Patents by Inventor Hang Jin

Hang Jin 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: 7924957
    Abstract: The present invention discloses a method for generating beamformed multiple-input-multiple-output (MIMO) channels. The method comprises receiving by a base station (BS) a first plurality of receiving signals transmitted from a first antenna on a mobile station (MS), receiving by the BS a second plurality of receiving signals transmitted from a second antenna on the MS, nulling out a first predetermined percentage of the second plurality of receiving signals to generate a third plurality of receiving signals, calculating a first beamforming weighting vector corresponding to the first antenna on the MS using the first and third pluralities of receiving signals and creating a first beamformed MIMO channel from the BS to the first antenna on the MS using the first beamforming weighting vector.
    Type: Grant
    Filed: October 16, 2007
    Date of Patent: April 12, 2011
    Assignee: Cisco Technology, Inc.
    Inventor: Hang Jin
  • Patent number: 7925268
    Abstract: Techniques are provided herein to optimize up-link transmission power from a wireless terminal to a base transceiver station in a multicarrier system. A pathloss between the wireless terminal and the base transceiver station is determined. A determination is made if the pathloss is less than or larger than a predetermined value. One or more sub-carriers are assigned to the wireless terminal based on whether the pathloss between the wireless terminal and the base transceiver station is less than or larger than the predetermined value. A power cap command signal is sent from the base transceiver station to the wireless terminal for limiting a maximum allowable power transmitted by the wireless terminal to a predetermined level based on proximity of the one or more sub-carriers to an edge of a frequency band used for up-link transmissions made by the wireless terminal.
    Type: Grant
    Filed: August 11, 2006
    Date of Patent: April 12, 2011
    Assignee: Cisco Technology, Inc.
    Inventors: Chris Sanders, Santhalingam Balasekar, Hang Jin, John Grabner, Tuyen Banh
  • Publication number: 20110045787
    Abstract: A calibration-less transmit beamforming apparatus and method are provided. In a wireless communication device that comprises a plurality of antennas, a gain block is provided in the front-end module associated with each antenna and the same gain block is used during transmit and receive operations. As a result, the transmit phase offset and receive phase offset for each antenna are made to be equal, thereby achieving conditions for transmit beamforming without the need for complex antenna calibration algorithms and hardware.
    Type: Application
    Filed: August 19, 2009
    Publication date: February 24, 2011
    Applicant: CISCO TECHNOLOGY, INC.
    Inventors: Hang Jin, John Grabner
  • Publication number: 20110045792
    Abstract: Techniques are provided herein to generate beamforming weight vectors for transmissions to be made from a first wireless communication device, e.g., a base station, to a second wireless communication device, e.g., a client device. The first device has a plurality of antennas and receives uplink transmissions from the second device, each uplink transmission comprising a group of frequency subcarriers. The first device computes channel information from the received uplink transmission and computes one or more trigonometric waveforms determined to approximate the channel information. One or more downlink beamforming weight vectors are computed at any given frequency subcarrier (thus in any frequency subband) by interpolation using the one or more trigonometric waveforms.
    Type: Application
    Filed: August 19, 2009
    Publication date: February 24, 2011
    Applicant: CISCO TECHNOLOGY, INC.
    Inventors: Yanxin Na, Hang Jin
  • Patent number: 7889131
    Abstract: An apparatus, logic and method are provided to improve beamformed space time code (STC) wireless communication. A first device comprising a plurality of antennas receives signals at the plurality of antennas transmitted from a first antenna of a second device. A testing spatial signature for a second antenna of the second device is computed based on the signals received at the plurality of antennas of the first device from the first antenna of the second device. Using the testing spatial signature and the signals received at the plurality of antennas of the first device from the first antenna of the second device, beamforming weights are computed to be applied to a space time code signal to be transmitted from the first device to the second device via the plurality of antennas of the first device.
    Type: Grant
    Filed: March 25, 2008
    Date of Patent: February 15, 2011
    Assignee: Cisco Technology, Inc.
    Inventors: Li Guo, Hang Jin
  • Patent number: 7884763
    Abstract: Techniques are provided for computing beamforming weight vectors useful for multiple-input multiple-output (MIMO) wireless transmission of multiple signals streams from a first device to a second device. The techniques involve computing a plurality of candidate beamforming weight vectors based on the one or more signals received at the plurality of antennas of the first device. A sequence of orthogonal/partially orthogonal beamforming weight vectors are computed from the plurality of candidate beamforming weight vectors. The sequence of orthogonal/partially orthogonal beamforming weight vectors are applied to multiple signal streams for simultaneous transmission to the second device via the plurality of antennas of the first device.
    Type: Grant
    Filed: June 30, 2008
    Date of Patent: February 8, 2011
    Assignee: Cisco Technology, Inc.
    Inventors: Yanxin Na, Hang Jin
  • Patent number: 7881720
    Abstract: A radio planning method and apparatus for determining the setting scheme of base stations in an indoor environment is provided. A radio signal propagation model is generated including a theoretical attenuation part and an environment affecting part. Through on-site measurements, a site radio signal propagation characteristics database is constructed combining the indoor radio signal propagation model and on-site measurement results. Based on the environment-dependent database, a radio signal map representing the radio signal distribution to be generated in the site in the case of placing any type of base station in any position is generated, using the indoor radio signal propagation model. By applying a signal-to-quality mapping, the distribution of a specific quality metric for any base station is obtained. Thus, by inputting different base station parameters, respective radio signal maps can be generated to optimize positioning of base stations.
    Type: Grant
    Filed: August 29, 2006
    Date of Patent: February 1, 2011
    Assignee: International Business Machines Corporation
    Inventors: Jian Huang, Song Song, Zhe Xiang, Hang Jin Zhang
  • Patent number: 7876863
    Abstract: A method for determining timing positions in a wireless communications system comprises creating a time-domain timing detection window from a preamble of a receiving signal, generating a first vector of correlations between sampling points in the time-domain timing detection window and sampling points of a known preamble, identifying a pivot position from the largest correlation value of the first vector and generating second vectors based on the pivot position, generating a third vector comprising the largest elements of the second vectors; generating a fourth vector comprising sums of elements in the second vectors, generating fifth and sixth vectors comprising a sum of subsets of the third and fourth vectors, respectively, calculating a seventh vector using the fifth and sixth vectors according to a predetermined equation, and selecting an index of one element from the fifth and seventh vectors to be the timing position according to a predetermined rule.
    Type: Grant
    Filed: February 21, 2007
    Date of Patent: January 25, 2011
    Assignee: Cisco Technology, Inc.
    Inventors: Yanxin Na, Hang Jin, Daniel Wee, Bror Peterson
  • Patent number: 7876715
    Abstract: Techniques are provided herein to combine the advantages of beamforming with the advantages of multiple-input multiple output (MIMO) technology in a frequency division duplex (FDD) communication system, even when the uplink and downlink frequency separation exceeds the coherent bandwidth of the over-the-air-channels. At a first wireless communication device having M plurality of antennas, a wireless transmission is received that is sent from a second wireless communication device having P plurality of antennas. The first device computes spatial components associated with the transmission received at the M plurality of antennas. The first device selects the N strongest spatial components among the computed spatial components. The first device computes N beamforming weight vectors based on the N strongest spatial components. The first device then computes N MIMO beamforming weight vectors based on the N beamforming weight vectors.
    Type: Grant
    Filed: September 5, 2008
    Date of Patent: January 25, 2011
    Assignee: Cisco Technology, Inc.
    Inventors: Hang Jin, Yanxin Na, Li Guo, John Grabner
  • Publication number: 20110013711
    Abstract: Techniques are provided for computing downlink beamforming weights based on the received data at a base station from a mobile station in a MIMO communication system. An uplink transmission is received at a plurality of antennas at a first communication device from a second communication device, where the uplink transmission comprises a plurality of uplink subbands. The uplink spatial signature is estimated for each of the plurality of uplink subbands. The uplink spatial signature is decomposed into a plurality of direction of arrival (DOA) components for each uplink subband using a transform. Data representing multiple propagation paths between the first communication device and the second communication device is computed for each DOA component. A plurality of direction of departure (DOD) components for each of a plurality of downlink subbands is computed based on the data representing the multiple propagation paths.
    Type: Application
    Filed: July 14, 2009
    Publication date: January 20, 2011
    Applicant: CISCO TECHNOLOGY, INC.
    Inventors: Genyuan Wang, Li Guo, Ahmadreza Hedayat, Hang Jin
  • Publication number: 20110013708
    Abstract: Energy in a frequency band is received at a wireless communication device and data is generated representing samples of a received time domain waveform from the received energy. Data for groups of samples of the received time domain waveform is processed to transform the data for the received time domain waveform to produce data for an intermediate domain signal that is in neither the time domain nor the frequency domain. The data representing the intermediate domain signal is analyzed to determine whether a sequence having a predetermined pattern from a set of possible sequences is present in the received energy, and ultimately to determine a sequence of the predetermined pattern whose presence is detected in the received energy.
    Type: Application
    Filed: July 15, 2009
    Publication date: January 20, 2011
    Applicant: Cisco Technology, Inc.
    Inventors: Ahmadreza Hedayat, Mohammad Janani, Hang Jin
  • Publication number: 20110012787
    Abstract: Techniques are provided to improve receive beamforming at a wireless communication device that receives energy in a frequency band at M plurality of antennas, where the received energy includes desired signals and interference signals. The wireless communication device has no knowledge of the spatial signatures of the desired signals and interference signals. A weighted sum signal vector is computed from the received signals and a covariance matrix is computed from the receive signals. Eigenvalue decomposition of the covariance matrix is computed to obtain M eigenvalues of corresponding M eigenvectors of the covariance matrix. A correlation rate is computed between the M eigenvectors and the weighted sum signal vector. A combined receive beamforming and nulling weight vector is computed from the M eigenvectors and the weighted sum signal vector and based further on the correlation rate.
    Type: Application
    Filed: July 15, 2009
    Publication date: January 20, 2011
    Applicant: CISCO TECHNOLOGY, INC.
    Inventors: Yanxin Na, Hang Jin
  • Patent number: 7861137
    Abstract: A system for detecting one or more localized burst errors in a receiving message comprised of a plurality of codewords. The system comprises a trellis code decoder for decoding a receiving message with a plurality of codewords and calculating one or more cumulative metrics of a maximum likelihood path and one or more alternative paths from the receiving message, an error detection code (EDC) decoder for detecting existence of one or more errors in the decoded receiving message received from the trellis decoder, and a localized burst error detector activated by the EDC decoder upon detecting the existence of one or more errors in the decoded receiving message to identify at least one corrupted codeword among the plurality of codewords using the one or more cumulative metrics of a maximum likelihood path and the one or more alternative paths, wherein the system requests the re-transmission of the corrupted codeword.
    Type: Grant
    Filed: August 28, 2008
    Date of Patent: December 28, 2010
    Assignee: Cisco Technology, Inc.
    Inventors: Hanqing Lou, Ahmadreza Hedayat, Hang Jin
  • Publication number: 20100321237
    Abstract: Techniques are provided herein to detect ranging codes in energy received at a plurality of antennas of a wireless communication device. Energy is received at a plurality of antennas of a first wireless communication device and received signals are generated from the received energy. The received energy comprises a ranging transmission from one or more second wireless communication devices, wherein each ranging transmission comprises a ranging code selected from a set of possible ranging codes. A ranging code specific receive beamforming weight vector is generated for a ranging code in the set of possible ranging codes from the received signals. The ranging code specific receive beamforming weight vector is applied to corresponding ranging code specific signals derived from the received signals to produce ranging code specific beamformed signals. The ranging code specific beamformed signals are correlated to produce correlation results.
    Type: Application
    Filed: June 23, 2009
    Publication date: December 23, 2010
    Applicant: CISCO TECHNOLOGY, INC.
    Inventors: Yanxin Na, Genyuan Wang, Hang Jin
  • Patent number: 7839817
    Abstract: An apparatus for detecting uplink ranging codes includes a first transform unit for transforming data received from a mobile station to generate first outputs; a cross-correlation unit for comparing the first outputs with possible ranging codes to generate second outputs; a screening unit for selectively passing the second outputs representing parts of the received data that match the possible ranging codes; a second transform unit for transforming the second outputs from the screening unit to generate third outputs; and a detection unit for detecting the ranging codes for the received data based on the third outputs.
    Type: Grant
    Filed: February 26, 2007
    Date of Patent: November 23, 2010
    Assignee: Cisco Technology, Inc.
    Inventors: Genyuan Wang, Hang Jin, Mansoor Ahmed, Daniel Wee
  • Publication number: 20100279616
    Abstract: A wireless base station apparatus is provided that is configured to automatically optimize the radiation pattern it uses when installed for operation in a wireless network in order to serve wireless client devices within a coverage area. The wireless base station is configured to determine its geographical location and to evaluate its geographical location based on stored geographical map data that indicates the physical geographical environment surrounding its geographical location. Based on the physical geographical environment surrounding the geographical location, the base station determines a radiation pattern best suited to serve wireless client devices within a coverage area.
    Type: Application
    Filed: April 30, 2009
    Publication date: November 4, 2010
    Applicant: CISCO TECHNOLOGY, INC.
    Inventors: Hang Jin, John Grabner
  • Patent number: 7825856
    Abstract: Techniques are provided to compute beamforming weights at a communication device, e.g., a first communication device, based on transmissions received at a plurality of antennas from another communication device, e.g., a second communication device. A plurality of transmissions are received at the plurality of antennas of the first communication device from the second communication device. A covariance matrix associated with reception of a plurality of transmissions at the plurality of antennas of the first communication device is computed. Corresponding elements (e.g., all the rows or all the columns) of the covariance matrix are combined to produce a weighted channel signature vector. A receive beamforming weight vector is computed from the weighted channel signature vector.
    Type: Grant
    Filed: August 1, 2008
    Date of Patent: November 2, 2010
    Assignee: Cisco Technology, Inc.
    Inventors: Yanxin Na, Hang Jin
  • Patent number: 7822442
    Abstract: A system and method are provided for configuring an antenna array having a predetermined number of antennas. After providing an antenna correlation matrix for all antennas with regard to a mobile terminal, the antenna array is virtually partitioned into two or more sub-arrays based on the antenna correlation matrix such that correlations among antennas within each sub-array are higher than correlations among antennas belonging to different sub-arrays. One or more beamforming weights are generated corresponding to each antenna within the sub-arrays for applying to one or more signals transmitted therefrom, and at least one predetermined multiple-input-multiple-output (MIMO) mechanism is further applied among the sub-arrays by treating each sub-array as a virtual antenna.
    Type: Grant
    Filed: May 30, 2008
    Date of Patent: October 26, 2010
    Assignee: Cisco Technology, Inc.
    Inventors: Hang Jin, John Grabner
  • Patent number: 7817088
    Abstract: Techniques are provided for improving hybrid automatic repeat request retransmissions techniques in a beamformed multiple-input multiple-output wireless communication environment. At a first device comprising a first plurality of antennas, a plurality of beamforming weight vectors are applied to a corresponding plurality of signal streams for simultaneous transmission to a second device having a plurality of antennas. A determination is made whether the plurality of signal streams need to be retransmitted from the first device to the second device. When a retransmission needs to be made, an order in which the plurality of beamforming weight vectors are applied to the plurality of signal streams is switched for a retransmission attempt of the plurality of signal streams from the first device to the second device.
    Type: Grant
    Filed: October 10, 2008
    Date of Patent: October 19, 2010
    Assignee: Cisco Technology, Inc.
    Inventors: Hanqing Lou, Hang Jin
  • Publication number: 20100246720
    Abstract: Techniques are provided to determine channel variation of a wireless channel between a first wireless communication device and a second wireless communication device. The first wireless communication device receives a wireless transmission sent by the second wireless communication device. Received data is recovered from the wireless transmission received at the first wireless communication device. The received data is processed with each of multiple channel variation compensations to produce corresponding processed received data subjected to respective ones of the multiple channel variation compensations. For symbols in the received data and in each of the processed received data, distances are computed to their closest symbols in a symbol constellation set used by the second wireless communication device in the wireless transmission. A corresponding distance metric is computed from the distances for symbols in the received data and from the distances for symbols in each of the processed received data.
    Type: Application
    Filed: March 25, 2009
    Publication date: September 30, 2010
    Applicant: Cisco Technology, Inc.
    Inventors: Genyuan Wang, Hang Jin