Electronics and Communications in Japan (Part I: Communications)最新文献_第9页

Path loss prediction model for the over‐rooftop propagation environment of microwave band in suburban areas 郊区微波波段屋顶上传播环境的路径损耗预测模型

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-01-01 DOI: 10.1002/ECJA.20333

N. Kita, W. Yamada, A. Sato

{"title":"Path loss prediction model for the over‐rooftop propagation environment of microwave band in suburban areas","authors":"N. Kita, W. Yamada, A. Sato","doi":"10.1002/ECJA.20333","DOIUrl":"https://doi.org/10.1002/ECJA.20333","url":null,"abstract":"It is desirable that the method used for outdoor path loss estimation at microwave frequencies be one for which a worldwide consensus can be obtained through an ITU-R international standard. In this paper, a path loss prediction model for over-rooftop propagation environments is proposed for suburban areas. This model is based on the propagation mechanism explained by using the geometrical optics and consists of the direct wave region, the reflected wave region, and the diffracted wave region. The boundary points of these regions can be determined uniquely from the antenna height and building environment and all regions are continuously connected. Hence, high-precision estimation of the path loss can be estimated from the short-distance line-of-sight region to the far-field non-line-of-sight region. The proposed model is useful for channel design of microwave-band wireless access systems. Further, the method contributes to the ITU-R international standardization described above. Finally, it is shown that the measured path loss and the value estimated by the present model agree well at 2.2, 5.2, and 19.4 GHz. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(1): 13–24, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20333","PeriodicalId":100405,"journal":{"name":"Electronics and Communications in Japan (Part I: Communications)","volume":"1 1","pages":"13-24"},"PeriodicalIF":0.0,"publicationDate":"2007-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78591630","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: 32

Element‐localized Doppler STAP (Space Time Adaptive Processing) for clutter suppression in automotive forward‐looking RADAR 用于汽车前视雷达杂波抑制的单元局部多普勒STAP(时空自适应处理)

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-01-01 DOI: 10.1002/ECJA.20221

T. Inaba

{"title":"Element‐localized Doppler STAP (Space Time Adaptive Processing) for clutter suppression in automotive forward‐looking RADAR","authors":"T. Inaba","doi":"10.1002/ECJA.20221","DOIUrl":"https://doi.org/10.1002/ECJA.20221","url":null,"abstract":"In forward-looking radars such as automotive radars, it is necessary to suppress the reflected undesirable signal (clutter) from such objects as the ground surface (especially hills), guard rails, and buildings, in order to detect moving targets ahead. When using a pulse-Doppler filter (PDF), which is the conventional method for clutter suppression, separation is difficult when the velocity of the target relative to the clutter is small. In this paper, as a high performance clutter suppression method for such low-velocity targets, we propose element-localized Doppler space time adaptive processing (ELD-STAP), which includes a PDF in the preprocessing, and which uses an array antenna. In the proposed ELD-STAP, only the PDF output corresponding to the Doppler frequency breadth of the clutter, predicted from the speed of the vehicle on which it is mounted, is selected for applying STAP, and hence the dimension of the data vector, which is the greatest difficulty in the application of STAP, can be reduced. By reducing the dimension of the data vector, not only the computation load, but also the number of cells that must be referenced to estimate the clutter correlation matrix (called secondary cells), can be reduced. Computer simulation reveals that the proposed ELD-STAP yields an improvement factor better than that provided by the combination of PDF and multibeam forming (MBF). © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(1): 77–89, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20221","PeriodicalId":100405,"journal":{"name":"Electronics and Communications in Japan (Part I: Communications)","volume":"21 1","pages":"77-89"},"PeriodicalIF":0.0,"publicationDate":"2007-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83500037","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

Estimation of lightning location from single station observations of sferics 从单站观测资料估计闪电位置

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-01-01 DOI: 10.1002/ECJA.20329

I. Nagano, S. Yagitani, M. Ozaki, Y. Nakamura, K. Miyamura

{"title":"Estimation of lightning location from single station observations of sferics","authors":"I. Nagano, S. Yagitani, M. Ozaki, Y. Nakamura, K. Miyamura","doi":"10.1002/ECJA.20329","DOIUrl":"https://doi.org/10.1002/ECJA.20329","url":null,"abstract":"A system for lightning location from single station observations has been developed for localizing lightning (distance and direction) at rather short distances (several hundred kilometers). In this system, a vertical component of the electric field and two horizontal components of the magnetic field of the VLF wave of the sferics are observed. The sferics are usually observed as a pulse train. The first pulse is used for estimation of the direction. The second and subsequent pulses are multiple reflections between the ionosphere and the ground. The differences in arrival time of these reflected waves are determined by the propagation distance between the ground and the ionosphere. The reflection altitude of the ionosphere and the horizontal distance to the lightning location are estimated from the arrival time difference of more than two pulses. In this research, the electromagnetic pulses radiated from the lightning are first analyzed by the full wave method, considering the ionosphere, free space, and the ground, in order to evaluate the location estimation method. The lightning location is estimated by calculating the space discharge sferics waveform at the observation point. Observations were also carried out with the lightning location system for estimation of lightning locations. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(1): 25– 34, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20329","PeriodicalId":100405,"journal":{"name":"Electronics and Communications in Japan (Part I: Communications)","volume":"96 1","pages":"25-34"},"PeriodicalIF":0.0,"publicationDate":"2007-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76988241","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: 15

Statistical evaluation of transmission performance degradation originating with cross-phase modulation 由交叉相位调制引起的传输性能下降的统计评估

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-01-01 DOI: 10.1002/ECJA.20306

S. Norimatsu, Seiichi Akai

引用次数: 1

Influence of TCP congestion control on multifractal nature of network traffic TCP拥塞控制对网络流量多重分形特性的影响

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-01-01 DOI: 10.1002/ECJA.20277

H. Doi, T. Matsuda, M. Yamamoto

{"title":"Influence of TCP congestion control on multifractal nature of network traffic","authors":"H. Doi, T. Matsuda, M. Yamamoto","doi":"10.1002/ECJA.20277","DOIUrl":"https://doi.org/10.1002/ECJA.20277","url":null,"abstract":"The multifractal nature of traffic volume is known to have significant influence to queuing behavior in network nodes. In the Internet, TCP traffic, which is the major traffic flowing through the Internet has been reported to have multifractal nature. To control the effect of the multifractal nature, the origin of the multifractal nature in TCP traffic needs to be explained. However, it is still unclear what part of TCP control mostly affects the multifractal nature. In this paper, we focus on TCP congestion control from the viewpoint of multifractal nature of generated traffic. We investigate “what component of TCP congestion control mechanism affects multifractal nature of generated traffic?” Our simulation results show that Retransmission Time-Out mechanism plays an important role for multifractal nature of TCP traffic. In addition, our results show that avoiding occurrence of Retransmission Time Out is the best approach to improve TCP performance, i.e., throughput degradation, LRD, and multifractal nature. Random Early Detection (RED), based on the fact that Retransmission Time Out should be avoided, to improve TCP performance are also reasonable from the viewpoint of LRD and multifractal nature. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(1): 68–76, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20277","PeriodicalId":100405,"journal":{"name":"Electronics and Communications in Japan (Part I: Communications)","volume":"52 1","pages":"68-76"},"PeriodicalIF":0.0,"publicationDate":"2007-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90680070","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

Some techniques for avoiding dips of antenna radiation efficiency on improved Wheeler method 改进惠勒法避免天线辐射效率下降的一些技术

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-01-01 DOI: 10.1002/ECJA.20323

N. Ishii, T. Kaneko, M. Miyakawa

引用次数: 5

Congestion control with multiple congestion control policy for large bandwidth‐delay‐product networks 基于多拥塞控制策略的大带宽延迟产品网络拥塞控制

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-01-01 DOI: 10.1002/ECJA.20310

Kentaro Saito, K. Igarashi, T. Ihara, A. Miura

{"title":"Congestion control with multiple congestion control policy for large bandwidth‐delay‐product networks","authors":"Kentaro Saito, K. Igarashi, T. Ihara, A. Miura","doi":"10.1002/ECJA.20310","DOIUrl":"https://doi.org/10.1002/ECJA.20310","url":null,"abstract":"Recently, broadband applications such as data grids and IP-Storage Area Network have been proliferating. In these applications it is necessary to exchange large amounts of data quickly over networks with a capacity of several gigabits per second. For this purpose, various kinds of congestion control have been proposed for use in such broadband networks. In these kinds of congestion control, the idle bandwidth of the network can be used quickly by increasing the communications speed at the time of communications. On the other hand, complicated forms of congestion are generated in the network. Therefore, when these kinds of congestion control and the existing TCP communications coexist, the existing TCP communication is strongly compressed. In the present paper, TCP with multiple congestion control policies (TCP-MP) is proposed in order to make swift use of idle bandwidths in the network. In TCP-MP, an additional congestion control policy is provided in addition to using a form of congestion control similar to that in conventional TCP, so that information on the variation of the RTT between the transmitter and the receiver can be used to estimate the idle bandwidth of the network and the communications speed is chosen in such a way that the idle bandwidth is used up. Hence, it is possible to quickly use the bandwidth of the network within the range in which the existing TCP communications is compressed. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(1): 45–57, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20310","PeriodicalId":100405,"journal":{"name":"Electronics and Communications in Japan (Part I: Communications)","volume":"IA-15 1","pages":"45-57"},"PeriodicalIF":0.0,"publicationDate":"2007-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84594704","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

A MAC proposal to IEEE802.11n high‐throughput WLAN for 20/40 MHz coexistence 针对20/40 MHz共存的IEEE802.11n高吞吐量WLAN的MAC提案

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2007-01-01 DOI: 10.1002/ECJA.20335

Y. Utsunomiya, T. Tandai, T. Adachi, M. Takagi

{"title":"A MAC proposal to IEEE802.11n high‐throughput WLAN for 20/40 MHz coexistence","authors":"Y. Utsunomiya, T. Tandai, T. Adachi, M. Takagi","doi":"10.1002/ECJA.20335","DOIUrl":"https://doi.org/10.1002/ECJA.20335","url":null,"abstract":"IEEE802.11-1999 Standard is widely known as a standard of WLAN and it has a number of amendments and supplements such as 802.11a, 802.11g, and 802.11i and also those under work in the current activities by the task groups (TGs). The one now attracting a great deal of attention is TGn, which is aimed at achieving high throughput. We are involved in this TGn standardization process. To achieve high throughput, MIMO technique is the main discussion point in the PHY layer in TGn. But another important point is the channel bundling method which extends the channel bandwidth from 20 MHz to 40-MHz. By doubling the channel bandwidth, the data rate can be increased. But when this channel bundling method is introduced, the question of how to cope with the legacy 20-MHz stations will arise. For this problem, we are proposing to control the 20-MHz and 40-MHz STAs by setting NAV to them in the MAC layer. This paper explains our coexistence proposal for the system where transmission in both 20-MHz and 40-MHz channel bandwidths is enabled. The performance is also examined to confirm the influence of applying our coexistence proposal. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(1): 1–12, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20335","PeriodicalId":100405,"journal":{"name":"Electronics and Communications in Japan (Part I: Communications)","volume":"95 1","pages":"1-12"},"PeriodicalIF":0.0,"publicationDate":"2007-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77192398","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

Theoretical evaluation of spectral efficiency and outage probability of TDMA multihop cellular systems TDMA多跳蜂窝系统频谱效率和中断概率的理论评估

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2006-12-13 DOI: 10.1002/ecja.20366

Koji Yamamoto, Atsushi Kusuda, Tsuyoshi Nakano, Susumu Yoshida

{"title":"Theoretical evaluation of spectral efficiency and outage probability of TDMA multihop cellular systems","authors":"Koji Yamamoto, Atsushi Kusuda, Tsuyoshi Nakano, Susumu Yoshida","doi":"10.1002/ecja.20366","DOIUrl":"10.1002/ecja.20366","url":null,"abstract":"<p>For TDMA cellular systems that introduced multihop transmission, the spectral efficiency and outage probability in a single-cell environment are formulated and evaluated numerically. By using approximations, the numerical evaluation is also conducted in an interference-limited multicell environment and compared to simulation results. In formulating these performances, the focus is on the common points of multihop transmission and symbol rate control, and a method similar to the performance evaluation method of rate-adaptive TDMA cellular systems is applied. In particular, the opposite effects of multihop transmission on the spectral efficiency are explicitly considered. In a single cell environment, instead of lowering the spectral efficiency somewhat by the introduction of multihop transmission, the cell coverage satisfying the allowable outage probability could be clearly expanded. A multicell environment could be implemented with cell reuses with a smaller allowable outage probability resulting from the introduction of multihop transmission. Consequently, an improved spectral efficiency is expected. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(4): 1–10, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20366</p>","PeriodicalId":100405,"journal":{"name":"Electronics and Communications in Japan (Part I: Communications)","volume":"90 4","pages":"1-10"},"PeriodicalIF":0.0,"publicationDate":"2006-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/ecja.20366","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76606475","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

Performance evaluation of media access control protocols using an algorithm generating graphs for effect estimation of hidden terminals 媒体访问控制协议的性能评估，使用生成图的算法来估计隐藏终端的效果

Electronics and Communications in Japan (Part I: Communications) Pub Date : 2006-12-13 DOI: 10.1002/ecja.20343

Tetsuya Shigeyasu, Hiroshi Matsuno, Norihiko Morinaga

引用次数: 5