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

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 small cells at the source small cell;

compare 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;

determine the target small cell based at least on the comparing of the RS energy measurements with the REPs; and

perform the handover of the UE from the source small cell to the determined target small cell.

14. The apparatus of claim 13 , 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.

15. The apparatus of claim 13 , wherein the at least one processor is further configured to:

store the REPs of the plurality of neighboring small cells at the source small cell comprises by storing the REPs of the neighboring small cells with a location and a timestamp at the source small cell; and

compare 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 by 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.

16. The apparatus of claim 13 , wherein the PCI information and REPs of each of the plurality of neighboring small cells are stored in a neighbor relation table (NRT) at the source small cells.

17. The apparatus of claim 13 , wherein the at least one processor is further configured to perform 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.