Cell reselection enhancement for power saving LTE devices
A method of cell reselection enhancement is proposed. A UE obtains parameters for extended cell reselection (ECR) in a mobile communication network. The UE goes to sleep and then wakes up periodically to monitor a paging channel. The UE either applies a normal paging cycle having a normal paging cycle length or applies a power-saving paging cycle having a very long paging cycle length. The UE performs cell selection if normal paging cycle is applied. The UE performs cell reselection based on the ECR parameters if the power-saving paging cycle is applied, and if the ECR parameters are still valid based on a list of conditions. In one novel aspect, the network provides the ECR parameters for a wider area for the UE such that the UE can still use cell reselection after waking up from a very long sleep to reduce power consumption.
1. A method, comprising:
obtaining parameters for extended cell reselection (ECR) by a user equipment (UE) in a mobile communication network;
going to sleep and waking up periodically to monitor a paging channel, wherein the UE applies a normal paging cycle or a power-saving paging cycle;
performing cell selection if the UE applies the normal paging cycle; and
performing cell reselection based on the ECR parameters if the UE applies the power-saving paging cycle and if the ECR parameters are valid based on a list of conditions.
2. The method of claim 1 , wherein the UE performs full scanning for cell selection, and wherein the UE performs partial scanning for cell reselection.
3. The method of claim 1 , wherein the ECR parameters comprise at least one of absolute priorities of different frequencies or inter-RAT frequencies, RAT offset, threshold for reselection, timer for reselection, stop-Measure criterion, maximum transmit power, and a black/white cell list.
4. The method of claim 3 , wherein the ECR parameters further comprises the list of conditions.
5. The method of claim 1 , wherein the ECR parameters are obtained from dedicated signaling, from broadcasted system information, from another RAT, or from higher layer (NAS/MME or OMA DM).
6. The method of claim 1 , wherein the list of conditions comprises at least one of a list of cell IDs that associates with a geographic area, a tracking area, a PLMN, a timer, a cell change count, a distance, and a physical location, and wherein the ECR parameters are valid as long as one of the list of conditions is satisfied.
7. The method of claim 1 , wherein the list of conditions is predefined.
8. The method of claim 1 , wherein the UE obtains the list of conditions as part of the ECR parameters.
9. The method of claim 1 , wherein the UE deletes the ECR parameters if the ECR parameters are no longer valid based on the conditions.
10. The method of claim 1 , wherein the UE obtains updated ECR parameters if the ECR parameters are no longer valid based on the conditions.
11. A user equipment (UE), comprising:
a configuration module that obtains parameters for extended cell reselection (ECR) by a user equipment (UE) in a mobile communication network;
a sleep-mode control module for UE to go to sleep and wake up periodically to monitor a paging channel, wherein the UE applies a normal paging cycle or a power-saving paging cycle;
a cell selection module that performs cell selection if the UE applies the normal paging cycle; and
a cell reselection module that performs cell reselection based on the ECR parameters if the UE applies the power-saving paging cycle and if the ECR parameters are valid based on a list of conditions.
12. The UE of claim 11 , wherein the UE performs full scanning for cell selection, and wherein the UE performs partial scanning for cell reselection.
13. The UE of claim 11 , wherein the ECR parameters comprise at least one of absolute priorities of different frequencies or inter-RAT frequencies, RAT offset, threshold for reselection, timer for reselection, stop-Measure criterion, maximum transmit power, and a black/white cell list.
14. The UE of claim 13 , wherein the ECR parameters further comprises the list of conditions.
15. The UE of claim 11 , wherein the ECR parameters are obtained from dedicated signaling, from broadcasted system information, from another RAT, or from higher layer (NAS/MME or OMA DM).
16. The UE of claim 11 , wherein the list of conditions comprises at least one of a list of cell IDs that associates with a geographic area, a tracking area, a PLMN, a timer, a cell change count, a distance, and a physical location, and wherein the ECR parameters are valid as long as one of the list of conditions is satisfied.
17. The UE of claim 11 , wherein the list of conditions is predefined.
18. The UE of claim 11 , wherein the UE obtains the list of conditions as part of the ECR parameters.
19. The UE of claim 11 , wherein the UE deletes the ECR parameters if the ECR parameters are no longer valid based on the conditions.
20. The UE of claim 11 , wherein the UE obtains updated ECR parameters if the ECR parameters are no longer valid based on the conditions.