Patents Represented by Attorney Kevin A. Buford
  • Patent number: 5577043
    Abstract: A method and apparatus for controlling communications on a multipoint communication link includes a multipoint link (29) coupling plural slave stations (11-13) and a master (10) having a communications controller (35) controlling signaling broadcast to slave stations (11-13) via an encoder (36). Broadcast signals (201-205) each include a time slot marker or identifier associated with a slave station. Master (10) monitors via detector (32) for response signals (211-213) within a window period, and when detected waits until an end of transmission and generates the next broadcast signal with an incremented marker. Master (10) also functions to cycle through broadcast signals to all slave stations (11-13) at an adaptive rate, e.g., more frequently for active as compared with idle or inactive slave stations.
    Type: Grant
    Filed: September 21, 1994
    Date of Patent: November 19, 1996
    Assignee: Motorola, Inc.
    Inventors: Eileen J. Guo, Jeffrey W. Klingberg
  • Patent number: 5574728
    Abstract: In a data communication system (100) including infrastructure (101) arranged to communicate with a plurality of terminals (103) over a channel (109), a method of adaptable registration includes determining a registration status (401), and executing a registration contention procedure adaptable to the registration status (403). A corresponding method of facilitating adaptable registration includes determining a registration contention information (501), the registration contention information corresponding to a contention procedure implemented by the plurality of terminals, and sending a message corresponding to said system registration information (519).
    Type: Grant
    Filed: June 27, 1995
    Date of Patent: November 12, 1996
    Assignee: Motorola, Inc.
    Inventors: Farzan Mamaghani, Thomas W. Lockhart, William H. Kilner
  • Patent number: 5572193
    Abstract: A method and apparatus for authentication between a subscriber unit and a communication unit is provided. The authentication process includes: maintaining an historic non-arbitrary value in the subscriber unit, generating an authentication message in the subscriber unit as a function of at least part of the historic non-arbitrary value, and transmitting the authentication message to the communication unit. In addition, the authentication process includes: receiving an authentication message at a communication unit, maintaining an historic non-arbitrary value in the communication unit, and determining, in the communication unit, through the use of the received authentication message and the maintained historic non-arbitrary value, whether a received service request is authentic.
    Type: Grant
    Filed: August 22, 1994
    Date of Patent: November 5, 1996
    Assignee: Motorola, Inc.
    Inventors: Mary B. Flanders, Louis D. Finkelstein, Larry C. Puhl
  • Patent number: 5559866
    Abstract: A method of providing communication services in a cellular communication system which consists of a plurality of service coverage areas having a plurality of shared frequency microcells. Each microcell has an omnidirectional, remote antenna interconnected with a base site. The method consists of receiving a request, at the base site, to provide communication access to a communication unit. A supervisory audio tone is simulcast through each omnidirectional, remote antenna of the plurality of shared frequency microcells. A signal quality factor of a looped-back supervisory audio tone received from the communication unit at each omnidirectional, remote antenna is then measured. A communication link between the communication unit and base site is then established through a selected antenna of said plurality of omnidirectional, remote antennas. The antenna is selected based upon the signal quality factor of the looped-back supervisory audio tone.
    Type: Grant
    Filed: January 20, 1995
    Date of Patent: September 24, 1996
    Assignee: Motorola, Inc.
    Inventor: Frank O'Neill
  • Patent number: 5555266
    Abstract: A packet transmission system (100) with reduced transmission delays includes a communications controller (110) and a plurality of remote requesting units (112) requesting packet transmission services. Each remote unit (112) sequentially stores transmitted access requests (302) in a memory queue (500) and awaits a resource grant (306) from the communications controller (110). Upon receipt of a granted resource the remote unit (112) will apply the granted resource to the oldest request (502) stored in the queue (500) in order to transmit data (310) to the communications controller (110). A separate and distinct aspect of the transmission system (100) resides within the communications controller (110).
    Type: Grant
    Filed: October 4, 1993
    Date of Patent: September 10, 1996
    Assignee: Motorola, Inc.
    Inventors: Dale R. Buchholz, Karen E. Robbins, R. Lee Hamilton, Jr., William K. Doss
  • Patent number: 5554988
    Abstract: An apparatus is provided for generating a multiple-level amplitude modulated data signal. The circuit provides accurate data signal level control while minimizing transient errors. A controlling level, relative to an analog reference level is provided. Multiple bit reference levels are generated from the controlling level and analog reference level. A method is provided for selecting one of the reference levels.
    Type: Grant
    Filed: August 23, 1994
    Date of Patent: September 10, 1996
    Assignee: Motorola, Inc.
    Inventors: Michael H. Retzer, Alan D. Muehlfeld
  • Patent number: 5553101
    Abstract: A data demodulation logic unit (200) and method used therein, adaptable to multiple data protocols, including an arithmetic logic unit (205) that is architecturally optimized to demodulate multiple data protocols under the control of a hardware based state machine (209) that operates in a selectable mode that corresponds to one of multiple data protocols.
    Type: Grant
    Filed: October 16, 1995
    Date of Patent: September 3, 1996
    Assignee: Motorola
    Inventors: Ricardo Lim, Marek Dutkiewicz
  • Patent number: 5551064
    Abstract: 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: Grant
    Filed: July 27, 1994
    Date of Patent: August 27, 1996
    Assignee: Motorola, Inc.
    Inventors: Dan W. Nobbe, Ronald L. Royer
  • Patent number: 5548598
    Abstract: An improved method of forward error correction in a data communications system that includes receiving a data frame that includes a filler symbol, detecting an error in the data frame, replacing the filler symbol with a predetermined symbol, and determining when the error has been corrected. Detecting the error includes performing a first parity check, preferably a CRC computation that is repeated a second time, after replacing the filler symbol, to determine when the error has been corrected. When replacing the filler symbol(s) has corrected the error, an automatic retry request may be foregone thus conserving channel capacity.
    Type: Grant
    Filed: March 28, 1994
    Date of Patent: August 20, 1996
    Assignee: Motorola
    Inventor: Pierre Dupont
  • Patent number: 5536905
    Abstract: A self secured housing includes a frame with openings, a first cover disposed on a first side of the frame and mechanically coupled to a plurality of semi flexible first fingers that are arranged for disposal in the openings with some of the semi flexible first fingers having a concave interlocking detail, and a second cover disposed on a second side of the frame and mechanically coupled to a plurality of semi flexible second fingers that are similarly arranged for disposal in the openings. The second fingers are further arranged to urge a corresponding one of the first fingers toward a side of the opening and engage the convex interlocking detail with the concave interlocking detail, thereby securing the frame between the first cover and the second cover.
    Type: Grant
    Filed: April 4, 1994
    Date of Patent: July 16, 1996
    Assignee: Motorola, Inc.
    Inventors: Brian Redman, Poh C. Low, Yiu-Kwong Chan
  • Patent number: 5535207
    Abstract: A method of dynamically allocating active time slots for a terminal (103) that is operating in a packet data communications system (100) which includes a fixed network (101) and user terminals (103), the system using a channel organized into time slots for scheduling data communications between the network and the user terminals, the method including first communicating information, further including a terminal ID and a packet key, representative of an active time slot pattern for the user terminal to the network; and second entering, at the user terminal, an active mode during each active time slot of the active time slot pattern.
    Type: Grant
    Filed: May 20, 1994
    Date of Patent: July 9, 1996
    Assignee: Motorola, Inc.
    Inventor: Pierre Dupont
  • Patent number: 5532643
    Abstract: A manufacturably improved asymmetric stripline enhanced aperture coupler (10) is provided including a first non-transverse electromagnetic (non-TEM) field which couples an asymmetric stripline transmission line (22) to a coupling conductor (19) through a first aperture (17) in a first ground plane (16). The coupler (10) suppresses a second non-TEM field formed as an image on a second ground plane (15) by reducing the current flow on the second ground plane (15) using the asymmetric stripline transmission line (22) with increased coupling between a stripline conductor (12) and first ground plane (16) relative to coupling between stripline conductor (12) and second ground plane (15), particularly in the vicinity of the second non-TEM field using second aperture (14). The second non-TEM field is suppressed so as to enhance the coupling effect of the first non-TEM field between asymmetric stripline transmission line (22) and a coupling conductor (19).
    Type: Grant
    Filed: June 23, 1995
    Date of Patent: July 2, 1996
    Assignee: Motorola, Inc.
    Inventors: Stephen L. Kuffner, Eric L. Krenz
  • Patent number: 5532708
    Abstract: A printed circuit board antenna is provided which includes an electronic switch (38) whereby a single compact radiating structure consisting of a split dipole antenna (10) with associated balun structure (11) may be selectively driven in either of two modes to provide orthogonal polarization and pattern diversity: as a split dipole antenna with a quarter wave balun relying on the split dipole antenna (10) as the radiating element; or as a top-loaded monopole relying on the quarter wave balun structure (11) as the radiating element against a ground plane (12). Orthogonal polarization and pattern diversity are achieved as a result of the mutually perpendicular orientations of the split dipole antenna (10) and its integral balun structure (11).
    Type: Grant
    Filed: March 3, 1995
    Date of Patent: July 2, 1996
    Assignee: Motorola, Inc.
    Inventors: Eric L. Krenz, David J. Tammen
  • Patent number: 5524278
    Abstract: A method and apparatus is provided for facilitating scanning of radio control channels where a plurality of communication systems conjunctively cover the same area. A subscriber unit receives an overhead message train on a control channel which includes a channel count representing the number of control channels of a communication system. Subsequently, the subscriber unit scans a channel count number of control channels to tune to a control channel being used by a communication system having coverage for the subscriber unit. This scanning of control channels starts with a predetermined start control channel which corresponds to the logical number of the control channel in a sequence of control channels which is after the channel count control channel. In addition, an apparatus may be provided to transmit, in the overhead message train, a subscriber unit control message with an address indicating that a communication system is operating within a coverage area.
    Type: Grant
    Filed: February 6, 1992
    Date of Patent: June 4, 1996
    Assignee: Motorola, Inc.
    Inventors: James M. Williams, Robert F. D'Avello, Robert K. Krolopp
  • Patent number: 5509000
    Abstract: A method and apparatus for routing information within a communication system (100) is based upon evaluating various attributes (310) of the information to be routed. The methodology employs processing steps including, but not limited to receiving a message (300) having a key (304) and a first set of message attributes (310), each attribute having a value. Extracting the key (304) from the message to index a data base (400) in order to retrieve records (410) having the key and containing a representation of a logic function (406) that describes a second set of message attributes. The first set of attributes values are applied to the logic function (406) of the first retrieved record to determine whether the function is true or false. If true, that data base record is selected for use in routing the information. Otherwise, the first set of attribute values are applied to the logic functions of each indexed data base record (410) until a true condition is encountered.
    Type: Grant
    Filed: June 10, 1994
    Date of Patent: April 16, 1996
    Assignee: Motorola, Inc.
    Inventor: Lewis B. Oberlander
  • Patent number: 5508708
    Abstract: A method and apparatus for determining the location of a communication unit in a CDMA system includes in a first embodiment, sending a location request via a spread spectrum signal to the subscriber (140), and receiving in return a subscriber signal including a response message showing a receive time of a particular symbol of the base's spreading sequence and a transmit time of a particular symbol of the subscriber's spreading sequence. The base (130), along with other receiving base(s) (140), also receives a predetermined symbol of the subscriber spreading sequence, and each determines a respective receive time of the predetermined symbol. The received information is then processed, along with known base location and delay information, to determine the subscriber location. If insufficient number of bases are capable of communicating with the subscriber, for example due to high loading/interference, auxiliary bases (121) are also provided for receiving from or transmitting to the subscriber.
    Type: Grant
    Filed: May 8, 1995
    Date of Patent: April 16, 1996
    Assignee: Motorola, Inc.
    Inventors: Amitava Ghosh, John D. Reed, Walter J. Rozanski, Jr., Kevin A. Buford
  • Patent number: 5508665
    Abstract: An oscillator arranged to operate at an oscillation frequency includes a resonant structure 137, preferably a coaxial resonator, selected to resonate at a frequency, and an impedance 210, preferably a transistor 101 based common collector circuit, parallel coupled to said resonant structure 137, having a negative real part with a real magnitude and an imaginary part with an imaginary magnitude, said real magnitude being a function of said imaginary magnitude, said imaginary magnitude selected such that said real magnitude falls within 50% of a maximum at the oscillation frequency.
    Type: Grant
    Filed: October 31, 1994
    Date of Patent: April 16, 1996
    Assignee: Motorola, Inc.
    Inventors: Yiu K. Chan, Krista Tindorf
  • Patent number: 5506863
    Abstract: A communication unit for use in a communication system is provided which includes a hopping mechanism which hops communication frames over a plurality of carrier frequencies according to a predetermined hopping pattern. At least one of the communication frames preferably includes a synchronization channel time slot having data bits from which the predetermined hopping pattern may be derived. In addition, a communication unit is provided which includes a signal acquisition mechanism for initially acquiring a predetermined hopping pattern that specifies the sequence over which hop frames are hopped over a plurality of carrier frequencies. Also, this communication unit includes a hopping mechanism for hopping receiving frequency according to the predetermined hopping pattern such that a control channel may be detected. In an alternative embodiment, either communication unit may derive the predetermined hopping pattern from detected global position satellite information.
    Type: Grant
    Filed: August 25, 1993
    Date of Patent: April 9, 1996
    Assignee: Motorola, Inc.
    Inventors: Reuven Meidan, Duane C. Rabe, Michael D. Kotzin
  • Patent number: D373566
    Type: Grant
    Filed: June 30, 1995
    Date of Patent: September 10, 1996
    Assignee: Motorola, Inc.
    Inventors: Roman P. Rak, William E. Fenton
  • Patent number: D373567
    Type: Grant
    Filed: June 30, 1995
    Date of Patent: September 10, 1996
    Inventors: Roman P. Rak, William E. Fenton