Handover method, mobility management network element, and communications system

Patent metadata

Field	Value
Publication number	US-2020245218-A1
Application number	US-202016850547-A
Country	US
Kind code	A1
Filing date	Apr 16, 2020
Priority date	Oct 17, 2017
Publication date	Jul 30, 2020
Grant date	—

Abstract

This application relates to the field of wireless communications technologies, and in particular, to a handover method, including: receiving, by a mobility management network element of a first network, a first handover request sent by an access network, and learning that a terminal device needs to be handed over to a second network; obtaining an identifier of the terminal device based on the first handover request; determining, by the mobility management network element of the first network, a target mobility management network element of the second network based on the identifier of the terminal device; and sending, by the mobility management network element of the first network, a second handover request to the target mobility management network element of the second network, and requesting to hand over the terminal device to the second network.

First claim

What is claimed is:

1 . A handover method, comprising:
receiving, by a mobility management network element of a first network, a first handover request sent by an access network of the first network, and learning that a terminal device needs to be handed over to a second network; obtaining, by the mobility management network element of the first network, an identifier of the terminal device based on the first handover request; determining, by the mobility management network element of the first network, a target mobility management network element of the second network based on the identifier of the terminal device; and sending, by the mobility management network element of the first network, a second handover request to the target mobility management network element of the second network, and requesting to hand over the terminal device to the second network.

2 . The method according to claim 1 , wherein the determining, by the mobility management network element of the first network, a target mobility management network element of the second network based on the identifier of the terminal device comprises:
obtaining, by the mobility management network element of the first network, a usage type of the terminal device from a subscription database based on the identifier of the terminal device; and determining, by the mobility management network element of the first network, the target mobility management network element of the second network based on the usage type of the terminal device.

3 . The method according to claim 2 , wherein the determining, by the mobility management network element of the first network, the target mobility management network element of the second network based on the usage type of the terminal device comprises:
sending, by the mobility management network element of the first network to a domain name server DNS or a network repository function NRF, a query request carrying the usage type of the terminal device; and receiving target mobility management network element information of the second network returned by the DNS or the NRF.

4 . The method according to claim 1 , wherein the determining, by the mobility management network element of the first network, a target mobility management network element of the second network based on the identifier of the terminal device further comprises:
obtaining, by the mobility management network element of the first network, a target core network identifier of the second network based on the identifier of the terminal device; and determining, by the mobility management network element of the first network, the target mobility management network element of the second network based on the target core network identifier of the second network.

5 . The method according to claim 4 , wherein the obtaining, by the mobility management network element of the first network, a target core network identifier of the second network based on the identifier of the terminal device comprises:
obtaining, by the mobility management network element of the first network, slice information of the terminal device from a context of the terminal device based on the identifier of the terminal device; obtaining a correspondence between a core network identifier of the second network and the slice information; and determining the target core network identifier of the second network based on the slice information of the terminal device and the correspondence.

6 . The method according to claim 5 , wherein the obtaining a correspondence between a core network identifier of the second network and the slice information comprises:
sending, by the mobility management network element of the first network, a request message to a policy control function PCF; and receiving, by the mobility management network element of the first network, a correspondence table that is of the core network identifier of the second network and the slice information and that is returned by the PCF.

7 . The method according to claim 5 , wherein if there are a plurality of pieces of slice information of the terminal device, and the plurality of pieces of slice information of the terminal device are configured with priority information, the step of determining the target core network identifier of the second network based on the slice information of the terminal device and the correspondence comprises:
determining the target core network identifier of the second network based on slice information with a highest priority in the slice information of the terminal device and the correspondence.

8 . A handover method, comprising:
receiving, by a first mobility management network element of a second network, a request message sent by a mobility management network element of a first network, wherein the request message carries an identifier of a terminal device; obtaining a usage type of the terminal device from subscription data based on the identifier of the terminal device; determining a target core network identifier of the second network based on the usage type of the terminal device; and returning the target core network identifier of the second network to the AMF; or determining a target mobility management network element of the second network based on the target core network identifier of the second network, and returning target mobility management network element information of the second network to the AMF; or determining a target mobility management network element of the second network based on the target core network identifier of the second network, and sending the request message to the target mobility management network element of the second network.

9 . The method according to claim 8 , wherein the target mobility management network element information of the second network comprises: an identifier of the target mobility management network element, or an access address of the target mobility management network element.

10 . The method according to claim 8 , wherein the first network is a 5G network, the mobility management network element of the first network is an AMF, the second network is a 4G network, and the mobility management network element of the second network is an MME.

11 . A mobility management network element that belongs to a first network, comprising: a communications unit and a processing unit; wherein
the communications unit is configured to: receive a first handover request sent by an access network of the first network; and learn that a terminal device needs to be handed over to a second network; the processing unit is configured to: obtain an identifier of the terminal device based on the first handover request; and determine a target mobility management network element of the second network based on the identifier of the terminal device; and the communications unit is further configured to: send a second handover request to the target mobility management network element of the second network; and request to hand over the terminal device to the second network.

12 . The mobility management network element according to claim 11 , wherein
the communications unit is configured to obtain a usage type of the terminal device from a subscription database based on the identifier of the terminal device; and the processing unit is configured to determine the target mobility management network element of the second network based on the usage type of the terminal device.

13 . The mobility management network element according to claim 12 , wherein that the communications unit is configured to obtain a usage type of the terminal device from a subscription database based on the identifi

Assignees

• Huawei Tech Co Ltd

Inventors

• Wang Yuan
• Xin Yang
• Chen Zhongping

Classifications

• H04W36/324

  by mobility data, e.g. speed data · CPC title

• H04W36/00695

  using split of the control plane or user plane · CPC title

• H04W36/0022

  for transferring data sessions between adjacent core network technologies · CPC title

• H04L61/4511

  using domain name system [DNS] · CPC title

• H04W8/20

  Transfer of user or subscriber data · CPC title