Electronics and Communications in Japan (Part I: Communications)最新文献_第6页

OVSF code allocation and two-stage combining method to reduce intercode interference in OFCDM system OFCDM系统中OVSF码分配和两段合并方法减少码间干扰

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-04-20 DOI: 10.1002/ecja.20381

Kazuhiko Hasegawa, Ryuichiro Shimura, Iwao Sasase

引用次数: 3

Rheometry experiment for a wire antenna aboard spacecraft at low frequencies 航天器上导线天线低频流变试验

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-04-20 DOI: 10.1002/ecja.20353

Tomohiko Imachi, Satoshi Yagitani, Ryoichi Higashi, Isamu Nagano

{"title":"Rheometry experiment for a wire antenna aboard spacecraft at low frequencies","authors":"Tomohiko Imachi, Satoshi Yagitani, Ryoichi Higashi, Isamu Nagano","doi":"10.1002/ecja.20353","DOIUrl":"10.1002/ecja.20353","url":null,"abstract":"For satellite observation of the electric fields of waves, a dipole antenna using a wire (wire antenna) is often used. An antenna with probes on both ends (probe antenna) is used for observation of the static electric field. For calibration of these antennas, the effective length of the antenna is a problem. In general, in AC wave observation, the effective length of the wire antenna is half the total length L and hence L/2. It has been verified that this is correct at frequencies of several hundred hertz or higher. However, in the GEOTAIL antenna, the same antenna is co-used for wave observation and the static field observation. Calibration is performed with an effective length of L/2 for wave observation with an effective length of L for static electric field measurement. Reliable data are obtained in both cases. This paper reports a rheometry experiment in which the output voltage of a small antenna is measured in water for the wire antenna, obtaining the frequency dependence of the effective length in the low-frequency region. It is found that the frequency dependence of the effective length depends on the antenna configuration. When a wire antenna with only its side surfaces insulation coated is placed in a conductive medium such as water or plasma, it is found that the effective length approaches L at low frequencies and L/2 at higher frequencies. This result is theoretically analyzed by means of an equivalent circuit and it is found that the phenomenon depends on the balance among surrounding medium, the insulation coating of the wire, and the input impedance of the receiver. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(9): 45–53, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20353","PeriodicalId":100405,"journal":{"name":"Electronics and Communications in Japan (Part I: Communications)","volume":"90 9","pages":"45-53"},"PeriodicalIF":0.0,"publicationDate":"2007-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/ecja.20353","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88896139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Content protection in adaptive content delivery 自适应内容交付中的内容保护

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-04-20 DOI: 10.1002/ecja.20341

Hiroshi Fujimoto, Takashi Suzuki, Takehiro Nakayama, Atushi Takeshita, Zulfikar Ramzan, Craig Gentry, Ravi Jain

{"title":"Content protection in adaptive content delivery","authors":"Hiroshi Fujimoto, Takashi Suzuki, Takehiro Nakayama, Atushi Takeshita, Zulfikar Ramzan, Craig Gentry, Ravi Jain","doi":"10.1002/ecja.20341","DOIUrl":"10.1002/ecja.20341","url":null,"abstract":"This paper considers environment-adaptive content delivery in which an intermediary modifies the content between the content provider and the content user, and proposes a system in which the provider can securely control content modification by the intermediary in accordance with usage rules defined in the content. In order to have the intermediary follow the usage rules strictly, it is indispensable to provide a content protection technique in which tampering with content or usage rules by a third party is prevented while permitting content modification by intermediaries approved by the provider within the scope of the usage rules. The authors consider the hash-tree signature method in which data deletion by the intermediary is permitted, and propose a signature system with a place holder extension permitting data addition. A highly efficient realization of the proposed signature system based on the hash-sign-switch (HSS) method is presented. The effectiveness of the approach is shown by a quantitative evaluation using the implemented system. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(9): 54–66, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20341","PeriodicalId":100405,"journal":{"name":"Electronics and Communications in Japan (Part I: Communications)","volume":"90 9","pages":"54-66"},"PeriodicalIF":0.0,"publicationDate":"2007-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/ecja.20341","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90179904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

MIMO-STBC scheme for intervehicle communications using decision feedback channel estimation method based on propagation feature at intersection 基于交叉口传播特征的决策反馈信道估计的MIMO-STBC方案

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-04-20 DOI: 10.1002/ecja.20400

Kenji Ito, Nobuo Itoh, Katsushi Sa()nda, Yoshio Karasawa

{"title":"MIMO-STBC scheme for intervehicle communications using decision feedback channel estimation method based on propagation feature at intersection","authors":"Kenji Ito, Nobuo Itoh, Katsushi Sa()nda, Yoshio Karasawa","doi":"10.1002/ecja.20400","DOIUrl":"10.1002/ecja.20400","url":null,"abstract":"This paper investigates an intervehicle communication method as a safe driving support system for intersection collision avoidance warnings. In this kind of system, realization of highly reliable communications in the physical layer is an absolute requirement. As a result, we propose a new MIMO-STBC (Space-Time Block Coding) method based on intersection propagation channel characteristics. MIMO transmission characteristics are determined by the propagation channel characteristics. First, we use a ray-tracing method simulation to clarify the propagation channel conditions, and then model the intersection propagation channel. We use the characteristics of this propagation channel to propose a MIMO-STBC method that utilizes decision feedback channel estimation, and verify the effectiveness of the proposed method in computer simulations. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(9): 1–15, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20400","PeriodicalId":100405,"journal":{"name":"Electronics and Communications in Japan (Part I: Communications)","volume":"90 9","pages":"1-15"},"PeriodicalIF":0.0,"publicationDate":"2007-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/ecja.20400","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75921048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Effective deflection control method in optical packet switching networks with shared buffers 共享缓冲区光分组交换网络中有效的偏转控制方法

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-04-20 DOI: 10.1002/ecja.20312

Kazuki Kawanabe, Tatsuro Takahashi

{"title":"Effective deflection control method in optical packet switching networks with shared buffers","authors":"Kazuki Kawanabe, Tatsuro Takahashi","doi":"10.1002/ecja.20312","DOIUrl":"10.1002/ecja.20312","url":null,"abstract":"Deflection routing is considered as a method to avoid packet collisions in an optical packet switching system. Deflection routing is a method of avoiding collision by link substitution, in which the colliding packet is sent to an idle link. Thus, the load on the congested part of the network is distributed and the bandwidth can be utilized effectively. When excessively frequent deflections are performed, however, the load on the whole network is increased, which produces an adverse effect. Another problem is that sequence errors can occur in the same flow due to differences of transmission delay, since packets are sent to different routes. From these points of view, this paper proposes a deflection control method which can remedy the above problems, and applies the proposed method to an optical packet switching system. In the proposed control method, class separation is performed with respect to sequence error, and deflection is permitted to packets of nonpriority class. This improves performance by large-scale grouping. In order to alleviate the increase in load on the whole network, a control algorithm which can deal with changes of the link utilization and the number of traversed hops is devised. The effectiveness of the approach is shown by computer simulation. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(9): 67– 77, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20312","PeriodicalId":100405,"journal":{"name":"Electronics and Communications in Japan (Part I: Communications)","volume":"90 9","pages":"67-77"},"PeriodicalIF":0.0,"publicationDate":"2007-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/ecja.20312","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81029541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Optical burst switched ring network with upstream prioritized switching and distributed fairness control 具有上行优先交换和分布式公平控制的光突发交换环网络

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-04-20 DOI: 10.1002/ecja.20338

Yutaka Arakawa, Naoaki Yamanaka, Iwao Sasase

{"title":"Optical burst switched ring network with upstream prioritized switching and distributed fairness control","authors":"Yutaka Arakawa, Naoaki Yamanaka, Iwao Sasase","doi":"10.1002/ecja.20338","DOIUrl":"10.1002/ecja.20338","url":null,"abstract":"With a view to constructing a metropolitan network that can flexibly handle highly bursty traffic, an optical burst switched ring network with upstream prioritized switching and distributed fairness control is proposed. In optical burst switching, high burst drop rates at intermediate nodes constitute a problem. In the proposed system, burst signal dropping at the relay nodes is eliminated by means of upstream prioritized switching. At the same time, by using distributed fairness control, the problem of upstream prioritized switching-related unfairness, in which positional priority provides higher priority to more distant transmission nodes, is resolved. Further, by modifying the reservation of downstream nodes by using the trailer packet after disconnection of the transmission, unnecessary bandwidth is eliminated and the throughput is improved. By computer simulation, the throughput and the fairness with regard to the throughput are evaluated. It is shown that the proposed architecture exhibits excellent characteristics even in cases of hot-spot traffic, in which concentrated traffic occurs at a particular destination. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(8): 30–39, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20338 Copyright © 2004 Wiley Periodicals, Inc.Copyright © 2007 Wiley Periodicals, Inc.","PeriodicalId":100405,"journal":{"name":"Electronics and Communications in Japan (Part I: Communications)","volume":"90 8","pages":"30-39"},"PeriodicalIF":0.0,"publicationDate":"2007-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/ecja.20338","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81155220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Experimental verification of measurement principle in standing wave radar capable of measuring distances down to zero meters 零米以下驻波雷达测量原理的实验验证

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-04-20 DOI: 10.1002/ecja.20375

Yoshihiro Okubo, Tetsuji Uebo

{"title":"Experimental verification of measurement principle in standing wave radar capable of measuring distances down to zero meters","authors":"Yoshihiro Okubo, Tetsuji Uebo","doi":"10.1002/ecja.20375","DOIUrl":"10.1002/ecja.20375","url":null,"abstract":"In general, it is difficult to measure short distances by radar, which has a minimum detection distance of several meters. The standing wave radar proposed by the present authors has a minimum detection distance of about 2 m when the frequency bandwidth is 76 MHz. A solution to reduce the minimum detection distance is to increase the frequency bandwidth. This is not realistic due to limits imposed by radio regulations. The authors have proposed a method with measurable distances down to 0 m without enlarging the bandwidth and have presented the configuration and the measurement principle. The measurement principle has been verified by numerical simulation. In the present paper, the measurement principle is experimentally verified by using an actual standing wave radar and the realizability of a standing wave radar with measurement capability down to 0 m is confirmed. It is shown that the distance to the target at locations closer than the minimum detection distance of 2 m (0.14, 0.3, 0.5, and 1 m) can be measured with an error of several centimeters for a frequency bandwidth of 76 MHz at 24 GHz. For distances less than 0.14 m, the target could not be placed closer than 0.14 m due to positional interference of the target and the antenna in the present experimental environment so that physical confirmation was not possible. However, at the confirmed distance, the range spectrum predicted from the theory is obtained. Hence, it is considered possible to make measurements without special restrictions. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(9): 25– 34, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20375","PeriodicalId":100405,"journal":{"name":"Electronics and Communications in Japan (Part I: Communications)","volume":"90 9","pages":"25-34"},"PeriodicalIF":0.0,"publicationDate":"2007-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/ecja.20375","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85101687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Investigation of radiated field analysis model for moment method from microstrip line on PCB PCB微带线矩法辐射场分析模型的研究

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-04-20 DOI: 10.1002/ecja.20354

Hiroaki Koyama, Masato Kawabata, Yasuhiro Ishida, Nobuo Kuwabara

{"title":"Investigation of radiated field analysis model for moment method from microstrip line on PCB","authors":"Hiroaki Koyama, Masato Kawabata, Yasuhiro Ishida, Nobuo Kuwabara","doi":"10.1002/ecja.20354","DOIUrl":"10.1002/ecja.20354","url":null,"abstract":"The method of moments and the FDTD method have been widely used for the analysis of radiated electromagnetic fields. In comparison with the FDTD method, the method of moments calculates the electromagnetic field by a light computational load and analyzes the far field accurately. A wire grid model of the printed circuit board placed on the upper plane of the imitated equipment has been reported and it can calculate the electromagnetic field below 1 GHz. However, the wire grid model using the calculation above 1 GHz has not been reported. This paper proposes the analytical model that can analyze the radiated electromagnetic fields with horizontal polarization at frequencies above 1 GHz. Since the contribution of the current on a microstrip line (MSL) is significant in the case of horizontal polarization, the proposed method attempts to simulate the current distribution by inserting impedances and admittances into the wire grid model of MSL. As a result of the studies, it is found that an analysis is possible with an accuracy within ±5 dB of the measured results in the frequency range of 1 to 3 GHz when the current distribution, calculated by the FDTD method, is simulated by inserting inductance and capacitance into the wire grid model. It is also found that the result of calculation by the model is similar to that by the FDTD method, which requires a computation time about 4 times longer. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(8): 20–29, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20354 Copyright © 2004 Wiley Periodicals, Inc.Copyright © 2007 Wiley Periodicals, Inc.","PeriodicalId":100405,"journal":{"name":"Electronics and Communications in Japan (Part I: Communications)","volume":"90 8","pages":"20-29"},"PeriodicalIF":0.0,"publicationDate":"2007-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/ecja.20354","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76472004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Packet forwarding along an explicit route using the unused address pool on a packet switching network 在包交换网络中，使用未使用的地址池沿显式路由转发报文

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-04-20 DOI: 10.1002/ecja.20308

Hideaki Imaizumi, Ken-Ichi Nagami, Osamu Nakamura, Jun Murai

{"title":"Packet forwarding along an explicit route using the unused address pool on a packet switching network","authors":"Hideaki Imaizumi, Ken-Ichi Nagami, Osamu Nakamura, Jun Murai","doi":"10.1002/ecja.20308","DOIUrl":"10.1002/ecja.20308","url":null,"abstract":"This paper considers a connectionless (CL) packet switching network, such as IP, and proposes a method in which unused addresses are used as labels for packet flows with various granularities, which are transferred along explicitly specified routes. Generally, in CL packet-switched networks, the next packet is selected and relayed to arrive at the destination host on the basis of the destination address attached to the packet. Consequently, it is impossible to transfer packets which have the same destination address but different requirements along separate routes. One technique for performing such a transfer is multi-protocol label switching (MPLS) and is based on a different transfer paradigm. The cost of this method is high because the transfer schemes of each participating router must be modified. To address this problem, this paper proposes a method for flow-based explicit route transfer. In the proposed method, a particular packet flow is allocated to an unused address so that an explicit route is composed from the unused address and the destination address of the packet is translated. In this method, the transfer scheme is kept essentially the same and explicit route transfer is realized only through a simple extension to the router. Depending on the mode of application, it is unnecessary to modify internal routers; the method can easily be applied to existing networks. In this paper, an application of the method to IP, as a typical CL packet switching network, is described, and the features of the proposed method are discussed. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(9): 78–89, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20308","PeriodicalId":100405,"journal":{"name":"Electronics and Communications in Japan (Part I: Communications)","volume":"90 9","pages":"78-89"},"PeriodicalIF":0.0,"publicationDate":"2007-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/ecja.20308","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85644617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Determination of satellite orbital elements by means of on-board GPS receiver and its verification 利用星载GPS接收机确定卫星轨道要素及其验证

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-04-20 DOI: 10.1002/ecja.20378

Yoshiwo Okamoto, Tomonao Hayashi, Koji Yokoyama, Shigeru Hosokawa, Yoshinari Masumoto

引用次数: 0