bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tentative reduction of analog cellular facsimile communication time
Authors: Uchiyama Hiroki , Kokaji Harumi , Kasuga Masao , Kagawa Tetsuya 
Published: July 2007

AbstractVarious studies have been done, mainly from the viewpoint of improving image deterioration on G3 facsimile transmission using analog cellular channels. This paper discusses communication time with analog cellular facsimile transmission using ITU‐T's error correction mode (ECM). the communication state graph proposed shows its transmission state. Then the protocol of standard ITU‐T's ECM is studied and an effective fall‐back method is proposed. the goal is to use a 9600 bps modem rate, which is not used in analog cellular facsimile transmission, and then an effective fall‐back, e.g., from 9600 bps to 7200 bps, is performed in the case of poor line conditions. This method allows the communication time in analog cellular facsimile transmission to be shortened. Results of field experiments have revealed that a shorter communication time can be achieved with the proposed method than with the conventional transmission method.
Technique for estimating electromagnetic field distributions in and around buildings using wire‐grid approximation
Authors: Maeda Yuji , Murakawa Kazuo , Yamane Hiroshi , Tokuda Masamitsu 
Published: July 2007

AbstractThe technology to derive analytically the electromagnetic field distribution inside and outside a building by the electromagnetic interference caused by electronic equipment and from external illegal CB has been an important subject of study for establishment of the protection of damages to equipment.In this paper, the building as a complex configuration is approximated by a wire‐grid model considering its steel frame construction. the electromagnetic field distribution inside and outside the model is analyzed numerically by the moment method so that the distribution of the electromagnetic interference around the building is derived.First, for a model of a simple building, the calculated and measured electric field intensity values are compared. They agree within a maximum deviation of 3 dB in the frequency range of 30 MHz to 1 GHz. the effectiveness of the calculation method and the resonance characteristics of the building model have become clear.Next, an actual building (Telecommunication Center Building) was modeled and the calculated and measured values of the electric field intensity in the model were compared. the calculated and measured results agreed within a maximum deviation of 5 dB in the frequency range of 30 to 200 MHz so that the validity of the present estimation method was confirmed. Also, the frequency characteristics of an actual building have become clear.
Even harmonic resonant class E tuned power amplifier without RF choke
Authors: Iwadare Minoru , Mori Shinsaku , Ikeda Kazunaga 
Published: July 2007

AbstractA method for designing an amplifier that does not need an RF choke coil is proposed. This is accomplished by adding a shunt capacitor to a class E amplifier with a shunt inductor; this creates class E switching where higher harmonics are induced in the inductor‐fed input waveform. A design method is derived by performing an analysis of the circuit assuming load current is sinusoidal. Because the switch current is smaller than that of conventional class E amplifiers (with the same output power), the losses due to the series saturation resistance of the switch device are greatly reduced for the proposed amplifier. A 96‐percent RF conversion efficiency for 2 W of output power was obtained in experiments using a 2‐MHz switch using the proposed design.
Configuration and characteristics of an interference cancellation system using a pilot signal for radio channel estimation
Authors: Fukasawa Atsushi , Sato Takuro , Kawabe Manabu , Sato Sinichi , Sugimoto Hiroki 
Published: July 2007

AbstractThis paper proposes a new configuration for an interference cancellation system for spread‐spectrum communications and will verify its performance. In the proposed system, a pilot signal with a known code is spread modulated without altering the data and sent to the common reverse link. Blind deconvolution is avoided because the characteristics of the radio channel are determined from the received pilot signal. The new configuration is simpler and offers improved interference cancellation.A filtering system is proposed for the estimated and the correlated signals using a time‐variant model to alter the characteristics of the radio channel along with the operation of the personal station. A sequential configuration system is proposed for interference cancellation (simply called cancellation). This is considered to be equivalent to the basic configuration that has been previously proposed, yet it further simplifies the configuration. The cancellation system is based on the system stated above. The path‐diversity combination of the delay wave and the data and the amount of interference on the destination and interfering channels are estimated, and interference from other channels is removed.This paper discusses, first, the estimation system for time‐variant multipath radio channels and, second, the configuration of sequential cancellation and its management. Based on the above, a cancellation system is proposed and the effectiveness of the proposed system is verified.
A differential positioning scheme with a single satellite to be incorporated into mobile communications
Authors: Yabumoto Yasuyuki , Katayama Masaaki , Yamazato Takaya , Ogawa Akira 
Published: July 2007

AbstractThe case in which the radio determination capability is integrated into a mobile satellite communication system is investigated and a positioning scheme is proposed which operates with a single satellite. In the proposed scheme, each mobile terminal is designed to be equipped with the minimum additional function for positioning, aiming at the integration of communication functions with low cost. It is not necessary to transmit the correction signal for range error although a differential technique is applied to improve positioning accuracy. To evaluate the feasibility of the proposed scheme, we calculate the horizontal dilution of precision (HDOP) and available area taking account of the time period required for positioning and satellite altitude.
Design and evaluation for the mobile packet communication system using continuously allocated small zones
Authors: Takaba Sadao , Sakai Sei‐Ichirou , Sekine Tomiyoshi , Hamabe Kojiro 
Published: July 2007

AbstractA new land‐mobile packet communication system is proposed in which continuously allocated small zones are used. This system is an expansion of a spot‐covered digital communication system, the application of which to mobile navigation is currently being advanced.In this system, data for driving guidance and general‐purpose data are assumed to be transmitted. The communication control of this system is designed and a hierarchical system configuration and efficient communication protocol are proposed. Also, the effectiveness is confirmed through system evaluation by an experimental model which consists of two pieces of mobile equipment and two roadside stations and by computer simulation.
Surface error measurements of large reflector antennas by phase retrieval holography—an application of extrapolation algorithm
Authors: Nishibori Toshiyuki , Hirabayashi Hisashi , Kobayashi Hideyuki , Murata Yasuhiro , Shimawaki Yutaka , Nomura Takuya 
Published: July 2007

AbstractThis paper investigates the phase retrieval holography (PRH) method using the Misell algorithm for measuring the surface error of a large reflector antenna. PRH is a technique that does not require phase measurement. The algorithm is investigated experimentally and the estimation errors are evaluated quantitatively using measurement simulation. First, it is shown that estimation errors can be reduced using an initial aperture distribution calculated by ray‐tracing. The measurement resolution is improved by applying an extrapolation algorithm to the Misell algorithm. Finally, the surface error of a Cassegrain antenna with an aperture of 64 m to resolution of about 4.1 m in the aperture plane was measured by receiving a test signal from a geostationary satellite (frequency: 1.545 GHz). As a result of the experiment, the surface error of 1.57 mm RMS and measurement reproducibility of 0.54 mm RMS were obtained and it was confirmed that this method is effective as a simple surface measurement method.
Stimulated brillouin scattering threshold representing bit‐error ratio degradation in single‐mode optical fiber transmission
Authors: Hayashi Yoshihiro , Ohkawa Norio , Ito Takeshi 
Published: July 2007

AbstractAchieving maximum repeater spacing in optical fiber transmission systems is compromised by the input power limit due to stimulated Brillouin scattering (SBS). In digital transmission, SBS causes bit‐error rate degradation. The calculation method for the SBS equation under steady state in a single‐mode optical fiber has been established here; boundary conditions and actual environment are both considered. A new SBS threshold has been proposed as the input optical power at which the backscattered SBS power equals the Rayleigh backscattering power at the fiber input end. Based on a detailed comparison with experimental results, it has been confirmed that the proposed threshold expresses accurately the bit‐error rate degradation due to the SBS; it is approximately 2.5 dB lower than the conventional threshold. Use of the proposed threshold makes accurate system design possible.
Loss probability in distributed‐type communication networks through semishortest routing–for connectionless services
Authors: Takase Juhro 
Published: July 2007

AbstractA number of logical networks with differing traffic characteristics need to be generated over a distributed physical network in order to deal effectively with future call types and service configurations that involve a range of basic situations. Also, each call must examine one connectionless‐type logical network by selecting the logical network that conforms to fundamental conditions based on the connection stipulations. The shortest route is selected through each switching node for each of the individual header data blocks (HB) of the call. The semishortest routing scheme that permits an increase in the number of relay stages is chosen, notably when a block occurs. Using this scheme, the HB loss probability between the originating and destination nodes is maintained reliably at about Nminld2 where the HB discard rates for each node are d equally and each originating and destination node is sufficiently distant from each other. Nmin is the minimum number of relay stages between the originating and destination nodes, l equals 2 in grid‐type networks, and l equals 3 in honeycomb‐type networks. The number of relays on the route between the originating and destination nodes can be a maximum of 2Nmin. The loss probability can increase by controlling the maximum number of relay stages. If the number of relays is limited to Nmin + 2, the reliable maximum value of the loss probability is approximately Nmind. The minimum reliable value of the loss probability is maintained at a level Nminld2.
Interruption characteristics of distributed dynamic channel allocation with reuse partitioning and power control
Authors: Serizawa Mutsumu , Asakawa Shigeru 
Published: July 2007

AbstractDistributed dynamic channel allocation (DDCA) schemes are important because they allow flexible handling of variations in traffic. It has been clarified by simulation that better call‐loss and interference characteristics are obtained by combining reuse partitioning and transmission power control schemes. Channel allocation and interference in DDCA are formalized in this article. It is also shown that a lower limit can be established in the signal‐to‐interference ratio (SIR) degradation caused by interference accompanying calls to other stations when channel allocation is performed such that reuse partitioning is ideally realized simultaneously. It is shown that this lower limit is described by the SIR margin and reuse partitioning characteristics and power control schemes. In addition, it is shown that the degrees of degradation in SIR of the mobile station and the base station in conversation can be predicted in advance, including the case in which reuse partitioning may not be performed ideally.
Multicast routing method in optical switching networks
Authors: Harai Hiroaki , Murata Masayuki , Miyahara Hideo 
Published: July 2007

AbstractIn realization of high‐speed and broadband networks of the next century, expectations are toward optical switching and a linear lightwave network (LLN) is proposed as one of the possibilities. Using LLNs, this paper proposes a multicast routing system in which a tree structure is formed with no loop inside the network. In this way, the waste of bandwidth caused by transmission of signals to unintended destinations is avoided. The scheme in which the tree is settled dynamically in case of generation of a call is proposed and its function is evaluated through simulations. As the results, the possibility of the efficient use of the unused links and realization of call setup control of equitable terminals are shown. Further, because of inherent LLN characteristics, the generated call blockings are small and superior performance is achieved in comparison to the previously proposed methods.
Basic characteristics of timing synchronization with recursive least‐squares for digital mobile radio
Authors: Fukawa Kazuhiko , Suzuki Hiroshi 
Published: July 2007

AbstractThis paper describes high precision accurate estimation methods for phase and frame timing frequency by a least‐squares adaptive algorithm for high‐precision master‐slave mobile radio synchronization systems. First, the measurement process of the received timing signal edge in the forward link is described. Next, an estimation algorithm applying least‐squares is presented and its estimation error is obtained. Furthermore, it is shown that the third‐order estimation is superior to the second‐order estimation if the reference oscillator frequency in the slave changes linearly. Computer simulations and experiments numerically verified the theoretical results on the convergence state. A synchronization using a synchronization word transmitted every 20 ms is assumed. It is shown that frequency estimation can be estimated with a precision of 10−8in several ten seconds.
An airspace design and evaluation of enroute sector by air traffic control simulation experiments
Authors: Tofukuji Noriyasu 
Published: July 2007

AbstractIn the enroute air traffic control which controls the aircraft flying between airports, the broad area of airspace is divided into units called sectors. This paper describes the air traffic control simulation experiments considering the function expansion project of the Tokyo International Airport and discusses the evaluation of the airspace design for the enroute air traffic control sectors.First, the traffic volume after the function expansion is estimated. The result is compared to the already obtained result of experiments for the sector traffic capacity estimation in the present airspace. The sector for which the airspace redesign is needed is pointed out.Next, based on the evaluation criteria considering the control process, three trial plans (A, B, and C) for the airspace design are presented and examined by experiments. Based on the results of evaluation, the fourth trial plan (D) is presented, including a new control technique. It is shown that, by using that technique, the average traffic volume in the busiest hours anticipated after the function expansion can be controlled smoothly.
Protocol and network control technology for personal mobile data communication
Authors: Nakakuki Kazuo , Kuribayashi Shin‐Ichi 
Published: July 2007

AbstractIn tandem with a growing information society, personal communication service expansion is expected. Commercial service using a personal handy phone system (PHS) for speech communication started in July 1995. Because the demand for data communication service is on the rise, the need for a realization method is imperative. This paper studies protocol and network control technology with an eye on offering economical personal radio data communication service and clarifies the following.(1) To share equipment with a personal radio speech service, it is desirable for the interface between a radio base station and a network to be based on I interface. Authentication processing by an out‐channel is better, and sharing the equipment with personal radio speech communication will greatly reduce future costs.(2) After introduction of personal radio packet communication service, it is suitable for location registration, including that of speech terminals, to be done by packet.(3) To achieve both economy and wide applicability, a scheme in which service control node accessing at terminating exchange nodes is unnecessary is employed for basic call.(4) With the introduction of personal radio packet communication service, terminal information, such as transfer mode, is managed at service control nodes and useless connection processing is avoided.
Jitter transmission model and jitter power estimation in pointer processing for synchronous digital hierarchy
Authors: Ohtake Kohhei , Kasai Hiroyuki , Tsuboi Toshinori 
Published: July 2007

AbstractIn the synchronous digital hierarchy (SDH) pointer processing system, jitter is produced in the asynchronous interface operation. Especially, it is difficult to suppress the stuffing jitter since it contains a large amplitude ultra‐low‐frequency component. This kind of jitter deteriorates especially the quality of the image transmission. Thus, it is important to evaluate the jitter in the design of the pointer processing synchronous hierarchy.This paper considers, as the first stage, the general case where the jitters are included in the input signal as well as in the transmission/reception distribution clocks. The phase tracking condition in the SDH pointer processing synchronization system with the ternary phase control function by positive/negative stuffing is examined and the expressions for the generated jitters are formulated.A jitter transmission model is proposed based on the formulation. Then, under the assumption that the difference input jitter has the spectrum with the first‐order cutoff and exhibits the Gaussian distribution, estimation formulas are shown for the jitter power spectrum and the jitter power. Using the expression for the jitter power, the case of the single‐stage pointer processing synchronization system is estimated. The effect of the power and the bandwidth of the difference input jitter on the stuffing jitter power, which is the major factor for the transmission quality deterioration, is analyzed.
Geo2concentration dependence of nonlinear refractive index coefficients of silica‐based optical fibers
Authors: Wada Akira , Okude Satoshi , Sakai Tetsuya , Yamauchi Ryozo 
Published: July 2007

AbstractThe nonlinear refractive index coefficientn2dependence on the GeO2concentration in optical fibers is quantitatively shown for SiO2core fibers and GeO2‐SiO2core/SiO2clad fibers with Δ = 0.35–2.2% using an XPM measurement method where the phase change in the fiber of a probe signal caused by a pump signal is found from the delay self‐heterodyne spectrum. The GeO2concentration distribution which determines then2distribution in the fiber is not uniform, and the measuredn2is the average of the product of the localn2and the fourth power of the electric field in the fiber. In this work, this relationship of the measuredn2, the cross sectional distribution ofn2, and the electric field distribution in the fiber is used to define an effective GeO2concentration, ηeff. This effective GeO2concentration level is used to evaluaten2. The measuredn2increases proportionally to ηeffby the relationshipn2[x 10–20 m2/W] = 0.0552°eff[mol%] + 2.44. Furthermore, the measuredn2in the fiber agrees well with then2of bulk glass obtained a semiempirically for the nonlinear refractive index coefficient derived from linear refractive index data.
Design and performance of the fsa submarine optical amplifier system
Authors: Murakami Makoto , Takahashi Tetsuo , Aoyama Masaharu , Imai Takamasa , Sumida Masatoyo , Amemiya Masaki 
Published: July 2007

AbstractThe FSA submarine optical amplifier system (submarine fiber using optical amplifiers) has been developed. It can transmit signals up to 10 Gbit/s with a repeater spacing of 100 km. The submarine repeaters contain optical amplifiers for six line pairs to yield a maximum capacity of 60 Gbit/s. This paper describes its system configuration, the repeater configuration, and the fiber dispersion management scheme used to realize bit‐rate flexible transmission and in‐service monitoring.In long‐haul optical amplifier systems, since the amplified spontaneous emission noise from the optical amplifier is the main impairment limiting the transmission distance, an SNR design technique that takes this noise into account is developed. Finally, the results obtained after the commercial installation of this system in the Kagoshima‐Okinawa route (total length 905 km) are reported, including chromatic dispersion characteristics and SNR values at both 2.5 Gbit/s and 10 Gbit/s transmission. The effectiveness of the system design is verified through the demonstration of good transmission performance and the feasibility of in‐service monitoring.
Development of 128 optical distribution system of 150 chs am/qam hybrid signals
Authors: Fuse Masaru , Kudo Yoshiharu , Maeda Kazuki , Ohya Jun , Ishino Masato , Fujito Katsuyuki 
Published: July 2007

AbstractAn optical distribution system for providing CATV services to approximately 30,000 subscribers using a fiber‐to‐the‐curb (FTTC) system has been developed. This system distributes the optical signal to 128 paths for 90 carriers with a hybrid 150 channel signal which accommodates 60 AM signals and 90 16 QAM signals to provide both conventional service and future services. The development of low distortion and low chirp MQW 1.55 mm DFB‐LD is discussed and the zero distortion conditions for optical fiber amplifiers are verified in the investigation of the main parameters in the design of the system. To satisfy the system specifications, the signal wavelength is chosen to be 1561 nm, the input optical power is set to 6 dBm, and a two‐stage optical fiber amplifier structure is used. The results of transmission tests are shown to verify the performance of the system. Lastly, the potential for expansion of the optical distribution system is discussed.
Application of planar multibeam array antennas to diversity reception
Authors: Mano Shuji , Kimata Masayuki , Inagaki Naoki , Kikuma Nobuyoshi 
Published: July 2007

AbstractA method is proposed for constructing a diversity branch with each beam of a planar multibeam array antenna (MBAA), and its diversity reception characteristics are evaluated. The proposed method is a kind of directional diversity. If the beam‐forming network of the MBAA is lossless, each beam is orthogonal to the other so that a branch configuration with its correlation coefficient close to zero can be expected.With respect to a three‐element planar MBAA that has an easy hardware implementation, computer simulations assuming a Rayleigh distribution environment and an indoor diversity reception measurement with test antennas were carried out.The effectiveness of the method is confirmed as well as good agreement between the numerical results and the measurement results in the Rayleigh distribution environment. The diversity gain at the 1 percent value of the cumulative distribution by computer simulation is about 10, 13 and 14.5 dB for 2, 3 and 4 branches. Improvement of slightly less than 1 dB is expected for the addition of one extra branch.