公开(公告)号：US20150365143A1

公开(公告)日：2015-12-17

申请号：US14738268

申请日：2015-06-12

Applicant: NEC Laboratories America, Inc.

Inventor： Eugene Chai ,  Xiufeng Xie ,  Mohammad Khojastepour ,  Karthikeyan Sundaresan ,  Sampath Rangarajan

IPC: H04B7/04 ,  H04B17/309

CPC classification number: H04B17/309 ,  H04B7/0452 ,  H04B7/0617 ,  H04B17/104

Abstract: Methods and systems for beam forming, implemented in a base station used in a communication system, include measuring channel state information (CSI) for a number of active phased-array antennas less than a full number of phased-array antennas. Analog beam forming weights are determined using the measured CSI. An optimal digital precoder is determined from the analog beam forming weights. The analog beam forming weights and optimal digital precoder are applied to one phased-array antenna.

Abstract translation: 在用于通信系统的基站中实现的用于波束形成的方法和系统包括测量小于全数量相控阵列天线的多个有源相控阵天线的信道状态信息（CSI）。 使用测量的CSI确定模拟波束形成权重。 从模拟波束形成权重确定最优数字预编码器。 模拟波束形成权重和最佳数字预编码器应用于一个相控阵天线。

公开(公告)号：US20230361849A1

公开(公告)日：2023-11-09

申请号：US18311353

申请日：2023-05-03

Applicant: NEC Laboratories America, Inc.

Inventor： Mohammad Khojastepour ,  Nariman Torkzaban

IPC: H04B7/06 ,  H04B7/0426 ,  H04B7/0495

CPC classification number: H04B7/06958 ,  H04B7/0639 ,  H04B7/0447 ,  H04B7/0495

Abstract: Beamforming methods and systems include determining a tradeoff curve between scanning beamwidth and transmission beamwidth based on a channel distribution for a base station. A set of scanning beams is selected based on the tradeoff curve. Devices around the base station are scanned for using the set of scanning beams. A set of transmission beams is selected for communications with the devices based on information received during the scanning. The set of transmission beams are used for transmission with a beamforming transmitter.

公开(公告)号：US11441890B2

公开(公告)日：2022-09-13

申请号：US17026139

申请日：2020-09-18

Applicant: NEC Laboratories America, Inc.

Inventor： Mohammad Khojastepour ,  Sampath Rangarajan

IPC: G01B11/00 ,  G01B11/14 ,  G01S5/02

Abstract: Aspects of the present disclosure describe systems, methods and structures that perform linear-grammetry and calibration by simultaneous multilateration using only edge distance estimates via two-way ranging.

公开(公告)号：US20210376906A1

公开(公告)日：2021-12-02

申请号：US17331078

申请日：2021-05-26

Applicant: NEC Laboratories America, Inc.

Inventor： Mohammad Khojastepour ,  Shahram Shahsavari

IPC: H04B7/06 ,  H04W72/04 ,  H04B7/0408

Abstract: Methods for transmitting data include sending a first probing packet using a first scanning beam, selected from a set of scanning beams. Feedback about the first probing packet is determined. A second probing packet is sent using a second scanning beam, selected from the set of scanning beams based on the determined feedback about the first probing packet. Feedback about the second probing packet is determined. A data transmission beam is determined based on the set of scanning beams and the received feedback about the first probing packet and the second probing packet. Data is transmitted using an antenna that is configured according to the determined transmission beam.

公开(公告)号：US10997488B2

公开(公告)日：2021-05-04

申请号：US16825395

申请日：2020-03-20

Applicant: NEC Laboratories America, Inc.

Inventor： Mohammad Khojastepour

IPC: H04Q5/22 ,  G06K19/077 ,  G06K7/10 ,  H01Q1/22 ,  H04W4/35 ,  G06K19/067

Abstract: A product tagging system is provided. The product tagging system includes at least one RF backscatter transmitter configured to emit a Radio Frequency (RF) signal on a frequency. The product tagging system further includes a plurality of passive RF backscatter tags, each associated with a respective product and configured to reflect and frequency shift the RF signal to a respective different frequency. The product tagging system also includes at least one RF backscatter receiver configured to read the respective product on the respective different frequency by detecting a distributed ambient backscatter signal generated by a reflection and frequency shifting of the RF signal by a corresponding one of the plurality of passive RF backscatter tags.

公开(公告)号：US10943419B2

公开(公告)日：2021-03-09

申请号：US16689663

申请日：2019-11-20

Applicant: NEC Laboratories America, Inc.

Inventor： Mohammad Khojastepour ,  Mustafa Arslan ,  Sampath Rangarajan

IPC: G07C9/00 ,  G07C9/28 ,  H01Q1/12 ,  E06B11/02 ,  G06K7/10 ,  H04W4/80 ,  E06B11/08 ,  G07C9/15 ,  G07C9/27

Abstract: A walk-though gate (WTG) is presented. The WTG includes a WTG structure including a first wall and a second wall, the first and second walls defining a walk though pass way between an entrance and exit, at least one sensor located at the entrance and the exit of a cavity defined by the walk though pass way, at least one first antenna facing toward an inside region of the WTG structure, at least one second antenna facing away from the inside region of the WTG structure, an RFID reader connected to the at least one first and second antennas, and a judgement module to judge if an RFID tag is located inside or outside the walk though gate structure.

公开(公告)号：US10931352B2

公开(公告)日：2021-02-23

申请号：US16591070

申请日：2019-10-02

Applicant: NEC Laboratories America, Inc.

Inventor： Shahram Shahsavari ,  Mohammad Khojastepour

IPC: H04B7/06

Abstract: A method for establishing communication links in a millimeter wave network is presented. The method includes determining an active communication link between first and second devices, the first device transmitting probing packets to the second device, employing a beam search technique to locate narrow beams by triggering the first device to adjust its transmission pattern to cover a fraction of an angular uncertainty region (AUR) at a beginning of a time-slot, and adjusting transmission coefficients of the first device based on a response received from the second device such that if the second device receives a probing packet, the second device sends an acknowledgment packet to the first device and the first device updates the AUR such that the AUR is set to a probed angular interval, and if the second device does not receive the probing packet, the first device updates the AUR to a complementary part of the probed interval.

公开(公告)号：US10739452B2

公开(公告)日：2020-08-11

申请号：US15891906

申请日：2018-02-08

Applicant: NEC Laboratories America, Inc.

Inventor： Mohammad Khojastepour ,  Mustafa Arslan

IPC: G01S13/26 ,  G01S7/292 ,  G01S13/38 ,  G01S13/75 ,  G01S11/02 ,  G01S5/02 ,  G01S5/12 ,  G01S5/14 ,  G01S11/06 ,  G01S7/35 ,  G01S7/41 ,  G01S13/34 ,  G01S13/36 ,  G06K7/10 ,  G06K19/07

Abstract: A system, method, and computer program product are provided for estimating a distance to an object. The system includes a transmitter for transmitting RF signals from a location of an object. The system further includes measurement equipment, including a receiver, for receiving the transmitted RF signals as corresponding received RF signals and measuring a plurality of phase differences at different frequencies between the transmitted RF signals and the corresponding received RF signals. The system also includes a processor. The processor is configured to calculate corrected phases by resolving one or more ambiguities from the plurality of phase differences. The processor is further configured to obtain a characteristic curve using the corrected phases. The processor is also configured to provide an estimate of the distance based on the characteristic curve and the corrected phases.

公开(公告)号：US10582529B2

公开(公告)日：2020-03-03

申请号：US15915491

申请日：2018-03-08

Applicant: NEC Laboratories America, Inc.

Inventor： Karthikeyan Sundaresan ,  Eugene Chai ,  Mohammad Khojastepour ,  Sampath Rangarajan

IPC: H04J3/06 ,  H04W72/12 ,  H04W56/00 ,  H04W48/16 ,  H04W88/08 ,  H04W84/04

Abstract: A system is provided for speculative scheduling that includes a base station having a processor. The processor computes an overall schedule for a set of clients. The overall schedule is formed from a set of speculative schedules, is configured to maximize unlicensed spectrum usage, and is computed by (a) determining a speculative schedule for each resource block from a set of resource blocks in a given sub-frame based on statistics determined for the clients individually and jointly, and (b) selecting, for formation into the overall schedule, (i) a particular resource block and (ii) the speculative schedule for the particular resource block, that yield the maximum incremental utility relative to already determined speculative schedules for other resource blocks in the set, based on criteria including uplink access statistics. The processor executes the overall schedule responsive to a completion of the speculative schedule determination for each resource block in the given sub-frame.

公开(公告)号：US20200050807A1

公开(公告)日：2020-02-13

申请号：US16517941

申请日：2019-07-22

Applicant: NEC Laboratories America, Inc.

Inventor： Mohammad Khojastepour ,  Mustafa Arslan ,  Sampath Rangarajan

IPC: G06K7/10

Abstract: Systems and methods for sequential detection-based classifications of radio-frequency identification (RFID) tags in three-dimensional space are provided. The methods include modeling a response from RFID tags as a probabilistic macro-channel and interrogating an RFID tag by transmitting a series of packets. Each packet is a transmit symbol and a first series of packet is a transmitted codeword. The method includes receiving, from the RFID tag, a second series of packets that is a received codeword in response to the transmitted codeword and finding a jointly typical transmit and receive codeword across all classes of macro-channels. The method also includes declaring a class of the RFID tag based on a largest likelihood between the transmitted codeword and the received codeword.