Method and apparatus for interference suppression in orthogonal frequency division multiplexed (OFDM) wireless communication systems
First Claim
1. An apparatus for processing signals received from a plurality of remote transceivers, the apparatus comprising:
- at least two beamformers, each beamformer being associated with a corresponding antenna sub-array having at least two antenna elements, and being configured to;
receive at least two base signals associated with at least two carrier signals corresponding to a frequency bin allocated to a user, the at least two carrier signals being associated with the at least two antenna elements of the corresponding antenna sub-array; and
generate an output signal as a weighted sum of the at least two base signals, associated with the at least two carrier signals, based on directions of arrival of the at least two carrier signals; and
a spatial diversity combiner configured to selectively combine at least two output signals, corresponding to the frequency bin allocated to the user, of the at least two beamformers.
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Accused Products
Abstract
A method and apparatus for interference suppression in wireless communication systems, especially Orthogonal Frequency Division Multiplexed (OFDM) systems, is presented. The array apparatus includes a two-tier adaptive array system, which provides for both spatial diversity and beamforming at the uplink and includes sub-arrays spaced at a distance sufficient to provide spatial diversity and support beamforming or scanning. A Direction of Arrival (DOA) of signals impinging upon the array can be calculated by comparing signals from sub-array elements. Each sub-array can be filtered or beamformed to provide high gain to desired signals received from the DOA (which may be a multipath signal) while simultaneously dampening-out undesired signals, such as co-channel interference (CCI) in the frequency band of operation. The DOA is also used for allocating frequency bins for data signals, such as in an OFDM system, to provide weighted guidelines for bin allocation to maximize received signal power.
132 Citations
20 Claims
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1. An apparatus for processing signals received from a plurality of remote transceivers, the apparatus comprising:
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at least two beamformers, each beamformer being associated with a corresponding antenna sub-array having at least two antenna elements, and being configured to; receive at least two base signals associated with at least two carrier signals corresponding to a frequency bin allocated to a user, the at least two carrier signals being associated with the at least two antenna elements of the corresponding antenna sub-array; and generate an output signal as a weighted sum of the at least two base signals, associated with the at least two carrier signals, based on directions of arrival of the at least two carrier signals; and a spatial diversity combiner configured to selectively combine at least two output signals, corresponding to the frequency bin allocated to the user, of the at least two beamformers. - View Dependent Claims (2, 3, 4)
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5. An apparatus for processing signals received from a plurality of remote transceivers, the apparatus comprising:
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at least two beamformers, each beamformer being configured to adjust gains applied to at least two base signals, associated with at least two carrier signals, based on directions of arrival of the at least two carrier signals, and to produce at least one output signal; a spatial diversity combiner configured to selectively combine at least two output signals of the at least two beamformers; and a processor configured to; monitor information related to a plurality of frequency bins; and assign signals associated with a remote transceiver to frequency bins according to at least the following criteria;
(1) signals associated with a remote transceiver are assigned to frequency bins that are separated apart in the frequency domain and (2) signals assigned to neighboring frequency bins have substantially different directions of arrival. - View Dependent Claims (6, 7, 8)
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9. A method for processing signals received from a plurality of remote transceivers, the method comprising, in a receiver system including a spatial diversity combiner and at least two beamformers:
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receiving a plurality of base signals from at least two antenna sub-arrays each having at least two antenna elements, the plurality of base signals associated with at least two carrier signals corresponding to a frequency bin allocated to a user, the at least two carrier signals being associated with the at least two antenna elements of the corresponding antenna sub-array; receiving the plurality of base signals to one of the at least two antenna sub-arrays by an associated one of the at least two beamformers; receiving the plurality of base signals to another of the at least two antenna sub-arrays by an associated one of the at least two beamformers; generating, by each beamformer of the at least two beamformers, an output signal as a weighted sum of the at least two of the plurality of base signals based on directions of arrival of the at least two corresponding carrier signals; and spatial diversity combining the output signals, corresponding to the frequency bin allocated to the user, of the at least two beamformers. - View Dependent Claims (10, 11)
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12. A method for processing signals received from a plurality of remote transceivers, the method comprising:
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forming signal beams using base signals, each signal beam being formed using at least two base signals, associated with at least two carrier signals, based on directions of arrival of the at least two carrier signals; spatial diversity combining at least two of the formed signal beams; monitoring information related to a plurality of frequency bins; and assigning signals associated with a remote transceiver to frequency bins according to at least the following criteria;
(1) signals associated with a remote transceiver are assigned frequency bins that are separated apart in the frequency domain and (2) signals assigned to neighboring frequency bins have substantially different directions of arrival. - View Dependent Claims (13, 14, 15)
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16. A non-transitory computer readable medium including computer software for processing signals received from a plurality of remote transceivers, the computer software when executed by a processor causes an apparatus to:
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receive at least two base signals associated with at least two carrier signals corresponding to a frequency bin allocated to a user, the at least two carrier signals being associated with at least two antenna elements of a corresponding antenna sub-array; and generate an output signal as a weighted sum of the at least two base signals, associated with the at least two carrier signals, based on directions of arrival of the at least two carrier signals; and spatial diversity combine the output signals, corresponding to the frequency bin allocated to the user, of at least two beamformers. - View Dependent Claims (17, 18, 19, 20)
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Specification