# US 10,873,989 B1 · Method and apparatus for releasing sidelink radio bearer in a wireless communication system

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- Number: US 10,873,989 B1
- Document ID: US10873989B1
- Status: Granted
- Kind: B1
- Application number: 16/935,807
- Filed: 2020-07-22
- Granted: 2020-12-22
- Earliest claimed: 2019-08-02
- Assignees: ASUSTeK COMPUTER INC.
- Applicants: ASUSTek Computer Inc.
- Inventors: Li-Te Pan; Richard Lee-Chee Kuo
- Web page: https://patentgrep.com/patent/US10873989B1

## CPC

- H04W 76/14: Direct-mode setup
- H04W 76/30: Connection release
- H04W 4/40: for vehicles, e.g. vehicle-to-pedestrians [V2P]
- H04W 28/0268: {using specific QoS parameters for wireless networks, e.g. QoS class identifier [QCI] or guaranteed bit rate [GBR] (negotiating SLA or negotiating QoS H04W28/24)}
- H04W 28/10: Flow control {between communication endpoints}
- H04W 76/27: Transitions between radio resource control [RRC] states
- H04W 80/02: Data link layer protocols
- H04W 92/18: between terminal devices
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

A method and apparatus are disclosed from the perspective of a first UE (User Equipment) to indicate a network node for releasing SLRB (Sidelink Radio Bearer) or SL-DRB (Sidelink-Data Radio Bearer). In one embodiment, the method includes transmitting a first RRC (Radio Resource Control) message to a network node for requesting sidelink resource, wherein the first RRC message includes a PFI (PC5 QoS Flow Identifier) of a PC5 QoS (Quality of Service) flow in a first list of PC5 QoS flows. The method also includes receiving a second RRC message from the network node, wherein the second RRC message configures a SLRB and maps the PC5 QoS flow to the SLRB. The method further includes transmitting a third RRC message to the network node if the PC5 QoS flow is deactivated or released, wherein the PFI of the PC5 QoS flow is removed from a second list of PC5 QoS flows included in the third RRC message.

## Claims

### Claim 1

A method for a first UE (User Equipment) to indicate a network node for releasing SLRB (Sidelink Radio Bearer) or SL-DRB (Sidelink-Data Radio Bearer), comprising:
transmitting a first RRC (Radio Resource Control) message to a network node for requesting sidelink resource, wherein the first RRC message includes a PFI (PC5 QoS Flow Identifier) of a PC5 QoS (Quality of Service) flow in a first list of PC5 QoS flows;
receiving a second RRC message from the network node, wherein the second RRC message configures a SLRB and maps the PC5 QoS flow to the SLRB; and
transmitting a third RRC message to the network node if the PC5 QoS flow is deactivated or released, wherein the PFI of the PC5 QoS flow is removed from a second list of PC5 QoS flows included in the third RRC message.

### Claim 2 (depends on 1)

The method of claim 1, wherein the PC5 QoS flow is to be transmitted on a PC5 unicast link and the PC5 unicast link is established between the first UE and a second UE.

### Claim 3 (depends on 1)

The method of claim 1, further comprising:
receiving a fourth RRC message from the network node, wherein the fourth RRC message reconfigures the UE to release the SLRB.

### Claim 4 (depends on 3)

The method of claim 3, further comprising:
releasing the SLRB according to the fourth RRC message.

### Claim 5 (depends on 1)

The method of claim 1, wherein the PFI of the PC5 QoS flow is not included in the second list of PC5 QoS flows.

### Claim 6 (depends on 2)

The method of claim 2, wherein the first RRC message includes a destination Layer-2 ID associated with the PC5 unicast link.

### Claim 7 (depends on 6)

The method of claim 6, wherein the destination Layer-2 ID (Identity) is a Layer-2 ID of the second UE.

### Claim 8 (depends on 1)

The method of claim 1, wherein the first RRC message or the third RRC message is a SidelinkUEInformation.

### Claim 9 (depends on 3)

The method of claim 3, wherein the second RRC message or the fourth RRC message is a RRC reconfiguration message.

### Claim 10 (depends on 1)

The method of claim 1, wherein the network node is a base station.

### Claim 11

A first UE (User Equipment), comprising:
a control circuit;
a processor installed in the control circuit; and
a memory installed in the control circuit and operatively coupled to the processor;
wherein the processor is configured to execute a program code stored in the memory to:
transmit a first RRC (Radio Resource Control) message to a network node for requesting sidelink resource, wherein the first RRC message includes a PFI (PC5 QoS Flow Identifier) of a PC5 QoS (Quality of Service) flow in a first list of PC5 QoS flows;
receive a second RRC message from the network node, wherein the second RRC message configures a SLRB (Sidelink Radio Bearer) and map the PC5 QoS flow to the SLRB; and
transmit a third RRC message to the network node if the PC5 QoS flow is deactivated or released, wherein the PFI of the PC5 QoS flow is removed from a second list of PC5 QoS flows included in the third RRC message.

### Claim 12 (depends on 11)

The first UE of claim 11, wherein the PC5 QoS flow is to be transmitted on a PC5 unicast link and the PC5 unicast link is established between the first UE and a second UE.

### Claim 13 (depends on 11)

The first UE of claim 11, wherein the processor is further configured to execute a program code stored in the memory to:
receive a fourth RRC message from the network node, wherein the fourth RRC message reconfigures the UE to release the SLRB.

### Claim 14 (depends on 13)

The first UE of claim 13, wherein the processor is further configured to execute a program code stored in the memory to:
release the SLRB according to the fourth RRC message.

### Claim 15 (depends on 11)

The first UE of claim 11, wherein the PFI of the PC5 QoS flow is not included in the second list of PC5 QoS flows.

### Claim 16 (depends on 12)

The first UE of claim 12, wherein the first RRC message includes a destination Layer-2 ID associated with the PC5 unicast link.

### Claim 17 (depends on 16)

The first UE of claim 16, wherein the destination Layer-2 ID is a Layer-2 ID of the second UE.

### Claim 18 (depends on 11)

The first UE of claim 11, wherein the first RRC message or the third RRC message is a SidelinkUEInformation.

### Claim 19 (depends on 13)

The first UE of claim 13, wherein the second RRC message or the fourth RRC message is a RRC reconfiguration message.

### Claim 20 (depends on 11)

The first UE of claim 11, wherein the network node is a base station.