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Avoidance of service interruptions in visited public land mobile network (VPLMNs)

  • US 7,773,990 B2
  • Filed: 02/09/2006
  • Issued: 08/10/2010
  • Est. Priority Date: 05/23/2005
  • Status: Active Grant
First Claim
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1. A method in a user equipment of selecting among available public land mobile networks (PLMNs), each PLMN including at least one cell, comprising the steps of:

  • scanning for available PLMNs when the user equipment is connected to a visited public land mobile network (VPLMN);

    picking an available PLMN for evaluation;

    reading system information of at least one cell in the picked available PLMN, wherein the system information includes a minimum required quality level in the cell, a minimum required receive level in the cell, and a maximum transmit power level to access the cell on a random access channel;

    evaluating a cell selection criterion based on the read system information;

    repeating the picking, reading, and evaluating steps for remaining available PLMNs; and

    selecting an available PLMN having a highest priority and having a cell fulfilling the cell selection criterion;

    wherein the scanning step includes a step of determining a list of available PLMNs, and the evaluating step includes a step of removing a picked available PLMN from the list if the cell selection criterion is not fulfilled by the at least one cell in the picked available PLMN.

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