Methods and systems for enabling feedback in wireless communication networks

    公开(公告)号:US11258489B2

    公开(公告)日:2022-02-22

    申请号:US16749687

    申请日:2020-01-22

    Applicant: APPLE INC.

    Abstract: Aspects of the present invention provide additional MAC functionality to support the PHY features of a wireless communication system framework. The additional MAC functionality aids in enabling feedback from wireless terminals to base stations. In some aspects of the invention the feedback is provided on an allocated feedback channel. In other aspects of the invention the feedback is provided by MAC protocol data units (PDU) in a header, mini-header, or subheader. The feedback may be transmitted from the wireless terminal to the base station autonomously by the wireless terminal or in response to an indication from the base station that feedback is requested. Aspects of the invention also provide for allocating feedback resources to form a dedicated feedback channel. One or more of these enhancements is included in a given implementation. Base stations and wireless terminals are also described upon which methods described herein can be implemented.

    Efficient location updates, paging and short bursts

    公开(公告)号:US10973011B2

    公开(公告)日:2021-04-06

    申请号:US16914718

    申请日:2020-06-29

    Applicant: Apple Inc.

    Abstract: A mobile terminal in a wireless communication network may be one of several modes of operation. When in an idle mode, the mobile terminal may avoid a lengthy random access procedure normally associated with responding to a page from a base station, if the base station includes in the page an indication of a resource that the mobile terminal may utilize when responding to the page. Additionally, the mobile terminal may transmit an efficient location update MAC header to a base station, whether prompted to by a page from the base station or not. Furthermore, without leaving the idle mode or a sleep mode, the mobile terminal may exchange short data burst messages with a base station.

    Preambles in OFDMA system
    204.
    发明授权

    公开(公告)号:US10826744B2

    公开(公告)日:2020-11-03

    申请号:US16249672

    申请日:2019-01-16

    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-1 and Preamble-2, which may be used in different systems, including multioutput, multi-input (MIMO) systems.

    Pilot scheme for a MIMO communication system

    公开(公告)号:US10797764B2

    公开(公告)日:2020-10-06

    申请号:US16519158

    申请日:2019-07-23

    Applicant: Apple Inc.

    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.

    Precoding in high-order MIMO
    206.
    发明授权

    公开(公告)号:US10693535B2

    公开(公告)日:2020-06-23

    申请号:US15093924

    申请日:2016-04-08

    Applicant: Apple Inc.

    Abstract: A high-order Multiple-Input-Multiple-Output (MIMO) transmitter implementing a covariance-based precoding scheme that exploits transmit channel correlation and a method of operation thereof are provided. In one embodiment, covariance-based precoding is performed at the high-order MIMO transmitter based on feedback from a remote high-order MIMO receiver regarding a covariance-based precoding matrix. The covariance-based precoding matrix is, or is derived from, a transmit channel correlation matrix determined by the high-order MIMO receiver for the high-order MIMO transmitter. The covariance-based precoding provides a beam-forming effect when there is a relatively high degree of transmit channel correlation, thereby improving performance of the high-order MIMO transmitter. Further, because changes in the transmit channel correlation occur relatively slowly over time, feedback overhead requirements are substantially reduced as compared to that required for traditional MIMO precoding schemes.

    Methods and systems for enabling feedback in wireless communication networks

    公开(公告)号:US10581500B2

    公开(公告)日:2020-03-03

    申请号:US16373183

    申请日:2019-04-02

    Applicant: APPLE INC.

    Abstract: Aspects of the present invention provide additional MAC functionality to support the PHY features of a wireless communication system framework. The additional MAC functionality aids in enabling feedback from wireless terminals to base stations. In some aspects of the invention the feedback is provided on an allocated feedback channel. In other aspects of the invention the feedback is provided by MAC protocol data units (PDU) in a header, mini-header, or subheader. The feedback may be transmitted from the wireless terminal to the base station autonomously by the wireless terminal or in response to an indication from the base station that feedback is requested. Aspects of the invention also provide for allocating feedback resources to form a dedicated feedback channel. One or more of these enhancements is included in a given implementation. Base stations and wireless terminals are also described upon which methods described herein can be implemented.

    Pilot Symbol Patterns for Transmission through a Plurality of Antennas

    公开(公告)号:US20200067749A1

    公开(公告)日:2020-02-27

    申请号:US16666650

    申请日:2019-10-29

    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).

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

    公开(公告)号:US10554464B2

    公开(公告)日:2020-02-04

    申请号:US16273302

    申请日:2019-02-12

    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.

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