DYNAMIC PRIMARY SCRAMBLING CODE DISAMBIGUATION

• US 20140287759A1
• Filed: 03/21/2013
• Published: 09/25/2014
• Est. Priority Date: 03/21/2013
• Status: Active Grant

• Current Assignee: Corning Optical Communications LLC (Corning Incorporated)
• Original Assignee: SpiderCloud Wireless, Inc. (Corning Incorporated)
• Inventors: Purohit, Darshan
• Granted Patent: US 9,642,106 B2
• Time in Patent Office: Days
• US Class Current: 455/437
• CPC Class Codes: H04W 36/00835 Determination of neighbour cell lists
• CPC Class Codes: H04W 36/0085 Hand-off measurements
• CPC Class Codes: H04W 56/0015 one node acting as a reference for the others
• CPC Class Codes: H04W 84/045 using private Base Stations, e.g. femto Base Stations, home Node B

Abstract

Systems and methods are provided for resolving Primary Scrambling Code (PSC) ambiguity. A radio link having the same PSC as that reported by user equipment (UE) may be created on some or all internal cells which are chosen based on radio frequency (RF) proximity to a serving cell of the UE or one or more iterations of a PSC resolution set selection process. If the UE is reporting the PSC of one of these cells, the UE and a Node Bs will be able to successfully complete a synchronization procedure to add one of the radio links to the UE'"'"'s active set, while any remaining created radio links can be deleted. After a certain number of successful radio link additions, the combination of the PSC and active set may be considered to be resolved, therefore, negating a need to resolve the PSC in subsequent soft handover requests.

Claims

1. A method comprising:

receiving a measurement report from user equipment (UE) including a primary scrambling code (PSC) indicative of a target cell;

creating a radio link on each of a plurality of cells, including the target cell, that are associated with the PSC;

performing a synchronization procedure to add the created radio links to the UE'"'"'s active set; and

receiving a radio link restore indication for one of the created radio links associated with the target cell.

2. The method of claim 1 further comprising, deleting the remainder of the created radio links.

3. The method of claim 1 further comprising, creating the radio link on each of the plurality of cells with the same orthogonal variable spreading factor (OVSF) code and the same timing offset information.

4. The method of claim 1, wherein the plurality of cells comprises at least a subset of internal cells.

5. The method of claim 4 further comprising, determining whether a cell belongs in the subset of internal cells by performing at least one of the following:

ignoring a cell if the cell has previously been included in the subset;

selecting the cell if the cell was detected by a serving cell of the UE;

selecting the cell by a second cell within the active set of the UE; and

selecting the cell if the cell is a strongest detected first tier neighbor cell.

6. The method of claim 1 further comprising, repeating the synchronization procedure to add the created radio links for a predetermined number of iterations.

7. The method of claim 6 further comprising, pegging the PSC with the target cell as a neighbor of the active set of the UE, and assigning a resolved status to a combination of the PSC and the active set.

8. The method of claim 7 further comprising, maintaining the combination of the PSC and the active set as an entry in a dynamically populated hash table.

9. The method of claim 6 further comprising, pegging the PSC with the target cell as a neighbor of the active set of the UE, and assigning an unresolved status to a combination of the PSC and the active set if the repeating of the synchronization procedure results in a predetermined number of failures to receive the radio link restore indication.

10. An apparatus comprising:

a processor; and

a memory including computer program code, the memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform at least the following;

receive a measurement report from user equipment (UE) including a primary scrambling code (PSC) indicative of a target cell;

create a radio link on each of a plurality of cells, including the target cell, that are associated with the PSC;

perform a synchronization procedure to add the created radio links to the UE'"'"'s active set; and

receive a radio link restore indication for one of the created radio links associated with the target cell.

11. The apparatus of claim 10, wherein the memory and the computer program code configured to, with the at least one processor, further cause the apparatus to delete the remainder of the created radio links.

12. The apparatus of claim 10, wherein the plurality of cells comprises at least a subset of internal cells.

13. The apparatus of claim 10, wherein the memory and the computer program code configured to, with the at least one processor, further cause the apparatus to repeat the synchronization procedure to add the created radio links for a predetermined number of iterations.

14. The apparatus of claim 13, wherein the memory and the computer program code configured to, with the at least one processor, further cause the apparatus to peg the PSC with the target cell as a neighbor of the active set of the UE, and assign a resolved status to a combination of the PSC and the active set.

15. A computer program product embodied on a computer-readable non-transitory medium comprising:

computer code for receiving a measurement report from user equipment (UE) including a primary scrambling code (PSC) indicative of a target cell;

computer code for creating a radio link on each of a plurality of cells, including the target cell, that are associated with the PSC;

computer code for performing a synchronization procedure to add the created radio links to the UE'"'"'s active set; and

computer code for receiving a radio link restore indication for one of the created radio links associated with the target cell