Patents by Inventor Xiliang Luo

Xiliang Luo 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).

  • Publication number: 20150131585
    Abstract: A system and method for facilitating resource management in OFDM systems is provided. The system permits different and flexible resource cell metric operations levels (e.g. uplink load management, admission control, congestion control, signal handoff control) for different sub-bands. For the uplink load management, there are multiple distinct load operation points (e.g. IoT, RoT) per sub-band group instead of the same operation level across the entire available band. The sub-band groups encompass the entire band. The facilitation system also comprises a variety of transmitting protocols, command increment variable stepsize methods and robust command response methods. The system thus provides more flexible reverse link resource management and more efficient utilization of the bandwidth.
    Type: Application
    Filed: January 12, 2015
    Publication date: May 14, 2015
    Inventors: Wanshi Chen, Xiaoxia Zhang, Durga Prasad Malladi, Xiliang Luo
  • Patent number: 9014114
    Abstract: Estimation of timing errors is disclosed that uses user equipment reference signals (UERSs). A UE models each channel in a user equipment reference signal (UERS) as a channel on an adjacent UERS tone multiplied by a phase ramping term. This phase ramping term is determined using an estimator on the modeled channels. The UE then determines the equivalent timing error by mapping the phase ramping terms into the estimated timing errors in the time domain. In coordinated multipoint (CoMP) systems, the UERS-based timing error may be used to identify an aligned common reference signal (CRS) associated with the network entity transmitting the data. With this determination, the UE may estimate a CRS-based timing error and either substitute the CRS-based timing error for the UERS-based timing error or calculate a further average timing error based on both the CRS-based and UERS-based timing errors.
    Type: Grant
    Filed: November 15, 2012
    Date of Patent: April 21, 2015
    Assignee: QUALCOMM Incorporated
    Inventors: Yi Huang, Tao Luo, Taesang Yoo, Xiliang Luo
  • Patent number: 9014287
    Abstract: A precoding scheme to accommodate user equipment (UEs) having higher Doppler speeds. In such transmission schemes, a different precoding matrix is applied to each orthogonal frequency division multiplex (OFDM) symbol in the transmission stream. Additionally, a downlink control message format is defined to handle assignment of multiple different transmission schemes using the same message format. The downlink control message format includes a control element in one of the message fields along with a set of parameters specifically applicable to the assigned transmission scheme. Based on the value of this control element, the UE sets the specific transmission scheme and determines a set of interpretation rules uniquely associated with that transmission scheme. Using the interpretation rules, the UE is able to read the set of parameters as applied to the selected transmission scheme.
    Type: Grant
    Filed: August 19, 2011
    Date of Patent: April 21, 2015
    Assignee: QUALCOMM Incorporated
    Inventors: Xiliang Luo, Peter Gaal, Hao Xu, Tao Luo, Kapil Bhattad, Juan Montojo, Wanshi Chen
  • Patent number: 8982743
    Abstract: Certain aspects of the present disclosure relate to techniques for indicating downlink assignments to a user equipment (UE). According to certain aspects, the techniques generally involve generating a downlink assignment index (DAI) indicating a number of assigned downlink transmissions for a user equipment (UE) configured to communicate using multiple component carriers and transmitting a physical downlink control channel (PDCCH) containing the DAI to the user equipment (UE) in a frequency division duplexing (FDD) subframe in which uplink and downlink transmissions may take place at the same time on different carrier frequencies.
    Type: Grant
    Filed: May 12, 2011
    Date of Patent: March 17, 2015
    Assignee: QUALCOMM Incorporated
    Inventors: Xiliang Luo, Wanshi Chen, Peter Gaal, Juan Montojo, Aleksandar Damnjanovic
  • Publication number: 20150071387
    Abstract: Certain aspects of the present disclosure relate to methods and apparatus for blind detection of cell-specific reference signals. Methods and apparatus are provided for detecting a cell-specific reference signal (CRS) in an orthogonal frequency division multiplexed (OFDM) symbol by a user equipment (UE). The method generally includes predicting a current channel response of a current OFDM symbol based on a channel response of at least one previous OFDM symbol, estimating a noise power level of the current OFDM symbol, forming a log likelihood ratio (LLR) of two detection hypotheses based on the predicted current channel response and the estimated noise power level, comparing the LLR to a pre-determined threshold, and determining that at least one CRS is present in the current OFDM symbol based on the comparison.
    Type: Application
    Filed: February 26, 2014
    Publication date: March 12, 2015
    Applicant: QUALCOMM INCORPORATED
    Inventors: Xiliang LUO, Wenshu ZHANG, Keith William SAINTS, Ke LIU, Kapil BHATTAD, Alexei Yurievitch GOROKHOV
  • Patent number: 8964703
    Abstract: A system and method for facilitating resource management in OFDM systems is provided. The system permits different and flexible resource cell metric operations levels (e.g. uplink load management, admission control, congestion control, signal handoff control) for different sub-bands. For the uplink load management, there are multiple distinct load operation points (e.g. IoT, RoT) per sub-band group instead of the same operation level across the entire available band. The sub-band groups encompass the entire band. The facilitation system also comprises a variety of transmitting protocols, command increment variable stepsize methods and robust command response methods. The system thus provides more flexible reverse link resource management and more efficient utilization of the bandwidth.
    Type: Grant
    Filed: November 1, 2007
    Date of Patent: February 24, 2015
    Assignee: QUALCOMM Incorporated
    Inventors: Wanshi Chen, Xiaoxia Zhang, Durga Prasad Malladi, Xiliang Luo
  • Publication number: 20150049672
    Abstract: Certain aspects relate to methods and apparatus for avoiding and/or escaping cell range expansion (CRE) in a heterogeneous network (HetNet). A user equipment (UE) may detect the occurrence of one or more conditions while the UE is in a region of cell range expansion (CRE) in which the UE may be handed over from a first cell of a first power class type to a second cell of a second power class type, the second power class type being lower than the first power class type. The UE may take action to stop being served by the second cell or avoid being handed over to the second cell in response to the detection.
    Type: Application
    Filed: August 13, 2014
    Publication date: February 19, 2015
    Inventors: Xiliang LUO, Brian Clarke BANISTER, Shivratna Giri SRINIVASAN, Keith William SAINTS, Amir AMINZADEH GOHARI, Wenshu ZHANG, Timothy Paul PALS, Ke LIU, Alexei Yurievitch GOROKHOV, Amir FARAJIDANA
  • Patent number: 8958393
    Abstract: Certain aspects of the present disclosure propose methods for enhanced handover procedures that are controlled by either the user equipment (UE) or the serving evolved node-B (eNB). The methods take into account the qualities of both the reverse and forward communication links between the UE and the neighboring eNBs in selecting a target eNB for handover.
    Type: Grant
    Filed: August 6, 2009
    Date of Patent: February 17, 2015
    Assignee: QUALCOMM Incorporated
    Inventors: Xiliang Luo, Juan Montojo
  • Patent number: 8942194
    Abstract: A user equipment (UE) is configured for carrier aggregation in a wireless communication system. The UE selects control information to be transmitted in an uplink control channel format in a component carrier of two or more component carriers, where the control information includes information types associated with different information reliability requirements. The UE generates an open-loop power control parameter and/or a closed-loop power control parameter based on the information types. The UE transmits the control information in the uplink control channel format at a power level determined by the open-loop power control parameter and/or the closed-loop power control parameter.
    Type: Grant
    Filed: May 18, 2011
    Date of Patent: January 27, 2015
    Assignee: QUALCOMM Incorporated
    Inventors: Wanshi Chen, Juan Montojo, Peter Gaal, Xiliang Luo, Aleksandar Damnjanovic
  • Patent number: 8923223
    Abstract: Techniques for sending control information in a wireless network are disclosed. A multi-carrier user equipment (UE) may receive a downlink grant on a physical downlink control channel (PDCCH) on a first component carrier (CC). The UE may also receive a data transmission associated with the PDCCH on a physical downlink shared channel (PDSCH) on a second CC. In some examples, the UE determines physical uplink control channel (PUCCH) resources for acknowledging the data transmission based on the first CC on which the PDCCH is received, the second CC on which the data transmission is received, and a transmission mode of the second CC. The UE may send acknowledgement/negative acknowledgement (ACK/NACK) information for the data transmission based on the PUCCH resources.
    Type: Grant
    Filed: August 10, 2011
    Date of Patent: December 30, 2014
    Assignee: QUALCOMM Incorporated
    Inventors: Wanshi Chen, Juan Montojo, Peter Gaal, Xiliang Luo
  • Patent number: 8891462
    Abstract: Certain aspects of the present disclosure provide techniques for determining resources for transmission of acknowledgement messages to a user equipment (UE). The techniques involve receiving a plurality of codewords from the UE via an uplink component carrier, and determining at least first and second index pairs identifying resources of a downlink channel to be used for transmitting acknowledgement messages for the received codewords. The first index pair is determined based on a first set of parameters, and the second index pair is determined based on the first set of parameters and a second set of one or more parameters. At least one of the parameters in the second set is a fixed value.
    Type: Grant
    Filed: May 12, 2011
    Date of Patent: November 18, 2014
    Assignee: QUALCOMM Incorporated
    Inventors: Xiliang Luo, Peter Gaal, Wanshi Chen, Tao Luo, Juan Montojo
  • Patent number: 8861408
    Abstract: Methods, systems, devices, and computer program products are described which facilitate the transmission and reception of acknowledgment/negative acknowledgment (ACK/NACK) feedback associated with downlink data transmissions in a multi-carrier wireless communication system. Scheduling request resources may be utilized to enable the transmission of ACK/NACK feedback for the multiple component carriers when a positive scheduling request is present and the techniques described may be utilized to improve the efficiency of control channel signaling in different system configurations.
    Type: Grant
    Filed: October 28, 2011
    Date of Patent: October 14, 2014
    Assignee: QUALCOMM Incorporated
    Inventors: Jelena M. Damnjanovic, Wanshi Chen, Xiliang Luo, Juan Montojo
  • Publication number: 20140295907
    Abstract: System(s) and method(s) are provided for inter-cell power control in the presence of fractional frequency reuse in a wireless communication system. Transmission power control of a terminal, and ensuing inter-cell interference mitigation, is accomplished by receiving load indicators from non-serving sectors, decoding those load indicators corresponding to the non-serving sectors that operate in the same frequency bands as the terminal, and adjusting the transmission power according the states of the decoded load indicators in conjunction with the associated non-serving sectors' forward link signal-to-interference-and-noise ratio at the terminal. The states of the load indicators reflect magnitudes of interference metrics with respect to threshold values. Load indicators can also be conveyed by the non-serving sector to a base station serving the terminal through a backhaul communication, and said base station can schedule an adjusted transmission power for the terminal.
    Type: Application
    Filed: June 11, 2014
    Publication date: October 2, 2014
    Inventors: Xiliang Luo, Durga Prasad Malladi, Xiaoxia Zhang
  • Patent number: 8848520
    Abstract: A method and apparatus for facilitating an aperiodic transmission of a sounding reference signal (SRS) are disclosed. Transmission resources are allocated to the aperiodic SRS transmission. A portion of a first downlink control message is modified to produce a second downlink control message, where the first downlink control message does not trigger an aperiodic SRS transmission. The second downlink message is transmitted.
    Type: Grant
    Filed: February 9, 2011
    Date of Patent: September 30, 2014
    Assignee: QUALCOMM Incorporated
    Inventors: Wanshi Chen, Peter Gaal, Juan Montojo, Tao Luo, Xiliang Luo
  • Patent number: 8830883
    Abstract: A method, apparatus, and computer program product for wireless communication are provided to receive a downlink grant including a transmission power control (TPC) command and a downlink assignment index (DAI) for an uplink subframe, determine that a value for at least one of the TPC commands is an ACK/NACK resource indicator for an uplink control channel resource based on a value of the DAI, and transmit one or more ACK/NACK bits using the uplink control channel resource. In another example, an eNB may be equipped to transmit a downlink grant including TPC command and DAI for an uplink subframe, wherein the DAI is greater than 1 and the TPC command is replaced with an ACK/NACK resource indicator, and receive a signal including uplink control channel information, where ACK/NACK feedback for one or more downlink subframes associated with the uplink subframe are included in a resource indicated by the resource indicator.
    Type: Grant
    Filed: November 14, 2011
    Date of Patent: September 9, 2014
    Assignee: QUALCOMM Incorporated
    Inventors: Wanshi Chen, Xiliang Luo, Juan Montojo
  • Patent number: 8817588
    Abstract: Methods, devices and computer program products are provided to improve uplink communications in a wireless communication system. Reference symbols in an uplink transmission radio subframe are time-frequency multiplexed with additional data symbols. The multiplexed data symbols are transmitted in an uplink transmission to another device within the wireless communication network along with non-multiplexed data symbols. The multiplexing operations enable the transmission of additional data symbols without increasing the overhead associated with the transmission of symbols in the radio subframe.
    Type: Grant
    Filed: October 21, 2010
    Date of Patent: August 26, 2014
    Assignee: QUALCOMM Incorporated
    Inventors: Xiliang Luo, Peter Gaal, Juan Montojo
  • Patent number: 8811371
    Abstract: Systems and methods are described herein for transmitting uplink SC-FDMA symbols. When an extended cyclic prefix is used, the symbols are divided into pairs, and the first symbol and a function of the second symbol in each pair is transmitted via a first antenna and the second symbol and a function of the first symbol in each pair is transmitted via a second symbol. When an unpaired symbol remains, the unpaired symbol is divided into halves, and a first function of the halves is transmitted on the first antenna and a second function of the halves is transmitted on the second antenna.
    Type: Grant
    Filed: September 22, 2009
    Date of Patent: August 19, 2014
    Assignee: QUALCOMM Incorporated
    Inventors: Peter Gaal, Juan Montojo, Xiliang Luo
  • Patent number: 8804639
    Abstract: A method of wireless communication includes receiving an upper layer configuration of multiple sets of ACK/NAK resources for uplink transmission. The receives resources correspond to at least one secondary downlink component carrier in a multicarrier configuration. The method also includes receiving a physical layer indicator of ACK/NAK resources in the sets.
    Type: Grant
    Filed: October 3, 2011
    Date of Patent: August 12, 2014
    Assignee: QUALCOMM Incorporated
    Inventors: Wanshi Chen, Peter Gaal, Xiliang Luo, Juan Montojo
  • Publication number: 20140211655
    Abstract: A method for communicating in an advanced long term evolution (LTE-A) network using common reference signal (CRS) resources associated with different interference levels due to resource partitioning is disclosed. Signals are received from an eNodeB indicating a subset of CRS resources for radio link monitoring (RLM) and/or reference signal received power (RSRP) measuring. The subset of CRS resources includes the CRS resources expected to have lower interference from the interfering eNodeBs. RLM and/or RSRP measurements are performed based on the indicated subset.
    Type: Application
    Filed: April 2, 2014
    Publication date: July 31, 2014
    Applicant: QUALCOMM Incorporated
    Inventors: Taesang Yoo, Tao Luo, Xiliang Luo
  • Patent number: 8780821
    Abstract: Techniques for performing channel interleaving to achieve similar SINRs for multiple code blocks are described. In one design, a transmitter station (e.g., a base station or a UE) determines a plurality of resource groups assigned for data transmission. Each resource group includes a plurality of resource elements formed by a cluster of subcarriers in a time interval. The transmitter station partitions a transport block into a plurality of code blocks, processes each code block to obtain data symbols for that code block, and maps the data symbols for each code block to at least one resource element in each of the plurality of resource groups. The transmitter station transmits the mapped data symbols for the plurality of code blocks to a receiver station. In one design, the transmitter station receives an ACK or a NACK for the transport block and retransmits all code blocks if a NACK is received.
    Type: Grant
    Filed: February 17, 2010
    Date of Patent: July 15, 2014
    Assignee: QUALCOMM Incorporated
    Inventors: Xiaoxia Zhang, Juan Montojo, Peter Gaal, Wanshi Chen, Xiliang Luo