IEICE Transactions on Communications
Online ISSN : 1745-1345
Print ISSN : 0916-8516
Volume E97.B, Issue 5
Displaying 1-19 of 19 articles from this issue
Regular Section
  • Taek-Young YOUN, Dowon HONG
    Article type: PAPER
    Subject area: Fundamental Theories for Communications
    2014 Volume E97.B Issue 5 Pages 930-935
    Published: May 01, 2014
    Released on J-STAGE: May 01, 2014
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    Distance bounding protocols permit a verifier to compute the distance to a prover by measuring the execution time of n rounds of challenge-response authentication. Many protocols have been proposed to reduce the false acceptance rate of the challenge-response procedure. Until now, it has been widely believed that the lowest bound of the false acceptance rate is (1/2)n when n is the number of rounds and the prover can send only one response bit for each round. In this paper, we propose a new distance bounding protocol whose false acceptance rate is (1/3)n against the distance fraud attacks and the mafia fraud attacks. To reduce the false acceptance rate, we use two challenge bits for each iteration and introduce a way of expressing three cases with the use of only one response bit, the same bit length as existing protocols. Our protocol is the first distance bounding protocol whose false acceptance rate is lower than the currently believed minimal bound without increasing the number of response bits for each round.
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  • Tetsuya HAYASHI, Takashi SASAKI, Eisuke SASAOKA
    Article type: PAPER
    Subject area: Fiber-Optic Transmission for Communications
    2014 Volume E97.B Issue 5 Pages 936-944
    Published: May 01, 2014
    Released on J-STAGE: May 01, 2014
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    The stochastic behavior of inter-core crosstalk in multi-core fiber is discussed based on a theoretical model validated by measurements, and the effect of the crosstalk on the Q-factor in transmission systems, using multi-core fiber is investigated theoretically. The measurements show that the crosstalk rapidly changes with wavelength, and gradually changes with time, in obedience to the Gaussian distribution in I-Q planes. Therefore, the behavior of the crosstalk as a noise may depend on the bandwidth of the signal light. If the bandwidth is adequately broad, the crosstalk may behave as a virtual additive white Gaussian noise on I-Q planes, and the Q-penalty at the Q-factor of 9.8dB is less than 1dB when the statistical mean of the crosstalk from other cores is less than -16.7dB for PDM-QPSK, -23.7dB for PDM-16QAM, and -29.9dB for PDM-64QAM. If the bandwidth is adequately narrow, the crosstalk may behave as virtually static coupling that changes very gradually with time and heavily depends on the wavelength. To cope with a static crosstalk much higher than its statistical mean, a margin of several decibels from the mean crosstalk may be necessary for suppressing Q-penalty in the case of adequately narrow bandwidth.
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  • Kazuhiko KINOSHITA, Nariyoshi YAMAI, Koso MURAKAMI
    Article type: PAPER
    Subject area: Network System
    2014 Volume E97.B Issue 5 Pages 945-951
    Published: May 01, 2014
    Released on J-STAGE: May 01, 2014
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    The recent explosive growth in information networks has driven a huge increase in content. For efficient and flexible information retrieval over such large networks, agent technology has received much attention. We previously proposed an agent execution control method for time-constrained information retrieval that finds better results by terminating an agent that has already acquired results of high-enough quality or one that is unlikely to improve the quality of results with continued retrieval. However, this method assumed that all agents have identical time constraints. This leads to a disparity in the obtained score between users who give individual time constraints. In this paper, we propose a fair and efficient scheduling method based on the expected improvement of the highest score (EIS). The proposed method allocates all CPU resources to the agent that has the highest EIS to decrease the difference between users' scores and to increase the mean highest score of requested results.
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  • Yan-tao LIU, Ying TIAN, Jian-ping AN, Heng LIU
    Article type: PAPER
    Subject area: Network
    2014 Volume E97.B Issue 5 Pages 952-959
    Published: May 01, 2014
    Released on J-STAGE: May 01, 2014
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    We analyze the connectivity of simulation ad hoc networks, which use random mobility models. Based on the theorem of minimum degree, the study of connectivity probability is converted into an analysis of the probability of minimum node degree. Detailed numerical analyses are performed for three mobility models: random waypoint model, random direction model, and random walk model. For each model, the connectivity probability is calculated and its relations with the communication range r and the node number n are illustrated. Results of the analyses show that with the same network settings, the connectivity performance decreases in the following order: random walk model, random direction model, and random waypoint model. This is because of the non-uniform node distribution in the last two models. Our work can be used by researchers to choose, modify, or apply a reasonable mobility model for network simulations.
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  • Ajmal KHAN, Jae-Choong NAM, You-Ze CHO
    Article type: PAPER
    Subject area: Network
    2014 Volume E97.B Issue 5 Pages 960-966
    Published: May 01, 2014
    Released on J-STAGE: May 01, 2014
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    In vehicular ad hoc networks, the efficient and reliable dissemination of emergency messages in a highly mobile environment under dense or sparse network is a significant challenge. This paper proposes a new vehicular broadcast protocol, called ACK-CAST, that can operate effectively in both dense and sparse network scenarios. ACK-CAST relies on acknowledgment messages from one-hop neighbors to select the next rebroadcasting vehicle. Simulation results show that ACK-CAST outperforms the SERVUS protocol in terms of the end-to-end delay, message delivery ratio and network overhead.
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  • Oshani ERUNIKA, Kunitake KANEKO, Fumio TERAOKA
    Article type: PAPER
    Subject area: Network
    2014 Volume E97.B Issue 5 Pages 967-980
    Published: May 01, 2014
    Released on J-STAGE: May 01, 2014
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    Mobile IPv6 is an IETF (Internet Engineering Task Force) standard which permits node mobility in IPv6. To manage mobility, it establishes a centralized mediator, Home Agent (HA), which inevitably introduces several penalties like triangular routing, single point of failure and limited scalability. Some later extensions such as Global HAHA, which employed multiple HAs, made to alleviate above shortcomings by introducing Distributed Mobility Management (DMM) approach. However, Multiple HA model will not be beneficial, unless the HAs are located finely. But, no major research paper has focused on locating HAs. This paper examines impact of single and multiple HA placements in data plane, by using an Autonomous System (AS) level topology consisting of 30,000 nodes with several evaluation criteria. All possible placements of HA(s) are analysed on a fair, random set of 30,000 node pairs of Mobile Nodes (MN) and Correspondent Nodes (CN). Ultimate result provides a concise account of different HA placements: i.e. cost centrality interprets performance variation better than degree centrality or betweenness. 30,000 ASs are classified into three groups in terms of Freeman's closeness index and betweenness centrality: 1) high range group, 2) mid range group, and 3) low range group. Considering dual HA placement, if one HA is placed in an AS in the high range group, then any subsequent HA placement gives worse results, thus single HA placement is adequate. With the mid range group, similar results are demonstrated by the upper portion of the group, but the rest yields better results when combined with another HA. Finally, from the perspective of low range group, if the subsequent HA is placed in the high range group, it gives better result. On the other hand, betweenness based grouping yields varying results. Consequently, this study reveals that the Freeman's closeness index is most appropriate in determining impacts of HA placements among considered indices.
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  • Tien Hoang DINH, Go HASEGAWA, Masayuki MURATA
    Article type: PAPER
    Subject area: Network
    2014 Volume E97.B Issue 5 Pages 981-995
    Published: May 01, 2014
    Released on J-STAGE: May 01, 2014
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    Available bandwidth, along with latency and packet loss rate, is an essential metric for the efficient operation of overlay network applications. However, the measurement of available bandwidth creates a larger traffic overhead than other metrics. Measurement conflicts on route-overlapping paths can also seriously degrade measurement accuracy and cause a non-negligible increase in the network load. In this paper, we propose a distributed method for measuring the available bandwidth in overlay networks that can reduce measurement conflicts while maintaining high measurement accuracy at low cost. Our main idea is that neighboring overlay nodes exchange route information to detect overlapping paths and share the measurement results of overlapping paths to configure parameter settings for available bandwidth measurements. Our simulation results show that the relative errors in the measurement results of our method are approximately only 65% of those of the existing method. The measurement accuracy of our method remains better than that of the existing method when the total measurement traffic loads of both methods are equal.
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  • Qing LIU, Tomohiro ODAKA, Jousuke KUROIWA, Haruhiko SHIRAI, Hisakazu O ...
    Article type: PAPER
    Subject area: Network
    2014 Volume E97.B Issue 5 Pages 996-1011
    Published: May 01, 2014
    Released on J-STAGE: May 01, 2014
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    This paper presents an artificial fish swarm algorithm (AFSA) to solve the multicast routing problem, which is abstracted as a Steiner tree problem in graphs. AFSA adopts a 0-1 encoding scheme to represent the artificial fish (AF), which are then subgraphs in the original graph. For evaluating each AF individual, we decode the subgraph into a Steiner tree. Based on the adopted representation of the AF, we design three AF behaviors: randomly moving, preying, and following. These behaviors are organized by a strategy that guides AF individuals to perform certain behaviors according to certain conditions and circumstances. In order to investigate the performance of our algorithm, we implement exhaustive simulation experiments. The results from the experiments indicate that the proposed algorithm outperforms other intelligence algorithms and can obtain the least-cost multicast routing tree in most cases.
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  • Hung V. LE, Hasan Md. MOHIBUL, Takuichi HIRANO, Toru TANIGUCHI, Akira ...
    Article type: PAPER
    Subject area: Antennas and Propagation
    2014 Volume E97.B Issue 5 Pages 1012-1021
    Published: May 01, 2014
    Released on J-STAGE: May 01, 2014
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    The millimeter-wave band suffers strong attenuation due to rain. While calculating the link budget for a wireless system using this frequency band, the behavior of rain, attenuation due to rain, and the amount of degradation must be accurately understood. This paper presents an evaluation of the influence of rain and its attenuation on link performance in a Tokyo Institute of Technology (Tokyo Tech) millimeter-wave model mesh network. Conventional statistical analyses including cumulative rain rate distribution and specific rain attenuation constants are performed on data collected from 2009 onwards. The unique effects arising due to the highly localized behaviors of strong rainfalls have become clear and are characterized in terms of variograms rather than correlation coefficients. Spatial separation even in the small network here with links of less than 1 km provides effective diversity branches for better availability performance.
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  • Jaeyul CHOO, Chihyun CHO, Hosung CHOO
    Article type: PAPER
    Subject area: Antennas and Propagation
    2014 Volume E97.B Issue 5 Pages 1022-1029
    Published: May 01, 2014
    Released on J-STAGE: May 01, 2014
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    This paper designs tag antennas to satisfy three key goals: mounting on very small objects, extending the reading range with planar structures, and maintaining stable performance on various materials. First, the size of the tag is reduced up to 17% compared to the half-wavelength dipole without a large reduction in bandwidth and efficiency by introducing an inductively coupled feed structure. Second, the reading range is increased to 1.68 times that of the reference dipole tags while maintaining the planar structure using circular polarization characteristics. Finally, a stable reading range is achieved with a deviation in the reading range of only 30% of that of commercial tags on various objects by employing the capacitively-loaded and T-matching network.
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  • Masayuki MURAKAMI, Hiroyasu IKEDA
    Article type: PAPER
    Subject area: Electromagnetic Compatibility (EMC)
    2014 Volume E97.B Issue 5 Pages 1030-1043
    Published: May 01, 2014
    Released on J-STAGE: May 01, 2014
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    Although many companies have developed robots that assist humans in the activities of daily living, safety requirements and test methods for such robots have not been established. Given the risk associated with a robot malfunctioning in the human living space, from the viewpoints of safety and EMC, it is necessary that the robot does not create a hazardous situation even when exposed to possibly severe electromagnetic disturbances in the operating environment. Thus, in immunity tests for personal care robots, the safety functions should be more rigorously tested than the other functions, and be repeatedly activated in order to ascertain that the safety functions are not lost in the presence of electromagnetic disturbances. In this paper, immunity test procedures for personal care robots are proposed that take into account functional safety requirements. A variety of test apparatuses are presented, which were built for activating the safety functions of robots, and detecting whether they were in a safe state. The practicality of the developed immunity test system is demonstrated using actual robots.
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  • Yan CHENG, Seung-Hoon HWANG
    Article type: PAPER
    Subject area: Wireless Communication Technologies
    2014 Volume E97.B Issue 5 Pages 1044-1049
    Published: May 01, 2014
    Released on J-STAGE: May 01, 2014
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    In this paper, we investigate a combination scheme of subcarrier intensity-modulation (SIM) with spatial modulation (SM) for optical wireless communication. Using computer simulation, the performances of the proposed SIM/SM scheme are investigated and compared with those of the conventional SIM scheme in the additive white gaussian noise (AWGN) as well as in outdoor environment with turbulence induced fading characteristics. Numerical results show that the proposed SIM/SM scheme can outperform the conventional SIM in an environment with different spectral efficiencies. When the spectral efficiency is varied from 2bits/s/Hz to 4bits/s/Hz, an Eb/N0 gain of 2dB to 5dB is achieved, when the bit error rate of 10-5 is maintained. It shows that the employment of SM may further improve the power efficiency of SIM, when the number of subcarriers increases according to the spectral efficiency. When the spectral efficiency is 4bits/s/Hz, the SIM/SM scheme for 0.5 of log-irradiance variance in the log-normal turbulence channel shows the same performance as SIM with variance of 0.3. This means that the SIM/SM can be an alternative choice in even worse environments.
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  • Md Shohidul ISLAM, Jong-Myon KIM
    Article type: PAPER
    Subject area: Wireless Communication Technologies
    2014 Volume E97.B Issue 5 Pages 1050-1058
    Published: May 01, 2014
    Released on J-STAGE: May 01, 2014
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    Emerging networks characterized by growing speed and data insensitivity demand faster and scalable error handling. Prevalent decoders are based on dedicated hardware, offering considerable processing speed, but limited flexibility, programmability and scalability. This paper proposes an efficient approach to accelerate the extended-Hamming code decoder using a graphics processing unit (GPU), chosen for its low cost and extremely high-throughput parallel-computing capability. This paper compares the performance of the GPU-based approach with the equivalent sequential approaches that are performed on a central processing unit (CPU) and Texas Instruments TMS320C6742 digital signal processor (DSP) with varying packet sizes and error tolerances. Experimental results demonstrate that the proposed GPU-based approach outperforms the sequential approaches in terms of execution time and energy consumption.
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  • Tomoya TANDAI, Hiroshi SUZUKI, Kazuhiko FUKAWA, Satoshi SUYAMA
    Article type: PAPER
    Subject area: Wireless Communication Technologies
    2014 Volume E97.B Issue 5 Pages 1059-1071
    Published: May 01, 2014
    Released on J-STAGE: May 01, 2014
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    This paper proposes a multipacket-per-slot reservation-based random access protocol with multiuser detection (MD) and automatic repeat request (ARQ), called MPRMD, and analyzes its performance by computer simulations. In MPRMD, before data packet (DP) transmission, a user terminal (UT) transmits a small access request packet (AP) that is composed of an orthogonal preamble sequence and a UT identifier (UT-ID) in a randomly selected minislot during a short dedicated period. Even when several APs collide, a base station (BS) distinguishes them by matched filtering against the preamble part and then extracts the UT-IDs after separating each AP by MD. If the APs are not successfully detected, a small number of minislots are additionally arranged to retransmit them. Thus, by using MD under AP crowded conditions, BS can maximally detect the access requests in a short period, which results in reducing the overhead. Furthermore, in the assignment of a slot, BS intentionally assigns one slot to multiple UTs in order to enhance the efficiency and separates UT's DPs by MD. Since MPRMD can detect a multitude of access requests by utilizing MD in the short period and efficiently assign the slot to separable DPs by MD, it can enhance the system throughput. Computer simulations are conducted to demonstrate the effectiveness of MPRMD. It is shown that the maximum throughputs of MPRMD with the average SNR of 30dB reach 1.4 and 1.7 packets/slot when a data packet is 10 times and 50 times as long as a control packet, respectively.
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  • Wenquan FENG, Xiaodi XING, Qi ZHAO, ZuLin WANG
    Article type: PAPER
    Subject area: Wireless Communication Technologies
    2014 Volume E97.B Issue 5 Pages 1072-1079
    Published: May 01, 2014
    Released on J-STAGE: May 01, 2014
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    The large Doppler offset that exists in high dynamic environments poses a serious impediment to the acquisition of direct sequence spread spectrum (DSSS) signals. To ensure acceptable detection probabilities, the frequency space has to be finely divided, which leads to complicated acquisition structures and excessively long acquisition time at low SNR. A local frequency folding (LFF) method designed for combined application with established techniques dedicated to PN-code synchronization is proposed in this paper. Through modulating local PN-code block with a fixed waveform obtained by folding all frequency cells together, we eliminate the need for frequency search and ease the workload of acquisition. We also analyze the performance of LFF and find that the detection performance degradation from folding can be compensated by FFT-based coherent integration. The study is complemented with numerical simulations showing that the proposed method has advantages over unfolding methods with respect to detection probability and mean acquisition time, and the advantage becomes obvious but limited if the folded number gets larger.
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  • Nandita LAVANIS, Devendra JALIHAL
    Article type: PAPER
    Subject area: Wireless Communication Technologies
    2014 Volume E97.B Issue 5 Pages 1080-1086
    Published: May 01, 2014
    Released on J-STAGE: May 01, 2014
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    In this paper, the diversity multiplexing tradeoff (DMT) analysis of the non-coherent block-fading multiple antenna channel which uses a training-based channel estimation scheme at asymptotically high signal-to-noise ratios (SNRs) is extended to finite SNRs. This extension is performed for a single input multiple output (SIMO) maximal ratio combining (MRC) scheme. This analysis at finite SNRs is more useful because in practice, the training schemes operate at finite SNRs and their impact on DMT is more relevant at such SNRs. We show the non-applicability of the asymptotically high SNR relation, given by Zheng, to finite SNRs. We also show the equivalence of two existing training-based channel estimation schemes for any SIMO system, and using one of these, we compute the achievable finite-SNR DMT of the non-coherent SIMO-MRC scheme for two modes of the training scheme. We analyze the achievable finite-SNR DMT for different durations of training, modes of the training scheme, and SNRs. We show that the impact of the mode of the training scheme on finite-SNR DMT decreases as SNR increases. We also show that at asymptotically high SNRs, the achievable DMT in both modes of the SIMO-MRC scheme is equal to that of the non-coherent SIMO channel, as derived by Zheng.
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  • Zhonggui MA, Hongbo WANG
    Article type: PAPER
    Subject area: Terrestrial Wireless Communication/Broadcasting Technologies
    2014 Volume E97.B Issue 5 Pages 1087-1093
    Published: May 01, 2014
    Released on J-STAGE: May 01, 2014
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    Dynamic spectrum access is the key approach in cognitive wireless regional area networks, and it is adopted by secondary users to access the licensed radio spectrum opportunistically. In order to realize real-time secondary spectrum usage, a dynamic spectrum access model based on stochastic differential games is proposed to realize dynamic spectrum allocation; a Nash equilibrium solution to the model is given and analyzed in this paper. From an overall perspective, the relationships between available spectrum percentage and the spectrum access rate are studied. Changes in the available spectrum percentage of the cognitive wireless regional area networks involve a deterministic component and a stochastic component which depends upon an r-dimensional Wiener process. The Wiener process represents an accumulation of random influences over the interval, and it reflects stochastic and time-varying properties of the available spectrum percentage. Simulation results show that the dynamic spectrum access model is efficient, and it reflects the time-varying radio frequency environment. Differential games are useful tools for the spectrum access and management in the time-varying radio environment.
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  • Takeshi ONIZAWA, Hiroki SHIBAYAMA, Masashi IWABUCHI, Akira KISHIDA, Ma ...
    Article type: PAPER
    Subject area: Terrestrial Wireless Communication/Broadcasting Technologies
    2014 Volume E97.B Issue 5 Pages 1094-1102
    Published: May 01, 2014
    Released on J-STAGE: May 01, 2014
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    This paper describes a simple packet combining scheme with maximum likelihood detection (MLD) for multiple-input multiple-output with orthogonal frequency division multiplexing (MIMO-OFDM) in relay channels to construct reliable wireless links in wireless local area networks (LANs). Our MLD-based approach employs the multiplexed sub-stream signals in different transmit slots. The proposed scheme uses an additional combining process before MLD processing. Moreover, the proposed scheme sets the cyclic shift delay (CSD) operation in the relay terminal. We evaluate the performance of the proposed scheme by the packet error rate (PER) and throughput performance in the decode-and-forward (DF) strategy. First, we show that the proposed scheme offers approximately 4.5dB improvement over the conventional scheme in the received power ratio of the relay terminal to the destination terminal at PER =0.1. Second, the proposed scheme achieves about 1.6 times the throughput of the conventional scheme when the received power ratio of the relay terminal to the destination terminal is 3dB.
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  • Wei LIU, Yuan HU
    Article type: PAPER
    Subject area: Navigation, Guidance and Control Systems
    2014 Volume E97.B Issue 5 Pages 1103-1111
    Published: May 01, 2014
    Released on J-STAGE: May 01, 2014
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    With the development of global navigation satellite systems (GNSS), the interference among global navigation satellite systems, known as the radio frequency compatibility problem, has become a matter of great concern to system providers and user communities. The acceptable compatibility threshold should be determined in the radio frequency compatibility assessment process. However, there is no common standard for the acceptable threshold in the radio frequency compatibility assessment. This paper firstly introduces the comprehensive radio frequency compatibility methodology combining the spectral separation coefficient (SSC) and code tracking spectral sensitivity coefficient (CT_SSC). Then, a method for determination of the acceptable compatibility threshold is proposed. The proposed method considers the receiver processing phase including acquisition, code and carrier tracking and data demodulation. Simulations accounting for the interference effects are carried out at each time step and every place on earth. The simulations mainly consider the signals of GPS, Galileo and BeiDou Navigation Satellite System (BDS) in the L1 band. Results show that all of the sole systems are compatible with other GNSS systems with respect to a special receiver configuration used in the simulations.
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