# US 12,225,632 B2 · Method and user equipment for handling user plane in dual connectivity in wireless communication system

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- Number: US 12,225,632 B2
- Document ID: US12225632B2
- Status: Granted
- Kind: B2
- Application number: 18/346,040
- Filed: 2023-06-30
- Published: 2023-10-26
- Granted: 2025-02-11
- Earliest claimed: 2017-09-29
- Assignees: Samsung Electronics Co., Ltd.
- Applicants: Samsung Electronics Co., Ltd.
- Inventors: Neha Sharma; Mangesh Abhimanyu Ingale
- Web page: https://patentgrep.com/patent/US12225632B2

## CPC

- H04W 80/02: Data link layer protocols
- H04W 12/033: of the user plane, e.g. user's traffic
- H04W 12/04: Key management, e.g. using generic bootstrapping architecture [GBA]
- H04W 76/15: Setup of multiple wireless link connections
- H04W 76/27: Transitions between radio resource control [RRC] states
- H04W 76/19: Connection re-establishment
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

Embodiments herein provide a method for handling a user plane by a UE configured for dual connectivity operation. The method includes receiving a RRC reconfiguration message including one or more Layer 2 indications and a Layer 2 configuration corresponding to one or more radio bearers from one of a MN and a SN involved in a dual connectivity operation of the UE. Further, the method includes performing, by the UE, one of: reestablishing of a RLC entity and a data recovery procedure for a PDCP entity corresponding to the radio bearer based on the one or more Layer 2 indications and the Layer 2 configuration received in the RRC reconfiguration message, and reestablishing of a RLC entity and reestablishing of a PDCP entity corresponding to the radio bearer based on the one or more Layer 2 indications and the Layer 2 configuration received in the RRC reconfiguration message.

## Claims

### Claim 1

A method by a user equipment (UE) performing communication with a master node (MN) and a secondary node (SN) in a wireless communication network, the method comprising:
establishing connections between the MN, the SN and the UE, the UE configured with an evolved-UMTS terrestrial radio access (E-UTRAN) and new radio access network (NR) dual connectivity (EN-DC), wherein the UE comprises radio link control (RLC) entities including an E-UTRA RLC entity and a NR RLC entity, and wherein a master cell group (MCG) bearer, a secondary cell group (SCG) bearer, or a split bearer is configured for a RLC entity;
identifying information indicating bearer type change;
in response to identifying the information indicating the bearer type change of re-establishment of a RLC entity for a radio bearer (RB), performing re-establishment of the RLC entity for the RB; and
in response to identifying the information indicating the bearer type change of release of a RLC entity, performing the release of the RLC entity for the RB.

### Claim 2 (depends on 1)

The method of claim 1, wherein the information is received through a Radio Resource Control (RRC) reconfiguration message including one or more Layer 2 (L2) information, and
wherein the method further comprises identifying at least one RB corresponding to a current configuration of the UE, from the one or more L2 information.

### Claim 3 (depends on 2)

The method of claim 2, further comprising: in response to data radio bearer (DRB) identity included in the one or more L2 information being not a part of the current configuration of the UE,
obtaining key information for the DRB identity based on the one or more L2 information; and
applying a key, based on the key information, to a packet data convergence protocol (PDCP) entity.

### Claim 4 (depends on 2)

The method of claim 2, further comprising:
obtaining information indicating recovery of a PDCP entity based on the one or more L2 information; and
performing retransmission of PDCP data protocol data units (PDUs) of a released RLC entity upon reception of a PDCP recovery information.

### Claim 5 (depends on 4)

The method of claim 4, wherein performing retransmission comprises retransmitting the PDCP data PDUs previously submitted to re-established or released acknowledged mode RLC (AM RLC) entity in ascending order of associated count values from a first PDCP Data PDU for which successful delivery has not been confirmed by lower sub-layers.

### Claim 6 (depends on 1)

The method of claim 1, further comprising:
when identifying the information indicating the bearer type change of the release of the RLC entity for a RB,
performing a discard of RLC service data units (SDUs) and RLC PDUs and the release of the RLC entity.

### Claim 7 (depends on 1)

The method of claim 1, wherein in response to a medium access control (MAC) entity receiving a MAC PDU for the MAC entity cell-radio network temporary identifier (C-RNTI) or Semi-Persistent Scheduling C-RNTI, discarding a sub-PDU in the received MAC PDU.

### Claim 8 (depends on 1)

The method of claim 1, wherein in response to a MAC entity receiving a MAC PDU containing reserved or invalid values, via a configured downlink assignment, discarding a sub-PDU in the received MAC PDU.

### Claim 9

A user equipment (UE) for performing communication with a master node (MN) and a secondary node (SN) in a wireless communication network, the UE comprising:
a transceiver to transmit or receive radio signals from the MN and the SN; and
a processor configured to:
establish connections between the MN, the SN and the UE, the UE configured with an evolved-UMTS terrestrial radio access (E-UTRAN) and new radio access network (NR) dual connectivity (EN-DC), wherein the UE comprises radio link control (RLC) entities including an E-UTRA RLC entity and a NR RLC entity, and wherein a master cell group (MCG) bearer, a secondary cell group (SCG) bearer, or a split bearer is configured for a RLC entity;
identify information indicating bearer type change;
in response to identifying the information indicating the bearer type change of re-establishment of a RLC entity for a radio bearer (RB), perform the re-establishment of the RLC entity for the RB; and
in response to identifying the information indicating the bearer type change of release of a RLC entity, perform the release of the RLC entity for the RB.

### Claim 10 (depends on 9)

The UE of claim 9, wherein the one or more information is received through a Radio Resource Control (RRC) reconfiguration message including one or more Layer 2 (L2) information, and
the processor is further configured to identify at least one RB corresponding to a current configuration of the UE, from the information.

### Claim 11 (depends on 10)

The UE of claim 10, the processor is further configured to, in response to identifying a data radio bearer (DRB) identity included in the one or more L2 information being not a part of the current configuration of the UE,
obtain key information for the identified DRB identity based on the one or more L2 information; and
apply a key, based on the key information, to a packet data convergence protocol (PDCP) entity.

### Claim 12 (depends on 10)

The UE of claim 10, wherein the processor is further configured to:
obtain information indicating recovery of a PDCP entity based on the one or more L2 information; and
perform retransmission of PDCP data protocol data units (PDUs) of a released RLC entity upon reception of a PDCP recovery information.

### Claim 13 (depends on 12)

The UE of claim 12, wherein the processor is further configured to:
control the transceiver to retransmit the PDCP data PDUs previously submitted to re-established or released acknowledged mode RLC (AM RLC) entity in ascending order of associated count values from a first PDCP Data PDU for which successful delivery has not been confirmed by lower sub-layers.

### Claim 14 (depends on 9)

The UE of claim 9, wherein the processor is further configured to:
when identifying the information indicating the bearer type change of the release of the RLC entity for a RB,
perform a discard of RLC service data units (SDUs) and RLC PDUs and the release of the RLC entity.

### Claim 15 (depends on 9)

The UE of claim 9, wherein the processor is further configured to:
in response to a medium access control (MAC) entity receiving a MAC PDU for the MAC entity cell-radio network temporary identifier (C-RNTI) or Semi-Persistent Scheduling C-RNTI, discard a sub-PDU in the received MAC PDU.

### Claim 16 (depends on 9)

The UE of claim 9, wherein the processor is further configured to:
in response to a MAC entity receiving a MAC PDU containing reserved or invalid values, via a configured downlink assignment, discard a sub-PDU in the received MAC PDU.