MIMO WLAN system
First Claim
1. A method of performing channel estimation in a wireless multiple-input multiple-output (MIMO) communication system, comprising:
- receiving a steered pilot via at least one eigenmode of an uplink from a user terminal, the steered pilot being transmitted via a plurality of antennas at the user terminal;
estimating a channel response of the at least one eigenmode of the uplink for the user terminal based on the received steered pilot;
deriving a matched filter based on the estimated channel response of the at least one eigenmode of the uplink;
receiving a data transmission via the at least one eigenmode of the uplink from the user terminal; and
using the matched filter for matched filtering of the data transmission.
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Accused Products
Abstract
A multiple-access MIMO WLAN system that employs MIMO, OFDM, and TDD. The system (1) uses a channel structure with a number of configurable transport channels, (2) supports multiple rates and transmission modes, which are configurable based on channel conditions and user terminal capabilities, (3) employs a pilot structure with several types of pilot (e.g., beacon, MIMO, steered reference, and carrier pilots) for different functions, (4) implements rate, timing, and power control loops for proper system operation, and (5) employs random access for system access by the user terminals, fast acknowledgment, and quick resource assignments. Calibration may be performed to account for differences in the frequency responses of transmit/receive chains at the access point and user terminals. The spatial processing may then be simplified by taking advantage of the reciprocal nature of the downlink and uplink and the calibration.
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Citations
11 Claims
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1. A method of performing channel estimation in a wireless multiple-input multiple-output (MIMO) communication system, comprising:
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receiving a steered pilot via at least one eigenmode of an uplink from a user terminal, the steered pilot being transmitted via a plurality of antennas at the user terminal; estimating a channel response of the at least one eigenmode of the uplink for the user terminal based on the received steered pilot; deriving a matched filter based on the estimated channel response of the at least one eigenmode of the uplink; receiving a data transmission via the at least one eigenmode of the uplink from the user terminal; and using the matched filter for matched filtering of the data transmission.
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2. A method of performing channel estimation in a wireless multiple-input multiple-output (MIMO) communication system, comprising:
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receiving a steered pilot via at least one eigenmode of an uplink from a user terminal, the steered pilot being transmitted via a plurality of antennas at the user terminal; estimating a channel response of the at least one eigenmode of the uplink for the user terminal based on the received steered pilot; deriving at least one steering vector based on the estimated channel response of the at least one eigenmode of the downlink; and using the at least one steering vector for data transmission on the at least one eigenmode of the downlink to the user terminal. - View Dependent Claims (3, 4)
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5. An apparatus in a wireless multiple-input multiple-output (MIMO) communication system, comprising:
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a receive spatial processor operative to receive a steered pilot via at least one eigenmode of an uplink from a user terminal, the steered pilot being transmitted via a plurality of antennas at the user terminal; and a controller operative to estimate a channel response of the at least one eigenmode of the uplink for the user terminal based on the received steered pilot, wherein the controller is further operative to derive a matched filter based on the estimated channel response of the at least one eigenmode of the uplink; wherein the receive spatial processor operative to receive a data transmission via the at least one eigenmode of the uplink from the user terminal and use the matched filter for matched filtering of the data transmission.
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6. An apparatus in a wireless multiple-input multiple-output (MIMO) communication system, comprising:
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a receive spatial processor operative to receive a steered pilot via at least one eigenmode of an uplink from a user terminal, the steered pilot being transmitted via a plurality of antennas at the user terminal; a controller operative to estimate a channel response of the at least one eigenmode of the uplink for the user terminal based on the received steered pilot, to estimate a channel response of at least one eigenmode of a downlink for the user terminal based on the received steered pilot, and to derive at least one steering vector based on the estimated channel response of the at least one eigenmode of the downlink; and a transmit spatial processor operative to use the at least one steering vector for data transmission on the at least one eigenmode of the downlink to the user terminal.
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7. An apparatus in a wireless multiple-input multiple-output (MIMO) communication system, comprising:
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means for receiving a steered pilot via at least one eigenmode of an uplink from a user terminal, the steered pilot being transmitted via a plurality of antennas at the user terminal; and means for estimating a channel response of the at least one eigenmode of the uplink for the user terminal based on the received steered pilot; means for deriving a matched filter based on the estimated channel response of the at least one eigenmode of the uplink; means for receiving a data transmission via the at least one eigenmode of the uplink from the user terminal; and means for using the matched filter for matched filtering of the data transmission. - View Dependent Claims (8)
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9. An apparatus in a wireless multiple-input multiple-output (MIMO) communication system, comprising:
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means for receiving a steered pilot via at least one eigenmode of an uplink from a user terminal, the steered pilot being transmitted via a plurality of antennas at the user terminal; means for estimating a channel response of the at least one eigenmode of the uplink for the user terminal based on the received steered pilot; means for estimating a channel response of at least one eigenmode of a downlink for the user terminal based on the received steered pilot; means for deriving at least one steering vector based on the estimated channel response of the at least one eigenmode of the downlink; and means for using the at least one steering vector for data transmission on the at least one eigenmode of the downlink to the user terminal.
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10. A memory unit used in a wireless multiple-input multiple-output (MIMO) communication system having software codes stored thereon, the software codes being executable by one or more processors and the software codes comprising:
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codes for receiving a steered pilot via at least one eigenmode of an uplink from a user terminal, the steered pilot being transmitted via a plurality of antennas at the user terminal; codes for estimating a channel response of the at least one eigenmode of the uplink for the user terminal based on the received steered pilot; codes for deriving a matched filter based on the estimated channel response of the at least one eigenmode of the uplink; codes for receiving a data transmission via the at least one eigenmode of the uplink from the user terminal; and codes for using the matched filter for matched filtering of the data transmission.
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11. A memory unit used in a wireless multiple-input multiple-output (MIMO) communication system having software codes stored thereon, the software codes being executable by one or more processors and the software codes comprising:
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codes for receiving a steered pilot via at least one eigenmode of an uplink from a user terminal, the steered pilot being transmitted via a plurality of antennas at the user terminal; codes for estimating a channel response of the at least one eigenmode of the uplink for the user terminal based on the received steered pilot; codes for estimating a channel response of at least one eigenmode of a downlink for the user terminal based on the received steered pilot; codes for deriving at least one steering vector based on the estimated channel response of the at least one eigenmode of the downlink; and codes for using the at least one steering vector for data transmission on the at least one eigenmode of the downlink to the user terminal.
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Specification