Method and apparatus for cell reselection in wireless communication system

A wireless device in a wireless communication system comprising:

• a transceiver;
• a memory;
• and
• at least one processor operatively coupled to the transceiver and the memory,
• wherein the memory stores instructions that, based on being executed by the at least one processor, perform operations comprising:
• performing a cell reselection to a cell;
• receiving information for a plurality of signal quality ranges, information for a plurality of scaling factors each of which is mapped to the plurality of signal quality ranges, and information for a time period for determining a number of cell reselections;
• measuring a first signal quality for the cell;
• identifying, among the plurality of signal quality ranges a first signal quality range to which the first signal quality belongs;
• identifying, among the plurality of scaling factors, a first scaling factor mapped to the identified first signal quality range;
• applying the first scaling factor for the first signal quality range to the time period;
• estimating a mobility state of the wireless device based on the time period to which the first scaling factor is applied;
• and
• after estimating the mobility state of the wireless device:
• measuring a second signal quality for the cell;
• identifying, among the plurality of signal quality ranges, a second signal quality range to which the second signal quality belongs;
• identifying, among the plurality of scaling factors, a second scaling factor mapped to the second signal quality range;
• and
• applying the second scaling factor to the time period to which the first scaling factor is not applied,
• wherein the mobility state of the wireless device is determined based on the number of cell reselections,
• wherein the mobility state is determined to be a normal mobility state based on the number of cell reselections being less that a first threshold,
• wherein the mobility state is determined to be a medium mobility state based on the number of cell reselections being greater than or equal to the first threshold and less than a second threshold,
• wherein the mobility state is determined to be a high mobility state based on the number of cell reselections being greater than or equal to the second threshold,
• wherein information for the first threshold and information for the second threshold are received from a base station related to the cell, and
• wherein a hysteresis value and a cell reselection timer value for cell reselection ranking criterion are determined based on the mobility state of the wireless device.

A non-transitory computer-readable medium having recorded thereon a program for performing a method performed by a wireless device on a computer, the method comprising:

• performing a cell reselection to a cell;
• receiving information for a plurality of signal quality ranges, information for a plurality of scaling factors each of which is mapped to the plurality of signal quality ranges, and information for a time period for determining a number of cell reselections;
• measuring a first signal quality for the cell;
• identifying, among the plurality of signal quality ranges, a first signal quality range to which the first signal quality belongs;
• identifying, among the plurality of scaling factors, a first scaling factor mapped to the identified first signal quality range;
• applying the first scaling factor for the first signal quality range to the time period;
• estimating a mobility state of the wireless device based on the time period to which the first scaling factor is applied;
• and
• after estimating the mobility state of the wireless device:
• measuring a second signal quality for the cell;
• identifying, among the plurality of signal quality ranges, a second signal quality range to which the second signal quality belongs;
• identifying, among the plurality of scaling factors, a second scaling factor mapped to the second signal quality range;
• and
• applying the second scaling factor to the time period to which the first scaling factor is not applied,
• wherein the mobility state of the wireless device is determined based on the number of cell reselections,
• wherein the mobility state is determined to be a normal mobility state based on the number of cell reselections being less that a first threshold,
• wherein the mobility state is determined to be a medium mobility state based on the number of cell reselections being greater than or equal to the first threshold and less than a second threshold,
• wherein the mobility state is determined to be a high mobility state based on the number of cell reselections being greater than or equal to the second threshold,
• wherein information for the first threshold and information for the second threshold are received from a base station related to the cell, and
• wherein a hysteresis value and a cell reselection timer value for cell reselection ranking criterion are determined based on the mobility state of the wireless device.