# US 2012/0076018 A1 · Maintaining different virtual active sets for different cell types

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- Number: US 2012/0076018 A1
- Document ID: US20120076018A1
- Status: Published application
- Kind: A1
- Application number: 13/073,049
- Filed: 2011-03-28
- Published: 2012-03-29
- Earliest claimed: 2010-03-29
- Assignees: QUALCOMM Incorporated
- Inventors: Damanjit Singh; Andrei Dragos Radulescu
- Web page: https://patentgrep.com/patent/US20120076018A1

## CPC

- H04W 36/0085: {Hand-off measurements}
- H04W 36/00835: {Determination of neighbour cell lists}
- H04W 36/00837: {Determination of triggering parameters for hand-off}
- H04W 84/045: {using private Base Stations, e.g. femto Base Stations, home Node B}
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

To facilitate inbound mobility for an access terminal, different virtual active sets are employed for different types of access points or cells (e.g., HNBs versus macro cells). In addition, different lists of permitted cells are maintained for these different types of access points or cells. Also, a frequency quality estimate for inter-frequency event triggering may be based on measurement of a single cell present in a virtual active set (e.g., a dedicated HNB virtual active set).

## Claims

### Claim 1

A method of communication, comprising:
receiving signals on a specified frequency at an access terminal; and
maintaining, based on the received signals, a virtual active set that only includes cells present in a CELL_INFO_CSG_LIST.

### Claim 2 (depends on 1)

The method of claim 1, wherein the cells present in the CELL_INFO_CSG_LIST comprise at least one of the group consisting of: closed subscriber group cells, hybrid cells, and open Home NodeBs.

### Claim 3 (depends on 1)

The method of claim 1, further comprising receiving a message for configuring the CELL_INFO_CSG_LIST, wherein the message specifies which cells are allowed to be included in the virtual active set.

### Claim 4 (depends on 1)

The method of claim 1, wherein the virtual active set is predefined to have a size of one cell.

### Claim 5 (depends on 4)

The method of claim 4, further comprising:
identifying a plurality of cells from which the received signals originated;
identifying a best cell from the plurality of cells based on a defined measurement criterion; and
including the identified best cell in the virtual active set.

### Claim 6 (depends on 5)

The method of claim 5, wherein the defined measurement criterion comprises a measurement criterion specified for a 3GPP Event 1a.

### Claim 7 (depends on 1)

The method of claim 1, further comprising:
receiving other signals on the specified frequency; and
maintaining another virtual active set for at least one other cell based on the received other signals, wherein the other virtual active set only includes cells present in a CELL_INFO_LIST.

### Claim 8 (depends on 1)

The method of claim 1, further comprising calculating a frequency quality estimate for inter-frequency event reporting based solely on a best cell of the virtual active set.

### Claim 9 (depends on 1)

The method of claim 1, wherein a weight parameter is defined for applying weighting to cell measurements for inter-frequency event reporting, the method further comprising setting the weight parameter to a defined value to cause only one cell present in the virtual active set to be used for the inter-frequency event reporting.

### Claim 10 (depends on 9)

The method of claim 9, wherein the defined value comprises a value of zero.

### Claim 11 (depends on 9)

The method of claim 9, wherein the virtual active set includes a plurality of cells, the method further comprising:
selecting a first cell of the plurality of cells as a best cell of the virtual active set;
changing the best cell of the virtual active set by selecting a second cell of the plurality of cells in place of the first cell; and
resetting a time-to-trigger parameter for the inter-frequency event reporting based on the change of the best cell.

### Claim 12 (depends on 9)

The method of claim 9, wherein the change of the best cell comprises determining whether a measured quality associated with the second cell exceeds a measured quality associated with the first cell by at least a defined amount for at least a defined period of time.

### Claim 13 (depends on 12)

The method of claim 12, wherein:
the defined amount comprises a hysteresis parameter for a 3GPP Event 1c; and
the defined period of time comprises a time-to-trigger parameter for a 3GPP Event 1c.

### Claim 14 (depends on 1)

The method of claim 1, wherein a weight parameter is defined for applying weighting to cell measurements for inter-frequency event reporting, the method further comprising setting the weight parameter to a defined value to cause more than one cell present in the virtual active set to be used for the inter-frequency event reporting.

### Claim 15 (depends on 14)

The method of claim 14, wherein the defined value comprises a non-zero value.

### Claim 16 (depends on 14)

The method of claim 14, wherein the weight parameter is set to the defined value to support soft handover operations.

### Claim 17

An apparatus for communication, comprising:
a receiver operable to receive signals on a specified frequency; and
a controller operable to maintain, based on the received signals, a virtual active set that only includes cells present in a CELL_INFO_CSG_LIST.

### Claim 18 (depends on 17)

The apparatus of claim 17, wherein the cells present in the CELL_INFO_CSG_LIST comprise at least one of the group consisting of: closed subscriber group cells, hybrid cells, and open Home NodeBs.

### Claim 19 (depends on 17)

The apparatus of claim 17, wherein the receiver is further operable to receive a message for configuring the CELL_INFO_CSG_LIST, wherein the message specifies which cells are allowed to be included in the virtual active set.

### Claim 20 (depends on 17)

The apparatus of claim 17, wherein the virtual active set is predefined to have a size of one cell.

### Claim 21 (depends on 20)

The apparatus of claim 20, wherein the controller is further operable to:
identify a plurality of cells from which the received signals originated;
identify a best cell from the plurality of cells based on a defined measurement criterion; and
include the identified best cell in the virtual active set.

### Claim 22 (depends on 21)

The apparatus of claim 21, wherein the defined measurement criterion comprises a measurement criterion specified for a 3GPP Event 1a.

### Claim 23 (depends on 17)

The apparatus of claim 17, wherein:
the receiver is further operable to receive other signals on the specified frequency;
the controller is further operable to maintain another virtual active set for at least one other cell based on the received other signals; and
the other virtual active set only includes cells present in a CELL_INFO_LIST.

### Claim 24 (depends on 17)

The apparatus of claim 17, wherein the controller is further operable to calculate a frequency quality estimate for inter-frequency event reporting based solely on a best cell of the virtual active set.

### Claim 25 (depends on 17)

The apparatus of claim 17, wherein:
a weight parameter is defined for applying weighting to cell measurements for inter-frequency event reporting; and
the controller is further operable to set the weight parameter to a defined value to cause only one cell present in the virtual active set to be used for the inter-frequency event reporting.

### Claim 26 (depends on 25)

The apparatus of claim 25, wherein the defined value comprises a value of zero.

### Claim 27 (depends on 25)

The apparatus of claim 25, wherein the virtual active set includes a plurality of cells and the controller is further operable to:
select a first cell of the plurality of cells as a best cell of the virtual active set;
change the best cell of the virtual active set by selecting a second cell of the plurality of cells in place of the first cell; and
reset a time-to-trigger parameter for the inter-frequency event reporting based on the change of the best cell.

### Claim 28 (depends on 25)

The apparatus of claim 25, wherein the change of the best cell comprises determining whether a measured quality associated with the second cell exceeds a measured quality associated with the first cell by at least a defined amount for at least a defined period of time.

### Claim 29 (depends on 28)

The apparatus of claim 28, wherein:
the defined amount comprises a hysteresis parameter for a 3GPP Event 1c; and
the defined period of time comprises a time-to-trigger parameter for a 3GPP Event 1c.

### Claim 30 (depends on 17)

The apparatus of claim 17, wherein:
a weight parameter is defined for applying weighting to cell measurements for inter-frequency event reporting; and
the controller is further operable to set the weight parameter to a defined value to cause more than one cell present in the virtual active set to be used for the inter-frequency event reporting.

### Claim 31 (depends on 30)

The apparatus of claim 30, wherein the defined value comprises a non-zero value.

### Claim 32 (depends on 30)

The apparatus of claim 30, wherein the weight parameter is set to the defined value to support soft handover operations.

### Claim 33

An apparatus for communication, comprising:
means for receiving signals on a specified frequency; and
means for maintaining, based on the received signals, a virtual active set that only includes cells present in a CELL_INFO_CSG_LIST.

### Claim 34 (depends on 33)

The apparatus of claim 33, wherein the cells present in the CELL_INFO_CSG_LIST comprise at least one of the group consisting of: closed subscriber group cells, hybrid cells, and open Home NodeBs.

### Claim 35 (depends on 33)

The apparatus of claim 33, further comprising means for receiving a message for configuring the CELL_INFO_CSG_LIST, wherein the message specifies which cells are allowed to be included in the virtual active set.

### Claim 36 (depends on 33)

The apparatus of claim 33, wherein the virtual active set is predefined to have a size of one cell.

### Claim 37 (depends on 36)

The apparatus of claim 36, further comprising:
means for identifying a plurality of cells from which the received signals originated;
means for identifying a best cell from the plurality of cells based on a defined measurement criterion; and
means for including the identified best cell in the virtual active set.

### Claim 38 (depends on 37)

The apparatus of claim 37, wherein the defined measurement criterion comprises a measurement criterion specified for a 3GPP Event 1a.

### Claim 39 (depends on 33)

The apparatus of claim 33, wherein a weight parameter is defined for applying weighting to cell measurements for inter-frequency event reporting, the apparatus further comprising means for setting the weight parameter to a defined value to cause only one cell present in the virtual active set to be used for the inter-frequency event reporting.

### Claim 40 (depends on 39)

The apparatus of claim 39, wherein the defined value comprises a value of zero.

### Claim 41 (depends on 39)

The apparatus of claim 39, wherein the virtual active set includes a plurality of cells, the apparatus further comprising:
means for selecting a first cell of the plurality of cells as a best cell of the virtual active set;
means for changing the best cell of the virtual active set by selecting a second cell of the plurality of cells in place of the first cell; and
means for resetting a time-to-trigger parameter for the inter-frequency event reporting based on the change of the best cell.

### Claim 42 (depends on 39)

The apparatus of claim 39, wherein the change of the best cell comprises determining whether a measured quality associated with the second cell exceeds a measured quality associated with the first cell by at least a defined amount for at least a defined period of time.

### Claim 43 (depends on 42)

The apparatus of claim 42, wherein:
the defined amount comprises a hysteresis parameter for a 3GPP Event 1c; and
the defined period of time comprises a time-to-trigger parameter for a 3GPP Event 1c.

### Claim 44

A computer-program product, comprising:
computer-readable medium comprising code for causing a computer to:
receive signals on a specified frequency at an access terminal; and
maintain, based on the received signals, a virtual active set that only includes cells present in a CELL_INFO CSG_LIST.

### Claim 45 (depends on 44)

The computer-program product of claim 44, wherein the cells present in a CELL_INFO_CSG_LIST comprise at least one of the group consisting of: closed subscriber group cells, hybrid cells, and open Home NodeBs.

### Claim 46 (depends on 44)

The computer-program product of claim 44, wherein the computer-readable medium further comprises code for causing the computer to receive a message for configuring the CELL_INFO_CSG_LIST, wherein the message specifies which cells are allowed to be included in the virtual active set.

### Claim 47 (depends on 44)

The computer-program product of claim 44, wherein the virtual active set is predefined to have a size of one cell.

### Claim 48 (depends on 47)

The computer-program product of claim 47, wherein the computer-readable medium further comprises code for causing the computer to:
identify a plurality of cells from which the received signals originated;
identify a best cell from the plurality of cells based on a defined measurement criterion; and
include the identified best cell in the virtual active set.

### Claim 49 (depends on 48)

The computer-program product of claim 48, wherein the defined measurement criterion comprises a measurement criterion specified for a 3GPP Event 1a.

### Claim 50 (depends on 44)

The computer-program product of claim 44, wherein:
a weight parameter is defined for applying weighting to cell measurements for inter-frequency event reporting; and
the computer-readable medium further comprises code for causing the computer to set the weight parameter to a defined value to cause only one cell present in the virtual active set to be used for the inter-frequency event reporting.

### Claim 51 (depends on 50)

The computer-program product of claim 50, wherein the defined value comprises a value of zero.

### Claim 52 (depends on 50)

The computer-program product of claim 50, wherein the virtual active set includes a plurality of cells and the computer-readable medium further comprises code for causing the computer to:
select a first cell of the plurality of cells as a best cell of the virtual active set;
change the best cell of the virtual active set by selecting a second cell of the plurality of cells in place of the first cell; and
reset a time-to-trigger parameter for the inter-frequency event reporting based on the change of the best cell.

### Claim 53 (depends on 50)

The computer-program product of claim 50, wherein the change of the best cell comprises determining whether a measured quality associated with the second cell exceeds a measured quality associated with the first cell by at least a defined amount for at least a defined period of time.

### Claim 54 (depends on 53)

The computer-program product of claim 53, wherein:
the defined amount comprises a hysteresis parameter for a 3GPP Event 1c; and
the defined period of time comprises a time-to-trigger parameter for a 3GPP Event 1c.