# US 9,521,591 B2 · Communication system for LTE network

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- Number: US 9,521,591 B2
- Document ID: US9521591B2
- Status: Granted
- Kind: B2
- Application number: 14/405,871
- Filed: 2013-01-21
- Published: 2015-10-22
- Granted: 2016-12-13
- Earliest claimed: 2012-06-07
- Assignees: NEC Corporation
- Applicants: Yusuke Miyagawa; Takayuki Kido; Takuo Akimoto; Yuki Nakanishi; Yasuhiro Watanabe
- Inventors: Yusuke Miyagawa; Takayuki Kido; Takuo Akimoto; Yuki Nakanishi; Yasuhiro Watanabe
- Web page: https://patentgrep.com/patent/US9521591B2

## CPC

- H04W 68/12: Inter-network notification
- H04W 36/00226: {wherein the core network technologies comprise IP multimedia system [IMS], e.g. single radio voice call continuity [SRVCC]}
- H04W 48/18: Selecting a network or a communication service
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

When a voice call is made from or received by UE (100) that is present in both 3G femto area (101) and LTE area (103), line switching for making a voice call or receiving a voice call is performed from MME (112) to P-CSCF (108) by using a predetermined protocol.

## Claims

### Claim 1

A communication system comprising:
a Long Term Evolution (LTE) access network including a control node, an evolved Node B (eNB), and a Home evolved Node B (HeNB); and
a 3G femto network including an Internet Protocol Multimedia System (IMS) and a femto cell base station, wherein:
the IMS includes a virtual Mobile Switching Center (MSC) for causing the control node to recognize a server in the IMS as a MSC during communication with the control node;
the virtual MSC transfers and receives a message of control information for line switching with the control node during the line switching between the eNB and the femto cell base station, and between the HeNB and the femto cell base station;
the virtual MSC causes the control node to recognize the server in the IMS as the MSC by using a predetermined protocol;
the protocol is a Session Initiation Protocol (SIP);
the server is a SIP server; and
the control node includes:
an interface control unit that controls the switching interface;
a first SIP control unit that controls, by using the SIP, the line switching of the switching interface controlled by the interface control unit; and
the SIP server includes a second SIP control unit that controls the line switching by using the SIP.

### Claim 2

A communication system comprising:
a Long Term Evolution (LTE) access network including a control node, an evolved Node B (eNB), and a Home evolved Node B (HeNB); and
a 3G femto network including an Internet Protocol Multimedia System (IMS) and a femto cell base station, wherein:
the IMS includes virtual Mobile Switching Center (MSC) for causing the control node to recognize a server in the IMS as a MSC during communication with the control node;
the virtual MSC transfers and receives a message of control information for line switching with the control node during the line switching between the eNB and the femto cell base station, and between the HeNB and the femto cell base station;
the virtual MSC causes the control node to recognize the server in the IMS as the MSC by using a predetermined protocol;
the protocol is a Session Initiation Protocol (SIP);
the server is a SIP server;
the control node and the SIP server are connected to each other via a conversion server; and
the conversion server includes:
an interface control unit that controls the switching interface with the control node; and
a SIP control unit that controls, by using the SIP, the line switching of the switching interface controlled by the interface control unit with the SIP server.

### Claim 3

A control node of a Long Term Evolution (LTE) access network comprising:
an interface control unit that controls a switching interface for performing line switching from the control node to an Internet Protocol Multimedia System (IMS) with the IMS of a 3G femto network when a voice call is made from a 3G/LTE dual terminal present in both areas, namely, a communication area of the 3G femto network and a communication area of a LTE network, or when a voice call is received by the 3G/LTE dual terminal; and
a first Session Initiation Protocol (SIP) control unit that controls the line switching with the IMS by using a SIP; wherein
the IMS includes virtual Mobile Switching Center (MSC) for causing the control node to recognize a SIP server in the IMS as a MSC during communication with the control node; and
the SIP server includes a second SIP control unit that controls the line switching by using the SIP.

### Claim 4

A conversion server comprising:
an interface control unit that controls a switching interface for performing line switching from a control node to an Internet Protocol Multimedia System (IMS) of a 3G femto network with the control node of a Long Term Evolution (LTE) access network when a voice call is made from a 3G/LTE dual terminal present in both areas, namely, a communication area of the 3G femto network and a communication area of a LTE network, or when a voice call is received by the 3G/LTE dual terminal; and
a Session Initiation Protocol (SIP) control unit that controls the line switching with the IMS by using a SIP; wherein
the IMS includes virtual Mobile Switching Center (MSC) for causing the control node to recognize a SIP server in the IMS as a MSC during communication with the control node;
the control node and the SIP server are connected to each other via the conversion server.