Method and system for combining DFT-transformed OFDM and non-transformed OFDM

    公开(公告)号:US10237106B2

    公开(公告)日:2019-03-19

    申请号:US15790678

    申请日:2017-10-23

    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.

    PILOT SYMBOL PATTERNS FOR TRANSMIT ANTENNAS
    19.
    发明申请
    PILOT SYMBOL PATTERNS FOR TRANSMIT ANTENNAS 审中-公开
    发射天线的引导符号模式

    公开(公告)号:US20160164706A1

    公开(公告)日:2016-06-09

    申请号:US15046934

    申请日:2016-02-18

    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).

    Abstract translation: 一种用于改善OFDM通信系统内的信道估计的方法和装置。 OFDM中的信道估计通常借助于导频符号来执行。 导频符号通常在时间和频率上间隔开。 将导频符号插入的频率和时间的集合称为导频模式。 在一些情况下,导频图案是对角线形格子,规则的或不规则的。 该方法首先在较大相干性(时间或频率)的方向内插。 使用这些测量,导频符号在更快变化方向上的密度将增加,从而改善信道估计而不增加开销。 因此,第一内插步骤的结果然后可以用于辅助尺寸较小的相干性(时间或频率)的内插。

    Wireless feedback system and method
    20.
    发明授权
    Wireless feedback system and method 有权
    无线反馈系统及方法

    公开(公告)号:US09136923B2

    公开(公告)日:2015-09-15

    申请号:US14551053

    申请日:2014-11-23

    Applicant: Apple Inc.

    Abstract: A codebook C is provided in a MIMO transmitter as well as a MIMO receiver. The codebook C will include M codewords ci, where i is a unique codeword index for each codeword ci. Each codeword defines weighting factors to apply to the MIMO signals, and may correspond to channel matrices or vectors to apply to the MIMO signals prior to transmission from the respective antennas of the MIMO transmitter. The present invention creates codeword subsets S1 for each codeword c1 of the codebook C. Each codeword subset S1 defines L codewords cj, which are selected from all the codewords ci in the codebook C. The codewords cj in a codeword subset S1 are the L codewords in the entire codebook that best correlate with the corresponding codeword ci.

    Abstract translation: 码本C被提供在MIMO发射机以及MIMO接收机中。 码本C将包括M个码字ci,其中i是每个码字ci的唯一码字索引。 每个码字定义了应用于MIMO信号的加权因子,并且可以对应于在从MIMO发射机的各个天线发送之前应用于MIMO信号的信道矩阵或向量。 本发明为码本C的每个码字c1创建码字子集S1。每个码字子集S1定义从码本C中的所有码字ci中选择的L个码字cj。码字子集S1中的码字cj是L个码字 在整个码本中与相应的码字ci最相关。

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