Patents by Inventor Thomas A. Sexton

Thomas A. Sexton has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7269207
    Abstract: A method and device for estimating a target chip index value in a code-division multiple access receiver. The receiver receives signals from a transmitter that uses a plurality of transmitted chips for data transmission through a plurality of multipath channels. As each channel is expressible as a channel impulse response at a given instant in time, the impulse response can be sampled and the samples indexed by a plurality of delay sample indices. The target chip index value can be determined based on the first moment of the delay sample indices over an impulse response.
    Type: Grant
    Filed: February 5, 2003
    Date of Patent: September 11, 2007
    Assignee: Nokia Corporation
    Inventors: Jorma Lilleberg, Kim Rounioja, Thomas A. Sexton
  • Patent number: 7003055
    Abstract: A method and apparatus provide a systolic equalizer for Viterbi equalization of an 8-PSK signal distorted by passage through a communication channel. The systolic equalizer architecture is scalable to process, as examples, four, eight and 16 state received signals. An equalizer in accordance with this invention includes a logical arrangement of a plurality of instantiations of locally coupled processing elements forming a systolic array for processing in common received signal samples having distortion induced by passage through a communication channel. The equalizer outputs soft values for input to a decoder, the soft values representing an approximation of maximum a posteriori (MAP) probabilities. A trellis search procedure is employed to reconstruct estimates of a received signal sequence based on a reduced number of states. The reduced number of states is represented by a plurality of groups determined by partitioning a symbol constellation such that there are fewer groups than possible symbols.
    Type: Grant
    Filed: October 25, 2002
    Date of Patent: February 21, 2006
    Assignee: Nokia Corporation
    Inventors: Thomas A. Sexton, Jari Parviainen
  • Patent number: 6956839
    Abstract: Apparatus, and an associated method, for a radio, such as cellular, communication system to facilitate communications between a mobile station and the network infrastructure. When the mobile station registers in the communication system, a dedicated reverse-link channel is allocated to facilitate communications of packet data between the mobile station and the network infrastructure. By providing dedicated channels, the mobile station becomes functionally connected to the network infrastructure and are analogous to a hard wired connection of a computer in a local area network.
    Type: Grant
    Filed: April 26, 2002
    Date of Patent: October 18, 2005
    Assignee: Nokia Corporation
    Inventors: Thomas A. Sexton, George Fry
  • Publication number: 20040240591
    Abstract: A method and apparatus provide a systolic equalizer for Viterbi equalization of an 8-PSK signal distorded by passage through a communication channel. The systolic equalizer architecture is scalable to process, as examples, four, eight and 16 state received signals. An equalizer (10) in accordance with this invention includes a logical arrangement of a plurality of instantiations of locally coupled processing elements (12) forming a systolic array for processing in common received signal samples having distortion induced by passage through a communication channel. The equalizer outputs soft values for input to a decoder, the soft values representing an approximation of maximum a posteriori (MAP) probabilities. A trellis search procedure is employed to reconstruct estimates of a received signal sequence based on a reduced number of states. The reduced numbe of states is represented by a plurality of groups determined by partioning a symbol constellation such that there are fewer groups than possible symbols.
    Type: Application
    Filed: July 6, 2004
    Publication date: December 2, 2004
    Inventors: Thomas A. Sexton, Jari Parviainen
  • Publication number: 20040151236
    Abstract: A method and device for estimating a target chip index value in a code-division multiple access receiver. The receiver receives signals from a transmitter that uses a plurality of transmitted chips for data transmission through a plurality of multipath channels. As each channel is expressible as a channel impulse response at a given instant in time, the impulse response can be sampled and the samples indexed by a plurality of delay sample indices. The target chip index value can be determined based on the first moment of the delay sample indices over an impulse response.
    Type: Application
    Filed: February 5, 2003
    Publication date: August 5, 2004
    Applicant: Nokia Corporation
    Inventors: Jorma Lilleberg, Kim Rounioja, Thomas A. Sexton
  • Patent number: 6614772
    Abstract: Apparatus, and an associated method, for a radio, such as cellular, communication system to facilitate communications between a mobile station and the network infrastructure. When the mobile station registers in the communication system, a dedicated reverse-link channel is allocated to facilitate communications of packet data between the mobile station and the network infrastructure. By providing dedicated channels, the mobile station becomes functionally connected to the network infrastructure and are analogous to a hard wired connection of a computer in a local area network.
    Type: Grant
    Filed: March 1, 1999
    Date of Patent: September 2, 2003
    Assignee: Nokia Corporation
    Inventors: Thomas A. Sexton, George Fry
  • Publication number: 20030081569
    Abstract: A cellular communications system includes a plurality of mobile stations located within at least one cell; a base transceiver station (BTS) for servicing the cell; a base station controller (BSC) coupled to the BTS; and a Call Admission processor coupled to the BTS for receiving a call admission request from mobile stations located in the cell served by the BTS. The processor, which could be co-located with the BSC, grants cellular communications system resources to mobile stations based at least in part on a level of service required by the mobile stations and on a location of the mobile stations within the cell. For a mobile station having a high bandwidth requirement and that is determined to be located at the edge of the cell, the mobile station is preferentially granted system resources by being assigned a plurality of time slots per frame for forming one radio information block, and is operated with a non-convolutional modulation format and with turbo channel coding.
    Type: Application
    Filed: October 25, 2001
    Publication date: May 1, 2003
    Applicant: Nokia Corporation
    Inventors: Thomas A. Sexton, Panayiotis D. Papadimitriou, Hannu Vilpponen, Prabodh Varshney
  • Publication number: 20030048838
    Abstract: A method and apparatus for reducing a number of calculations during equalization is disclosed. A burst is processed using weak equalization and with strong equalization when a predetermined criteria is met. By performing weak equalization rather than strong equalization when a predetermined condition is met the number of calculation may be reduced for most bursts. In addition, in one embodiment of the present invention, if strong equalization fails, then turbo equalization is used. Equalizer selection for subsequent bursts in block may occur after review of the equalization results of the first burst in a block.
    Type: Application
    Filed: September 11, 2001
    Publication date: March 13, 2003
    Applicant: Nokia Corporation
    Inventors: Thomas A. Sexton, Hannu Vilpponen
  • Patent number: 6510174
    Abstract: Apparatus, and an associated method, for facilitating selection of link parameters associated with a communication signal transmitted in a radio communication system, such as a GSM (global system for mobile communications) system which provides for GPRS (general packet radio service). Uplink sounding bursts are generated by a mobile station and transmitted to the network infrastructure of the radio communication system. The uplink sounding bursts are analyzed to determine channel conditions upon which the uplink sounding bursts are transmitted. Responsive thereto, selection is made of one or more link parameters of which subsequently-generated GPRS, or other, messages to be transmitted by the mobile station are to be formed. Indications of the selection are provided to the mobile station to permit formation of the subsequently-generated messages in manners which conform with the selected link parameter.
    Type: Grant
    Filed: November 30, 1999
    Date of Patent: January 21, 2003
    Assignee: Nokia Corporation
    Inventors: Thomas A. Sexton, Antti Lappetelainen
  • Publication number: 20020159433
    Abstract: Apparatus, and an associated method, for a radio, such as cellular, communication system to facilitate communications between a mobile station and the network infrastructure. When the mobile station registers in the communication system, a dedicated reverse-link channel is allocated to facilitate communications of packet data between the mobile station and the network infrastructure. By providing dedicated channels, the mobile station becomes functionally connected to the network infrastructure and are analogous to a hard wired connection of a computer in a local area network.
    Type: Application
    Filed: April 26, 2002
    Publication date: October 31, 2002
    Inventors: Thomas A. Sexton, George Fry
  • Patent number: 6349208
    Abstract: A method, and associated apparatus, predicts the likelihood of successful effectuation of handover in a cellular communication system. Handover is permitted only if the predicted likelihood is at least as great as a minimum threshold. If the predicted likelihood is less than the minimum threshold, a request is made to increase the coding rate of control signals used pursuant to the handover procedure. Handover is permitted only when the likelihood of success is predicted to be high. Thereby, the possibility of loss of communications during handover procedures is reduced.
    Type: Grant
    Filed: April 28, 1999
    Date of Patent: February 19, 2002
    Assignee: Nokia Corporation
    Inventors: Thomas A. Sexton, Riku P. Pirhonen
  • Patent number: 6094428
    Abstract: In a communication system where a continuous reverse channel transmission is utilized by redundant transmission of Walsh codes, a current transmission rate is modulated onto Walsh code polarity. In particular, a remote unit operating at a particular transmission rate utilizing a continuous reverse channel transmission modulates the transmission rate by setting the polarity of each Walsh code depending upon the current or future data traffic channel rate. In communication systems where a Reference Coherent (RC) type transmission is utilized, the particular transmission rate is modulated onto the reference symbols (501-517) by setting the reference symbols (501-517) equal to a binary "1" or "0".
    Type: Grant
    Filed: April 30, 1997
    Date of Patent: July 25, 2000
    Assignee: Motorola, Inc.
    Inventors: Eugene J. Bruckert, Thomas A. Sexton
  • Patent number: 5818887
    Abstract: The method includes acquiring a signal (501); inputting (502), at a first time, a received symbol to a demodulator having a plurality of outputs to produce a set of early outputs; inputting (504), at a second time, the received symbol to the demodulator to produce a set of on-time outputs; inputting (505), at a third time, the received symbol to the demodulator to produce a set of late outputs; and comparing (506) at least one output in the set of early outputs with at least one output in the set of late outputs to produce a timing measure.
    Type: Grant
    Filed: July 26, 1996
    Date of Patent: October 6, 1998
    Assignee: Motorola, Inc.
    Inventors: Thomas A. Sexton, Fuyun Ling, Kenneth A. Stewart
  • Patent number: 5790596
    Abstract: The method includes receiving a signal comprising a received frame, the received frame having a plurality of received symbols and having a received information portion and a received frame quality indicator; storing at least one of the plurality of received symbols in a memory; demodulating the received information portion to form a demodulated information portion and demodulating the received frame quality indicator to form a demodulated frame quality indicator, the demodulated information portion and the demodulated frame quality indicator comprising a demodulated frame; re-encoding at least a portion of the demodulated frame to form an encoded frame, the encoded frame having a plurality of encoded symbols; comparing one of the plurality of encoded symbols with the at least one of the plurality of received symbols stored in the memory; and based on the comparison, estimating the channel parameter.
    Type: Grant
    Filed: March 15, 1996
    Date of Patent: August 4, 1998
    Assignee: Motorola, Inc.
    Inventor: Thomas A. Sexton
  • Patent number: 5781583
    Abstract: A method for transmitting a communication signal (20) having a data rate over a plurality of spread spectrum traffic channels includes determining a first number of traffic channels required to transmit the communication signal at the data rate, and determining a second number of traffic channels (502) available for transmitting the communication signal (20). In response to a comparison of the first number of traffic channels to the second number of traffic channels, a first traffic channel (54) for transmitting a first portion of the communication signal (50, 51) and a second traffic channel (56) for transmitting a second portion of the communication signal (52, 53) are selected from the. second number of traffic channels (502). The selection of the first traffic channel (54) is non deterministic of the selection of the second traffic channel (56).
    Type: Grant
    Filed: January 19, 1996
    Date of Patent: July 14, 1998
    Assignee: Motorola, Inc.
    Inventors: Eugene J. Bruckert, Thomas A. Sexton
  • Patent number: 5778030
    Abstract: Power control in a spread spectrum communication system takes place by determining a speed of a remote unit (405) and assigning as a power-control threshold a target threshold based on the determined speed (410). An instantaneous threshold value is created (415) based on frame-quality information and the target threshold. An energy of a power-control group transmitted (430) from a remote unit is compared to the instantaneous threshold value and a power-adjustment command is determined. The power-adjustment command is transmitted to the remote unit instructing the remote unit to adjust its power accordingly.
    Type: Grant
    Filed: March 15, 1996
    Date of Patent: July 7, 1998
    Assignee: Motorola, Inc.
    Inventors: Eugene J. Bruckert, Thomas A. Sexton, Robert T. Love, William R. Bayer
  • Patent number: 5687198
    Abstract: A receiver (200, 400) implements improved channel estimation. The receiver (200, 400) demodulates a transmitted signal, and makes an initial channel estimate (115). The receiver (200, 400) then makes a hard decision (301) as to whether the channel estimate was correct and groups samples representing the decision. A vector sum of the group of samples is computed (302), and each sample is compared to the vector sum (303). The sample having the largest projection on the vector sum is retained (304), and the other samples are considered noise, and are thus discarded (305). After obtaining a predetermined number of retained samples (306), the retained samples are used to generate an new channel estimate (226). Since the noisy estimates are discarded, the new channel estimate (226) contains fewer errors than the initial channel estimate (115). The new channel estimate (226) is used to generate decoded data (250).
    Type: Grant
    Filed: January 4, 1996
    Date of Patent: November 11, 1997
    Assignee: Motorola, Inc.
    Inventors: Thomas A. Sexton, Fuyun Ling
  • Patent number: 5640431
    Abstract: A method and apparatus for improved offset frequency estimation includes in a first embodiment a receiver (100) for coherent reception of a signal having known reference information, the receiver including an extractor (106) for extracting the reference information (107) from the signal, and an offset frequency estimator (110). The offset frequency estimator (110) includes a filter (121) for filtering the reference information and outputting a filtered reference sequence; a correlator (122, 124) for correlating the filtered reference sequence against a predetermined reference signal to form correlation values; and a peak detector (126) for determining an offset frequency estimate (131) from the correlation values. Other embodiments are also shown.
    Type: Grant
    Filed: March 10, 1995
    Date of Patent: June 17, 1997
    Assignee: Motorola, Inc.
    Inventors: Eugene J. Bruckert, Fuyun Ling, Thomas A. Sexton
  • Patent number: 5619524
    Abstract: A method and apparatus is provided for facilitating coherent communication reception. A received reference symbol coded spread spectrum communication signal is despread with a spreading code to derive a stream of reference samples and a stream of data samples. The channel response is estimated by utilizing the stream of reference samples. An offset frequency detector determines an offset to be applied to the received signal via a frequency locked loop, while a timing control compensates for slow timing drift and fast fading based on power estimates derived from the stream of reference samples and/or the stream of data samples. A rate estimator determines the rate at which the information was encoded, and the rate information is used to optimize the timing control, frequency offset detector and channel estimator. Thus an improved detection of estimated data symbols from the stream of received data samples is provided.
    Type: Grant
    Filed: February 28, 1995
    Date of Patent: April 8, 1997
    Assignee: Motorola, Inc.
    Inventors: Fuyun Ling, Thomas A. Sexton, Gene Bruckert
  • Patent number: 5212715
    Abstract: In frequency-hopping spread-spectrum systems, it is necessary to maintain frequency and bit synchronization (sync) between the transmitter and receiver in order to maintain quality data recovery at the receiver. A protocol is described which includes a synthesizer lock field (109) to allow frequency sync, a clock sync field (123) to achieve quick clock sync, and a data sync field (125) to provide data sync. Other fields are provided in the protocol to allow both voice (141) and data (127) transmissions, inband signalling (139), and error correction (143). A method and apparatus, driven by a microprocessor (303) and ASIC (301) combination, are described that generate and transmit this protocol.
    Type: Grant
    Filed: January 25, 1991
    Date of Patent: May 18, 1993
    Assignee: Motorola, Inc.
    Inventors: William F. Pickert, James A. McDonald, Thomas A. Sexton, Charles J. Malek