Patents by Inventor Narayan Prasad

Narayan Prasad 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: 8897725
    Abstract: A method implemented in a wireless communications system is disclosed. The method includes: transmitting, from a wireless transmitter having a transmit antenna array, a first signal on each of a plurality of different transmit beams in transmitter (TX) sector level sweep (SLS), receiving, at a wireless receiver having a receive antenna array, the first signal, and determining, at the wireless receiver, quality of the first signal. Other methods, systems, and apparatuses also are disclosed.
    Type: Grant
    Filed: April 17, 2013
    Date of Patent: November 25, 2014
    Assignee: NEC Laboratories America, Inc.
    Inventors: Narayan Prasad, Kishore Ramachandran, Sampath Rangarajan
  • Publication number: 20140341064
    Abstract: A method implemented in a user equipment configured to be used in a multi-user (MU) multiple-input multiple-output (MIMO) wireless communications system is disclosed. The method includes transmitting to a base station a first channel state information (CSI) report determined according to a single-user (SU) MIMO rule, and transmitting to the base station a second CSI report determined according to an MU-MIMO rule. Other methods, apparatuses, and systems also are disclosed.
    Type: Application
    Filed: August 1, 2014
    Publication date: November 20, 2014
    Inventors: Narayan Prasad, Guosen Yue, Meilong Jiang, Mohammad A. Khojastepour, Sampath Rangarajan
  • Patent number: 8891677
    Abstract: A method includes obtaining a precoder for retransmission of one codeword responsive to known precoding matrix P of rank r and modulation and coding scheme MCS assignments used in an original transmission, and a desired retransmission rank r?; and scaling power in the retransmission responsive to at least two of 1) information parameters Index of UL precoder in previous transmission, 2) rank r of uplink UL precoder in previous transmission, 3) MCS assignments in previous retransmission (MCSi), 4) rank r? for UL retransmission 5) number of retransmit antennas used for codeword to be retransmitted x in previous transmission, 6) number of retransmit antennas x? used for retransmission, 7) precoder for UL retransmission, 8) UL precoders and channel information for previous transmission, and 8) latest channel measurements.
    Type: Grant
    Filed: November 9, 2011
    Date of Patent: November 18, 2014
    Assignee: NEC Laboratories America, Inc.
    Inventors: Guosen Yue, Narayan Prasad, Meilong Jiang, Sampath Rangarajan
  • Patent number: 8891391
    Abstract: A method to allocate resources in a wireless MIMO system, by enforcing per-cell orthogonality to avoid intra-cell interference; and allocating resources based on interference handling.
    Type: Grant
    Filed: April 27, 2012
    Date of Patent: November 18, 2014
    Assignee: NEC Laboratories America, Inc.
    Inventors: Narayan Prasad, Honghai Zhang, Luca Venturino, Jubin Jose, Sampath Rangarajan
  • Patent number: 8891529
    Abstract: A communications method implemented in a transmission point (TP) used in a coordinated multipoint transmission and reception (CoMP) system is disclosed. The communications method comprises transmitting, to a user equipment (UE), attributers for up to four indicators indicating at least physical downlink shared channel (PDSCH) resource element (RE) mapping, and transmitting, to the UE, one of the four indicators, each of which is conveyed in 2 bits, wherein the four indicators comprises ‘00’, ‘01’, ‘10’, and ‘11’ corresponding to a first set, a second set, a third set, and a fourth set of parameters, respectively. Other methods, apparatuses, and systems are also disclosed.
    Type: Grant
    Filed: July 23, 2013
    Date of Patent: November 18, 2014
    Assignee: NEC Laboratories America, Inc.
    Inventors: Guosen Yue, Narayan Prasad, Meilong Jiang, Sampath Rangarajan
  • Patent number: 8873441
    Abstract: A method for LTE or WiMAX scheduling includes collecting, by a basestation BS, channel feedback from multiple mobiles with downlink traffic. The channel feedback enables the BS to determine an achievable rate or block error probability if transmitting to a mobile with a given modulation and coding scheme MCS and multiple-input multiple-output MIMO mode. The method includes determining, by the BS, which of the mobiles is scheduled on each resource block RB and what the MCS and MIMO mode is selected for each scheduled mobile, and allocating bits on the set of the RBs assigned to each scheduled mobile.
    Type: Grant
    Filed: January 4, 2012
    Date of Patent: October 28, 2014
    Assignee: NEC Laboratories America, Inc.
    Inventors: Honghai Zhang, Narayan Prasad, Sampath Rangarajan
  • Publication number: 20140241450
    Abstract: A method implemented in a base station used in a wireless communications system is disclosed. The method comprises having 1-layer, 2-layer, 3-layer, and 4-layer codebooks for 4 transmit antenna (4TX) transmission, each codebook including a plurality of precoding matrices, precoding data with one of the plurality of precoding matrices, and transmitting, to a user equipment, the precoded data, wherein each of the 1-layer and 2-layer codebooks comprises a first codebook and a second codebook, and wherein each precoding matrix in the first codebook comprises a first index and a second index. Other apparatuses, systems, and methods also are disclosed.
    Type: Application
    Filed: March 11, 2014
    Publication date: August 28, 2014
    Applicant: NEC LABORATORIES AMERICA, INC.
    Inventors: Narayan Prasad, Guosen Yue, Mohammad Khojastepour, Sampath Rangarajan
  • Publication number: 20140241449
    Abstract: A method implemented in a base station used in a wireless communications system is disclosed. The method comprises having a codebook including a plurality of precoding matrices, precoding data with one of the plurality of precoding matrices, and transmitting, to a user equipment, the precoded data, wherein each precoding matrix W satisfies W=W(1)W(2), where first matrix W(1) is chosen from first codebook (1), and second matrix W(2) is chosen from a second codebook. Other apparatuses, systems, and methods also are disclosed.
    Type: Application
    Filed: March 6, 2014
    Publication date: August 28, 2014
    Applicant: NEC Laboratories America, Inc.
    Inventors: Narayan Prasad, Guosen Yue, Mohammad Khojastepour, Sampath Rangarajan
  • Publication number: 20140233414
    Abstract: A method for determining attributes of communication channels of multi-user (MU)-multiple input multiple output (MIMO) users in an orthogonal frequency division multiplexing based multiple access (OFDMA) system is disclosed. The method comprises receiving from a base station, for at least one sub-band of contiguous sub-carriers, an indication of an estimate of or an upper-bound on a total number of streams that are co-scheduled by the base station on the at least one sub-band or an indication of a fraction of a transmit power at the base station that is applied to streams that are scheduled for transmission to a particular user, determining one or more signal quality measures for the at least one sub-band based on at least one of the fraction or the estimate of or the upper-bound on the total number of streams that are scheduled by the base station on the at least one sub-band, and transmitting to the base station an indication of the one or more signal quality measures.
    Type: Application
    Filed: April 8, 2014
    Publication date: August 21, 2014
    Applicant: NEC Laboratories America, Inc.
    Inventors: Narayan Prasad, Guosen Yue, Mohammad A. Khojastepour, Meilong Jiang, Sampath Rangarajan
  • Publication number: 20140226745
    Abstract: A method implemented in a user equipment used in a multi-user multiple input multiple output (MU-MIMO) wireless communications system is disclosed. The method includes receiving from a base station an indication of a first modulation type for the user equipment, receiving a first data signal for the user equipment, receiving a second data signal for a co-scheduled user equipment, where a second modulation type for the co-scheduled user equipment is unknown to the user equipment, and deciding the second modulation type. Other methods, systems, and apparatuses also are disclosed.
    Type: Application
    Filed: April 22, 2014
    Publication date: August 14, 2014
    Applicant: NEC Laboratories America, Inc.
    Inventors: Narayan Prasad, Guosen Yue, Mohammad A. Khojastepour, Meilong Jiang, Sampath Rangarajan
  • Publication number: 20140223200
    Abstract: Aspects of charger detection and optimization prior to host control are described herein. In various embodiments, a condition of whether reverse current is present on a system bus is detected. When the condition for reverse current is present, reverse current is sunk by one or more of various reverse current sink circuits. By relying upon one or more of the reverse current sink circuits, for safety, to address or mitigate the condition for reverse current, a detector may be able to identify or distinguish among several different types of charger or charging ports coupled to a system bus allowing a charger to be selected optimally. Further, an indicator of the type of charger or charging port coupled to the system bus is communicated over a single pin interface, for backwards compatibility with circuits capable of identifying between only two different types of chargers.
    Type: Application
    Filed: July 25, 2013
    Publication date: August 7, 2014
    Inventors: Walid Nabhane, Mark D. Rutherford, Narayan Prasad Ramachandran, David Chang, Yi Ting Chen, Chenmin Zhang, Ajmal A. Godil
  • Publication number: 20140219379
    Abstract: A method implemented in a user terminal is disclosed. The method comprises obtaining known precoding matrix P of rank r and modulation and coding scheme assignments used in an original transmission, and a desired retransmission rank r?, forming an approximate channel covariance matrix, estimating a minimum mean square error receiver SINR for each layer to be retransmitted responsive to said forming, and finding a retransmission precoding matrix from a preceding codebook that maximizes a sum-rate for enabling precoding selections for retransmissions in uplink multiple-input multiple-output MIMO hybrid automatic repeat request HARQ. Other methods, apparatuses, and systems also are disclosed.
    Type: Application
    Filed: April 8, 2014
    Publication date: August 7, 2014
    Applicant: NEC Laboratories America, Inc.
    Inventors: Guosen Yue, Narayan Prasad, Meilong Jiang, Sampath Rangarajan
  • Patent number: 8798011
    Abstract: A method implemented in a user equipment configured to be used in a multi-user (MU) multiple-input multiple-output (MIMO) wireless communications system is disclosed. In an aspect, the user equipment transmits to a base station a first channel state information (CSI) report determined according to a single-user (SU) MIMO rule and a second CSI report determined according to an MU-MIMO rule.
    Type: Grant
    Filed: April 26, 2012
    Date of Patent: August 5, 2014
    Assignee: NEC Laboratories America, Inc.
    Inventors: Narayan Prasad, Guosen Yue, Meilong Jiang, Mohammad A. Khojastepour, Sampath Rangarajan
  • Publication number: 20140204865
    Abstract: A method for determining an optimal network utilization maximization in a communication system with wireless links in which current and coarse channel state information CSI is available from all users, along with a limited amount of fine CSI by way of a frame based entails a scheduling and feedback under which a virtual queue is associated with each user with virtual rates being determined at start of each frame and policy of each frame being determined by solving a decision process.
    Type: Application
    Filed: January 21, 2014
    Publication date: July 24, 2014
    Applicant: NEC Laboratories America , Inc.
    Inventors: Narayan Prasad, Sampath Rangarajan, Wenzhuo Ouyang
  • Publication number: 20140198750
    Abstract: A method implemented in a base station used in a mobile communications system is disclosed. The method includes configuring for a user equipment (UE) a channel state information (CSI) process for multi-user (MU) multiple-input and multiple-output (MIMO), the CSI process for MU-MIMO being associated with a channel part and an interference part, and according to the interference part, configuring the UE to measure or estimate inter-cell interference (ICI) and to compute or estimate intra-cell interference. Other apparatuses, systems, and methods also are disclosed.
    Type: Application
    Filed: January 15, 2014
    Publication date: July 17, 2014
    Applicant: NEC Laboratories America, Inc.
    Inventors: Narayan Prasad, Guosen Yue, Sampath Rangarajan
  • Publication number: 20140198751
    Abstract: A method implemented in a base station used in a wireless communications system where different antenna arrays are employed for transmissions to different co-scheduled users in a cell is disclosed. The method includes configuring multiple channel state information (CSI) processes for a user equipment (UE), and configuring, for the UE, a plurality of non-zero power (NZP) CSI reference signal (RS) resources, each of which is associated with an antenna array. Other apparatuses, systems, and methods also are disclosed.
    Type: Application
    Filed: January 15, 2014
    Publication date: July 17, 2014
    Applicant: NEC Laboratories America, Inc.
    Inventors: Narayan Prasad, Guosen Yue, Sampath Rangarajan
  • Patent number: 8767888
    Abstract: The present invention employs a look up table based implementation for the metric computations which eliminate redundancy and substantially reduce the number of multiplications. Moreover, inventive method exploits the fact that the un-normalized constellation symbols are complex integers so that the product of a real-number and an un-normalized constellation symbol can be implemented by only additions. The inventive method also enables a greater efficiency for whitening colored noise prior to demodulation, one of which involves no square-root operation. The invention results in less complexity, faster operation, lower power consumption, without sacrificing performance.
    Type: Grant
    Filed: March 29, 2012
    Date of Patent: July 1, 2014
    Assignee: NEC Laboratories America, Inc.
    Inventors: Narayan Prasad, Neda Cvijetic, Sampath Rangarajan, Ting Wang
  • Patent number: 8767665
    Abstract: A method implemented in a base station used in a wireless communications system is disclosed. The method comprises transmitting an index indicating data stream parameters, and transmitting an indication of the number of transmit antennas at the base station, wherein the data stream parameters for 8 transmit antennas are indicated by the index according to a first table, and wherein the data stream parameters for 4 transmit antennas are indicated by the index according to a second table. Other methods, apparatuses, and systems also are disclosed.
    Type: Grant
    Filed: August 15, 2013
    Date of Patent: July 1, 2014
    Assignee: NEC Laboratories America, Inc.
    Inventors: Mohammad A. Khojastepour, Narayan Prasad, Sampath Rangarajan
  • Patent number: 8761129
    Abstract: A method implemented in a user equipment configured to be used in a multi-user (MU) multiple-input multiple-output (MIMO) wireless communications system is disclosed. In an aspect, the user equipment transmits to a base station a first channel state information (CSI) report determined according to a single-user (SU) MIMO rule and a second CSI report based on a residual error.
    Type: Grant
    Filed: April 26, 2012
    Date of Patent: June 24, 2014
    Assignee: NEC Laboratories America, Inc.
    Inventors: Narayan Prasad, Guosen Yue, Meilong Jiang, Mohammad A. Khojastepour, Sampath Rangarajan
  • Patent number: 8750358
    Abstract: A method for improving multiple-input multiple-output MIMO downlink transmissions includes obtaining a channel state information CSI report including preferred matrix index PMI for precoding, channel quality index CQI and rank index RI at a base station from user terminals through a channel feedback; applying selectively a signal-to-interference-plus-noise-ratio SINR offset to a SINR of said CSI report; applying selectively a rate matching responsive to SINR offset or the CSI report; and controlling or adjusting the SINR offset.
    Type: Grant
    Filed: April 6, 2012
    Date of Patent: June 10, 2014
    Assignee: NEC Laboratories America, Inc.
    Inventors: Guosen Yue, Narayan Prasad, Meilong Jiang, Mohammad A. Khojastepour, Sampath Rangarajan