Showing papers on "Wireless published in 1988"

Wireless network for wideband indoor communications

Abstract: The present invention relates to a wideband communication network using wireless radio transmissions either on a stand-alone basis or to supplement a hard-wired network. The exemplary network comprises (a) a plurality of transceivers (10-19) associated with separate users of the network; (b) optionally at least one concentrator (20, 21) associated with certain separate subgroups of wireless (14-19) and possibly hard-wired (10-13) transceivers for providing duplex operation; and (c) a central node (30), (i) capable of providing both duplex communications directly via a radio channel using radio links with certain subgroups of the transceivers and via a hard-wired connection with each optional concentrator, and (ii) for polling the needs of all transceivers and directing all packets of information from active transceivers through the central node and to the destined transceivers during each frame period. The network also preferably includes diversity and resource sharing techniques to provide added protection against channel impairments on an as-needed basis.

Remote control apparatus for electronic equipment

Abstract: An apparatus for remotely controlling electronic equipment such as a VTR using a remote telephone set. The electronic equipment has a timer reservation unit which causes the electronic equipment to start a predetermined operation at a predetermined time in accordance with externally inputted reservation information and to become inoperable after a predetermined period. The timer reservation unit includes an input unit, and a remote controller is coupled to the input unit of the timer reservation unit to perform wireless communication therebetween. The remote controller is constructed such that the reservation information is transmitted to the input unit of the timer reservation unit in response to a predetermined push button operation or dial operation of the remote telephone set.

Dual connection mode equipped communication control apparatus

Abstract: A facsimile machine including a data processing system for processing data to be transmitted and received data according to a predetermined manner, which system typically comprises a MODEM, a buffer and a CODEC. The facsimile machine includes two or more interface units dedicated for performing a wire communication function for communicating image data in a wire communication mode using a telephone network and a radio communication function for communicating image data in a radio or wireless communication mode using radio waves. The radio/wire switchable facsimile machine includes a switch which switchingly establishes the wire mode or the radio mode. In one embodiment, the switch is manually operated. In a second embodiment the switch automatically establishes either one of the wire and radio modes in accordance with the current status of a predetermined signal, typically an off-hook signal, which indicates whether the handset of a telephone unit is hooked or unhooked or whether the microphone of a radio set is hooked or unhooked.

Packet reservation multiple access for local wireless communications

Abstract: Packet reservation multiple-access (PRMA) allows a variety of information sources to share the same wireless access channel. Some of the sources, such as speech terminals, are classified as periodic and others, such as signaling are classified as random. Packets from all sources contend for access to channel time slots. When a periodic information terminal succeeds in gaining access, it reserves subsequent time slots for uncontested transmission. Computer simulations reveal that PRMA combines high bandwidth efficiency with low control complexity and the flexibility to accept information from a diversity of sources. It is considered a promising technique for wireless access to future telecommunications networks. >

Signal-transmission type production supervising system including IC card and wireless type interface unit

Abstract: In a production supervising system of a work, a wireless type production supervising data processing apparatus is mounted on the work. The wireless type production supervising data processing apparatus includes a wireless type interface unit, and an IC card. The IC card includes CPU, EEPROM for storing the production supervising data, ROM for storing the program data, and RAM capable of storing other data than the production supervising data. The wireless type interface unit includes antennas, a receiver, a transmitter, a demodulator connected to the receiver, and a modulator connected to the transmitter. During the production of the work, the production supervising data previously stored in EEPROM are read from the IC card and processed in the interface unit and thereafter transmitted from the interface unit toward the external data controlling apparatus.

Properties of a TDMA pico cellular office communication system

Abstract: The properties of a TDMA/TDD (time-division multiple-access/time-division duplex) pico cellular cordless telephone system using decentralized dynamic channel allocation and handover are presented. The system has 16 time-division time-duplex channels (slots) per carrier, each occupying 2 MHz. The TDMA frame is 16-ms long, and each slot has bits for synchronization, signaling and data. The data speed is suited for 32-kb/s speech codecs. Procedures have been developed for efficient and quick dynamic channel allocation and handover, using the fact that one single radio can simultaneously monitor or communicate on all 16 channels. Simulations for a specific six-storeyed building indicate that 16 channels can provide wireless communication for up to 30% of the telephones, and 32 channels for up to 100% of the telephones. Tests show that no time dispersion equalizers are needed, and that antenna diversity is effective against fading dips and time dispersion. >

Wireless intraoffice networks

Abstract: An overview of the existing and growing demands for wireless office information networks is provided, and the existing research activities are assessed in some detail The radio frequency (RF) and infrared (IR) communication technologies are examined as candidates for wireless intraoffice communications The available bandwidths, according to federal regulations and characteristics of the channel for RF communications, are given Digital narrow-band and wideband spread-spectrum RF communications are assessed in terms of supportable data rate or number of simultaneous users in one cell of a cellular architecture in an office environment Various limitations of IR communications are discussed and existing systems and architectures are reviewed

Wireless optical communication system

Abstract: A wireless optical short-range communication system adapted for use as an intercom system. The system can be used in fast food restaurants and similar commercial institutions. The communication system (Fig. 4) includes a base station (12) to interconnect via optical communication a group of substantially similar physically spaced-apart, remote units (14, 16). Each one of the remote units includes an optical emitter (33, 37) to transmit an optical message-carrying beam to the base station, and an optical receptor (35, 39) to receive an optical message-carrying beam from the base station. The base station includes a receptor (30) for receiving the optical beam transmitted by the optical emitters of all of the remote units, and an optical emitter (28) to relay the received optical beam to the optical receptors of all the remote units. The base station includes a clock arrangement for synchronizing the operation of the system in a time division multiplexing carrier arrangement, by providing individual discrete time slots for the transmission of the signals from the remote units to the base unit, and for the transmission of the signals from the base unit to the remote units.

Narrow band synchronized radio communication and alarm system

Abstract: A narrow band relatively ultra stable radio apparatus for communicating alarm or data signals from a radio transmitter device to a radio receiver device, which receiver or transmitter may be carried by individuals, or may be battery operated or fixed to other devices, such as smoke detectors or burglary sensors, or the like, wherein the transmitting device and the receiving device are both phase locked to a 60 Hertz power line signal either by direct connection or via a 60 Hertz voltage induced into said radio devices from nearby power lines to thereby provide a means to precisely synchronize the transmitting device radio carrier signal and/or digital clock stream with the receiving device to achieve very high signal transmission reliability is disclosed. The apparatus is capable of transmitting an alarm digital identification code or a digital message and the receiving devices may output a simple on-off signal indicating the presence of an alarm, or a digital message may be output to control an apparatus attached to said receiver. A novel timing oscillator synchronized to the household AC power line frequency via wireless induced voltage for real time synchronization of both the transmitter and the receiver is also disclosed.

Wireless communications in the automated factory environment

Abstract: The networking issues involved in the use of infrared communications in a factory environment are described. A brief history of the use of infrared and radio for indoor (factory environment) communications is given, and the physical infrared environment is reviewed. Topology and protocol alternatives are compared. >

Spread spectrum multiple access performance of orthogonal codes in fading multipath channels

Abstract: Indoor wireless communications (IWC) is an attractive alternative to wire-based local area networks. However, the indoor environment is characterized by fading multipath channels. Direct-sequence spread-spectrum techniques, with their inherent resistance to multipaths, are promising for IWC. To allow multiple users within a limited bandwidth, code division multiple access (CDMA) is needed. The authors analyze one relevant CDMA technique. A set of M-orthogonal sequences of length N is assigned to each of K users. The sequences consist of phase-modulated signals on the same carrier frequency. The bandwidth efficiency achieved over fading multipath channels is the presence of additive white Gaussian noise and multiple-access interference is determined. >

Deglitching means for digital communication systems

Abstract: In a digital wireless subscriber telephone unit for wireless connection with a base station which includes a modem processor whose signal is converted to an analog signal which is then upconverted and filtered to form an IF signal, a deglitching circuit for removing glitch spikes occurring during the transition periods from digital signals to analog signals comprising a timing system, a detector for detecting the transistion periods in order to control the timing system, and a mixer coupled to the output of a D/A converter to mix a blanking signal from the timing system with the analog signal received from the D/A converter during the transistion periods, whereby the output of the mixer is returned to an intermediate reference level.

Cellular telephone communication between hospitals and ambulances

Abstract: Cellular telephones provide a new means of wireless telephone communication. In an experimental design study comparing the clarity of receiving and transmitting communications with cellular telephones versus conventional emergency medical radio/microwave equipment, cellular telephones proved to be superior in all aspects of clarity and ease. Cellular telephones have numerous cost and equipment advantages over radio equipment and should replace conventional radio/microwave equipment for emergency medical communication in areas where reliable cellular telephone networks are available. This will improve an important facet of prehospital emergency care.

Simulation of a wireless PBX system for offices

Abstract: Presents a software real-time simulation model of an envisaged FDMA wireless PBX system, based on second-generation digital cordless telephones at 900 MHz. The initial results show that such a system is feasible and can support the required user densities in office buildings. The system performance was found to be adequate using between 2-6 transceivers per basesite, and between 9-20 basesites per floor for user densities of between 0.1 and 0.7 CTs per 20 m/sup 2/. It has been shown that an FDMA wireless PBX system will provide considerable installation and maintenance cost savings at higher user densities, when compared with a TDMA-based system. At lower densities the advantages of either approach are less clear, but if the number of basesites is critical in terms of system cost and performance, then again FDMA would appear to be the better approach to adopt. However, there are indications that a hybrid TDMA/FDMA solution would be optimum for future wireless PBX systems. >

Light wireless system

Abstract: PURPOSE:To shorten the distance between a wireless and a photodetection part and to improve the reliance of transmission by separating a photoelectric element which is the photodetection part receiving a light wireless signal from a receiver controlling a load. CONSTITUTION:In a wireless system having a satellite receiver 2 which collectively receives and processes many wireless signals from a wireless transmitter 1, a photoelectric element which photodetects the light wireless signals consisting of address data, control data, etc. from the wireless transmitter 1, a tuning circuit 4 for the carrier detection of the light wireless signal outputted from the photoelectric element and a base band conversion part 5 converting the output of the tuning circuit into a base band signal are provided in the satellite receiver 2. And the base band signal is connected by a signal line 6 which is wire-connected to the satellite receiver 2, and provides a receiver 7 having a specific address, which receives the base band signal from the satellite receiver 2 so that the transmission distance between the wireless receiver 1 and the photoelectric element can be shortened.

Properties and capacity of a TDMA micro cellular office communication system

Abstract: Properties of a time-division multiaccess (TDMA) microcellular cordless telephone system using dynamic channel allocation and hand-over are presented. The system has 16 time-division time-duplex channels (slots) per carrier, each occupying 2 MHz. The TDMA frame is 16 ms long and each slot has bits for synchronization, signalling, and data. The data speed is suited for 32 kb/s speech codecs. Procedures are developed for efficient and quick dynamic channel allocation and hand-over, using the fact that a single radio can simultaneously monitor or communicate on all 16 channels. Simulations for a specific six-storey building indicate that 16 channels can provide wireless communication for up to 30% of the telephone and 32 channels for up to 100% of the telephones. Slot synchronization between adjacent systems is desirable, but not necessary. A modest echo control is needed on the trunk level interface to the PABX or PSTN (public service telephone network), if two wire transmission is used. Tests show that no time-dispersion equalizers are needed and that antenna diversity is effective against fading dips and time dispersion. >

Wireless type detector

Abstract: PURPOSE: To discriminate and display also an abnormality generating position by converting a received pulse signal into an inherent binary code corresponding to a sensor number by a reproducing detector, reading out the binary code by a decoder to drive a relay and displaying the sensor number of the sensor detecting the abnormality on a display lamp. CONSTITUTION: The received pulse signal is converted into the inherent binary code corresponding to the sensor number of one of sensors 11A to 11C by the reproducing detector 23, the binary code is read out by the decoder 24 to drive the relay 25 and abnormality detection is displayed on the display device 26. The inherent binary code is converted into the sensor number of the corresponding sensor by a display lamp code converter 27, a lighting address in the display lamp 29 is calculated by a driving circuit 28 and the sensor number of the sensor detecting the abnormality is displayed on the display lamp 29. Since the abnormality detecting position in addition to the display device 26 generating the abnormality alarm can be displayed on the display lamp 29 by using the sensor number allocated to each sensor on the receiver 20 side arranged on a separated position, the place of the abnormality detecting sensor can be immediately known and the corresponding processing can be quickly executed. COPYRIGHT: (C)1990,JPO&Japio

Multi-chamber dealing type air-conditioning machine

Abstract: PURPOSE:To facilitate the change of the commanding site of concentrated control and maintain the designing property of an air-conditioning machine, by a method wherein the transmission of operating command or stopping command for all of indoor machines from a wireless remote control unit to a control unit, connected either one of input terminals connected to respective indoor control unit, is permitted. CONSTITUTION:The transmission and reception of an operation control signal is effected through connecting lines 13-15 while the outdoor control unit 9a of an outdoor machine 9 receives the signals of the operating conditions from respective indoor control units 10a-12a of respective indoor machines 10-12 and memorizes them. The signals of the operating conditions of respective indoor machines 10-12 are transmitted from a wireless transmission and reception control unit 19, transmitting signals in accordance with the condition of that time to respective indoor machines 10-12, to a wireless remote control switch 20. When a chamber or a site, to be controlled through concentrated control, is to be changed, the change is effected by only connecting the wireless transmission and reception control unit 19 to the input terminals 17, 18 of the indoor machines 11, 12 in the objective chamber or place whereby two sets of remote controllers are connected to the indoor machine and the obstruction for the designing property of interior may be eliminated.

Electric equipment equipped with wireless remote controller

Abstract: PURPOSE:To obtain practicability by the non-crystal silicon solar battery of a small area in a wireless remote controller large in a consuming power by reducing the area of the solar battery and charging by an irradiating energy from a suitable light source in an electric equipment. CONSTITUTION:When the wireless remote controller 4 having the non-crystal silicon solar battery 3 is inserted to the storing part 2 of a video tape recorder 1 and stored, a push in switch 5 is depressed, a the light source such as a while fluorescent lamp or an LED array is lighted and a visible ray of 10mw/cm is radiated to the solar battery 3 opposite to the light source 6. In this case, as the light source 6, a visible light source having a main light emitting part in 350nm-700nm. Then, at the time of irradiating the light of the white fluorescent lamp of 10mw/cm , the carbon lithium secondary battery 8 of the electric capacity of 1.3mAh with 2V can be charged for 1.2hour.

Limits of Radio Communication — Collaborative Transmission Over Cellular Radio Channels

Abstract: Communication by the radiation of electromagnetic waves — radiocommunication — is potentially the simplest and most flexible means of transmitting information over distances of more than a few metres. A transmitter, a receiver, and two antennas is all that is needed. Its flexibility lies in that it is wireless — pun intended! — especially if either the transmitter, or the receiver (or both) are mobile, when radio is the only feasible means of communication. But this very convenience and flexibility also makes radio the interesting and challenging field of endeavour that it is in practice. The difficulty is the all-pervasive transmission medium. Radio waves can propagate — as air-waves, space-waves, and so on — to many places where they are unwanted, whereas “wire” communication is guided (normally) only to where it is required. More subtly, the purpose of communication is to put people in contact, by means of suitable connecting arrangements and protocols. This element of organisation is built in to wire communications, if only because of the need to provide a transmission medium between all those who may wish to communicate; often it has been overlooked or neglected in the case of radiocommunication.

Position measurement for radiolocation mobile station

Abstract: PURPOSE:To achieve a higher accuracy even when the state of radio wave propagation is measured, by receiving a return radio wave from a radiolocation mobile station with a specified wireless base station from among distance measuring signals transmitted in a time series from a plurality of wireless base stations. CONSTITUTION:To measure positions of radiolocation mobile stations M, return radio waves 1i, 2i and 3i from the radiolocation mobile stations M for three ratio waves 10, 20 and 30 which are oscillated to the radiolocation mobile stations M from a plurality of wireless base stations 1, 2 and 3 are all received with any one (specified wireless base station) of the wireless base stations, for example, wireless base station 1 and then, distance measuring signals with the wireless base station 1 are collated in delay based on a transmission sequential control system and a reception sequential control system to calculate distances from the wireless base stations 1, 2 and 3. Measurement data at the wireless base stations 2 and 3 excluding the wireless base station 1 are collected to the wireless base station 1 through telephone circuits 1L, 2L, 3L and the like to perform an analysis based on three measurement data thereby enabling further upgrading of measuring accuracy.

Wireless headphone system

Abstract: PURPOSE:To attain a wireless headphone by mounting a transmitter to an earphone terminal or a headphone terminal of an audio, radio or video equipment (AU equipment). CONSTITUTION:A transmitter unit (A) is connected to an earphone or headphone terminal of an AU equipment and a receiver (B) built in the wireless headphone is used to receive it in radio. The operating frequency of radio wave is selected as FM band, FM modulation is applied to the modulation system and the transmission power is selected in the range of the article 4 of the radio wave law (a remarkably weak radio wave in compliance with the ordinance of the Ministry of Posts and Telecommunications radiated from a radio station). The concrete range is in compliance with the article 6 of the enforcement regulations of the radio wave law. Thus, the operating range in use is widened without any remolding of the main body of the AU equipment.

A simple electronic interface for wireless chemical data communications

Abstract: 91. Bits and pieces, 37. A brief note on a simple electronic interface for wireless chemical data communications.