Patents by Inventor Sudhir Ramakrishna

Sudhir Ramakrishna 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: 9100897
    Abstract: A base station is provided. The base station includes a transmit path circuitry that generates a masking sequence to mask a cyclic redundancy check of a control channel information element. The masking sequence includes a 4-bit prefix. The three least significant bits of the 4-bit prefix indicate a message type of the control channel information element. A subscriber station is also provided. The subscriber station includes a receive path circuitry that determines a message type of a control channel information element using a three least significant bits of a 4-bit prefix of a masking sequence used to mask a cyclic redundancy check of the control channel information element.
    Type: Grant
    Filed: November 22, 2010
    Date of Patent: August 4, 2015
    Assignee: SAMSUNG ELECTRONICS CO., LTD.
    Inventors: Zhouyue Pi, Sudhir Ramakrishna, Kaushik Josiam
  • Publication number: 20150124738
    Abstract: A method and an apparatus for channel estimation. The method includes identifying a set of preferred BS receive beams for each of a plurality of BS antenna SAs based on periodic pilot transmissions from a UE transmitted using predefined UE transmit beams. The method also includes transmitting a request for the UE to transmit pilot signals for the set of preferred BS receive beams. The method further includes receiving the pilot signals using the set of preferred BS receive beams. The method also includes performing channel estimation and determining the data transmission parameters based on the received pilot signals, the data transmission parameters including at least one receive beam at each UE antenna SA to be used for data reception. Additionally, the method includes transmitting, to the UE, information for identifying the at least one receive beam at each UE antenna SA to be used for data reception.
    Type: Application
    Filed: August 29, 2014
    Publication date: May 7, 2015
    Inventors: Sudhir Ramakrishna, Jaspreet Singh
  • Patent number: 8989086
    Abstract: When a subscriber station (SS) encounters interference caused an interfering base station (BS), the interference can be mitigated regardless of whether the interfering base station is a CSG-Closed BS or whether the SS is connected to a serving BS. If the SS is not connected to a serving BS and cannot access the interfering BS, the SS will signal the interfering BS directly to request the interfering BS to perform IM. If the SS is a legal user, and conditions to initiate IM are met, the interfering BS will perform IM until conditions to terminate IM are met. If the SS is connected to a serving BS, the serving BS will request the interfering BS to perform or terminate interference mitigation (IM) on behalf of the SS if certain conditions are satisfied.
    Type: Grant
    Filed: November 11, 2010
    Date of Patent: March 24, 2015
    Inventors: Ying Li, Ji-Yun Seol, Young Bo Cho, Zhouyue Pi, Sudhir Ramakrishna, Kaushik Josiam, Jaehyuk Jang
  • Publication number: 20140334564
    Abstract: A method for providing low-complexity hybrid precoding is provided. The method includes identifying a subset of a plurality of precoding sets as a reduced search space. A search is performed over the reduced search space for a preferred precoding set. Identifying the reduced search space may include determining at least one parameter, such as received power, for each of a plurality of beam directions.
    Type: Application
    Filed: February 20, 2014
    Publication date: November 13, 2014
    Applicant: Samsung Electronics Co., Ltd
    Inventors: Jaspreet Singh, Sudhir Ramakrishna
  • Patent number: 8879532
    Abstract: A method and base station apparatus for transmitting pilot data in a wireless communication system, and a method and mobile station apparatus for receiving pilot data in a wireless communication system are provided. The method for transmitting pilot data in a wireless communication system includes determining a pilot pattern in at least one resource block for each of one or more pilot streams, and transmitting the one or more pilot streams based on the determined respective pilot pattern in the at least one resource block, wherein the at least one resource block comprises a plurality of subcarriers and a plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols.
    Type: Grant
    Filed: March 11, 2010
    Date of Patent: November 4, 2014
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Jiann-An Tsai, Zhouyue Pi, Kaushik Josiam, Farooq Khan, Sudhir Ramakrishna
  • Patent number: 8861528
    Abstract: A base station for use in a wireless network that communicates with mobile stations according to the IEEE 802.16m standard. The base station transmits unicast data and E-MBS data in the downlink to mobile stations using physical resource units (PRUs) that are partitioned into a plurality of frequency partitions. The base station transmits E-MBS data using a first set of PRUs in at least a first common frequency partition, wherein the first set of PRUs are also used by at least a second base station to transmit E-MBS data. The base station further transmits unicast data using a second set of PRUs, wherein the second set of PRUs are randomized with respect to PRUs used by the at least a second base station to transmit unicast data.
    Type: Grant
    Filed: August 2, 2010
    Date of Patent: October 14, 2014
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Kaushik Josiam, Qi Wu, Heewon Kang, Sudhir Ramakrishna, TaeYoung Kim
  • Patent number: 8843129
    Abstract: A subscriber station can efficiently determine an accessible base station by scanning a subset of base stations based on an optimized list received from a serving base station. The subscriber station includes a white list that contains information regarding a number of closed subscriber group (CSG) base stations to which the subscriber station is subscribed. The subscriber station can transmit a request message that includes one or more of: indication of whether the detected identifier of the femto base station is in the whitelist or not; and its location information. In response, the base station can send a message that includes the nearby femtocells and whether the femtocell is accessible or inaccessible to the subscriber station. The femto base station can be designed to be in transmission off mode when none of its subscribers is in its coverage.
    Type: Grant
    Filed: December 6, 2010
    Date of Patent: September 23, 2014
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Ying Li, Zhouyue Pi, Sudhir Ramakrishna, Baowei Ji
  • Publication number: 20140198696
    Abstract: A user equipment (UE) performs a method for supporting discontinuous receive (DRX) in a wireless network. The method includes waking up at a wake up time associated with a beginning of a DRX cycle, the DRX cycle comprising a plurality of subframes. The method also includes determining whether to perform receive beam training before a beginning of a time period for downlink communication. The method further includes receiving data during the time period for downlink communication.
    Type: Application
    Filed: October 4, 2013
    Publication date: July 17, 2014
    Applicant: Samsung Electronics Co., LTD
    Inventors: Ying Li, Rakesh Taori, Zhouyue Pi, Sudhir Ramakrishna
  • Patent number: 8767642
    Abstract: For use in a wireless network, a base station configured to communicate in the wireless network is provided. The base station includes a processor coupled to a transmitter and configured to generate a resource allocation message. The resource allocation message includes a plurality of fixed length fields, one or more primary variable-length fields, and a plurality of secondary variable-length fields. The one or more primary variable-length fields occupy a position in the resource allocation message preceding as many of the fixed length fields as permitted by rules that govern a structure of the resource allocation message. The one or more primary variable-length fields are positioned in the resource allocation message such that when the resource allocation message is partitioned and allocated across a sequence of basic units (BUs), every primary variable-length field appears in a smallest possible sequence of BUs starting from the first BU in the sequence.
    Type: Grant
    Filed: November 23, 2010
    Date of Patent: July 1, 2014
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Sudhir Ramakrishna
  • Patent number: 8625693
    Abstract: Methods for a transmitter station and a receiver station to perform beamforming in a wireless communication system, and a transmitter station and a receiver station to perform the corresponding method, are provided. The method for the transmitter station to perform beamforming in the wireless communication system includes estimating and tracking a long-term averaged and normalized channel correlation matrix between the transmitter station and a receiver station, determining beamforming coefficients based on the tracked long-term averaged and normalized channel correlation matrix, and communicating with the receiver station using the determined beamforming coefficients, wherein the receiver station also estimates and tracks the long term averaged and normalized channel correlation matrix, and determines beamforming coefficients based on the tracked long-term averaged and normalized channel correlation matrix.
    Type: Grant
    Filed: October 26, 2010
    Date of Patent: January 7, 2014
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Jiann-An Tsai, Zhouyue Pi, Sudhir Ramakrishna
  • Patent number: 8619688
    Abstract: A mobile station and base station are capable of communicating in a wireless network via a set of contiguous or non-contiguous sub-bands. The base station transmits a resource allocation to the mobile station. The resource allocation message includes a sub-band index (SBI) field, a number of messages field, a contiguous allocation indicator field, or a combination of these. Based on the SBI field, one or more of the number of messages field and contiguous allocation indicator field, the mobile station can identify the set of sub-bands allocated to it by the base station.
    Type: Grant
    Filed: March 23, 2010
    Date of Patent: December 31, 2013
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Sudhir Ramakrishna
  • Publication number: 20130315321
    Abstract: To reduce the duration of a cyclic prefix used for a multiple input, multiple output (MIMO) communications channel, delay spread variations for different transmit/receive beam pair combination is estimated and used for fast beam switching and to support single user MIMO (SU-MIMO) even when the CP difference between two beams is large. Beam switching reference signals are employed to estimate delay spread exceeding current CP, and to support beam switching. CP covering sub-clusters within clusters for the MIMO channel are exploited to reduce the CP requirement and improve efficiency. Any one of a number of different CP durations may be selected for each different mobile station, using one of a finite set of subframe configurations for which the CP durations of different symbol locations within the subframe are predefined. Dynamically switching subframe configurations by the system accommodates high mobility.
    Type: Application
    Filed: April 4, 2013
    Publication date: November 28, 2013
    Applicant: Samsung Electronics Co., Ltd.
    Inventors: Sridhar Rajagopal, Shadi Abu-Surra, Ankit Gupta, Sudhir Ramakrishna, Kaushik Josiam, Zhouyue Pi, Ying Li
  • Publication number: 20130250884
    Abstract: A resource allocation message includes a resource allocation field. The resource allocation field includes a first field that includes either a first sub-field or a first sub-field and a second sub-field with the first sub-field configured to hold a first value that indicates two or more logical indices and the second sub-field configured to hold a third value. Each of the logical indices is associated with a sub-band pair of resource units. The sub-band pair of resource units includes either a first sub-band resource unit or a first sub-band resource unit and a second sub-band resource unit. The resource allocation field also includes a second field configured to hold a second value that indicates, either alone or in combination with the third value, a first sub-band resource unit or a second sub-band resource unit for each of the sub-band pair of resource units indicated by the first field.
    Type: Application
    Filed: April 29, 2013
    Publication date: September 26, 2013
    Applicant: Samsung Electronics Co., Ltd.
    Inventor: Sudhir Ramakrishna
  • Publication number: 20130237218
    Abstract: A mobile station is configured to scan cells in a wireless network. The mobile station includes at least one antenna configured to transmit and receive wireless signals. The mobile station also includes a processor coupled to the at least one antenna, the processor configured to scan for one or more neighboring base station cells in a same frequency band as a serving base station cell using one or more receive beams. The one or more receive beams used for scanning are different than receive beams used for data communication with the serving base station cell.
    Type: Application
    Filed: February 8, 2013
    Publication date: September 12, 2013
    Applicant: Samsung Electronics Co., Ltd.
    Inventors: Ying Li, Zhouyue Pi, Sridhar Rajagopal, Pavan Nuggehalli, Shadi Abu-Surra, Sudhir Ramakrishna
  • Publication number: 20130051489
    Abstract: Channel time and frequency correlations are determined from OFDM symbols and subframes using appropriately scaled sums of the products of the received pilot symbols at predetermined intervals n in time and/or frequency of resource elements within the resource blocks of the subframes. The correlation estimates may optionally be improved using pilot symbols for a plurality of antennas and for a plurality of pilot signal ports, and across a plurality of subframes. The calculated channel time and frequency correlations may be employed to improve estimates of channel characteristics for purposes such as selection of a transmission mode between a base station and a user equipment on the channel or for the purpose of channel equalization and data demodulation.
    Type: Application
    Filed: August 28, 2012
    Publication date: February 28, 2013
    Applicant: Samsung Electronics Co., Ltd.
    Inventors: Jaspreet Singh, Sudhir Ramakrishna
  • Publication number: 20120178464
    Abstract: For use in a machine device, a method to support machine-to-machine communications over a network includes acquiring system information from the network. The method also includes determining a ranging channel during a ranging back-off window. The method further includes performing ranging based on the determined ranging channel. The method still further includes communicating over the network. The ranging channel is determined according to a ranging priority of the machine device.
    Type: Application
    Filed: January 5, 2012
    Publication date: July 12, 2012
    Applicant: Samsung Electronics Co., Ltd.
    Inventors: Ying Li, Kaushik Josiam, Sudhir Ramakrishna
  • Publication number: 20120015649
    Abstract: A subscriber station can efficiently determine an accessible base station by scanning a subset of base stations based on an optimized list received from a serving base station. The subscriber station includes a white list that contains information regarding a number of closed subscriber group (CSG) base stations to which the subscriber station is subscribed. The subscriber station can transmit a request message that includes one or more of: indication of whether the detected identifier of the femto base station is in the whitelist or not; and its location information. In response, the base station can send a message that includes the nearby femtocells and whether the femtocell is accessible or inaccessible to the subscriber station. The femto base station can be designed to be in transmission off mode when none of its subscribers is in its coverage.
    Type: Application
    Filed: December 6, 2010
    Publication date: January 19, 2012
    Applicant: Samsung Electronics Co., Ltd.
    Inventors: Ying Li, Zhouyue Pi, Sudhir Ramakrishna, Baowei Ji
  • Publication number: 20110170480
    Abstract: A base station is provided. The base station includes a transmit path circuitry that generates a masking sequence to mask a cyclic redundancy check of a control channel information element. The masking sequence includes a 4-bit prefix. The three least significant bits of the 4-bit prefix indicate a message type of the control channel information element. A subscriber station is also provided. The subscriber station includes a receive path circuitry that determines a message type of a control channel information element using a three least significant bits of a 4-bit prefix of a masking sequence used to mask a cyclic redundancy check of the control channel information element.
    Type: Application
    Filed: November 22, 2010
    Publication date: July 14, 2011
    Applicant: Samsung Electronics Co., Ltd.
    Inventors: Zhouyue Pi, Sudhir Ramakrishna, Kaushik Josiam
  • Publication number: 20110149891
    Abstract: For use in a wireless network, a base station configured to communicate in the wireless network is provided. The base station includes a processor coupled to a transmitter and configured to generate a resource allocation message. The resource allocation message includes a plurality of fixed length fields, one or more primary variable-length fields, and a plurality of secondary variable-length fields. The one or more primary variable-length fields occupy a position in the resource allocation message preceding as many of the fixed length fields as permitted by rules that govern a structure of the resource allocation message. The one or more primary variable-length fields are positioned in the resource allocation message such that when the resource allocation message is partitioned and allocated across a sequence of basic units (BUs), every primary variable-length field appears in a smallest possible sequence of BUs starting from the first BU in the sequence.
    Type: Application
    Filed: November 23, 2010
    Publication date: June 23, 2011
    Applicant: Samsung Electronics Co., Ltd.
    Inventor: Sudhir Ramakrishna
  • Publication number: 20110116480
    Abstract: When a subscriber station (SS) encounters interference caused an interfering base station (BS), the interference can be mitigated regardless of whether the interfering base station is a CSG-Closed BS or whether the SS is connected to a serving BS. If the SS is not connected to a serving BS and cannot access the interfering BS, the SS will signal the interfering BS directly to request the interfering BS to perform IM. If the SS is a legal user, and conditions to initiate IM are met, the interfering BS will perform IM until conditions to terminate IM are met. If the SS is connected to a serving BS, the serving BS will request the interfering BS to perform or terminate interference mitigation (IM) on behalf of the SS if certain conditions are satisfied.
    Type: Application
    Filed: November 11, 2010
    Publication date: May 19, 2011
    Applicant: Samsung Electronics Co., Ltd.
    Inventors: Ying Li, Ji-Yun Seol, Young Bo CHO, Zhouyue Pi, Sudhir Ramakrishna, Kaushik Josiam, Jaehyuk Jang