) lasers. Transmission performance over 10 km was investigated under 25 Gbps and 43 Gbps modulation. In addition, the feasibility of wide temperature range operation was also investigated. An uncooled EA/DFB laser can contribute to the realization of low-power-consumption, small-footprint and cost-effective transceiver module. In this study, we used the temperature-tolerant InGaAlAs materials in an EA modulator. A wide temperature ranged 12 km transmission with over 9.6 dB dynamic extinction ratio was demonstrated under 25 Gbps modulation. A 43 Gbps 10 km transmission was also demonstrated. The laser achieved a clear, opened eye diagram with a dynamic extinction ratio over 7 dB from 25 to 85. The modulated output power was more than +2.9 dBm even at 85. These devices are suitable for next-generation, high-speed network systems, such as 40 Gbps and 100 Gbps Ethernet.

The heart rate variability (HRV) is a measure based on the time position of the electrocardiogram (ECG) R-waves. There is a discussion whether or not we can obtain the HRV pattern from blood pressure (BP). In this paper, we propose a method for estimating HRV from a BP signal based on a HIF algorithm and carrying out experiments to compare BP as an alternative measurement of ECG to calculate HRV. Based on the hypotheses that ECG and BP have the same harmonic behavior, we model an alternative HRV signal using a nonlinear algorithm, called heart instantaneous frequency (HIF). It tracks the instantaneous frequency through a rough fundamental frequency using power spectral density (PSD). A novelty in this work is to use fundamental frequency instead of wave-peaks as a parameter to estimate and quantify beat-to-beat heart rate variability from BP waveforms. To verify how the estimate HRV signals derived from BP using HIF correlates to the standard gold measures, i.e. HRV derived from ECG, we use a traditional algorithm based on QRS detectors followed by thresholding to localize the R-wave time peak. The results show the following: 1) The spectral error caused by misestimation of time by R-peak detectors is demonstrated by an increase in high-frequency bands followed by the loss of time domain pattern. 2) The HIF was shown to be robust against noise and nuisances. 3) By using statistical methods and nonlinear analysis no difference between HIF derived from BP and HRV derived from ECG was observed.

We propose a selective detection scheme based on pulse repetition considering both BER (Bit Error Rate) performance and complexity in coherent UWB (Ultra Wide Band) systems. To take system complexity into account, the proposed scheme transmits the UWB signals by pulse repetition at the transmitter, like conventional PRC (Pulse Repetition Coding). However, to effectively improve BER performance of the system, the proposed scheme performs selective detection by estimating the SNR (Signal-to-Noise Ratio) of the received pulse-repeated signal at the UWB receiver.

In this paper, we propose a method for enhancing performance of a sequential version of the belief-propagation (BP) decoding algorithm, the group shuffled BP decoding algorithm for low-density parity-check (LDPC) codes. An improved BP decoding algorithm, called the shuffled BP decoding algorithm, decodes each symbol node in serial at each iteration. To reduce the decoding delay of the shuffled BP decoding algorithm, the group shuffled BP decoding algorithm divides all symbol nodes into several groups. In contrast to the original group shuffled BP, which automatically generates groups according to symbol positions, in this paper we propose a method for grouping symbol nodes which generates groups according to the structure of a Tanner graph of the codes. The proposed method can accelerate the convergence of the group shuffled BP algorithm and obtain a lower error rate in a small number of iterations. We show by simulation results that the decoding performance of the proposed method is improved compared with those of the shuffled BP decoding algorithm and the group shuffled BP decoding algorithm.

All-optical wavelength conversion and modulation format conversion will be needed in the next generation high-speed optical communication networks. We have proposed and successfully demonstrated the error free operation of all-optical modulation format conversion from NRZ-OOK to RZ-BPSK using SOA based MZI wavelength converter. In this paper, we experimentally investigate the wavelength conversion characteristics of the proposed NRZ-OOK/RZ-BPSK modulation format converter. The results show that error free modulation format conversion is possible over the entire C band.