System and Method for Mapping Symbols for MIMO Transmission
    41.
    发明申请
    System and Method for Mapping Symbols for MIMO Transmission 有权
    用于映射MIMO传输符号的系统和方法

    公开(公告)号:US20140072076A1

    公开(公告)日:2014-03-13

    申请号:US14077511

    申请日:2013-11-12

    Applicant: Apple Inc.

    Abstract: Methods and devices are provided for MIMO OFDM transmitter and receivers having odd and/even numbers of transmit antennas. Various methods for pre-coding information bits before space time coding (STC) are described for enabling transmission of information bits over all antennas. Methods of decoding received signals that have been pre-coded and STC coded are also provided by embodiments of the invention. Pilot patterns for downlink and uplink transmission between a base station and one or more wireless terminals for three transmit antenna transmitters are also provided. Variable rate codes are provided that combine various fixed rate codes in a manner that results in codes whose rates are dependent on all the various fixed rate codes that are combined

    Abstract translation: 为具有奇数和偶数个发射天线的MIMO OFDM发射机和接收机提供了方法和设备。 描述了用于在空间时间编码(STC)之前预编码信息比特的各种方法,以使得能够在所有天线上传输信息比特。 对已经被预编码和STC编码的接收信号进行解码的方法也由本发明的实施例提供。 还提供了用于三个发射天线发射机的基站与一个或多个无线终端之间的下行链路和上行链路传输的导频模式。 提供了可变速率代码,其以使得其速率取决于组合的所有各种固定速率代码的代码的方式组合各种固定速率代码

    Method and Systems for OFDM Using Code Division Multiplexing
    42.
    发明申请
    Method and Systems for OFDM Using Code Division Multiplexing 有权
    使用码分复用的OFDM方法和系统

    公开(公告)号:US20140064243A1

    公开(公告)日:2014-03-06

    申请号:US14079131

    申请日:2013-11-13

    Applicant: Apple Inc.

    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.

    Abstract translation: 在本发明的一些实施例中,OFDM符号作为多个簇发送。 在多个OFDM符号持续时间内,群集包括频率上的多个OFDM子载波。 每个簇包括数据以及作为信道估计的参考信号的导频信息。 在一些实施例中,多个集群共同地占用用于传输的频域中的可用子载波集合。 在本发明的一些实施例中,使用码分多路复用(CDM)在每个簇内扩展数据和/或导频。 在一些实施例中,通过在OFDM码元持续时间的其余部分上分配关于多个OFDM符号持续时间的特定数目和导频上的数据来分离导频和数据。 可以在时间和/或频率方向上执行CDM扩展。

    Preambles in OFDMA System
    45.
    发明申请
    Preambles in OFDMA System 有权
    OFDMA系统中的前言

    公开(公告)号:US20130077469A1

    公开(公告)日:2013-03-28

    申请号:US13680209

    申请日:2012-11-19

    Applicant: APPLE INC.

    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.

    Abstract translation: 本发明提供插入到OFDMA帧中并具有参与传输的所有基站的公共序列的前同步码。 用户站使用公共前导码上的公共序列执行精细同步,并且所得到的峰值将提供候选基站的位置。 然后通过使用基站专用伪噪声序列,在那些峰附近执行基站专用搜索。 通过这两个阶段的单元格搜索,搜索窗口大大减少。 前导码由相应的接收机与已知值匹配以对信号进行解码,并允许多个信号从发射机传送到接收机。 前导码可以包括两个部分,即前导码1和前导码2,其可以在不同的系统中使用,包括多输入多输入(MIMO)系统。

    Method and System for Combining DFT-Transformed OFDM and Non-Transformed OFDM

    公开(公告)号:US20200177422A1

    公开(公告)日:2020-06-04

    申请号:US16780620

    申请日:2020-02-03

    Applicant: Apple Inc.

    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.

    Methods and systems for OFDM using code division multiplexing

    公开(公告)号:US10541773B2

    公开(公告)日:2020-01-21

    申请号:US16374147

    申请日:2019-04-03

    Applicant: Apple Inc.

    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

    公开(公告)号:US10476719B2

    公开(公告)日:2019-11-12

    申请号:US16433273

    申请日:2019-06-06

    Applicant: Apple Inc.

    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).

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