IEICE Transactions on Communications
Online ISSN : 1745-1345
Print ISSN : 0916-8516
Volume E101.B, Issue 12
Displaying 1-12 of 12 articles from this issue
Regular Section
  • Chun-Lin LIN, Tzu-Hsiang LIN, Ruey-Yi WEI
    Article type: PAPER
    Subject area: Fundamental Theories for Communications
    2018 Volume E101.B Issue 12 Pages 2380-2387
    Published: December 01, 2018
    Released on J-STAGE: December 01, 2018
    Advance online publication: May 31, 2018
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    Bit-interleaved coded modulation with iterative decoding (BICM-ID) is suitable for correlated Rayleigh fading channels. Additionally, BICM-ID using differential encoding can avoid the pilot overhead. In this paper, we consider BICM-ID using 16-DAPSK (differential amplitude and phase-shift keying). We first derive the probability of receiving signals conditioned on the transmission of input bits for general differential encoding; then we propose two new 16-DAPSK bit labeling methods. In addition, convolutional codes for the new bit labeling are developed. Both the minimum distance and the simulation results show that the proposed labeling has better error performance than that of the original differential encoding, and the searched new codes can further improve the error performance.

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  • Yusaku HAYAMIZU, Miki YAMAMOTO, Elisha ROSENSWEIG, James F. KUROSE
    Article type: PAPER
    Subject area: Network
    2018 Volume E101.B Issue 12 Pages 2388-2396
    Published: December 01, 2018
    Released on J-STAGE: December 01, 2018
    Advance online publication: June 22, 2018
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    In-network guidance to off-path cache, Breadcrumbs, has been proposed for cache network. It guides content requests to off-path cached contents by using the latest content download direction pointer, breadcrumbs. In Breadcrumbs, breadcrumb pointer is overwritten when a new content download of the corresponding content passes through a router. There is a possibility that slightly old guidance information for popular contents might lead to better cached content than the latest one. In this paper, we propose a new in-network guidance, Multiple-Breadcrumbs, which holds old breadcrumbs even with the latest breadcrumb pointer generated with a new content download. We focus on its content search capability and propose Throughput Sensitive selection that selects the content source giving the best estimated throughput. Our performance evaluation gives interesting results that our proposed Multiple Breadcrumbs with Throughput Sensitive selection improves not only throughput for popular contents but also for unpopular contents.

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  • Jinfa WANG, Siyuan JIA, Hai ZHAO, Jiuqiang XU, Chuan LIN
    Article type: PAPER
    Subject area: Internet
    2018 Volume E101.B Issue 12 Pages 2397-2408
    Published: December 01, 2018
    Released on J-STAGE: December 01, 2018
    Advance online publication: June 22, 2018
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    Detecting anomalies, such as network failure or intentional attack in Internet, is a vital but challenging task. Although numerous techniques have been developed based on Internet traffic, detecting anomalies from the perspective of Internet topology structure is going to be possible because the anomaly detection of structured datasets based on complex network theory has become a focus of attention recently. In this paper, an anomaly detection method for the large-scale Internet topology is proposed to detect local structure crashes caused by the cascading failure. In order to quantify the dynamic changes of Internet topology, the network path changes coefficient (NPCC) is put forward which highlights the Internet abnormal state after it is attacked continuously. Furthermore, inspired by Fibonacci Sequence, we proposed the decision function that can determine whether the Internet is abnormal or not. That is the current Internet is abnormal if its NPCC is out of the normal domain calculated using the previous k NPCCs of Internet topology. Finally the new Internet anomaly detection method is tested against the topology data of three Internet anomaly events. The results show that the detection accuracy of all events are over 97%, the detection precision for three events are 90.24%, 83.33% and 66.67%, when k=36. According to the experimental values of index F1, larger values of k offer better detection performance. Meanwhile, our method has better performance for the anomaly behaviors caused by network failure than those caused by intentional attack. Compared with traditional anomaly detection methods, our work is more simple and powerful for the government or organization in items of detecting large-scale abnormal events.

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  • Keyu LU, Zhaoxin ZHANG
    Article type: PAPER
    Subject area: Internet
    2018 Volume E101.B Issue 12 Pages 2409-2424
    Published: December 01, 2018
    Released on J-STAGE: December 01, 2018
    Advance online publication: June 22, 2018
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    The Domain Name System (DNS) maps domain names to IP addresses. It is an important infrastructure in the Internet. Recently, DNS has experienced various security threats. DNS resolvers experience the security threats most frequently, since they interact with clients and they are the largest group of domain name servers. In order to eliminate security threats against DNS resolvers, it is essential to improve their “health status”. Since DNS resolvers' owners are not clear which DNS resolvers should be improved and how to improve “health status”, the evaluation of “health status” for DNS resolvers has become vital. In this paper, we emphasize five indicators describing “health status” for DNS resolvers, including security, integrity, availability, speed and stability. We also present nine metrics measuring the indicators. Based on the measurement of the metrics, we present a “health status” evaluation method with factor analysis. To validate our method, we measured and evaluated more than 30,000 DNS resolvers in China and Japan. The results showed that the proposed “health status” evaluation method could describe “health status” well. We also introduce instructions for evaluating a small number of DNS resolvers. And we discuss DNSSEC and its effects on resolution speed. At last, we make suggestions for inspecting and improving “health status” of DNS resolvers.

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  • Takashi MARUYAMA, Shigeo UDAGAWA
    Article type: PAPER
    Subject area: Antennas and Propagation
    2018 Volume E101.B Issue 12 Pages 2425-2434
    Published: December 01, 2018
    Released on J-STAGE: December 01, 2018
    Advance online publication: June 04, 2018
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    We propose waveguide to microstrip line transitions for automotive millimeter wave radar modules. The transitions perpendicularly connect one waveguide and one or two microstrip lines. The configuration is simple because it consists of a waveguide and a dielectric substrate with copper foils. Additionally the transitions do not need via holes on the substrate. It leads to lower costs and improved reliability. We have already proposed a via-less transition by using multi-stage impedance transformers. The impedance transformers are used for suppressing undesirable radiation from the transition as well as impedance matching. In this paper, we propose a new transition with the microstrip lines on the long axis of the waveguide while most transitions place the microstrip lines on the minor axis (electric field direction) of the waveguide. Though our transition uses bend structures of microstrip lines, which basically cause radiation, our optimized configuration can keep small radiation. We also design a transition with a single microstrip line. The proposed transition with 2 microstrip lines can be modified to the 1 microstrip line version with minimum radiation loss. Electromagnetic simulations confirm the small radiation levels expected. Additionally we fabricate the transitions with back to back structure and determine the transmission and radiation performance. We also fabricates the transition for a patch array antenna. We confirm that the undesirable radiation from the proposed transition is small and the radiation pattern of the array antenna is not worsen by the transition.

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  • Mengbo ZHANG, Lunwen WANG, Yanqing FENG, Haibo YIN
    Article type: PAPER
    Subject area: Wireless Communication Technologies
    2018 Volume E101.B Issue 12 Pages 2435-2444
    Published: December 01, 2018
    Released on J-STAGE: December 01, 2018
    Advance online publication: May 30, 2018
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    Spectrum sensing is the first task performed by cognitive radio (CR) networks. In this paper we propose a spectrum sensing algorithm for orthogonal frequency division multiplex (OFDM) signal based on deep learning and covariance matrix graph. The advantage of deep learning in image processing is applied to the spectrum sensing of OFDM signals. We start by building the spectrum sensing model of OFDM signal, and then analyze structural characteristics of covariance matrix (CM). Once CM has been normalized and transformed into a gray level representation, the gray scale map of covariance matrix (GSM-CM) is established. Then, the convolutional neural network (CNN) is designed based on the LeNet-5 network, which is used to learn the training data to obtain more abstract features hierarchically. Finally, the test data is input into the trained spectrum sensing network model, based on which spectrum sensing of OFDM signals is completed. Simulation results show that this method can complete the spectrum sensing task by taking advantage of the GSM-CM model, which has better spectrum sensing performance for OFDM signals under low SNR than existing methods.

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  • Jong-Kwang KIM, Seung-Jin CHOI, Young-Hwan YOU, Hyoung-Kyu SONG
    Article type: PAPER
    Subject area: Wireless Communication Technologies
    2018 Volume E101.B Issue 12 Pages 2445-2452
    Published: December 01, 2018
    Released on J-STAGE: December 01, 2018
    Advance online publication: June 22, 2018
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    Multiple input multiple output with orthogonal frequency division multiplexing (MIMO-OFDM) is used in various parts of wireless communication systems. Because the MIMO-OFDM system simultaneously transmits parallel data streams and each receive antenna receives all data streams at one time, the detection ability of the receiver is very important. Among the detection schemes suitable for OFDM, maximum likelihood (ML) detection has optimal performance, but its complexity is so high that it is infeasible. Linear detection schemes such as zero-forcing (ZF) and minimum mean square error (MMSE) have low complexity, but also low performance. Among non-linear detection schemes, the near-ML detection which is the sphere detection (SD) or the QR decomposition with M algorithm (QRD-M) also has optimal performance but the complexity of SD and QRD-M detection is also too high. Other non-linear detection schemes like successive interference cancellation (SIC) detection have low complexity. However, the performance of SIC detection is lower than other non-linear detection schemes. In this paper, selectively iterative detection is proposed for MIMO-OFDM system; it offers low complexity and good performance.

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  • Se-Jin KIM, Sang-Hyun BAE
    Article type: PAPER
    Subject area: Wireless Communication Technologies
    2018 Volume E101.B Issue 12 Pages 2453-2461
    Published: December 01, 2018
    Released on J-STAGE: December 01, 2018
    Advance online publication: June 04, 2018
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    This paper proposes a novel dynamic channel assignment scheme named interference-aware dynamic channel assignment (IA-DCA) for the downlink of enterprise small-cell networks (ESNs) that employ orthogonal frequency division multiple access (OFDMA) and frequency division duplexing (FDD). In ESNs, a lot of small-cell access points (SAPs) are densely deployed in a building and thus small-cell user equipments (SUEs) have more serious co-tier interference from neighbor SAPs than the conventional small-cell network. Therefore, in the proposed IA-DCA scheme, a local gateway (LGW) dynamically assigns different numbers of subchannel groups to SUEs through their serving SAPs according to the given traffic load and interference information. Through simulation results, we show that the proposed IA-DCA scheme outperforms other dynamic channel assignment schemes based on graph coloring algorithm in terms of the mean SUE capacity, fairness, and mean SAP channel utilization.

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  • Yanqing LIU, Liyun DAI
    Article type: PAPER
    Subject area: Wireless Communication Technologies
    2018 Volume E101.B Issue 12 Pages 2462-2470
    Published: December 01, 2018
    Released on J-STAGE: December 01, 2018
    Advance online publication: June 22, 2018
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    In this paper, we apply extended regularized channel inversion precoding to address the multiuser multiantenna downlink transmission problem. Different from conventional regularized channel inversion precoding, extended RCI precoding considers non-homogeneous channels, adjusts more regularization parameters, and exploits the information gained by inverting the covariance matrix of the channel. Two ways of determining the regularization parameters are investigated. First, the parameters can be determined by solving a max-min SINR problem. The constraints of the problem can be transformed to the second-order cone (SOC) constraints. The optimal solution of the problem can be obtained by iteratively solving a second-order cone programming (SOCP) problem. In order to reduce the computational complexity, a one-shot algorithm is proposed. Second, the sum-rate maximization problem is discussed. The simple gradient-based method is used to solve the problem and get the regularization parameters. The simulation results indicate that the proposed algorithms exhibit improved max-min SINR performance and sum-rate performance over RCI precoding.

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  • Hirokazu MIYAGI, Yukitoshi SANADA
    Article type: PAPER
    Subject area: Wireless Communication Technologies
    2018 Volume E101.B Issue 12 Pages 2471-2478
    Published: December 01, 2018
    Released on J-STAGE: December 01, 2018
    Advance online publication: June 04, 2018
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    This paper applies minimum mean square error (MMSE) interference rejection followed by joint maximum likelihood detection (MLD) to a receiver in a distributed antenna network (DAN). DAN receivers capture not only the desired signals, but also the interference signals from nearby uncoordinated antennas. For the overloaded signal situation, non-linear detection schemes such as joint MLD can be applied to the received signals. However, the amount of metric calculations in joint MLD increases exponentially with the number of signal streams. Therefore, MMSE interference rejection followed by MLD detection is proposed. The proposed scheme reduces the complexity by a factor of 1/2M(NT-1) where NT is the number of interference signals with 2MQAM modulation. The effect of residual interference after the MMSE interference rejection is evaluated. Numerical results obtained through computer simulation and experiment show that the performance of the proposed scheme is about 4.0dB worse at a bit error rate (BER) of 10-3 than that of the joint MLD while its complexity is four times lower for QPSK signal streams. The BER performance degradation can be suppressed to about 2.5dB by adjusting the value of the coefficient in the MMSE matrix.

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  • Weibo WANG, Jinghuan SUN, Ruiying DONG, Yongkang ZHENG, Qing HUA
    Article type: PAPER
    Subject area: Wireless Communication Technologies
    2018 Volume E101.B Issue 12 Pages 2479-2486
    Published: December 01, 2018
    Released on J-STAGE: December 01, 2018
    Advance online publication: June 13, 2018
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    Indoor fingerprint location based on WiFi in large-scale indoor parking lots is more and more widely employed for vehicle lookup. However, the challenge is to ensure the location functionality because of the particularity and complexities of the indoor parking lot environment. To reduce the need to deploy of reference points (RPs) and the offline sampling workload, a partition-fitting fingerprint algorithm (P-FP) is proposed. To improve the location accuracy of the target, the PS-FP algorithm, a sampling importance resampling (SIR) particle filter with threshold based on P-FP, is further proposed. Firstly, the entire indoor parking lot is partitioned and the environmental coefficients of each partitioned section are gained by using the polynomial fitting model. To improve the quality of the offline fingerprint database, an error characteristic matrix is established using the difference between the fitting values and the actual measured values. Thus, the virtual RPs are deployed and C-means clustering is utilized to reduce the amount of online computation. To decrease the fluctuation of location coordinates, the SIR particle filter with a threshold setting is adopted to optimize the location coordinates. Finally, the optimal threshold value is obtained by comparing the mean location error. Test results demonstrated that PS-FP could achieve high location accuracy with few RPs and the mean location error is only about 0.7m. The cumulative distribution function (CDF) show that, using PS-FP, 98% of location errors are within 2m. Compared with the weighted K-nearest neighbors (WKNN) algorithm, the location accuracy by PS-FP exhibit an 84% improvement.

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  • Ryota OKUMURA, Jun FUJIWARA, Keiichi MIZUTANI, Hiroshi HARADA
    Article type: PAPER
    Subject area: Terrestrial Wireless Communication/Broadcasting Technologies
    2018 Volume E101.B Issue 12 Pages 2487-2497
    Published: December 01, 2018
    Released on J-STAGE: December 01, 2018
    Advance online publication: May 30, 2018
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    In this paper, an enhanced feathery receiver initiated transmission (eF-RIT) protocol is proposed for wireless smart utility network (Wi-SUN) systems with high traffic bi-directional communications such as emergency gas automatic meter infrastructure (AMI) cases. Firstly, we evaluate the conventional F-RIT protocol by simulation and experiment. The measurement results show that the IEEE 802.15.4e compliant conventional F-RIT protocol can achieve over 90% transmission success rates under the practical AMI specified conditions. However, the transmission success rates decline in high traffic environments. Detailed analyses indicate the degradation of the performance is caused by the timeout problem which occurs when the destination terminal is in the wait duration of the data transmission, and so does not transmit an RIT data request frame. To overcome this problem, we propose the eF-RIT protocol that suppresses the frequency of timeout occurrence. The proposed eF-RIT protocol is also evaluated by simulation and experiment. The evaluation results indicate that the proposed eF-RIT protocol reduces the incident of timeout by up to 31%, and achieves transmission success rates as high as 90% when the data generation rate is 1.0×10-2s-1.

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