Paging in heterogeneous networks with discontinuous reception

• US 8,964,672 B2
• Filed: 07/10/2012
• Issued: 02/24/2015
• Est. Priority Date: 11/04/2011
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Blackberry Limited
• Inventors: Suzuki, Takashi, Cai, Zhijun
• Primary Examiner(s): Ghowrwal, Omar
• Assistant Examiner(s): ONAMUTI, GBEMILEKE J
• Application Number:
  US13/545,700
• Publication Number:
  US 20130114484A1
• Time in Patent Office: 959 Days
• Field of Search: 455/458, 455/437, 370/311, 370/329
• US Class Current: 370/329
• CPC Class Codes: H04W 16/32 Hierarchical cell structures
• CPC Class Codes: H04W 68/025 Indirect paging
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 76/28 Discontinuous transmission [DTX]; Discontinuous reception [DRX]
• CPC Class Codes: H04W 84/045 using private Base Stations, e.g. femto Base Stations, home Node B
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method for operating a UE in a wireless communications network is provided. The method comprises attempting, by a UE configured to operate in a DRX mode and with time domain measurement resource restrictions, to read a paging message in a paging occasion in a restricted subframe during DRX active time.

Claims

1. A method for operating a user equipment (UE) in a wireless communications network, the method comprising:

attempting, by a UE configured to operate in a discontinuous reception (DRX) mode and with time domain measurement resource restrictions, to read a paging message in a paging occasion in a restricted sub frame during DRX active time; and

receiving, by the UE, a configuration, wherein the configuration includes a DRX interval set to 5*2ⁿ frames and a DRX start offset that promotes the UE reading paging messages during the restricted sub frame within an on-duration and the UE not attempting to read paging messages in other sub frames and wherein n is a positive integer.

2. The method of claim 1, further comprising estimating, by the UE, available paging occasions based on paging control channel configurations, configured DRX parameters, and restricted sub frame patterns, wherein at least one of the paging control channel configurations, the configured DRX parameters, or the restricted sub frame patterns are configured such that the paging occasion coincides with a DRX on-duration period in which the UE monitors a physical downlink control channel (PDCCH).

3. The method of claim 1, further comprising:

estimating, by the UE, the probability of a target paging occasion being within the active time; and

determining, by the UE, which paging occasions to read based on the estimation in order to conserve battery power.

4. The method of claim 1, further comprising calculating, by the UE, the number of paging occasions to read by assuming that the probability of a target paging occasion being within the active time is proportional to current data activity.

5. The method of claim 1, wherein the wireless communications network is a heterogeneous network (HetNet) including a victim cell and an aggressor cell overlaying the victim cell, and wherein the restricted sub frame is scheduled to occur in the victim cell when an almost blank sub frame (ABS) is transmitted by an access node in the aggressor cell.

6. A user equipment (UE) comprising:

a memory device; and

a processor configured to execute computer readable instructions stored on the memory device such that when executed, the UE attempts to read a paging message in a paging occasion in a restricted sub frame during discontinuous reception (DRX) active time, wherein the UE is configured to operate in DRX mode and with time domain measurement resource restrictions,

the processor further configured such that the UE receives a configuration, wherein the configuration includes a DRX interval set to 5*2ⁿ sub frames and a DRX start offset that promotes the UE reading paging messages during the restricted sub frame within an on-duration and the UE not seeking to read paging messages in other sub frames, and wherein n is a positive integer.

7. The UE of claim 6, wherein the UE estimates available paging occasions based on paging control channel configurations, configured DRX parameters, and restricted sub frame patterns, and wherein at least one of the paging control channel configurations, the configured DRX parameters, or the restricted sub frame patterns are configured such that the paging occasion coincides with a DRX on-duration period in which the UE monitors a physical downlink control channel (PDCCH).

8. The UE of claim 6, wherein the UE estimates the probability of a target paging occasion being within the active time, and wherein the UE determines which paging occasions to read based on the estimation in order to conserve battery power.

9. The UE of claim 6, wherein the UE calculates the number of paging occasions to read by assuming that the probability of a target paging occasion being within the active time is proportional to current data activity.

10. A method for operating a network element in a wireless communications network, the method comprising:

configuring, by the network element, a discontinuous reception (DRX) cycle to 5*2ⁿ sub frames and a DRX start offset that aligns on-duration periods to paging occasions that are protected by restricted sub frames, wherein the network element is configured to utilize DRX and time domain measurement resource restrictions.

11. The method of claim 10, wherein the DRX start offset is set to 10*m+9 (m=0, 1, . . . floor((5*2n−

9)/10).

12. The method of claim 10, wherein the network element is a victim node in a heterogeneous network.

13. The method of claim 12, wherein the victim node is at least one of:

a pico cell;

a femto cell;

a relay;

or

a macro cell.

14. A network element in a wireless communications network, the network element comprising:

a memory device; and

a processor configured to execute computer readable instructions stored on the memory device such that when executed, the network element configures a discontinuous reception (DRX) cycle to 5*2ⁿ sub frames and a DRX start offset that aligns on-duration periods to paging occasions that are protected by restricted sub frames, wherein the network element is configured to utilize DRX and time domain measurement resource restrictions.

15. The network element of claim 14, wherein the DRX start offset is set to 10*m+9 (m=0, 1, . . . floor((5*2n−

9)/10).

16. The network element of claim 14, wherein the network element is a victim node in a heterogeneous network.

17. The network element of claim 16, wherein the victim node is at least one of:

a pico cell;

a femto cell;

a relay;

or

a macro cell.

18. A method for operating a user equipment (UE) in a wireless heterogeneous network, the method comprising:

attempting, by the UE, to read a paging message in selected sub frames;

monitoring, by the UE, a physical downlink control channel (PDCCH) to receive transmissions from at least one of an underlay cell or an overlay cell during an active time, wherein the sub frames are selected by the network to promote intercell interference coordination via a coordination method, the coordination method being an almost blank sub frame (ABS) technique in which the selected sub frames are scheduled to align in time with almost blank sub frames transmitted by the network; and

receiving, by the UE, a configuration, wherein the configuration includes a DRX interval set to 5*2ⁿ sub frames and a start offset that promotes the UE reading paging messages during the selected sub frames within an on-duration and the UE not seeking to read paging messages in other sub frames, and wherein n is a positive integer.

19. The method of claim 18, wherein the selected time interval duration is one of a value allocated to the UE by the network or a broadcast value.