# US 11,122,422 B2 · Gateway device, mobility management device, base station, communication method, control method, paging method, and computer-readable medium

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- Number: US 11,122,422 B2
- Document ID: US11122422B2
- Status: Granted
- Kind: B2
- Application number: 16/346,796
- Filed: 2017-11-02
- Published: 2019-08-29
- Granted: 2021-09-14
- Earliest claimed: 2016-11-02
- Assignees: NEC Corporation
- Applicants: NEC Corporation
- Inventors: Toshiyuki Tamura; Kouji Shimizu
- Web page: https://patentgrep.com/patent/US11122422B2

## CPC

- H04W 8/30: Network data restoration; {Network data reliability; Network data fault tolerance}
- H04W 8/26: Network addressing or numbering for mobility support
- H04W 52/02: Power saving arrangements
- H04W 52/0216: {using a pre-established activity schedule, e.g. traffic indication frame}
- H04W 68/00: User notification, e.g. alerting and paging, for incoming communication, change of service or the like
- H04W 68/02: Arrangements for increasing efficiency of notification or paging channel
- H04W 76/28: Discontinuous transmission [DTX]; Discontinuous reception [DRX]
- H04W 88/12: Access point controller devices
- H04W 92/06: between gateways and public network devices
- H04W 88/16: Gateway arrangements
- Y02D 30/70: in wireless communication networks
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE

## Abstract

The present disclosure is directed to providing a gateway device that can properly page a communication terminal managed by a control device even if the control device loses information on the communication terminal when the control device recovers from a failure that has occurred therein. A gateway device (10) according to the present disclosure includes a storage unit (11) configured to store temporarily allocated identification information temporarily allocated to a communication terminal and an eDRX parameter associated with the communication terminal, and a transceiver (12) configured to, in a case in which downlink data destined for a communication terminal managed by a mobility management device (20) is received after a failure has occurred in the mobility management device (20), transmit a notification message with the temporarily allocated identification information and the eDRX parameter set therein to the mobility management device (20) or another mobility management device (21).

## Claims

### Claim 1

A gateway device that operates as a Serving Gateway (SGW) and communicates with a mobility management device which is operable to be a Mobility Management Entity (MME) and to manage a communication terminal configured to execute a paging procedure with a power saving feature, the SGW comprising:
at least one memory storing instructions; and
at least one processor configured to execute the instructions to:
when the MME has failed and downlink data is received for the communication terminal when using the power saving feature, buffer, by the SGW, the received downlink data for an extended duration until next occasion after a restart of the MME;
detect the restart of the MME; and
when the restart of the MME is detected, transmit, by the SGW, a Downlink Data Notification message including an identifier of the communication terminal to another mobility management device, if there is downlink data buffered for the communication terminal.

### Claim 2 (depends on 1)

The gateway device according to claim 1, wherein the identifier of the communication terminal is an International Mobile Subscriber Identity (IMSI).

### Claim 3 (depends on 1)

The gateway device according to claim 1, wherein the communication terminal is a User Equipment (UE).

### Claim 4

A method of controlling a gateway device that operates as a Serving Gateway (SGW) and communicates with a mobility management device which is operable to be a Mobility Management Entity (MME) and to manage a communication terminal configured to execute a paging procedure with a power saving feature, the method comprising:
when the MME has failed and downlink data is received for the communication terminal when using the power saving feature, buffering, by the SGW, the received downlink data for an extended duration until next occasion after a restart of the MME;
detecting the restart of the MME; and
when the restart of the MME is detected, transmitting, by the SGW, a Downlink Data Notification message including an identifier of the communication terminal to another mobility management device, if there is downlink data buffered for the communication terminal.

### Claim 5 (depends on 4)

The method according to claim 4, wherein the identifier of the communication terminal is an International Mobile Subscriber Identity (IMSI).