Personal Handy Phone Research Articles

Electromagnetic environments in roadways of underground coal mines and a novel testing method

The electromagnetic environment of laneways in underground coal mines is an important area for the design of new electronic products, as well as a fundamental space for mine monitoring, surveillance, communications and control systems. An investigation of electromagnetic interference in coal mines is essential for the enhancement of performances of these systems. In this study, a new field method is provided in which radiated emission tests in coal mine laneways have been carried out. We conclude that: 1) the wiring motor vehicles can radiate interference with a bandwidth up to 1 GHz and with an amplitude 10 dBμV/m higher than the background noise; 2) the PHS (Personal Handy phone System) mobile communication system can cause interference 40 dBμV/m higher than the background noise; 3) an interference 25 dBμV/m higher than the background noise can be generated during the communication at a working bandwidth of 48.8 MHz; and 4) power cables, battery vehicles as well as mechanical and electrical dong rooms have little effect on the electromagnetic radiation environment in coal mine tunnels.

ウェアラブル生体情報記録システム

A wearable bioinformation recording system has been developed for monitoring health conditions, daily living activities and heart function of elderly person. A tri-axis accelerometer attached to the elderly person can simultaneously measure dynamic and static acceleration forces. The heart rate, respiration rate, activity, posture and behavior are detected from the measured acceleration forces. These data are automatically transmitted to the host computer every hour, via a Personal Handy Phone (PHS). The host computer makes a graphic chart from these data. The elderly person's immediate family, caregiver or doctor can download the graphic chart to an internet mobile phone. When a heart discomfort is felt, the elderly person pushes the transmission switch on a wearable sensor, which sends the phonocardiogram (PCG) waveforms derived from the dynamic acceleration force of the prior two minutes and the waveforms for two minutes after the switch is pushed, directly to the host computer. The PCG is stored to the host computer. The doctor can download the PCG to the smart phone and monitor graphically.The developed system is not only applicable to at-home solitary elderly people, but could also be useful for monitoring hospital patients.

IEEE 802.11 wireless LAN implemented on software defined radio with hybrid programmable architecture

This paper describes a prototype software defined radio (SDR) transceiver on a distributed and heterogeneous hybrid programmable architecture; it consists of a central processing unit (CPU), digital signal processors (DSPs), and pre/postprocessors (PPPs), and supports both Personal Handy Phone System (PHS), and IEEE 802.11 wireless local area network (WLAN). It also supports system switching between PHS and WLAN and over-the-air (OTA) software downloading. In this paper, we design an IEEE 802.11 WLAN around the SDR; we show the software architecture of the SDR prototype and describe how it handles the IEEE 802.11 WLAN protocol. The medium access control (MAC) sublayer functions are executed on the CPU, while the physical layer (PHY) functions such as modulation/demodulation are processed by the DSPs; higher speed digital signal processes are run on the PPP implemented on a field-programmable gate array (FPGA). The most difficult problem in implementing the WLAN in this way is meeting the short interframe space (SIFS) requirement of the IEEE 802.11 standard; we elucidate the potential weakness of the current configuration and specify a way of implementing the IEEE 802.11 protocol that avoids this problem. This paper also describes an experimental evaluation of the prototype for WLAN use, the results of which agree well with computer-simulation results.

Tracking individual travel behaviour using mobile phones without information from base stations

Data collection methods that use mobile phones have been developed for tracking, monitoring, and analyzing travel behaviour. Previous methods using a Personal Handy Phone System (PHS) assumed that the location data of base stations were known. This paper shows a positioning method for a mobile object when base station location data are unavailable. Instead of base stations, signal strength vectors (reference vectors) are observed at many places in a target area. Mobile objects also observe a signal strength vector (target vector). A similarity index of reference and target vectors is used to calculate the location of a mobile object. This method tracked the ambulatory behaviour of tourists in an urban setting.

A new intelligent bed care system for hospital and home patients.

An intelligent bed-care system has been developed for monitoring patient movements and behavior in the hospital and at home in order to prevent injuries from falls, a major problem in health care facilities. Falls, as well as patient activity immediately preceding falls (i.e. exiting the bed), are especially dangerous when infusion extubation also occurs. This new system detects in-bed infusion fluid leaks, bleeding due to infusion-tube pullout, and urine resulting from incontinence. It employs stainless steel tape and wire noncontacting electrodes, several linear integrated circuits, and a low-power, 8-bit single-chip microcomputer The electrodes are installed between the bed mattress and sheet to record changes in an always-present alternating current (AC) voltage, which is induced on the patient's body by electrostatic coupling from a 100-V, 60-Hz alternating current power line around the bed. The microcomputer uses changes in the induced alternating current voltage to detect the patient's movements before and after leaving the bed, as well as any fluid leakage. The microcomputer alerts the nursing station, via the nurse call system or personal handy phone (PHS), that the patient is in an active state; has a dangerous posture on the bed; is contaminating the sheet due to leaking, bleeding or incontinence; or is out of bed.

Tracking Individual Travel Behavior Using Mobile Phone

Tracking type data collection methods using mobile phone have been developed for monitoring and analyzing individual travel behavior. Previous methods using PHS (Personal Handy phone System) assumed that the location data of base stations were known. This paper shows a location positioning method of a mobile object when the location data of base stations are not available. Instead of base stations, signal strength vectors (reference vectors) are observed at many places in a target area. A mobile object also observes a signal strength vector (target vector). The similarity index of a reference vector and a target vector is used for calculating the location position of a mobile object. This method is applied to tracking travel behavior of tourists in Kobe Kitano area.

Radiation Area Monitoring by wireless-communicating Area Monitor with Surveillance Camera

Aiming at a dose reduction and a work efficiency improvement for nuclear power plants that have high dose regions, we have developed our system of wireless-communicating Area Monitor with Surveillance Camera, and have performed an on-site test. Now we are implementing this Area Monitor with Surveillance Camera for a use as a TV camera in the controlled-area, which enables a personal computer to simultaneously display two or more dose values and site live images on the screen. For the radiation detector of this Area Monitor System, our wireless-communicating dosimeter is utilized. Image data are transmitted via a wireless Local Area Network (LAN). As a test result, image transmission of a maximum of 20 frames per second has been realized, which shows that this concept is a practical application. Remote-site monitoring also has been realized from an office desk located within the non-controlled area, adopting a Japan's wireless phone system, PHS (Personal Handy Phone) for the transmission interface.

Experimental results on indoor electromagnetic wave absorber using magnetic wood

The purpose of this paper is to propose a new type of indoor electromagnetic wave absorber using magnetic wood. This magnetic wood has good electromagnetic wave absorbing characteristics, a low specific gravity, a wood texture and other wood characteristics and can be easily processed. Electromagnetic wave absorbing characteristics were measured for four types of magnetic wood. The sandwich-type magnetic wood demonstrated the best wave absorbing characteristics among the four types of magnetic wood that were studied. The experimental results showed that the proposed indoor electromagnetic wave absorber can be used to suppress the transmission and reception of cellular phone and Personal Handy Phone System (PHS) signals and can be used as a cross protection for indoor wireless Local Area Networks (LAN). This wood can be processed for use in furniture, building materials, and other applications.

An analysis of higher‐order of a GaAs FET depending on IMD source impedance and its application to a design of low‐distortion MMIC power amplifiers

AbstractAlthough the π/4 phase shift modulation schemes used in quadrature phase shift keying (QPSK) are important approaches to ensuring efficient frequency usage in digital portable telephone systems, they also require linearity of the power amplifiers, they also require linearity of the power amplifiers, which is an undesirable constraint from the standpoint of efficiency. In this work, we describe a unified approach to this problem based on the idea that distortion can be effectively decreased by creating dips or “bumps” in the intermod characteristics, due to the dependence of the adjacent channel power (ACP) leakage on input power. For the special case of an impedance Zes connected to the gate of a FET, we use Volterra series to quantitatively demonstrate how the appearance of such dips or bumps is related both to Zes and to the fifth intermod (IM5). We then show analytically that when these dips or bumps are generated effectively, they can suppress IM5. Finally, we show that the resulting decrease in intermodulation distortion and improved efficiency make this method useful in the design of MMIC power amplifiers used in Personal Handy Phone (PHS) service. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 85(4): 10–21, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.1100

Material Design for Application to High Performance LCDs.

Liquid Crystal Display(LCD) is a high performance tool for displaying many kinds of information. Application of LCD is diversifying to notebook PC, monitor display, TV and reflective type of PDA and personal handy phone. To achieve these performance for several applications of LCD, development of new materials has been investigated. Color photoresist is used for color filter production. Negative and positive type of transparent photoresist are applied for leveling and overcoating layer of LCD process, and further used for spacer materials. For the next generation of alignment layer, photo-alignment material is also investigated. Dimerization of chalcone moiety showed good alignment characteristics for liquid crystals and good LCD performance.

Multiple paths protocol for a cluster type network

Nowadays we can access the Internet by carrying a portable computer and using wireless communication. The wireless network with personal handy phone system (PHS) and portable cellular telephone has only rates of tens of Kbps to a few Mbps. Compared with the cable network, the transfer rate cannot generally satisfy a highly developed communication service such as large file transfer and real-time communications. This paper proposes a protocol, SHAKE, for sharing multiple paths in a cluster type network that is a kind of LAN in which some mobile hosts temporarily connect mutually. SHAKE provides the functions for composing a cluster type network, and dispersing traffic efficiently by measuring transfer rate and round-trip time. As a mobile host has only a low transfer capacity for individuals to communicate with the outside, if whole capacities of other hosts which compose a cluster type network are shared, we can get larger transfer capacity and satisfy the required communication services. Copyright © 1999 John Wiley & Sons, Ltd.

Cell size extending effect of the personal handy phone system by means of delay spread control techniques

Cell size extending effect of the personal handy phone system by means of delay spread control techniques

A remote monitoring system for patients with implantable ventricular assist devices with a personal handy phone system.

The usefulness of a remote monitoring system that uses a personal handy phone for artificial heart implanted patients was investigated. The type of handy phone used in this study was a personal handy phone system (PHS), which is a system developed in Japan that uses the NTT (Nippon Telephone and Telegraph, Inc.) telephone network service. The PHS has several advantages: high-speed data transmission, low power output, little electromagnetic interference with medical devices, and easy locating of patients. In our system, patients have a mobile computer (Toshiba, Libretto 50, Kawasaki, Japan) for data transmission control between an implanted controller and a host computer (NEC, PC-9821V16) in the hospital. Information on the motor rotational angle (8 bits) and motor current (8 bits) of the implanted motor driven heart is fed into the mobile computer from the implanted controller (Hitachi, H8/532, Yokohama, Japan) according to 32-bit command codes from the host computer. Motor current and motor rotational angle data from inside the body are framed together by a control code (frame number and parity) for data error checking and correcting at the receiving site, and the data are sent through the PHS connection to the mobile computer. The host computer calculates pump outflow and arterial pressure from the motor rotational angle and motor current values and displays the data in real-time waveforms. The results of this study showed that accurate data on motor rotational angle and current could be transmitted from the subjects while they were walking or driving a car to the host computer at a data transmission rate of 9600 bps. This system is useful for remote monitoring of patients with an implanted artificial heart.

Cell size extending effect of the personal handy phone system by means of delay spread control techniques

Cell size extending effect of the personal handy phone system by means of delay spread control techniques

High-Quality and High-Speed Wireless Multimedia Transmission Technologyfor Personal Handy Phone System

The Personal Handy-phone System (PHS), developed as a PCS, has been very widely accepted. This system offers many benefits as the infrastructure of the mobile data communication services that are expected to be available soon with the popularity of nomadic computing. Data communication systems based on PHS and some applications are proposed in this paper. One of the key technologies, an error control scheme, is also introduced. Three kinds of possible system configurations are discussed as a data communication platform for PHS. One of them has an ARQ function which corrects all errors that occur in the propagation path. Conventional application software on nomadic computers can be used in the mobile environment because this ARQ function is installed as a lower layer protocol. The introduced system connects all mobile computers to all servers that are on the networks which include ISDN, the conventional analog PSTN, cellular networks and PHS networks.

An HBT MMIC power amplifier with an integrated diode linearizer for low-voltage portable phone applications

This paper gives a detailed description of a novel linearization technique using a transistor base-collector junction diode. The novel linearization technique effectively improves the gain compression and phase distortion of the heterojunction bipolar transistor (HBT) with no additional dc consumption, leading to highly efficient linear amplification of the /spl pi//4 DQPSK modulation signals. An AlGaAs/GaAs HBT monolithic microwave integrated circuit (MMIC) linear power amplifier was fabricated using the novel linearization technique for the handsets used in the 1.9 GHz Japanese Personal Handy Phone System (PHS). The fabricated HBT MMIC power amplifier exhibits an output power of 21 dBm and a power-added efficiency as high as 37% at an operation voltage of 2.7 V. At this rated output power, the adjacent channel power rejection in /spl plusmn/600 kHz offset frequency bands is -55 dBc and the error vector magnitude is 4.3%. This measured linearity is well within the PHS standard.

Understanding linearity in wireless communication amplifiers

This paper investigates the linearity of active devices and amplifiers that have modulated input signals. We describe an implementation of a mathematical technique for calculating spectral regrowth due to the nonlinear amplification of modulated signals typically used in wireless communication systems. This technique only requires knowledge of the single-tone gain and phase data as a function of input power and can be applied to any modulated signal given (a) the device or amplifier characteristics do not change significantly over the bandwidth of the input signal and (b) the modulation frequencies are much less than the carrier frequency. Verification of the mathematical technique is presented using examples of measured and calculated spectra for /spl pi//4-differential quadrature phase shift keying (DQPSK) personal handy phone system (PHS) and code division multiple access (CDMA) Offset-QPSK personal communication system (PCS) modulation schemes. This calculation technique is essential in determining fundamental tradeoffs between device performance (linearity, output power, gain, and power-added efficiency) and device bias conditions and load impedance.

An offset-free LPF for π/4-shift QPSK signal generator

With progress of on-chip digital signal processing capability, analog signal processing circuit blocks associated with A-to-D converters (ADCs) and/or D-to-A converters (DACs) are required to satisfy increasingly stringent performance criteria. For example, low-pass filters (LPFs) with low dc offset for anti-aliasing and/or smoothing are required. Conventional on-chip LPFs such as switched-capacitor filters and active-RC LPFs exhibit offset voltages of tens of millivolts depending on specific circuit architecture. These offset voltages are too large for some applications. Also, low-voltage operation implies low offset to maintain dynamic range. This paper describes an intrinsically offset-free LPF for use with a /spl pi//4-shift QPSK signal generator for the Personal Handy Phone System (PHS).

Estimations and evaluations of radiation patterns of personal handy phone systems by numerical electromagnetics code‐2 (NEC2)

AbstractTo verify that the electromagnetic analysis system NEC2 is effective for the development and design of the second generation digital cordless telephone investigated for use in the frequency band of 1.9 GHz. Two types of personal handy phone models with metal housing and plastic housing were fabricated and measurement and analysis by NEC2 were carried out for radiation patterns. The analysis results were found to agree with the measured results in regard to the absolute gain and shape. For the metal housing model, examples of the procedures were presented for modeling the housing by wire grids or surface patch elements. It was shown that the analysis results agree well with the measured results. It was also found that the radiation pattern of the plastic housing model is only slightly affected by the housing material. By realizing the installed circuit as an analytical model, estimations and evaluations of the radiation pattern are possible by means of NEC2. As a result, NEC2 is effective for the analysis of the radiation pattern of personal handy phone systems at 1.9 GHz.

Protocol and network control technology for personal mobile data communication

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.