# US 10,873,883 B2 · Method and apparatus for accessing legacy networks through temporary ID of evolved network

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- Number: US 10,873,883 B2
- Document ID: US10873883B2
- Status: Granted
- Kind: B2
- Application number: 15/819,176
- Filed: 2017-11-21
- Published: 2018-11-01
- Granted: 2020-12-22
- Earliest claimed: 2007-11-01
- Assignees: Huawei Technologies Co., Ltd.
- Applicants: Huawei Technologies Co., Ltd.
- Inventors: Xiaolong Guo
- Web page: https://patentgrep.com/patent/US10873883B2

## CPC

- H04W 36/0033: {with transfer of context information}
- H04L 61/4588: containing mobile subscriber information, e.g. home subscriber server [HSS]
- H04W 8/26: Network addressing or numbering for mobility support
- H04W 36/10: Reselecting an access point controller
- H04W 74/00: Wireless channel access
- H04W 88/005: {Data network PoA devices}
- H04W 88/14: Backbone network devices
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

In a method for accessing a legacy wireless network, a radio access network (RAN) node in the legacy wireless network receives an access message sent by a User Equipment (UE) attempting to access the legacy wireless network. The access message includes mobility management entity (MME) information identifying an MME accessed by the UE in an evolved network. The MME information is added by the UE from a temporary identity (ID) allocated by the MME to a first P-Temporary Mobile Station Identity (P-TMSI) in the access message. The RAN node selects a corresponding Serving GPRS Support Node (SGSN) in the legacy wireless network for the UE according to the first P-TMSI in the access message.

## Claims

### Claim 1

A method for retrieving User Equipment (UE) context, the method comprising:
receiving, by a Mobility Management Entity (MME) in an evolved network, a Routing Area Identification (RAI), a P-Temporary Mobile Station Identity (P-TMSI) and a P-TMSI signature from a Serving GPRS Support Node (SGSN) in a 2G/3G network, wherein the RAI, P-TMSI and P-TMSI signature are mapped from a temporary identity (ID) for identifying a UE in the evolved network;
obtaining, by the MME, the temporary ID according to the RAI, P-TMSI and P-TMSI signature; and
returning, by the MME, a UE context corresponding to the UE according to the obtained temporary ID.

### Claim 2 (depends on 1)

The method of claim 1, wherein an MME-Identity (MME-id) for identifying an MME within a pool is mapped from the temporary ID to the P-TMSI.

### Claim 3 (depends on 2)

The method of claim 2, wherein the MME-id is mapped from the temporary ID to a Network Resource Identifier (NRI) field of the P-TMSI.

### Claim 4 (depends on 3)

The method of claim 3, wherein a pool-id for identifying a pool the MME belongs to is mapped from the temporary ID to a Location Area Code (LAC) field of the RAI.

### Claim 5 (depends on 4)

The method of claim 4, wherein a Public Land Mobile Network-Identity (PLMN-id) from the temporary ID is mapped to a Mobile Country Code (MCC) field and a Mobile Network Code (MNC) field of the RAI.

### Claim 6 (depends on 5)

The method of claim 5, wherein an M-TMSI from the temporary ID is mapped to the P-TMSI and the P-TMSI Signature.

### Claim 7 (depends on 6)

The method of claim 6, wherein the MME-id is further mapped from the temporary ID to a Routing Area Code (RAC) field of the RAI.

### Claim 8 (depends on 1)

The method of claim 1, wherein the temporary ID is an SAE-TMSI, wherein the SAE-TMSI is longer than the P-TMSI.

### Claim 9

A network equipment, comprising:
a receiver configured to receive a Routing Area Identification (RAI), a P-Temporary Mobile Station Identity (P-TMSI) and a P-TMSI signature from a Serving GPRS Support Node (SGSN) in a 2G/3G network, wherein the RAI, P-TMSI and P-TMSI signature are mapped from a temporary identity (ID) for identifying a User Equipment (UE) in an evolved network; and
a processor configured to obtain the temporary ID according to the RAI, P-TMSI and P-TMSI signature, and return a UE context corresponding to the UE according to the obtained temporary ID.

### Claim 10 (depends on 9)

The network equipment of claim 9, wherein an MME-Identity (MME-id) for identifying a Mobility Management Entity (MME) within a pool is mapped from the temporary ID to a Network Resource Identifier (NRI) field of the P-TMSI.

### Claim 11 (depends on 10)

The network equipment of claim 10, wherein a pool-id for identifying a pool the MME belongs to is mapped from the temporary ID to a Location Area Code (LAC) field of the RAI.

### Claim 12 (depends on 11)

The network equipment of claim 11, wherein a Public Land Mobile Network-Identity (PLMN-id) from the temporary ID is mapped to a Mobile Country Code (MCC) field and a Mobile Network Code (MNC) field of the RAI.

### Claim 13 (depends on 12)

The network equipment of claim 12, wherein an M-TMSI from the temporary ID is mapped to the P-TMSI and the P-TMSI Signature.

### Claim 14 (depends on 9)

The network equipment of claim 9, wherein the temporary ID is an SAE-TMSI, wherein the SAE-TMSI is longer than the P-TMSI.

### Claim 15

A communication system, comprising: a Mobility Management Entity (MME) in an evolved network and a Serving GPRS Support Node (SGSN) in a 2G/3G network,
wherein the SGSN is configured to send a Routing Area Identification (RAI), a P-Temporary Mobile Station Identity (P-TMSI) and a P-TMSI signature to the MME, and the RAI, P-TMSI and P-TMSI signature are mapped from a temporary identity (ID) for identifying a User Equipment (UE) in the evolved network; and
the MME is configured to receive the RAI, P-TMSI and P-TMSI signature, to obtain the temporary ID according to the RAI, P-TMSI and P-TMSI signature, and to return a UE context corresponding to the UE according to the obtained temporary ID.

### Claim 16 (depends on 15)

The communication system of claim 15, wherein an MME-Identity (MME-id) for identifying a Mobility Management Entity (MME) within a pool is mapped from the temporary ID to a Network Resource Identifier (NRI) field of the P-TMSI.

### Claim 17 (depends on 16)

The communication system of claim 16, wherein a pool-id for identifying a pool the MME belongs to is mapped from the temporary ID to a Location Area Code (LAC) field of the RAI.

### Claim 18 (depends on 17)

The communication system of claim 17, wherein a Public Land Mobile Network-Identity (PLMN-id) from the temporary ID is mapped to a Mobile Country Code (MCC) field and a Mobile Network Code (MNC) field of the RAI.

### Claim 19 (depends on 18)

The communication system of claim 18, wherein an M-TMSI from the temporary ID is mapped to the P-TMSI and the P-TMSI Signature.

### Claim 20 (depends on 15)

The communication system of claim 15, wherein the temporary ID is an SAE-TMSI, wherein the SAE-TMSI is longer than the P-TMSI.