Method and apparatus for channel state information feedback in a coordinated multi-point communication system
A method of operating a wireless communication system (FIG. 4 ) is disclosed. The method includes receiving a plurality of reference signals from a respective plurality of transceivers ( 402 ). Each of the plurality of reference signals is measured to produce a respective plurality of channel state information (CSI) measurements ( 404 ). An aggregated channel quality indicator (CQI) is calculated from measuring the plurality of reference signals ( 406 ). The aggregated CQI is transmitted to at least one transceiver of the respective plurality of transceivers ( 408 ).
1. A method of operating a user equipment (UE), comprising the steps of:
receiving at the UE a plurality of reference signals from a respective plurality base stations;
measuring at the UE each of the plurality of reference signals to generate a respective plurality of per-point channel state information (CSI); and
transmitting the plurality of per-point CSI from the UE to at least one of the plurality of base stations.
2. The method of claim 1 , wherein the at least one of the plurality of base stations is a subset of the plurality of base stations.
3. The method of claim 1 , wherein the at least one of the plurality of base stations is all of the respective plurality of base stations.
4. The method of claim 1 , wherein the per-point CST comprises a per-point precoding matrix indicator (PMI).
5. The method of claim 4 , wherein the per-point CSI comprises a per-point channel quality indicator (CQI), and wherein the per-point CQI is derived under a hypothesis of single-point multiple-input multiple output (MIMO) beamforming on a transceiver of the respective plurality of base stations using a precoding matrix indicted by the respective per-point PMI.
6. The method of claim 4 , wherein the per-point CSI comprises a per-point co-phasing factor.
7. The method of claim 1 , wherein an effective aggregated channel composed of the channels corresponding to the respective plurality of base stations is derived under a hypothesis of the respective plurality of base stations jointly transmitting to a user equipment (UE).
8. The method of claim 1 , wherein the base stations are macro eNBs, picas eNBs, femto eNBs, or a combination thereof.
9. A user equipment (UE), comprising:
circuitry for receiving a plurality of reference signals from a respective plurality of base stations;
circuitry for measuring each of the plurality of reference signals to generate a respective plurality of per-point channel state information (CSI); and
circuitry for transmitting the plurality of per-point CSI to at least one of the plurality of base stations.
10. The user equipment (UE) of claim 9 , wherein the at least one of the plurality of base stations is a subset of the plurality of base stations.
11. The user equipment (UE) of claim 9 , wherein the at least one of the plurality of base stations is all of the respective plurality of base stations.
12. The user equipment (UE) of claim 9 , wherein the per-point CSI comprises a per-point precoding matrix indicator (PMI).
13. The user equipment (UE) of claim 9 , wherein the per-point CSI comprises a per-point channel quality indicator (CQI), and wherein the per-point CQI is derived under a hypothesis of single-point multiple-input multiple-output (MIMO) beamforming on a transceiver of the respective plurality of base stations using a precoding matrix indicted by the respective per-point PMI.
14. The user equipment (UE) of claim 9 , wherein the per-point CSI comprises a per-point co-phasing factor.
15. The user equipment (UE) of claim 9 , wherein an effective aggregated channel composed of the channels corresponding to the respective plurality of base stations is derived under a hypothesis of the respective plurality of base stations jointly transmitting to a user equipment (UE).
16. The user equipment (UE) of claim 9 , wherein the base stations are macro eNBs, pico eNBs, femto eNBs, or a combination thereof.
17. A method of operating a wireless transceiver, comprising the steps of:
transmitting a first reference signal from the wireless transceiver to a user equipment (UE);
receiving at the wireless transceiver from the UE a per-point channel state information (CSI) associated with the first reference signal and another per-point channel state information (CSI) associated with another reference signal associated with another wireless transceiver; and
transmitting communication parameters from the wireless transceiver to the UE in response to the received per-point channel state information (CSI) associated with the first and second reference signals.
18. A method as in claim 17 , comprising receiving a precoded matrix indicator (PMI) from the UE in response to the first reference signal.
19. A wireless transceiver, comprising:
circuitry for transmitting a first reference signal to a user equipment (UE);
circuitry for receiving from the UE a per-point channel state information (CSI) associated with the first reference signal and another per-point channel state information (CSI) associated with another reference signal associated with another wireless transceiver; and
circuitry for transmitting communication parameters to the UE in response to the received per-point channel state information (CSI) associated with the first and second reference signals.
20. The wireless transceiver of claim 19 , comprising circuitry for receiving a preceded matrix indicator (PMI) from the UE in response to the first reference signal.