Method and apparatus for multiple-input multiple-output operation
First Claim
1. A method for receiving multiple-input multiple-output (MIMO) transmissions, the method comprising:
- a wireless transmit/receive unit (WTRU) receiving at least one of a plurality of downlink transmissions from an eNodeB on at least one of a plurality of spatial layers, wherein the plurality of spatial layers are transmitted to a plurality of WTRUs for multi-user MIMO, and wherein the at least one spatial layer is used for reception by the WTRU;
the WTRU receiving at least one WTRU-specific reference signal corresponding to the at least one downlink transmission; and
the WTRU decoding the at least one downlink transmission based on the at least one corresponding WTRU-specific reference signal for the WTRU,wherein resource elements are allocated to resource blocks, and the resource blocks include WTRU-specific reference signals for the plurality of WTRUs and the downlink transmission such that WTRU-specific reference signals for different sub-groups of antenna ports are multiplexed onto different subcarriers in a frequency domain and the WTRU-specific reference signals of the same sub-group of antennas ports are each applied with a different orthogonal cover code in a time domain,wherein each sub-group of antenna ports includes at least two antenna ports, andwherein resource elements used for the downlink transmission are rate matched around resource elements allocated for the at least one WTRU-specific reference signal for the WTRU on at least one antenna port in one sub-group and are rate matched around resource elements allocated for at least one WTRU-specific reference signal for at least another WTRU on at least one antenna port in another sub-group, wherein the resource elements allocated for the at least one WTRU-specific reference signal for at least another WTRU are muted.
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Accused Products
Abstract
A wireless transmit/receive unit (WTRU) receives a downlink transmission from an eNodeB including a plurality of spatial layers transmitted to a plurality of WTRUs paired for multi-user MIMO. The WTRU decodes the downlink transmission based on a corresponding WTRU-specific reference signal. WTRU-specific reference signals are multiplexed using a frequency and code division multiplexing. WTRU-specific reference signals for different sub-group of antenna ports are multiplexed onto different subcarriers in a frequency domain and the WTRU-specific reference signals of the same sub-group of antennas ports are multiplied by an orthogonal cover code. The resource elements used for the WTRU-specific reference signals on antenna ports in one sub-group may be muted on antenna ports in another sub-group. A WTRU may transmit the uplink demodulation reference signal without precoding. The number of resource blocks allocated for the demodulation reference signal may be greater than the number of resource blocks allocated for the payload.
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Citations
16 Claims
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1. A method for receiving multiple-input multiple-output (MIMO) transmissions, the method comprising:
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a wireless transmit/receive unit (WTRU) receiving at least one of a plurality of downlink transmissions from an eNodeB on at least one of a plurality of spatial layers, wherein the plurality of spatial layers are transmitted to a plurality of WTRUs for multi-user MIMO, and wherein the at least one spatial layer is used for reception by the WTRU; the WTRU receiving at least one WTRU-specific reference signal corresponding to the at least one downlink transmission; and the WTRU decoding the at least one downlink transmission based on the at least one corresponding WTRU-specific reference signal for the WTRU, wherein resource elements are allocated to resource blocks, and the resource blocks include WTRU-specific reference signals for the plurality of WTRUs and the downlink transmission such that WTRU-specific reference signals for different sub-groups of antenna ports are multiplexed onto different subcarriers in a frequency domain and the WTRU-specific reference signals of the same sub-group of antennas ports are each applied with a different orthogonal cover code in a time domain, wherein each sub-group of antenna ports includes at least two antenna ports, and wherein resource elements used for the downlink transmission are rate matched around resource elements allocated for the at least one WTRU-specific reference signal for the WTRU on at least one antenna port in one sub-group and are rate matched around resource elements allocated for at least one WTRU-specific reference signal for at least another WTRU on at least one antenna port in another sub-group, wherein the resource elements allocated for the at least one WTRU-specific reference signal for at least another WTRU are muted. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A wireless transmit/receive unit (WTRU) comprising:
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a transceiver configured to receive at least one of a plurality of downlink transmissions from an eNodeB on at least one of a plurality of spatial layers, wherein the plurality of spatial layers are transmitted to a plurality of WTRUs for multi-user MIMO, and wherein the at least one spatial layer is used for reception by the WTRU; the transceiver configured to receive at least one WTRU-specific reference signal corresponding to the at least one downlink transmission; and a processor operatively coupled to the transceiver, the processor configured to decode the at least one downlink transmission based on the at least one corresponding WTRU-specific reference signal for the WTRU, wherein resource elements are allocated to resource blocks, and the resource blocks include WTRU-specific reference signals for the plurality of WTRUs and the downlink transmission such that WTRU-specific reference signals for different sub-groups of antenna ports are multiplexed onto different subcarriers in a frequency domain and the WTRU-specific reference signals of the same sub-group of antennas ports are each applied with a different orthogonal cover code in a time domain, wherein resource elements used for the downlink transmission are rate matched around resource elements allocated for the at least one WTRU-specific reference signal for the WTRU on at least one antenna port in one sub-group and are rate matched around resource elements allocated for at least one WTRU-specific reference signal for at least another WTRU on at least one antenna port in another sub-group, wherein the resource elements allocated for the at least one WTRU-specific reference signal for at least another WTRU are muted. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification