Reflex Type Patents (Class 455/342)
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Patent number: 5585780Abstract: In a traveling state calculating device, a sensing and sending unit senses the number of rotations of a wheel and sends by radio a signal indicative of the sensed number of rotations of the wheel to a calculating and displaying unit to thereby calculate and display the traveling speed and the covered distance. When the traveling state cannot be detected accurately due to interference of radio signals from other devices, the present traveling state calculating device senses the interference, and changes the frequency of the radio signal being used to another frequency to prevent continuation of the interference so as to calculate the traveling state accurately.Type: GrantFiled: June 20, 1994Date of Patent: December 17, 1996Assignee: Casio Computer Co., Ltd.Inventor: Toshiaki Sakashita
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Patent number: 5574976Abstract: A communication system has a PCC 101 which receives a data stream from a cordless base station 115. The cordless base station 115 transmits an indication in the data stream that it is going to begin a scan. While the cordless base station 115 is scanning, the PCC 101 performs a scan of its own. The PCC 101 also performs a scan when it determines that a message is a repeat and has been previously received.Type: GrantFiled: May 6, 1994Date of Patent: November 12, 1996Assignee: Motorola, Inc.Inventor: Michael J. Schellinger
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Patent number: 5568480Abstract: In radio transmission systems having a number of radio channels available for transmission, it is necessary to recognize a transmission channel as idle. One known way of doing this is to measure the field strength on the transmission channel and carry out a threshold decision. As soon as the field strength in a transmission channel is below a preset value, this transmission channel is recognized as idle. In measuring field strength, the field strength is averaged over the entire bandwidth of the transmission channel. As a result, a transmission channel that experiences interference from the signals on its adjacent channels may not be recognized as idle, although the adjacent-channel interference has little effect on the transmission quality. The new method makes it possible to recognize the signal present in a transmission channel by means of numerous narrowband field strength measurements.Type: GrantFiled: April 11, 1995Date of Patent: October 22, 1996Assignee: Grundig E.M.V. Elektro-Mechanische Versuchsanstalt Max GrundigInventor: Werner Muller
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Patent number: 5566358Abstract: A mobile radio communication apparatus includes a common channel detecting unit which judges whether or not a paging channel and an access channel which are assigned to one base station are common based on a predetermined parameter (CPA) which is transmitted from the base stations. If the CPA indicated a predetermined value indicating that the paging channel and the access channel are common channel, then a memory stores that information representing the base station which transmits the strongest level of all the received access channel at an input of a receiver of the mobile radio communication apparatus.Type: GrantFiled: March 6, 1995Date of Patent: October 15, 1996Assignee: Kabushiki Kaisha ToshibaInventors: Arata Obayashi, Takashi Sakagawa
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Patent number: 5561843Abstract: A mobile communications system accommodating both expanded spectrum (ES) mobiles and non-expanded spectrum (NES) mobiles incorporates a first set of (ES) channels and a second set of (NES) channels. A proportion of the channel requests from ES mobiles are allocated to a queue for NES channels. NES channels are allocated to these ES mobiles until no further NES resources are available. Further requests from ES mobiles in the NES channel queue are then met by allocating available ES channels. This provides an enhanced efficiency of utilisation of channel resources. Advantageously, a subset of NES channels is reserved for preferential use by NES mobiles to ensure fair allocation of channels between the two types of user, these channels being allocated to ES mobiles only if no other channels are currently available.Type: GrantFiled: March 21, 1995Date of Patent: October 1, 1996Assignee: Northern Telecom LimitedInventors: Ronald P. C. Tsang, Steven J. Willhoff
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Patent number: 5561847Abstract: A radio communication system represented by a micro cellular system and a channel allocation method suitable therefor. A receive signal level is measured in response to a call request issued from a mobile station. A search start channel is determined based on a measured level, and a search is sequentially made on a plurality of radio communication channels, starting with the thus determined search start channel, being a starting point. A radio communication channel specified by this search is subjected to evaluation of communication quality. The above search and communication quality evaluation are repeated while advancing the starting point to the subsequent radio communication channel until the evaluation result equals or exceeds a predetermined value. When the evaluation result equals or exceeds the predetermined value, radio communication is initiated between the mobile station and a base station by way of a specified radio communication channel.Type: GrantFiled: October 19, 1994Date of Patent: October 1, 1996Assignee: Mitsubishi Denki Kabushiki KaishaInventor: Nobuhisa Kataoka
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Patent number: 5555447Abstract: A communication system mitigates speech loss due to a delay (D) incurred during communication channel set-up and also accounts for the delay (D). The communication system time-compresses certain speech spoken by a user and buffers this time-compressed speech in a FIFO (827) at least until the communication channel set-up has been completed. Upon channel set-up, the communication system begins transmission of the stored time-compressed speech and transitions to transmission of normal spoken speech when the FIFO (827) storing the time-compressed speech is substantially empty.Type: GrantFiled: May 14, 1993Date of Patent: September 10, 1996Assignee: Motorola, Inc.Inventors: Michael D. Kotzin, Gary W. Grube
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Patent number: 5551064Abstract: A method and apparatus for establishing frequency assignments for a fixed radio communication unit of plural fixed radio communication units coupled via a controller. A controller functions to have the communication unit measure transmitted signal strengths, and to request the other fixed radio communication units to transmit at assigned frequencies. The system functions to identify and select one (or more) of the frequencies measured having the lowest signal strength and adjacent channel and/or co-channel interference characteristics beneath set threshold level(s). The system also operates to repeat the process for each fixed radio communication unit, until all are assigned frequencies.Type: GrantFiled: July 27, 1994Date of Patent: August 27, 1996Assignee: Motorola, Inc.Inventors: Dan W. Nobbe, Ronald L. Royer
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Patent number: 5548818Abstract: A method and system for radio communications between mobile units and base stations geographically distributed through a substantial geographic area described. The system automatically finds and engages broadcast frequency for each geographic region. The engagement is confirmed at both the mobile unit and network so that both can begin data transmission and reception between each other as well as keep track of the status of one another. The system also verifies the correct base station has been engaged as well as automatically terminates communications once the mobile unit passes out of coverage for that base station.Type: GrantFiled: August 25, 1992Date of Patent: August 20, 1996Assignee: Rockwell InternationalInventors: James G. Sawyer, Bruce S. Kloster, Ralph L. Kitson, Randall M. Kovatch, Daniel C. Roepke, M. Frank Wilson
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Patent number: 5542108Abstract: A communication unit that is registered in a trunked communication system can continue to receive a communication from a first communication unit after initiating a push-to-talk request while the first communication unit is transmitting voice data in the following manner. Having allocated a communication resource to a group of communication units and while processing a request to communicate for the first communication unit, a communication resource allocator receives a request to communicate from a second communication unit to produce a new request to communicate. The communication resource allocator stores the new request to communicate and transmits a response to the second communication unit such that the second communication unit can continue to receive the remainder of the communication from the first communication unit.Type: GrantFiled: December 5, 1994Date of Patent: July 30, 1996Assignee: Motorola, Inc.Inventor: Michael D. Sasuta
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Patent number: 5535429Abstract: A method of forcibly disconnecting a communications connection established between a mobile station and a mobile services switching network, depending on whether the communications connection initially allocated to the mobile station has deteriorated or that a call connection or a handover attempt has failed. With the intention of forcing the mobile station to relinquish the allocated channel, the network transmits to the mobile station a signal which activates a time monitoring process in the mobile station, which thereby sends an acknowledgement signal back to the network. When the network does not wish the mobile station to retain the allocated channel, a signal which would stop the time monitoring process is not sent to the mobile station, thereby resulting in the release of the communications channel. Also described is a mobile station which includes counter-circuits for effecting the time monitoring process.Type: GrantFiled: January 27, 1994Date of Patent: July 9, 1996Assignee: Telefonaktiebolaget LM EricssonInventors: Lars H. Bergenlid, Ulf C. Eklund
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Patent number: 5535426Abstract: Resource controllers (14) within a multisite communication system (20) selectively and automatically assume primary (45) and secondary (53) control modes of operation in order to ensure that adequate communication resources are assigned throughout the system at necessary sites in order to include talk group members that are dispersed throughout the system.Type: GrantFiled: December 13, 1993Date of Patent: July 9, 1996Assignee: Motorola, Inc.Inventors: Todd A. Leigh, Michael D. Sasuta, John K. Hefferan
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Patent number: 5524274Abstract: A transceiver having a transmitting unit and a receiving unit for performing substantially simultaneous communication with another transceiver in both directions by using a single frequency carrier. The transceiver includes a unit for generating a synchronizing signal for alternately switching between a transmission time period and a reception time period of the transceiver at a predetermined period, a signal processing unit for converting an input signal into a compressed signal by compressing a time axis of the input signal by a predetermined ratio, and affixing the synchronizing signal to the compressed signal, a unit for supplying the compressed signal with the synchronizing signal to the transmitting unit during the transmission time period, and a unit for reproducing an original signal from a signal transmitted from the other transceiver and received by the receiving unit during the reception time period, by expanding a time axis of the signal by a predetermined ratio.Type: GrantFiled: April 13, 1994Date of Patent: June 4, 1996Assignees: Hitachi Denshi Kabushiki Kaisha, Tohoku Electric Power Co., Inc., Fuji-Tekku Kabushiki KaishaInventors: Norio Takahashi, Nobuo Sekiguchi, Sakari Ohira, Fujio Sumi
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Patent number: 5517681Abstract: A random access method in a radio system having a plurality of radio stations and at least one base station serving the radio stations, in which the base station transmits an invoking message to the radio stations in a first time slot to grant the radio stations the right to send a random access message to the base station. One of the radio stations transmits a random access message containing a random identifier to the base station in a second time slot subsequent to the first time slot. The base station transmits a response message containing the random identifier to the radio station in a third time slot subsequent to the second time slot. In order to avoid allocating the same telecommunications resource for simultaneous use by more than one of the radio stations, the response message sent by the base station to the radio station in the third time slot contains the identifier of the second time slot.Type: GrantFiled: June 20, 1994Date of Patent: May 14, 1996Assignee: Nokia Telecommunications OyInventor: Reino Talarmo
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Patent number: 5515366Abstract: Direct communication between a primary portable unit initiating the communication and a secondary portable unit is established utilizing two handshaking operations. The first handshaking operation is performed in the base station channel to establish initial contact between the primary and secondary portable units. After initial contact is made, the second handshaking operation is performed to establish communication in an unoccupied channel. The base station channel and the unoccupied channel may be a TDMA/TDD channel or a TDMA/FDD channel.Type: GrantFiled: November 17, 1994Date of Patent: May 7, 1996Assignee: International Business Machines CorporationInventors: Trieu C. Chieu, Anand Narasimhan, Gary E. O'Neil, Li-Cheng R. Zai
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Patent number: 5507034Abstract: A method in a cellular communication system provides selection of a channel for use in a pending communications operation, the selection reducing the likelihood of co-channel interference. In each co-channel cell, frequencies from the cell's frequency group are ordered in a sequence. A different frequency in each cell is designated as having a highest priority. Successively lower priorities are then assigned, in each cell, to remaining frequencies in sequence. Then, in each cell, selection is made by identifying the available frequency having the highest priority. The method may be modified to provide for even distribution of hardware use by changing the priorities in each cell periodically. The method may also be modified for use in a fully synchronized time division multiple access (TDMA) system by performing the above steps with respect to channels instead of frequencies. The method may further be modified for use in a pseudo-synchronized TDMA system (i.e.Type: GrantFiled: September 1, 1993Date of Patent: April 9, 1996Assignee: Telefonaktiebolaget LM EricssonInventors: Roland Bodin, Harald Kallin, Lars M. Lindroth, Walter Ghisler
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Patent number: 5504939Abstract: A system for allocating communication channels within a cellular radio system in which each channel seizure request is assigned a call type based upon the capabilities of the mobile station, the nature of the call and the characteristics of the subscriber. A first algorithm is used to select a communication channel group for the call and a second algorithm is used to select an available communication channel from within the selected channel group.Type: GrantFiled: November 3, 1993Date of Patent: April 2, 1996Assignee: Telefonaktiebolaget L M EricssonInventors: Luc Mayrand, Hakan E. Olov, Hakan A. Claes
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Patent number: 5497148Abstract: A traffic information warning system for conveying traffic information from a traffic advisory site to a vehicle is disclosed. The traffic warning site comprises an emergency vehicle, a roadside hazard, or the like. The system comprises a transmitter adapted for placement at the advisory site and a receiver adapted for placement at the vehicle. The transmitter includes a first oscillator for transmitting a first unmodulated carrier signal at a first frequency and a second oscillator for transmitting a second unmodulated carrier signal at a second frequency. The first and second frequencies define the traffic information. The receiver includes a detector for detecting the first and second signals and an announcing device for announcing the traffic information.Type: GrantFiled: August 30, 1994Date of Patent: March 5, 1996Assignee: Cobra Electronics CorporationInventor: David C. Oliva
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Patent number: 5493695Abstract: This invention relates to a trunking radio system (FIG. 1) having a central station and at least one remote station for communication with the central station over a number of frequency-divided radio channels. The central station has a transmitter (10) for transmitting a number of signals to different remote units on different channels and a trunking controller (12) for allocating channels to different remote units. The trunking controller monitors the excess number of channels over the number of channels allocated to remote units. The central controller signals to a remote unit to allocate a channel to the remote unit when there is at least one excess channel. Signals received from the remote unit over the at least two channels are diversity combined (21). The remote unit has a receiver for receiving signalling from the central station and a diversity transmitter (34, 35, 39) responsive to the signalling for transmitting a signal over the at least two channels.Type: GrantFiled: June 18, 1993Date of Patent: February 20, 1996Inventors: Gary Aitkenhead, Nicholas W. Whinnett, Anthony P. Van Den Heuvel
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Patent number: 5491837Abstract: A method and system for the adaptive allocation of channels within a radio communication system, specifically a cellular network, is presented. The allocation method takes advantage of measurements made by the mobile radiotelephone and allocates channels based on the carrier to interference ratio. Using adaptive power control, consideration is given to maintaining an acceptable carrier to interference ratio while at the same time minimizing transmit power. Exemplary embodiments consider independent allocation of the uplink and downlink as well as independent determination of the uplink and downlink power levels. Other exemplary embodiments also give consideration to an efficient method for slot allocation in a TDMA communication system.Type: GrantFiled: March 7, 1994Date of Patent: February 13, 1996Assignee: Ericsson Inc.Inventor: Jacobus C. Haartsen
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Patent number: 5483673Abstract: Communication units are provided access to a communication system (100) in the following manner. A base station (202) receives, from a requesting communication unit, a request, via a shared inbound communication resource (209), for an available message path (207). When a dual-mode outbound communication resource is operating in a control mode (205), the message path (207), having a first inbound communication resource (204) and the dual-mode outbound communication resource operating in a partial control mode (206), is assigned to the requesting communication unit. Thus, the shared inbound communication resource is consistently available, providing access to the communication system.Type: GrantFiled: November 17, 1993Date of Patent: January 9, 1996Inventors: Bradley M. Hiben, Donald G. Newberg, Robert D. LoGalbo
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Patent number: 5475677Abstract: In a TDM/TDMA portable radio communications system, a portable handset is compatible for operation in both a frequency-division duplexing (FDD) mode for communication in the licensed portion of the Emerging Technologies frequency band, and in a time-division duplexing (TDD) mode for communication in the unlicensed portion of the Emerging Technologies frequency band. In the FDD mode, different frequencies are used to separate a downlink transmission to a portable from a port from an uplink transmission from a port to a portable. In the TDD mode, uplink and downlink transmissions are separated in different time-slots, but at the same frequency. The handset includes common transmit and receive circuitry that operates at fixed IF frequencies that are separated in frequency by the fixed FDD frequency difference between corresponding uplink and downlink signals.Type: GrantFiled: December 29, 1994Date of Patent: December 12, 1995Assignee: Bell Communications Research Inc.Inventors: Hamilton W. Arnold, Li F. Chang, Anthony R. Noerpel, Nelson R. Sollenberger, Robert A. Ziegler
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Patent number: 5471645Abstract: A method is provided of allocating channels in a trunked radio frequency communication system having a plurality of channels, each with a channel rate. The method includes the steps of transmitting channel characteristics on idle channels of the plurality of channels by a base site. Idle channels are then scanned for channel characteristics by a communication unit. The method also includes the step of seizing an idle channel, by the communication unit, based, at least in part, upon the channel characteristics.Type: GrantFiled: September 25, 1992Date of Patent: November 28, 1995Assignee: MotorolaInventor: Kenneth A. Felix
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Patent number: 5471646Abstract: A method is provided for a group of radios to establish a talk group in order for the radios to communicate with each other. The method allows for a group of radios (200) to select a talk group which users can communicate with one another, independent of how the radios in the trunked system (600) are grouped at the system-level.Type: GrantFiled: August 1, 1994Date of Patent: November 28, 1995Assignee: Motorola, Inc.Inventor: Charles P. Schultz
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Patent number: 5469472Abstract: In a digital communication system (100), a second message (309) may be substituted for a first message (301) by detecting a suitable transition point and beginning transmission of the second message at this transition point. In a frame-synchronous digital communication system, this transition point is a frame boundary within the first message.Type: GrantFiled: September 15, 1994Date of Patent: November 21, 1995Inventors: Robert W. House, Paul M. Bocci, James G. Edkins
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Patent number: 5465394Abstract: A device for seeking a connection between a terminal and a mobile radio system includes a synchronization unit for establishing in response to a control signal if the connection can be achieved and a time-delay unit for producing, after an initial period, the control signal after a first waiting period. The time-delay unit produces the control signal again after a second waiting period if it is established that the connection cannot be achieved after the first waiting period. The time-delay unit fixes the duration of the second waiting period so that it is greater than that of the first waiting period. If the device is implemented in a terminal having a battery whose capacity is represented by a capacity indicator, the time-delay unit fixes at least one of the waiting periods according to the capacity indicator.Type: GrantFiled: December 15, 1993Date of Patent: November 7, 1995Assignee: Alcatel RadiotelephoneInventors: Francis Pinault, Christophe Jouin
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Patent number: 5463617Abstract: A first communication unit (101) transmits, to a central controller (105), a request for a group call. The central controller allocates a first inbound (11), a second inbound (12), and an outbound (O.sub.1) wireless communication resource for use in the group call. At the central controller, primary voice signals from the first communication unit, received via the first inbound wireless communication resource, are summed (109) with interrupt voice signals from a second communication unit (102), received via the second inbound wireless communication resource, to produce summed voice signals. The summed voice signals and a busy signal (108) are transmitted via the outbound wireless communication resource, thereby allowing the second communication unit to interrupt the group call. Additionally, the central controller can allocate a third inbound communication resource (13) for use with priority interrupt voice signals which can also be summed with the primary and interrupt voice signals.Type: GrantFiled: September 30, 1994Date of Patent: October 31, 1995Inventors: Gary W. Grube, Brian K. Bunkenburg, Marc C. Naddell
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Patent number: 5455964Abstract: The frequency and power of transmissions in a mobile communication system, such as an air-to-ground telephony system, are stabilized without a priori knowledge of the system gain factors or frequency references. The ground station monitors the available channels and modifies a vacant channel broadcast message to provide information that the channel is available. In this way, the air terminals have knowledge of all available channels. The ground station transmits a pilot signal. Upon request by a user for a dial tone at the air terminal, the air terminal selects a vacant channel and scans for the pilot signal. The air terminal estimates a distance to the ground station and sets a power level of a seizing transmission based on the estimated distance. The air terminal also estimates a Doppler frequency shift of the selected channel due to the relative movement of the air terminal with respect to the ground station and sets a frequency of the seizing transmission based on the estimated Doppler frequency shift.Type: GrantFiled: March 26, 1993Date of Patent: October 3, 1995Assignee: Claircom Communications Group, Inc.Inventors: David A. Roos, John R. Clewer, Seok-Ho Kim, James E. Malcolm, Andrew W. Brandt, Allan A. D'Souza, Adrian J. Morris, Matthew M. Mohebbi
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Patent number: 5452471Abstract: A hierarchical communication network includes primary, secondary, and tertiary communication systems. The primary system uses orbiting satellites as communication nodes and forms a pattern of cells that may cover the entire earth and that move over the earth. A given spectrum is divided among the cells in accordance with a reuse plan. Any number of secondary, terrestrial-based systems have secondary region areas of coverage that are substantially smaller than the distance to the orbits of the satellites used by the primary system. Secondary systems monitor the primary system to determine which channels of the spectrum are available for use in their secondary regions. Any number of tertiary, terrestrial-based systems reside within a secondary region and have tertiary region areas of coverage that are substantially confined within buildings. Tertiary systems use channels concurrently used by the primary system in the same area where their tertiary regions are located.Type: GrantFiled: May 2, 1994Date of Patent: September 19, 1995Assignee: Motorola, Inc.Inventors: Raymond J. Leopold, Gregory B. Vatt, William F. Zancho
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Patent number: 5448752Abstract: In a mobile radio system wherein a common group call is concurrently transmitted by several primary stations, each primary station includes in the structure of the call the identities of other primary stations which are transmitting the same call. In a TDMA system these identities may be transmitted in a time slot of a dedicated frame F, such as a control slot C, a ramp slot R, or an associated control slot AC. When the quality of the call as received by a mobile secondary station deteriorates, handover to the best available primary station transmitting the same group call can therefore be effected directly by the secondary station without the need for a signaling exchange with the primary stations involved. The invention is also applicable to FDMA systems.Type: GrantFiled: April 8, 1993Date of Patent: September 5, 1995Assignee: U.S. Philips CorporationInventor: Peter J. Mabey
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Patent number: 5428601Abstract: A method of operating a communications system, particularly a FDM-TDD cordless telephony system, in which, in order to expedite handover, a portable secondary station builds up a record of the status and quality of the other FDM channels in the system by every 1 in n (where n is an integer greater than one) TDD frames monitoring another FDM channel. The value of n is adaptive in that, as the quality of its existing channel deteriorates, the value of n decreases, thereby updating its record more rapidly. At handover, the secondary station is able to choose immediately an acceptable alternative channel, thereby avoiding the time overhead of scanning all the other FDM channels.Type: GrantFiled: March 29, 1994Date of Patent: June 27, 1995Assignee: U.S. Philips CorporationInventor: Frank C. G. Owen
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Patent number: 5426666Abstract: There is disclosed a wireless communication apparatus for constituting a multi-station communication system, capable of preventing the interference to other communications and the deterioration in the quality of channel. The apparatus has a receiving unit and a transmitting unit, and prohibits the transmission by the transmitting unit according to the magnitude of the received output of the receiving unit.Type: GrantFiled: July 20, 1994Date of Patent: June 20, 1995Assignee: Canon Kabushiki KaishaInventor: Ichiro Kato
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Patent number: 5408682Abstract: With cordless telephones it is a known fact that each pair of radio stations has m radio channels out of n possible radio channels in common. During a test cycle the mobile unit examines only the common radio channels. Consequently, the test period required for testing only the common channels is shorter than the time necessary for testing all channels. If, by chance, all common channels are busy or if such a situation is the result of a malfunctioning, establishing a link between the base unit and the mobile unit is no longer possible. In the proposed embodiment of a cordless telephone, reliably establishing a link is guaranteed in that in a first test phase the common channels and in a second test phase all n radio channels are tested. A field of application of the invention is the cordless telephone.Type: GrantFiled: August 10, 1992Date of Patent: April 18, 1995Assignee: U.S. Philips CorporationInventors: Georg Ranner, Jurgen Hoflinger
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Patent number: 5408684Abstract: In the selection of a control channel of a mobile station in a radio zone to which some control channels are assigned as communication channels, the receiving levels of the control channels are sequentially measured and control channel candidates are selected. A check is made to see if a control signal can correctly be received in each of the selected control channel candidates, and if not, the number of signal reception failures in that channel is incremented by 1 in a memory used by the mobile rotation. A channel in which the number of signal reception failures has reached a predetermined value M (an integer equal to or greater than 1) is excluded from the group of control channel candidates, and the other selected control channel candidates are similarly checked to determine whether or not the reception of the control signal is possible in each of them.Type: GrantFiled: September 1, 1993Date of Patent: April 18, 1995Assignee: NTT Mobile Communications Network, Inc.Inventors: Kazufumi Yunoki, Katsumi Kobayashi, Kiyohito Nagata
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Patent number: 5404573Abstract: A control channel monitoring system is for a mobile communication system in which base stations independently control radio zones which are arranged in a cellular array. A mobile station accesses the base station using at least one control channel. Each of the base stations constantly transmits using the control channel in common according to a time division multiple access. A voice signal is transmitted between an arbitrary base station and the mobile station according to the time division multiple access via a speech channel. The control channel monitoring system includes a monitoring part for carrying out a monitoring operation in which a transmission quality of the radio zones is monitored by monitoring the control channel. A selection standard is obtained for the radio zone as the mobile station moves. A silence judging part determines whether the voice signal indicates a silent state based on a level of the voice signal.Type: GrantFiled: February 24, 1993Date of Patent: April 4, 1995Assignee: Fujitsu LimitedInventors: Toshihiro Yabe, Masaru Ohmori
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Patent number: 5396648Abstract: A method and apparatus whereby a communication unit (10) transmits a communication channel request and the nearest base site (12) makes the communication channel grant or allocation. A base site receives the channel request signal, measures the received signal strength (RSSI) level of the received signal, and if that level is above a threshold level, a communication channel is allocated to the requesting communication unit, thus establishing a communication link. If the channel request signal does not have an RSSI level above the threshold, the base site delays the grant of a communication channel for a period inversely proportional to the measured RSSI level to allow other base sites the opportunity to grant a communication channel to the requesting communication unit. If the base site determines that another base site has granted a communication channel to the requesting communication unit, the allocation process is stopped, and the base site continues scanning for channel request signals.Type: GrantFiled: June 8, 1993Date of Patent: March 7, 1995Assignee: Motorola, Inc.Inventors: Stelios J. Patsiokas, Thomas V. D'Amico, Charles D. Suter, Raul A. Pombo
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Patent number: 5392451Abstract: A satellite based paging communication system comprises at least one satellite capable of communicating the paging information to at least one terrestrial receiver some of which are capable of transmitting an acknowledge signal so that message reception may be verified and satellite traffic controlled.Type: GrantFiled: June 17, 1993Date of Patent: February 21, 1995Assignee: Motorola, Inc.Inventors: Robert J. Schwendeman, Willam J. Kuznicki
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Patent number: 5390360Abstract: In a radio frequency communication system, a primary unit interrogates a plurality of secondary units over a radio communication channel. The primary unit receives a command to initiate an interrogation cycle over the communication channel. The primary unit then selects a time delay from a set of time delays, and transmits an interrogation request to each secondary unit of at least a subset of the plurality of secondary units in series after the selected time delay if the channel is free at the end of the selected time delay. The primary unit then selects the longest time delay for the next interrogation cycle if a channel grant command is received, and selects a shorter time delay for the next interrogation cycle if no channel grant command is received.Type: GrantFiled: November 17, 1992Date of Patent: February 14, 1995Assignee: Motorola, Inc.Inventors: Shlomo Scop, Shmuel Katar
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Patent number: 5379448Abstract: A digital communication network has a plurality of remote terminals (RTs) which communicate with a plurality of base stations (BSs) by radio links operating at a single frequency. Each RT monitors the signal strengths of outbound messages and keeps an ordered table indicating which BSs produce the highest strength signals. At sign-on, an RT sends a message to the BS at the top of the list. The message includes the first predetermined number of entries at the top of the list. Each BS monitors the number of RTs it can hear and the number of users attached to each BS. The BS to which the sign-on message is sent then decides on the basis of signal strength, number of users attached, and BS coverage which BS should be attached to the particular RT and then notifies a communications controller. Such decision thus levels the workload. Each RT monitors errors and requests re-evaluation of attachment when the error rate for the BS to which it is attached exceeds a predetermined value.Type: GrantFiled: August 5, 1991Date of Patent: January 3, 1995Assignee: International Business MachinesInventors: Richard N. Ames, Thomas W. Kludt, Victor S. Moore
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Patent number: 5369783Abstract: In a trunked radio frequency communications system, a dynamic regrouping scheme includes an effective user interface, automatic support of multi-site systems, the capability to program individual radio transceivers with multiple new groups dynamically, a fast rate of reconfiguration, instantaneous switch over to prevent radios from residing in immature groups, and a satisfactory mode of operation should the site controller (or site controllers in non-fault tolerant systems) fail. Some of the dynamic regrouping features includes unlimited prestored plans and source and destination groups per plan, regrouping at the plan or destination group level, an advanced user interface, automatic support of multiple sites, fast regrouping at the rate of over 30 radios per second while reducing loading on the system control channel, and fast activation/deactivation. Each plan can be immediately activated or deactivated and users are effectively regrouped together.Type: GrantFiled: October 13, 1993Date of Patent: November 29, 1994Assignee: Ericsson GE Mobile Communications Inc.Inventors: Jeffrey S. Childress, David L. Hattey
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Patent number: 5363426Abstract: A method of determining when a communication device (11) is out-of-range of an incoming call from a central station (25), disallows communication between them for the out-of-range condition. In the central station (25), a page signal is transmitted (20) representing a call to the communication device (11). The central station (25) is capable of receiving (12) signals transmitted by the communication device (11). Recognizing (40) a lack of response by the communication device to the page signal from the central station, the central station withholds the transmission of a call set-up grant signal. Meanwhile, in the communication device, signals transmitted by the central station are received (50). The communication device transmits a page-response signal (555) representing the reception of the page signal.Type: GrantFiled: April 14, 1994Date of Patent: November 8, 1994Assignee: Motorola, Inc.Inventor: Scott O. Nyhart
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Patent number: 5345597Abstract: The call set-up technique of this invention is characterized by the use of channel information from both base station and subscriber terminal in determining the radio traffic channel upon which to set-up a new call. Communication between the base station and subscriber terminal is carried out on a signalling channel until the traffic channel is chosen. Calls are set-up so that they proceed on the radio channel which, of a set of channels under consideration by the subscriber terminal, contains the least amount of interference as measured at the subscriber terminal. The set of channels under consideration by the subscriber terminal is a subset of the entire set of channels allocated to the service. This subset is comprised of those channels having little interference, as measured by the base station. The call set-up technique thereby assures that calls proceed on channels containing little interference from the viewpoints of both base station and subscriber terminal.Type: GrantFiled: March 30, 1993Date of Patent: September 6, 1994Assignee: Northern Telecom LimitedInventors: Leo Strawczynski, Howard M. Sandler, Gregory L. Plett, David G. Steer
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Patent number: 5329530Abstract: A radio connection system capable of improving the number of successfully completed connections between base stations and mobile stations, without resorting to complicated control systems and, therefore, desirably obtaining dynamic channel assignment. A base station transmits a proposed available radio frequency to a mobile unit which has issued a connection request and then waits to receive an answer from the mobile unit in any slot timing at the proposed radio frequency. The mobile unit detects a time slot which it can use and returns an answer to the base station in that time slot.Type: GrantFiled: October 26, 1992Date of Patent: July 12, 1994Assignee: NEC CorporationInventor: Susumu Kojima
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Patent number: 5327578Abstract: A radio telephone communication system (200) having a base station (203) including at least one frequency agile time division duplex transceiver (207) for facilitating communication with at lest one radio telephone (100) on the at least one radio frequency channel. The radio telephone (100) scans a plurality of channels capable of being generated by the at least one frequency agile transceiver (207) to find an available channel and provide an indication representing a base station busy status when all the at least one frequency agile transceivers are in use. A base station busy status is indicated when one of a bidirectional time division duplex communication including a base station identification signal is being communicated by the at least one frequency agile transceiver or a unidirectional time division duplex communication including a base station identification signal is being communicated by the at least one frequency agile transceiver (207).Type: GrantFiled: August 25, 1992Date of Patent: July 5, 1994Assignee: Motorola, Inc.Inventors: Robert L. Breeden, Gary S. Lobel, Thomas V. D'Amico
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Patent number: 5327573Abstract: An intersystem communication path (20, 67) can be established on an as needed basis. Already established paths are fully utilized before new paths are established. Already established paths can be automatically disconnected when no longer needed, or when existing calls can be merged on to fewer lines. Dial up lines can be mixed with dedicated lines. If desired, excess capacity can be guaranteed to accommodate high traffic conditions and/or other conditions that precipitate a likely need for communication services between systems.Type: GrantFiled: March 12, 1993Date of Patent: July 5, 1994Assignee: Motorola, Inc.Inventors: Vitaly Lenchik, Robert W. Furtaw, David S. Robins
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Patent number: 5323447Abstract: A cordless telephone arranged for operation in a frequency hopping system automatically modifies a frequency hopping sequence in the presence of interference detected on its in-use communication channels. Substitute alternative communication channels are identified and then substituted for those communication channels experiencing the interference without disruption of communications between a handset unit in the cordless telephone and its associated base unit.Type: GrantFiled: November 1, 1991Date of Patent: June 21, 1994Assignee: AT&T Bell LaboratoriesInventors: Mark E. Gillis, Kenneth W. Leland, William J. Nealon, Hon Yu
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Patent number: 5293419Abstract: A simultaneous voice-call system for a cordless telephone where communication between a base unit and a plurality of portable units is established through the use of a radio communication channel. The base unit includes a transmitter/receiver which establishes a communication channel between base unit and plurality of portable units. The transmitter/receiver has a control channel and a plurality of talk channels. A portable-unit-identifying number memory stores portable-unit-identifying numbers preassigned to the plurality of portable units. A first simultaneous call controller responsive to a simultaneous call command from a user to establish a talk-channel between the plurality of portable units by transmitting through the control channel portable-unit-identifying numbers stored in the portable-unit-identifying number memory, a vacant-talk-channel number, and a simultaneous call code to the plurality of portable units.Type: GrantFiled: April 29, 1992Date of Patent: March 8, 1994Assignees: Pioneer Electronic Corp., Pioneer Communications Corp.Inventor: Masahiro Hirano
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Patent number: 5274837Abstract: A digitally trunked radio repeater system provides substantial improvements in timeliness of channel acquisition and channel drop, and in reliability of critical control signalling. The system uses a much higher digital signalling rate than is typically found in prior art systems, and uses a control channel to convey digital channel request and assignment messages between the central site and mobile transceivers. The mobile radio transceivers transmit channel requests on the control channel (if no response is received, the mobile retries during a retry time window which increases in duration in dependence on the number of retries). The mobile transceiver switches to a working channel in response to an assignment message received on the control channel. Subaudible digital signals transmitted on the control channel and on active working channels allow late entry, shifting to higher priority calls, and other advanced functions.Type: GrantFiled: March 30, 1992Date of Patent: December 28, 1993Assignee: Ericsson GE Mobile Communications Inc.Inventors: Jeffrey S. Childress, Marc A. Dissosway, Gerald M. Cooper, Houston H. Hughes, III
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Patent number: 5267244Abstract: In a wireless communication system between a base unit and a remote unit, the base unit transmits periodically a sync signal in a first selected time period in a selected frequency channel. The remote unit scans the frequency channels to detect the sync signal. The remote unit transmits a response signal in the selected frequency channel. The response signal is transmitted in a second selected time period different from the first selected time period. In addition, the remote unit transmits a first control signal encoded by a first code in the selected frequency channel in a third selected time period, different from the first and second selected time periods, containing a set of functional capabilities of the remote unit. The base unit receives and decodes the first control signal to derive the set of functional capabilities of the remote unit and compares it to its own set of functional capabilities to determine a common set of functional capabilities.Type: GrantFiled: November 8, 1991Date of Patent: November 30, 1993Assignee: Teknekron Communications Systems, Inc.Inventors: David G. Messerschmitt, Christopher Flores, Hulhung Lu
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Patent number: 5267261Abstract: In a code division multiple access (CDMA) spread spectrum cellular communication system in which a mobile station user communicates with another system user via at least one base station, wherein each base station transmits a common pilot signal of a different code phase with respect to other base stations in said system, a method for directing communications between said mobile station user and said base stations. The mobile station monitors the signal strength of pilots and reports the measured signal strength to a system controller via the base station through which it is communicating. Command messages from the system controller to a new base station and the mobiles station establishes communication through the new base station in addition to the communication through the current base station.Type: GrantFiled: March 5, 1992Date of Patent: November 30, 1993Assignee: Qualcomm IncorporatedInventors: Robert D. Blakeney, II, Gadi Karmi, Edward G. Tiedemann, Jr., Lindsay A. Weaver, Jr.