METHOD AND APPARATUS FOR PATHLOSS DERIVATION FOR BEAM OPERATION IN A WIRELESS COMMUNICATION SYSTEM

• US 20180049137A1
• Filed: 08/10/2017
• Published: 02/15/2018
• Est. Priority Date: 08/10/2016
• Status: Active Grant

• Current Assignee: ASUSTek Computer, Inc.
• Original Assignee: ASUSTek Computer, Inc.
• Inventors: Li, Ming-Che, Lin, Ko-Chiang, Tseng, Li-Chih
• Granted Patent: US 10,602,456 B2
• Time in Patent Office: Days
• CPC Class Codes: H04B 17/309 Measuring or estimating channel quality parameters
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/242 taking into account path loss

Abstract

A method and apparatus are disclosed, from the perspective of the UE, for deriving UE transmit power. In one embodiment, the method includes the UE deriving a first pathloss value measured from a first reference signal. In addition, the method includes the UE deriving a second pathloss value measured from a second reference signal. The method also includes the UE transmitting a first UL transmission wherein the UL transmit power of the first UL transmission is derived from the first pathloss value. The method further includes the UE transmitting a second UL transmission wherein the UL transmit power of the second UL transmission is derived from the second pathloss value.

Claims

1. A method of deriving UE transmit power, comprising:

a UE derives a first pathloss value measured from a first reference signal;

the UE derives a second pathloss value measured from a second reference signal;

the UE transmits a first UL transmission wherein a UL (Uplink) transmit power of the first UL transmission is derived from the first pathloss value; and

the UE transmits a second UL transmission wherein a UL transmit power of the second UL transmission is derived from the second pathloss value.

2. The method of claim 1, wherein the first UL transmission and the second UL transmission are different types of UL transmission.

3. The method of claim 2, wherein the type of the first UL transmission is associated with at least the first reference signal for pathloss derivation, and the type of the second UL transmission is associated with at least the second reference signal for pathloss derivation.

4. The method of claim 3, wherein the association between the type of UL transmission and reference signal is specified or configured or indicated via signalling.

5. The method of claim 1, wherein the first reference signal is at least one of a reference signal for beam tracking/beam finding, a reference signal for control demodulation, a reference signal for data demodulation, a reference signal for channel measurement, or a reference signal for pathloss, and/or the second reference signal is at least one of a reference signal for beam tracking/beam finding, a reference signal for control demodulation, a reference signal for data demodulation, a reference signal for channel measurement, or a reference signal for pathloss.

6. The method of claim 5, wherein the reference signal for beam tracking/beam finding is a beam reference signal.

7. The method of claim 5, wherein the pathloss value derived from the reference signal for beam tracking/beam finding is valid until a next time beam tracking is performed.

8. The method of claim 1, wherein the pathloss value for deriving UL transmit power of the associated type of UL transmission is selected among multiple beams, and the selected pathloss value is the smallest pathloss value among the multiple beams.

9. The method of claim 5, wherein the reference signal for control demodulation is DMRS (Demodulation Reference Signal) for control.

10. The method of claim 9, wherein the pathloss value derived from the reference signal for control demodulation is valid for the UL transmission associated with the received control signalling.

11. The method of claim 5, wherein the reference signal for data demodulation is DMRS (Demodulation Reference Signal) for data.

12. The method of claim 11, wherein the pathloss value derived from the reference signal for data demodulation is valid for the UL transmission associated with the received DL (Downlink) data transmission.

13. The method of claim 12, the type of UL transmission associated with the reference signal for data demodulation comprises:

an aperiodic CSI, a periodic CSI, and/or an UL data transmission.

14. The method of claim 5, wherein the reference signal for channel measurement is CSI-RS (Channel State Information-Reference Signal).

15. The method of claim 1, wherein if UL transmit power of a UL data transmission is derived from the pathloss value derived from one associated CSI-RS (Channel State Information-Reference Signal) resource/process, the associated CSI-RS resource/process is indicated in control signaling which schedules the UL data transmission.

16. The method of claim 1, wherein if a type of UL transmission is associated with different reference signals, one reference signal of the different reference signals is determined for the pathloss value utilized for determining UL transmit power of the UL transmission.

17. The method of claim 16, wherein the pathloss value of the latest associated reference signal is utilized for determining the UL transmit power of the UL transmission.

18. The method of claim 16, wherein the valid pathloss value derived from the reference signal for data or control demodulation or the reference signal for channel measurement is utilized for determining the UL transmit power of first some types of UL transmission, instead of the valid pathloss value derived from the reference signal for beam tracking/beam finding.

19. A method of deriving UE (User Equipment) transmit power, comprising:

a UE derives a pathloss value measured from a reference signal;

the UE transmits a first UL (Uplink) transmission, wherein a UL transmit power of the first UL transmission is derived from the pathloss value and a first power offset; and

the UE transmits a second UL transmission, wherein a UL transmit power of the second UL transmission is derived from the pathloss value and a second power offset.

20. The method of claim 19, wherein for a type of UL transmission, a power offset is provided to compensate the power difference duo to difference between transmit beams of the reference signal and reception beams of the type of UL transmission.