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    Preambles in OFDMA System
    121.
    发明申请
    Preambles in OFDMA System 审中-公开

    公开(公告)号：US20190173722A1

    公开(公告)日：2019-06-06

    申请号：US16249672

    申请日：2019-01-16

    Applicant: APPLE INC.

    Inventor： Jianglei Ma ,  Hang Zhang ,  Wen Tong ,  Ming Jia ,  Peiying Zhu ,  Mo-Han Fong

    IPC: H04L27/26 ,  H04L5/00 ,  H04B7/0452 ,  H04B7/02 ,  H04L7/04 ,  H04W24/02

    Abstract: The present invention provides a preamble that is inserted into an OFDMA frame and has a common sequence for all the base stations participating in a transmission. The subscriber station performs fine synchronization using the common sequence on the common preamble, and the resulting peaks will provide the locations of candidate base stations. The base station specific search is then performed in the vicinities of those peaks by using base station specific pseudo-noise sequences. With this two stage cell search, the searching window is drastically reduced. The preamble is matched to known values by a respective receiver to decode the signals and permit multiple signals to be transferred from the transmitter to the receiver. The preamble may comprise two parts, Preamble-I and Preamble-2, which may be used in different systems, including multioutput, multi-input (MIMO) systems.

    Methods and systems for OFDM using code division multiplexing
    122.
    发明授权
    Methods and systems for OFDM using code division multiplexing 有权

    公开(公告)号：US10284322B2

    公开(公告)日：2019-05-07

    申请号：US16031047

    申请日：2018-07-10

    Applicant: Apple Inc.

    Inventor： Jianglei Ma ,  Ming Jia ,  Wen Tong ,  Peiying Zhu ,  Hua Xu ,  Hang Zhang ,  Mo-Han Fong

    IPC: H04L5/00 ,  H04B1/707 ,  H04L27/26 ,  H04W72/04 ,  H04B7/0404 ,  H04J13/00 ,  H04L25/02 ,  H04B7/06 ,  H04J13/16 ,  H04L25/03

    Abstract: In some embodiments of the invention, OFDM symbols are transmitted as a plurality of clusters. A cluster includes a plurality of OFDM sub-carriers in frequency, over a plurality of OFDM symbol durations in time. Each cluster includes data as well as pilot information as a reference signal for channel estimation. In some embodiments, a plurality of clusters collectively occupy the available sub-carrier set in the frequency domain that is used for transmission. In some embodiments of the invention data and/or pilots are spread within each cluster using code division multiplexing (CDM). In some embodiments pilots and data are separated by distributing data on a particular number of the plurality of OFDM symbol durations and pilots on a remainder of the OFDM symbol durations. CDM spreading can be performed in time and/or frequency directions.

    Pilot symbol patterns for transmission through a plurality of antennas
    123.
    发明授权
    Pilot symbol patterns for transmission through a plurality of antennas 有权

    公开(公告)号：US10200226B2

    公开(公告)日：2019-02-05

    申请号：US16110205

    申请日：2018-08-23

    Applicant: Apple Inc.

    Inventor： Jianglei Ma ,  Ming Jia ,  Wen Tong ,  Peiying Zhu ,  Hang Zhang ,  Hua Xu ,  Dongsheng Yu

    IPC: H04L27/26 ,  H04L25/02 ,  H04B7/06 ,  H04B7/08 ,  H04L5/00

    Abstract: A method and apparatus for improving channel estimation within an OFDM communication system. Channel estimation in OFDM is usually performed with the aid of pilot symbols. The pilot symbols are typically spaced in time and frequency. The set of frequencies and times at which pilot symbols are inserted is referred to as a pilot pattern. In some cases, the pilot pattern is a diagonal-shaped lattice, either regular or irregular. The method first interpolates in the direction of larger coherence (time or frequency). Using these measurements, the density of pilot symbols in the direction of faster change will be increased thereby improving channel estimation without increasing overhead. As such, the results of the first interpolating step can then be used to assist the interpolation in the dimension of smaller coherence (time or frequency).

    Pilot scheme for a MIMO communication system
    124.
    发明授权
    Pilot scheme for a MIMO communication system 有权

    公开(公告)号：US10110285B2

    公开(公告)日：2018-10-23

    申请号：US15691877

    申请日：2017-08-31

    Applicant: Apple Inc.

    Inventor： Jianglei Ma ,  Ming Jia ,  Hua Xu ,  Wen Tong ,  Peiying Zhu ,  Moussa Abdi

    IPC: H04W4/00 ,  H04B7/0452 ,  H04L5/00 ,  H04W72/04 ,  H04L27/26 ,  H04J13/18 ,  H04B7/0413 ,  H04W88/08 ,  H04L25/02 ,  H04J13/16 ,  H04L1/06

    Abstract: The present invention employs a pilot scheme for frequency division multiple access (FDM) communication systems, such as single carrier FDM communication systems. A given transmit time interval will include numerous traffic symbols and two or more short pilot symbols, which are spaced apart from one another by at least one traffic symbol and will have a Fourier transform length that is less than the Fourier transform length of any given traffic symbol. Multiple transmitters will generate pilot information and modulate the pilot information onto sub-carriers of the short pilot symbols in an orthogonal manner. Each transmitter may use different sub-carriers within the time and frequency domain, which is encompassed by the short pilot symbols within the transmit time interval. Alternatively, each transmitter may uniquely encode the pilot information using a unique code division multiplexed code and modulate the encoded pilot information onto common sub-carriers of the short pilot symbols.

    Methods and systems for OFDM using code division multiplexing
    127.
    发明授权
    Methods and systems for OFDM using code division multiplexing 有权

    公开(公告)号：US10044460B2

    公开(公告)日：2018-08-07

    申请号：US15399028

    申请日：2017-01-05

    Applicant: Apple Inc.

    Inventor： Jianglei Ma ,  Ming Jia ,  Wen Tong ,  Peiying Zhu ,  Hua Xu ,  Hang Zhang ,  Mo-Han Fong

    IPC: H04B1/00 ,  H04J13/00 ,  H04B1/707 ,  H04L5/00

    Abstract: In some embodiments of the invention, OFDM symbols are transmitted as a plurality of clusters. A cluster includes a plurality of OFDM sub-carriers in frequency, over a plurality of OFDM symbol durations in time. Each cluster includes data as well as pilot information as a reference signal for channel estimation. In some embodiments, a plurality of clusters collectively occupy the available sub-carrier set in the frequency domain that is used for transmission. In some embodiments of the invention data and/or pilots are spread within each cluster using code division multiplexing (CDM). In some embodiments pilots and data are separated by distributing data on a particular number of the plurality of OFDM symbol durations and pilots on a remainder of the OFDM symbol durations. CDM spreading can be performed in time and/or frequency directions.

    Method and system for combining DFT-transformed OFDM and non-transformed OFDM
    129.
    发明授权
    Method and system for combining DFT-transformed OFDM and non-transformed OFDM 有权

    公开(公告)号：US09825793B2

    公开(公告)日：2017-11-21

    申请号：US15195083

    申请日：2016-06-28

    Applicant: Apple Inc.

    Inventor： Jianglei Ma ,  Wen Tong ,  Ming Jia ,  Hua Xu ,  Peiying Zhu ,  Hang Zhang

    IPC: H04L27/26 ,  H04L1/00 ,  H04L5/00

    Abstract: Methods and systems are provided that enable an OFDM transmitter to be used for transmitting conventional OFDM or a form of transformed OFDM. A technique is provided for transforming a coded and modulated sequence of samples prior to an IFFT that enables the transformed sequence of samples to be transmitted using conventional OFDM or transformed OFDM. The selection of a transform function for transforming the coded and modulated sequence of samples may be based on optimizing the transform function for particular operating conditions between the transmitter and receiver. In some embodiments of the invention OFDM and time transformed OFDM are multiplexed in time and/or frequency in a transmission frame. In some embodiments of the invention a pilot pattern is provided in which the pilot are sent using OFDM and data is sent using OFDM and/or transformed OFDM.

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