Kentaro Taniguchi

Design and Analysis of Synthesized Template Waveform for Receiving UWB Signals

Ultra Wideband (UWB) communication system utilizing impulse signals is attractive technique which can achieve high data rate with low complexity and low power consumption. In this impulse based UWB system, lots of different shaped pulses have been considered to represent more information bits per symbol. In order to detect these different shaped UWB signals at the receiver, the synthesized template generation method using several elementary waveforms is effective. In this paper we design and analyze this synthesized template waveform instead of the conventional matched filter technique. The synthesis of UWB template waveform can be achieved as combinations of orthogonalized elementary waveforms with Fourier coefficients. By adjusting the number of elementary waveforms and their coefficients, it is possible to detect several types of UWB signals. The orders of approximation corresponding to different number of elementary waveforms are analyzed and the bit error rate properties are then investigated in AWGN and multipath fading channels. In addition, the proposed system can capture more energy by adjusting its coefficients adaptively under the multipath environment and reduce the effect of Intra-Pulse Interference (IPI) which is occurred when the propagation channel is not separable, that is, multipath components spaced closer than the typical pulse width. We show the design of the adaptive template synthesis method and its performance compared with conventional Rake receiver.

Design and analysis of template waveform for receiving UWB signals

In this paper, we propose a novel template generation method for UWB wireless communications, instead of the conventional matched filter technique. In the proposed scheme, the template waveform is constructed as combinations of orthogonalized elementary waveforms with Fourier coefficients. By adjusting the number of elementary waveforms and their coefficients, it is possible to detect several types of UWB signals. The orders of approximation corresponding to different numbers of elementary waveforms are analyzed and the bit error rate properties are then investigated by computer simulation.

Digital Baseband IC Design of OFDM PHY for a 60GHz Proximity Communication System

This paper presents a digital baseband IC design based on OFDM PHY for a 60GHz proximity communication system. We propose a low computational complexity OFDM demodulator with a carrier frequency offset estimation method in polar coordinates suitable for high-speed parallel architecture. The proposed architecture is implemented in 65nm CMOS technology, and is experimentally verified to achieve the PHY data rate above 2.2Gbps. The digital baseband IC includes a complete functionality of OFDM transceiver with error correcting codecs and MAC.

Positioning and tracking algorithm using node selection method in wireless sensor networks

For various kinds of applications in sensor network, the position information of each sensor tag is essential. Some conventional linear search algorithms used for time-of-arrival (TOA), however, are easily degraded due to serious multipath fading and non-line-of-sight (NLOS) propagation especially in indoor or urban environments. In this paper, we describe some novel algorithms for accurate indoor positioning of a sensor tag in a network of fixed base station. The proposed technique uses node selection method. The proposed algorithm has two position-fix processes. Firstly, the combination of base station in line-of-sight (LOS) environment is selected by locating the base station from the target sensor tag. Then, positioning result is obtained with only combination of base station in LOS environment. Results using simulated data show usefulness of the proposed algorithm which can achieve more robust and precise estimation compared with conventional methods.