Efficient reselections in the presence of closed subscriber group cells

• US 8,958,794 B2
• Filed: 04/16/2013
• Issued: 02/17/2015
• Est. Priority Date: 11/04/2008
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Inventors: Narasimha, Murali, Kuchibhotla, Ravi, Krishnamurthy, Sandeep H
• Primary Examiner(s): PHAM, TIMOTHY X
• Application Number:
  US13/863,477
• Publication Number:
  US 20130231110A1
• Time in Patent Office: 672 Days
• Field of Search: 455/434
• US Class Current: 455/434
• 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 mobile station comprising:

a wireless transceiver;

the mobile station configured to detect presence of a first restricted access cell, at a first time, and to determine that the mobile station is not allowed to access the restricted access cell, the mobile station configured to determine, from information received from the first restricted access cell via the wireless transceiver, whether intra-frequency reselection is allowed, the mobile station configured to detect presence of a second restricted access cell at a second time, and the mobile station configured to save battery life of the mobile station by checking information received from the second restricted access cell via the wireless transceiver and determine again whether intra-frequency reselection is allowed only if the second time is later than the first time by more than a specified duration.

2. The mobile station of claim 1 wherein detecting the presence of a restricted access cell comprises:

detecting the presence of a cell; and

determining that an identifier of the cell belongs to a set of identifiers corresponding to identifiers of restricted access cells.

3. The mobile station of claim 2 wherein detecting the presence of a cell further comprises:

performing measurements of receive power of a signal of the cell; and

determining, based on the measurements, that the cell is a candidate for reselection.

4. The mobile station of claim 1 wherein the specified duration is defined within the information broadcasted by the second restricted access cell.

5. A method of saving battery in a wireless communication device, the method comprising:

determining that the wireless communication device is not allowed to access a first restricted access cell detected by the wireless communication device at a first time;

determining, from information received from the first restricted access cell via a wireless transceiver, whether intra-frequency reselection is allowed;

determining that the wireless communication device is not allowed to access a second restricted access cell detected by the wireless communication device at a second time, the second time later than the first time; and

checking information received from the second restricted access cell via the wireless transceiver and determining again whether intra-frequency reselection is allowed only if the second time is later than the first time by more than a specified duration.

6. The method of claim 5 wherein determining that the wireless communication device is not allowed to access a restricted access cell comprises:

detecting the presence of a cell; and

determining that an identifier of the cell belongs to a set of identifiers corresponding to identifiers of restricted access cells.

7. The method according to claim 6 wherein detecting the presence of a cell further comprises:

performing measurements of receive power of a signal of the cell; and

determining, based on the measurements, that the cell is a candidate for reselection.

8. The method of claim 5 wherein the specified duration is defined within the information broadcasted by the second restricted access cell.