Beamforming in tdd mimo systems with asymmetric antenna configuration
AssigneeQUALCOMM Incorporated
InventorsXiaoxia Zhang, Wei Zhang
Life of this patent
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Abstract
Beamforming in time division duplex (TDD) multiple input, multiple output (MIMO) systems is discussed involving user equipments (UEs) having asymmetric antenna configurations. Aspects of the present disclosure use different combinations of signaling overhead and feedback along with leveraging the channel reciprocity characteristics of TDD systems in order to determine channel estimates for determining beamforming vectors. Additional aspects determine scheduling between UEs with symmetric receiver/transmission chains and asymmetric receiver/transmission chains to optimize reference signal overhead for groups of UEs with common beamforming processes.
Claims30
A method of wireless communication in a time division duplex (TDD) multiple input, multiple output (MIMO) system, comprising:
- receiving an uplink reference signal from a served user equipment (UE) on each channel corresponding to one or more transmit antennas of the served UE, wherein the one or more transmit antennas are fewer than a plurality of receive antennas of the served UE;
- calculating a downlink channel estimate based on the uplink reference signal;
- receiving an interference report from the served UE, wherein the interference report identifies an interference level associated with one or more receive antennas with transmission capability;
- selecting a precoder based on the received interference report and the downlink channel estimate;
- and
- beamforming data using the selected precoder.
An apparatus configured for wireless communication, the apparatus comprising:
- at least one processor;
- and
- a memory coupled to the at least one processor,
- wherein the at least one processor is configured:
- to receive an uplink reference signal from a served user equipment (UE) on each channel corresponding to one or more transmit antennas of the served UE in a time division duplex (TDD) multiple input, multiple output (MIMO) system, wherein the one or more transmit antennas are fewer than a plurality of receive antennas of the served UE;
- to calculate a downlink channel estimate based on the uplink reference signal;
- to receive an interference report from the served UE, wherein the interference report identifies an interference level associated with one or more receive antennas with transmission capability;
- to select a precoder based on the received interference report and the downlink channel estimate;
- and
- to beamform data using the selected precoder.
A method of wireless communication in a time division duplex (TDD) multiple input, multiple output (MIMO) system, comprising:
- transmitting, by a user equipment (UE), an uplink reference signal to a serving base station on each channel corresponding to one or more transmit antennas of the UE, wherein the one or more transmit antennas are fewer than a plurality of receive antennas of the UE;
- transmitting, by the UE, an interference report to the serving base station, wherein the interference report identifies an interference level associated with one or more receive antennas with transmission capability;
- and
- receiving, by the UE, beamformed data, wherein the beamformed data is beamformed using a precoder, wherein the precoder is selected based on the transmitted interference report and a downlink channel estimate calculated based on the transmitted uplink reference signal.
An apparatus configured for wireless communication, the apparatus comprising:
- at least one processor, and
- a memory coupled to the at least one processor,
- wherein the at least one processor is configured:
- to transmit, by a user equipment (UE), an uplink reference signal to a serving base station on each channel corresponding to one or more transmit antennas of the UE, wherein the one or more transmit antennas are fewer than a plurality of receive antennas of the UE;
- to transmit, by the UE, an interference report to the serving base station, wherein the interference report identifies an interference level associated with one or more receive antennas with transmission capability;
- and
- to receive, by the UE, beamformed data, wherein the beamformed data is beamformed using a precoder, wherein the precoder is selected based on the transmitted interference report and a downlink channel estimate calculated based on the transmitted uplink reference signal.
Dependencies are inferred from the claim text.