Method of reselecting a cell based on priorities
A cell reselection method in a wireless communication system is described. A method of performing cell reselection based on priorities by a user equipment (UE) in a wireless communication system includes selecting one or more candidate cells satisfying a first criterion associated with priorities among a serving cell and neighbor cells, and camping on a cell satisfying a second criterion for cell reselection among the one or more candidate cells.
1. A method of performing cell reselection based on priorities by a user equipment (UE) in a wireless communication system, the method comprising the steps of:
selecting one or more candidate cells satisfying a first criterion associated with priorities among a serving cell and neighbor cells; and
camping on a cell satisfying a second criterion for cell reselection among the one or more candidate cells,
wherein the first criterion is UE-common or UE-specific, and
if there are two or more first criterions, a UE-specific first criterion has a priority over a UE-common first criterion.
2. The method of claim 1 , wherein the priorities are related to frequencies, radio access technologies (RATs), cells, or any combination thereof.
3. The method of claim 1 , wherein the priorities are UE-common or UE-specific.
4. The method of claim 1 , wherein the first criterion is a minimum priority which should be satisfied by the candidate cells.
5. The method of claim 1 , further comprising receiving the first criterion from a network.
6. The method of claim 5 , wherein the first criterion is invalidated when a certain period of time has elapsed after the reception of the first criterion, or when a region, a cell or a group to which the UE belongs has been changed.
7. The method of claim 1 , wherein the first criterion is used to distinguish between a suitable cell and an acceptable cell.
8. The method of claim 7 , wherein if no cells satisfy the first criterion, the UE transitions to ‘Any Cell Selection’ state.
9. The method of claim 7 , wherein if any cell satisfies the first criterion, the UE transitions to ‘Camped normally’ state.
10. The method of claim 1 , wherein the second criterion comprises selecting the highest priority cell among one or more cells satisfying a specific signal characteristic value.
11. The method of claim 1 , wherein the second criterion comprises selecting a cell having good signal characteristics.
12. The method of claim 11 , wherein the second criterion comprises selecting a cell having good signal characteristics using a ranking procedure.
13. The method of claim 11 , wherein if a signal characteristic value of the serving cell is equal to or more than a specific value, the selecting a cell having good signal characteristics is not performed.
14. The method of claim 1 , wherein the cell reselection comprises at least one of intra-frequency cell reselection, inter-frequency cell reselection, and inter- radio access technology (RAT) cell reselection.
15. A method of performing cell reselection based on priorities in a wireless communication system, the method comprising the steps of:
determining whether or not a serving cell satisfies a first criterion associated with priorities; and
if the serving cell satisfies the first criterion, triggering a cell reselection procedure only when a signal characteristic value of the serving cell is equal to or less than a specific value,
wherein the first criterion is UE-common or UE-specific, and
if there are two or more first criterions, a UE-specific first criterion has a priority over a UE-common first criterion.
16. The method of claim 15 , wherein the priorities are related to frequencies, radio access technologies (RATs), cells, or any combination thereof.
17. The method of claim 15 , wherein the priorities are UE-common or UE-specific.
18. The method of claim 15 , wherein the first criterion is a minimum priority which should be satisfied by the serving cell.
19. The method of claim 15 , further comprising receiving the first criterion from a network.
20. The method of claim 15 , wherein the first criterion is invalidated when a certain period of time has elapsed after the reception of the first criterion, or when a region, a cell or a group to which the UE belongs has been changed.
21. A method of transmitting control information associated with cell reselection in a wireless communication system, the method comprising the steps of:
transmitting a first message indicating information associated with priorities used during the cell reselection; and
transmitting a second message indicating a first criterion associated with priorities which should be satisfied by a serving cell and neighbor cells to be selected as a candidate cell, wherein the first criterion is UE-common or UE-specific, and if there are two or more first criterions, a UE-specific first criterion has a priority over a UE-common first criterion.
22. The method of claim 21 , wherein the priorities are related to frequencies, radio access technologies (RATs), cells, or any combination thereof.
23. The method of claim 21 , wherein the priorities are UE-common or UE-specific.
24. The method of claim 21 , wherein the information associated with priorities is a neighbor cell list (NCL).
25. The method of claim 21 , wherein the first criterion is a minimum priority which should be satisfied by the serving cell and the neighbor cells to be selected as the candidate cell.
26. The method of claim 21 , wherein the first criterion is UE-common or UE-specific.