Radio link failure handling for dual connectivity

Patent metadata

Field	Value
Publication number	US-10015807-B2
Application number	US-201715614208-A
Country	US
Kind code	B2
Filing date	Jun 5, 2017
Priority date	Oct 31, 2013
Publication date	Jul 3, 2018
Grant date	Jul 3, 2018

Abstract

Embodiments of an evolved Node B (eNB) and methods for radio link failure handling for dual connectivity are generally described herein. A method performed by circuitry of a User Equipment (UE) may include connecting, at a UE, to a Master eNB (MeNB) and connecting to a Secondary eNB (SeNB). The method may include determining, at the UE, that one of the connections has a Radio Link Failure and determining at the UE, that the other of the connections remains connected to the UE. The method may include refraining from initiating a Radio Resource Control (RRC) re-establishment procedure while at least one of the connections does not have a radio link failure.

First claim

What is claimed is:

1. An apparatus of a user equipment (UE), the apparatus comprising:
a transceiver configured to transmit and receive communications with a Master evolved Node-B (MeNB) and a Secondary evolved Node-B (SeNB) when the UE is configured with dual connectivity (DC); and
processing circuitry coupled to the transceiver, the processing circuitry configured to detect a radio link failure (RLF) for the SeNB, and upon detecting the RLF:
encode for transmission to the MeNB, a radio resource control (RRC) indication that the connection with the SeNB has experienced RLF;
suspend radio bearers for the SeNB based on the detected RLF for the SeNB;
reset a media access control (MAC) layer associated with communications with the SeNB;
release a serving cell configuration of the SeNB in response to a request from the MeNB, upon determining the connection with the SeNB has experienced the RLF, and
maintain connection with radio bearers for the MeNB in a non-DC configuration.

2. The apparatus of claim 1 , wherein the radio bearers for the SeNB include a data radio bearer (DRB).

3. The apparatus of claim 1 , wherein the radio bearers for the SeNB include a split DRB.

4. The apparatus of claim 1 , wherein the processing circuitry is configured to:
determine the connection with the SeNB has the RLF based on an expiration of an out-of-sync timer indicating lack of synchronization with the SeNB.

5. The apparatus of claim 1 , wherein the processing circuitry is configured to:
determine the connection with the SeNB has the RLF based on a random access problem indication received from a media access control (MAC) layer.

6. The apparatus of claim 1 , wherein the processing circuitry is configured to:
decode an indication from a radio link control (RLC) layer of the SeNB that a maximum number of retransmissions has been reached for a secondary cell group (SCG) of the SeNB; and
determine a connection with the SeNB has the RLF based on the decoded indication.

7. The apparatus of claim 1 , wherein the processing circuitry is configured to:
refrain from initiating a radio resource control (RRC) re-establishment procedure between the UE and the SeNB while a connection between the UE and the MeNB does not have a RLF.

8. The apparatus of claim 1 , wherein the processing circuitry is configured to:
upon detecting the RLF with the SeNB, apply one of a default physical channel configuration or a default semi-persistent scheduling configuration to maintain a connection with the MeNB.

9. The apparatus of claim 1 , wherein the processing circuitry is configured to:
reconfigure at least one radio bearer served by the SeNB in response to the request from the MeNB.

10. An apparatus of a user equipment (LT the apparatus comprising:
processing circuitry, the processing circuitry configured to:
detect a radio link failure (RIF) for a Secondary evolved Node-B (SeNB), while the UE is in a dual connectivity (DC) state with the SeNB and a Master evolved Node-B (MeNB), wherein the MeNB is associated with a Primary Cell (PCell) and the SeNB is associated with a Secondary Cell (SCell); and
upon detecting the RLF:
encode for transmission to the MeNB, a radio resource control (RRC) indication that the connection with the SeNB has experienced RLF;
suspend radio bearers for the SeNB, wherein the radio bearers for the SeNB include a data radio bearer (DRB) or a split DRB;
reset a media access control (MAC) layer associated with communications with the SeNB;
decode a Radio Resource Control reconfiguration message from the MeNB to remove the SCell from a set of cells serving the UE; and
maintain connection with radio bearers for the MeNB in a non-DC configuration.

11. The apparatus of claim 10 , wherein the processing circuitry is configured to:
determine the connection with the SeNB has the RLF based on an expiration of an out-of-sync timer indicating lack of synchronization with the SeNB.

12. The apparatus of claim 10 , wherein the processing circuitry is configured to:
determine the connection with the SeNB has the RLF based on a random access problem indication received from the MAC layer associated with communications to the SeNB.

13. The apparatus of claim 10 , wherein the processing circuitry is configured to:
decode an indication from a radio link control (RLC) layer of the SeNB that a maximum number of retransmissions has been reached for SCell of the SeNB; and
determine a connection with the SeNB has the RLF based on the decoded indication.

14. A non-transitory computer readable storage device including instructions stored thereon, which when executed by one or more processors of a User Equipment (UE), cause the UE to perform operations to:
detect a radio link failure (RLF) for a Secondary evolved Node-B (SeNB), while the UE is in a dual connectivity (DC) state with a secondary cell (SCell) of the SeNB and a primary cell (Pcell) of a Master evolved Node-B (MeNB);
encode for transmission to the MeNB, a radio resource control (RRC) indication that the connection with the SeNB has experienced RLF;
suspend radio bearers for the SeNB, wherein the radio bearers for the SeNB include a data radio bearer (DRB) or a split DRB;
reset a media access control (MAC) layer associated with communications to the SeNB;
decode a Radio Resource Control reconfiguration message from the MeNB to remove the SCell from a set of cells serving the UE, and
maintain connection with radio bearers for the MeNB in a non-DC configuration.

15. The non-transitory computer readable storage device of claim 14 , wherein the instructions further cause the UE to perform operations to:
determine the connection with the SeNB has the RLF based on an expiration of an out-of-sync timer indicating lack of synchronization with the SeNB.

Assignees

• Intel Ip Corp

Inventors

• Heo Youn Hyoung
• Zhang Yujian

Classifications

• H04W72/52

  based on load · CPC title

• H04W72/51

  based on terminal or device properties · CPC title

• H04W72/542

  using measured or perceived quality · CPC title

• H04W72/56 Primary

  based on priority criteria · CPC title

• H04W36/305

  Handover due to radio link failure (control signalling for hand-off failure H04W36/0079) · CPC title