Power control management in uplink (UL) coordinated multipoint (CoMP) transmission

Patent metadata

Field	Value
Publication number	US-9730164-B2
Application number	US-201313752856-A
Country	US
Kind code	B2
Filing date	Jan 29, 2013
Priority date	Jan 30, 2012
Publication date	Aug 8, 2017
Grant date	Aug 8, 2017

Abstract

Techniques for performing path loss (PL) compensation in coordinated multipoint (CoMP) systems are provided. A method for wireless communications by a user equipment (UE) is provided. The method generally includes selecting, from a plurality of transmission points involved in uplink (UL) coordinated multipoint (CoMP) operations with the UE, a transmission point to associate with for path loss (PL) compensation, and adjusting power of one or more transmissions based on path loss measured based on the selected transmission point.

First claim

What is claimed is:

1. A method for wireless communications by a user equipment (UE), comprising:
selecting, from a plurality of transmission points involved in uplink (UL) coordinated multipoint (CoMP) operations with the UE, a transmission point to associate with for path loss (PL) compensation, wherein:
the plurality of transmission points comprises transmission points of different power class types forming a heterogeneous network;
the selection comprises selecting a macro transmission point if a measured PL for the macro transmission point is below a threshold value; and
the threshold value is determined based, at least in part, on a PL of a pico transmission point, a difference in a transmission power of the macro transmission point and a transmission power of the pico transmission point, and a bias amount that compensates for the difference; and

adjusting power of one or more UL transmissions based on path loss measured based on the selected transmission point.

2. A method for wireless communications by a user equipment (UE), comprising:
receiving signaling indicating a list of channel state information reference signals (CSI-RS) ports, each CSI-RS port in the list associated with a different one of a plurality of transmission points involved in uplink (UL) coordinated multipoint (CoMP) transmissions with the UE, and a corresponding transmission power for each CSI-RS port by the associated transmission point, wherein the signaling indicates disjoint sets of CSI-RS ports specified for downlink (DL) CoMP measurements and UL CoMP measurements;
measuring path loss (PL) for the plurality of transmission points, wherein the measuring comprises measuring the PL based on the CSI-RS transmitted from the plurality of transmission points using the CSI-RS port associated with each transmission point; and
selecting, based on the PL measurements, one of the transmission points for applying PL compensation.

3. The method of claim 2 , wherein the selecting comprises:
selecting a transmission point with a smallest measured path loss for applying PL compensation.

4. The method of claim 3 , wherein the measuring comprises:
measuring common reference signals (CRS) from a first cell by performing interference cancellation (IC) of CRS from at least a second cell.

5. An apparatus for wireless communications by a user equipment (UE), comprising:
means for selecting, from a plurality of transmission points involved in uplink (UL) coordinated multipoint (CoMP) operations with the UE, a transmission point to associate with for path loss (PL) compensation, wherein:
the plurality of transmission points comprises transmission points of different power class types forming a heterogeneous network;
the selection comprises selecting a macro transmission point if a measured PL for the macro transmission point is below a threshold value; and
the threshold value is determined based, at least in part, on a PL of a pico transmission point, a difference in a transmission power of the macro transmission point and a transmission power of the pico transmission point, and a bias amount that compensates for the difference; and

means for adjusting power of one or more UL transmissions based on path loss measured based on the selected transmission point.

6. An apparatus for wireless communications by a user equipment (UE), comprising:
means for receiving signaling indicating a list of channel state information reference signals (CSI-RS) ports, each CSI-RS port in the list associated with a different one of a plurality of transmission points involved in uplink (UL) coordinated multipoint (CoMP) transmissions with the UE, and a corresponding transmission power for each CSI-RS port by the associated transmission point, wherein the signaling indicates disjoint sets of CSI-RS ports specified for downlink (DL) CoMP measurements and UL CoMP measurements;
means for measuring path loss (PL) for the plurality of transmission points, wherein the measuring comprises measuring the PL based on the CSI-RS transmitted from the plurality of transmission points using the CSI-RS port associated with each transmission point; and
means for selecting, based on the PL measurements, one of the transmission points for applying PL compensation.

7. An apparatus for wireless communications by a user equipment (UE), comprising:
at least one processor configured to:
select, from a plurality of transmission points involved in uplink (UL) coordinated multipoint (CoMP) operations with a UE, a transmission point to associate with for path loss (PL) compensation, wherein:
the plurality of transmission points comprises transmission points of different power class types forming a heterogeneous network;
the selection comprises selecting a macro transmission point if a measured PL for the macro transmission point is below a threshold value; and
the threshold value is determined based, at least in part, on a PL of a pico transmission point, a difference in a transmission power of the macro transmission point and a transmission power of the pico transmission point, and a bias amount that compensates for the difference; and

adjust power of one or more UL transmissions based on path loss measured based on the selected transmission point; and

a memory coupled with the at least one processor.

8. An apparatus for wireless communications by a user equipment (UE), comprising:
at least one processor configured to:
receive signaling indicating a list of channel state information reference signals (CSI-RS) ports, each CSI-RS port in the list associated with a different one of a plurality of transmission points involved in uplink (UL) coordinated multipoint (CoMP) transmissions with the UE, and a corresponding transmission power for each CSI-RS port by the associated transmission point, wherein the signaling indicates disjoint sets of CSI-RS ports specified for downlink (DL) CoMP measurements and UL CoMP measurements;
measure path loss (PL) for the plurality of transmission points, wherein the measuring comprises measuring the PL based on the CSI-RS transmitted from the plurality of transmission points using the CSI-RS port associated with each transmission point; and
select, based on the PL measurements, one of the transmission points for applying PL compensation; and

a memory coupled with the at least one processor.

9. A non-transitory computer readable medium having instructions stored thereon, the instructions generally executable by one or more processors for wireless communications by a user equipment (UE), the instructions comprising instructions for:
selecting, from a plurality of transmission points involved in uplink (UL) coordinated multipoint (CoMP) operations with a UE, a transmission point to associate with for path loss (PL) compensation, wherein:
the plurality of transmission points comprises transmission points of different power class types forming a heterogeneous network;
the selection comprises selecting a macro transmission point if a measured PL for the macro transmission point is below a threshold value; and
the threshold value is determined based, at least in part, on a PL of a pico transmission point, a difference in a transmission power of the macro transmission point and a transmission power of the pico transmission point, and a bias amount that compensates for the difference; and

adjusting power of one or more UL transmissions based on path loss measured based on the selected transmission point.

10. A non-transitory computer readable medium having instructions stored thereon, the instructions generally executable by one or more processors for wireless communications by a user equipment (UE), the instructions comprising instructions for:

Assignees

• Qualcomm Inc
• Qualcomm Inc

Inventors

• Xu Hao
• Gaal Peter
• Chen Wanshi
• Geirhofer Stefan
• Vajapeyam Madhavan Srinivasan

Classifications

• H04L5/0035

  Resource allocation in a cooperative multipoint environment · CPC title

• H04L5/0073

  Allocation arrangements that take into account other cell interferences · CPC title

• H04W52/50

  at the moment of starting communication in a multiple access environment · CPC title

• H04L5/0048

  Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091) · CPC title

• H04W52/325

  Power control of control or pilot channels · CPC title