Determining a target cell under cell identifier confusion during handovers at a base station

Patent metadata

Field	Value
Publication number	US-9949177-B2
Application number	US-201514617778-A
Country	US
Kind code	B2
Filing date	Feb 9, 2015
Priority date	Feb 9, 2015
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

The present disclosure presents a method and an apparatus for determining a target cell that is under cell identifier confusion during handovers at a small cell. For example, the disclosure presents a method that includes detecting that a target cell confusion exists at a source small cell for a target physical cell identity (PCI) during a handover of a user equipment (UE) from the source small cell to a target small cell, comparing PCI information reported by the UE during the handover with PCI information of neighbors of each of the plurality of neighboring small cells with the same PCI value, determining whether the target small cell has been identified based at least on the PCI comparison, and performing the handover of the UE from the source small cell to the target small cell. As such, a target cell may be determined.

First claim

What is claimed is:

1. A method for determining a target cell that is under physical cell identity (PCI) confusion during handovers at a small cell, comprising:
detecting, at a source small cell, that a target cell confusion exists at the source small cell for a target PCI during a handover of a user equipment (UE) from the source small cell to a target small cell, wherein the target small cell is one of a plurality of neighboring small cells with a same PCI value;
comparing, at the source small cell, PCI information reported by the UE during the handover with PCI information of neighbors of each of the plurality of neighboring small cells with the same PCI value, wherein the PCI information of neighbors of each of the plurality of neighboring small cells with the same PCI value is stored at the source small cell;
determining, at the source small cell, whether the target small cell has been identified based at least on the PCI comparison; and
in response to determining that the target small cell has not been identified;
storing reference energy patterns (REPs) of the plurality of neighboring small cells at the source small cell;
comparing reference signal (RS) energy measurements received from the UE with the REPs of the plurality of neighboring small cells with the same PCI value giving preference to a closest REP;
determining the target small cell based at least on the comparing of the RS energy measurements with the REPs; and
performing the handover of the UE from the source small cell to the determined target small cell.

2. The method of claim 1 , wherein the RS energy measurements and REPs include RS received power (RSRP) and RS received quality (RSRQ) measurements of the source small cell, the plurality of neighboring small cells, and neighbors of the plurality of neighboring small cells.

3. The method of claim 1 , further comprising:
wherein storing the REPs of the plurality of neighboring small cells at the source small cell comprises storing the REPs of the plurality of neighboring small cells with a location and a timestamp at the source small cell; and
wherein comparing the RS energy measurements received from the UE with the stored REPs of the plurality of neighboring small cells with the same PCI value giving preference to a closest REP comprises comparing the RS energy measurements received from the UE with the stored REPs of the plurality of neighboring small cells with the target PCI value giving preference to a most recent and a closest REP that is stored at the source small cell.

4. The method of claim 1 , wherein the PCI information and the REPs of each of the plurality of neighboring small cells are stored in a neighbor relation table (NRT) at the source small cells.

5. The method of claim 1 , further comprising:
receiving and storing the PCI information of neighbors of each of the plurality of neighboring small cells with the same PCI value at the source small cell.

6. The method of claim 1 , wherein a neighbor of each of the plurality of neighboring small cells is a small cell.

7. The method of claim 1 , further comprising performing the handover of the UE from the source small cell to the target small cell in response to determining that the target small cell has been identified.

8. A non-transitory computer readable medium storing computer executable code for determining a target cell that is under physical cell identity (PCI) confusion during handovers at a small cell, comprising:
code for detecting, at the source small cell, that target cell confusion exists at a source small cell for a target PCI during a handover of a user equipment (UE) from the source small cell to a target small cell, wherein the target small cell is one of a plurality of neighboring small cells with a same PCI value;
code for comparing, at the source small cell, PCI information reported by the UE during the handover with PCI information of neighbors of each of the plurality of neighboring small cells with the same PCI value, wherein the PCI information of neighbors of each of the plurality of neighboring small cells with the same PCI value is stored at the source small cell;
code for determining, at the source small cell, whether the target small cell has been identified based at least on the PCI comparison; and
code for performing operations in response to determining that the target small cell has not been identified, comprising:
code for storing reference energy patterns (REPs) of the plurality of neighboring small cells at the source small cell;
code for comparing reference signal (RS) energy measurements received from the UE with the REPs of the plurality of neighboring small cells with the same PCI value giving preference to a closest REP;
code for determining the target small cell based at least on the comparing of the RS energy measurements with the REPs; and
code for performing the handover of the UE from the source small cell to the determined target small cell.

9. The computer readable medium of claim 8 , wherein the RS energy measurements and REPs include RS received power (RSRP) and RS received quality (RSRQ) measurements of the source small cell, the plurality of neighboring small cells, and neighbors of the plurality of neighboring small cells.

10. The computer readable medium of claim 8 , further comprising:
wherein code for storing the REPs of the plurality of neighboring small cells at the source small cell comprises code for storing the REPs of the plurality of neighboring small cells with a location and a timestamp at the source small cell; and
wherein code for comparing the RS energy measurements received from the UE with the stored REPs of the plurality of neighboring small cells with the same PCI value giving preference to a closest REP that is stored at the source small cell comprises code for comparing the RS energy measurements received from the UE with the stored REPs of the plurality of neighboring small cells with the same PCI value giving preference to a most recent and a closest REP that is stored at the source small cell.

11. The computer readable medium of claim 8 , wherein the PCI information of neighbors and REPs of each of the neighboring small cells are stored in a neighbor relation table (NRT) at the source small cells.

12. The computer readable medium of claim 8 , further comprising code for performing the handover of the UE from the source small cell to the target small cell in response to determining that the target small cell has been identified.

13. An apparatus for determining a target cell that is under physical cell identity (PCI) confusion during handovers at a small cell, comprising:
a memory; and
at least one processor coupled to the memory and configured to:
detect, at the source small cell, that a target cell confusion exists at a source small cell for a target PCI during a handover of a user equipment (UE) from the source small cell to a target small cell, wherein the target small cell is one of a plurality of neighboring small cells with the same PCI value;
compare, at the source small cell, PCI information reported by the UE during the handover with PCI information of neighbors of each of the plurality of neighboring small cells with the same PCI value, wherein the PCI information of neighbors of each of the plurality of neighboring small cells with the same PCI value is stored at the source small cell;
determine, at the source small cell, whether the target small cell has been identified based at least on the PCI comparison; and
in response to determining that the target small cell has not been identified;
store reference energy patterns (REPs) of the plurality of neighboring sm

Assignees

• Qualcomm Inc

Inventors

• Sasanapuri Mohana Rao
• RAGHAVENDRA Pravin
• Vanjari Srinivas

Classifications

• H04W36/0061 Primary

  of neighbour cell information · CPC title

• H04W36/0083

  Determination of parameters used for hand-off, e.g. generation or modification of neighbour cell lists · CPC title

• H04W36/00835

  Determination of neighbour cell lists · CPC title

• H04W36/0085

  Hand-off measurements · CPC title