Method, apparatus and system for mobility enhancement in DRX

• US 8,688,119 B2
• Filed: 04/30/2010
• Issued: 04/01/2014
• Est. Priority Date: 04/30/2010
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Sgfors, Mats, Wager, Stefan
• Primary Examiner(s): Gonzalez, Amancio
• Application Number:
  US12/771,799
• Publication Number:
  US 20110269462A1
• Time in Patent Office: 1,432 Days
• Field of Search: 455436-444, 370/331
• US Class Current: 455/436
• CPC Class Codes: H04W 36/0033 with transfer of context information
• CPC Class Codes: H04W 36/0085 Hand-off measurements
• CPC Class Codes: H04W 36/0094 Definition of hand-off measurement parameters
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/36 by user or terminal equipment
• CPC Class Codes: H04W 36/38 by fixed network equipment
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

When a user equipment (UE) is in a CONNECTED state with a base station of a wireless network and is also in a discontinuous reception (DRX) mode, a DRX parameter such as DRX period for the UE is compared with a threshold. If the DRX parameter is at or below the threshold, the UE applies a network controlled mobility mode with UE assist where the network controls handover of the UE to another cell. If the DRX parameter is above the threshold, the UE applies a UE controlled mobility mode in which the UE is free to select a best cell. In this way, DRX benefit of reduced power consumption is maintained while the time period in which the UE is unreachable is minimized.

Claims

1. A method of operating a user equipment (UE) for communicating with a wireless network, the method comprising:

the UE determining whether a DRX parameter of the UE is at or below a DRX threshold, the UE being in a CONNECTED state with a base station of the wireless network and operating in a discontinuous reception (DRX) mode;

the UE applying a network controlled mobility mode when the DRX parameter is at or below the DRX threshold; and

the UE applying a UE controlled mobility mode when the DRX parameter is above the DRX threshold, wherein

when the network controlled mobility mode is applied, the network controls a handover of the UE from one cell to another, and

when the UE controlled mobility mode is applied, the UE is allowed to autonomously perform a cell reselection.

2. The method according to claim 1, wherein the DRX parameter is any combination of a DRX period, a DRX inactive part, and a time since scheduling of last activity of the UE.

3. The method according to claim 1, further comprising the UE adjusting the DRX parameter based on an activity level of the UE.

4. The method according to claim 3, wherein the UE lengthens a DRX period when scheduling information from the base station indicates that no resources are scheduled for the UE, and shortens the DRX period when the scheduling information indicates that there are resources scheduled for the UE.

5. The method according to claim 1, wherein when the UE controlled mobility mode is applied, the UE reselects a cell among a set of identified cells.

6. The method according to claim 5, wherein the set of identified cells is identified by the UE through measuring radio signals of a serving cell and of neighboring cells, or is a set of neighboring cells received from the base station, or both.

7. The method according to claim 5, wherein the UE updates the network in an update message after the cell reselection, the update message being either a cell update message or a connection reestablishment request message.

8. The method according to claim 7, wherein the update message comprises an indication that the update message is sent due to the UE performing the cell reselection while the UE is in the CONNECTED state and in the UE controlled mobility mode.

9. The method according to claim 7, wherein the update message comprises prior connection information of the UE comprising any one or more of a C-RNTI of the UE, a cell ID of a previous serving cell, and a base station ID of the previous serving cell.

10. A method of operating a user equipment (UE) for communicating with a wireless network, the method comprising:

the UE determining whether a DRX parameter of the UE is at or below a DRX threshold the UE being in a CONNECTED state with a base station of the wireless network and operating in a discontinuous reception (DRX) mode;

the UE implementing a first measurement configuration of providing measurement reports of neighboring cells to the base station when the DRX parameter is at or below the DRX threshold; and

the UE implementing a second measurement configuration, of providing less frequent measurement reports of the neighboring cells to the base station relative to the first measurement configuration or no measurement reports when the DRX parameter is above the DRX threshold.

11. The method according to claim 10, wherein the DRX parameter is any combination of a DRX period, a DRX inactive part, and a time since scheduling of last activity of the UE.

12. A user equipment (UE) for communicating with a wireless network, the UE comprising:

a processing unit arranged to perform processing to operate the UE to provide communication services to a user;

a communication unit arranged to communicate with the wireless network, the communication unit comprising one or more wireless receivers which can be turned on and off;

a storage unit arranged to store information necessary for operation of the UE and arranged to store code for the processing unit to execute; and

a measurement unit arranged to measure parameters related to radio signals, wherein

the processing unit controls the communication unit, the storage unit, and the measurement unit to provide the communication services to the user, and

when the UE is in a CONNECTED state with a base station of the wireless network and is operating in a discontinuous reception (DRX) mode, the processing unit is arranged to;

determine whether a DRX parameter of the UE is at or below a DRX threshold,

when the DRX parameter is at or below the DRX threshold, apply a network controlled mobility mode in which the network controls a handover of the UE from one cell to another, and

when the DRX parameter is above the DRX threshold, apply a UE controlled mobility mode in which the UE is allowed to autonomously perform a cell reselection.

13. The UE according to claim 12, wherein the DRX parameter is any combination of a DRX period, a DRX inactive part, and a time since scheduling of last activity of the UE.

14. The UE according to claim 12, wherein the processing unit is arranged to adjust the DRX parameter based on an activity level of the UE.

15. The UE according to claim 14, wherein the processing unit lengthens a DRX period when scheduling information from the base station indicates that no resources are scheduled for the UE, and shortens the DRX period when the scheduling information indicates that there are resources scheduled for the UE.

16. The UE according to claim 12, wherein when the UE controlled mobility mode is applied, the processing unit reselects a cell among a set of identified cells.

17. The UE according to claim 16, wherein the set of identified cells are identified by the processing unit based on measurements of radio signals of a serving cell and of neighboring cells performed by the measurement unit, or are a set of neighboring cells received by the communication unit from the base station, or both.

18. The UE according to claim 16, wherein the processing unit updates the network in an update message via the communication unit, the update message being either a cell update message or a connection reestablishment request message.

19. The UE according to claim 18, wherein the update message comprises an indication that the update message is sent due to the UE performing the cell reselection while the UE is in the CONNECTED state and in the UE controlled mobility mode.

20. The UE according to claim 18, wherein the update message comprises prior connection information of the UE comprising any one or more of a C-RNTI of the UE, a cell ID of a previous serving cell, and a base station ID of the previous serving cell.

21. A user equipment (UE) for communicating with a wireless network, the UE comprising:

a processing unit arranged perform processing to operate the UE to provide communication services to a user;

a communication unit arranged to communicate with the wireless network, the communication unit comprising one or more wireless receivers which can be turned on and off;

a storage unit arranged to store information necessary for operation of the UE and arranged to store code for the processing unit to execute; and

a measurement unit arranged to measure parameters related to radio signals, wherein

the processing unit controls the communication unit, the storage unit, and the measurement unit to provide the communication services to the user, and

when the UE is in a CONNECTED state with a base station of the wireless network and is operating in a discontinuous reception (DRX) mode, the processing unit is arranged to;

determine whether a DRX parameter of the UE is at or below a DRX threshold,

implement a first measurement configuration of providing measurement reports of neighboring cells to the base station when the DRX parameter is at or below the DRX threshold, and

implement a second measurement configuration, of providing less frequent measurement reports of the neighboring cells to the base station relative to the first measurement configuration or no measurement reports when the DRX parameter is above the DRX threshold.

24. The UE according to claim 21, wherein the DRX parameter is any combination of a DRX period, a DRX inactive part, and a time since scheduling of last activity of the UE.

22. A method of operating a user equipment (UE) for communicating with a wireless network, the method comprising:

the UE determining whether a DRX parameter of the UE is at or below a DRX threshold when the UE is in a CONNECTED state with a base station of the wireless network and is operating in a discontinuous reception (DRX) mode;

the UE applying a network controlled mobility mode when the DRX parameter is at or below the DRX threshold;

the UE determining whether the UE is moving away from the base station;

the UE applying the network controlled mobility mode the UE is not moving away from the base station; and

the UE applying a UE controlled mobility mode when the DRX parameter is above the DRX threshold and the UE is moving away from the base station,

wherein when the network controlled mobility mode is applied, the network controls a handover of the UE from one cell to another, and

wherein when the UE controlled mobility mode is applied, the UE is allowed to autonomously perform a cell reselection.

23. A user equipment (UE) for communicating with a wireless network, the UE comprising:

a communication unit arranged to communicate with the wireless network;

a storage unit arranged to store information necessary for operation of the UE; and

a processing unit arranged control the communication unit and the storage unit to provide the communication services to a user,

wherein when the UE is in a CONNECTED state with a base station of the wireless network and is operating in a discontinuous reception (DRX) mode, the processing unit is arranged to;

determine whether a DRX parameter of the UE is at or below a DRX threshold,

apply a network controlled mobility mode when the DRX parameter is at or below the DRX threshold,

determine whether the UE is moving away from the base station,

apply the network controlled mobility mode the UE is not moving away from the base station, and

apply a UE controlled mobility mode when the DRX parameter is above the DRX threshold and the UE is moving away from the base station,

wherein when the network controlled mobility mode is applied, the network controls a handover of the UE from one cell to another, and

wherein when the UE controlled mobility mode is applied, the UE is allowed to autonomously perform a cell reselection.