# US 11,452,161 B2 · Packet data network connection re-establishment

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- Number: US 11,452,161 B2
- Document ID: US11452161B2
- Status: Granted
- Kind: B2
- Application number: 16/889,968
- Filed: 2020-06-02
- Published: 2020-12-03
- Granted: 2022-09-20
- Earliest claimed: 2019-06-03
- Assignees: Apple Inc.
- Applicants: Apple Inc.
- Inventors: Vijay Venkataraman; Rohit Matolia; Alosious Pradeep Prabhakar
- Web page: https://patentgrep.com/patent/US11452161B2

## CPC

- H04W 76/19: Connection re-establishment
- H04W 8/20: Transfer of user or subscriber data
- H04W 76/25: Maintenance of established connections
- H04W 76/27: Transitions between radio resource control [RRC] states
- H04W 76/30: Connection release
- H04W 8/183: {Processing at user equipment or user record carrier}
- H04W 76/34: Selective release of ongoing connections
- H04W 88/06: adapted for operation in multiple networks {or having at least two operational modes}, e.g. multi-mode terminals
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

This disclosure relates to techniques for a wireless device to re-establish a packet data network connection. The wireless device may establish a packet data network connection via a cellular link with a cellular base station. Information identifying a bearer associated with the packet data network connection may be stored by the wireless device. The wireless device may determine whether the bearer associated with the packet data network connection is active. The packet data network connection may be released by the wireless device and the wireless device may attempt to re-establish the packet data network connection if the bearer associated with the packet data network connection is determined to not be active.

## Claims

### Claim 1

An apparatus, comprising:
at least one processor configured to cause a dual subscriber identity module (SIM) dual standby (DSDS) wireless device to:
establish a cellular link with a cellular base station using a first SIM;
establish a packet data network (PDN) connection using the first SIM;
store information identifying a bearer associated with the PDN connection;
interrupt using receiver circuitry of the wireless device for the first SIM to communicate using a second SIM, wherein the wireless device does not monitor the cellular link with the cellular base station while the receiver circuitry of the wireless device is used to communicate using the second SIM;
resume using receiver circuitry of the wireless device for the first SIM;
determine whether the bearer associated with the PDN connection is active after resuming using receiver circuitry of the wireless device for the first SIM based at least in part on the interruption to using receiver circuitry of the wireless device for the first SIM, wherein said determining whether the bearer associated with the PDN is active comprises:
receiving radio resource control (RRC) reconfiguration information indicating bearer identification information for all active bearers for the wireless device; and
determining whether the RRC reconfiguration information indicates bearer identification information for the bearer associated with the PDN connection, wherein it is determined that the bearer associated with the PDN connection is active if the RRC reconfiguration information indicates bearer identification information for the bearer associated with the PDN connection, wherein it is determined that the bearer associated with the PDN connection is not active if the RRC reconfiguration information does not indicate bearer identification information for the bearer associated with the PDN connection; and
release the PDN connection if it is determined that the bearer associated with the PDN connection is not active.

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein to determine whether the bearer associated with the PDN connection is active, the at least one processor is further configured to cause the wireless device to:
send dummy data via the bearer associated with the PDN connection; and
determine whether acknowledgement of the dummy data sent via the bearer associated with the PDN connection is received,
wherein it is determined that the bearer associated with the PDN connection is active if acknowledgement of the dummy data sent via the bearer associated with the PDN connection is received, wherein it is determined that the bearer associated with the PDN connection is not active if acknowledgement of the dummy data sent via the bearer associated with the PDN connection is not received.

### Claim 3 (depends on 1)

The apparatus of claim 1,
wherein the PDN connection is associated with a service type,
wherein determining whether the bearer associated with the PDN connection is active after resuming using receiver circuitry of the wireless device for the first SIM is further based at least in part on one or more conditions associated with the service type being met,
wherein the at least one processor is further configured to cause the wireless device to attempt to re-establish the PDN connection based at least in part on the one or more conditions associated with the service type being met.

### Claim 4 (depends on 3)

The apparatus of claim 3,
wherein the one or more conditions associated with the service type comprise the service type being in active use at the wireless device.

### Claim 5 (depends on 3)

The apparatus of claim 3,
wherein the one or more conditions associated with the service type comprise a timer associated with possible data activity according to the service type being unexpired.

### Claim 6 (depends on 1)

The apparatus of claim 1,
wherein the cellular link includes an LTE link,
wherein the bearer associated with the PDN connection includes an evolved packet service (EPS) bearer.

### Claim 7

A wireless device, comprising:
an antenna;
a radio operably coupled to the antenna; and
at least one processor operably coupled to the radio;
wherein the wireless device is configured to:
establish a packet data network (PDN) connection via a cellular link with a cellular base station, wherein the PDN connection is established by a non-access stratum (NAS) layer of the wireless device;
store information identifying a bearer associated with the PDN connection at a radio resource control (RRC) layer of the wireless device;
determine, at the RRC layer, that the bearer associated with the PDN connection is not active, wherein determining that the bearer associated with the PDN connection is not active is performed based at least in part on operating in RRC idle mode for at least a threshold amount of time after the PDN connection is established;
provide an indication from the RRC layer to the NAS layer that the bearer associated with the PDN connection is not active; and
release the PDN connection at the NAS layer based at least in part on the indication that the bearer associated with the PDN connection is not active.

### Claim 8 (depends on 7)

The wireless device of claim 7, wherein to determine that the bearer associated with the PDN connection is not active, the wireless device is further configured to:
receive radio resource control (RRC) reconfiguration information indicating bearer identification information for all active bearers for the wireless device; and
determine that the RRC reconfiguration information does not indicate bearer identification information for the bearer associated with the PDN connection.

### Claim 9 (depends on 7)

The wireless device of claim 7, wherein to determine whether the bearer associated with the PDN connection is active, the wireless device is further configured to:
send dummy data via the bearer associated with the PDN connection; and
determine that no acknowledgement of the dummy data sent via the bearer associated with the PDN connection is received.

### Claim 10 (depends on 7)

The wireless device of claim 7, wherein the wireless device is further configured to:
determine whether one or more conditions for keeping the PDN connection active are met; and
attempt to re-establish the PDN connection at the NAS layer if one or more conditions for keeping the PDN connection active are met.

### Claim 11 (depends on 10)

The wireless device of claim 10, wherein the one or more conditions for keeping the PDN connection active comprise one or more of:
one or more application types or service types associated with the PDN connection being active at the wireless device; or
a timer associated with keeping the PDN connection active being unexpired.

### Claim 12 (depends on 7)

The wireless device of claim 7,
wherein the wireless device comprises a dual subscriber identity module (SIM) dual standby (DSDS) wireless device,
wherein determining that the bearer associated with the PDN connection is not active is performed based at least in part on an interruption to using a first SIM of the DSDS wireless device caused by use of a second SIM of the DSDS wireless device.

### Claim 13

A method, comprising:
by a wireless device:
establishing a radio resource control (RRC) connection with a cellular base station;
establishing a packet data network (PDN) connection via the RRC connection, wherein the PDN connection is established based at least in part on an application type associated with the PDN connection being active at the wireless device;
storing information identifying a bearer associated with the PDN connection;
releasing the RRC connection, wherein the wireless device operates in RRC idle mode after the RRC connection is released;
re-establishing a RRC connection with a cellular base station;
determining whether an application type associated with the PDN connection is active at the wireless device after re-establishing the RRC connection with a cellular base station;
determining whether the bearer associated with the PDN connection is active after re-establishing the RRC connection with a cellular base station;
releasing the PDN connection if the bearer associated with the PDN connection is not active; and
attempting to re-establish the PDN connection based at least in part on releasing the PDN connection, wherein determining whether the bearer associated with the PDN connection is active after re-establishing the RRC connection, releasing the PDN connection if the bearer associated with the PDN connection is not active, and attempting to re-establish the PDN connection are performed based at least in part on determining that an application type associated with the PDN connection is active at the wireless device after re-establishing the RRC connection.

### Claim 14 (depends on 13)

The method of claim 13, wherein determining whether the bearer associated with the PDN connection is active after re-establishing the RRC connection further comprises:
receiving RRC reconfiguration information indicating bearer identification information for all active bearers for the wireless device; and
determining whether the RRC reconfiguration information indicates bearer identification information for the bearer associated with the PDN connection.

### Claim 15 (depends on 13)

The method of claim 13, wherein determining whether the bearer associated with the PDN connection is active further comprises:
sending data via the bearer associated with the PDN connection; and
determining whether acknowledgement of the data sent via the bearer associated with the PDN connection is received.

### Claim 16 (depends on 13)

The method of claim 13,
wherein the application type associated with the PDN connection comprises one or more of:
a gaming application;
an augmented reality (AR) application; or
an internet protocol (IP) multimedia subsystem (IMS) application.

### Claim 17 (depends on 13)

The method of claim 13, wherein the method further comprises:
determining whether a timer associated with the PDN connection is expired after re-establishing the RRC connection with a cellular base station,
wherein determining whether the bearer associated with the PDN connection is active after re-establishing the RRC connection, releasing the PDN connection if the bearer associated with the PDN connection is not active, and attempting to re-establish the PDN connection are performed based at least in part on determining that the timer associated with the PDN connection is not expired after re-establishing the RRC connection.

### Claim 18 (depends on 13)

The method of claim 13, wherein said attempting to re-establish the PDN connection is further based on a timer associated with possible data associated with the application type being unexpired.

### Claim 19 (depends on 13)

The method of claim 13, wherein determining whether the bearer associated with the PDN connection is active is performed based at least in part on operating in RRC idle mode for at least a threshold amount of time after the PDN connection is established.

### Claim 20 (depends on 13)

The method of claim 13, wherein the wireless device comprises a dual subscriber identity module (SIM) dual standby (DSDS) wireless device, wherein determining whether the bearer associated with the PDN connection is active is performed based at least in part on an interruption to using a first SIM of the DSDS wireless device caused by use of a second SIM of the DSDS wireless device.