Systems and methods for use with orthogonal frequency division multiplexing

    公开(公告)号:US10985892B2

    公开(公告)日:2021-04-20

    申请号:US16591711

    申请日:2019-10-03

    Applicant: Apple Inc.

    Abstract: Systems and methods are provided for enabling H-ARQ communication between a base station and one or more wireless terminals. Methods for enabling incremental redundancy (IR) based H-ARQ, Chase based H-ARQ and Space-Time Code combining (STC) based H-ARQ between devices for down⋅link and up-link direction transmissions are provided in the form of an information element (IE) for use with a Normal MAP convention as currently accepted in the draft version standard of IEEE 802.16. In addition, embodiments of the invention provide a resource management scheme to protect a network from abuse of resources from a wireless terminal not registered with the network. Components of the down-link and up-link mapping components of a data frame transmitted from the base station to one or more wireless terminals included messages that are readable by all wireless terminals as well as some messages that are encrypted and only readable by wireless terminals that are authenticated as being registered with the network.

    OFDM system with reverse link interference estimation

    公开(公告)号:US10965389B2

    公开(公告)日:2021-03-30

    申请号:US15869863

    申请日:2018-01-12

    Applicant: APPLE INC.

    Abstract: A new method of performing interference estimation to allow the data packets to be efficiently delivered in an OFDM system. The interference estimation is performed on average over each frame for each mobile station individually in both frequency and time domains. Based on the estimated interference, the CIR can be determined by the BTS based on channel response estimates made by the BTS, or by the MS based on channel response estimates made for the uplink assuming a symmetrical channel. Numerical results show that the CIR estimation error could be very small if a sub-channel is considered as the minimum transmission unit. In terms of the aggregate throughput, the interference estimation method can provide a significant gain.

    Pilot symbol patterns for transmission through a plurality of antennas

    公开(公告)号:US10700905B2

    公开(公告)日:2020-06-30

    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).

    Adaptive transmission systems and methods

    公开(公告)号:US10686512B2

    公开(公告)日:2020-06-16

    申请号:US15796071

    申请日:2017-10-27

    Applicant: APPLE INC.

    Abstract: Spatial multiplexing and transmit diversity can improve the capacity of a wireless communication system. The system and method adapts communication schemes for communication systems with multiple antennas utilizing at least two transmission modes. The at least two transmission modes can, but are not necessarily, used for uplink communications. The two transmission modes may be chosen from the group consisting of a single antenna mode, a diversity mode a spatial multiplexed mode and a mixed diversity and spatial multiplexed mode. The at least two transmission modes may involve adaptation among multiple transmitters. At least one receiver may indicate a transmission mode to be used by a transmitter for a subsequent transmission. A transmitter may determine a transmission mode to be used for a subsequent transmission. The transmission mode can be based on channel sounding.

    Pilot Scheme for a MIMO Communication System

    公开(公告)号:US20200177246A1

    公开(公告)日:2020-06-04

    申请号:US16786679

    申请日:2020-02-10

    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.

    Methods and Systems For Enabling Feedback In Wireless Communication Networks

    公开(公告)号:US20200162138A1

    公开(公告)日:2020-05-21

    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.

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