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: 10021684
    Abstract: A computer-implemented method is provided for downlink scheduling in a MU-MIMO telecommunication system. The method includes identifying for each of multiple virtual users which collectively form a ground set of virtual users, a respective transmit precoder and receive beamformer combination that maximizes a difference between two submodular set functions applied over the ground set of virtual users, from among a plurality of combinations formed from a respective one of a plurality of transmit precoders and a respective one of a plurality of receive beamformers. The method includes transmitting data from at least some multiple virtual users, based on a downlink transmission schedule determined from the respective transmit precoder and receive beamformer combination identified for the at least some multiple virtual users. The ground set is formed from respective combinations of multiple actual users and the plurality of receive beamformers.
    Type: Grant
    Filed: August 14, 2017
    Date of Patent: July 10, 2018
    Assignee: NEC Corporation
    Inventors: Narayan Prasad, Yasaman Ghasempour, Mohammad Khojastepour, Sampath Rangarajan
  • Publication number: 20180152922
    Abstract: A method implemented in a base station for conveying scheduling information in an orthogonal frequency division multiple access (OFDMA) multi-user (MU)-multiple input multiple output (MIMO) system is disclosed. The method includes transmitting to a first user equipment (UE) the scheduling information including first scheduling information of the first UE and at least a portion of second scheduling information of at least one second UE, wherein the scheduling information includes a resource block (RB) assigned to the first UE, the number of streams, and an indication of one or more dedicated reference symbol (RS) layers assigned to the first UE. Other methods, systems, and apparatuses also are disclosed.
    Type: Application
    Filed: January 31, 2018
    Publication date: May 31, 2018
    Inventors: Narayan PRASAD, Mohammad Ali Khojastepour, Meilong Jiang, Xiadong Wang, Sampath Rangarajan
  • Publication number: 20180138955
    Abstract: A method implemented in a base station used in a wireless communications system is disclosed. The method comprises receiving, from a user equipment, rank indication (RI), a first precoding matrix indicator (PMI), and a second PMI (codebook index i2), wherein values 0-15 are assigned to the second PMI IPMI2 for RI=1 and values 0-3 are assigned to the second PMI IPMI2 for each of RI=2, RI=3, and RI=4, and wherein codebook index i2 comprises IPMI2 for RI=1. Other methods, apparatuses, and systems also are disclosed.
    Type: Application
    Filed: November 15, 2017
    Publication date: May 17, 2018
    Inventors: Guosen YUE, Narayan PRASAD, Sampath RANGARAJAN
  • Publication number: 20180124780
    Abstract: In a wireless communications system including a first transmission point and a second transmission point, a wireless communications method implemented in the first transmission point supporting coordinated multi-point transmission and reception (CoMP) is disclosed. The wireless communications method comprises transmitting to the second transmission point one or more CoMP hypothesis sets, and transmitting to the second transmission point a benefit metric corresponding to each CoMP hypothesis set, wherein the benefit metric can be a negative value. Other methods, systems, and apparatuses also are disclosed.
    Type: Application
    Filed: December 29, 2017
    Publication date: May 3, 2018
    Inventors: Narayan Prasad, Mohammad Khojastepour, Mustafa Arslan, Karthikeyan Sundaresan, Sampath Rangarajan
  • Publication number: 20180084532
    Abstract: A computer-implemented method is provided for downlink scheduling in a MU-MIMO telecommunication system. The method includes identifying for each of multiple virtual users which collectively form a ground set of virtual users, a respective transmit precoder and receive beamformer combination that maximizes a difference between two submodular set functions applied over the ground set of virtual users, from among a plurality of combinations formed from a respective one of a plurality of transmit precoders and a respective one of a plurality of receive beamformers. The method includes transmitting data from at least some multiple virtual users, based on a downlink transmission schedule determined from the respective transmit precoder and receive beamformer combination identified for the at least some multiple virtual users. The ground set is formed from respective combinations of multiple actual users and the plurality of receive beamformers.
    Type: Application
    Filed: August 14, 2017
    Publication date: March 22, 2018
    Inventors: Narayan Prasad, Yasaman Ghasempour, Mohammad Khojastepour, Sampath Rangarajan
  • Publication number: 20180084600
    Abstract: A computer-implemented method for establishing communication links in a millimeter wave (mmWave) network by solving a linear integer packing problem is presented. The computer-implemented method includes determining active communication links between a plurality of transmitters and a plurality of receivers, setting each active communication link to have any arbitrary chosen weight or priority, and setting a minimum link quality threshold for each active communication link and subjecting each active communication link to constraints. Detected phantom constraints are mitigated by introducing new constraints with binary coefficients and by modifying one or more existing constraints by setting a number of coefficients within the existing constraints to zero.
    Type: Application
    Filed: August 16, 2017
    Publication date: March 22, 2018
    Inventors: Narayan Prasad, Mohammad Khojastepour, Sampath Rangarajan, Yasaman Ghasempour
  • Patent number: 9906340
    Abstract: A method and transmitting device are provided for coordinated multi-point transmission scheduling by a transmitting device over one or more heterogeneous wireless networks that include a set of clusters. Each of the clusters has a set of transmission points for serving a set of user equipment devices. The method includes determining constraints imposed on any of the user equipment devices. The method further includes receiving channel state information feedback from the user equipment devices. The method also includes obtaining user weights and buffer sizes. The method additionally includes iteratively determining a weighted sum of user rates based on the constraints, the channel state information feedback, the user weights, and the buffer sizes. The iteratively determining step determines the weighted sum of user rates based on an initial weighted sum of user rates determined for the user equipment devices without the constraints.
    Type: Grant
    Filed: February 4, 2016
    Date of Patent: February 27, 2018
    Assignee: NEC Corporation
    Inventors: Narayan Prasad, Sampath Rangarajan, Yasushi Maruta, Duong Pham, Arun Gurung, Caroline Liang, Patricia Wells, Robert Arnott
  • Patent number: 9888469
    Abstract: In a wireless communications system including a first transmission point and a second transmission point, a wireless communications method implemented in the first transmission point supporting coordinated multi-point transmission and reception (CoMP) is disclosed. The wireless communications method comprises transmitting to the second transmission point one or more CoMP hypothesis sets, and transmitting to the second transmission point a benefit metric corresponding to each CoMP hypothesis set, wherein the benefit metric can be a negative value. Other methods, systems, and apparatuses also are disclosed.
    Type: Grant
    Filed: March 18, 2015
    Date of Patent: February 6, 2018
    Assignee: NEC Corporation
    Inventors: Narayan Prasad, Mohammad Khojastepour, Mustafa Arslan, Karthikeyan Sundaresan, Sampath Rangarajan
  • Patent number: 9847818
    Abstract: A method implemented in a base station used in a wireless communications system is disclosed. The method comprises receiving, from a user equipment, rank indication (RI), a first precoding matrix indicator (PMI), and a second PMI (codebook index i2), wherein values 0-15 are assigned to the second PMI IPMI2 for RI=1 and values 0-3 are assigned to the second PMI IPMI2 for each of RI=2, RI=3, and RI=4, and wherein codebook index i2 comprises IPMI2 for RI=1. Other methods, apparatuses, and systems also are disclosed.
    Type: Grant
    Filed: June 4, 2014
    Date of Patent: December 19, 2017
    Assignee: NEC Corporation
    Inventors: Guosen Yue, Narayan Prasad, Sampath Rangarajan
  • Publication number: 20170324456
    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: July 26, 2017
    Publication date: November 9, 2017
    Applicant: NEC Corporation
    Inventors: Narayan PRASAD, Guosen YUE, Mohammad KHOJASTEPOUR, Sampath RANGARAJAN
  • Patent number: 9813922
    Abstract: A system and method for resource management in a heterogeneous wireless network wherein the resources of the mobile communications system are managed on a coarse time-scale and a fine time-scale. The coarse time-scale management comprises a first stage of determining the user association for each of the plurality of TPs followed by a second stage of determining activation fractions for all TPs. The determining of the user association is performed by utilizing a GLS procedure having a Greedy Stage and a Local Search Stage. In the Greedy Stage, new user, TP pairs are analyzed and the pair with the greatest improvement in system utility is selected. In the Local Search Stage, potential swaps are analyzed and a pair offering the greatest improvement that exceeds a threshold is selected. The determining of activation fractions for all TPs is performed by utilizing an auxiliary function method.
    Type: Grant
    Filed: July 29, 2015
    Date of Patent: November 7, 2017
    Assignee: NEC Corporation
    Inventors: Narayan Prasad, Vaibhav Singh, Sampath Rangarajan
  • Publication number: 20170318601
    Abstract: Methods and a system are provided for enhanced long-term evolution scheduling. A ranking is constructed for one or more users scheduled on one or more resource blocks. A layer mapping is generated, using a finite modulation and coding scheme, utilizing the ranking of each of the one or more users for the one or more resource blocks. An enhanced ranking is determined, using a finite constraint on a buffer for each of the one or more users, for the one or more resource blocks utilizing the layer mapping. The enhanced ranking is deployed into a schedule for the one or more resource blocks being utilized by each of the one or more users. Bandwidth usage is optimized in the one or more resource blocks by utilizing the schedule.
    Type: Application
    Filed: May 1, 2017
    Publication date: November 2, 2017
    Inventors: Narayan Prasad, Sampath Rangarajan, Patricia Wells, Robert Arnott
  • Publication number: 20170303296
    Abstract: A computer-implemented method for associating users to transmission points over an uplink (UL) of a heterogeneous network (HetNet) is presented. The computer-implemented method includes communicating, via the processor, with a cluster of transmission points, associating each user to one transmission point within the cluster of transmission points by a two-stage procedure, and performing sub-frame scheduling independently by each transmission point within the cluster of transmission points over a set of users associated with.
    Type: Application
    Filed: April 12, 2017
    Publication date: October 19, 2017
    Inventors: Narayan Prasad, Sampath Rangarajan, Caroline Liang
  • Patent number: 9755716
    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: Grant
    Filed: May 2, 2016
    Date of Patent: September 5, 2017
    Assignee: NEC Corporation
    Inventors: Narayan Prasad, Guosen Yue, Mohammad Khojastepour, Sampath Rangarajan
  • Patent number: 9722725
    Abstract: A system and method for resource management in a heterogeneous wireless network that is performed via distributed implementation wherein the resources of the mobile communications system are managed on a coarse time-scale and a fine time-scale. The coarse time-scale management comprises a first stage of determining the user association for each of the TPs followed by a second stage of determining activation fractions for all TPs. The determining of the user association is performed by utilizing a GLS procedure having a Greedy Stage and a Local Search Stage. In the Greedy Stage, new user, TP pairs are analyzed and the pair with the greatest improvement in system utility is selected. In the Local Search Stage, potential swaps are analyzed and a pair offering the greatest improvement that exceeds a threshold is selected. The determining of activation fractions for all TPs is performed by utilizing an auxiliary function method.
    Type: Grant
    Filed: August 28, 2015
    Date of Patent: August 1, 2017
    Assignee: NEC Corporation
    Inventors: Narayan Prasad, Vaibhav Singh, Sampath Rangarajan, Mustafa Arslan
  • Publication number: 20170111861
    Abstract: A method is provided for optimizing energy efficiency over an energy-harvesting Long Term Evolution cellular network. The method includes assigning (a) resource blocks, (b) transmission modes, and (c) bit loadings on the resource blocks to a set of users such that (i) the assigned resource blocks satisfy a system of linear ascending inequality constraints, and (ii) respective sums of the bit loadings for each of the users do not exceed respective queue sizes pertaining to the each of the users. The method further includes incorporating a resource block and transmission mode assignment for a user into downlink scheduler of a base station to cause the downlink scheduler to perform downlink scheduling in accordance with the resource block and transmission mode assignment.
    Type: Application
    Filed: September 20, 2016
    Publication date: April 20, 2017
    Inventors: Narayan Prasad, Sampath Rangarajan, Hajar Mahdavi-Doost
  • Publication number: 20170070956
    Abstract: A method is provided for performing downlink scheduling in Long Term Evolution-Advanced networks. The method includes assigning resource blocks and transmission modes to users such that (i) each of the users that is assigned at least one of the resource blocks is assigned only one transmission mode chosen from a finite set of transmission modes, (ii) a sum of normalized costs across all of the resource blocks that are assigned to the users is less than unity. The method further includes incorporating a resource block and transmission mode assignment for a user into downlink scheduler of a base station to cause the downlink scheduler to perform downlink scheduling in accordance with the resource block and transmission mode assignment.
    Type: Application
    Filed: September 2, 2016
    Publication date: March 9, 2017
    Inventors: Narayan Prasad, Sampath Rangarajan, Hajar Mahdavi-Doost
  • Patent number: 9538415
    Abstract: We show that for any given muting fraction, a more constrained version of the problem of interest can be optimally solved in an efficient manner. In addition, the obtained solution is also a near-optimal solution for the original problem (for the given muting ratio). This allows us provide an algorithm that offers a good solution to the original problem with a tractable complexity. We also derive a lower complexity greedy that offers good performance and a certain worst-case performance guarantee. Simulations over an example LTE HetNet topology reveal the superior performance of the proposed algorithms and underscore the benefits of jointly exploiting partial muting of the macro and load balancing.
    Type: Grant
    Filed: January 23, 2015
    Date of Patent: January 3, 2017
    Assignee: NEC Corporation
    Inventors: Narayan Prasad, Mustafa Arslan, Sampath Rangarajan
  • Patent number: 9532257
    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: Grant
    Filed: August 1, 2014
    Date of Patent: December 27, 2016
    Assignee: NEC Corporation
    Inventors: Narayan Prasad, Guosen Yue, Meilong Jiang, Mohammad A. Khojastepour, Sampath Rangarajan
  • Patent number: 9450657
    Abstract: A method and system are provided. The method includes providing transmit precoders for a multiple-input and multiple-output communication system having a plurality of transmit antennas. The plurality of transmit antennas are for forming, using precoding, a plurality of channels such that each of the plurality of channels are configurable to serve a respective one of a plurality of users. The providing step includes imposing a respective average transmit antenna power constraint on each of the plurality of transmit antennas. The providing step further includes determining a diagonal precoder responsive to applying column scaling to a downlink channel matrix having a plurality of rows and a plurality of columns. The providing step additionally includes generating, from the diagonal precoder, a weighted precoder in accordance with the respective average antenna power constraint by optimizing a weighted sum-rate obtained upon transmitting respective signals over the plurality of channels.
    Type: Grant
    Filed: August 21, 2014
    Date of Patent: September 20, 2016
    Assignee: NEC Corporation
    Inventors: Guosen Yue, Narayan Prasad, Sampath Rangarajan, Samet Oymak