Showing papers on "Communications system published in 1999"

Antennas and Propagation for Wireless Communication Systems

Abstract: From the Publisher: This title introduces the basic concepts and specific applications of antennas and propagation to wireless systems, covering terrestrial and satellite radio systems in both mobile and fixed contexts. Includes: Illustrations of the significance and effect of the wireless propagation channelOverview of the fundamental electromagnetic principles underlying propagation and antennasBasic concepts of antennas and their application to specific wireless systemsPropagation measurement, modeling, and predication for fixed links for macrocells, microcells, picocells, and megacellsNarrowband and wideband channel modeling and the effect of the channel on communication system performanceMehtods that overcome and transform channel impairments to enhance performance using diversity, adaptive antennas, and equalizersExamples of real-world practical system problems of communications design and operationExtensive worked examplesEnd-chapter questionsTopical and relevant information for and about the wireless communications industry.

Method for providing communication services over a computer network system

Abstract: A system, method and article of manufacture are provided for implementing communication services patterns. A fixed format stream-based communication system is provided and service is delivered via a globally addressable interface. Access is afforded to a legacy system. Service is delivered via a locally addressable interface. A null value is communicated and data is transmitted from a server to a client via pages. A naming service and a client are interfaced with the naming service allowing access to a plurality of different sets of services from a plurality of globally addressable interfaces. A stream-based communication system is provided and data is efficiently retrieved.

System and method for vehicle diagnostics and health monitoring

Abstract: A system and method for vehicle diagnostic and health monitoring includes a client computer device within the vehicle, coupled to the vehicle's monitoring systems, for data management, remote session management and user interaction, a communication system, coupled to the client computer device, for providing remote communication of data including data derived from internal monitoring systems of the vehicle, and a remote service center including a vehicle data store, a server computer, a diagnostic engine, and a communicator for communicating the results of analysis of vehicle information to the client computer device via the communication system.

Satellite positioning system augmentation with wireless communication signals

Abstract: A method and apparatus for processing position information from satellite positioning system satellites and from cellular based communication signals In one example of a method according to the invention, a SPS receiver receives SPS signals from at least one SPS satellite This SPS receiver is coupled to and typically integrated with a communication system which receives and transmits messages in a cell based communication system In this method, a message is transmitted in the cell based communication signals between a communication system and a first cell based transceiver A time measurement which represents a time of travel of a message in the cell based communication signals between the cell based transceiver and the communication system is determined Another time measurement which represents a time of travel of the SPS signals is also determined A position of the SPS receiver is determined from a combination of at least the time measurement which represents the time of travel of a message in the cell based communication signals and from a time measurement which represents a time of travel of the SPS signals The cell based communication signals are capable of communicating data messages in a two-way direction in one embodiment between the cell based transceiver and the communication system

System and process for limiting distribution of information on a communication network based on geographic location

Abstract: A communication system includes a plurality of recipient processors (14, 15, 16) located at geographically remote locations with respect to each other and connected for communication with an information provider processor (12), over the communications network. The provider (12) and recipient processors (14, 15, 16) may comprise respective computers coupled for communication on the Internet or WWW. The provider processor is capable of providing information from any suitable source, by communicating such information over a communications network. However, access to the information by the recipient processors is controlled, based on the geographic location or region of the recipient processors. Each recipient processor is operably associated with a positioning system for providing geographic location information corresponding to the location or region in which the positioning system is located, such as a global positioning system GPS (20, 21, 22). The geographic position information is used to determine whether or not the processor requesting the information is within a restricted or non-restricted region.

Medical monitoring and alert system for use with therapeutic devices

Abstract: An integrated medical monitoring and alert system for monitoring a medical therapy delivered to a patient and patient physiological parameters is disclosed. The medical monitoring system preferably includes a central monitoring system and one or more of a therapeutic device, a patient monitor, and an integrated alert system. The components are linked together through a bi-directional communications system which can comprise a wireless communications link to provide for mobile patients and communications to remote caregivers.

Reducing cross-interference in a combined gps receiver and communication system

Abstract: A method and apparatus is disclosed for reducing cross-interference in a combined satellite positioning system receiver and communication transceiver device. A control signal is transmitted from the communication transceiver to the satellite positioning system receiver when the communication transceiver transmits data at a high power level over a communication link. The control signal causes satellite positioning system signals from satellites to be blocked from the receiving circuits of the satellite positioning system receiver, or to be disregarded by the processing circuits of the satellite positioning system receiver.

Passive optical fast frequency-hop CDMA communications system

Abstract: This paper proposes an all-fiber fast optical frequency-hop code division multiple access (FFH-CDMA) for high-bandwidth communications. The system does not require an optical frequency synthesizer allowing high communication bit rates. Encoding and decoding are passively achieved by Bragg gratings, Multiple Bragg gratings replace a frequency synthesizer, achieving a hopping rate in tens of GHz. A main lobe sine apodization can be used in writing the gratings to enhance the system capacity and the spectrum efficiency. All network users can use the same tunable encoder/decoder design. The simultaneous utilization of the time and frequency domains offers notable flexibility in code selection. Simulations show that the encoder efficiently performs the FFH spread spectrum signal generation and that the receiver easily extracts the desired signal from a received signal for several multiple access interference scenarios. We measure the system performance in terms of bit error rate, as well as auto-to cross-correlation contrast. A transmission rate of 500 Mb/s per user is supported in a system with up to 30 simultaneous users at 10/sup -9/ bit error rate. We compare FFH-CDMA to several direct sequence-CDMA systems in terms of bit error rate versus the number of simultaneous users. We show that an optical FFH-CDMA system requires new design criteria for code families, as optical device technology differs significantly from that of radio frequency communications.

Ground link with on-board security surveillance system for aircraft and other commercial vehicles

Abstract: A comprehensive surveillance/communication system supports communication of monitored data and/or commands or operational data between the ground or base station and the transport, between the transport and ground or terminal support vehicles and/or equipment, between the transport and various monitoring stations or systems, between transports, between the ground station and the support vehicles, between the monitoring station and support vehicles and between the monitoring stations or systems and the support vehicles. This permits the ground station to monitor and/or determine the identity, location, and heading of any vehicle in its range for tracking and collision avoidance, as well as monitoring sensor information, alarm conditions, emergency conditions, servicing requests, maintenance information, navigational information, requests for information such as flight plans, weather information, route maps, message traffic such as e-mail and the like. Similar information may be transmitted and received between any combination of transports, monitoring stations, personnel, mobile units and support vehicles. Operational commands may also be transmitted utilizing the system of the invention.

Fixed format stream in a communication services patterns environment

Abstract: A system, method, and article of manufacture provide a fixed format stream-based communication system. A sending fixed format contract on interface code is defined for a sending system. A receiving fixed format contract on interface code is also defined for a receiving system. A message to be sent from the sending system to the receiving system is translated based on the sending fixed format contract. The message is then sent from the sending system and subsequently received by the receiving system. The message received by the receiving system is then translated based on the receiving fixed format contract.

Wireless area network communications module for utility meters

Abstract: A communications module that permits remote meter reading of a utility meter via a wireless modem that communicates using data packet networks along a communications system, such as ARDIS. The communications module is a microprocessor-based transmitter/receiver which receives data collection requests from a system server, initiates data collection from a utility meter, and reports the data back to a host computer system residing, for example, at a central office. Preferably, session-based communication using the meter protocol is implemented between the communications module and the meter, and packet switching is used between the communications server and the communications module through the network.

Satellite communication system

Abstract: In a radio frequency communications system, a data carrier activation method is implemented such that the carrier is switched off when no data is available for transmission. If repeated signalling information is required to be transmitted, only a predetermined number of repeats is transmitted before the carrier is switched off. The data input for transmission are compared with an idle sequence with different bit alignments to detect the presence of idle signalling, and the carrier is switched off if a match is found. When more user data is received, the carrier is switched on and frames (SM) are transmitted in synchronization with the timing of frames (SM) transmitted before the carrier deactivation. After carrier reactivation, a constant power preamble (P) may be transmitted to assist in level control in the transmitter (27; 40).

Carrying speech-band signals over a power line communications system

Abstract: Speech-band signals such as voice telephony and facsimile are transmitted over a power line communications system. The method comprises: receiving speech-band signals at the communications station from speech-band communications equipment; digitising the speech-band signals; encoding the digitised signals into data packets; and transmitting the data packets to/from a station over a part of the line which is external to the premises, using a packet data communications protocol. Equipment can selectively route the speech-band signals via the power line or the PSTN.

Land vehicle communications system and process for providing information and coordinating vehicle activities

Abstract: A communication system architecture (SA) for a vehicle which may be integrated into the vehicle's multiplexed electronic component communication system, and a process for communicating with the vehicle to provide information for and about the vehicle's operational status and coordinating the vehicle's activities. The communication system will include a multi-functional antenna system for the vehicle that will have the capability to receive AM/FM radio and television signals, and transmit and receive citizens band (CB) radio signals, satellite and microwave and cellular phone communications. The antenna may be installed as original equipment or as a back-fit part in the after-market. In either case the multi-functional antenna will be integrated with the vehicle's multiplexed electronic component communication system. The process for communicating with the vehicle will involve a communication service for which the vehicle's driver will enroll for and service will continue so long as maintenance fees are paid. The service will be capable of providing various levels of information transfer and coordination. The levels may include vehicle information such as (1) the need for servicing and location of the nearest service center with the necessary parts in stock, (2) routing, and (3) load brokering and coordination. The modular design of the system architecture (SA) will allow it to be employed with the vehicle platform that does not possess a full multiplexed electronic component communications system. The resulting vehicle, using an after-market application package, will be able to participate in some of the services.

Multiple-room signal distribution system

Abstract: A multiple-room communication system is adapted to provide digital television programming (e.g. DBS) to a plurality of rooms in a single family dwelling and may be further adapted to provide digital television programming to a plurality of dwelling units in a multiple dwelling unit such as an apartment. A central unit includes a plurality of integrated receiver decoder modules that receive e.g. satellite signals from a satellite antenna and filter and supply the signals to a distribution system that is coupled to a plurality of display devices that are located in various rooms throughout the single family home. A plurality of hand-held remote controllers, each being associated with one of the integrated receiver decoder modules, are used to communicate with and control the associated integrated receiver decoder module to cause it to supply a desired signal to a desired display device. Each of the remote controllers are adapted to ensure exclusive communication with the associated integrated receiver decoder module and to prevent interference with the operation of the other integrated receiver decoder modules. A single power supply is used to power the co-located integrated receiver decoder modules, and a single modem is used to report billing information to the satellite provider.

Real-time fieldbus communications using Profibus networks

Abstract: This paper provides a comprehensive study on how to use Profibus fieldbus networks to support real-time industrial communications, that is, on how to ensure the transmission of real-time messages within a maximum bound time. Profibus is base on a simplified timed token (TT) protocol, which is a well-proved solution for real-time communication systems. However, Profibus differs with respect to the TT protocol, thus preventing the application of the usual TT protocol real-time analysis. In fact, real-time solutions for networks based on the TT protocol rely on the possibility of allocating specific bandwidth for the real-time traffic. This means that a minimum amount of time is always available, at each token visit, to transmit real-time messages, transversely, with the Profibus protocol, in the worst case, only one real-time message is processed per token visit. The authors propose two approaches to guarantee the real-time behavior of the Profibus protocol: (1) an unconstrained low-priority traffic profile; and (2) a constrained low-priority traffic profile. The proposed analysis shows that the first profile is a suitable approach for more responsive systems (tighter deadlines), while the second allows for increased nonreal-time traffic throughput.

System and method for providing directions using a communication network

Abstract: A communication system includes mobile units, a network switching center, and service centers to provide a variety of enhanced services to the mobile units. The service centers and/or the network switching centers determine directions from an origination location to a destination location. The directions, which may comprise multiple segments separated by separator signals, are communicated to the mobile unit using a communication network. The mobile unit may present each segment of the directions to a user. In one embodiment, the mobile unit generates a service message specifying an origination location and a destination location. The directions are determined in response to the service message.

Wireless spread spectrum ground link-based aircraft data communication system for engine event reporting

Abstract: The system and method of the present invention provides a record of the flight performance of an aircraft and the performance of the engine. A plurality of sensors sense engine conditions and generate engine data. A ground data link unit is positioned within the aircraft and receives the engine data. At initial take-off, a spread spectrum transmitter downloads the engine data to an airport based spread spectrum receiver that receives the spread spectrum communication signal from the aircraft upon initial take-off and demodulates the spread spectrum communication signal to obtain the engine data after initial take-off. The ground data link unit can also include a data store that is operative to accumulate and store flight performance data during flight of the aircraft. The spread spectrum transceiver is coupled to the data store and can download the flight performance data after the aircraft has landed at its destination airport.

A multi-path signal propagation model for the powerline channel in the high frequency range

Abstract: For the use of the mains networks as high speed data path for Internet, voice and data services carrier frequencies within the range from 500 kHz up to 20 MHz must be considered. The development of suitable communication systems and the planning of power line communication networks requires measurement-based models of the transfer characteristics of the mains network in the abovementioned frequency range. ' The heterogeneous structure of the mains network with numerous branches and impedance mismatching causes numerous reflections. Besides multi-path propagation with frequency-selective fading, typical power cables exhibit signal attenuation increasing with lengtli and frequency. The complex transfer function of n power line link can be described by a parametric model in the considered frequency range. Measurements of amplitude and phase response of a sample network with well-known geometry approve the validity of the model. Comparisons with measurements conducted at ,,live6' mains networks prove the validity of the model also for real network topologies.

Contemporary Communication Systems Using MATLAB

Abstract: Signals and linear systems random processes analog communications analog-to-digital conversion baseband digital transmission channel equalization carrier modulation systems channel capacity and coding spread spectrum communications.

System, device and method for expediting control flow in a communication system

Abstract: A system, device, and method for expediting control flow in a communication system involves establishing a separate control channel for high priority control messages between two network nodes and exchanging high priority control messages over the control channel. The control channel may be a physical or virtual channel. Within a particular network node, a separate high priority queue is used for transferring high priority control messages between a control plane and a forwarding plane.

Communications system and method, fleet management system and method, and method of impeding theft of fuel

Abstract: A communications system for communications between a vessel and a fluid management system, the communications system comprising a proximity detector supported by the vessel and configured to detect presence of a fuel nozzle in a fluid entry port of the vessel; and an RFID supported by the vessel, coupled to the proximity detector, and configured to communicate with a RFID interrogator to identify the vessel to the RFID interrogator, and to communicate whether the nozzle is in the fluid entry port A method of impeding theft of fuel, the method comprising establishing a first communication link between a vehicle and a fuel delivery system; establishing a second communication link between the vehicle and the fuel delivery system; communicating using the second communication link, from the vehicle to the fuel management system, that the first communication link is established; delivering fuel from the fuel delivery system to the vehicle in response to the communicating; and suspending the delivering in response to a break in the first communication link

Method and apparatus for efficient GPS assistance in a communication system

Abstract: A method and apparatus for efficiently transmitting location assistance information to a mobile communication device over a control channel with a minimal impact on the capacity of the control channel. A position location server provides a difference between satellite locations which have been computed using Almanac data and then Ephemeris data. Sending only the difference between the locations and satellite clock corrections computed using the two different data types, the total amount of information to be transmitted to a mobile communication device is significantly reduced. Furthermore, by providing rate of change information, the method and apparatus allows the location assistance information to remain valid for a relatively long time after it is has been received by the mobile communication device.

Communications involving disparate protocol, network/bus and device subsystems

Abstract: A communications apparatus for enabling communications among networks, buses, devices and other subsystems having different communication requirements is provided. The communications apparatus offers an open architecture for interoperability among diverse subsystems. The communications apparatus is particularly applicable in a vehicle. In one embodiment, a portal apparatus located remote from the vehicle facilitates communications with the communications apparatus, particularly where the vehicle is part of a vehicle fleet. The communications apparatus includes a common module that has at least one protocol by which disparate subsystems can communicate with each other. One or more managers can be defined as being part of the common module. The disparate subsystem managers provide the necessary interfacing to enable the disparate subsystems to communicate between and among each other using the common module. Each such manager has dedicated functionalities to facilitate communications. Managers associated with the common module may include managers for use in configuration and diagnostic tasks, encryption/decryption, compression/de-compression, controlling data flow, security regulation, and selecting an acceptable link for outside communications. The common module also includes a base manager for registering disparate subsystem managers including associating a name with each of them.

Gps location for mobile phones using the internet

Abstract: A position locating system and method are provided for determining a geographic location of a portable remote unit. The locating system includes a communications system having at least one base station and a system controller. The base station bi-directionally couples the remote unit to the system controller through wireless links. The locating system also includes a server coupled to the system controller by a communication infrastructure external to the communications system. The server includes a data store which contains satellite positioning information. In response to a message from the remote unit, the server provides satellite information to the system controller over the communication infrastructure such that the provided satellite information is passed to the remote unit by the base station. The provided satellite information includes information to aid in acquiring a predetermined number of satellites within a satellite positioning system. The acquired satellites provide coded signals for determining the geographic location of the remote unit. In one embodiment, the data communication system is a cellular telephone network and the communication infrastructure is the Internet. The Internet is coupled to the cellular telephone network through a public switched telephone network (PSTN).

Communications system handoff operation combining turbo coding and soft handoff techniques

Abstract: Communication systems, including, for example, cell-based mobile communication systems, multiple satellite communication systems, or multibeam satellite systems, require reliable handoff methods between cell-to-cell, beam-to-beam, or satellite-to-satellite respectively. Recent measurement of a CDMA cellular system indicates that the system is in handoff about 30 % to 50 % of an average call period. Therefore, system reliability during handoff is one of the major system performance parameters and eventually becomes a factor in the overall system capacity. The present invention advantageously relates to novel and improved techniques for handoff in cellular communications, multibeam and multisatellite systems. The present invention combines the soft handoff mechanism with a code diversity combining technique (i.e., combining signals from multiple sources), a packet combining technique (i.e., combining multiple signals), and an iterative decoding algorithm (e.g., Turbo Coding (502)).

Multicarrier personal access communication system

Abstract: A highly modular PACS-based system that combines the advantages of Optical Frequency Division Multiplexing (OFDM) and Personal Access Communication System (PACS) with Time Division Multiple Access (TDMA) technology. The system is arranged to support high-speed (higher than the 32 kbps of PACS) wireless access services to fixed and mobile users. For example, nominal user data rates of 32-to-356 kbps are attainable, and ever the higher speed of 768 kbps is possible for short ranges.

Communication system with fast control traffic

Abstract: A method and system for conducting rapid control traffic in a time division multiple access (TDMA) communication system comprises a base station communicating with a plurality of user stations in assigned time slots of a time frame. For bearer traffic, time slots are assigned to particular user stations for an extended duration. In unassigned time slots, the base station transmits a general polling message indicating availability of the time slot. A user station desiring to hand off communication from one base station to another uses multiple available time slots at the target base station for exchanging control traffic messages with the target base station. The next available time slot is indicated by a slot pointer in the header of each general polling message to facilitate rapid exchange of control traffic messages. During handover, the user station may establish a new link with the target base station before relinquishing the existing communication link with the old base station.

Virtual workplace intercommunication tool

Abstract: A system and associated method for enabling a user to determine the status of other users and to identify communications procedures for contacting the other users based on the status of the other users. The system includes a plurality of communications devices each associated with a user. Each of the communications devices is operable for the associated user to self assign a user status and communications procedures for contacting the associated user as a function of the user status. Each of the communications devices associated with a user is operable for displaying the user status of the other users. A hybrid fiber coax (HFC) communications network is operable with the communications device for providing continuous communications connectivity of a plurality of users with one another through an Internet. Each of the communications devices associated with a user is operable for displaying the communications procedures associated with the other users for contacting the other users. The communication device associated with a user is operable with the HFC communications network and the communication device associated with another user for enabling the user to select a communication method from the communication methods associated with the another user and then establish a communication connection with the another user based on the selected communications procedure.

Vehicle locating system utilizing global positioning

Abstract: A vehicle locating system (200) includes a beacon (108) carried by a vehicle, a tracking control station (106) for generating a beacon activation signal (110) which enables the beacon (108) to broadcast a vehicle identification signal (112), and one or more mobile communication devices (116, 118) which include a first receiver (516) utilized to receive a location signal (122) identifying a geographic location of a mobile communication device, and a transceiver (406) utilized to provide communication between said mobile communication device and a communication system controller. The one or more mobile communication devices (116, 118) further include a second receiver (502) utilized to receive the vehicle identification signal (112) broadcast by the beacon (108), and a vehicle tracking controller (520), responsive to the vehicle identification signal (112) which is received, for controlling a transmission of the vehicle identification signal (112) and the location signal (122).