Basic microwave properties of magnetic photonic (MPC) and degenerate band edge (DBE) crystals are investigated mathematically and experimentally. Two dimensional and three dimensional models are considered demonstrating the very high sensitivity and field growth associated with these crystals. A major part of the paper deals with the development of realistic anisotropic periodic structures using a combination of layers constructed from thin film frequency selective surfaces, alumina, titanate and calcium vanadium garnet (CVG) materials. Measurements for antenna applications demonstrate and validate the theoretical performance of the MPC and DBE crystals. The latter part of the paper will present an exciting and promising development relating to microwave circuit applications. Specifically, a novel dual-line printed circuit is presented to emulate propagation in anisotropic media. As such, the MPC and DBE phenomena can be realized using very simple printed circuits (coupled lines). Lastly, physically small printed antennas and arrays based on the coupled transmission lines are presented.

Despite the extensive literature on current conveyor-based voltage-mode universal biquads with single input and multiple outputs, no filter circuits have been reported to date which simultaneously achieve all of the advantageous features: (i) employment of only one differential difference current conveyor (DDCC), (ii) employment of only two grounded capacitors, (iii) employment of only three resistors, (iv) simultaneous realization of voltage-mode low-pass, band-pass, and high-pass filter signals from the three output terminals, respectively, (v) no need to employ inverting type input signals, and (vi) no need to impose component choice.

This paper proposes pilot-based channel quality reporting for orthogonal frequency division multiple access/time division duplex (OFDMA/TDD) systems with cochannel interference. In the proposed method, a terminal reports his channel quality in multiple subbands to base station (BS) using channel reciprocity of TDD systems. The terminal transmits uplink pilot signals in the subbands with different transmit power which is inversely proportional to the subband-based interference power. The BS can obtain knowledge of the terminal's received signal-to-interference-plus-noise power ratio on subband basis, measuring the pilot signal power. In performance evaluation, accuracy of channel quality reporting and amount of uplink signalling are examined. From numerical results, it is found that the proposed method becomes effective as the number of subbands and terminals for channel quality reporting increases.

China has experienced fast growth in mobile communications. Now, China is the world largest mobile communication country with about 500 million users. Wide applications of mobile communications are giving strong pull to the research and development on the broadband wireless communication technology to meet the fast growing demand for high speed access into the information infrastructure. This makes the R&D on wireless technology play great role in the Chinese High-Tech program. This paper will review the key project--FuTURE (Future Technology for Universal Radio Environment)--development of the 863 program, which represents the Chinese efforts towards IMT-advance. Taking some works done in the Tsinghua National Laboratory for Information Science and Technology as examples, the paper will show what has been made in China on the broadband wireless technology, including the trial network in Shanghai.

We investigated the radio propagation characteristics for line-of-sight (LOS) inter-vehicle communication (IVC) at 60 GHz on an actual road with an undulating surface. Radio propagation tests between two moving vehicles were carried out on a test course. From this, it was found that the measured received power on the actual road and the results calculated for a flat road approximately follow logarithmic normal distributions. To investigate this phenomenon in detail, a propagation test between two stationary vehicles on a road was performed. Furthermore, calculations using geometrical optics taking road undulation into consideration demonstrated that undulation in the road can cause variations in the received power that follow a logarithmic normal distribution. Finally, the received power for moving vehicles on an undulating road was calculated using the model.

This letter proposes a group-based distributed air index (called GDI) using two-leveled groups by partitioning the identifiers of data items to reduce the size of the index. GDI provides both global and local views of data items and multiple pointers to data items in a single access to an index. Simulation results show that GDI outperforms the existing index in terms of multiple data access, energy conservation and data waiting time.

Due to the discontinuity of packet based traffic, the user terminals in next generation mobile telecommunications systems will be equipped with sleep mode operation functions for power saving purpose. The sleep mode parameters should be appropriately configured so that power consumption can be sufficiently decreased while packet queue length and packet delay are restricted within a demanded level. This paper proposes an adaptive sleep mode parameter configuration scheme which is able to jointly optimize the inactivity timer and sleep period in response to the variation of user traffic arrival pattern. The optimization target of this scheme is to minimize mobile terminal power consumption while ensuring that the mean downlink packet queue length do not exceed a certain threshold. Results of computer simulations prove that, the presented approach perfectly manages packet queue length restriction, packet delay control and power saving in a wide range of user packet inter-arrival rates both in single- and dual-service scenarios.

In conventional road-vehicle communication systems, user terminals in the vehicles have to directly connect to wireless access points (APs). However, vehicle speeds are so fast that the channel condition between the terminals and the APs constantly changes because of changing path loss and time-varying fading. In this paper, to compensate for such deterioration, we propose to reduce the relative speed between the terminals and the APs by an inter-vehicle packet relay technique. If a terminal can send data via other vehicles running at lower speeds, the relative speed will decrease, which suppresses the dynamic range of path loss and deterioration by fading. We, first, validate our method by a numerical analysis using a statistical path-loss model. The numerical analysis verifies that our method is able to suppress deterioration caused by path loss and time-varying fading. However, in the numerical analysis, geometric propagation of paths is not considered; instantaneous and rapid loss changes are not considered. Therefore, we evaluate our method by computer simulations using a geometric propagation model. In the simulations, phase difference between multiple paths and loss fluctuation within one frame duration affect the performance. From the results of the simulations, we validate our method. Furthermore, we investigate the combination of our method and the selection diversity technique, which can suppress channel fluctuation and may enhance the performance of our method. Moreover, we measure interference in the overlapped zone between two AP areas. From the measurement, we show that our packet relays do not cause a problem in interference between areas.

To create a next-generation mobile satellite communication system that offers large communication capacity, the onboard antenna system must be a multi-beam system consisting of a light weight 20-m class reflector and a light weight 100-beam class antenna feed system. We clarify that the antenna gain decrease created by the reflector surface distortion expected in orbit is relatively large. This paper presents a deformed antenna pattern compensation method that minimizes circuit scale. Validity of the proposed method is confirmed by antenna pattern calculations and experiments on a fabricated array-fed reflector antenna.

This paper describes a beam scanning antenna that consists of a movable dielectric plate loaded onto a microstrip comb-line antenna. This type of antenna uses a mechanical system and so offers a simple structure and low cost. The main beam direction of the proposed antenna is changed by moving the dielectric plate. The guide wavelength of the microstrip line was measured at the quasi-millimeter wave band (20 GHz) when moving the dielectric plate to investigate the possibility of beam scanning. The proposed antenna was fabricated to experimentally demonstrate its principle operation. A possible beam scanning angle of 20 degrees was confirmed.

We propose an N-channel power-compensated reconfigurable optical add/drop multiplexer (ROADM) based on using fiber Bragg gratings (FBGs). Both tunable FBGs and wavelength-fixed FBGs are used in this ROADM. By using the dual-pass amplification scheme with two pieces of erbium doped fibers, an 8.0 dB optical net gain has been achieved with a gain variation less than 0.5 dB for each add/drop/pass-through channel. System performance was studied for a four-WDM-channel 10 Gb/s100-km lightwave transmission trial network and bit error rate of 10-9 is observed for the 50 km added signal, 100 km pass-through signal and 50 km dropped signal at -18.3, -19.4 and -18.9 dBm received power, respectively. Only 1.1 dB of power penalty was observed compared to the back-to-back transmission.

Generalized Multi-protocol Label Switching (GMPLS) technologies are expected a key technology that creates high-performance Internet backbone networks. There were many GMPLS interoperability trials. However, most of them reported the successful results only. How to set up a trial network and how to test it was generally not discussed. In this paper, as a kind of tutorial, detailed GMPLS field trials in the National Institute of Information and Communications Technology (NICT) Kei-han-na Info-Communication Open Laboratory, Interoperability Working Group (WG) are reported. The interoperability WG is aiming at the leading edge GMPLS protocol based Inter-Carrier Interface that utilizes wide-bandwidth, cost-effective photonic technology to implement IP-centric managed networks. The interoperability WG is a consortium for researching the GMPLS protocol and advancing a de facto standard in this area. Its experimental results, new ideas, and protocols are submitted to standardization bodies such as the International Telecommunications Union-Telecommunication standardization sector (ITU-T), the Internet Engineering Task Force (IETF), and the Optical Internetworking Forum (OIF). This paper introduces the activities of the interoperability WG; they include a nationwide GMPLS field trial using the JGN II network with multi-vendor, multi-switching-capable equipment and a GMPLS multi routing area trial that used a multi-vendor lambda-switching-capable network.

We propose a new label recognition system for photonic label switching using self-routing of labels. Binary-coded labels in on-off keying format are considered. The system consists of an all-optical demultiplexer (DeMUX) and an address recognition unit (ARU) consisting of tree-structured switches. The system uses self-routing propagation of an indication bit controlled with address bits. The indication bit is placed in advance of the address bits in the label. In DeMUX, all-optical switches in a configuration of Mach-Zehnder interferometer with semiconductor optical amplifiers (SOA-MZI) are controlled by the indication bit pulse to separate each of the label bits. The indication bit pulse is routed to the destination output port corresponding to the code of the address in ARU. It is shown that all the binary number codes can be recognized with this system. The operation principle is verified by numerical simulation using coupled-mode theory and a rate equation. Moreover, the switching crosstalk is also evaluated.

This paper presents a novel stereophonic acoustic echo canceling scheme without preprocessing. To accurately estimate echo path keeping the high level of performance in echo erasing, this scheme uses two filters, of which one filter is utilized as a guideline which does not erases echo but helps updating of the other filter, which actually erases echo. In addition, we propose a new filter dividing technique to apply to the filter divide scheme, and utilize this as the guideline. Numerical examples demonstrate that the proposed scheme improves the convergence behavior compared to conventional methods both in system mismatch (i.e., normalized coefficients error) and Echo Return Loss Enhancement (ERLE).

This paper investigates the prospects and challenges of hierarchical optical path networks. The merits and issues of introducing higher order optical paths are elucidated. State of the art of the key enabling technologies are demonstrated including hierarchical optical cross-connect switch architectures, hierarchical optical path network design algorithms, a newly developed waveband filter, and waveband conversion technologies.

This paper reports a novel design in Photonic Crystal Fibers (PCFs) with nearly zero ultra-flattened dispersion characteristics. We describe the chromatic dispersion controllability taking non-uniform air hole structures into consideration. Through optimizing non-uniform air hole structures, the ultra-flattened zero dispersion PCFs can be efficiently designed. We show numerically that the proposed non-uniform air cladding structures successfully archive flat dispersion characteristics as well as extremely low confinement losses. As an example, the proposed PCF with flattened dispersion of 0.27 ps/(nmkm) from 1.5 µm to 1.8 µm wavelength with confinement losses of less than 10-11 dB/m. Finally, we point out that full controllability of the chromatic dispersion and confinement losses, along with the fabrication technique, are the main advantages of the proposed PCF structure.

A communication means is presented for patients with amyotrophic lateral sclerosis in totally locked-in state who are completely unable to move any part of the body and have no usual communication means. The method utilizes changes in cerebral blood volume accompanied with changes in brain activity. When a patient is asked a question and the answer to it is 'yes', the patient makes his or her brain active. The change in blood volume at the frontal lobe is detected with near-infrared light. The instantaneous amplitude and phase of the change are calculated, and the maximum amplitude and phase change are obtained. The answer 'yes' or 'no' of the patient is detected using a discriminant analysis with these two quantities as variables. The rate of correct detection is 80% on average.

A press-fit connection is a solderless electrical connection technology, which utilizes the mechanical contact force generated between through-holes on a printed circuit board (PCB) and terminals with a width slightly larger than the through-hole diameter. This technology has been widely noted recently as a measure against the "Lead Free Requirement" of materials comprising electric/electronic devices, especially in the area of automobile connector. For the application of this technology to automobile connectors, we have to take into account the severe requirement, such as (1) the adaptation to wider through-hole diameter tolerance range and (2) the establishment of connection reliability for the various PCB surface treatments. As a result, we have determined the minimum and maximum contact forces satisfying the long term connection reliability and designed the terminal shape, which has been refined the N-shape cross section developed before, by using three dimensional finite element methods (FEM). Furthermore, we have developed a new type of hard tin plating on terminals, thus preventing the scraping-off of tin during the insertion process, that could result in a short-circuit on the PCB, for the Organic Solderability Preservative (OSP) treated PCB. The press-fit connector for the automobile airbag Electronic Control Units (ECUs) we developed has been able to transfer to the mass-production phase successfully from August 2005.

The transmit power of Ultra Wideband (UWB) is limited in short range communications to avoid the interference with existing narrow-band communication systems. Since this limits UWB communication range, this paper proposes a novel relay scheme that uses shared frequency repeaters for impulse UWB signal relay to improve system range. After considering possible problems with the repeater, in particular the coupling interference between the input and output and relay-delay, a switching control method is proposed that offers short relay-delay and suppresses the coupling interference at the repeaters. With respect to the proposed relay scheme, Pulse-Position-Modulation (PPM) UWB-based signal relay is evaluated by analyzing its BER performance using the point-to-point transmission link model.

The traffic with asymmetry between uplink and downlink has recently been getting remarkable on mobile communication systems providing multimedia communication services. In the future mobile communications, the accommodation of asymmetric traffic is essential to realize efficient multimedia mobile communication systems. This paper discusses asymmetric traffic accommodation in CDMA/FDD cellular packet communication systems and proposes its efficient scheme using an adaptive cell sizing technique. In the proposed scheme, each base station autonomously controls its coverage area so that almost the same communication quality can be achieved across the service area under the asymmetric traffic conditions. We present some numerical examples to demonstrate the effectiveness of the proposed scheme by using computer simulation. The simulation results show that, under asymmetric traffic conditions, the proposed scheme can provide fair communication quality across the service area in both links and can improve total transmission capacity in the uplink.