Pulse or digital communications – Systems using alternating or pulsating current – Plural channels for transmission of a single pulse train
Reexamination Certificate
2007-10-18
2009-06-23
Bocure, Tesfaldet (Department: 2611)
Pulse or digital communications
Systems using alternating or pulsating current
Plural channels for transmission of a single pulse train
C375S347000, C375S144000
Reexamination Certificate
active
07551682
ABSTRACT:
Techniques are provided for selecting one or more downlink beamforming vectors for a wireless channel to create beamformed signals between a first wireless communication device, e.g., a base transceiver station (BTS) and a second wireless communication device, e.g., a mobile station (MS). The method comprises estimating a downlink channel covariance matrix from an uplink covariance matrix of the wireless channel, wherein the uplink covariance matrix is computed based on uplink signals received at the first wireless communication device from the second wireless communication device. A plurality of candidate downlink beamforming weighting vectors are generated from the uplink covariance matrix. Each of the candidate downlink beamforming weighting vectors are applied to a corresponding downlink signal for transmission via the plurality of antennas of the first wireless communication device to the second wireless communication device such that multiple downlink signals are transmitted from the first wireless communication device to the second wireless communication device, each downlink signal with a different one of the plurality of candidate downlink beamforming weighting vectors. Feedback messages are received at the first wireless communication device from the second wireless communication device, where the feedback messages indicate reception quality of downlink signals received by the second wireless communication device from the first wireless communication device. One or more of the candidate downlink beamforming weighting vectors is selected for use in transmitting downlink signals from the first wireless communication device to the second wireless communication device based on the feedback messages.
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Jin Hang
Na Yanxin
Bocure Tesfaldet
Cisco Technology Inc.
Edell Shapiro & Finnan LLC
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