Showing papers on "Wireless published in 1990"

Radio communication system and a portable wireless terminal

Abstract: This invention proposes a radio communication system including a plurality of radio terminals, a relay apparatus (including a plurality of base stations and an exchange station) connected to each radio terminal so that the radio terminals can interchange information from each other, and a data processing unit connected to the relay apparatus, each radio terminal having a circuit for inputting and outputting a voice signal and a circuit for inputting and outputting data whereby it can communicate with another radio terminals or with the data processing unit through the relay apparatus. The radio terminal of this invention further has a clock, and a circuit for storing a schedule inputted by the user thereby to automatically select a receiving mode such as a ringing mode or a nonringing mode in accordance with the contents of the schedule, the present time and so on.

Personal communications-a viewpoint

Abstract: A personal view of an extended concept of personal communications is discussed. The relationship between low-power digital cordless technology and some alternatives (analog cordless, digital mobile radio, and cellular mobile radio) is examined. Personal communication network (PCN) power requirements, circuit quality, level of network integration, and access to network intelligence (e.g. call forwarding, call transfer, and personal number calling) are emphasized. >

Antenna control for a wireless local area network station

Abstract: A local area network station (12) includes a transceiver (20) adapted to transmit and receive signals using electromagnetic radiation on a wireless communication link. The station (12) utilizes a CSMA/CD communications controller (22) in a CSMA/CA (collison avoidance) technique wherein deferred data frames are transmitted after a random number of backoff slots periods. A plurality of antennas (14, 16) is employed, with the antenna having the best receive conditions being selected for reception of a data frame. The antennas having a slotting control (200) which is synchronized with the backoff slotting to provide a short carrier detect time and hence high throughpout.

Wireless in-building telecommunications system for voice and data communications

Abstract: A wireless in-building telecommunications system for voice and data communications is disclosed having at least one node (101) arranged for linking to the PSTN (151) and at least one digital information source (153, 155, 157, 159) multiplicity of user modules (103) (UM's) linked to the node via a shared RF communications path (107). Each UM is coupled to a voice telephone instrument (127) and to one or more data terminals (165). The UM's communicate with the node by exchanging fast packets via the common RF path (107). The node also includes a fast-packet-switched mechanism controlled by a bandwidth allocating scheme to prevent collisions of packets as they are transmitted between the various units (101, 103) (nodes and/or user modules) that may be accessing the RF path (107). Also disclosed is a method for allocating the required bandwidth to each of the users of the common communications path in a wireless in-building telephone system. The invention provides for the combination of both voice and data in a single switch using a common packet structure. It allows for the dynamic allocation of bandwidth based on system loading. This includes not only bandwidth within the voice or data areas of the frame, but also between the voice and data portions. It also synchronizes the transfer of the data and the allocation of bus bandwidth.

Wireless integrated voice-data communication system

Abstract: A digital voice-data communication system having a base network control unit coupled to a plurality of fixed transceivers for providing communications to a plurality of portable sets. The base network control unit includes control means for permitting communication between the portable sets within the system, or between the portable sets and a larger external telecommunications network. The system employs frequency hopping, time division multiplexing and demand assigned multiple accessing to permit economy of fixed resources via multiple voice channels for each fixed station transceiver and relatively simple portable sets which may be hand held.

Spread-spectrum multiple-access performance of orthogonal codes for indoor radio communications

Abstract: Direct-sequence spread spectrum, with its inherent resistance to multipath, is a promising technique for indoor wireless communication. To allow multiple users within a limited bandwidth, code division multiple access (CDMA) is needed. The bandwidth efficiency of M-ary CDMA systems in fading multipath indoor radio channels is analyzed. It is shown that M-ary signaling improves the bandwidth efficiency significantly when compared to binary signaling. >

Distributed synchronization method for a wireless fast packet communication system

Abstract: A distributed synchronization method for a wireless fast packet communication system (100) is disclosed. The distributed synchronization method, according to the invention, provides for the combination of both voice and data in a single switch using a common packet structure. It allows for the dynamic synchronization of packets. This includes not only bandwidth within the voice or data areas of the frame, but also between the voice and data portions.

The digital cordless telecommunications common air interface

Abstract: Over the last ten years the development of cordless telephones in the UK has followed a logical path, from simple analogue instruments designed for domestic and small business use, through to the world's first digital cordless telecommunications system. The adoption of a common air interface for the digital cordless telecommunications system will expand its markets beyond those of conventional cordlessness, by encouraging the development of business cordless systems and public cordless access services (telepoint) that use a common personal handset

Microcellular mobile radio systems

Abstract: The long-term target is a universal system which will provide the man-in-the-street with integrated access to cellular, cordless, wireless PABX, paging and private mobile radio (PMR) type services, perhaps causing the biggest change in social habits and telecommunications service since Alexander Graham Bell's original invention of the telephone. The paper addresses some of the design aspects of microcellular networks, including topics such as cell types, handover issues, cellular infrastructure and interconnection, and radio link management

Wireless bistatic link intrusion detection system

Abstract: An intrusion detection system employing multiple bistatic microwave links and wireless means for remotely interrogating each link to provide alarm and status information at a central station. The central station includes a microprocessor for remotely adjusting the operating parameters of the microwave transmitters and receivers forming said links to increase the probability of intrusion detection and reduce the probability of false alarms.

Coding and optimum baseband combining for wideband TDMA indoor wireless channels

Abstract: Optimum baseband combining with coherent BPSK (binary phase-shift keying) or QPSK (quadrature phase-shift keying) is an attractive technique for wideband TDMA (time-division multiple-access) portable communication radio links in view of its ability not only to combat dispersive fading but also to cancel cochannel interference. The performance of such a scheme is investigated for data rates ranging from 1 to 20 Mb/s. It is shown that convolutional coding with soft-decision Viterbi decoding can be a viable alternative to increasing the space diversity order even in the absence of interleaving if the effective diversity order is sufficiently large. The radio link performance is evaluated for various combinations of transceiver and channel parameters. The cochannel interference level and the space diversity order are shown to affect the data rate beyond which QPSK is preferable to BPSK. >

Intelligent networking for digital cellular systems and the wireless world

Abstract: Current trends in wireless and networking technologies are reviewed, and the benefits and potentials that can result from intelligent networks and services incorporating both technology trends are addressed. The transition from analog to digital cellular transmission in public systems to support increased subscriber densities and provide enhanced services, the low-powered microcellular systems which will provide flexible services within buildings. and intelligent wireless networks that will enhance the mobility of both corporate and residential subscribers are discussed. >

Light/radio wave wireless composite system

Abstract: PURPOSE:To extend the range of optical remote controller operation by providing a 1st repeater and a 2nd repeater and applying optical/radio wave conversion and radio wave/optical conversion CONSTITUTION:An optical wireless signal radiated from an optical wireless transmitter 1 is received by a photodetection section 22 of the repeater 2 in a room 6, converted into a radio signal in the repeater 2 and a signal from a transmission antenna 28 is sent The radio wave is transmitted through a partition 5 and is received by a reception antenna 32 of a repeater 3 in other room 7, converted into an optical signal by the repeater 3 Then the signal is sent from a light emitting section 37 of the repeater 3 as an optical wireless signal, the optical wireless signal is received by a light receiving section 9 of a device to be controlled 8 Thus, even if there is the partition 5 between the optical wireless transmitter 1 and the device 8 to be controlled, the device 8 to be controlled is operated and the range of the operation of the optical remote controller is expanded

Packet transmission and switching in advanced wireless information networks

Abstract: The author looks ahead to third-generation wireless networking. The vision is a single set of standards that can meet a wide range of wireless access applications. Third-generation systems, in harmony with broadband integrated services digital networks, will use shared resources to convey many information types. A single network architecture will serve its users efficiently in many environments, including moving vehicles, indoor and outdoor public areas, residences, offices, and factories. A switching architecture referred to as a cellular packet switch, and a packet transmission technique referred to as packet reservation multiple access, are being studied. The author describes both techniques and shows how they can work together to meet the demands of third-generation wireless networking. >

Power saving circuit in a mobile device for wireless communication

Abstract: In a power-saving circuit in a mobile device for wireless communication with a fixed transceiver station, which mobile device has a reception and transmission circuit for sound and/or data signals and a power supply source with a battery or an accumulator, it being possible for the transmission power to be adjusted according to the distance between the device and the fixed transceiver station, the transmission power of the transmission circuit in the mobile device is adjusted according to the received field strength of the received signal, which is a useful signal modulated with a carrier frequency.

Wireless system signal line branching device for remote monitor control system

Abstract: PURPOSE:To eliminate the need for the increase in the number of wireless receivers unnecessarily even when two systems of signal lines are adopted and number of terminal equipments is increased by using a branching device so as to branch wireless system signal lines into the main system and the branch system CONSTITUTION:A signal detector 12 detecting a current mode signal on a wireless system signal line 38 of the main system between a wireless relay terminal equipment 34 and a wireless receiver X is provided and a branch output generation section is provided, which outputs a current mode signal to a wireless system signal line 38 of the branching system different from the main system based on the detection signal by the signal detection section 12 Since the wireless system signal line 38 is branched into the main system and the branch system by a branching device 10, when one system of wireless system signal line is branched into two systems, the system can cope with 2 systems of wireless relay terminal equipments 34 Thus, when signal lines are used for 2 systems and the number of terminal equipments is increased, it is not required to increase the number of wireless receives X unnecessarily

Apparatus for facsimile transmission

Abstract: A device is described which, by means of specially developed interfaces and operating systems, is capable of transmitting information items to a radio network which transmits the data by wireless means so that the facsimile transmission is received by all devices of the same type which are in each case in operation, and which, at the same time, also has all the functions of a normal device for facsimile transmission via the telephone network.

The design of a third generation personal communications system

Abstract: The author discusses the design of a spectrum efficient system for the third-generation wireless personal communications system. The focus is on the radio interface of the system. The author analyzes and compares the various alternatives and recommends a radio interface which is based on the direct-sequence code-division-multiple-access technique. The system supports up to forty voice channels in a 1.25 MHz bandwidth. With microcell technology, the recommended system achieves a system capacity of 13000 users per square kilometer per MHz. >

Transmission control method in wireless control system

Abstract: PURPOSE:To improve the transmission efficiency of a multiplex signal line by applying switching control to the reception mode and the transmission mode of a relay receiver of a control system in response to the processing state of a data of the system. CONSTITUTION:When a control switch 1a of an optical wireless transmitter 1 is operated, the same transmission data being an optical pulse is sent continu ously for plural frames, the transmission data is received by plural relay receivers 2 connecting to a controller 3 via a multiplex signal line l and the wireless transmitter 1 is constituted so that the same transmission data of plural frames is continuously sent for each transmission of one unit and after the wireless relay receiver 2 confirms the reception of the transmission data sent from the wireless transmitter 1, till the time starting the reception of the transmission data of the succeeding frame is reached, so long as an acknowledge signal from the controller 3 is not received, the mode is set to the transmission mode and the multiplex transmission control repeating the transmission to the controller 3 of the received transmission data is executed.

Wireless transmission control system

Abstract: PURPOSE:To improve the convenience at the time of the use by an end user by receiving and demodulating a data signal only sent from a wireless receiver having the registered ID code after the ID code transmitted from a wireless transmitter is registered and executing the remote control of a control object provided on a wireless receiver side. CONSTITUTION:The ID code of the wireless transmitter A is automatically registered to a wireless receiver B side only by operating an operating switch 1a of a wireless transmitter A to be registered like the ordinary control. After the ID code of either of the wireless transmitter A is registered, and after the registration of the ID code of another wireless transmitter A is received during the prescribed time, the control mode is automatically shifted, only the transmission data of the wireless transmitter A having the registered ID code is decoded, and the corresponded control object is remote-controlled. Thus, at a user side, besides the setting of the ID code, the wireless transmission system without needing the setting operation of the registration mode and with an easy operation can be obtained.

Wireless adapter for telephone set

Abstract: PURPOSE:To easily perform wireless speech by connecting a wireless adapter to an ordinary telephone set having no wireless function by providing an electrical connection part in which a telephone set main body side and a handset can be used in wire speech by connecting them to a fixed part and a movable part, respectively, and a radio transmission/reception circuit connectable by radio in a separated state. CONSTITUTION:The wireless adapter 1 is constituted of the fixed part 2 connected mechanically by connecting mechanisms 8a and 8b mutually and connected electrically by a connecting part 4 for wire speech, and the movable part 5. In the case of requiring speech separating the handset 7 from a telephone set main body 9 during a call, the transmission/reception signal of the handset 7 is transmitted to a cord (a), a handset connector 6, and a radio speech circuit 3b by separating the fixed part 2 and the movable part 5 by the connecting mechanisms 8a and 8b and the connecting part 4 for wire speech, and it is transmitted from the radio speech circuit 3b to a radio speech circuit 3a by radio communication, and is transmitted to the telephone set main body 9 via a cord (b) and a main body connector 10. In such a way, it is possible to switch the ordinary telephone set to a wireless telephone set by the wireless adapter 1.

Wireless pseudo call processor

Abstract: PURPOSE:To arbitrarily connect a processor to each repeater in a wireless channel controller, and to miniaturize the processor by setting a time division exchange which simulates wireless channel setting. CONSTITUTION:Each pseudo mobile station device 15 controls an outgoing call and an incoming call, confirms the connection of a channel, a controller 17 controls a time division exchange 13 to simulate the wireless channel setting and the pseudo mobile station device 15 to simulate the wireless line and to set a hand-off condition, thus functions are distributed, and further respective signals are digitized, time-divided, and multiplexed. Consequently by separating an A/D-D/A converter 11 and time-division multiplexing/demultiplexing circuit 12 from the other parts, and arranging them near a wireless channel controller 2 to be a device to be tested, the separated parts can be connected to the other parts by a single connecting cable. Thus the whole device can be miniaturized, and the connection to the wireless channel controller 2 can be simplified.

Wireless information transmission method.

Abstract: A method is proposed for wireless information transmission in which unoccupied transmission channels of radio services, for example television transmitters, are used. The method uses the channels of the radio services only while no transmission takes place. If transmission is started up, this is identified and the channel concerned is no longer used for radio transmission. Through band spreading, the transmission channel can be used for a large number of radio units simultaneously without them interfering with one another.

Performance of fast-frequency-hopping spread-spectrum multiple-access for indoor wireless communications

Abstract: Digital systems employing antenna diversity and noncoherent binary frequency-shift-keying modulation operating through an indoor radio multipath Rayleigh fading channel are investigated theoretically. The diversity technique of equal gain combining is considered. The frequency-hopping rate is assumed to be equal to the bit rate. Results show that the FFH systems are better able to counteract multipath fading than direct sequence systems, which, however, perform better in the presence of multiaccess interference, provided that diversity is used. >

Cordless Data Communications

Abstract: Integrated communication systems in the commercial environment are becoming increasingly important to the modern business. The consequent reduction in expensive, incompatible systems with their associated service contracts and skilled staff, and the benefits of increased economies of scale, promote the integrated solution. With the advent of products based on Integrated Services Digital Network (ISDN) technology this trend is likely to continue.

Private exchanger style wireless telephone system

Abstract: PURPOSE: To easily adapt this system to any requested change by forming a radio link chain through each adjacent transmitting/receiving unit with a central unit. CONSTITUTION: This radio telephone system designed as a private exchange 12 is provided with a central unit 26 connected through a radio link chain (radio bus) 27 with a subscriber's device 28 so that bi-directional communication can be attained. The subscriber's device 28 is constituted of plural subscriber's units designated as a cordless telephone, and the radio bus 27 is constituted of plural radio bus elements in the same structure. Each radio bus element is provided with transmitting/receiving units, and they are arranged so that the radio link chain 27 for the central unit 26 can be formed through each adjacent transmitting/receiving unit. Thus, when the layout of the rooms of a building is changed, the telephone system can rapidly and inexpensively be changed.