利索-全球专利检索

  1. 登录
  2. 注册

搜索结果

10 条记录 (耗时 0.011 秒)

    METHOD AND APPARATUS FOR PERFORMING CYCLIC-SHIFT DIVERSITY WITH BEAMFORMING
    1.
    发明公开
    METHOD AND APPARATUS FOR PERFORMING CYCLIC-SHIFT DIVERSITY WITH BEAMFORMING 审中-公开
    于执行循环的方法和装置抵消RAYS生产多样性

    公开(公告)号：EP1972064A2

    公开(公告)日：2008-09-24

    申请号：EP06848387.4

    申请日：2006-12-29

    申请人： Motorola, Inc.

    发明人： VOOK, Frederick, W. ,  THOMAS, Timothy, A. ,  ZHUANG, Xiangyang

    IPC分类号： H04B1/38

    CPC分类号： H04B7/0671

    摘要： Cyclic-shift diversity transmission and optional per-subcarrier transmit beamforming within a same time interval (e.g., OFDM symbol interval) takes place. The CSD transmission technique circularly shifts the IFFT output prior to any cyclic prefix insertion and has the effect of putting a subcarrier and antenna dependent phase shift in the effective channel response from each transmit antenna. To properly perform transmit adaptive array (TXAA) transmission within an OFDM symbol interval that is being circularly shifted by the CSD transmission technique, the TXAA weights will account for the frequency domain phase shift created by the CSD circular shift operation.

    METHOD AND APPARATUS FOR ACCESSING A WIRELESS COMMUNICATION SYSTEM
    4.
    发明公开
    METHOD AND APPARATUS FOR ACCESSING A WIRELESS COMMUNICATION SYSTEM 有权
    方法和装置接入无线通信系统

    公开(公告)号：EP1762019A2

    公开(公告)日：2007-03-14

    申请号：EP05762643.4

    申请日：2005-06-23

    申请人： MOTOROLA, INC.

    发明人： ZHUANG, Xiangyang

    IPC分类号： H04B7/216

    CPC分类号： H04L27/2613 ,  H04L5/0007 ,  H04L25/0212 ,  H04L25/022 ,  H04L25/0226 ,  H04L25/0228 ,  H04L27/2607

    摘要： Access to a wireless communication system (100) by a subscriber station (101-103) is facilitated by selecting (705) an access sequence from a set of sequences that have been identified to have a low average of peak-to-average-power-ratios of access signals generated by the set of sequences and also based on a good cross-correlation of the access signals; forming (714) the access waveform by generating an access signal using the access sequence and appending in the time domain a cyclic prefix to the access signal; and transmitting (715) the access waveform. In some implementations, the access waveform is cyclically shifted (820) before the cyclic prefix is appended, and in some implementations, the signal is transmitted (710, 810) in a randomly selected sub-band of an access interval.

    CHANNEL ESTIMATOR WITH HIGH NOISE SUPPRESSION AND LOW INTERPOLATION ERROR FOR OFDM SYSTEMS
    8.
    发明公开
    CHANNEL ESTIMATOR WITH HIGH NOISE SUPPRESSION AND LOW INTERPOLATION ERROR FOR OFDM SYSTEMS 有权
    高，低降噪插值OFDM系统的信道预测

    公开(公告)号：EP2135410A2

    公开(公告)日：2009-12-23

    申请号：EP08727983.2

    申请日：2008-01-21

    申请人： Motorola, Inc.

    发明人： SAYANA, Krishna Kamal ,  ZHUANG, Xiangyang ,  NOLLETT, Bryan S.

    IPC分类号： H04L25/02

    CPC分类号： H04L27/2647 ,  H04L25/022 ,  H04L25/0228 ,  H04L25/025

    摘要： A receiver with DFT based channel estimation having good noise suppression for both high and low signal-to-noise ratios providing advantages over conventional DFT estimators and Minimum-Mean-Square-Error (MMSE) estimators. The use of MMSE may be incorporated for estimation at the band edges providing further improvements. The received signal in the time domain, is transformed to the frequency-domain received signal via an N-point FFT (501). The frequency-domain received signal at the pilot locations is then used to obtain a 'noisy' channel estimates at the pilot subcarriers by dividing the known pilot symbols in (503). Uniformly spaced pilots are assumed over a window of usable subcarriers. Padding is applied to the initial channel estimates at both sides of the band to account for unused subcarriers such as guard spacing. Weighting factors during power estimation may take into account various noise characteristics such as combinations of known and time-limited noise power characteristics.