IEICE Transactions on Communications
Online ISSN : 1745-1345
Print ISSN : 0916-8516
Volume E93.B, Issue 4
Displaying 1-44 of 44 articles from this issue
Special Section on Information and Communication Technology for Wellness and Medical Applications
  • Ryuji KOHNO
    2010 Volume E93.B Issue 4 Pages 795
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    Download PDF (69K)
  • Masaru SUGIMACHI, Toru KAWADA, Kazunori UEMURA
    Article type: INVITED PAPER
    2010 Volume E93.B Issue 4 Pages 796-801
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL FREE ACCESS
    Effective countermeasures against explosive increase in healthcare expenditures are urgently needed. A paradigm shift in healthcare is called for, and academics and governments worldwide are working hard on the application of information and communication technologies (ICT) as a feasible and effective measure for reducing medical cost. The more prevalent the disease and the easier disease outcome can be improved, the more efficient is medical ICT in reducing healthcare cost. Hypertension and diabetes mellitus are such examples. Chronic heart failure is another disease in which patients may benefit from ICT-based medical practice. It is conceivable that daily monitoring of hemodynamics together with appropriate treatments may obviate the expensive hospitalization. ICT potentially permit continuous monitoring with wearable or implantable medical devices. ICT may also help accelerate the development of new therapeutic devices. Traditionally effectiveness of treatments is sequentially examined by sacrificing a number of animals at a given time point. These inefficient and inaccurate methods can be replaced by applying ICT to the devices used in chronic animal experiments. These devices allow researchers to obtain biosignals and images from live animals without killing them. They include implantable telemetric devices, implantable telestimulation devices, and imaging devices. Implanted rather than wired monitoring and stimulation devices permit experiments to be conducted under even more physiological conditions, i.e., untethered, free-moving states. Wireless communication and ICT are indispensible technologies for the development of such telemetric and telestimulation devices.
    Download PDF (1040K)
  • John R. FARSEROTU, John F.M. GERRITS, Jérôme ROUSSELOT
    Article type: INVITED PAPER
    2010 Volume E93.B Issue 4 Pages 802-810
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL FREE ACCESS
    This paper provides an overview of CSEMs FM-UWB PHY-MAC proposal to IEEE802.15.6, Task Group 6, Body Area Networks. The proposed solution provides for an ultra low power, yet robust and reliable solution for low data rate medical BAN. The paper examines the key features and performance aspects of the proposal.
    Download PDF (1487K)
  • Keiki TAKADAMA, Kazuyuki HIROSE, Hiroyasu MATSUSHIMA, Kiyohiko HATTORI ...
    Article type: PAPER
    2010 Volume E93.B Issue 4 Pages 811-818
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    This paper proposes the sleep stage estimation method that can provide an accurate estimation for each person without connecting any devices to human's body. In particular, our method learns the appropriate multiple band-pass filters to extract the specific wave pattern of heartbeat, which is required to estimate the sleep stage. For an accurate estimation, this paper employs Learning Classifier System (LCS) as the data-mining techniques and extends it to estimate the sleep stage. Extensive experiments on five subjects in mixed health confirm the following implications: (1) the proposed method can provide more accurate sleep stage estimation than the conventional method, and (2) the sleep stage estimation calculated by the proposed method is robust regardless of the physical condition of the subject.
    Download PDF (933K)
  • Katsuhiro WATANABE, Kenichi TAKIZAWA, Tetsushi IKEGAMI
    Article type: PAPER
    2010 Volume E93.B Issue 4 Pages 819-825
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    This paper proposes a joint source-channel coding technology to transmit periodic vital information such as an electrocardiogram. There is an urgent need for a ubiquitous medical treatment space in which personalized medical treatment is automatically provided based on measured vital information. To realize such treatment and reduce the constraints on the patient, wireless transmission of vital information from a sensor device to a data aggregator is essential. However, the vital information has to be correctly conveyed through wireless channels. In addition, sensor devices are constrained by their battery power. Thus, a coding technique that provides robustness to noise, channel efficiency and low power consumption at encoding is essential. This paper presents a coding method that uses correlation of periodic vital information in the time domain, and provides a decoding scheme that uses the correlation as side information in a maximum a posteriori probability algorithm. Our results show that the proposed method provides better performance in terms of mean squared error after decoding in comparison to differential pulse-code modulation, and the uncoded case.
    Download PDF (1789K)
  • Haruka SUZUKI, Marco HERNANDEZ, Ryuji KOHNO
    Article type: PAPER
    2010 Volume E93.B Issue 4 Pages 826-832
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    This paper presents hybrid type-II automatic repeat request (H-ARQ) for wireless wearable body area networks (BANs) based on ultra wideband (UWB) technology. The proposed model is based on three schemes, namely, high rate optimized rate compatible punctured convolutional codes (HRO-RCPC), Reed Solomon (RS) invertible codes and their concatenation. Forward error correction (FEC) coding is combined with simple cyclic redundancy check (CRC) error detection. The performance is investigated for two channels: CM3 (on-body to on-body) and CM4 (on-body to a gateway) scenarios of the IEEE802.15.6 BAN channel models for BANs. It is shown that the improvement in performance in terms of throughput and error protection robustness is very significant. Thus, the proposed H-ARQ schemes can be employed and optimized to suit medical and non-medical applications. In particular we propose the use of FEC coding for non-medical applications as those require less stringent quality of service (QoS), while the incremental redundancy and ARQ configuration is utilized only for medical applications. Thus, higher QoS is guaranteed for medical application of BANs while allowing coexistence with non-medical applications.
    Download PDF (1067K)
  • Qiong WANG, Jianqing WANG
    Article type: PAPER
    2010 Volume E93.B Issue 4 Pages 833-841
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    Ultra wideband (UWB) on-body communication is attracting much attention in biomedical applications. In this paper, the performance of UWB on-body communication is investigated based on a statistically extracted on-body channel model, which provides detailed characteristics of the multi-path-affected channel with an emphasis on various body postures or body movement. The possible data rate, the possible communication distance, as well as the bit error rate (BER) performance are clarified via computer simulation. It is found that the conventional correlation receiver is incompetent in the multi-path-affected on-body channel, while the RAKE receiver outperforms the conventional correlation receiver at a cost of structure complexity. Different RAKE receiver structures are compared to show the improvement of the BER performance.
    Download PDF (589K)
  • Songjun LEE, Doosu NA, Bonmin KOO
    Article type: LETTER
    2010 Volume E93.B Issue 4 Pages 842-845
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    Wireless sensor networks with a star network topology are commonly applied for health monitoring systems. To determine the condition of a patient, sensor nodes are attached to the body to transmit the data to a coordinator. However, this process is inefficient because the coordinator is always communicating with each sensor node resulting in a data processing workload for the coordinator that becomes much greater than that of the sensor nodes. In this paper, a method is proposed to reduce the number of data transmissions from the sensor nodes to the coordinator by establishing a threshold for data from the biological signals to ensure that only relevant information is transmitted. This results in a dramatic reduction in power consumption throughout the entire network.
    Download PDF (180K)
  • Takahiro AOYAGI, Kenichi TAKIZAWA, Takehiko KOBAYASHI, Jun-ichi TAKADA ...
    Article type: LETTER
    2010 Volume E93.B Issue 4 Pages 846-849
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    An implantable WBAN path-loss model for a capsule endoscopy which is used for examining digestive organs, is developed by conducting simulations and experiments. First, we performed FDTD simulations on implant WBAN propagation by using a numerical human model. Second, we performed FDTD simulations on a vessel that represents the human body. Third, we performed experiments using a vessel of the same dimensions as that used in the simulations. On the basis of the results of these simulations and experiments, we proposed the gradient and intercept parameters of the simple path-loss in-body propagation model.
    Download PDF (221K)
  • Young-Sun SEO, Dae-Young KIM, Jinsung CHO
    Article type: LETTER
    2010 Volume E93.B Issue 4 Pages 850-853
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    WBANs provide communication services in the vicinity of the human body. Since WBANs utilize both MICS frequency band for implant medical applications and ISM frequency band for medical and consumer electronics (CE) applications, MAC protocols in WBAN should be designed considering flexibility between medical and CE applications. In this letter, we identify the requirements of WBAN MAC protocols and propose a WBAN MAC protocol which satisfies the requirements. In order to provide transmission flexibility for various applications, we present the dynamic CFP allocation and opportunity period. Extensive simulation results show that the proposed protocol achieves improved throughput and latency in WBAN environment compared with IEEE 802.15.4.
    Download PDF (196K)
  • Jing-Wei LIU, Moshaddique Al AMEEN, Kyung-Sup KWAK
    Article type: LETTER
    2010 Volume E93.B Issue 4 Pages 854-857
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    Network life time and hence device life time is one of the fundamental metrics in wireless body area networks (WBAN). To prolong it, especially those of implanted sensors, each node must conserve its energy as much as possible. While a variety of wake-up/sleep mechanisms have been proposed, the wake-up radio potentially serves as a vehicle to introduce vulnerabilities and attacks to WBAN, eventually resulting in its malfunctions. In this paper, we propose a novel secure wake-up scheme, in which a wake-up authentication code (WAC) is employed to ensure that a BAN Node (BN) is woken up by the correct BAN Network Controller (BNC) rather than unintended users or malicious attackers. The scheme is thus particularly implemented by a two-radio architecture. We show that our scheme provides higher security while consuming less energy than the existing schemes.
    Download PDF (420K)
  • Shyr-Kuen CHEN, Pi-Chung WANG
    Article type: LETTER
    2010 Volume E93.B Issue 4 Pages 858-861
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    In this letter, we develop an anycast-based emergency service for healthcare wireless sensor networks. The new service could operate with sensors to detect and activate an alarm system based on predefined conditions that are specific to the patient and the disease. The new service is implemented on 802.15.4 ZigBee which usually has large control overhead and long transmission times. To improve the service performance, our service identifies the closest emergency service provider to alleviate the control overhead and achieve immediate assistance when a patient requests for an emergency service. We also increase the reliability of packet transmission by using a Recovery Point scheme. Our simulations and experiment demonstrate that our scheme is efficient and feasible for healthcare wireless sensor networks.
    Download PDF (309K)
Regular Section
  • Jihyun PARK, Jeongsu LEE, Jeonghyun KIM, Jaecheol RYOU
    Article type: PAPER
    Subject area: Fundamental Theories for Communications
    2010 Volume E93.B Issue 4 Pages 862-870
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    A multicast content service, including numerous devices, requires an efficient group key management scheme as one of its core components. The purpose of group key management is to provide a secure key-sharing scheme among the members of a group so that messages transmitted via broadcasting or multicasting are not exposed to non-members. The Chinese Remaindering Group Key (CRGK) is an efficient group key management scheme based on the Chinese Remainder Theorem (CRT). It optimizes the number of re-key messages, the user-side key computation cost, and the number of stored keys. However, CRGK is not fit for a group with a large number of members because of the high computation complexity of the CRT. In this paper, we propose a Hierarchical CRGK (HCRGK) scheme that supports a group with a large number of members. We improved CRGK by adopting it to include an n-ary tree structure. The tree approach simplifies the group key management by distributing the group key computation to subgroups. Our scheme requires at most (logmN + 1) re-key messages for a group with N members and a short computation time even when the group is very large.
    Download PDF (414K)
  • Miroslav SAMARDZIJA, Jiro HIROKAWA, Makoto ANDO
    Article type: PAPER
    Subject area: Devices/Circuits for Communications
    2010 Volume E93.B Issue 4 Pages 871-878
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    A series of windows in the narrow wall of a fully-dielectric-filled rectangular waveguide to feed partially-dielectric-filled oversized-rectangular waveguide is presented. The overall structure is single-layer and 3-dimensional however; the waveguide which is uniform along the height is analyzed by the 2-dimensional method of moments and the oversized waveguide which is uniform in the longitudinal direction of the waveguide is analyzed by the 2-dimensional mode matching. It is found that utilizing simple mode conversions between the two orthogonally uniform structures is sufficient for obtaining the results similar to those of a 3-dimensional solver HFSS. The parameters for the windows designed for a uniform input division are presented. A simulation shows that a 12 window array provides a 3.5% bandwidth in terms of reflection below −20dB. The uniform excitation of the quasi-TEM wave is confirmed in the 60GHz band by measuring a uniform aperture field in amplitude and phase over the slotted oversized-waveguide.
    Download PDF (322K)
  • Ho Jong KANG, Hyung Rai OH, Hwangjun SONG
    Article type: PAPER
    Subject area: Network
    2010 Volume E93.B Issue 4 Pages 879-888
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    In this paper, we present an effective overlay real-time video multicast system over the Internet. The proposed system effectively integrates overlay multicast technology and video compression technology. Overlay multicast tree and target bit rate are determined to satisfy the given average delay constraint, and H.263+ rate control is implemented to enhance the human visual perceptual quality over the multicast tree. Finally, experimental results are provided to show the performance of the proposed overlay video multicast system over the Internet.
    Download PDF (1058K)
  • Antonio ALMEIDA
    Article type: PAPER
    Subject area: Network
    2010 Volume E93.B Issue 4 Pages 889-906
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    We present a congestion control algorithm for the Internet and assess its stability. The algorithm has low operation complexity and exercises control over sources without keeping per-flow information. Given the lack of support for explicit-rate feedback in the Internet, we discuss an implementation where feedback is based on explicit binary indications. We assess the stability through a discrete-time model and present simulation results showing the efficacy of the algorithm. The obtained results indicate that when the algorithm is used to control sources that support explicit binary feedback, its stability is not affected and its performance is close to that obtained with sources that support explicit-rate feedback.
    Download PDF (2041K)
  • Nagao OGINO, Hajime NAKAMURA
    Article type: PAPER
    Subject area: Network
    2010 Volume E93.B Issue 4 Pages 907-915
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    The establishment of inter-domain traffic engineered paths is a requisite to accomplishing an end-to-end bandwidth guarantee and end-to-end resource optimization. Though the inter-domain paths must be reliable, it is difficult to compute suitable backup inter-domain paths in advance when the traffic engineering information is not disclosed outside of each domain. This means that the inter-domain path computation must satisfy the severe requirement of path establishment delay, since all inter-domain paths traversing the links in failure need to be computed after the failure occurs. Though several inter-domain path computation schemes have been proposed, their relative characteristics remain unknown. First, this paper classifies the conventional inter-domain path computation schemes into two types, i.e. end-to-end and per-domain schemes, and compares their performances under various traffic loads. Based on results of the comparisons, this paper proposes an adaptive inter-domain path computation scheme that can satisfy the severe requirement of the path establishment delay. In this scheme, the domain sequence from the source node to the destination node is divided into multiple sub-domain sequences according to the traffic load in each domain. The end-to-end path computation scheme is applied to the sub-domain sequences under heavy traffic loads, while the per-domain path computation scheme is applied to those under normal traffic loads. The simulation results show that the proposed scheme can adaptively satisfy the requirement for the path establishment delay while it maintains the optimality of path computation, even if the traffic load applied to each domain changes.
    Download PDF (814K)
  • Ting-Chao HOU, Chih-Wei HSU
    Article type: PAPER
    Subject area: Network
    2010 Volume E93.B Issue 4 Pages 916-927
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    Previous research shows that the IEEE 802.11 DCF channel contention mechanism is not capable of providing throughput fairness among nodes in different locations of the wireless mesh network. The node nearest the gateway will always strive for the chance to transmit data, causing fewer transmission opportunities for the nodes farther from the gateway, resulting in starvation. Prior studies modify the DCF mechanism to address the fairness problem. This paper focuses on the fairness study when TCP flows are carried over wireless mesh networks. By not modifying lower layer protocols, the current work identifies TCP parameters that impact throughput fairness and proposes adjusting those parameters to reduce frame collisions and improve throughput fairness. With the aid of mathematical formulation and ns2 simulations, this study finds that frame transmission from each node can be effectively controlled by properly controlling the delayed ACK timer and using a suitable advertised window. The proposed method reduces frame collisions and greatly improves TCP throughput fairness.
    Download PDF (1355K)
  • Atsuo TACHIBANA, Yuichiro HEI, Tomohiko OGISHI, Shigehiro ANO
    Article type: PAPER
    Subject area: Network Management/Operation
    2010 Volume E93.B Issue 4 Pages 928-937
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    This paper presents an IP performance management system having the triple frameworks of performance measurement, topology monitoring and data analysis. The system infers the causal location of the performance degradation with a network tomographic approach. Since the Internet is still highly prone to performance deterioration due to congestion, router failure, and so forth, not only detecting performance deterioration, but also monitoring topology and locating the performance-degraded segments in real-time is vital to ensure that Internet Service Providers can mitigate or prevent such performance deterioration. The system is implemented and evaluated through a real-world experiment and its considerable potential for practical network operations is demonstrated.
    Download PDF (876K)
  • Yoshitaka HARA, Hiroshi KUBO
    Article type: PAPER
    Subject area: Wireless Communication Technologies
    2010 Volume E93.B Issue 4 Pages 938-947
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    This paper proposes an efficient multiuser relay scheme in OFDMA systems. In the proposed scheme, multiple terminals transmit their data packets simultaneously in the same subband and multiple relay stations retransmit their received signals in different subbands after subband conversion. A base station (BS) extracts individual packets from received signals in the different subbands. In advance of data transmission, the BS selects appropriate terminals so that the BS can extract individual data packets successfully. Numerical results show that the proposed relay scheme achieves higher system throughput than the conventional relay scheme when scheduling is applied to a larger number of terminals than the number of relay stations.
    Download PDF (705K)
  • Min Li HUANG, Jin LEE, Hendra SETIAWAN, Hiroshi OCHI, Sin-Chong PARK
    Article type: PAPER
    Subject area: Terrestrial Radio Communications
    2010 Volume E93.B Issue 4 Pages 948-960
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    With the growing demand for high-performance multimedia applications over wireless channels, we need to develop a Medium Access Control (MAC) system that supports high throughput and quality of service enhancements. This paper presents the standard analysis, design architecture and design issues leading to the implementation of an IEEE 802.11e based MAC system that supports MAC throughput of over 100Mbps. In order to meet the MAC layer timing constraints, a hardware/software co-design approach is adopted. The proposed MAC architecture is implemented on the Xilinx Virtex-II Pro Field-Programmable Gate Array (FPGA) (XC2VP70-5FF1704C) prototype, and connected to a host computer through an external Universal Serial Bus (USB) interface. The total FPGA resource utilization is 11, 508 out of 33, 088 (34%) available slices. The measured MAC throughput is 100.7Mbps and 109.2Mbps for voice and video access categories, transmitted at a data rate of 260Mbps based on IEEE 802.11n Physical Layer (PHY), using the contention-based hybrid coordination function channel access mechanism.
    Download PDF (1881K)
  • Sheng ZHOU, Zhisheng NIU
    Article type: PAPER
    Subject area: Terrestrial Radio Communications
    2010 Volume E93.B Issue 4 Pages 961-970
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    With simultaneous multi-user transmissions, spatial division multiple access (SDMA) provides substantial throughput gain over the single user transmission. However, its implementation in WLANs with contention-based IEEE 802.11 MAC remains challenging. Problems such as coordinating and synchronizing the multiple users need to be solved in a distributed way. In this paper, we propose a distributed MAC protocol for WLANs with SDMA support. A dual-mode CTS responding mechanism is designed to accomplish the channel estimation and user synchronization required for SDMA. We analytically study the throughput performance of the proposed MAC, and dynamic parameter adjustment is designed to enhance the protocol efficiency. In addition, the proposed MAC protocol does not rely on specific physical layer realizations, and can work on legacy IEEE 802.11 equipment with slight software updates. Simulation results show that the proposed MAC outperforms IEEE 802.11 significantly, and that the dynamic parameter adjustment can effectively track the load variation in the network.
    Download PDF (381K)
  • Kaikai CHI, Xiaohong JIANG, Baoliu YE, Susumu HORIGUCHI
    Article type: PAPER
    Subject area: Terrestrial Radio Communications
    2010 Volume E93.B Issue 4 Pages 971-981
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    Recently, network coding has been applied to the loss recovery of reliable multicast in wireless networks [19], where multiple lost packets are XOR-ed together as one packet and forwarded via single retransmission, resulting in a significant reduction of bandwidth consumption. In this paper, we first prove that maximizing the number of lost packets for XOR-ing, which is the key part of the available network coding-based reliable multicast schemes, is actually a complex NP-complete problem. To address this limitation, we then propose an efficient heuristic algorithm for finding an approximately optimal solution of this optimization problem. Furthermore, we show that the packet coding principle of maximizing the number of lost packets for XOR-ing sometimes cannot fully exploit the potential coding opportunities, and we then further propose new heuristic-based schemes with a new coding principle. Simulation results demonstrate that the heuristic-based schemes have very low computational complexity and can achieve almost the same transmission efficiency as the current coding-based high-complexity schemes. Furthermore, the heuristic-based schemes with the new coding principle not only have very low complexity, but also slightly outperform the current high-complexity ones.
    Download PDF (1208K)
  • Hiroshi SAITO
    Article type: PAPER
    Subject area: Integrated Systems for Communications
    2010 Volume E93.B Issue 4 Pages 982-992
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    A fuel-supply system using movable fuel-supply vehicles (FSVs) is proposed and its performance is evaluated. Both FSVs and vehicles requesting fuel are equipped with networked sensors. The sensors in FSVs are location sensors, and those in vehicles requesting fuel are for determining the remaining amount of fuel and the location of the vehicle. The time from when a fuel request is generated until the request is satisfied is the most basic performance metric for this system. Explicit formulas for the probabilistic distribution of this request time are also derived. Numerical examples show that the number of movable FSVs can be smaller than that of fixed fuel stations by about 80% or more than two orders of magnitude. This result suggests that movable FSVs may reduce the cost of the fuel supply infrastructure for alternative-fuel vehicles such as fuel-cell vehicles.
    Download PDF (1278K)
  • Sangjoon PARK, Sooyong CHOI, Seung-Hoon HWANG
    Article type: LETTER
    Subject area: Fundamental Theories for Communications
    2010 Volume E93.B Issue 4 Pages 993-996
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    A continuous belief propagation (BP) decoding algorithm for a hybrid automatic repeat request (ARQ) system is proposed in this paper. The proposed continuous BP decoding algorithm utilizes the extrinsic information generated in the last iteration of the previous transmission for a continuous progression of the decoding through retransmissions. This allows the continuous BP decoding algorithm to accelerate the decoding convergence for codeword determination, especially when the number of retransmissions is large or a currently combined packet has punctured nodes. Simulation results verify the effectiveness of the proposed continuous BP decoding algorithm.
    Download PDF (210K)
  • Xueqin JIANG, Moon Ho LEE, Tae Chol SHIN
    Article type: LETTER
    Subject area: Fundamental Theories for Communications
    2010 Volume E93.B Issue 4 Pages 997-1000
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    This letter presents an approach to the construction of multiple-rate quasi-cyclic (QC) low-density parity-check (LDPC) codes based on hyperplanes (μ-flats) of two different dimensions in Euclidean geometries. The codes constructed with this method have the same code length, multiple-rate and large stopping sets while maintaining the same basic hardware architecture. The code performance is investigated in terms of the bit error rate (BER) and compared with those of the LDPC codes which are proposed in IEEE 802.16e standard. Simulation results show that our codes perform very well and have low error floors over the AWGN channel.
    Download PDF (114K)
  • Yier YAN, Moon Ho LEE
    Article type: LETTER
    Subject area: Transmission Systems and Transmission Equipment for Communications
    2010 Volume E93.B Issue 4 Pages 1001-1004
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    Interleave-division multiple access (IDMA) inherits the peak-to-average power ratio (PAPR) problem especially with large number of multiple layers. Clipping transmission is a really simple and efficient method, but clipping noise is a tradeoff [1], [2] to its performance. Due to different weighting factors [2], an ordering technique is considered in this letter to recursively cancel the partial clipping noise at each detection. Simulation results show that the performance is close to that of unclipped IDMA chip in the high SNR region (8-9dB).
    Download PDF (141K)
  • Ryou SOUGEN, Keisuke IKUSHIMA, Osanori KOYAMA, Makoto YAMADA, Yutaka K ...
    Article type: LETTER
    Subject area: Optical Fiber for Communications
    2010 Volume E93.B Issue 4 Pages 1005-1008
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    Optimum conditions of the laser power P and the scan speed V were investigated experimentally so as to burn and remove the jacket of a 4-fiber ribbon completely by a system with a CO2 laser. It has been clarified that the optimum region can be given by 3 lines, which represent 2 lower limits of the laser power, depending on the scan speed, and an upper limit of the laser power to avoid soot from remaining on the fibers at high laser power region. The optimum conditions enable us to remove the jacket effectively by the system to provide excess-fiber-free compact packaging of optical components.
    Download PDF (613K)
  • Hyuntae PARK, Hyunjin KIM, Hong-Sik KIM, Sungho KANG
    Article type: LETTER
    Subject area: Switching for Communications
    2010 Volume E93.B Issue 4 Pages 1009-1012
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    This letter proposes a fast IP address lookup algorithm based on search space reduction. Prefixes are classified into three types according to the nesting relationship and a large forwarding table is partitioned into multiple small trees. As a result, the search space is reduced. The results of analyses and experiments show that the proposed method offers higher lookup and updating speeds along with reduced memory requirements.
    Download PDF (231K)
  • Haeryong PARK
    Article type: LETTER
    Subject area: Network
    2010 Volume E93.B Issue 4 Pages 1013-1015
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    Lee-Lee-Kim-Jeong proposed a hybrid authentication scheme [1] to alleviate the latent security problems of mobile multi-hop networks. In this letter, we show that the Lee-Lee-Kim-Jeong scheme is insecure against the intercept attack.
    Download PDF (178K)
  • Taeshik SHON, Eui-jik KIM, Jeongsik IN, Yongsuk PARK
    Article type: LETTER
    Subject area: Network
    2010 Volume E93.B Issue 4 Pages 1016-1019
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    In this letter, we propose an energy efficient hybrid architecture, the Hybrid MAC-based Robust Architecture (HMR), for wireless sensor networks focusing on MAC layer's scheduling and adaptive security suite as a security sub layer. A hybrid MAC layer with TDMA and CSMA scheduling is designed to prolong network life time, and the multi-channel TDMA based active/sleep scheduling is presented. We also present the security related functionalities needed to employ a flexible security suite to packets dynamically. Implementation and testbed of the proposed framework based on IEEE 802.15.4 are shown as well.
    Download PDF (616K)
  • Byung-Bog LEE, Se-Jin KIM, Seung-Yeon KIM, Hyong-Woo LEE, Seung-Wan RY ...
    Article type: LETTER
    Subject area: Network
    2010 Volume E93.B Issue 4 Pages 1020-1023
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    This letter proposes a wakeup-on-demand scheme based on the idea that a device should be awakened just when it has to receive a packet from a neighboring device. To prove this scheme, this letter proposes a mathematical model based on the busy cycle of M/G/1 queuing systems to obtain a battery lifetime of one-hop cluster-topology shaped W-WSN.
    Download PDF (378K)
  • Junseok KIM, Younggoo KWON
    Article type: LETTER
    Subject area: Network
    2010 Volume E93.B Issue 4 Pages 1024-1028
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    The IEEE 802.15.4a standard enables geographical routing in ZigBee networks but previous geographical routing algorithms can suffer high packet loss due to the interference effects. This letter proposes an interference-aware energy-efficient geographical routing algorithm for the IEEE 802.15.4a networks. The proposed algorithm estimates the energy cost by considering the interference effects and forwards a packet to the neighbor with the lowest energy cost to advance. Experimental results show that the proposed algorithm outperforms the previous algorithms in terms of the delivery ratio and the energy consumption.
    Download PDF (313K)
  • Jieun YU, Heejun ROH, Jun CAO, Sangheon PACK, Wonjun LEE, Ding-Zhu DU, ...
    Article type: LETTER
    Subject area: Network
    2010 Volume E93.B Issue 4 Pages 1029-1032
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    We propose a novel topology control scheme that reduces the transmission power of nodes and increases the network connectivity, based on the fact that Cooperative Communication (CC) technology can bridge disconnected networks. Simulation results demonstrate that our scheme greatly increases the connectivity for a given transmission power, compared to other topology control schemes.
    Download PDF (323K)
  • Yao YU, Yu ZHOU, Kanglian ZHAO, Sidan DU
    Article type: LETTER
    Subject area: Network
    2010 Volume E93.B Issue 4 Pages 1033-1036
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    A novel routing protocol, named candidate-based routing, for mobile ad hoc networks is presented. Instead of flooding over the whole network, it improves and rebuilds routing paths among a limited number of candidate nodes, which are dynamically elected without incurring or exchanging any additional information. Experimental results show that the proposed protocol performs well in terms of overhead and improvement in route efficiency, especially in the high mobility speed environments.
    Download PDF (277K)
  • Sungyeon KIM, Jang-Won LEE
    Article type: LETTER
    Subject area: Wireless Communication Technologies
    2010 Volume E93.B Issue 4 Pages 1037-1040
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    In most cases in wireless networks, a user has a two-way communication that consists of two sessions: uplink and downlink sessions, and its overall satisfaction to the communication depends on the quality of service of both sessions. However, in most previous approaches in wireless resource allocation, the satisfactions of a user for its uplink and downlink sessions are modeled separately and treated independently, which fails to accurately model user's overall satisfaction to its communication. Hence, in this paper we model user's overall satisfaction to its communication considering both its uplink and downlink sessions. To this end, we propose a novel concept for a utility function to model user's overall satisfaction to its communication, which is called a user-level utility function, considering user's satisfaction to uplink and downlink sessions jointly. To show the appropriateness of our approach, we apply our user-level utility functions to scheduling problems in TDMA wireless networks and show the performance improvement of our approach over the traditional approach that does not treat uplink and downlink sessions of a user jointly.
    Download PDF (192K)
  • Zhenyu XIAO, Li SU, Depeng JIN, Lieguang ZENG
    Article type: LETTER
    Subject area: Wireless Communication Technologies
    2010 Volume E93.B Issue 4 Pages 1041-1044
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    RAKE receivers are generally employed to collect multipath energy in single-carrier ultra-wideband (SC-UWB) systems and direct-sequence ultra-wideband (DS-UWB) systems. Performance of RAKE receivers in these two kinds of systems is studied and compared with each other in this letter. Both theoretical analysis and simulation results over IEEE 802.15.3a UWB channels are presented. Our results show that, with the same signal to noise ratio (SNR) per bit, the same occupied bandwidth and the same number of RAKE fingers, RAKE receivers with maximum ratio combination (MRC) in SC-UWB systems can achieve exactly the same performance as that in DS-UWB systems.
    Download PDF (219K)
  • Seungwoo JEON, Hanjin LEE, Jihoon LEE
    Article type: LETTER
    Subject area: Wireless Communication Technologies
    2010 Volume E93.B Issue 4 Pages 1045-1048
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    This letter suggests an opportunistic resource scheduling scheme for supporting users with variety of services in wireless network. This scheme is designed to increase resource utilization while meeting diverse quality of service (QoS) requirements. It can be achieved by considering the channel status and the urgency for QoS support synthetically.
    Download PDF (119K)
  • ASADUZZAMAN, Hyung-Yun KONG
    Article type: LETTER
    Subject area: Wireless Communication Technologies
    2010 Volume E93.B Issue 4 Pages 1049-1052
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    Motivated by the recent research in crosslayer design of cooperative wireless network, we propose a distributed cooperative routing algorithm for a multihop multi-relay wireless network to achieve selection diversity. We propose two algorithms, rate optimal path selection and outage optimal path selection, to satisfy the different requirements of the systems. Both algorithms work on distributed processing without requiring any centralized controller. Simulations are conducted to evaluate the performance of the proposal. The results of the simulations show that the proposed routing algorithms significantly improve the end-to-end data rate and outage performance compared with noncooperative routing protocols.
    Download PDF (111K)
  • Tsui-Tsai LIN
    Article type: LETTER
    Subject area: Wireless Communication Technologies
    2010 Volume E93.B Issue 4 Pages 1053-1056
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    In this letter, DFT-based channel estimation (CE) with a strong interference detector is proposed for OFDM systems. Computer simulations demonstrate that the proposed scheme achieves similar performance to an interference-free system and is a significant enhancement over conventional methods.
    Download PDF (289K)
  • Jae Ho HWANG, Jae Moung KIM
    Article type: LETTER
    Subject area: Terrestrial Radio Communications
    2010 Volume E93.B Issue 4 Pages 1057-1060
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    This paper introduces a coordinate calculation method for a real-time locating system. A ToA algorithm is used to obtain the target node coordinates, but a conventional DC method, which incurs heavy calculation time, is not suitable for embedded systems. This paper proposes the use of a P-control in the PID control algorithm to resolve real-time locating system issues. Performance measures of the accumulated operator number and position error are evaluated. It is shown that the PID method has less calculation and more robust performance than the DC method.
    Download PDF (423K)
  • Hyunduk JUNG, Jechan HAN, Jaiyong LEE
    Article type: LETTER
    Subject area: Terrestrial Radio Communications
    2010 Volume E93.B Issue 4 Pages 1061-1064
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    OFDMA femtocells in the macrocellular network of which frequency reuse factor is 1 cause serious interference to macrocell users, while the femtocells improve the performance of indoor users. In this letter, a novel downlink resource allocation algorithm for OFDMA femtocell networks is proposed to reduce interference between the macrocells and the femtocells. This algorithm allocates femtocell subchannels to avoid interference to macrocell users in the femtocell coverage, and minimizes the total transmission power of the femtocell to reduce the negative effect on the performance of the macrocell. Simulation results are provided to present the performance of the proposed algorithm.
    Download PDF (166K)
  • Yoshihisa TAKAYAMA, Morio TOYOSHIMA, Hiroo KUNIMORI
    Article type: LETTER
    Subject area: Optical Wireless Communications
    2010 Volume E93.B Issue 4 Pages 1065-1068
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    The effect of wavefront compensation in beam transmission is estimated for ground to satellite laser communications. A numerical analysis is performed using the combination of the isoplanatic angle, the atmospheric coherence length and the point-ahead angle to find the aperture size of the beam transmission with which the wavefront compensation effect appears most strongly.
    Download PDF (288K)
  • Fan ZHU, Yiqun WU, Zhisheng NIU
    Article type: LETTER
    Subject area: Energy in Electronics Communications
    2010 Volume E93.B Issue 4 Pages 1069-1072
    Published: April 01, 2010
    Released on J-STAGE: April 01, 2010
    JOURNAL RESTRICTED ACCESS
    In wireless networks, sleep mode based power saving mechanisms can reduce the energy consumption at the expense of additional packet delay. This letter analyzes its packet queueing delay and wireless terminals' energy efficiency. Based on the analysis, optimal sleep window size can be derived to optimize terminal energy efficiency with delay constraint.
    Download PDF (323K)
feedback
Top