Patents by Inventor Da-Shan Shiu

Da-Shan Shiu 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: 8059584
    Abstract: Techniques for inter-frequency neighbor list searching are disclosed. Embodiments disclosed herein address the need for inter-frequency neighbor list searching. In one embodiment, a searcher is deployed to search a PN space with a first set of search parameters and to return search results. A subset of those results is selected, along with a previously saved search result, to form a set of PN locations for a second search. The second search is performed on a window around each of the PN locations, using a second set of search parameters. The maximum peak from the second search is saved for use in future iterations. In one embodiment, the subset is selected as the highest energy level peaks from the first search. In one embodiment, if a maximum peak is deemed to correspond to a valid base station when the position of that maximum peak is within a pre-determined time offset from a previous maximum peak.
    Type: Grant
    Filed: February 12, 2008
    Date of Patent: November 15, 2011
    Assignee: QUALCOMM Incorporated
    Inventors: Da-shan Shiu, Thomas B Wilborn, Roland Reinhard Rick, Srinivasa Rao Nagaram, Chalapathi Rao Emani, Ramachandran Gurumoorthy, Jesus Chao, Steve Doerfler, Peter Ang, Srividya Kunisetti, Gwang-Hyun Gho, Thomas Nelson Bailey
  • Patent number: 8023988
    Abstract: Techniques to more efficiently control the transmit power for a data transmission that uses a number of formats (e.g., rates, transport formats). Different formats for a given data channel (e.g., transport channel) may require different target SNIRs to achieved a particular BLER. In one aspect, individual target BLER may be specified for each format of each data channel. In another aspect, various power control schemes are provided to achieve different target SNIRs for different formats. In a first power control scheme, multiple individual outer loops are maintained for multiple formats. For each format, its associated outer loop attempts to set the target SNIR such that the target BLER specified for that format is achieved. In a second power control scheme, multiple individual outer loops are maintained and the base station further applies different adjustments to the transmit power levels for different formats.
    Type: Grant
    Filed: April 28, 2008
    Date of Patent: September 20, 2011
    Assignee: QUALCOMM Incorporated
    Inventors: Da-Shan Shiu, Serge Willenegger, Richard Chi, Parvathanathan Subrahmanya, Chih-Ping Hsu
  • Patent number: 8014473
    Abstract: Techniques for detecting received sequences when certain signaling characteristics (e.g., transport formats, rates) are not known a priori at the receiver. In one method, a sequence for a transmitted message is received, and a metric value is computed for each of a number of hypothesized messages corresponding to a number of hypotheses for the unknown signaling characteristic of the transmitted message. The metric value is computed based on a MAP metric derived to approximately maximize a joint a posteriori probability between the received sequence and the hypothesized messages. The hypothesized message having the best metric value is selected as the transmitted message. The specific form of the MAP metric is dependent on the particular signaling scheme used to map the message to its corresponding sequence, and may be used for blind transport format detection (BTFD) in a W-CDMA system and blind rate detection in an IS-95 CDMA system.
    Type: Grant
    Filed: April 12, 2001
    Date of Patent: September 6, 2011
    Assignee: Qualcomm Incorporated
    Inventors: Richard Chi, Da-Shan Shiu
  • Publication number: 20110158293
    Abstract: Noise measurements are made within a fraction of a single symbol period of a longest orthogonal code symbol. A control processor identifies an unoccupied code having a spreading factor that is less than a longest spreading factor for the system. A despreader measures symbol energy based on the unoccupied code and a noise estimator generates noise estimations based on the measured symbol energies.
    Type: Application
    Filed: March 11, 2011
    Publication date: June 30, 2011
    Applicant: QUALCOMM Incorporated
    Inventors: Da-Shan Shiu, Durga Prasad Malladi, Srikrishna Bhashyam
  • Patent number: 7966032
    Abstract: Techniques for power control that avoids outer loop wind-up are disclosed. In one aspect, wind-up of a target power level is detected, and the target power level is modified in response. In another aspect, unwinding of the target power level is detected, after which the target power level is determined without considering wind-up. Various other aspects are also presented, including wind-up and unwinding detection procedures, and target power level modification procedures. These aspects have the benefit of reducing the time that transmit power exceeds that which is necessary, thus increasing system capacity and performance, and mitigating misallocation of system resources.
    Type: Grant
    Filed: November 1, 2005
    Date of Patent: June 21, 2011
    Assignee: QUALCOMM Incorporated
    Inventors: Richard Chi, Da-Shan Shiu, Nitin Kasturi, Parvathanathan Subrahmanya
  • Patent number: 7734309
    Abstract: Techniques for power control that avoids outer loop wind-up are disclosed. In one aspect, wind-up of a target power level is detected, and the target power level is modified in response. In another aspect, unwinding of the target power level is detected, after which the target power level is determined without considering wind-up. Various other aspects are also presented, including wind-up and unwinding detection procedures, and target power level modification procedures. These aspects have the benefit of reducing the time that transmit power exceeds that which is necessary, thus increasing system capacity and performance, and mitigating misallocation of system resources.
    Type: Grant
    Filed: May 18, 2007
    Date of Patent: June 8, 2010
    Assignee: QUALCOMM Incorported
    Inventors: Richard Chi, Da-Shan Shiu, Nitin Kasturi, Parvathanathan Subrahmanya
  • Patent number: 7702350
    Abstract: Techniques to quickly adjust an SIR target toward a final value needed to achieve a specified target BLER for a data transmission. The outer loop may be implemented with multiple modes. The SIR target may be maintained fixed in a hold mode, adjusted in large down steps to speed up convergence in an acquisition mode, and adjusted by a small down step and a large up step for good and erased blocks, respectively, in a tracking mode. Various schemes may be used to adjust the SIR target by larger down steps in the acquisition mode. These schemes may be used even if data is transmitted intermittently, the target BLER is set to a low value, and/or one or multiple transport channels are used for data transmission. The SIR target may be boosted by a particular amount upon transitioning from the acquisition mode to the tracking mode.
    Type: Grant
    Filed: March 12, 2003
    Date of Patent: April 20, 2010
    Assignee: QUALCOMM Incorporated
    Inventors: Hyukjun Oh, Luca Blessent, Chih-Ping Hsu, Da-Shan Shiu, Nitin Kasturi, Parvathanathan Subrahmanya
  • Patent number: 7664519
    Abstract: Techniques are provided to control the transmit power for data transmission on multiple transport channels having different signal quality (SIR) targets. A single SIR target is maintained for all transport channels, and this SIR target is adjusted based only on active transport channels. For each update interval, a data processor processes at least one data block received in the current update interval on at least one of the transport channels and provides the status of each received data block. A controller increases the SIR target based on an up step if any received data block is erased and decreases the SIR target based on a down step if all received data blocks are good. If any received data block is erased, the down step used to adjust the SIR target may be set to the smallest down step size required by all transport channels with erased data blocks.
    Type: Grant
    Filed: December 30, 2003
    Date of Patent: February 16, 2010
    Assignee: QUALCOMM Incorporated
    Inventors: Chih-Ping Hsu, Parvathanathan Subrahmanya, Da-shan Shiu, Hyukjun Oh, Christopher C. Riddle, Nitin Kasturi
  • Patent number: 7653028
    Abstract: Multiple access interference may be substantially removed by introducing a near-far situation in which a near mobile and a far mobile (“near” and “far” based on signal strength) are selected, resources allocated among these and other mobiles, and the data is packetized for transmission during a transmission interval such that the data intended for the far mobile is transmitted along with the data intended for the near mobile. Forward link signals are then appropriately scheduled. Signals intended for the far mobile and the near mobile are decoded from the composite signal received at the near mobile. The signal intended for the far mobile is then removed from the composite signal received at the near mobile.
    Type: Grant
    Filed: October 3, 2002
    Date of Patent: January 26, 2010
    Inventors: Da-shan Shiu, Durga P. Malladi
  • Patent number: 7583756
    Abstract: Techniques to filter pilot symbols for a pilot in an “adaptive” manner to provide an improved estimate of the response of a communication channel. A received signal may experience different channel conditions at different times, and different multipaths may also experience different channel conditions even when received close in time. A pilot filter with an adaptive response is used to provide an improved estimate of the channel response. Various adaptive pilot filtering schemes may be used. In a first scheme, the channel conditions are estimated based on the quality of the received pilot. In a second scheme, the channel conditions are estimated based on the quality of the pilot estimates (i.e., the filtered pilot symbols). For each scheme, a particular filter response is selected based on the estimated quality of either the received pilot or the pilot estimates.
    Type: Grant
    Filed: June 11, 2007
    Date of Patent: September 1, 2009
    Assignee: Qualcomm Incorporated
    Inventors: Parvathanathan Subrahmanya, Da-shan Shiu, Avneesh Agrawal
  • Publication number: 20080233995
    Abstract: Techniques to more efficiently control the transmit power for a data transmission that uses a number of formats (e.g., rates, transport formats). Different formats for a given data channel (e.g., transport channel) may require different target SNIRs to achieved a particular BLER. In one aspect, individual target BLER may be specified for each format of each data channel. In another aspect, various power control schemes are provided to achieve different target SNIRs for different formats. In a first power control scheme, multiple individual outer loops are maintained for multiple formats. For each format, its associated outer loop attempts to set the target SNIR such that the target BLER specified for that format is achieved. In a second power control scheme, multiple individual outer loops are maintained and the base station further applies different adjustments to the transmit power levels for different formats.
    Type: Application
    Filed: April 28, 2008
    Publication date: September 25, 2008
    Inventors: Da-shan Shiu, Serge Willenegger, Richard Chi, Parvathanathan Subrahmanya, Chih-Ping Hsu
  • Publication number: 20080212553
    Abstract: Techniques for improved low latency frequency switching are disclosed. In one embodiment, a controller receives a frequency switch command and generates a frequency switch signal at a time determined in accordance with a system timer. In another embodiment, gain calibration is initiated subsequent to the frequency switch signal delayed by the expected frequency synthesizer settling time. In yet another embodiment, DC cancellation control and gain control are iterated to perform gain calibration, with signaling to control the iterations without need for processor intervention. Various other embodiments are also presented. Aspects of the embodiments disclosed may yield the benefit of reducing latency during frequency switching, allowing for increased measurements at alternate frequencies, reduced time spent on alternate frequencies, and the capacity and throughput improvements that follow from minimization of disruption of an active communication session and improved neighbor selection.
    Type: Application
    Filed: October 25, 2007
    Publication date: September 4, 2008
    Applicant: QUALCOMM Incorporated
    Inventors: Da-shan Shiu, Li Zhang, Eugene Sy, David Malonado, Upkar Dhaliwal
  • Publication number: 20080215573
    Abstract: Techniques for inter-frequency neighbor list searching are disclosed. Embodiments disclosed herein address the need for inter-frequency neighbor list searching. In one embodiment, a searcher is deployed to search a PN space with a first set of search parameters and to return search results. A subset of those results is selected, along with a previously saved search result, to form a set of PN locations for a second search. The second search is performed on a window around each of the PN locations, using a second set of search parameters. The maximum peak from the second search is saved for use in future iterations. In one embodiment, the subset is selected as the highest energy level peaks from the first search. In one embodiment, if a maximum peak is deemed to correspond to a valid base station when the position of that maximum peak is within a pre-determined time offset from a previous maximum peak.
    Type: Application
    Filed: February 12, 2008
    Publication date: September 4, 2008
    Applicant: QUALCOMM INCORPORATED
    Inventors: Da-shan Shiu, Thomas B. Wilborn, Roland Rick, Srinivasa Rao Nagaram, Chalapathi Rao Emani, Ramachandran Gurumoorthy, Jesus Chao, Steve Doerfler, Peter Ang, Srividya Kunisetti, Gwang-Hyun Gho, Thomas Bailey
  • Patent number: 7420947
    Abstract: A method and apparatus for using information about a mobile terminal's location relative to a base station can improve performance of a communication system. In addition, information about the mobile terminal's velocity relative to the base station may be used to improve performance of the communication system. The location information may be used to estimate a nominal PN offset, and a set of PN offset to use, for processing communication signals. The velocity information may be used to estimate a nominal frequency of the communication signals.
    Type: Grant
    Filed: August 28, 2003
    Date of Patent: September 2, 2008
    Assignee: Qualcomm Incorporated
    Inventors: Andrew Sendonaris, Da-Shan Shiu, David Patterson, Pavathanathan Subrahmanya, Daisuke Terasawa
  • Publication number: 20080130731
    Abstract: Noise measurements are made within a fraction of a single symbol period of a longest orthogonal code symbol. A control processor identifies an unoccupied code having a spreading factor that is less than a longest spreading factor for the system. A despreader measures symbol energy based on the unoccupied code and a noise estimator generates noise estimations based on the measured symbol energies.
    Type: Application
    Filed: July 23, 2007
    Publication date: June 5, 2008
    Inventors: Da-shan Shiu, Durga P. Malladi, Srikrishna Bhashyam
  • Patent number: 7376438
    Abstract: Techniques to more efficiently control the transmit power for a data transmission that uses a number of formats (e.g., rates, transport formats). Different formats for a given data channel (e.g., transport channel) may require different target SNIRs to achieved a particular BLER. In one aspect, individual target BLER may be specified for each format of each data channel. In another aspect, various power control schemes are provided to achieve different target SNIRs for different formats. In a first power control scheme, multiple individual outer loops are maintained for multiple formats. For each format, its associated outer loop attempts to set the target SNIR such that the target BLER specified for that format is achieved. In a second power control scheme, multiple individual outer loops are maintained and the base station further applies different adjustments to the transmit power levels for different formats.
    Type: Grant
    Filed: October 12, 2005
    Date of Patent: May 20, 2008
    Assignee: QUALCOMM Incorporated
    Inventors: Da-shan Shiu, Serge Willenegger, Richard Chi, Parvathanathan Subrahmanya, Chih-Ping Hsu
  • Patent number: 7330452
    Abstract: Techniques for inter-frequency neighbor list searching are disclosed. Embodiments disclosed herein address the need for inter-frequency neighbor list searching. In one embodiment, a searcher is deployed to search a PN space with a first set of search parameters and to return search results. A subset of those results are selected, along with a previously saved search result, to form a set of PN locations for a second search. The second search is performed on a window around each of the PN locations, using a second set of search parameters. The maximum peak from the second search is saved for use in future iterations. In one embodiment, the subset is selected as the highest energy level peaks from the first search. In one embodiment, if a maximum peak is deemed to correspond to a valid base station when the position of that maximum peak is within a pre-determined time offset from a previous maximum peak.
    Type: Grant
    Filed: June 13, 2003
    Date of Patent: February 12, 2008
    Assignee: QUALCOMM Incorporated
    Inventors: Da-shan Shiu, Thomas B. Wilborn, Roland Rick, Srinivasa Rao Nagaram, Chalapathi Rao Emani, Ramachandran Gurumoorthy, Jesus Chao, Steve Doerfler, Peter Ang, Srividya Kunisetti, Gwang-Hyun Gho, Thomas Bailey
  • Publication number: 20070298739
    Abstract: Techniques for segmented CDMA searching are disclosed. In one aspect, a searcher comprises a plurality of storage elements selectable for performing a plurality of segmentable search tasks, each storage element operable for storage of and access to state information for one of the plurality of search tasks. In another aspect, a first search task is interrupted in progress, the state information for the first task is stored, a second search task is performed, and the first search task is continued using the stored state information. In yet another aspect, a search task is segmented into smaller search segments, sized to fit within contiguous available time in the searcher. Various other aspects of the invention are also presented. These aspects have the benefit of circuit area and search-time efficiency which translate into reduced costs, increased standby time, increased acquisition speed, higher quality signal transmission, increased data throughput, decreased power, and improved overall system capacity.
    Type: Application
    Filed: May 8, 2007
    Publication date: December 27, 2007
    Applicant: QUALCOMM Incorporated
    Inventors: Subramanya Rao, Da-Shan Shiu, Jeremy Lin, Jeong Kim
  • Patent number: 7307480
    Abstract: Techniques for improved low latency frequency switching are disclosed. In one embodiment, a controller receives a frequency switch command and generates a frequency switch signal at a time determined in accordance with a system timer. In another embodiment, gain calibration is initiated subsequent to the frequency switch signal delayed by the expected frequency synthesizer settling time. In yet another embodiment, DC cancellation control and gain control are iterated to perform gain calibration, with signaling to control the iterations without need for processor intervention. Various other embodiments are also presented. Aspects of the embodiments disclosed may yield the benefit of reducing latency during frequency switching, allowing for increased measurements at alternate frequencies, reduced time spent on alternate frequencies, and the capacity and throughput improvements that follow from minimization of disruption of an active communication session and improved neighbor selection.
    Type: Grant
    Filed: April 24, 2003
    Date of Patent: December 11, 2007
    Assignee: QUALCOMM Incorporated
    Inventors: Da-shan Shiu, Li Zhang, Eugene Sy
  • Publication number: 20070230544
    Abstract: Techniques to filter pilot symbols for a pilot in an “adaptive” manner to provide an improved estimate of the response of a communication channel. A received signal may experience different channel conditions at different times, and different multipaths may also experience different channel conditions even when received close in time. A pilot filter with an adaptive response is used to provide an improved estimate of the channel response. Various adaptive pilot filtering schemes may be used. In a first scheme, the channel conditions are estimated based on the quality of the received pilot. In a second scheme, the channel conditions are estimated based on the quality of the pilot estimates (i.e., the filtered pilot symbols). For each scheme, a particular filter response is selected based on the estimated quality of either the received pilot or the pilot estimates.
    Type: Application
    Filed: June 11, 2007
    Publication date: October 4, 2007
    Applicant: QUALCOMM INCORPORATED
    Inventors: Parvathanathan Subrahmanya, Da-shan Shiu, Avneesh Agrawal