Pulse or digital communications – Systems using alternating or pulsating current – Plural channels for transmission of a single pulse train
Reexamination Certificate
2007-04-17
2007-04-17
Tse, Young T. (Department: 2611)
Pulse or digital communications
Systems using alternating or pulsating current
Plural channels for transmission of a single pulse train
C375S260000
Reexamination Certificate
active
10783175
ABSTRACT:
The downlink and uplink are calibrated to account for differences in the responses of transmit and receive chains at an access point and a user terminal. For initial calibration, the access point and user terminal transmit MIMO pilots on the downlink and uplink, which are used to derive channel estimates including the responses of the applicable transmit/receive chains. Correction matrices {circumflex over (K)}apand {circumflex over (K)}utare derived based on these channel estimates and thereafter used by the access point and user terminal, respectively. For follow-on calibration, one entity transmits a MIMO pilot and a steered reference. The other entity derives a first transmit matrix based on the steered reference and a second transmit matrix based on the MIMO pilot and calibration error matrices Qapand Qut, which contain estimates of the errors in {circumflex over (K)}apand {circumflex over (K)}ut, respectively. Qapand Qutmay be iteratively adjusted based on an adaptive procedure to minimize the errors between the two transmit matrices.
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Howard Steven J.
Ketchum John W.
Wallace Mark S.
Walton J. Rodney
Milikovsky Dmitry R.
Minhas Sandip (Micky) S.
Qualcomm Incorporated
Rouse Thomas R.
Tse Young T.
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