Electronics and Communications in Japan (Part I: Communications)最新文献_第4页

A proposal of multipath reliable communication technique considering unstable links 一种考虑不稳定链路的多径可靠通信技术

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-05-25 DOI: 10.1002/ecja.20405

Tomohiko Yagyu, Masahiro Jibiki

{"title":"A proposal of multipath reliable communication technique considering unstable links","authors":"Tomohiko Yagyu, Masahiro Jibiki","doi":"10.1002/ecja.20405","DOIUrl":"10.1002/ecja.20405","url":null,"abstract":"Recently, with advances in cellular phones and wireless LAN technologies, mixed environments consisting of a fixed network and a wireless network have become commonplace. Also, information networks represented by the Internet are now indispensable for daily life. Hence, demands for highly reliable communications in a mixed environment of fixed and wireless networks have increased. However, wireless networks have the problem of easily generated packet loss due to various factors such as obstacles and interference. In a network consisting of a link with a high packet loss rate and high instability, the end-to-end packet arrival rate is significantly degraded. In addition, the entire network may become unstable due to frequency updating of the paths as a result of losses in routing control packets. To enhance the packet arrival rate, it is effective to use a multipath communications system in which several copies of the packets are sent by different paths. In this paper, based on path design considering the introduction of the intermittent state as a link condition, and introduction of the concepts of interruption-tolerant path and route calculation considering interference, a multipath communication system is proposed that enhances the end-to-end packet arrival rate while the control load is reduced in a network consisting of unstable links. By means of simulation it is shown that the control load can be kept small during communications while the packet arrival rate is improved over that in the conventional system. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(11): 1–11, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20405","PeriodicalId":100405,"journal":{"name":"Electronics and Communications in Japan (Part I: Communications)","volume":"90 11","pages":"1-11"},"PeriodicalIF":0.0,"publicationDate":"2007-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/ecja.20405","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74181447","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

Dynamic load balancing for the reduction of network traffic using network transferable computers 使用网络可转移计算机减少网络流量的动态负载平衡

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-05-25 DOI: 10.1002/ecja.20345

Megumi Hiyasuki, Shinji Inoue, Yoshiaki Kakuda, Kenji Toda, Kuniyasu Suzaki

{"title":"Dynamic load balancing for the reduction of network traffic using network transferable computers","authors":"Megumi Hiyasuki, Shinji Inoue, Yoshiaki Kakuda, Kenji Toda, Kuniyasu Suzaki","doi":"10.1002/ecja.20345","DOIUrl":"10.1002/ecja.20345","url":null,"abstract":"Dynamic load balancing (DLB) making use of network transferable computers (NTC) and Mobile IP is a new approach to performing load balancing for network traffic. In client– server systems when access requests to a specific server become particularly high from time to time, excessive amounts of network traffic will be generated on the route connecting to the server. With a server that is receiving a high concentration of requests, the provision of a mirror server can help provide load balancing to deal with issues of host performance, but it is not necessarily the best approach when the objective is principally to balance the load of the traffic on the network. In the DLB approach, the server is given the capability to migrate across the network; the server can therefore be moved to a location from which the route over which request and response packets to the server are causing congestion can be avoided. Since this results in the corresponding traffic being eliminated from the given network route, it allows the load balancing of network traffic. The proposed method is constructed via the use of an NTC system, Mobile IP, and a server migration manager. The server migration manager system can provide the following functionality. First, it is able to analyze information obtained from the network in which the server is located and provide predictions necessary for determining migration decisions. Next it can determine whether or not the server should actually migrate and in the case that it does can determine the location to migrate to. We have conducted evaluations of this method in simulation experiments and confirmed that traffic was reduced on the targeted network route. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(11): 48– 60, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20345","PeriodicalId":100405,"journal":{"name":"Electronics and Communications in Japan (Part I: Communications)","volume":"90 11","pages":"48-60"},"PeriodicalIF":0.0,"publicationDate":"2007-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/ecja.20345","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90296235","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

DOA estimation of desired signals by cyclic ESPRIT based on noise subspace and its performance improvement 基于噪声子空间的循环ESPRIT信号DOA估计及其性能改进

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-05-25 DOI: 10.1002/ecja.20304

Yoshiyuki Inagaki, Nobuyoshi Kikuma, Hiroshi Hirayama, Kunio Sakakibara

{"title":"DOA estimation of desired signals by cyclic ESPRIT based on noise subspace and its performance improvement","authors":"Yoshiyuki Inagaki, Nobuyoshi Kikuma, Hiroshi Hirayama, Kunio Sakakibara","doi":"10.1002/ecja.20304","DOIUrl":"10.1002/ecja.20304","url":null,"abstract":"Because of the rapid development of mobile communications and ITS (intelligent transport systems), the electromagnetic wave propagation environment is becoming complex, and there is an increasing demand for techniques to estimate the direction of arrival with high resolution and to reduce the effect of interference waves. Among these, Cyclic MUSIC and Cyclic ESPRIT, in which the direction of the arriving wave can be estimated selectively by utilizing the periodic stationary property of the arriving wave, are attracting attention. The authors are proposing Cyclic ESPRIT based on the noise subspace (NS Cyclic ESPRIT) in order to remedy the performance degradation produced by the fact that the correlation matrix of the array input used in Cyclic ESPRIT is not a Hermitian matrix. However, when the number of snapshots is finite in the estimation of arrival direction by Cyclic MUSIC or Cyclic ESPRIT, the interference wave component remaining in the correlation matrix has an adverse effect on the accuracy of direction-of-arrival estimation. Consequently, adaptive spatial smoothing processing and generalized eigenvalue decomposition are introduced into NS Cyclic ESPRIT in this study, aiming at reduction of the remaining interference component and at performance improvement in direction-of-arrival estimation. A computer simulation verifies that the performance in direction-of-arrival estimation in NS Cyclic ESPRIT is improved. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(11): 95–104, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20304","PeriodicalId":100405,"journal":{"name":"Electronics and Communications in Japan (Part I: Communications)","volume":"90 11","pages":"95-104"},"PeriodicalIF":0.0,"publicationDate":"2007-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/ecja.20304","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84257711","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

Route diversity effect on multipoint-to-multipoint (MP-MP) fixed wireless systems with mesh network topologies recommended in ITU-R F.1704 采用ITU-R F.1704推荐的网状网络拓扑结构的多点对多点(MP-MP)固定无线系统的路由分集效应

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-05-25 DOI: 10.1002/ecja.20334

Shinobu Nanba, Satoshi Konishi, Yoji Kishi, Shinichi Nomoto

{"title":"Route diversity effect on multipoint-to-multipoint (MP-MP) fixed wireless systems with mesh network topologies recommended in ITU-R F.1704","authors":"Shinobu Nanba, Satoshi Konishi, Yoji Kishi, Shinichi Nomoto","doi":"10.1002/ecja.20334","DOIUrl":"10.1002/ecja.20334","url":null,"abstract":"Broadband fixed wireless access (FWA) systems using submillimeter and millimeter bands are expected to function as large-capacity access circuits supplementing wired broadband access networks. However, a major issue in handling high-frequency bands such as the submillimeter and millimeter bands has been deterioration of circuit quality due to rain attenuation and the resulting degradation of operating efficiency. In order to deal with this issue, the authors proposed a multipoint-to-multipoint (MP-MP) FWA system using a mesh topology that organically combines point-to-point (P-P) wireless links, and quantitatively showed a diversity effect obtained on the mesh network to demonstrate the validity of the system. The proposed system was recommended for use as F.1704 by the ITU-R (International Telecommunication Union-Radiocommunication Sector), which promotes research into standardization of wireless communications and prepares recommendations. In this paper, we give theoretical evaluations of the diversity effect that formed the core of the recommendation, and present evaluation examples based on real data obtained from outdoor test networks, to demonstrate the validity of the diversity effect in the proposed system. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(11): 61–70, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20334","PeriodicalId":100405,"journal":{"name":"Electronics and Communications in Japan (Part I: Communications)","volume":"90 11","pages":"61-70"},"PeriodicalIF":0.0,"publicationDate":"2007-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/ecja.20334","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80740587","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

A multicast protocol avoiding unnecessary data forwarding with source distinction in mobile ad hoc networks 一种多播协议，在移动自组织网络中避免了不必要的源区分数据转发

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-05-25 DOI: 10.1002/ecja.20382

Motoki Shirasu, Yasuhiro Tsutsui, Takeshi Murakami, Iwao Sasase

{"title":"A multicast protocol avoiding unnecessary data forwarding with source distinction in mobile ad hoc networks","authors":"Motoki Shirasu, Yasuhiro Tsutsui, Takeshi Murakami, Iwao Sasase","doi":"10.1002/ecja.20382","DOIUrl":"10.1002/ecja.20382","url":null,"abstract":"In this paper, we improve On-Demand Multicast Routing Protocol (ODMRP), which is a multicast routing protocol for Mobile Ad hoc Network (MANET), and propose a new protocol decreasing the number of data forwarding without deteriorating communication reliability. The proposed protocol avoids unnecessary data forwarding by distinguishing each multicast source at every Forwarding Group (FG) Node used in ODMRP. Moreover, the proposed protocol utilizes Support Group (SG), which also distinguishes each multicast source, in order to retain substitute routes without any redundant data forwarding. Therefore, the proposed protocol can avoid deteriorating communication reliability. We evaluate the performance of ODMRP, ODMRP with SG, and the proposed protocol, and we show that the proposed protocol can decrease the number of data forwarding compared with the conventional protocols. We also show that the proposed protocol can restrain the deterioration of packet delivery ratio within allowable range except the case where the number of multicast sources and receivers is extremely large. Furthermore, we show that the proposed protocol can mitigate the deterioration of packet delivery ratio caused by traffic congestion in the case where the number of multicast sources is large. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(11): 36–47, 2007; Published online in Wiley InterScience (www. interscience.wiley.com). DOI 10.1002/ecja.20382","PeriodicalId":100405,"journal":{"name":"Electronics and Communications in Japan (Part I: Communications)","volume":"90 11","pages":"36-47"},"PeriodicalIF":0.0,"publicationDate":"2007-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/ecja.20382","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78631237","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

DHT-based peer-to-peer search system using pseudo-candidate key indexing 基于dht的点对点搜索系统，使用伪候选键索引

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-05-25 DOI: 10.1002/ecja.20317

Yutaka Arakawa, Hiroya Minami, Masato Matsuo, Masayasu Yamaguchi, Hiroshi Saito

引用次数: 5

Applicability of analysis method for electromagnetic field radiated from UTP cable in the UHF band using 4-port network 四口网络UHF频段UTP电缆辐射电磁场分析方法的适用性

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-05-25 DOI: 10.1002/ecja.20391

Shuji Fujiishi, Hiroto Tamaki, Yasuhiro Ishida, Nobuo Kuwabara

{"title":"Applicability of analysis method for electromagnetic field radiated from UTP cable in the UHF band using 4-port network","authors":"Shuji Fujiishi, Hiroto Tamaki, Yasuhiro Ishida, Nobuo Kuwabara","doi":"10.1002/ecja.20391","DOIUrl":"10.1002/ecja.20391","url":null,"abstract":"When communication signals are transmitted at high speed on balanced cable (UTP cable), signals may leak from the cable and affect the reception of wireless signals. To evaluate this effect, the radiated electromagnetic field from the balanced cable is measured by using a 4-port network at 300 MHz or less. Although this method has the advantage that it can be used to analyze line constants, it is not clear whether it can be applied in an analysis at a frequency greater than 300 MHz. In this paper, the authors investigate the applicability of this method at frequencies up to 1 GHz. As a result, they discuss a method of using a 4-port network to represent telecommunication equipment for increasing precision and a balun for simulating this equipment and also discuss the dependency of this method on the number of subdivisions of one twist of the cable. From the results of actually evaluating the radiated electromagnetic field by using a 3-meter length of UTP cable, it was apparent that this analysis method using a 4-port network was effective for obtaining the trends exhibited by the characteristics of the radiated electromagnetic field at up to 1 GHz by obtaining the 4-port network parameters of the terminal equipment parts and dividing one twist of the cable into 80 parts. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(11): 25–35, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20391","PeriodicalId":100405,"journal":{"name":"Electronics and Communications in Japan (Part I: Communications)","volume":"90 11","pages":"25-35"},"PeriodicalIF":0.0,"publicationDate":"2007-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/ecja.20391","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73068477","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

Packet arrival interval (PAI)-based time synchronization 基于PAI (Packet arrival interval)的时间同步

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-05-25 DOI: 10.1002/ecja.20402

Akihiko Machizawa, Tsukasa Iwama, Hiroshi Toriyama

{"title":"Packet arrival interval (PAI)-based time synchronization","authors":"Akihiko Machizawa, Tsukasa Iwama, Hiroshi Toriyama","doi":"10.1002/ecja.20402","DOIUrl":"10.1002/ecja.20402","url":null,"abstract":"Recently, in the fields of network measurement and distributed control, synchronization accuracy of better than microsecond order is required. For highly accurate time synchronization, the skew (the variation of the clock rate) and the queuing delay in the packet switching network constitute problems. In this paper, Packet Arrival Interval-based time synchronization (PAI) is proposed. In the proposed system, based on the fact that the average arrival interval of the synchronized packets broadcast accurately at a certain interval is less likely to be affected by the queuing delay, the clock rate is accurately estimated. Also, the one-directional delay from the master to each client can be calculated accurately from prior knowledge of the constituent elements of the LAN. Wide-range synchronization is possible if the master is synchronized to GPS. An experiment confirms that synchronization accuracy of better than microsecond order can be realized even in the presence of cross traffic with a channel use rate of about 80%. In addition, the present system can be used even with small nodes such as a sensor network. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(11): 12–24, 2007; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/ecja.20402","PeriodicalId":100405,"journal":{"name":"Electronics and Communications in Japan (Part I: Communications)","volume":"90 11","pages":"12-24"},"PeriodicalIF":0.0,"publicationDate":"2007-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/ecja.20402","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80210888","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: 3

A study of IP routing stability for GMPLS-based next-generation backbone network 基于gmpls的下一代骨干网IP路由稳定性研究

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-05-25 DOI: 10.1002/ecja.20332

Atsushi Tagami, Teruyuki Hasegawa, Toru Hasegawa

{"title":"A study of IP routing stability for GMPLS-based next-generation backbone network","authors":"Atsushi Tagami, Teruyuki Hasegawa, Toru Hasegawa","doi":"10.1002/ecja.20332","DOIUrl":"10.1002/ecja.20332","url":null,"abstract":"GMPLS (Generalized Multi-Protocol Label Switching) is considered promising as the basic technology for forming the next-generation ISP (Internet Service Provider) backbone network. In an IP backbone network based on GMPLS, the optical layer and the packet layer are vertically integrated and operate in close collaboration. It is due to this collaborative operation of multiple layers that integrated network control such as path setting in the optical layer according to the IP traffic in the packet layer and fast recovery from faults is realized. However, there is a danger, due to the similarity of functions in the two layers or to mismatch of the parameters, that collaborative operation between layers may affect the stability of IP routing in the packet layer. This situation is mostly due to the fact that the time granularity in the change of path state in the optical layer is finer than that of the IP routing protocol processing in the packet layer. This paper discusses route stability in the packet layer during collaborative operation of layers. The situation is analyzed by simulation and a method of improving stability is proposed. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(11): 71–80, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20332","PeriodicalId":100405,"journal":{"name":"Electronics and Communications in Japan (Part I: Communications)","volume":"90 11","pages":"71-80"},"PeriodicalIF":0.0,"publicationDate":"2007-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/ecja.20332","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87607078","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

Modified calibration method for MUSIC method with an array antenna 改进的阵列天线MUSIC法标定方法

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-04-23 DOI: 10.1002/ecja.20398

Akimichi Hirota, Takehiro Miyamoto, Masayuki Nakano, Hiroyuki Arai

{"title":"Modified calibration method for MUSIC method with an array antenna","authors":"Akimichi Hirota, Takehiro Miyamoto, Masayuki Nakano, Hiroyuki Arai","doi":"10.1002/ecja.20398","DOIUrl":"https://doi.org/10.1002/ecja.20398","url":null,"abstract":"In this paper, we propose a modified calibration method to improve the accuracy of direction of arrival (DOA) estimation, and conduct simulations and experiments to verify the effectiveness of the proposed method. In a system for DOA estimation, because the accuracy of the DOA estimation is degraded by the mutual coupling among the antenna elements, these elements must be calibrated. Therefore, we propose a modified calibration method to implement these improvements while considering the mutual coupling among the elements and the manufacturing errors. We verify the effectiveness of the proposed method by simulations and improve the accuracy by about twofold compared to the conventional method in experiments. In addition, the estimation accuracy is degraded by changes in the directions of the angle of elevation and the angle of dip in the conventional method, but we demonstrate the ability to suppress degradation by applying the proposed method. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(10): 1– 13, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20398","PeriodicalId":100405,"journal":{"name":"Electronics and Communications in Japan (Part I: Communications)","volume":"90 10","pages":"1-13"},"PeriodicalIF":0.0,"publicationDate":"2007-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/ecja.20398","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91862571","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