The Canonical Polyadic Decomposition (CPD) is the tensor analog of the Singular Value Decomposition (SVD) for a matrix and has many data science applications including signal processing and machine learning. For the CPD, the Alternating Least Squares (ALS) algorithm has been used extensively. Although the ALS algorithm is simple, it is sensitive to a noise of a data tensor in the applications. In this paper, we propose a novel strategy to realize the noise suppression for the CPD. The proposed strategy is decomposed into two steps: (Step 1) denoising the given tensor and (Step 2) solving the exact CPD of the denoised tensor. Step 1 can be realized by solving a structured low-rank approximation with the Douglas-Rachford splitting algorithm and then Step 2 can be realized by solving the simultaneous diagonalization of a matrix tuple constructed by the denoised tensor with the DODO method. Numerical experiments show that the proposed algorithm works well even in typical cases where the ALS algorithm suffers from the so-called bottleneck/swamp effect.

This paper presents a hardware design of high throughput, low latency preamble detector for 3GPP LTE physical random access channel (PRACH) receiver. The presented PRACH receiver uses the pipelined structure to improve the throughput of power delay profile (PDP) generation which is executed multiple times during the preamble detection. In addition, to reduce detection latency, we propose an instantaneous preamble detection method for both restricted and unrestricted set. The proposed preamble detection method can detect all existing preambles directly and instantaneously from PDP output while conducting PDP combining for restricted set. The PDP combining enables the PRACH receiver to detect preambles robustly even in severe Doppler effect or frequency error exist. Using proposed method, the worst case preamble detection latency time can be less than 1 ms with 136 MHz clock and the proposed PRACH receiver can be implemented with approximately 237k equivalent ASIC gates count or occupying 30.2% of xc6vlx130t FPGA device.

A new random access channel (RACH) preamble detection scheme using variable coherent correlation intervals (CCIs) is proposed. It is shown first that it is enough to employ two CCIs for supporting a user equipment (UE) velocity of 300 km/h, and then a CCI selection criterion is proposed. Computer simulation results indicate that the proposed scheme can provide a robust detection performance in time-varying fading channel environments.

This paper presents the optimum physical random access channel (PRACH) structure in terms of the number of control signaling bits accommodated and the transmission bandwidth based on the link budget in order to satisfy the coverage requirement for the single-carrier (SC)-FDMA based E-UTRA uplink. First, we present the design concept of the PRACH structure considering the purposes of the random access procedure in the E-UTRA. Simulation evaluations including a system-level simulation show that a PRACH comprising a 0.5-msec preamble sequence can convey a 6-bit control signal at the cell edge when the inter-site distance (ISD) is 500 m under full channel load conditions with one-cell frequency reuse. It is also shown, however, that a PRACH longer than one-sub-frame, e.g., 1.0 msec, is necessary to support the ISD of 1732 m assuming the same conditions. We also show that the best transmission bandwidth for the PRACH is approximately 1.08-4.5 MHz from the viewpoint of the misdetection probability, and a 1.08-MHz transmission bandwidth is suitable considering other aspects such as flexible resource assignment in the time domain and a small number of options in the transmission bandwidth.

In this paper, we propose a high speed Preamble Searcher suitable for the RACH (Random Access Channel) structure in WCDMA reverse link receivers. Unlike IS-95, WCDMA system uses the AISMA (Acquisition Indication Sense Multiple Access) scheme. Because of the time limit between RACH preamble transmission and AI (Acquisition Indicators), and the restriction on the number of RACH signatures assigned to RACH preamble, fast acquisition is required for efficient operation. The Preamble Searcher proposed in this paper is designed for 2-antenna systems; it adopts the FHT (Fast Hadamard Transform) algorithm that has the radix-2 16 point FFT (Fast Fourier Transform) structure. The acquisition speed using FHT is 32 times faster than the conventional method that correlates each signature. Based on this fast acquisition scheme, we improved the acquisition performance by calculating correlation up to 4096 chips of the total preamble length.

The uplink performance of WCDMA with voice and World Wide Web (WWW) traffic over Dedicated Channel (DCH)/Common Packet Channel (CPCH) is investigated. The probability of voice packet dropping and average data packet delay are obtained by system level simulation. The system level simulation is conducted based on received Signal-to-Interference Ratio (SIR) with imperfect power control. In addition, we show that the performance of CPCH in terms of probability of data packet dropping is superior to that of DCH for transmitting WWW traffic. Furthermore, we obtain the supportable number of voice users when the target probability of voice packet dropping is set to be 10-2. The supportable number of data users is also found around knee area of average data packet delay.

Simultaneous recordings of eight channel surface myoelectric signals (EMGs) of the biceps brachii muscles of seven subjects were measured in isovelocity elbow flexion against constant load torque. The velocity was 10, 15, 20 and 25 degree/s and the load torque was 5-15 % of the torque obtained at the maximum voluntary contraction (MVC). Individual motor units were identified from the eight-channel surface EMG, by tracking the waveform change which originated from the change of relative position of muscle fiber and electrode. In the low-load (5 and 7% MVC) experiment, 36 examples of recruitment and 22 examples of derecruitment were measured. In the middle-load (10 and 15% MVC) experiment, most of the motor units did not show an obvious change in the firing rate with the elbow joint angle. Average of the firing rates of all the motor units measured at the elbow angle of 0 to 120 degree (13.3-14.7 Hz) did not depend on flexion velocity between 10 to 25 degree/s. It was concluded that the firing rates of the activated MUs were almost constant and that some MUs were recruited and derecruited during the isovelocity flexion movements. These are the first findings.

We propose an enhanced packet access scheme for IMT-2000/UMTS random access channel (RACH). In the proposed scheme, 2-level preamble detection threshold and 2-level message transmission power are used to mitigate the power imbalance in RACH. Simulation results demonstrate that the proposed scheme improves the interference characteristics of the conventional RACH and makes wider range of the detection threshold available.

Attenuated total reflection (ATR) properties and scattered light properties were measured for Ag thin films and arachidic acid (C20) Langmuir-Blodgett (LB) ultrathin films on the Ag thin films to obtain the information about their complex dielectric constants and surface roughness utilizing an excited surface plasmon polariton. The complex dielectric constants for the Ag thin films and the C20 LB films were obtained by fitting the calculated ATR curves to the experimental ones. The surface roughnesses of these films were estimated by the angular distribution of the scattered light assuming the Gaussian function as an autocorrelation function and a linear superposition of roughness spectra. The angular spectra strongly depended on the roughness parameters: the transverse correlation length σ and the surface corrugation depth δ. The experimental angular distributions were explained by some pairs of σ and δ. It was suggested that the surface roughness of the C20 LB films changed with the number of monolayers since the angular spectra varied with the number of the C20 LB monolayers on the Ag films. It is thought that the measurement of the scattered light is useful to evaluate surface roughnesses of LB ultrathin films.

A novel method of multichannel surface EMG processing has been developed to compensate for the distortion in bipolar surface EMG signals due to the movement of innervation zones. The distortion of bipolar surface EMG signals was mathematically described as a filtering function. A compensating technique for such distorted bipolar surface EMG signals was developed for the brachial biceps during dynamic contractions in which the muscle length and tension change. The technique is based on multichannel surface EMG measurement, a method for estimating the movement of an innervation zone, and the inverse filtering technique. As a result, the distorted EMG signals were compensated and transformed into nearly identical waveforms, independent of the movement of the innervation zone.