Mobility Robustness in a Cellular Network

Patent metadata

Field	Value
Publication number	US-2016285679-A1
Application number	US-201514414512-A
Country	US
Kind code	A1
Filing date	Jan 8, 2015
Priority date	Mar 21, 2014
Publication date	Sep 29, 2016
Grant date	—

Abstract

The present invention relates to a method in a node of a cellular network for supporting mobility, to a method in a user equipment for supporting mobility to in the cellular network, and to corresponding devices. According to one aspect, a method for supporting mobility in a cellular network is provided. The method runs in a node for the cellular network. According to the method, the node receives from a user equipment, an information of a radio link failure of a radio link between the user equipment and the cellular network and the node receives information related to a mobility of the user equipment. Based on the received information, the node adjusts at least one mobility parameter to increase robustness of mobility. The present invention improves robustness of mobility functions in a cellular network.

First claim

1 - 32 . (canceled)

33 . A method, in a node for a cellular network, for supporting mobility in the cellular network, the method comprising:
the node receiving, from a user equipment, information of a radio link failure of a radio link between the user equipment and the cellular network; the node receiving information related to a mobility of the user equipment; the node adjusting, based on the received information, at least one mobility parameter to increase robustness of mobility.

34 . The method of claim 33 , wherein the information related to a mobility of the user equipment comprises information on an expiry of a handover timer.

35 . The method of claim 34 , wherein the handover timer is a T312 timer.

36 . The method of claim 33 , further comprising the node sending the adjusted mobility parameter to a user equipment.

37 . The method of claim 33 , wherein the information related to the mobility of the user equipment comprises information of at least one of:
a handover configuration; a handover timer; a radio link failure timer; whether the user equipment has sent a measurement report; whether the network has received a measurement report from the user equipment; a failure cause; expiry of a handover timer; expiry of a radio link failure timer; whether a handover timer has expired; a list of cells fulfilling measurement report triggering conditions; a measurement event; a time period since a handover timer is triggered; a time period between sending a measurement report and occurrence of a radio link failure; a time period since a handover timer is running; a time period since a radio link failure timer is running.

38 . The method of claim 33 , further comprising:
the node determining, from the information related to the mobility, whether a measurement report has been sent by the user equipment; the node adjusting the at least one mobility parameter to increase robustness of mobility also based on the determination whether a measurement report has been sent.

39 . The method of claim 33 , further comprising the node receiving information on a radio link monitoring (RLM) configuration.

40 . The method of claim 39 , wherein the RLM configuration comprises information on at least one of a radio link failure timer and a handover timer.

41 . The method of claim 33 , further comprising the node adjusting at least one mobility parameter to increase robustness of mobility also based on a context of the user equipment.

42 . The method of claim 33 , further comprising the node adjusting at least one mobility parameter to increase robustness of mobility also based on a mobility state estimate of the user equipment.

43 . The method of claim 33 , wherein the adjustment is made on a per cell level.

44 . The method of claim 33 , further comprising the node receiving, from the user equipment, a report comprising some or all of the received information.

45 . The method of claim 33 , wherein the received information is received in a radio link failure (RLF) report.

46 . The method of claim 33 , wherein the at least one mobility parameter is at least one of:
a cell individual offset (CIO); a handover threshold; a parameter indicative of a threshold signal strength of a target cell required for triggering a mobility event; a parameter indicative of a threshold signal strength of a serving cell required for triggering a mobility event; a coefficient to be applied to a measurement utilized to trigger a mobility event a parameter indicative of a time period during which a trigger condition is to be met for actually triggering a mobility event; a handover timer; a radio link failure timer; a handover event offset; a Time To Trigger (TTT); a handover event configuration; an indication to remove a cell from a carrier frequency; a time period between receiving a measurement report and transmitting a handover request.

47 . A method, in a user equipment, for supporting mobility in a cellular network, the method comprising:
the user equipment detecting a failure of a radio link between the user equipment and the cellular network; the user equipment sending, to a node of the cellular network, an information of the radio link failure of a radio link between the user equipment and the cellular network; the user equipment sending information related to a mobility of the user equipment to the node.

48 . The method of claim 47 , wherein the information related to a mobility of the user equipment comprises information on an expiry of a handover timer.

49 . The method of claim 48 , wherein the handover timer is a T312 timer.

50 . The method of claim 47 , further method comprising the user equipment receiving at least one adjusted mobility parameter from the node.

51 . The method of claim 50 , wherein the at least one adjusted mobility parameter is at least one of:
a cell individual offset (CIO); a handover threshold; a parameter indicative of a threshold signal strength of a target cell required for triggering a mobility event; a parameter indicative of a threshold signal strength of a serving cell required for triggering a mobility event; a coefficient to be applied to a measurement utilized to trigger a mobility event; a parameter indicative of a time period during which a trigger condition is to be met for actually triggering a mobility event; a handover timer; a radio link failure timer; a handover event offset; a Time To Trigger (TTT); a handover event configuration; an indication to remove a cell from a carrier frequency; a time period between receiving a measurement report and transmitting a handover request.

52 . The method of claim 47 , wherein the information related to the mobility of the user equipment comprises information of at least one of:
a handover configuration; a handover timer; a radio link failure timer; whether the user equipment has send a measurement report; whether the network has received a measurement report from the user equipment; a failure cause; expiry of a handover timer; expiry of a radio link failure timer; whether a handover timer has expired; a list of cells fulfilling measurement report triggering conditions; a measurement event; a time period since a handover timer is triggered; a time period between sending a measurement report and occurrence of a radio link failure; a time period since a handover timer is running; a time period since a radio link failure timer is running.

53 . The method of claim 47 , further comprising the user equipment sending information on a radio link monitoring (RLM) configuration.

54 . The method of claim 53 , wherein the RLM configuration comprises information on at least one of a radio link failure timer and a handover timer.

55 . The method of claim 47 , further comprising the user equipment sending a report comprising some or all of the sent information.

56 . The method of claim 47 , wherein the sent information is sent in a radio link failure (RLF) report.

57 . A node for a cellular network and for supporting mobility in the cellular network, the node comprising:
at least one interface; at least one processing circuit configured to:
receive, from a user equipment and via the at least one interface, information of a radio link failure of a radio link between the user equipment and the cellular network;
receive info

Assignees

• ERICSSON TELEFON AB L M (publ)

Inventors

• Dudda Torsten
• Centonza Angelo
• Folke Mats
• Wager Stefan
• Yavuz Emre

Classifications

• H04W40/36

  due to handover · CPC title

• H04W40/12

  based on transmission quality or channel quality · CPC title

• H04L43/0817

  by checking functioning · CPC title

• H04W24/02 Primary

  Arrangements for optimising operational condition · CPC title

• H04W76/19

  Connection re-establishment · CPC title