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Showing papers on "Communications system published in 1992"


Patent
15 Dec 1992
TL;DR: In this article, a communication system (20) is provided with multiple purpose personal communication devices (50 and 150), each communication device includes a touch-sensitive visual display (60 and 160) to communicate text and graphic information to and from the user and for operating the communication device.
Abstract: A communication system (20) is provided with multiple purpose personal communication devices (50 and 150). Each communication device (50 and 150) includes a touch-sensitive visual display (60 and 160) to communicate text and graphic information to and from the user and for operating the communication device (50 and 150). Voice activation (78) and voice control capabilities (76) are included within communication devices (50 and 150) to perform the same functions as the touch-sensitive visual display (60 and 160). The communication device includes a built-in modem (82), audio input and output (52 and 53), telephone jacks (86), and wireless communication (90). A plurality of application modules (100) are used with personal communication devices (50 and 150) to perform a wide variety of communication functions such as information retrievable, on-line data base services, electronic and voice mail. Communication devices (50 and 150) and application modules (100) cooperate to allow integrating multiple functions such as real time communication, information storage and processing, specialized information services, and remote control of other equipment into an intuitively user friendly apparatus. The system (20) includes both desktop (150) and hand-held communication devices (50) with the same full range of communication capabilities provided in each type of communication device (50 and 150).

1,025 citations


Book
31 Mar 1992
TL;DR: An overview of the fundamental principles behind modeling and simulation of communication systems is presented, which include Monte Carlo simulation, discrete time representation, signals, and random-number generation.
Abstract: Simulation plays an important role in the design, analysis, and implementation of communication systems During the design of complex communication systems it is often infeasible to conduct performance analysis and design tradeoff studies using closed-form mathematical formula techniques Quite frequently, simulation is the only tool available for addressing important issues in the design, analysis, and implementation of communication systems Simulation can be used to verify the functionality of communication systems, evaluate the performance of proposed systems, and generate specifications to guide their design Since the early 1980s a variety of modeling and simulation techniques and tools have been developed and used to support the design and implementation of a broad range of communication systems and products ranging from multi-million-dollar communication satellites to handsets for the next generation of personal communication systems This article presents an overview of the fundamental principles behind modeling and simulation of communication systems Keywords: communication systems; discrete time representation; signals; systems; modeling of functional blocks; simulation of functional blocks; Monte Carlo simulation; random-number generation; performance estimation

853 citations


Patent
22 Sep 1992
TL;DR: In this paper, a central data processor, a control unit for each gaming machine within the system, and a user interface which includes a keypad, a card reader and a display.
Abstract: An information and communication system permits communication between gaming machines and a central control system and between a player or operator and a central control system. The system includes a central data processor, a control unit for each gaming machine within the system which is in communication with the central data processor and a user interface which includes a keypad, a card reader and a display. A user interface is secured to each gaming machine and operatively connected to the control unit. The keypad can be used by a player or operator to transmit information to the central data processor. The control unit can be used to identify special players and transmits messages, including promotional messages, for display. The control unit includes memory which contains personality data for the gaming machine and can be used to transmit the personality data from the user interface to its memory. The control unit can accept personality data from a card inserted into the card reader and can be enabled by a personal identification number entered on the keypad. The system provides multiple features including automated maintenance, game accounting, security, player tracking, event tracking, employee/player interaction from the game to the central data processor, cashless operation of gaming machines, reserving gaming machines and other functions.

751 citations


Patent
01 Oct 1992
TL;DR: In this article, an apparatus and a method for routing data in a radio data communication system having one or more host computers, one/more intermediate base stations, and one/or more RF terminals is presented.
Abstract: An apparatus and a method for routing data in a radio data communication system having one or more host computers, one or more intermediate base stations, and one or more RF terminals organizes the intermediate base stations into an optimal spanning-tree network to control the routing of data to and from the RF terminals and the host computer efficiently and dynamically. Communication between the host computer and the RF terminals is achieved by using the network of intermediate base stations to transmit the data.

705 citations


Patent
10 Aug 1992
TL;DR: In this article, a multilaterating two-way message delivery system for mobile resource management provides efficient twoway radio data communication for multitudes of portable transponders (22) using a single frequency in half-duplex communication.
Abstract: A multilaterating two-way message delivery system for mobile resource management provides efficient two-way radio data communication for multitudes of portable transponders (22) using a single frequency in half-duplex communication. The system includes at least one transponder device (22) which transmits and receives data using a radio frequency communication link, and an array of at least three bases (12a-f) which communicate with the transponder device (22) using the radio frequency communication link. The radio frequency communication link employed by each base station (12a-f) and the transponder device (22) is designed to provide multilateration information and to deliver message data simultaneously. Further, a control arrangement (10) is coupled to the array of base stations to coordinate the communication between the base stations (12a-f) and the transponder devices (22). Time division multiplex and spread spectrum technology is employed by the system for communication efficiency and minimizing the effect of multipath interference.

618 citations


Patent
05 May 1992
TL;DR: In this article, a tracking system employing global positioning system (GPS) satellites provides extremely accurate position, velocity, and time information for vehicles or any other animate or inanimate object within any mobile radio communication system or information system, including those operating in high rise urban areas.
Abstract: A tracking system employing global positioning system (GPS) satellites provides extremely accurate position, velocity, and time information for vehicles or any other animate or inanimate object within any mobile radio communication system or information system, including those operating in high rise urban areas. The tracking system includes a sensor mounted on each object, a communication link, a workstation, and a GPS reference receiver. The sensor operates autonomously following initialization by an external network management facility to sequence through the visible GPS satellites, making pseudo range and delta range or time difference and frequency difference measurements. No navigation functions are performed by the sensor, thereby permitting significant reductions in the cost thereof. The raw satellite measurements, with relevant timing and status information, are provided to the communication link to be relayed periodically back to the workstation. Differential corrections may also be provided at the workstation to increase the accuracy of the object location determination. In normal operation, three satellite measurements are required to compute the location of the object, but for a short time period a minimum of two satellite measurements are acceptable with time, altitude, and map aiding information being provided by the workstation.

478 citations


Patent
21 Feb 1992
TL;DR: In this paper, a method and apparatus for increasing the capacity of wireless broadcast communications system from a central studio to a plurality of users in a service area is disclosed, where the high-rate signal is split into several low-rate signals such that each can be accommodated within the allocated bandwidth.
Abstract: A method and apparatus for increasing the capacity of wireless broadcast communications system from a central studio to a plurality of users in a service area is disclosed. Given a source signal whose high information rate exceeds the practical information carrying capacity of the available broadcast channel bandwidth, the invention increases the effective capacity of the broadcast system to effectively communicate such a source signal. The high-rate signal is split into several low-rate signals such that each can be accommodated within the allocated bandwidth. These low-rate signals are transmitted from spatially separated transmitters, all radiating into the service area in the same frequency channel. Each receiver uses a plurality of antennas to receive these multiple cochannel signals that arrive from different directions-of-arrival. The receiver exploits the directions-of-arrival differences of these cochannel signals to separate them into the individually transmitted signals. The separated signals are then demodulated to extract the information signals which are then combined to obtain the original high-rate source signal. Thus, the broadcast information capacity can be increased several-fold.

382 citations


Patent
Durrell W. Hillis1
23 Jul 1992
TL;DR: In this article, a communication system service billing arrangement that adapts to system loading in real-time is described, where one or more individual subscribers units (ISU) (15,20) are provided with realtime information on the current cost of the communication service, and the system determines the locations of the ISUs and the current loading there between (31) and calculates a calling rate (32) based at least on current loading.
Abstract: A communication system service billing arrangement is described that adapts to system loading in realtime. As system loading varies, one or more individual subscribers units(ISU) (15,20) of a communication system (8) are provided with realtime information on the current cost of the communication service. The system determines the locations of the ISUs (34) and the current loading there between (31) and calculates a calling rate (32) based at least on the current loading. This calling rate (42) is sent (43) to at least one of the ISUs (15) whose operator can choose to connect or not connect the call between the ISUs based on the current realtime variable rate.

285 citations


Patent
13 Jan 1992
TL;DR: In this paper, a local area network including at least one hub unit, one associated station unit and a wireless communication link between each hub unit and its associated station units is described.
Abstract: A local area network including at least one hub unit, at least one associated station unit and a wireless communication link between each hub unit and its associated station units. The communication link includes a wireless down-link channel for transferring information from each hub unit to its associated station units and a wireless up-link channel for transferring information from each station unit to its associated hub unit. Communication is conducted in accordance with a combination time division multiplexing and contention based protocol. A synchronized common slotted time frame between each hub unit and its associated station units is imposed by the hub unit.

272 citations


Patent
30 Jun 1992
TL;DR: In this paper, a CDMA cellular radio-telephonesystem (Fig. 2) comprises a packet-switched communications network (202, 207, 201) that interconnects cells (base stations; 202) with each other and with the public telephone network (100).
Abstract: A wireless-access communications system, such as a CDMA cellular radio-telephonesystem (FIG. 2), comprises a packet-switched communications network (202, 207, 201) that interconnects cells (base stations; 202) with each other and with the public telephone network (100). Traffic of individual calls is packetized, and packet-bearing frames (300 in FIG. 7) of a plurality of calls are then statistically multiplexed and frame-relayed through the network to yield the high capacity, efficiency, and speed of traffic transport and handoff required for a CDMA cellular system. At each call processing unit (264 in FIG. 5), individual calls are handled by individual service circuits (602 & 612) which perform speech-processing functions such as coding and decoding, tone insertion, and echo cancellation, and packet-to-circuit-switched-PCM traffic conversion. Processors (602) adapt call processing unit timing to compensate for asynchrony between cells and call processing units and variations in call path transmission delays. Cell-to-cell communications, fixed call path addressing, and packetized control message transfers ensure that the same service circuit handles a call through even multiple soft handoffs (FIGS. 27 - 29) and efficiently communicates simultaneously with all cells involved in the handoff without involvement of system control entities and negative effect on system call-handling capacity. Both coded (packet-switched) and uncoded (circuit-switched) radio-telephone traffic are accommodated side-by-side. Wherever possible, existing and proven technology and component units are used to achieve low cost and high reliability.

262 citations


Book
01 Jan 1992
TL;DR: This book discusses components of a Digital Communication System, Signals, Systems, Modulation, and Noise, and Design Examples and System Tradeoffs, and some Commonly Used Modulation Schemes.
Abstract: (NOTE: Most chapters begin with an Introduction and conclude with Summary, References, and Problems.) 1. Introduction to Digital Data Transmission. Components of a Digital Communication System. Communications Channel Modeling. Communication Link Power Calculations. Driving Forces in Communications. Computer Use in Communication System Analysis and Design. Preview of the Book. 2. Signals, Systems, Modulation, and Noise: Overview. Review of Signal and Linear System Theory. Basic Analog Modulation Techniques. Complex Envelope Representation of Bandpass Signals and Systems. Signal Distortion and Filtering. Practical Filter Types and Characteristics. Sampling Theory. Random Processes. Computer Generation of Random Variables. 3. Basic Digital Communication Systems. The Binary Digital Communications Problem. Signaling through Bandlimited Channels. Equalization in Digital Data Transmission. A Digital Communication System Simulation Example. Noise Effects in Pulse Code Modulation. 4. Signal-Space Methods in Digital Data Transmission. Optimum Receiver Principals in Terms of Vector Spaces. Performance Analysis of Coherent Digital Signaling Schemes. Signaling Schemes Not Requiring Coherent References at the Receiver. Comparison of Digital Modulation Systems. Comparison of M-ary Digital Modulation Schemes on Power and Bandwidth-Equivalent Bases. Some Commonly Used Modulation Schemes. Design Examples and System Tradeoffs. Multi-h Continuous Phase Modulation. Orthogonal Frequency Division Multiplexing. 5. Channel Degradations in Digital Communications. Synchronization in Communication Systems. The Effects of Slow Signal Fading in Communicative Systems. Diagnostic Tools for Communication System Design. 6. Fundamentals of Information Theory and Block Coding. Basic Concepts of Information Theory. Fundamentals of Block Coding. Coding Performance in Slow Fading Channels. 7. Fundamentals of Convolutional Coding. Basic Concepts. The Viterbi Algorithm. Good Convolutional Codes and Their Performance. Other Topics. 8. Fundamentals of Repeat Request Systems. General Considerations. Three ARQ Strategies. Codes for Error Detection. 9. Spread-Spectrum Systems. Two Communication Problems. Types of Spread-Spectrum Systems. Complex-Envelope Representation of Spread Spectrum. Generation and Properties of Pseudorandom Sequences. Synchronization of Spread-Spectrum Systems. Performance of Spread-Spectrum Systems in Jamming Environments. Performance in Multiple User Environments. Multiuser Detection. Examples of Spread-Spectrum Systems. 10. Introduction to Cellular Radio Communications. Frequency Reuse. Channel Models. Mitigation Techniques for the Multipath Fading Channel. System Design and Performance Prediction. Advanced Mobile Phone Service. Global System for Mobile Communications. Code Division Multiple Access. Recommended Further Reading. 11. Satellite Communications. Allocation of a Satellite Transmission Resource. Link Power Budget Analysis. Examples of Link Power Budget Calculations. Low- and Medium-Earth Orbit Voice Messaging Satellite Systems. Appendix A. Probability and Random Variables, Probability Theory. Random Variables, Probability Density Functions, and Averages. Characteristic Function and Probability Generating Function. Transformations of Random Variables. Central Limit Theorem. Appendix B. Characterization of Internally Generated Noise. Appendix C. Attenuation of Radio-Wave Propagation by Atmospheric Gases and Rain. Appendix D. Generation of Coherent References. Description of Phase Noise and Its Properties. Phase-Lock Loop Models and Characteristics of Operation. Frequency Synthesis. Appendix E. Gaussian Probability Function. Appendix F. Mathematical Tables. The Sinc Function. Trigonometric Identities. Indefinite Integrals. Definite Integrals. Series Expansions. Fourier Transform Theorems. Fourier Transform Pairs. Index.

Patent
23 Sep 1992
TL;DR: In this article, a wireless telephone system (10) capable of servicing a roaming wireless telephone user (30) includes a satellite (22) communications system consisting of at least one orbiting satellite, a plurality of terrestrial communications links (e.g. 101) via a single relay through a single satellite or a succession of single relay satellites (22), wherein the relay station may be in motion relative to the end user transceiver apparatus (501) and the terrestrial communications link (101).
Abstract: A wireless telephone system (10) capable of servicing a roaming wireless telephone user (30) includes a satellite (22) communications system consisting of at least one orbiting satellite (22); at least one terrestrial-based gateway (12, 14, 16, 18) having access to a database (20) of users, destination codes (telephone numbers); at least one network coordinating gateway (28) within at least one satellite service area (24); a single network control center (25); and a plurality of terrestrial communications links (e.g. 101). The system (10) operates by effecting communication between a terrestrial wireless telephone end user transceiver apparatus (e.g. 501) and a terrestrial communications link (e.g. 101) via a single relay through a single satellite (22) or a succession of single relay satellites (22) wherein the relay station may be in motion relative to the end user transceiver apparatus (501) and the terrestrial communications link (101). The ground-based gateway (28) effects the ultimate decision on linking in cooperation with the network database to effect hand-off from a first orbiting satellite (22) to a second orbiting satellite (22). The single satellite (22) or preferably a constellation of satellites (22) orbiting near the earth need only translate signals from the gateways (12, 14, 16, 18) to the users (30) and from the users (30) to the gateways (12, 14, 16, 18), without satellite-based control.

Journal ArticleDOI
TL;DR: Several of the major design issues behind portable multimedia terminals, including spectrally efficient picocellular networking, low-power digital design, video data compression, and integrated wireless RF transceivers, are discussed.
Abstract: A personal communications system (PCS) that centers on integration of services to provide access to data and communications using a specialized, wireless multimedia terminal is described. The possible applications and support systems for such a terminal are outlined. Several of the major design issues behind portable multimedia terminals, including spectrally efficient picocellular networking, low-power digital design, video data compression, and integrated wireless RF transceivers, are discussed. It is argued that optimizing performance in each of these areas is crucial in meeting the performance requirements of the overall system and providing a small, lightweight terminal for personal communications. >

Patent
02 Dec 1992
TL;DR: In this article, a communication system co-located at a cellular MTSO is used to capture detailed call information by examining the switch's Automated Message Accounting data in real-time.
Abstract: Method and apparatus for collecting call detail (104a), monitoring customer account balance for excessive charges (400), and controlling the capabilities of cellular subscriber stations cellular telephone switch in substantially real time is disclosed. A communication system co-located at a cellular MTSO is used to capture detailed call information (104a) by examining the switch's Automated Message Accounting data (400) in real-time. Call records are parsed, rated for toll and air charges and stored in a database (400). A software system monitors the billing activity on the customer account for excessive charges. When excessive charges take place, a connection between the communication system and the cellular telephone switch control port (500) allows commands to be issued directly from the communication system to the cellular telephone switch providing operational control of selected cellular telephones.

Patent
Gary J. Grimes1, Lawrence John Haas1
01 Oct 1992
TL;DR: In this paper, the location of any potential system user is provided and call forwarding for that user is accomplished without the prior art problems associated with activation and deactivation, where the communications device is a pager which communicates with the wired or wireless telephone sets connected to the line side of the PBX to provide the system user relative to these telephone sets.
Abstract: A communications signal-transmitting device carried by a communications system user indicates the location of that user relative to other wired or wireless communications devices connected to a communications system. This location indication is utilized by the communications system to forward incoming voice and/or data communications for that user to the other communications device so that the user can receive such communications. As a result, the location of any potential system user is provided and call forwarding for that user is accomplished without the prior art problems associated with activation and deactivation. In the disclosed embodiments which pertain to the forwarding of voice communications in a PBX environment, the communications device is a pager which communicates with the wired or wireless telephone sets connected to the line side of the PBX to provide the PBX with the location of the system user relative to these telephone sets.

Patent
06 Oct 1992
TL;DR: In this article, a method and system for conducting multiple access simultaneous telephone communications in full duplex either over the power lines of a building or using RF transmission is presented, which employs a combination of multiple access techniques selected from among the following: time division, code division, and frequency division.
Abstract: A method and system for conducting multiple access simultaneous telephone communications in full duplex either over the power lines of a building or using RF transmission. It employs a combination of multiple access techniques selected from among the following: time division, code division, and frequency division. The following features result: a) security coding to prevent unauthorized access and eavesdropping, b) multiple simultaneous conversations through identical and closely coupled transmission media, c) non-interference to other communications systems and users, and d) processing gain for operating in noisy environments.

Patent
01 Jun 1992
TL;DR: In this paper, a dynamic capacity allocation spread spectrum CDMA communications system for overlaying, at least in part, geographically and in frequency a radio-relay system is presented, where the first power level is compared to a predetermined threshold.
Abstract: A dynamic capacity allocation spread spectrum CDMA communications system for overlaying, at least in part, geographically and in frequency a radio-relay system A first receiver, located near the relay receiver of the radio-relay system, measures a first power level within the relay bandwidth of the radio-relay system A second receiver, located near the relay receiver, measures a second power level outside the relay bandwidth of the radio-relay system The first power level is compared to a predetermined threshold A ratio signal is generated from the first power level and the second power level When the first power level exceeds the predetermined threshold, the ratio signal is used to regulate the power level and dynamically allocate the capacity transmitted from each spread-spectrum-base station

Patent
08 Jul 1992
TL;DR: In this paper, a communication system for determining the optimum direction for transmitting and receiving a signal in a radio comprises a receiver for receiving a carrier signal being a time divided signal having an in-struction signal, a transmitter for transmitting a time di-vided signal, and a directional antenna coupled to said receiver and transmitter, and steering device (28) for changing the phase of the carrier signal in accordance with the instruction signal.
Abstract: A communication system (100) for determining the optimum direction (206) for transmitting and receiv-ing a signal in a radio comprises a receiver for receiving a carrier signal being a time divided signal having an in-struction signal, a transmitter for transmitting a time di-vided signal, a directional antenna (10) coupled to said receiver and transmitter, and a steering device (28) for changing the phase of the carrier signal in accordance with the instruction signal.

Journal ArticleDOI
TL;DR: It is shown that the hyperbolic frequency hop codes possess nearly ideal characteristics for use in both types of system, specifically, in multiple-access communications the codes achieve minimum error probability, while in radar and sonar systems the codes have at most two hits in their auto- and cross-ambiguity function.
Abstract: The problem of constructing frequency hop codes for use in multiuser communication systems such as multiple-access spread-spectrum communications and multiuser radar and sonar systems is addressed. Previous frequency hopping techniques are reviewed. The construction of a new family of frequency hopping codes called hyperbolic frequency hop codes is given. The concepts of multiple-access spread-spectrum communication systems and multiuser radar and sonar systems are reviewed, and it is shown that the hyperbolic frequency hop codes possess nearly ideal characteristics for use in both types of system. Specifically, in multiple-access communications the codes achieve minimum error probability, while in radar and sonar systems the codes have at most two hits in their auto- and cross-ambiguity function. Examples of address assignment for multiple-access communications systems and radar and sonar auto- and cross-ambiguity functions are also given. >

Patent
12 Jun 1992
TL;DR: In this article, the authors propose a method for revising selected data in a distributed data communication system, e.g., a data program or document intended for a number of a plurality of destination devices (AEI, AEII, LSE2, L SE3) individually selected by an administrator, in which each destination device includes at least one memory unit for individual storage of data.
Abstract: The invention relates to an arrangement and to a method for revising selected data in a distributed data communication system, e.g. such data as a data program or document intended for a number of a plurality of destination devices (AEI, AEII, LSE2, LSE3) in the data communication system individually selected by an administrator, in which each destination device includes at least one memory unit (ME, LSM2, LSM3) for individual storage of data. The revision involves, for instance, installing and/or changing the selected data, a) a list of the selected destination devices is established; b) a procedure for the revision of the data on the selected destination devices is established and the procedures (L2; C2) are stored as a revision recipe; c) there is created a data package which at least contains the data to be revised and its revision recipe; d) the data package is distributed internally in the data communication system to the selected destination devices; e) the selected destination devices interpret the information in the data package with the aid of a special interpretation program installed in each destination device and initiating procedures on the basis thereof.

Patent
03 Jun 1992
TL;DR: In this paper, a hybrid of controlled access and random access schemes using frequency hopping spread spectrum communication techniques is implemented in an indoor digital data radio communication system between mobile stations and a computer system.
Abstract: A hybrid of controlled access and random access schemes using frequency hopping spread spectrum communication techniques is implemented in an indoor digital data radio communication system between mobile stations and a computer system. A hop in the frequency hopping spread spectrum communication system is subdivided into two intervals so that different media-access protocols can be used in each interval. The protocol uses a centralized control scheme in one interval and a decentralized scheme in the other, and the intervals may be varied depending on the load of the system.

Journal ArticleDOI
TL;DR: The erasure of unreliable symbols improves the performance of most types of error-control coding if a good method is used to decide which symbols should be erased and error probabilities are reduced by several orders of magnitude.
Abstract: The erasure of unreliable symbols improves the performance of most types of error-control coding if a good method is used to decide which symbols should be erased. Bayesian decision theory is employed to obtain such a method for use in frequency-hop communications with Reed-Solomon coding and errors-and-erasures decoding. The performance of frequency-hop communications with Bayesian erasure insertion is analyzed for channels with both partial-band and wideband Gaussian noise. The Bayesian technique is compared with Viterbi's ratio-threshold test, and these are compared to receivers that do not erase and use errors-only decoding. Comparisons are also made with receivers that erase all the symbols that are affected by the partial-band interference. When interference is strong, large coding gains result from the Bayesian method, and error probabilities are reduced by several orders of magnitude. >

Patent
27 Apr 1992
TL;DR: In this paper, a frequency agile sharing technology (FAST) system for controlling frequent usage in a communications system is described, which combines theoretical radio frequency interference analysis with measurements of actual frequency usage and allows for efficient and coordinated dynamic frequency allocation planning and management.
Abstract: A frequency agile sharing technology (FAST) system for controlling frequent usage in a communications system is disclosed. Specifically, a frequency agile sharing technology system of controlling frequency usage and eliminating interference for use with a Personal Communications Service (PCS) System is described. The frequency control system allows PCS systems to coexist in the same frequency band as Private Operational Fixed Microwave Service (POFS) systems without mutual interference. This system also controls frequency usage within a PCS system to eliminate interference from within the PCS system. This interference elimination system combines theoretical radio frequency interference analysis with measurements of actual frequency usage and allows for efficient and coordinated dynamic frequency allocation planning and management. To control frequency assignment and eliminate interference, the system employs several mechanisms including an intersystem interference analysis, an intrasystem interference analysis, a channel use verification (CUV) procedure, and a measured data analysis (MDA). These mechanisms are performed by a centralized controller, channel utilization controller (CUC), comprised of interference analysis/frequency planning computer programs with supporting data bases and data communication links. The system and method described allows for PCS frequency use around existing microwave users and can be readily adapted for use in any area and most efficiently make use of the available communications spectrum in that area. The system protects existing microwave users from interference while providing high quality PCS to subscribers utilizing small, low power and lightweight handsets in the same frequency band.

Patent
26 Jun 1992
TL;DR: In this paper, a store data communications system, multiple data sources having disparate communications standards are connected with respective device interfaces of a multiple device communications controller unit, where multiple protocol controllers are coupled with the device interfaces and convert the data from each to a common protocol for transmission via a single telephone line.
Abstract: In a store data communications system, multiple data sources having disparate communications standards are connected with respective device interfaces of a multiple device communications controller unit. Multiple protocol controllers are coupled with the respective device interfaces and convert the data from each to a common protocol for transmission via a single telephone line. The interface units preferably can be customized to operate with various data sources, a fiber optic coupler, or a modem, or another controller unit for convenient expansion. The device interfaces preferably have snap-in assembly with the controller unit so that device interfaces customized to different standards can be inserted or replaced at any interface receptacle, the multiple protocol controllers preferably being capable of corresponding re-programming by downloading from a remote station preferably via one of the device interfaces.

Patent
05 Oct 1992
TL;DR: In this paper, a source communication unit initiates a request for a dispatch call, and the request is routed to a controller which assigns a controlled device to support the request, but only one representation of a message produced by the source unit is transmitted from the assigned controlled device.
Abstract: Processing of dispatch calls in a multi-site communication system begins when a source communication unit initiates a request for a dispatch call. The request is routed to a controller which assigns a controlled device to support the request. In addition, the controller identifies the destination communication units, which site each of the destination units are in, and what controlled devices are needed to support the dispatch call. Having identified the controlled devices, the controller assigns all of the controlled devices needed the same temporary network address. With all the controlled devices having the same temporary network address, the controlled device assigned to support the request can transmit the messages generated by the source communication unit to other controlled devices using the temporary network address. Thus only one representation of a message produced by the source communication unit is transmitted from the assigned controlled device.

Patent
30 Sep 1992
TL;DR: In this article, a method and apparatus for reliably delivering messages (200) from a central terminal (102) to a communication receiver (130) in a communication system (100), such as an electronic mail system, is presented.
Abstract: A method and apparatus for reliably delivering messages (200) from a central terminal (102) to a communication receiver (130) in a communication system (100), such as an electronic mail system. The central terminal (102) sequentially transmits messages (200) to the communication receiver (130) and the communication receiver (130) receives transmitted messages (200) over a first communication medium (122). The communication receiver (130) reconciles messages that it failed to receive over the first communication medium (122) with the central terminal (102) over a second communication medium (152). The reconciliation between the communication receiver (130) and the central terminal (102) utilizes message sequence identifiers (208) transmitted with the messages (200) that identify the transmission sequence of the sequentially transmitted messages (200).

Patent
26 Mar 1992
TL;DR: In this paper, a communication resource is subdivided as a function of time into a plurality of time slots, which may then be further subdivided on a non-periodic basis into a number of sub-slots.
Abstract: A communication resource is subdivided as a function of time into a plurality of time slots (210), which may then be further subdivided on a non-periodic basis into a number of sub-slots (220). In a slot or sub-slot, communication units (101) may utilize the communication resource according to a specific set of access methods defined for that slot or sub-slot. In one embodiment the time slots are subdivided on a non-periodic basis into at least two random access sub-slots, during which communication units may either request one or more reserved time slots, or send unreserved data packets (240). In response to requests for reserved time slots from a requesting communication unit, one or more reserved time slots are provided for the use of the requesting communication unit.

Patent
27 Mar 1992
TL;DR: In this article, a communication unit (100) for operation in a communication system (600) includes a plurality of communication units (100), and a control resource (300), including a transmitter (118) for transmitting a signal to the control resources (300) requesting programming information using a bootstrap mode of operation.
Abstract: A communication unit (100) for operation in a communication system (600). The communication system (600) includes a plurality of communication units (100) and a control resource (300). The communication unit (100) includes a transmitter (118) for transmitting a signal to the control resource (300) requesting programming information using a bootstrap mode of operation. The communication unit (100) also includes a receiver (106) for receiving programming information sent by the control resource (300). The communication unit (100) further includes a controller (112) coupled to the transmitter (118) and the receiver (106) for programming the communication unit (100) using the received programming information.

Patent
29 May 1992
TL;DR: In this paper, a utility meter reading and communications system gathers data from utility meters and sends that data to a utility company's central data collection point (host computer) via phone lines.
Abstract: A utility meter reading and communications system gathers data from utility meters and sends that data to a utility company's central data collection point (host computer) via phone lines. The system places a call on the user's telephone line at a specified time and date and transmits data using dual-tone multifrequency (DTMF) format. The system ensures that users still may use the telephone line by sensing off-hook conditions initiated by a resident's telephone and immediately dropping the line to reestablish dial tone for the residential customer. The system uses a variety of error-detection procedures and communications protocols to ensure a high degree of reliability in communicating data to and from the central office and the utility meter system. The system also uses communications protocols and handshaking to ensure accurate data communication and allow immediate interruptions of communications should the customer attempt to use the telephone line.

Patent
10 Aug 1992
TL;DR: In this article, the ratio of peak power level to average power level (500) in a power amplifier used in a QAM communication system transmitter (100) can be reduced by preselecting magnitudes and phase angles of complex-valued pilot symbols (103-106) used in multi-channel (111-116), N-level QAM.
Abstract: The ratio of peak power level to average power level (500) in a power amplifier used in a QAM communication system transmitter (100) can be reduced by preselecting magnitudes and phase angles of complex-valued pilot symbols (103-106) used in multi-channel (111-116), N-level QAM.