Apparatus and method for a connected mode with reduced signaling

• US 9,144,003 B2
• Filed: 03/12/2013
• Issued: 09/22/2015
• Est. Priority Date: 05/02/2012
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Radulescu, Andrei Dragos, Prakash, Rajat, Tinnakornsrisuphap, Peerapol, Singh, Damanjit, Patel, Chirag Sureshbhai
• Primary Examiner(s): Faroul, Farah
• Application Number:
  US13/797,991
• Publication Number:
  US 20130294405A1
• Time in Patent Office: 924 Days
• Field of Search: 370/311, 370/331, 370/332
• US Class Current: 1/1
• CPC Class Codes: H04W 16/32 Hierarchical cell structures
• CPC Class Codes: H04W 36/0033 with transfer of context information
• CPC Class Codes: H04W 36/0058 Transmission of hand-off measurement information, e.g. measurement reports
• CPC Class Codes: H04W 36/00695 using split of the control plane or user plane
• CPC Class Codes: H04W 36/0079 in case of hand-off failure or rejection
• CPC Class Codes: H04W 36/16 Performing reselection for specific purposes
• CPC Class Codes: H04W 36/165 for reducing network power consumption H04W36/18 - H04W36/22 take precedence
• CPC Class Codes: H04W 36/34 Reselection control

Abstract

A method, an apparatus, and a computer program product for wireless communication are provided. The apparatus preserves a state of a user equipment (UE) in an anchor evolved node B (eNB), wherein the anchor eNB is one of a set of connected cells, the UE being in a connected mode. Each cell of the connected set has a corresponding coverage area. The apparatus then maintains the state of the UE in the anchor eNB when the UE moves from a coverage area of the anchor eNB to a coverage area of another one of the cells from the set of connected cells.

Claims

1. A method of wireless communication for reducing hand over signaling at an evolved Node B (eNB), comprising:

forming a set of connected cells, each cell having a corresponding coverage area;

preserving a state of a user equipment (UE) in an anchor eNB, wherein the anchor eNB is one of the set of connected cells, wherein the UE is in a connected mode;

maintaining the state of the UE in the anchor eNB, when the UE moves from a coverage area of the anchor eNB to a coverage area of another one of the cells from the set of connected cells;

receiving a data packet at the anchor eNB; and

forwarding the data packet to each of the cells in the set of connected cells in order to transmit the data packet to the UE.

2. The method of claim 1, wherein the preserved state of the user equipment comprises one or both of a radio bearer (RAB) setting and a quality of service (QoS) setting for the UE.

3. The method of claim 1, further comprising:

transferring the state of the UE from the anchor eNB to a second cell in the set of connected cells when the UE contacts an Evolved UMTS Terrestrial Radio Access Network (E-UTRAN).

4. The method of claim 3, wherein the state of the UE is transferred from the anchor eNB to the second cell via one or both of X2 and S1.

5. The method of claim 3, further comprising:

receiving a communication from the UE at the E-UTRAN when the UE reselects to a cell that is not comprised in the set of connected cells.

6. The method of claim 3, further comprising:

receiving a communication from the UE at the E-UTRAN when the UE transmits uplink data.

7. The method of claim 3, further comprising:

prompting the UE to follow a legacy registration procedure when the state cannot be retrieved by the anchor eNB.

8. The method of claim 1, further comprising:

paging the UE at all of the cells in the set of connected cells in order to transmit downlink data to the UE.

9. The method of claim 1, further comprising:

using one or both of an idle paging procedure and a downlink data arriving procedure of the connected mode in order to communicate with the UE within the set of connected cells.

10. The method of claim 1, further comprising:

transmitting an identification of the set of connected cells to the UE, wherein the transmission comprises one or both of;

a broadcast transmission of an identifier for the set of connected cells, a list of neighboring cells comprised in the set of connected cells, a list of all cells in the set of connected cells, or a combination thereof; and

a unicast transmission of one or both of a list of neighbor cells comprised in the set of connected cells and an identifier for the set of connected cells.

11. The method of claim 10, wherein the transmission is sent via one or both of radio resource control signaling and non-access stratum signaling.

12. The method of claim 1, further comprising:

transmitting signaling to the UE to place the UE in a connected lite mode.

13. The method of claim 1, further comprising:

supplying a list of unused {NH, NCC} security pairs from the anchor eNB to a target eNB at a handover, wherein the target eNB is one of the set of connected cells, and wherein the handover comprises one of an X2 and an S1 type handover.

14. The method of claim 13, wherein the list of unused {NH, NCC} security pairs is supplied using one or both of a PATH SWITCH REQUEST ACKNOWLEDGE and an S1 HANDOVER REQUEST.

15. The method of claim 14, wherein, when the anchor eNB supplies an empty set of {NH, NCC} security pairs, the target eNB uses horizontally derived keys.

16. The method of claim 14, further comprising:

requesting a new set of {NH, NCC} security pairs from a mobility management entity, when there are no more unused {NH, NCC} security pairs.

17. The method of claim 16, wherein the request for additional {NH, NCC} security pairs is made in the form of a replicating handover from the anchor eNB to the target eNB, wherein after the replicating handover, the target eNB becomes the anchor eNB for the set of connected cells.

18. The method of claim 1, wherein when the UE exits coverage of the set of connected cells, the method further comprises:

transmitting a path switch request from the anchor eNB to a mobility management entity; and

transmitting an X2 message from the anchor eNB to a latest serving node.

19. The method of claim 1, further comprising:

receiving, at the anchor eNB, a request to retrieve the maintained state of the UE from a target cell outside of the set of connected cells, when the UE exits coverage of the set of connected cells.

20. The method of claim 1, wherein the anchor eNB acts as an S1 gateway between a mobility management entity (MME) and a latest serving node and between the MME and a potential target node, the latest serving node and the potential target node being in the set of connected cells.

21. The method of claim 20, the method further comprising:

routing an S1 message received from an MME to the latest serving node via the anchor eNB.

22. The method of claim 20, wherein the anchor eNB functions as an MME towards the latest serving node and a handover target node, both having a respective set of connected cells.

23. The method of claim 22, wherein the anchor eNB does not notify the MME of S1 signaling at handover, wherein a handover type between the serving and target eNBs comprises an S1-type or an X2-type.

24. The method of claim 1, further comprising:

routing, via the anchor eNB, an S1 message generated by a latest serving node in the set of connected cells.

25. The method of claim 24, wherein the S1 message comprises a path switch request.

26. A non-transitory computer readable medium storing computer executable code for reducing hand over signaling at an evolved Node B (eNB), comprising:

code for forming a set of connected cells, each cell having a corresponding coverage area;

code for preserving a state of a user equipment (UE) in an anchor eNB, wherein the anchor eNB is one of the set of connected cells, wherein the UE is in a connected mode;

code for maintaining the state of the UE in the anchor eNB, when the UE moves from a coverage area of the anchor eNB to a coverage area of another one of the cells from the set of connected cells;

code for receiving a data packet at the anchor eNB; and

code for forwarding the data packet to each of the cells in the set of connected cells in order to transmit the data packet to the UE.

27. The non-transitory computer readable medium of claim 26, wherein the preserved state of the user equipment comprises one or both of a radio bearer (RAB) setting and a quality of service (QoS) setting for the UE.

28. The non-transitory computer readable medium of claim 26, further comprising:

code for transferring the state of the UE from the anchor eNB to a second cell in the set of connected cells when the UE contacts an Evolved UMTS Terrestrial Radio Access Network (E-UTRAN).

29. An apparatus for wireless communication configured to reduce hand over signaling at an evolved Node B (eNB), comprising:

means for forming a set of connected cells, each cell having a corresponding coverage area;

means for preserving a state of a user equipment (UE) in an anchor eNB, wherein the anchor eNB is one of the set of connected cells, wherein the UE is in a connected mode and maintaining the state of the UE in the anchor eNB, when the UE moves from a coverage area of the anchor eNB to a coverage area of another one of the cells from the set of connected cells;

means for receiving a data packet at the anchor eNB; and

means for forwarding the data packet to each of the cells in the set of connected cells in order to transmit the data packet to the UE.

30. The apparatus of claim 29, wherein the preserved state of the user equipment comprises one or both of a radio bearer (RAB) setting and a quality of service (QoS) setting for the UE.

31. The apparatus of claim 29, further comprising:

means for communicating configured to transfer the state of the UE from the anchor eNB to a second cell in the set of connected cells when the UE contacts an Evolved UMTS Terrestrial Radio Access Network (E-UTRAN).

32. An apparatus for wireless communication configured to reduce hand over signaling at an evolved Node B (eNB), comprising:

a processing system including;

a connection module configured to form a set of connected cells, each cell having a corresponding coverage area;

a state preserving module configured to preserve a state of a user equipment (UE) in an anchor eNB, wherein the anchor eNB is one of the set of connected cells, wherein the UE is in a connected mode and to maintain the state of the UE in the anchor eNB, when the UE moves from a coverage area of the anchor eNB to a coverage area of another one of the cells from the set of connected cells; and

a communication module configured to receive a data packet at the anchor eNB and to forward the data packet to each of the cells in the set of connected cells in order to transmit the data packet to the UE.

33. The apparatus of claim 32, wherein the preserved state of the user equipment comprises one or both of a radio bearer (RAB) setting and a quality of service (QoS) setting for the UE.

34. The apparatus of claim 32, wherein the communication module is further configured to transfer the state of the UE from the anchor eNB to a second cell in the set of connected cells when the UE contacts an Evolved UMTS Terrestrial Radio Access Network (E-UTRAN).

35. The apparatus of claim 34, wherein the state of the UE is transferred from the anchor eNB to the second cell via one or both of an X2 and an S1.

36. The apparatus of claim 34, wherein the communication module is further configured to receive a communication from the UE at the E-UTRAN when the UE reselects to a cell that is not comprised in the set of connected cells.

37. The apparatus of claim 34, wherein the communication module is further configured to receive a communication from the UE at the E-UTRAN when the UE transmits uplink data.

38. The apparatus of claim 34, wherein the communication module is further configured to prompt the UE to follow a legacy registration procedure when the state cannot be retrieved by the anchor eNB.

39. The apparatus of claim 32, wherein the communication module is further configured to page the UE at all of the cells in the set of connected cells in order to transmit downlink data to the UE.

40. The apparatus of claim 32, wherein the communication module is further configured to use one or both of an idle paging procedure and a downlink data arriving procedure of the connected mode in order to communicate with the UE within the set of connected cells.

41. The apparatus of claim 32, wherein the communication module is further configured to transmit an identification of the set of connected cells to the UE, wherein the transmission comprises one or both of:

a broadcast transmission of an identifier for the set of connected cells, a list of neighboring cells comprised in the set of connected cells, a list of all cells in the set of connected cells, or a combination thereof; and

a unicast transmission of one or both of a list of neighbor cells comprised in the set of connected cells and an identifier for the set of connected cells.

42. The apparatus of claim 41, wherein the transmission is sent via one or both of radio resource control signaling and non-access stratum signaling.

43. The apparatus of claim 32, wherein the communication module is further configured to transmit signaling to the UE to place the UE in a connected lite mode.

44. The apparatus of claim 32, wherein the communication module is further configured to supply a list of unused {NH, NCC} security pairs from the anchor eNB to a target eNB at a handover, wherein the target eNB is one of the set of connected cells, and wherein the handover comprises one of an X2 and an S1 type handover.

45. The apparatus of claim 44, wherein the list of unused {NH, NCC} security pairs is supplied using one or both of a PATH SWITCH REQUEST ACKNOWLEDGE and a S1 HANDOVER REQUEST.

46. The apparatus of claim 45, wherein, when the anchor eNB is configured to supply an empty set of {NH, NCC} security pairs, the target eNB is configured to use horizontally derived keys.

47. The apparatus of claim 45, wherein the communication module is further configured to request a new set of {NH, NCC} security pairs from a mobility management entity, when there are no more unused {NH, NCC} security pairs.

48. The apparatus of claim 47, wherein the request for additional {NH, NCC} security pairs is made in the form of a replicating handover from the anchor eNB to the target eNB, wherein after the replicating handover, the target eNB is configured to become the anchor eNB for the set of connected cells.

49. The apparatus of claim 32, wherein when the UE is configured to exit coverage of the set of connected cells, the communication module is further configured to transmit a path switch request from the anchor eNB to a mobility management entity and to transmit an X2 message from the anchor eNB to a latest serving node.

50. The apparatus of claim 32, wherein the communication module is further configured to receive, at the anchor eNB, a request to retrieve the maintained state of the UE from a target cell outside of the set of connected cells, when the UE exits coverage of the set of connected cells.

51. The apparatus of claim 32, wherein the anchor eNB is configured to act as an S1 gateway between a mobility management entity (MME) and a latest serving node and between the MME and a potential target node, the latest serving node and the potential target node being in the set of connected cells.

52. The apparatus of claim 51, wherein the communication module is further configured to route an S1 message received from an MME to the latest serving node via the anchor eNB.

53. The apparatus of claim 51, wherein the anchor eNB is configured to function as an MME towards the latest serving node and a handover target node, both having a respective set of connected cells.

54. The apparatus of claim 53, wherein the anchor eNB is configured not to notify the MME of S1 signaling at handover, wherein a handover type between the serving and target eNBs comprises an S1-type or an X2-type.

55. The apparatus of claim 32, wherein the communication module is further configured to route, via the anchor eNB, an S1 message generated by a latest serving node in the set of connected cells.

56. The apparatus of claim 55, wherein the S1 message comprises a path switch request.

57. A method of wireless communication for reducing signaling at a user equipment (UE), comprising:

registering with an anchor eNB connected with a set of connected cells;

entering a connected lite mode upon an expiration of a timer related to discontinuous reception with the anchor eNB;

leaving a coverage area of the anchor eNB while in the connected lite mode; and

entering a coverage area of a second cell connected with the set of connected cells while in the connected lite mode, wherein a state of the UE is preserved at the anchor eNB.

58. The method of claim 57, wherein the UE leaves the coverage area of the anchor eNB and enters the coverage area of the second cell without registering with the second cell.

59. The method of claim 57, further comprising:

contacting an Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) in order to reselect to a cell that is not comprised in the set of connected cells.

60. The method of claim 57, further comprising:

contacting an Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) in order to transmit uplink data.

61. The method of claim 57, further comprising:

receiving a prompt to follow a legacy registration procedure when the state of the UE cannot be retrieved by the anchor eNB.

62. The method of claim 61, wherein the preserved state of the user equipment comprises one or both of a radio bearer (RAB) setting and a quality of service (QoS) setting for the UE.

63. The method of claim 57, further comprising:

receiving a page from the second cell, wherein the page is sent from all of the cells in the set of connected cells in order to transmit downlink data to the UE.

64. The method of claim 57, further comprising:

receiving communication from the second cell via an idle paging procedure, without performing a registration with the second cell.

65. The method of claim 57, further comprising:

receiving communication from the second cell via a downlink data arriving procedure of a connected mode without performing a registration with the second cell.

66. The method of claim 57, further comprising:

receiving an identification of the set of connected cells via one or both of a unicast and a broadcast.

67. The method of claim 66, wherein the identification is received as the broadcast of:

an identifier for the set of connected cells,

a list of neighboring cells comprised in the set of connected cells,

a list of all cells comprised in the set of connected cells, or

a combination thereof.

68. The method of claim 66, wherein the identification is received as the unicast of one or both of:

a list of neighbor cells comprised in the set of connected cells, and

an identifier for the set of connected cells.

69. The method of claim 66, wherein the identification is received via one or both of:

radio resource control signaling, and

non-access stratum signaling.

70. A non-transitory computer readable medium storing computer executable code for reducing signaling at a user equipment (UE), comprising:

code for registering with an anchor eNB connected with a set of connected cells; and

code for entering a connected lite mode upon an expiration of a timer related to discontinuous reception with the anchor eNB,

wherein when the UE leaves a coverage area of the anchor eNB while in the connected lite mode and enters a coverage area of a second cell connected with the set of connected cells while in the connected lite mode, a state of the UE is preserved at the anchor eNB.

71. The non-transitory computer readable medium of claim 70, wherein the UE leaves the coverage area of the anchor eNB and enters the coverage area of the second cell without registering with the second cell.

72. An apparatus for wireless communication configured to reduce signaling at a user equipment (UE), comprising:

means for registering with an anchor eNB connected with a set of connected cells; and

means for entering a connected lite mode upon an expiration of a timer related to discontinuous reception with the anchor eNB,

wherein when the apparatus is configured to leave a coverage area of the anchor eNB while in the connected lite mode and is configured to enter a coverage area of a second cell connected with the set of connected cells while in the connected lite mode, a state of the UE is preserved at the anchor eNB.

73. The apparatus of claim 72, wherein the apparatus is configured to leave the coverage area of the anchor eNB and is configured to enter the coverage area of the second cell without registering with the second cell.

74. An apparatus for wireless communication configured to reduce signaling at a user equipment (UE), comprising:

a processing system including;

a registration module configured to register with an anchor eNB connected with a set of connected cells; and

a connected lite module configured to enter a connected lite mode upon an expiration of a timer related to discontinuous reception with the anchor eNB,

wherein when the apparatus is configured to leave a coverage area of the anchor eNB while in the connected lite mode and is configured to enter a coverage area of a second cell connected with the set of connected cells while in the connected lite mode, a state of the UE is preserved at the anchor eNB.

75. The apparatus of claim 74, wherein the UE is configured to leave the coverage area of the anchor eNB and is configured to enter the coverage area of the second cell without registering with the second cell.

76. The apparatus of claim 74, further comprising:

a communication module configured to contact an Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) in order to reselect to a cell that is not comprised in the set of connected cells.

77. The apparatus of claim 74, further comprising:

a communication module configured to contact an Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) in order to transmit uplink data.

78. The apparatus of claim 74, further comprising:

a receiving module configured to receive a prompt to follow a legacy registration procedure when the state of the UE cannot be retrieved by the anchor eNB.

79. The apparatus of claim 78, wherein the preserved state of the user equipment comprises one or both of a radio bearer (RAB) setting and a quality of service (QoS) setting for the UE.

80. The apparatus of claim 74, further comprising:

a receiving module configured to receive a page from the second cell, wherein the page is sent from all of the cells in the set of connected cells in order to transmit downlink data to the UE.

81. The apparatus of claim 74, further comprising:

a receiving module configured to receive communication from the second cell via an idle paging procedure, without performing a registration with the second cell.

82. The apparatus of claim 74, further comprising:

a receiving module configured to receive communication from the second cell via a downlink data arriving procedure of a connected mode without performing a registration with the second cell.

83. The apparatus of claim 74, further comprising:

a receiving module configured to receive an identification of the set of connected cells via one or both of a unicast and a broadcast.

84. The apparatus of claim 83, wherein the receiving module is configured to receive the identification as the broadcast of:

an identifier for the set of connected cells,

a list of neighboring cells comprised in the set of connected cells,

a list of all cells comprised in the set of connected cells, or

a combination thereof.

85. The apparatus of claim 83, wherein the receiving module is configured to receive the identification as the unicast of one or both of:

a list of neighbor cells comprised in the set of connected cells, and

an identifier for the set of connected cells.

86. The apparatus of claim 85, wherein the receiving module is configured to receive the identification via one or both of:

radio resource control signaling, and

non-access stratum signaling.

87. A method of wireless communication for reducing signaling at a user equipment (UE), comprising:

registering with an anchor eNB connected with a set of connected cells;

receiving signaling instructing the UE to enter a connected lite mode;

entering the connected lite mode;

leaving a coverage area of the anchor eNB while in the connected lite mode; and

entering a coverage area of a second cell connected with the set of connected cells while in the connected lite mode, wherein a state of the UE is preserved at the anchor eNB.

88. The method of claim 87, wherein the UE leaves the coverage area of the anchor eNB and enters the coverage area of the second cell without registering with the second cell.

89. The method of claim 87, further comprising:

receiving a prompt to follow a legacy registration procedure when the state of the UE cannot be retrieved by the anchor eNB.

90. The method of claim 89, wherein the preserved state of the user equipment comprises one or both of a radio bearer (RAB) setting and a quality of service (QoS) setting for the UE.

91. An apparatus for wireless communication configured to reduce signaling at a user equipment (UE), comprising:

a transceiver;

at least one processor configured to;

register with an anchor eNB connected with a set of connected cells;

receive via the transceiver signaling instructing the UE to enter a connected lite mode; and

enter the connected lite mode,

wherein when the apparatus is configured to leave a coverage area of the anchor eNB while in the connected lite mode and is configured to enter a coverage area of a second cell connected with the set of connected cells while in the connected lite mode, a state of the UE is preserved at the anchor eNB; and

a memory coupled to the at least one processor.

92. The apparatus of claim 91, wherein the UE is configured to leave the coverage area of the anchor eNB and is configured to enter the coverage area of the second cell without registering with the second cell.

93. The apparatus of claim 91, wherein the at least one processor is further configured to receive a prompt to follow a legacy registration procedure when the state of the UE cannot be retrieved by the anchor eNB.

94. The apparatus of claim 93, wherein the preserved state of the user equipment comprises one or both of a radio bearer (RAB) setting and a quality of service (QoS) setting for the UE.

95. A non-transitory computer readable medium storing computer executable code for reducing signaling at a user equipment (UE), comprising:

code for registering with an anchor eNB connected with a set of connected cells;

code for receiving signaling instructing the UE to enter a connected lite mode; and

code for entering the connected lite mode,

wherein when the UE leaves a coverage area of the anchor eNB while in the connected lite mode and enters a coverage area of a second cell connected with the set of connected cells while in the connected lite mode, a state of the UE is preserved at the anchor eNB.

96. An apparatus for wireless communication configured to reduce signaling at a user equipment (UE), comprising:

means for registering with an anchor eNB connected with a set of connected cells;

means for receiving signaling instructing the UE to enter a connected lite mode; and

means for entering the connected lite mode,

wherein when the apparatus is configured to leave a coverage area of the anchor eNB while in the connected lite mode and is configured to enter a coverage area of a second cell connected with the set of connected cells while in the connected lite mode, a state of the UE is preserved at the anchor eNB.

97. An apparatus for wireless communication configured to reduce hand over signaling at an evolved Node B (eNB), comprising:

a transceiver;

at least one processor configured to;

form a set of connected cells, each cell having a corresponding coverage area;

preserve a state of a user equipment (UE) in an anchor eNB, wherein the anchor eNB is one of the set of connected cells, wherein the UE is in a connected mode;

maintain the state of the UE in the anchor eNB, when the UE moves from a coverage area of the anchor eNB to a coverage area of another one of the cells from the set of connected cells; and

receive a data packet at the anchor eNB and to forward the data packet to each of the cells in the set of connected cells in order to transmit the data packet to the UE; and

a memory coupled to the at least one processor.

98. An apparatus for wireless communication configured to reduce signaling at a user equipment (UE), comprising:

a transceiver;

at least one processor configured to;

register with an anchor eNB connected with a set of connected cells; and

enter a connected lite mode upon an expiration of a timer related to discontinuous reception with the anchor eNB,

wherein when the apparatus is configured to leave a coverage area of the anchor eNB while in the connected lite mode and is configured to enter a coverage area of a second cell connected with the set of connected cells while in the connected lite mode, a state of the UE is preserved at the anchor eNB; and

a memory coupled to the at least one processor.