Efficient Reselections in the Presence of Closed Subscriber Group Cells

• US 20100113026A1
• Filed: 10/26/2009
• Published: 05/06/2010
• Est. Priority Date: 11/04/2008
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Narasimha, Murali, Kuchibhotla, Ravi, Krishnamurthy, Sandeep H.
• Granted Patent: US 8,504,039 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04W 36/0079 in case of hand-off failure or rejection
• CPC Class Codes: H04W 36/04 Reselecting a cell layer in multi-layered cells
• CPC Class Codes: H04W 36/20 for optimising the interference level
• CPC Class Codes: H04W 48/02 Access restriction performed under specific conditions
• CPC Class Codes: H04W 48/18 Selecting a network or a communication service
• CPC Class Codes: H04W 72/02 Selection of wireless resources by user or terminal

Abstract

A method in a mobile station for avoiding interference to restricted access cells, including detecting presence of a restricted access cell, determining that a measured path-loss is larger than a path-loss threshold, determining that the mobile station is not allowed to access the restricted access cell, and barring a carrier frequency on which the restricted access cell is deployed when the measured path-loss is larger than the path-loss threshold and when the mobile station is not allowed access to the restricted access cell.

Claims

1. A method in a mobile station for avoiding interference to restricted access cells, the method comprising:

detecting presence of a restricted access cell;

determining that a measured path-loss is larger than a path-loss threshold;

determining that the mobile station is not allowed to access the restricted access cell; and

barring a carrier frequency on which the restricted access cell is deployed when the measured path-loss is larger than the path-loss threshold and when the mobile station is not allowed access to the restricted access cell.

2. The method according to claim 1, receiving the path-loss threshold from a first base station.

3. The method according to claim 1 further comprising

determining that the measured path-loss from the first base station is not larger than the path-loss threshold, and

continuing operating on the carrier frequency on which the restricted access cell is deployed when the measured path-loss is not larger than the path-loss threshold.

4. The method according to claim 1, determine the measured path-loss based on a signal from a base station, wherein the base station and the restricted access cell share the carrier frequency.

5. The method according to claim 1 further comprising

receiving from the restricted access cell an indication that intra-frequency reselection is not allowed,

barring the carrier frequency on which the restricted access cell is deployed when all of the following conditions are satisfied:

the measured path-loss is larger than the path-loss threshold,

the mobile station is not allowed access to the restricted access cell, and

an indication that intra-frequency reselection is not allowed is received.

6. The method according to claim 1 further comprising receiving from the restricted access cell an indication that intra-frequency reselection is allowed, and

operating on the carrier frequency on which the restricted access cell is deployed when any one of the following conditions is satisfied:

the measured path-loss is not larger than the path-loss threshold,

the mobile station is allowed access to the restricted access cell,

an indication that intra-frequency reselection is allowed is received.

7. The method according to claim 1, determine the measured path-loss, wherein the measured path-loss is a transmit power of a base station signal minus a received power of the base station signal.

8. A method in a base station for avoiding interference to restricted access cells, the method comprising:

determining that restricted access cells are present in a coverage area of the base station, and

transmitting a path-loss threshold.

9. A method in a wireless communication device comprising:

receiving signals from at least a first base station;

receiving at least a path-loss threshold from the first base station;

measuring path-loss from a serving base station;

determining whether the wireless communication device is allowed to access a restricted access cell detected by the device;

determining whether the wireless communication device is required to reselect to a different frequency or radio access technology;

reselecting to a different frequency or radio access technology in response to determining that the wireless communication device is not allowed to access the restricted access cell and that the measured path-loss from the serving base station is equal to or greater than the path-loss threshold.

10. The method according to claim 9, further comprising determining that the wireless communication device is not required to reselect to a different frequency or radio access technology in response to determining that the wireless communication device is not allowed to access the restricted access cell and that the measured path-loss from the serving base station is less than the path-loss threshold.

11. The method according to claim 9

receiving from the restricted access cell an indication of whether intra-frequency reselection is allowed;

and

determining that the wireless communication device is required to reselect to a different frequency or radio access technology in response to determining that the wireless communication device is not allowed to access the restricted access cell, that the measured path-loss from the serving base station is equal to or greater than the path-loss threshold, and receiving an indication from the restricted access cell that intra-frequency reselection is not allowed.

12. The method according to claim 9 determining that the wireless communication device is not required to reselect to a different frequency or radio access technology in response to determining that the wireless communication device is not allowed to access the restricted access cell and that the measured path-loss from the serving base station is equal to or greater than the path-loss threshold, and receiving an indication from the restricted access cell that intra-frequency reselection is allowed.