研究者詳細 - 侯　亜飛

論文 - 侯　亜飛

分割表示 163 件中 121 - 140 件目／全件表示 >>

Fast and Low-complexity Orthogonal Matching Pursuit Based Channel Estimation in ISDB-T Receiver with 3-element ESPAR Antenna 査読

Rian Ferdian, Yafei Hou, Minoru Okada

2016 IEEE INTERNATIONAL SYMPOSIUM ON BROADBAND MULTIMEDIA SYSTEMS AND BROADCASTING (BMSB) 1 - 4 2016年

担当区分：責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

In a mobile integrated service digital broadcasting-terrestrial (ISDB-T) system, the usage of a 3-elements electrical steerable parasitic array radiator (ESPAR) antenna can be a solution to gain diversity while keeping low power consumption and compact hardware size. But, the ESPAR antenna also increases the channel estimation difficulty as the received signal from each element will interfere each others. Orthogonal matching pursuit (OMP) can become an alternative in obtaining channel information for the system with ESPAR antenna. However, the OMP technique has a drawback in huge matrix inner product in its computation. In this paper, we propose a 3-column OMP with measurement matrix strength reduction technique to reduce the complexity in the inner product computation. The propose method overall result can achieve more than 90% complexity reduction.

DOI： 10.1109/BMSB.2016.7521988

A Proposal of Half-Symbol Parallel Combinatory Multicarrier Modulation for One-Seg Service of ISDB-T System 査読

Chengbo Liu, Yafei Hou, Takeshi Higashino, Minoru Okada

2016 IEEE INTERNATIONAL SYMPOSIUM ON BROADBAND MULTIMEDIA SYSTEMS AND BROADCASTING (BMSB) 1 - 4 2016年

担当区分：責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

One-Seg service is a mobile terrestrial digital audio/video and data broadcasting service in Japan and many other countries. It transmits QPSK modulated symbols to achieve about 416 kbit/s transmission rate for mobile receivers with 428 kHz of bandwidth at UHF band. To further improve the transmission quality and spectrum efficiency, the system design must consider some major issues such as performance degradation from large Doppler shift and small size hardware for receivers which limit the system only to use low-order M-QAM modulation like BPSK or QPSK and small size of power amplifier with a low dynamic range of peak-to-average power ratio (PAPR). To reduce these impacts on the performance of One-Seg service, this paper proposes a BPSK modulated multicarrier system using parallel combinatory (PC) code. The proposed system achieves better BER performance and better PAPR characteristics with a comparable bandwidth efficiency (BWE) compared to that of the corresponding M-QAM modulated OFDM systems.

DOI： 10.1109/BMSB.2016.7521993

Diversity Gain Analysis of SFN-STBC Digital Terrestrial TV System Using Dual Polarized MIMO Antenna 査読

Ryan Paderna, Duong Quang Thang, Yafei Hou, Takeshi Higashino, Minoru Okada

2016 IEEE INTERNATIONAL SYMPOSIUM ON BROADBAND MULTIMEDIA SYSTEMS AND BROADCASTING (BMSB) 1 - 4 2016年

担当区分：責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

This paper proposes a Modified Orthogonal Matching Pursuit (MOMP)-assisted MIMO-OFDM receiver for next generation DTTV with Single Frequency Network- Space Time Block Coding (SFN-STBC). The receiver uses dual polarized antennas which can receive signals from different transmitters. In this paper, we investigate the BER performance if the transmitters transmit signals with different signal power where the receiver is in near-far effect with different receive power from different transmitter. In addition, we also examine the performance of the SFN system using MOMP for channel estimation with near-far effect. The simulation shows that the BER decreases if the received signal power from different transmitters are almost equal. And also, the MOMP BER performance is about 1 dB closer compared to ideal channel information in the range of SNR Eb/No=l5dB to Eb/No=25dB region.

DOI： 10.1109/BMSB.2016.7521981

Orthogonal Parallel Combinatory Amplitude Shift Keying Modulated Multicarrier System 査読

Chengbo Liu, Yafei Hou, Takeshi Higashino, Minoru Okada

2016 16TH INTERNATIONAL SYMPOSIUM ON COMMUNICATIONS AND INFORMATION TECHNOLOGIES (ISCIT) 7 - 10 2016年

担当区分：責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

For some scenarios where high received power cannot be guaranteed due to user moving, the OFDM system with low order M-QAM such as BPSK/QPSK is promising. This paper will propose an orthogonal parallel combinatory ASK modulated multicarrier system to achieve flexible bandwidth efficiency (BWE) using low order ASK modulation and parallel combinatory (PC) code. PC code has been shown that it can achieve flexible BWE and better peak-to-average power ratio (PAPR) performance. Our proposal will utilize PC code for both I-phase and Q-phase of frequency-domain OFDM symbol which further improve the BWE of PC-OFDM system. The proposed system can obtain better BER performance and better PAPR performance using low order ASK modulation. Therefore, the proposed system can simplify the receiver design and provide the design freedom degree with a flexible range of BWE for system design or adaptive modulation and code control.

DOI： 10.1109/ISCIT.2016.7751581

Compressed Sensing based Channel Impulse Response Estimation for Space Time Block Coding Single Frequency Network in DTV System

PADERNA Ryan, THANG Duong Quang, HOU Yafei, HIGASHINO Takeshi, OKADA Minoru

映像情報メディア学会技術報告 40 21 - 24 2016年

記述言語：英語出版者・発行元：一般社団法人映像情報メディア学会

This system uses a low complexity channel estimation for Space Time Coding in a Single Frequency Network Digital Terrestrial Television System. The receiver employs a MIMO system with vertical and horizontal antennas. The channel estimator uses a compressed sensing in time domain which exploits the sparsity of the channel impulse response. The algorithm for estimating the delay and channel gain is Orthogonal Matching Pursuit (OMP). The BER performance shows that OMP is very close to the ideal channel estimation. In addition, the OMP performance outperforms the linear interpolation method.

DOI： 10.11485/itetr.40.4.0_21

Compressed Sensing Based Channel Estimation in ISDB-T System without Cyclic Prefix

FERDIAN Rian, HOU Yafei, OKADA minoru

映像情報メディア学会技術報告 40 29 - 32 2016年

記述言語：英語出版者・発行元：一般社団法人映像情報メディア学会

Integrated Service Digital Broadcasting Terrestrial (ISDB-T) transmission system is based on OFDM technique which requires cyclic prefix (CP) and pilot tones for channel estimation. Beside data sub-carriers, the usage of CP and pilot tones occupies the ISDB-T bandwidth up to 25%. However, CP is required to mitigate the inter-symbol interference (ISI) and interblock interference (IBI) and pilot tones are required to estimate the channel response information in order to equalize the multipath effect. Recently, a wireless communication scheme without CP by using chained turbo of equalization (CHATUE) technique was proposed. Furthermore, in term of channel estimation, compressed sensing (CS) has become a prominent technique that offers better performance with less pilot tones. In this paper, we proposed a channel estimation scheme for ISDB-T system without CP using CS technique. The pilot tones are inserted at several lowest value intersections location in the previous and post symbol interferences. The final result provides an ISDB-T system with more than 90% spectrum efficiency.

DOI： 10.11485/itetr.40.4.0_29

Erratum: Quality-Based Channel Allocation Scheme with Predistortion in Multi-Channel Radio over Fiber System [IEICE Transactions on Electronics Vol. E99.C (2016) No. 5 pp. 563-573]

TANGTRONGPAIROJ Withawat, HOU Yafei, HIGASHINO Takeshi, OKADA Minoru

IEICE Transactions on Electronics 99 ( 10 ) 1226_e1 - 1226_e1 2016年

Realization of 4-by-4 MIMO Channel Using One Composite Leaky Coaxial Cable 査読

Yafei Hou, Satoshi Tsukamoto, Takahiro Maeda, Masayuki Ariyoshi, Kiyoshi Kobayashi, Tomoaki Kumagai, Atsuhiko Niwa, Fumio Suzuki, Minoru Okada

2015 12TH ANNUAL IEEE CONSUMER COMMUNICATIONS AND NETWORKING CONFERENCE 97 - 102 2015年

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Leaky coaxial cable (LCX) is widely used for wireless communication systems as an antenna for a linear-cell, which covers long and shallow areas. Since one LCX is usually utilized as one antenna, more than one LCX is required to configure a multi-input multi-output (MIMO) system. It means it is costly and space-consuming. To resolve these problems, we proposed a novel MIMO method for LCX. In this paper, we propose the method to utilize one composite cable, which consists of a pair of LCXs with different radiation characteristics, to configure a 4 x 4 MIMO channel. The measurement results confirmed that the proposed composite cable can realize a good channel condition for 4 x 4 MIMO transmission even if it is put in an anechoic chamber where no reflection path exists. On the other hand, the results also confirmed that it has good channel condition even if the spacing between a pair of LCX is as small as 2cm for the SGHz band. Therefore the proposed system can reduce the space requirement for MIMO deployment for wireless application over linear-cell environments to cope with the high rapid increase of consumer electronics devices.

DOI： 10.1109/CCNC.2015.7157953

Improved Compressed Sensing based Channel Estimation for Terrestrial DTV using Auxiliary Pilot Channel 査読

Ryan Paderna, Yafei Hou, Takeshi Higashino, Minoru Okada

2015 15TH INTERNATIONAL SYMPOSIUM ON COMMUNICATIONS AND INFORMATION TECHNOLOGIES (ISCIT) 213 - 216 2015年

担当区分：責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

This paper proposed a scattered auxiliary channel subcarriers for OFDM as additional pilots. This will improve the performance of compressed sensing based channel estimation for digital terrestrial TV. The auxiliary channel is designed to convey additional information on modulating signal transmission. The simulation shows that the proposed system has less bit-error-rate compared with the system without scattered auxiliary channel subcarriers. That is because the channel estimation will detect the correct position of the channel impulses with sufficient pilots.

DOI： 10.1109/ISCIT.2015.7458345

A Study of Capacity of 4-by-4 MIMO Channel Using Leaky Coaxial Cables for Linear-cells 査読

Sha Li, Yafei Hou, Takeshi Higashino, Minoru Okada

2015 15TH INTERNATIONAL SYMPOSIUM ON COMMUNICATIONS AND INFORMATION TECHNOLOGIES (ISCIT) 253 - 256 2015年

担当区分：責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Leaky coaxial (LCX) cable is widely used in wireless transmission communication systems as antenna for a long and narrow area called as linear-cell. We have proposed that one single LCX cable can be used as two antennas and the method to utilize one composite cable, which consists of a pair of LCXs with different radiation characteristics, to configure a multiple input and multiple-output (MIMO) system. In this paper, we will study capacity of the proposed 4-by-4 LCX-MIMO system and compare its capacity with conventional MIMO system using omnidirectional antennas over 2.4GHz band. We also investigate the capacity difference if the spacing of two LCX cable is changed over 5GHz band. The results over 2.4GHz band show that the proposed system can reduce the space requirement for MIMO deployment for wireless application over linear-cell environments. The capacity results show that proposed LCX-MIMO channel has larger capacity than that of using monopole antennas at both sides. Over 5GHz band, the proposed LCX-MIMO channel using WF allocation scheme can have the capacity near to that of independent and identically distributed (i.i.d.) channel. It has good channel capacity even if the spacing between the pair of LCXs is as small as 2cm. On the other hand, the capacity can be largely improved using the simple EP allocation scheme if the system utilize LCX cables to configure MIMO systems for both 2.4GHz and 5GHz bands.

DOI： 10.1109/ISCIT.2015.7458355

Effective VLSI Architecture for Compressed Sensing Based Channel Estimation in ISDB-T System 査読

Rian Ferdian, Yafei Hou, Minoru Okada

2015 15TH INTERNATIONAL SYMPOSIUM ON COMMUNICATIONS AND INFORMATION TECHNOLOGIES (ISCIT) 273 - 276 2015年

担当区分：責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Compressed Sensing (CS) based channel estimation has been proven to give a better reconstruction results compared to conventional method. Despite promising a better result, CS based channel estimation still suffers from high complexity computations due to huge matrix multiplication and matrix inversion operations. This paper will propose an effective CS based channel estimation VLSI architecture for ISDB-T system. Since ISDBT system is using orthogonal frequency division multiplexing (OFDM) technique for its transmission, its CS channel estimation will utilize a measurement matrix which is formed by parts of Discrete Fourier Transform (DFT) matrix. By exploiting the fact that the measurement matrix will inherit some symmetrical properties from DFT matrix, we can achieve a low complexity CS based channel estimation for practical implementation.

DOI： 10.1109/ISCIT.2015.7458360

Configuration of MIMO system using single leaky coaxial cable for linear cell environments 査読

Yafei Hou, Satoshi Tsukamoto, Takahiro Maeda, Masayuki Ariyoshi, Kiyoshi Kobayashi, Tomoaki Kumagai, Minoru Okada

IEICE COMMUNICATIONS EXPRESS 4 ( 5 ) 143 - 148 2015年

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG

It has been conventionally assumed that a single leaky coaxial (LCX) cable only is utilized as one antenna to configure a multiple-input multiple-output (MIMO) system. In this letter, we show one single LCX cable can be used as two antennas to configure a MIMO system owing to the designed intersection angle between the different radiation directivities of both input signals. The measurement results of 2 x 2 LCX-MIMO channel quality confirm that our proposed LCX-MIMO can realize a promising channel condition over 5 GHz frequency band. It also points out that the intersection angle between radiation directivities of LCX cable needs to be considered carefully to reduce the channel degradation at the both edge portions of the LCX cable.

DOI： 10.1587/comex.4.143

[Paper] ISDB-T Diversity Receiver using a 4-element ESPAR Antenna with Periodically Alternating Directivity

Reinoso Chisaguano Diego Javier, Hou Yafei, Higashino Takeshi, Okada Minoru

ITE Transactions on Media Technology and Applications 3 ( 4 ) 268 - 278 2015年

記述言語：英語出版者・発行元：一般社団法人映像情報メディア学会

Antenna diversity is one of the solutions to multipath fading but with the cost of additional hardware for every RF chain. In mobile reception application, it is difficult to install the additional antennas and cables to the vehicle due to limitations in installation cost and features. In this paper, we propose an Integrated Services Digital Broadcasting - Terrestrial (ISDB-T) diversity receiver using a 4-element electronically steerable passive array radiator (ESPAR) antenna with periodically alternating directivity. The proposed receiver obtains diversity gain requiring only a single-RF front-end and cable, thus reducing the hardware complexity compared to conventional antenna diversity receivers. The receiver utilizes compressed sensing-based channel estimation that recovers the channel state information (CSI) with good accuracy. The simulation results show that with perfect CSI, the proposed ISDB-T receiver is capable of obtaining a diversity gain of about 15 dB for a bit error rate of 10^-3.

DOI： 10.3169/mta.3.268

Introducing Dual Regularization Parameters into Regularized Channel Inversion (RCI)-Based Vector Perturbation for Modulo Loss Reduction 査読

Yafei Hou, Satoshi Tsukamoto, Kazuto Yano, Masahiro Uno, Kiyoshi Kobayashi

2014 16TH INTERNATIONAL CONFERENCE ON ADVANCED COMMUNICATION TECHNOLOGY (ICACT) 361 - + 2014年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

This paper proposes a method to reduce the symbol error caused by modulo operator for regularized channel inversion (RCI)-based vector perturbation (RCI-VP). The proposed method introduces dual regularization parameters of RCI precoding matrix. First regularization parameter alpha(1) is set so as to maximize the signal to interference plus noise ratio (SINR) value of each stream to find the optimal perturbation vector. The second regularization parameter alpha(2) is set so as to minimize the total MSE between the transmitted perturbation vector and received perturbation vector to reduce the symbol error caused by modulo operator. The simulated results confirm that the proposed method can improve the performance of RCI-VP over i.i.d. MIMO channel and frequency-selective fading MIMO channel.

Performance Comparison for 2 by 2 MIMO System Using Single Leaky Coaxial Cable over WLAN Frequency Band 査読

Yafei Hou, Satoshi Tsukamoto, Masayuki Ariyoshi, Kiyoshi Kobayashi, Tomoaki Kumagai, Minoru Okada

2014 ASIA-PACIFIC SIGNAL AND INFORMATION PROCESSING ASSOCIATION ANNUAL SUMMIT AND CONFERENCE (APSIPA) 1 - 5 2014年

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

In linear service areas such as a tunnel and along railways, leaky coaxial cable (LCX) is widely used as antenna for radio communication. Usually, one LCX is utilized as one antenna. Therefore it requires more than one LCX to configure an multi-input multi-output (MIMO) system. We have recently proposed a method that one single LCX can be utilized as two antennas by feeding different RF transmit signals to each end of the proposed cable. In this paper, we compare 2x 2 MIMO system performance using the proposed LCX and using conventional monopole antennas over 2.4GHz band for WLAN appliances. The results confirm that our proposed 2x 2 MIMO channel using a single LCX can realize a good channel condition and bit error ratio (BER) performance for MIMO transmission even within a highly correlated propagation condition. On the other hand, it also shows that the proposed LCX MIMO is promising technique for communications over linear-cell environments from the simulated results which considering the path loss and radiation pattern of LCX characteristics.

DOI： 10.1109/APSIPA.2014.7041735

An experimental evaluation of 2 × 2 MIMO system using closely-spaced leaky coaxial cables. 査読

Satoshi Tsukamoto, Takahiro Maeda, Masayuki Ariyoshi, Yafei Hou, Kiyoshi Kobayashi, Tomoaki Kumagai

Asia-Pacific Signal and Information Processing Association Annual Summit and Conference, APSIPA 2014, Chiang Mai, Thailand, December 9-12, 2014 1 - 5 2014年

4-by-4 MIMO Channel Using Two Leaky Coaxial Cables (LCXs) for Wireless Applications over Linear-cell 査読

Yafei Hou, Satoshi Tsukamoto, Masayuki Ariyoshi, Kiyoshi Kobayashi, Minoru Okadat

2014 IEEE 3RD GLOBAL CONFERENCE ON CONSUMER ELECTRONICS (GCCE) 125 - 126 2014年

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

We have recently proposed a novel 2 x 2 multipleinput multiple-output (MIMO) system that utilizes a single leaky coaxial cable (LCX) as two antennas. In this paper, we further propose a 4 x 4 MIMO system by combining two LCXs that have different radiation characteristics into one composite cable and evaluate characteristics of the channel with different spacing between the LCXs. Since the different radiation characteristics create different propagation paths, the proposed system with small spacing between LCXs can realize an efficient channel condition for 4 x 4 MIMO transmission. As a result of measurement at 2.4 GHz band, the smaller spacing as to 1 em between LCXs makes better 4 x 4 MIMO channel condition for transmission. This result indicates that the proposed system can reduce the space requirement for system deployment.

DOI： 10.1109/GCCE.2014.7031177

2 by 2 MIMO System Using Single Leaky Coaxial Cable for Linear-cells 査読

Yafei Hou, Satoshi Tsukamoto, Masayuki Ariyoshi, Kiyoshi Kobayashi, Minoru Okada

2014 IEEE 25TH ANNUAL INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR, AND MOBILE RADIO COMMUNICATION (PIMRC) 327 - 331 2014年

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Leaky coaxial cables (LCX) have been widely used as antennas to form linear service areas for radio communication systems. Such services of linear cells have been deployed inside tunnels, along railways, and so on. Usually, one LCX is utilized as one antenna. Therefore it requires more than one LCX to configure an multi-input multi-output (MIMO) system. In this paper, we propose a MIMO system using single LCX, which can be utilized as two antennas. When different RF transmit signals are fed to each end of the proposed cable, single LCX can work as two antennas. To confirm the feasibility of the proposed MIMO system, we conduct experiments to measure the characteristics of 2 x 2 MIMO channel using single LCX. The results confirm that our proposed 2 x 2 MIMO channel using single LCX can realize a good channel condition for MIMO transmission even within a highly correlated propagation condition. The proposed MIMO system using LCX will release the space requirement and reduce the cost of system for configuration of LCX MIMO system especially with large number of LCXs. It benefits the design and configuration of LCX-MIMO system for many scenarios of linear-cell.

DOI： 10.1109/PIMRC.2014.7136184

Introduction of Dual Regularization Parameters to Improve the Performance of MMSE Based Vector Perturbation 査読

Yafei Hou, Satoshi Sonobe, Satoshi Tsukamoto, Kazuto Yano, Masahiro Uno, Kiyoshi Kobayashi

2013 15TH INTERNATIONAL CONFERENCE ON ADVANCED COMMUNICATION TECHNOLOGY (ICACT) 558 - 562 2013年

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

This paper proposes a method to improve the performance of minimum-mean square error (MMSE) based vector perturbation (MMSE-VP) by introducing dual regularization parameters of MMSE precoding matrix. First regularization parameter alpha(1) is set so as to maximize the signal to interference plus noise ratio (SINR) value of each stream to find the optimal perturbation vector. The second regularization parameter alpha(2) is set as to minimize the total MSE between the transmitted perturbation vector and received perturbation vector to precancel the interference among the streams. The simulated results confirm that the proposed method can improve the performance of MMSE-VP over i.i.d. MIMO channel and indoor correlated frequency-selective fading MIMO channel.

Impact of CSI variation in subband on performance of vector perturbation based MU MIMO-OFDM system

Hou Yafei, Sonobe Satoshi, Tsukamoto Satoshi, Yano Kazuto, Uno Masahiro, Kobayashi Kiyoshi

IEICE Communications Express 2 ( 3 ) 86 - 92 2013年

記述言語：英語出版者・発行元：The Institute of Electronics, Information and Communication Engineers

Because of limitation of channel state information (CSI) feedback resource, multiuser (MU) MIMO-OFDM system usually divides all usable subcarriers into several subbands and the CSI of middle subcarrier of each subband is fed back. This feedback style generates CSI error among each subband. Due to this CSI error, a MU MIMO-OFDM system based on vector perturbation (VP) yields inefficient perturbation vectors (PVs) and mismatched spatial filters, which cause severe performance degradation. In this letter, we show that the performance degradation is mainly caused from the mismatched spatial filters rather than the inefficient PVs. This result is useful to design of a computational complexity reduction for the VP based system by reducing the matrix operations for PV search.

DOI： 10.1587/comex.2.86

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