System access and synchronization methods for MIMO OFDM communications systems and physical layer packet and preamble design

    公开(公告)号:US10237794B2

    公开(公告)日:2019-03-19

    申请号:US15355440

    申请日:2016-11-18

    Applicant: Apple Inc.

    Abstract: A method and apparatus are provided for performing acquisition, synchronization and cell selection within an MIMO-OFDM communication system. A coarse synchronization is performed to determine a searching window. A fine synchronization is then performed by measuring correlations between subsets of signal samples, whose first signal sample lies within the searching window, and known values. The correlations are performed in the frequency domain of the received signal. In a multiple-output OFDM system, each antenna of the OFDM transmitter has a unique known value. The known value is transmitted as pairs of consecutive pilot symbols, each pair of pilot symbols being transmitted at the same subset of sub-carrier frequencies within the OFDM frame.

    METHOD AND SYSTEM FOR USER EQUIPMENT LOCATION DETERMINATION ON A WIRELESS TRANSMISSION SYSTEM

    公开(公告)号:US20190033424A1

    公开(公告)日:2019-01-31

    申请号:US16136862

    申请日:2018-09-20

    Applicant: Apple Inc.

    CPC classification number: G01S5/10 H04L5/0007 H04W24/10 H04W64/00

    Abstract: Neighbor cell hearability can be improved by including an additional reference signal that can be detected at a low sensitivity and a low signal-to-noise ratio, by introducing non-unity frequency reuse for the signals used for a time difference of arrival (TDOA) measurement, e.g., orthogonality of signals transmitted from the serving cell sites and the various neighbor cell sites. The new reference signal, called the TDOA-RS, is proposed to improve the hearability of neighbor cells in a cellular network that deploys 3GPP EUTRAN (LTE) system, and the TDOA-RS can be transmitted in any resource blocks (RB) for PDSCH and/or MBSFN subframe, regardless of whether the latter is on a carrier supporting both PMCH and PDSCH or not. Besides the additional TDOA-RS reference signal, an additional synchronization signal (TDOA-sync) may also be included to improve the hearability of neighbor cells.

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