METHOD AND SYSTEM FOR CHANNEL ESTIMATION IN AN OFDM BASED MIMO SYSTEM
Upon receiving spatially independent OFDM signals from multiple transmit antennas coupled to a single transmitter, a receiver comprising multiple receive antennas operably coupled to multiple RF chains adjusts phase and/or gain of a portion of signal components received over multiple receive antennas coupled to the same RF chain. A combined channel estimate for the RF chain is generated using corresponding frequency domain samples of the adjusted signal components. Individual channel estimates are generated from the generated combined channel estimate. Phase rotation and/or gain adjustment information are determined to adjust signal components received over additional receive antennas coupled to the RF chain. The phase and/or gain adjusted signal components are combined with signal components over a selected reference receive antenna coupled to the RF chain for RF processing. The RF processed signal components are converted into corresponding frequency domain samples to generate individual channel estimates for the phase rotation and/or gain adjustment.
1 . A method for processing signals in a communication system, the method comprising:
performing by one or more processors and/or circuits in a receiver, wherein said receiver comprises a plurality of receive antennas operably coupled to a plurality of radio frequency (RF) chains:
receiving spatially independent Orthogonal Frequency Division Multiplexing (OFDM) signals, via said plurality of receive antennas, wherein said spatially independent OFDM signals are transmitted from a plurality of transmit antennas communicatively coupled to a single transmitter;
adjusting phase and/or gain of a portion of signal components of said received OFDM signals, wherein said portion of said signal components are received via two or more receive antennas communicatively coupled to one of said plurality of RF chains;
for a plurality of channels between said plurality of transmit antennas and said two or more receive antennas communicatively coupled to said one of said plurality of RF chains, generating a combined channel estimate utilizing corresponding frequency domain samples of said phase and/or gain adjusted portion of signal components of said received OFDM signals; and
generating an individual channel estimate for each of said plurality of channels based on said generated combined channel estimate.
2 . The method according to claim 1 , comprising selecting one of said two or more receive antennas coupled to said one of said plurality of RF chains as a reference receive antenna for said one of said plurality of RF chains.
3 . The method according to claim 2 , comprising determining phase rotation and/or gain adjustment information with respect to said selected reference receive antenna for each additional receive antenna coupled to said one of said plurality of RF chains.
4 . The method according to claim 3 , comprising phase rotating and/or gain adjusting said portion of said signal components of said received OFDM signals over said each additional receive antenna coupled to said one of said plurality of RF chains based on said corresponding determined phase rotation and/or gain adjustment information.
5 . The method according to claim 4 , comprising combining said phase rotated and/or gain adjusted signal components with said portion of said signal components of said received OFDM signals over said selected reference receive antenna.
6 . The method according to claim 5 , comprising RF processing said combined signal components using said one of said plurality of RF chains.
7 . The method according to claim 6 , comprising converting said RF processed signal components into corresponding frequency domain samples.
8 . The method according to claim 7 , comprising generating said combined channel estimate for said plurality of channels based on said resulting frequency domain samples.
9 . The method according to claim 8 , comprising generating an individual channel estimate for each of said plurality of channels based on said generated combined channel estimate.
10 . The method according to claim 9 , comprising determining said phase rotation and/or gain adjustment information with respect to said selected reference receive antenna for said each additional receive antenna coupled to said one of said plurality of RF chains based on said generated corresponding individual channel estimate.
11 . A system for signal processing, the system comprising:
one or more processors and/or circuits for use within a receiver, wherein said receiver comprises a plurality of receive antennas operably coupled to a plurality of radio frequency (RF) chains, said one or more processors and/or circuits being operable to:
receive spatially independent Orthogonal Frequency Division Multiplexing (OFDM) signals, via said plurality of receive antennas, wherein said spatially independent OFDM signals are transmitted from a plurality of transmit antennas communicatively coupled to a single transmitter;
adjust phase and/or gain of a portion of signal components of said received OFDM signals, wherein said portion of said signal components are received via two or more receive antennas communicatively coupled to one of said plurality of RF chains;
for a plurality of channels between said plurality of transmit antennas and said two or more receive antennas communicatively coupled to said one of said plurality of RF chains, generate a combined channel estimate utilizing corresponding frequency domain samples of said phase and/or gain adjusted portion of signal components of said received OFDM signals; and
generate an individual channel estimate for each of said plurality of channels based on said generated combined channel estimate.
12 . The system according to claim 11 , wherein said one or more processors and/or circuits are operable to select one of said two or more receive antennas coupled to said one of said plurality of RF chains as a reference receive antenna for said one of said plurality of RF chains.
13 . The system according to claim 12 , wherein said one or more processors and/or circuits are operable to determine phase rotation and/or gain adjustment information with respect to said selected reference receive antenna for each additional receive antenna coupled to said one of said plurality of RF chains.
14 . The system according to claim 13 , wherein said one or more processors and/or circuits are operable to phase rotate and/or gain adjust said portion of said signal components of said received OFDM signals over said each additional receive antenna coupled to said one of said plurality of RF chains based on said corresponding determined phase rotation and/or gain adjustment information.
15 . The system according to claim 14 , wherein said one or more processors and/or circuits are operable to combine said phase rotated and/or gain adjusted signal components with said portion of said signal components of said received OFDM signals over said selected reference receive antenna.
16 . The system according to claim 15 , wherein said one or more processors and/or circuits are operable to RF process said combined signal components using said one of said plurality of RF chains.
17 . The system according to claim 16 , wherein one or more processors and/or circuits are operable to convert said RF processed signal components into corresponding frequency domain samples.
18 . The system according to claim 16 , wherein one or more processors and/or circuits are operable to generate said combined channel estimate for said plurality of channels based on said resulting frequency domain samples.
19 . The system according to claim 16 , wherein one or more processors and/or circuits are operable to generate an individual channel estimate for each of said plurality of channels based on said generated combined channel estimate.
20 . The system according to claim 19 , wherein one or more processors and/or circuits are operable to determine said phase rotation and/or gain adjustment information with respect to said selected reference receive antenna for said each additional receive antenna coupled to said one of said plurality of RF chains based on said generated corresponding individual channel estimate.