Theoretical analysis of underwater simultaneous light Information and power transfer using inverted N parallel code shift keying with power splitting
Masao Koshimoto; Yusuke Kozawa; Hiromasa Habuchi, Corresponding, IEEE
Proceedings of IEEE International Symposium on Circuits and Systems 2023 (ISCAS 2023), 21 May 2023, [Reviewed]
Optimal FOV of Angular Diversity Receiver for Underwater Visible Light Communications
Keigo Matsunaga; Yusuke Kozawa; Hiromasa Habuchi, Corresponding, IEEE
Proceedings of IEEE International Symposium on Circuits and Systems 2023 (ISCAS 2023), 21 May 2023, [Reviewed]
Enhanced xASK-CodeSK for SLIPT
Yu Ichitsuka; Yusuke Kozawa; Hiromasa Habuchi, RISP
Proc. RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing (NCSP2023), 01 Mar. 2023, [Reviewed]
Comparison of Trilateration Method and Optical Figerprinting Method Based on OpticalWireless VN-CodeSK System
Yuta Ochiai; Daisuke Ogawa; Yusuke Kozawa; Hiromasa Habuchi, RISP
Proc. RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing (NCSP2023), 01 Mar. 2023, [Reviewed]
Non-uniform Grid-based Optical Fingerprint Positioning on VN-CSK System
Daisuke Ogawa; Yuta Ochiai; Yusuke Kozawa; Hiromasa Habuchi, RISP
Proc. RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing (NCSP2023), 01 Mar. 2023, [Reviewed]
Influence of Reflected Light in Illumination-Light VN-CodeSK Based Positioning Systems
Yuta Ochiai; Daisuke Ogawa; Yusuke Kozawa; Hiromasa Habuchi, IEICE
Proc. International Symposium on Information Theory and Its Applications (ISITA), 19 Oct. 2022, [Reviewed]
RGB-Based Secret Sharing Illumination-Light Communications With VN-CodeSK
Ryohei Hazu; Yusuke Kozawa; Hiromasa Habuchi
Proc. IEEE 11th Global Conference on Consumer Electronics (GCCE), 18 Oct. 2022, [Reviewed]
Search-Area Partitioning Approach to Optical Fingerprint Positioning System
Daisuke Ogawa; Yuta Ochiai; Yusuke Kozawa; Hiromasa Habuchi
Proc. IEEE 11th Global Conference on Consumer Electronics (GCCE), 18 Oct. 2022, [Reviewed]
Design of xASK-CodeSK System for Simultaneous Visible Light Wireless Information and Power Transfer
Yu Ichitsuka; Yusuke Kozawa; Hiromasa Habuchi
Proc. IEEE 11th Global Conference on Consumer Electronics (GCCE), 18 Oct. 2022, [Reviewed]
Chlorophyll concentration-based CSK constellation point optimization for Underwater SLIPT using Time Splitting receiver
Takuma Kogo; Yusuke Kozawa; Hiromasa Habuchi, Corresponding, IEEE
Proceedings of IEEE Global Communications Conference Workshop on Optical Wireless Communications 2020, Dec. 2020, [Reviewed]
Theoretical Analysis of Illumination-Light VN-CSK Based Equal-Weight (2, 2) VSS with MPOMS BalancerKeisuke Manaka; Liyuan Chen; Hiromasa Habuchi; Yusuke Kozawa, On an indoor illumination visible light (IVL) communication channel, the new data sharing system based on the Visual Secret Sharing (VSS) scheme has been proposed. In this paper, the theoretical formulas based on the positional relationship between the receiver and illumination apparatuses in the proposed system are derived. As a result, the relationship between the receiver position and the error rate in the indoor model under (2, 2) VSS conditions is clarified. Moreover, it is found that the error rate becomes worse as the distance between each LED and the receiver increases., Institute of Electrical and Electronics Engineers Inc.
2020 IEEE 9th Global Conference on Consumer Electronics, GCCE 2020, 13 Oct. 2020
Optimized CSK constellations for underwater SLIPT
Takuma Kogo; Yusuke Kozawa; Hiromasa Habuchi, Corresponding, RISP
Proceedings of RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing 2020 (NCSP2020), 21 Feb. 2020, [Reviewed]
Enhancement of Optical Wireless Punctured Turbo Code System in Strong Turbulence Channel
Ran Sun; Hiromasa Habuchi; Yusuke Kozawa, RISP
Proceedings of RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing 2020 (NCSP2020), 21 Feb. 2020, [Reviewed]
Optimization of Frame Synchronization System for Optical Wireless Hybrid PPM-OOK Frame Communication
Tomohiro Kiguchi; Ran Sun; Hiromasa Habuchi; Yusuke Kozawa, RISP
RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing 2020 (NCSP2020), 21 Feb. 2020, [Reviewed]
Multiple Access Capability of Einarsson Code based Optical-Wireless Code Shift Keying System
Tomofumi Haruna; Hiromasa Habuchi; Yusuke Kozawa, RISP
RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing 2020 (NCSP2020), 21 Feb. 2020, [Reviewed]
Performance Enhancement of Equal-Weight (2, 2) Visual Secret Sharing System with MPOMS on Illumination-Light VN-CSK Communication
Keisuke Manaka; Hiromasa Habuchi; Yusuke Kozawa, RISP
RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing 2020 (NCSP2020), 21 Feb. 2020, [Reviewed]
Free Space Optical Turbo Coded Communication System with Hybrid PPM-OOK Signaling
Ran Sun; Hiromasa Habuchi; Yusuke Kozawa, IEICE
IEICE transactions on fundamentals of electronics, communications and computer sciences, Jan. 2020, [Reviewed]
Theoretical Analysis of Equal-Weight (2, 2) VSS on VN-CSK Illumination Light CommunicationKeisuke Manaka; Liyuan Chen; Hiromasa Habuchi; Yusuke Kozawa, On illumination light communications, the optical-wireless transmission scheme, which combines the visual secret sharing (VSS) scheme with the variable N-parallel code-shift-keying (VN-CSK) system, has been proposed. In this paper, the error rate performances of VSS data and two specified message data is theoretical analyzed under the general condition in which the distance from one lighting apparatus is not equal with the distance from another lighting apparatus. The relationship between the error rate and the receiver position is clarified when SNR on the receiver position (length, width, height) = (2.5,2.5,0.85) [m] is 15[dB] and the dimming level $N=1$. The optimum receiver position is (2.5, 2.5, 0.85), and then BER of VSS data achieves 4.0×10-3. It is found that SNR more than 20[dB] is necessary to provide a practical use of VSS data. On the other hand, BER of the message data from LED#1 becomes a minimum value when the receiver position is (1.25,2.5,0.85). Therefore, BER of the message data is considerably superior to that of VSS data., Institute of Electrical and Electronics Engineers Inc.
2019 29th International Telecommunication Networks and Applications Conference, ITNAC 2019, 01 Nov. 2019
Frame Synchronization Performance of Optical-Wireless Hybrid BPPM-OOK SystemTomohiro Kiguchi; Ran Sun; Hiromasa Habuchi; Yusuke Kozawa, Turbo code can be closed to the Shanon limit and is expected to be used for reliable applications. The optical-wireless turbo coded system with a hybrid BPPM-OOK is superior to those using other pulse modulation schemes in bit error rate performance. To realize the optical-wireless turbo coded system with hybrid BPPM-OOK demands the implementation of frame synchronization schemes. The frame synchronization scheme for the turbo coded system with hybrid BPPM-OOK are proposed. The scheme is focused on the frame structure which consists of two slots for BPPM and two slots for OOK. The detection probability of frame timing signal and the average false alarm probability are evaluated. However, it is difficult to optimize the number of stages on the racing counters. In this paper, the retention time and the recovery time are evaluated to derive the optimization of the stages of racing counters in the frame synchronization system. As a result, it is found that the optimum number of stages on racing counters varies according to required recovery time., Institute of Electrical and Electronics Engineers Inc.
2019 29th International Telecommunication Networks and Applications Conference, ITNAC 2019, 01 Nov. 2019
Inverse Pulse Position Modulation Scheme for Underwater Visible Light Simultaneous Wireless Information and Power Transfer
Yusuke Kozawa; Ryota Kimoto; Yohtaro Umeda, Lead
The 1st Optical wireless and Fiber Power Transmission Conference (OWPT2019) in Optics and Photonics International Congress, Apr. 2019, [Reviewed]
Underwater Visible Light Simultaneous Wireless Information and Power Transfer using Inverse Pulse Position Modulation Scheme
Ryota Kimoto; Yusuke Kozawa; Yohtaro Umeda; Hiromasa Habuchi
Proceedings of the RISP International Workshop on Nonlinear Circuits, Communication and Signal Processing, 05 Mar. 2019, [Reviewed]
High Accuracy Positioning System on Indoor Optical Wireless VN-CSK System
Hikari Iizuka; Ran Sun; Hiromasa Habuchi; Yusuke Kozawa
Proceedings of the RISP International Workshop on Nonlinear Circuits, Communication and Signal Processing, 05 Mar. 2019, [Reviewed]
Effective Frame Error Detecting Scheme for Optical-Wireless Advanced Framed-DOOK System
Yuta Asano; Hiromasa Habuchi; Yusuke Kozawa
Proceedings of the RISP International Workshop on Nonlinear Circuits, Communication and Signal Processing, 05 Mar. 2019, [Reviewed]
Channel capacity of hybrid dimmable MPPM for visible light communications
Takashi Ozaki; Yusuke Kozawa; Yohtaro Umeda, In this paper, variable multi-pulse pulse position modulation (VMPPM) that combines a new dimming control method using pseudo-orthogonal codes with MPPM is proposed. Proposed VMPPM can improve the channel capacity of conventional variable rate MPPM (VR-MPPM) because new dimming control method can reduce degradation of the error rate performance. In VMPPM, r slots are selected from n MPPM slots and codes for data are generated in each selected r slot according to source data [log2 (nr )]+ r [bit/frame]. Additionally, VMPPM can represent the dimming percentage of n − r + 1 stages by using the empty n−r slots. Moreover, we have presented hybrid dimmable MPPM (HD-MPPM) that combines proposed VMPPM with VR-MPPM to enhance the channel capacity of VR-MPPM. In this paper, the channel capacity of HD-MPPM is investigated through theoretical analysis. In addition, the channel capacity of HD-MPPM is compared with that of VR-MPPM by taking into account the human eye response. Consequently, HD-MPPM can enhance the channel capacity of VR-MPPM at the high dimming percentage. Especially, when the ratio of electrical signal power per bit to noise is 0 dB and -5 dB, HD-MPPM can improve the channel capacity about 15 [bit/channel use] and about 20 [bit/channel use], respectively, at the perceived light is 80%., VDE Verlag GmbH
SCC 2015 - 10th International ITG Conference on Systems, Communications and Coding, 2019
Theoretical Analysis on Bit Error Rate of Visible-Light Variable N-parallel Code-Shift-Keying
Keisuke Ohsawa; Hiromasa Habuchi; Yusuke Kozawa
IEICE transactions on fundamentals of electronics, communications and computer sciences, Dec. 2018, [Reviewed]
Proposal of Optical Wireless Turbo Coded System with Hybrid PPM-OOK Signaling
Ran Sun ; Hiromasa Habuchi ; Yusuke Kozawa, IEEE
Proceedings of IEEE 2018 12th International Conference on Signal Processing and Communication Systems (ICSPCS), Dec. 2018, [Reviewed]
Frame Error Detection Performance of Optical-Wireless Advanced Framed-DOOK System
Yuta Asano ; Hiromasa Habuchi ; Yusuke Kozawa, IEEE
Proceedings of IEEE 2018 12th International Conference on Signal Processing and Communication Systems (ICSPCS), Dec. 2018, [Reviewed]
Enhanced On-demand WSN in terms of MC-CDMA with MPOMS
Yutaka Imaizumi; Hiromasa Habuchi; Yusuke Kozawa, IEEE
Proceedings of IEEE International Symposium on Intelligent Signal Processing and Communication Systems, 28 Nov. 2018, [Reviewed]
Exact Bit Error Rate Analysis for Optical-Wireless Framed-DOOK System
Yuto Asano; Hiromasa Habuchi; and Yusuke Kozawa, IEEE
Proceedings of IEEE 7th Global Conference of Consumer Electronics, 12 Oct. 2018, [Reviewed]
BER Performance Impaired by Transmission Time Offset Between Users in Optical Wireless CSK/ACDMA System Using DMPOMs
Takashi Tokunaga; Hiromasa Habuchi; Yusuke Kozawa; and Ran Sun, IEEE
Proceedings of IEEE 7th Global Conference of Consumer Electronics, 12 Oct. 2018, [Reviewed]
Proposal of VN-CSK System having Positioning Function
Hikari Iiduka; Hiromasa Habuchi; and Yusuke Kozawa, IEEE
Proceedings of IEEE Vehicular Technology Society Asia Pacific Wireless Communications Symposium, 22 Aug. 2018, [Reviewed]
Theoretical Analysis of Optical-Wireless Code Shift Keying System using Extended Einarsson Code
Tomofumi Haruna; Hiromasa Habuchi; and Yusuke Kozawa, IEEE
Proceedings of IEEE Vehicular Technology Society Asia Pacific Wireless Communications Symposium, 22 Aug. 2018, [Reviewed]
Design of Synchronization Signal Embedded Optical Wireless Differential OOK
Yuta Asano; Hiromasa Habuchi; Yusuke Kozawa, Visible Light Communications Association
Proceedings of 2nd International Conference and Exhibition on Visible Light Communications, 16 Mar. 2018, [Reviewed]
Performance Evaluation of Hybrid VN-CSK/PAM for Lighting Constrained Visible Light Communications
Keisuke Osawa; Hiromasa Habuchi; Yusuke Kozawa
Proceedings of the RISP International Workshop on Nonlinear Circuits, Communication and Signal Processing, 06 Mar. 2018, [Reviewed]
Error Correcting Codes in Underwater RGB-LED Parallel Communication: Turbo or LDPC?
San Sun; Hiromasa Habuchi; Yusuke Kozawa
Proceedings of the RISP International Workshop on Nonlinear Circuits, Communication and Signal Processing, 06 Mar. 2018, [Reviewed]
A quadrature-modulation EPWM transmitter that uses sine wave carriers for i and Q channel with a 90° hybridTomoaki Morita; Ryo Sakai; Yohtaro Umeda; Yusuke Kozawa, Quadrature-modulation (QM) envelope-pulse-width modulation (EPWM) transmitter with a 180° hybrid as a power combiner has been proposed to suppress the switching loss due to the breaking of zero-current switching (ZCS) condition and, therefore, to increase the power efficiency. However, we found that the ZCS condition breaking still remains in I-channel of this transmitter. As a result, the power efficiency for I-ch decreases. To solve this problem we propose a QM-EPWM transmitter that uses sine-wave carriers for both I- and Q-channel with a 90° hybrid in this paper. The proposed transmitter eliminates the remaining switching loss due to the phase shift of the carrier in I-channel and increase the power efficiency. The increase in power efficiency of the proposed transmitter from the previous one is evaluated by computer simulation., Institute of Electrical and Electronics Engineers Inc.
Asia-Pacific Microwave Conference Proceedings, APMC, 08 Jan. 2018,
[Reviewed] Hybrid PWM/DPAM Dimming Control for Digital Color Shift Keying Using RGB-LED ArrayJumpei Okumura; Yusuke Kozawa; Yohtaro Umeda; Hiromasa Habuchi, As a method of dimming support for visible light communications using a massive LED array, we consider a hybrid pulse width modulation/digitally controlled pulse amplitude modulation (PWM/DPAM) system. Especially, in this paper, we consider a digital color shift keying (DCSK) using an RGB-LED array as an optical intensity modulation scheme, that transmits data through the ratio of the optical intensities (i.e., color) emitted by red, green, and blue LEDs. In DCSK, since only one color is activated in each RGB-LED at a time, the color can be represented by the combination of the digitally (i.e., linearly) controlled 'ON-OFF' LEDs. In general, for the dimming control system of DCSK, two schemes have been considered. One is the dimming control by PWM, which changes the duty cycle of optical transmit signals, and the other is the dimming control by DPAM, which changes the number of active LEDs in the RGB-LED array. In this paper, PWM and DPAM are combined to realize a higher spectral efficiency than PWM and a wider dimming range than DPAM. We evaluate the error performances of the proposed system, DCSK with PWM, and DCSK with DPAM from a simulation analysis under several measured light dimming levels. The results show that DPAM should be used only for low bit rate systems because the effect of inter-symbol-interference (ISI), caused by the LED frequency response, increases at a high bit rate. While, PWM is significantly robust against ISI because the PWM signal duration is limited in a symbol duration at the low dimming levels and the empty duration can mitigate the effect of ISI even if the bit rate is high. When focusing on symbol error rate performances corresponding to the dimming levels, the hybrid dimming control and the PWM dimming control can achieve lower signal energy-to-noise-ratio at the dimming level of low and high, respectively., Institute of Electrical and Electronics Engineers Inc.
IEEE Journal on Selected Areas in Communications, 01 Jan. 2018,
[Reviewed] Improved synchronization scheme for indoor visible-light differential on-off keyingYuta Asano; Hiromasa Habuchi; Yusuke Kozawa, In this paper, as binary modulation schemes, the differential on-off keying (DOOK) system, which can achieve anti-background noise capability and high data transmission efficiency, is considered. In order to solve the synchronization slip, a visible-light framed DOOK system embedding {-1,+1}-synchronization signal pattern is proposed. Moreover, theoretical formulas of detection and false alarm probability are derived. The detection probability taking into account false rate is evaluated under the visible-light channel with scintillation and background noise. Consequently, in the evaluation of detection probability taking into account false alarm rate, the proposed system is better than the conventional system., Institute of Electrical and Electronics Engineers Inc.
2017 IEEE 6th Global Conference on Consumer Electronics, GCCE 2017, 19 Dec. 2017,
[Reviewed] Inverse pulse position modulation schemes for simultaneous visible light wireless information and power transferRyota Kimoto; Yusuke Kozawa; Yohtaro Umeda; Hiromasa Habuchi, In this paper, for constructing flexible underwater wireless sensor network, we discussed an underwater visible light communication system with simultaneous power transfer. For realizing the system, the received optical power is used for both data communication and power transfer, and it is necessary to design the receiver for separating the signal to alternate current (AC) and direct current (DC). We employ the receiver circuit based on low pass filter for DC signal and high pass fileter for AC signal. Moreover, we analyzed the BER performance and power supply performance when the designed AC/DC separation filter is based solar panel is used as the receiver. As a modulation scheme, we consider inverse pulse position modulation (IPPM) which would achieve stable supply of power. As a result, in the BER performances, IPPM show the higher performances compared to OOK. Compared to PPM, the performances for IPPM deteriorated by about 4.78 dB due to the high transmitted power per bit. However, the high transmitted power per bit is important for power supply, and PPM and IPPM show similar BER performances when the same pulse amplitudes of these modulation schemes. In the CV performances, CV of IPPM is improved by 20% compared to OOK and 1.1% compared to PPM with the bit rate of 200 kbps. From these results, IPPM can achieve stable supply of power., Institute of Electrical and Electronics Engineers Inc.
2017 27th International Telecommunication Networks and Applications Conference, ITNAC 2017, 15 Dec. 2017,
[Reviewed] SCDMA capability of high-density code-shift keying using dual MPOMs in optical-wireless channelTakashi Tokunaga; Hiromasa Habuchi; Yusuke Kozawa; Ran Sun, The high density code-shift-keying (CSK) using Pseudo Noise (PN) codes generated by combining modified pseudo orthogonal M-sequence sets (MPOMs) with biorthogonal code has been proposed. In this paper, synchronous code division multiple access (SCDMA) capability of the proposed system is clarified under the optical-wireless channel. Consequently, simulation results are in good agreement with theoretical calculation results. In the proposed system, it is found that the performance deterioration is considerably small when the number of users ≦ 3. Moreover, the proposed system remarkably outperforms the conventional system when the number of users ≧ 2., Institute of Electrical and Electronics Engineers Inc.
2017 27th International Telecommunication Networks and Applications Conference, ITNAC 2017, 15 Dec. 2017,
[Reviewed] Proposal of optical wireless turbo coded APPM systemRan Sun; Hiromasa Habuchi; Yusuke Kozawa, In optical wireless communications, because of the attenuation of light and the shadowing of the channel, partial erasure channel, which means failing to receive a part of transmitted light steams, may raise. It is of importance to design a system compatible with partial erasure channel. In this paper, a new turbo coded APPM system is proposed. APPM is a modulation technique combining with amplitude-shift keying and binary pulse position modulation. The bit error rate (BER) performances of the proposed system is evaluated through computer simulation in both optical-wireless standard channel and partial erasure channel. Moreover, the BER performance is compared with the conventional punctured turbo coded binary pulse position modulation system. As results, in standard channel, the proposed system shows the same BER performance as the conventional system. In partial erasure channel, the proposed system outperforms the conventional system far., Institute of Electrical and Electronics Engineers Inc.
2017 27th International Telecommunication Networks and Applications Conference, ITNAC 2017, 15 Dec. 2017,
[Reviewed] A theoretical analysis of visible-light variable N-parallel code-shift-keying in LOS indoor environmentsKeisuke Osawa; Hiromasa Habuchi; Yusuke Kozawa, Indoor visible light communications utilizing LED light that are available for not only the illumination but also data transmission are received interest for future home networks. The dimming control function which the illumination brightness can be controlled should not be compromised by the data transmission function. The bit error rate performance of the indoor visible light communications deteriorates by co-channel interference from neighboring LEDs. The Variable N-parallel Code-Shift-Keying (VN-CSK) system using the Modified Prime Sequence Codes (MPSC) has been proposed for indoor visible light communications. The VN-CSK system using MPSC has not only a suppression function for reducing co-channel interference from neighboring LEDs, but also a function for keeping constant data transmission efficiency regardless of dimming control. In this paper, the bit error rate performance of the VN-CSK system using MPSC is evaluated under the indoor visible light communication channel by theoretical analysis. As a result, under the indoor visible light communication channel, the VN-CSK system using MPSC can suppress the influence of co-channel interference by using the group characteristics of MPSC., Institute of Electrical and Electronics Engineers Inc.
2017 8th International Workshop on Signal Design and Its Applications in Communications, IWSDA 2017, 03 Nov. 2017,
[Reviewed] New two-layered pseudo-noise code for optical-wireless code-shift keying/SCDMATakashi Tokunaga; Hiromasa Habuchi; Yusuke Kozawa, In this paper, a design of two-layered pseudonoise (PN) code for optical-wireless code-shift keying (CSK) is considered. One of the important issues encountered in optical-wireless CSK systems is to design a PN code for enhancing code division multiple access (CDMA) capability and a ratio N/L between the number of codes (N) and the PN code length (L). In this paper, a CSK system using two-layered PN codes which consist of outer-codes with Lo chips and inner-codes with LI chips is proposed. Since the receiver of the proposed system can use the two-step demodulation scheme, it is expected that the proposed system suppress the performance degradation caused by co-channel interference. Consequently, N/L of the proposed system achieves more than 1. Moreover, when the length of the inner code is L/ and the length of outer code is LO, the proposed system can accommodate N/-1 users without co-channel interference in synchronous CDMA., Institute of Electrical and Electronics Engineers Inc.
2017 8th International Workshop on Signal Design and Its Applications in Communications, IWSDA 2017, 03 Nov. 2017,
[Reviewed] Impact of framed-DOOK optical wireless system using error correcting codesRan Sun; Hiromasa Habuchi; Yusuke Kozawa, For reducing the influence of background noise and inhibiting synchronization slip in optical wireless communication, framed-differential on-off keying (Framed-DOOK) modulation scheme has been proposed. In this paper, the Framed-DOOK is combined with error correcting codes. The bit error rates of Framed-DOOK system using both standard turbo code and regular low density parity check (LDPC) code are evaluated by computer simulation taking the background noise and scintillation into account. The simulation results are compared focusing on the effect of background noise reduction, for investigating which code is suitable for the Framed-DOOK modulation scheme. Likewise, the comparison of the bit error rate performances between the proposed Framed-DOOK system and the conventional on-off keying (OOK) system is presented. In conclusion, with-45.0 [dBm] background noise, the Framed-DOOK system using both standard turbo code and regular LDPC code is able to get a 4 [dB] enhancement than the conventional OOK system. Moreover, it is confirmed that at the effect of background noise reduction, the Framed-DOOK system using standard turbo code is better than the system using LDPC code, when transmitting a short block length (256[bits]) code., Institute of Electrical and Electronics Engineers Inc.
2017 8th International Workshop on Signal Design and Its Applications in Communications, IWSDA 2017, 03 Nov. 2017,
[Reviewed] Quadrature-modulation envelope-pulse-width-modulation transmission system using quadrature polarized wavesRyo Sakai; Tomoaki Mgrita; Yohtaro Umeda; Yusuke Kozawa, This paper presents a quantitative evaluation of the power efficiency decrease obtained by breaking the zero-current switching (ZCS) condition due to the alternate output occurring in a bi-level quadrature-modulation (QM) envelope-pulse-width-modulation (EPWM) transmitter. The power efficiency is evaluated by changing the Q factor of the series resonance circuit inserted in a power amplifier (PA). As a result, the power efficiency that includes signal and quantization noise rapidly decreases with increasing Q factor. Consequently, the power efficiency for the signal only becomes low. Therefore, a QM EPWM transmission system using quadrature polarized waves is proposed to satisfy the ZCS condition for high efficiency. A digital signal processing and microwave circuit simulation shows that the proposed transmission system can demodulate both sigma and delta components and improves the power efficiency of the PAs., Institute of Electrical and Electronics Engineers Inc.
Midwest Symposium on Circuits and Systems, 27 Sep. 2017,
[Reviewed] Underwater Turbo-code optical communication system compatible with partial erasure channelRan Sun; Hiromasa Habuchi; Yusuke Kozawa, In this paper, a novel underwater Turbo-code optical communication system compatible with partial erasure channel is proposed. A scheme re-arranging the parity bits of Turbo-code is used for preventing the degradation of communication performance in partial erasure channel. Unequal Transmission Power Allocation (UTPA), a technique which allocate different powers to information bits and parity bits keeping the total transmission power fixed, is applied for enhancement of the proposed system. Binary Pulse Position Modulation (BPPM) is used as the modulation technique. The bit error rate (BER) performances of the proposed system are evaluated through computer simulation both in general underwater channel and the special situation: partial erasure channel., Institute of Electrical and Electronics Engineers Inc.
IEEE Region 10 Annual International Conference, Proceedings/TENCON, 08 Feb. 2017,
[Reviewed] Performance evaluation of multiuser digital color shift keying using pseudo-noise code with on-off signalingFuminori Sato; Yusuke Kozawa; Yohtaro Umeda, In this paper, a digital color shift keying with code division multiplexing (DCSK/CDM) is proposed as a multiple access technique in visible light communications. Multiple multicolor LEDs were used in DCSK/CDM where only one color is activated in each multicolor LED at a single time. Therefore the information is encoded in the combinations of activated colors. The main advantage of DCSK/CDM over conventional CSK/CDM is avoiding the need of any digital-to-analog converters. Moreover, two type of pseudo noise codes for DCSK/CDM were considered
generalized modified prime sequence code (GMPSC) and Hadamard code with on-off signaling (HC). In particular, DCSK/CDM with HC improves the data transmission rate by employing sequence inversion keying (SIK) technique. In this paper, the symbol error rate (SER) and bit error rate (BER) performance of the DCSK/CDM systems using multiple RGB-LEDs (i.e., TLED: trichromatic LED) are evaluated through theoretical analysis in the multi-user case. It is shown that BER of DCSK/SIK can be improved by about 1 dBm compared with the DCSK/DS systems when the spectral efficiency over VLC network is 1.3 bit/sec/Hz. In addition, when the spectral efficiency per TLED is the same as 0.063 bit/sec/Hz/LED., Institute of Electrical and Electronics Engineers Inc.
Proceedings - 2016 4th International Symposium on Computing and Networking, CANDAR 2016, 13 Jan. 2017,
[Reviewed] Cyclic Mapping Method for Digital Color Shift Keying with RGB-LED ArrayYusuke Matsuda; Yusuke Kozawa; Yohtaro Umeda, Digital color shift keying (DCSK) is a visible light communication (VLC) intensity modulation method, which can fulfill the both roles of lighting and communication. DCSK transmits data through an intensity ratio of red, green, and blue (RGB), which can be represented by digital "on-off" LED control by multiple RGB-LEDs (i.e., RGB-LED array). Moreover, a perceived color on human eye (i.e., target color) of modulated optical signal can be shifted by M constellation points for M-ary DCSK. However, color deviation over RGB-LED array face is caused by a fixed mapping of lighted LEDs corresponding to each DCSK symbol. In this paper, we consider cyclic mapping method for the target color controlled DCSK system to mitigate the color deviation of RGB-LED array face. Moreover, we experimentally evaluate the DCSK light signal by correlated color temperature (CCT) and error vector magnitude (EVM) performance. As a result, the CCT performance of DCSK system with cyclic mapping can be improved when the desired CCT of the target color is 3000K, 4000K, or 5700K. While, the DCSK system with cyclic mapping method can achieve similar EVM performance of the conventional DCSK system., IEEE
2017 IEEE RADIO AND WIRELESS SYMPOSIUM (RWS), 2017,
[Reviewed] Turbo-code Optical Communication System Compatible with Partial Erasure Channel
Ran Sun; Hiromasa Habuchi; Yusuke Kozawa
Proceeding of Premier International Technical Conference of IEEE Region 10, 24 Nov. 2016, [Reviewed]
Enhancement of RGB Parallel Turbo-code System with UTPA in Optical Partial Erasure Channel
Ran Sun; Hiromasa Habuchi; Yusuke Kozawa
Proceeding of 13th 2016 IEEE Vehicular Technology Society Asia Pacific Wireless Communications Symposium (APWCS2016), 26 Aug. 2016, [Reviewed]
Digital Color Shift Keying With Multicolor LED ArrayNaoya Murata; Yusuke Kozawa; Yohtaro Umeda, Color shift keying (CSK) is a visible light communication (VLC) intensity modulation scheme, which is outlined in IEEE 802.15.7, that transmits data imperceptibly through the variation of the color emitted by red, green, and blue light-emitting diodes (RGB LEDs). In this paper, digital CSK (DCSK) is presented, which represents CSK symbols by digitally controlled multiple multicolor LEDs to avoid the effect of LED nonlinearity. By using this scheme, the DCSK system using nine RGB LEDs can transmit IEEE 802. 15.7 CSK constellations with an error-vector-magnitude (EVM) performance on an x - y chromaticity of 3%. The bit-error-rate (BER) evaluation of both the conventional and the proposed DCSK system shows that the DCSK system achieves similar BER to that of CSK with a linear variable current driver including predistortion, with taking into account optical wireless channels including the LED response, undesired color shift, and channel crosstalk by the practice characteristics of RGB LEDs, RGB bandpass filters, and photodiodes., IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
IEEE PHOTONICS JOURNAL, Aug. 2016,
[Reviewed] Optimization of DSM Sampling Frequency and Interleaving Frequency for Bilevel Quadrature-Modulation EPWM TransmitterTakashi Noda; Yohtaro Umeda; Yusuke Kozawa, We previously proposed a bilevel quadrature-modulation (QM) envelope-pulse-width-modulation (EPWM) transmitter using half a side of a trilevel EPWM architecture. However, the optimum relationship between the ΔΣ modulation (DSM) sampling frequency (fs), the interleaving frequency (fi) and the carrier frequency (fc) for a bilevel QM EPWM transmitter has not been investigated. This paper presents this optimum relationship, with the error vector magnitude (EVM) and the coding efficiency (CE) as figures of merit (FOMs)., 信号処理学会
Journal of Signal Processing, 25 Jul. 2016,
[Reviewed] Robust Turbo-Coded OOK System for Background Noise Alleviation and Frame Synchronization in Optical Wireless ChannelYuto Matsuda; Hiromasa Habuchi; Yusuke Kozawa, In this paper, optical wireless turbo-coded on-off-keying (OOK) systems have been investigated. These systems suffer from performance deterioration due to background noise and the occurrence of synchronization slip. To solve these problems, an optical wireless system that combines a framed differential OOK (framed-DOOK) system and a punctured turbo-coded system is proposed. The bit error rate (BER) performance ef the punctured turbo-coded framed-DOOK system is evaluated in an optical wireless channel. It is shown that the punctured turbo-coded framed-DOOK system can greatly improve the BER performance of the conventional punctured turbo-coded OOK system. Moreover, in the framed-DOOK systems, the BER of the punctured turbo-coded system is almost the same as that of the standard turbo-coded system. Therefore, the proposed punctured turbo-coded framed-DOOK system is more attractive than the conventional turbo-coded OOK systems for optical wireless communications., 信号処理学会
Journal of Signal Processing, 25 Jul. 2016,
[Reviewed] Differential-OOK System for Underwater Visible-Light CommunicationsSaotome Mitsuru; Kozawa Yusuke; Umeda Yohtaro; Habuchi Hiromasa, Corresponding, Underwater wireless optical communication (UWOC) can provide higher-data-rate communication over moderate distances for new underwater applications. However, high-speed data transmission in UWOC is mainly limited by spectral attenuation in water and background noise. In this study, we propose an analytical underwater daylight noise model that incorporates the daylight simulation model SPCTRAL2 with an upwelling solar radiance model for the practical analysis of background light for UWOC. Moreover, we also consider a differential on-off-keying (DOOK) system in our simulation model. This DOOK system was proposed to reduce the effect of background noise in free-space optical communications. It was found that the effectiveness of the DOOK system can be verified by our new underwater daylight noise model. For example, for coastal water and harbor water, the DOOK system can improve BERs compared with an OOK system with a fixed threshold. In addition, the DOOK system can achieve a BER of less than10
−6 in coastal water during daylight hours., 信号処理学会
Journal of Signal Processing, 25 Jul. 2016,
[Reviewed] Improved Code-Shift Keying Systems with Functional Pseudonoise Code in Optical-Wireless ChannelShota Takayanagi; Hiromasa Habuchi; Yusuke Takamaru; Yusuke Kozawa, In this paper, improved code-shift keying (CSK) systems with a functional pseudonoise (PN) code are considered for use in indoor optical-wireless channels. In CSK, increasing the number of optical PN codes improves the data rate. It is also effective for increasing the number of simultaneously transmitting optical PN codes. This method is named N-parallel CSK (N-CSK), which indicates the transmission of N codes. In order to enhance the data rate of CSK systems, optical PN code design has become one of the key areas of study. As such functional codes, in this paper we consider EPOM and POEPC, which can be generated by fusing two kinds of optical PN codes. CSK systems can implement two-stage demodulation, which demodulates every optical PN code. It is expected that two-stage demodulation will improve the bit error rate (BER) performance of CSK systems. In this paper, we combine two-stage demodulation with CSK systems: CSK using EPOM and N-CSK using POEPC. It was found that the BER of CSK systems can be improved by utilizing two-stage demodulation., 信号処理学会
Journal of Signal Processing, 25 Jul. 2016,
[Reviewed] Novel Parallel Optical Turbo-code Communication System using RGB LEDs for Partial Erasure Channel
Ran Sun; Hiromasa Habuchi; Yusuke Kozawa
The 31st International Technical Conference on Circuits/Systems, Computers and Communications (ITC-CSCC 2016), 13 Jul. 2016, [Reviewed]
Proposal of a Variable N-CSK with MPSC for an Intellectual Illumination Light Data Transmission System
Keisuke Osawa; Hiromasa Habuchi; Yusuke Kozawa
The 31st International Technical Conference on Circuits/Systems, Computers and Communications (ITC-CSCC 2016), 13 Jul. 2016, [Reviewed]
Impact of improved on-off-keyed turbo-code system in optical wireless channel
Yuto Matsuda; Hiromasa Habuchi; Yusuke Kozawa, NCSP
Proceeding of 2016 RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing (NCSP'16), 08 Mar. 2016, [Reviewed]
Data-rate-enhanced optical-wireless code-shift-keying system having two-stage demodulation
Shota Takayanagi; Hiromasa Habuchi; Yusuke Takamaru; Yusuke Kozawa, NCSP
Proceeding of 2016 RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing (NCSP'16), 07 Mar. 2016, [Reviewed]
Rigorous symbol error rate analysis of hierarchical MPPM-CNK through optical wireless channel
Atsuhiro Takahashi; Hiromasa Habuchi; Yusuke Kozawa, NCSP
Proceeding of 2016 RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing (NCSP'16), 07 Mar. 2016, [Reviewed]
BER performance of digital color shift keying with target color controlShunsuke Igata; Yusuke Kozawa; Yohtaro Umeda; Hiromasa Habuchi, In this paper, target color control for digital color shift keying (DCSK) with multiple multicolor LEDs is presented for improving illumination performances of the modulated DCSK signal. This DCSK system using multiple multicolor LEDs can represent the conventional multi-level CSK symbol with the total amount of each non-varying 'On-Off' intensity of multiple LEDs. This paper analyzes the illumination and communication performances of DCSK signals, including correlated color temperature (CCT), color tolerance, color rendering index (CRI), and bit error rate (BER). In particular, the BER performances of the DCSK constellations points, which achieve CCT = 3000K, 5000K, and 6500K, are evaluated from theoretical analysis under the conditions of total optical power or total luminous flux is constant for flicker mitigation. Consequently, the CRI performances can be increased when the number of Quad LEDs (QLEDs) increases. Moreover, it can be seen that the BER performance of DCSK with desired CCT of 5000K is better than those of 3000K and 6500K., Institute of Electrical and Electronics Engineers Inc.
2016, 10th International Conference on Signal Processing and Communication Systems, ICSPCS 2016 - Proceedings, 2016,
[Reviewed] Theoretical Analysis of Visible-Light Code-Shift Keying Using Extended Pseudo-Orthogonal M-sequence in Line-of-Sight LinkShota Takayanagi; Hiromasa Habuchi; Yusuke Kozawa, In this paper, visible-light code-shift keying (CSK) systems using the extended pseudo-orthogonal M-sequence (EPOM) are analyzed in line-of-sight (LOS) link. In particular, the bit error rate (BER) characteristics and the influence of interference from ambient light-emitting diodes (LEDs) are clarified by theoretical analysis. In consideration of N/L which is the ratio between the number of codes.. and code lengthN/L of EPOM is L/4 times as large as that of the conventional optical pseudonoise (PN) codes such as the pseudo-orthogonal extended prime sequence code set (POEPC). Therefore, the CSK systems using EPOM have higher information transmission efficiency than the CSK systems using the conventional optical PN codes. In this paper, the BERs of visible-light CSK using EPOM and visible-light CSK using POEPC are evaluated under the same information transmission efficiency in LOS link. As a result, the BERs of the CSK systems using EPOM is lower than that of the CSK systems using POEPC even though there is the influence of the ambient light., IEEE
2016 10TH INTERNATIONAL CONFERENCE ON SIGNAL PROCESSING AND COMMUNICATION SYSTEMS (ICSPCS), 2016,
[Reviewed] Performance evaluation of novel optical-wireless variable N-parallel code-shift-keyingKeisuke Osawa; Hiromasa Habuchi; Yusuke Kozawa, The indoor visible light communications have mainly the two serious problems
the bit error rate (BER) deterioration due to interference from ambient light and change of the data transmission efficiency according to dimming level. To settle the above problems, in this paper, the variable N-parallel code-shift-keying (VN-CSK) system with modified prime sequence codes (MPSC) for indoor visible light communications is considered. The VN-CSK system with MPSC achieves the same transmission efficiency by changing the number of the codes to select from M MPSCs depending on light regulation data. For example, if the number of MPSC is 5, the VN-CSK system with MPSC can realize 4 stages of dimming level. Moreover, the VN-CSK system with MPSC can suppress the influence of co-channel interference by using the group characteristics of MPSC. The bit error rate performance of the VN-CSK system with MPSC is evaluated in optical wireless channel by theoretical analysis. The VN-CSK system with MPSC can realize BER 10-6 when average received optical power per code is -49 [dBm] and the desired signal to interference signal ratio Pw/Pi ≥ 3 [dB]., Institute of Electrical and Electronics Engineers Inc.
2016, 10th International Conference on Signal Processing and Communication Systems, ICSPCS 2016 - Proceedings, 2016,
[Reviewed] Proposal of Turbo-Coded Differential OOK for Optical IM/DD System
Sachin Rai; Yusuke Kozawa; Hiromasa Habuchi; Yuto Matsuda
Proceeding of 2015 RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing (NCSP2015), Mar. 2015, [Reviewed]
An Experimental Evaluation on EVM Performance for 4-CSK(Color Shift Keying) using visible light with multiple Full-color LEDsHiroki Shimamoto; Yusuke Kozawa; Yohtaro Umeda, Color Shift Keying (CSK) is a modulation method for visible light communications, which transmit information through three-band light of multi-color light source, outlined IEEE 802.15.7. In this paper, new CSK system using multiple full-color LEDs is proposed for realizing non-variable LED current control. Moreover, error vector magnitude (EVM) performance of the proposed system is demonstrated and evaluated. Consequently, when the distance between the plane of the LEDs and PD is larger than 12cm, the EVM performance of the proposed CSK is almost identical with that of the conventional CSK., IEEE
2015 IEEE RADIO AND WIRELESS SYMPOSIUM (RWS), 2015,
[Reviewed] Bi-level Quadrature-modulation Low-pass EPWM transmitter Using Half Side of Tri-level Delta Sigma ModulatorTakashi Noda; Wataru Someya; Yoshiharu Iikura; Yohtaro Umeda; Yusuke Kozawa, This paper presents a bi-level quadrature-modulation (QM) low-pass (LP) envelope-pulse-width-modulation (EPWM) transmitter using a half side of tri-level EPWM. Simulation including digital signal processing with the QM LP-EPWM and microwave circuit simulation with a class-D power amplifier (PA) using n-MOSFETs shows an excellent error vector magnitude (EVM) of 36 dB at 1 GHz. The transmitter with a class-D PA for bi-level EPWM signal shows much better EVM performance than the one for trilevel signal., IEEE
2015 IEEE Topical Conference on Power Amplifiers for Wireless and Radio Applications (PAWR), 2015,
[Reviewed] Performance Evaluation of Digital Colour Shift Keying for Visible Light CommunicationsNaoya Murata; Hiroki Shimamoto; Yusuke Kozawa; Yohtaro Umeda, In this paper, multilevel Digital Colour Shift Keying (DCSK) and DCSK using multi-colour LEDs are considered. Moreover, to increase the spectral efficiency of DCSK, Spatial Colour Shift Keying (SCSK) is proposed, in which DCSK is combined with Space Shift Keying. The symbol error rate of DCSK and SCSK performances are evaluated from theoretical analysis and simulation analysis, under consideration of the transmitter-receiver configuration within the room. Consequently, when the channel gain ratio is smaller than 1.7, the energy efficiency of DCSK is better than those of SCSK and Generalised Space Shift Keying (GSSK), on the other hand, SCSK is improved when the channel gain ratio becomes large. Moreover, when the number of transmitters is large, the spectral efficiency of SCSK can be improved compared with DCSK., IEEE
2015 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATION WORKSHOP (ICCW), 2015,
[Reviewed] Power-Amplifier Inserted Transversal Filter using High-Order Pass BandKouhei Nagasawa; Shota Fujioka; Kazuhiro Watanabe; Yohtaro Umeda; Yusuke Kozawa, Power amplifier inserted transversal filter amplifies in high efficiency and can adjust the center frequency and pass bandwidth. In addition, the filter suppresses the quantization noise that remains outside the desired signal band at the output of the filter. The reduction of the quantization noise is due to narrowing the pass bandwidth by increasing the number of paths. However, the circuit scale and the loss in power combining in the filter increase as the number of paths increases. To solve this problem, this paper proposes to use the higher-order passband of the transversal filter to narrowing the filter by increasing the delay difference between adjacent paths of the filter. This realizes passband characteristics almost equivalent to a large number of paths. In addition, this enables to suppress the increase in circuit scale and losses due the power combining. Computer simulation shows that a narrow-band filter can be realized with a small number of paths by using a higher-order passband. It also shows that the degradation in modulation accuracy is small due to the use of higher-order passband., IEEE
2015 IEEE INTERNATIONAL SYMPOSIUM ON RADIO-FREQUENCY INTEGRATION TECHNOLOGY (RFIT), 2015,
[Reviewed] Indoor Optical-Wireless Code-Shift-Keying with Two-Stages DemodulationShota Takayanagi; Hiromasa Habuchi; Yusuke Kozawa, In this paper, the code-shift-keying (CSK) system using the extended pseudo orthogonal M-sequence (EPOM) is considered in indoor optical-wireless channel. EPOM is one of optical pseudo-noise (PN) codes designed by the fusion of two PN codes. One is the modified pseudo orthogonal M-sequence sets (MPOMS), the other is the bi-orthogonal code. The CSK systems using the combined PN code demodulate with two stages. As the conventional optical PN code with two-stages demodulation, the pseudo-orthogonal extended prime code set (POEPC) has been proposed. This paper focuses on the comparison between the CSK system using EPOM and the CSK system using POEPC under the same information transmission efficiency. Consequently, the CSK system using EPOM is superior to the CSK system using POEPC., IEEE
2015 IEEE 4TH GLOBAL CONFERENCE ON CONSUMER ELECTRONICS (GCCE), 2015,
[Reviewed] Optical-Wireless Enhanced Code-Shift-Keying with IM/DDShota Takayanagi; Hiromasa Habuchi; Yusuke Kozawa, In this paper, the extended pseudo orthogonal Msequence is proposed for the optical-wireless code-shift-keying (CSK) system. The extended pseudo orthogonal M-sequence is a new optical pseudo-noise (PN) code which consists of the modified pseudo orthogonal M-sequence sets (MPOMS) and the bi-orthogonal code. The performance of the CSK systems is enhanced by increasing the number of the optical PN codes. As the conventional optical PN code, the bi-orthogonal code and the pseudo-orthogonal extended prime code set can generate the number of the optical PN codes same as the code length. The extended pseudo orthogonal M-sequence can achieve the performance enhancement of the CSK systems because of its generation of the large number of the codes per the code length. The CSK system using the extended pseudo orthogonal Msequence has better performance than the CSK systems using the conventional PN code., IEEE
2015 21ST ASIA-PACIFIC CONFERENCE ON COMMUNICATIONS (APCC), 2015,
[Reviewed] 照明可視光通信のための擬直交符号を用いた調光制御法尾崎 崇; 小澤 佑介; 楳田 洋太郎, Corresponding, 本稿では，照明可視光通信のために擬直交符号を用いた調光制御(明るさ調整)法が提案されている。さらに，本方式をマルチパルス-パルス位置変調方式に適用することで従来の調光制御法を用いた方式に比べ高い周波数利用効率を達成している。, The Institute of Image Information and Television Engineers
映像情報メディア学会誌, 25 Apr. 2014,
[Reviewed] Variable multi-pulse PPM using new dimming control method for visible light communicationsTakashi Ozaki; Yusuke Kozawa; Yohtaro Umeda, In this paper, we propose a variable multi-pulse pulse-position-modulation (VMPPM) system with a dimming control that combines the use of pseudo-orthogonal codes and MPPM. In VMPPM, r slots are selected from n MPPM slots and codes for data are generated in each selected r slot according to source data left perpendicular log(2) (nr) right perpendicular + r [bit/frame]. Therefore, VMPPM can achieve higher data-transmission rate than the conventional variable PPM (VPPM). Additionally, VMPPM can represent the dimming level of n - r + 1 stages by using the empty n - r slots. Moreover, the symbol error rate (SER) of VMPPM is evaluated through theoretical analysis. Also, we compare both the SER performance and the spectral efficiency of VMPPM with those of VPPM. Consequently, the data-transmission rate, the error rate performance and the spectral efficiency of VMPPM are better than those of VPPM., IEEE
2014 INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY AND ITS APPLICATIONS (ISITA), 2014,
[Reviewed] Improved Error Performance of Variable PPM for Visible Light CommunicationTakashi Ozaki; Yusuke Kozawa; Yohtaro Umeda, We propose a variable multi-pulse pulse-position-modulation (VMPPM) system with a dimming control that combines the use of pseudo-orthogonal codes and MPPM. In VMPPM, r slots are selected from n MPPM slots and codes for data are generated in each selected r slot according to source data [log(2) (n(r))] + r [bit/frame]. This enables VMPPM to achieve a higher data-transmission rate than the conventional variable PPM (VPPM). Additionally, VMPPM can represent the dimming level of n - r + 1 stages by using the empty n - r slots. In this paper, the symbol error rate (SER) of VPPM is investigated through theoretical analysis. In addition, the SER performance and spectral efficiency of VMPPM is compared with those of VPPM and variable rate MPPM (VR-MPPM). Specifically, the SER performance is evaluated by taking into account the human eye response. Consequently, VPPM can greatly decrease the maximum ratio of electrical signal power per bit to noise at SER = 10(-7) for conventional dimmable modulation schemes about 20 dB. Moreover, VMPPM is superior to VPPM in the spectral efficiency., IEEE
2014 INTERNATIONAL SYMPOSIUM ON WIRELESS PERSONAL MULTIMEDIA COMMUNICATIONS (WPMC), 2014,
[Reviewed] 光無線通信におけるPN符号を用いる階層化変調法羽渕 裕真; 小澤 佑介, これまでの光無線変調法は1種類の変調法を利用する場合が一般的であり,階層化変調法に関する検討もほとんど行われていない.本論文では,擬似雑音(PN)符号を用いることにより2種類の情報変調法を融合する光階層化変調方式が提案されている.特に,コードシフトキーイング(CSK)と振幅シフトキーイング(ASK)を融合したCSK-ASK方式,CSKとコード数キーイング(CNK)を融合したCSK-CNK方式,マルチパルス・パルス位置変調(MPPM)とCNKを融合したMPPM-CNK方式が提案されている.これらの方式は,信号パターンによって情報伝送する方式と信号電力によって情報伝送する方式を融合したものであり,各変調方式によって伝送距離や必要な同期精度が異なり,通信距離などに応じて受信情報量が異なる階層化が行える.本論文では,同期タイミングが完全である場合と同期誤差がある場合の誤り率特性が示され,各情報変調データを独立に復調できること,2種類の情報変調法の間で性能差があることが示されている., 一般社団法人電子情報通信学会
電子情報通信学会論文誌. B, 通信, 01 May 2013,
[Reviewed],
[Invited] Effectiveness of the network coding with frame slotted ALOHA on VANET
Hiroyuki Higano; Hiromasa Habuchi; Yusuke Kozawa
Proceeding of 2013 RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing(NCSP'13), Mar. 2013, [Reviewed]
Analysis of hierarchical multi-pulse PPM using modified pseudo orthogonal M-sequence setYusuke Kozawa; Hiromasa Habuchi, In this paper, to enhance the data transmission rate of the optical wireless hierarchical transmission system, the new hierarchical modulation scheme is proposed. The proposed system is designed based on multi-pulse pulse-position modulation (MPPM) using modified pseudo orthogonal M-sequence sets as a pseudo-noise code. The symbol error rate (SER) performance is derived taking into account the effect of the scintillation, background-noise, avalanche photo-diode (APD) noise, thermal noise, and signal dependence noise. Our results show that the data transmission rate performance improves significantly compared with the conventional MPPM system. Moreover, it is found that the proposed system can realize the hierarchical modulation scheme, and the SER performance of the proposed MPPM system can achieve that of the conventional MPPM system by increasing the number of slots for MPPM., IEEE
2012 INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY AND ITS APPLICATIONS (ISITA 2012), 2012,
[Reviewed] Performance analysis of multi-pulse PPM for optical wireless hierarchical transmission systemYusuke Kozawa; Hiromasa Habuchi, In this paper, the new optical wireless hierarchical modulation scheme is proposed. The proposed system is designed based on multi-pulse pulse-position modulation (MPPM) using modified pseudo orthogonal M-sequence sets as a pseudo-noise code. The symbol error rate (SER) performance is derived taking into account the effect of the scintillation, background-noise, avalanche photo-diode (APD) noise, thermal noise, and signal dependence noise. Data transmission rate is also obtained. Our results show that the data transmission rate performance improves significantly compared with the conventional MPPM system. Moreover, it is found that the proposed system can realize the hierarchical modulation scheme, and the SER performance of the proposed MPPM system can achieve that of the conventional MPPM system by increasing the number of selected slots for MPPM. © 2012 IEEE., IEEE
2012 IEEE Globecom Workshops, GC Wkshps 2012, 2012,
[Reviewed] Optical Wireless N-CSK with Modified Pseudo Orthogonal M-Sequence SetsYusuke Kozawa; Hiromasa Habuchi, In this paper, N-CSK (N parallel Codes Shift Keying) using modified pseudo orthogonal M-sequence sets (MPOMSs) to realize the parallel combinatory spread spectrum (PC/SS) communication system for the optical communications is proposed. Moreover, the upper bound of data transmission rate and the bit error rate (BER) performance of this N-CSK system using the chip-level detection are evaluated through theoretical analysis by taking into account the scintillation, background-noise, avalanche photo-diode (APD) noise, thermal noise, and signal dependence noise. It is shown that the upper bound of data transmission rate of the proposed system is better than those of OOK/CDM and SIK/CDM. Moreover, the upper bound of data transmission rate of the proposed system can achieve about 1.5 [bit/chip] when the code length of MPOMS is 64 [chip]., IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG
IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, Nov. 2011,
[Reviewed] Theoretical analysis of parallel combinatory spread-spectrum communication system for optical wireless communicationsYusuke Kozawa; Hiromasa Habuchi, In this paper, an N-CSK (N parallel Codes Shift Keying) using modified pseudo orthogonal M-sequence sets (MPOMS) for applying the parallel combinatory spread-spectrum (PC/SS) communication system to the optical communication is presented. Moreover, the bit error rate (BER) performance and the data transmission rate of the proposed system are evaluated through theoretical analysis by taking into account the scintillation, background-noise, avalanche photodiode (APD) noise, thermal noise, and signal dependence noise. Also, the performance comparison between the proposed system and the conventional systems (OOK/CDM, SIK/CDM, and N-CSK/CDM) are presented. Consequently, the proposed system can realize high data rate optical wireless communication because the data transmission rate of the proposed system is better than those of the conventional systems, and can achieve more than 1.0 [bit/chip]. © 2011 IEEE., IEEE
ICICS 2011 - 8th International Conference on Information, Communications and Signal Processing, 2011,
[Reviewed] A Comparison of Wireless Optical CDMA Systems Using Chip-Level DetectionYusuke Kozawa; Hiromasa Habuchi, In this paper the optimum combination of optical pseudo noise (PN) code and modulation scheme to achieve high total data transmission rate is presented Moreover the bit error rate (BER) performance of a wireless OCDMA system using chip level detection is evaluated through theoretical analysis in the multi user case It is shown that in a wireless OCDMA system with chip level detection the total data transmission rate of a multi pulse pulse position modulation (MPPM) systems with optical pseudo noise code generated by an M sequence is better than that of an MPPM system with optical orthogonal code and that of an MPPM system with an extended prime code sequence Moreover the total data trans mission rate of an MPPM/SIK system using modified pseudo orthogonal M sequence sets can achieve more than 10 [bit/chip], IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG
IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, Nov. 2010,
[Reviewed] Theoretical analysis of M-CSK/CDMA system in optical wireless channelYusuke Kozawa; Hiromasa Habuchi, In this paper, M-CSK with extended prime code sequence to enhance a data transmission rate of CSK is considered. Moreover, the bit error rate (BER) performance of M-CSK/CDMA is evaluated by taking into account scintillation, background-noise, avalanche photo-diode (APD) noise, thermal noise, and signal dependence noise through theoretical analysis. It is shown that the data transmission rate of the M-CSK system is better than that of the CSK system using extended prime code sequences. However, the BER performance of the M-CSK system is degraded by increasing the number of selected extended prime code sequences. © 2010 IEEE., IEEE
ISITA/ISSSTA 2010 - 2010 International Symposium on Information Theory and Its Applications, 2010,
[Reviewed] Analysis of Wireless Optical CDMA using Chip-Level DetectionYusuke Kozawa; Hiromasa Habuchi, In this paper, to achieve high maximum throughput performance, the optimum combination of the optical PN code and modulation scheme is presented. Moreover, bit error rate (BER) performances of the wireless OCDMA system using chip-level detection are evaluated from the theoretical analysis in the multi-user case. Consequently, in the wireless OCDMA system with the chip-level detection, the maximum throughput performance of the multi-pulse PPM (MPPM) systems with the optical pseudo noise code generated by M-sequence is better than that of the MPPM systems with optical orthogonal code and that of the MPPM system with extended prime code sequence., IEEE
IWSDA'09: PROCEEDINGS OF THE FOURTH INTERNATIONAL WORKSHOP ON SIGNAL DESIGN AND ITS APPLICATIONS IN COMMUNICATIONS, 2009,
[Reviewed] Theoretical Analysis of Optical Wireless CDMA with Modified Pseudo Orthogonal M-sequence SetsYusuke Kozawa; Hiromasa Habuchi, In this paper, to increase normalized throughput of the optical wireless code-division multiple-access (CDMA) system, modified pseudo orthogonal M-sequences (MPOMS) are considered as optical pseudo-noise (PN) code. Moreover, the bit error rate (BER) performance of the optical wireless CDMA system using multi-pulse pulse position modulation (MPPM) is also derived in the presence of the scintillation, background-noise, avalanche photo-diode (APD) noise, thermal noise and signal dependence noise. Consequently, the BER performance in consideration of normalized throughput of the MPPM system with MPOMS is superior to that of the MPPM system with conventional pseudo orthogonal M-sequences in the single-user case and multi-user case., IEEE
GLOBECOM 2009 - 2009 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1-8, 2009,
[Reviewed] Modified pseudo orthogonal M-sequence sets for synchronous optical-CDMA
Yusuke Kozawa; Hiromasa Habuchi
The 23rd International Technical Conference on Circuits/Systems, Computers and Communications (ITC-CSCC2008),, Jul. 2008, [Reviewed]
Increased Throughput Using Optical PPM-CDMAYusuke Kozawa; Hiromasa Habuchi, In this paper, to increase normalized throughput of pulse position modulation (PPM) in the optical CDMA system, the optical Multi-pulse PPM (MPPM) system with modified pseudo orthogonal M-sequence sets is proposed. Result from theoretical analysis of bit error rate (BER) performance of the proposed system is also presented. Consequently, the normalized throughput and BER of the proposed system axe better than those of the conventional MPPM system with the pseudo orthogonal M-sequences. Furthermore, BER of the proposed system is also superior to those of the conventional systems., IEEE
2008 INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY AND ITS APPLICATIONS, VOLS 1-3, 2008,
[Reviewed] Enhancement of Optical Wireless Multi-Pulse PPMYusuke Kozawa; Hiromasa Habuchi, In this paper, optical wireless multi-pulse pulse position modulation (MPPM) system with modified pseudo orthogonal M-sequence sets is proposed. Moreover, the symbol error rates of the proposed system are analyzed by taking into account the scintillation, background-noise, avalanche photo-diode (APD) noise, thermal noise, and signal dependence noise in the single-user case. Consequently, the normalized throughput in consideration of SER of the proposed system is superior to that of the conventional MPPM systems. Furthermore, the normalized throughput of the proposed system can achieve about 1.25 [bit/chip]., IEEE
GLOBECOM 2008 - 2008 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, 2008,
[Reviewed] Theoretical analysis of atmospheric optical PPM CDMA with pseudo-orthogonal M-sequencesYusuke Kozawa; Hiromasa Habuchi, in this paper, the atmospheric optical code-division multiple-access (CDMA) system with Pseudo-orthogonal M-sequences is proposed. The bit error rate (BER) of the proposed system using pulse position modulation (PPM) by taking into account the effects of the scintillation, avalanche photo-diode (APD) noise, thermal noise, and multiple access interference (MAI) are analyzed. By comparing with the optical orthogonal code (OOC) and the prime code, the proposed system with pseudo-orthogonal M-sequences is better than the systems with other PN codes. But, the scintillation has an enormous effect on the performance of the proposed system., IEEE
2007 IEEE 18TH INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS, VOLS 1-9, 2007,
[Reviewed] Theoretical analysis of atmospheric optical DS/SS with On-Off Orthogonal M-sequence PairsYusuke Kozawa; Hiromasa Habuchi, In this paper, atmospheric optical DS/SS systems with On-Off Orthogonal M-sequence Pairs are considered. The bit error rates of the On-Off Keying (OOK) DS/SS and the antipodal DS/SS are analyzed by taking into account the scintillation, background-noise, avalanche photo-diode (APD) noise, thermal noise, and multiple access interference (MAI). Moreover, the optical DS/SS systems using on-off orthogonal M-sequence pairs are compared with those using the extended prime code sequences. Consequently, the optical DS/SS using the on-off orthogonal M-sequence pairs is superior to the optical DS/SS using extended prime code sequences., IEEE
2007 6TH INTERNATIONAL CONFERENCE ON INFORMATION, COMMUNICATIONS & SIGNAL PROCESSING, VOLS 1-4, 2007,
[Reviewed]
