KR101004697B1 - Apparatus and Method for Interfacing a Call between Local Phone Network and Femto Cells Based on WCDMA - Google Patents

Abstract

Disclosed are an interworking apparatus and a method for interworking a wideband code division multiple access (WCDMA) based femtocell with an internal telephone network. The interworking device of the present invention enables a WCDMA-based femtocell to operate as a unit cell below the premises telephone network by IP-PBX (Private Branch eXchange). The interworking device operates as a Mobile Switching Center (MSC) for the femtocell and as a SIP UA (User Agent) for the IP-PBX, corresponding to some of the signals on the Iu-CS protocol and some of the signals on the SIP protocol. Interoperate with each other in a way. Through this, the femtocell wireless terminal can receive a circuit switched service by the IP-PBX.

Interlock, Femtocell, WCDMA, IP-PBX

Description

Apparatus and Method for Interfacing a Call between Local Phone Network and Femto Cells Based on WCDMA}

The present invention relates to an interworking apparatus for interfacing a call by interworking a WCDMA based femtocell with a private branch eXchange (IP-PBX) and processing a call.

Femto Cell (Femto Cell) is a small base station that provides a mobile communication service to an area of about 100m radius is also called Home Node-B (Home Node-B). It is mainly installed in areas where shadows of the macro cell are degraded, such as homes or buildings, or in shaded areas, to compensate for the quality of mobile communication services. In particular, femtocells have an advantage of excellent mobility because they use a universal Internet line for communication with a core network, which is low in installation cost and maintenance cost and can be installed in any region where an Internet line is installed.

The femtocell or femtocell base station known to date has been considered to be installed in a public network by a public network operator or in a home of a subscriber.

However, femtocells could be installed by private network operators with private networks, such as large businesses or corporations. However, no solution has been proposed for interworking with existing private premises telephone networks and femtocells.

Disclosure of Invention An object of the present invention is to provide an interworking apparatus and a method of interworking, which processes a call by interworking a WCDMA-based femtocell with an premises telephone network by IP-PBX (Private Branch eXchange).

Another object of the present invention is to provide an interworking apparatus and a method of interworking, which enable a WCDMA-based wireless terminal to be mapped to an extension terminal that can be processed by an IP-PBX.

In order to achieve the above object, in accordance with the present invention, an interworking method for interfacing a femtocell with an premises telephone network by IP-PBX (Private Branch eXchange), and processing a call, the step of mapping the SIP-URI for the wireless terminal in the femtocell ; Receiving an outgoing call of the wireless terminal from the femtocell base station while operating in an MSC connected to a femtocell base station of the femtocell by an Iu-CS protocol; If the outgoing call is an outgoing call to the extension telephone of the wired network, converting the outgoing call into an outgoing call of the SIP-URI according to a Session Initiation Protocol (SIP) protocol and routing it to the IP-PBX; And connecting a call by converting a part of the SIP signals received from the IP-PBX into a corresponding Iu signal and routing the femtocell base station according to an incoming procedure of the local telephone.

Here, in the routing step, when the called number included in the outgoing call of the wireless terminal includes information indicating that the call is the premises telephone network call by the IP-PBX, the outgoing call is transferred to the premises telephone of the wired network. It can be determined as an outgoing call.

The routing may include converting an outgoing call into an outgoing call of the SIP-URI according to the SIP protocol by converting a setup message from the wireless terminal into an INVITE message on a SIP protocol.

According to an embodiment, 'Some of the SIP signals are converted into corresponding Iu signals' in the step of connecting the call may include a ringing message (status code 180) received from the IP-PBX as an alert message of the Iu-CS protocol. And converting the OK response received from the IP-PBX to the connection message of the Iu-CS protocol after the ringing message.

An interworking method according to another embodiment of the present invention relates to an incoming call of a wireless terminal, comprising: mapping a SIP-URI to a wireless terminal in the femtocell; Receiving an incoming call from the IP-PBX while operating as a SIP UA connected to the IP-PBX and a SIP protocol; If the incoming call is an incoming call to the SIP-URI, converting the incoming call into a paging signal to the wireless terminal according to an Iu-CS protocol and calling the wireless terminal through the femtocell base station; And converting a part of the lu signals received during the incoming procedure of the wireless terminal according to the paging signal into corresponding SIP signals and routing the call to the IP-PBX.

In the step of connecting the call, the paging response message of the wireless terminal is converted into a 'Session Proceeding' message (status code 183) of the SIP protocol and transmitted to the IP-PBX, and the PRACK message received from the IP-PBX is Converts it to a setup message and sends it to the femtocell base station. In addition, the call confirmation message CCONF transmitted by the wireless terminal in response to the setup message is converted into an OK (PRACK) message and transmitted to the IP-PBX, and the alert message received from the femtocell base station is a ringing message (status). Code 180) and transmit the IP-PBX to the IP-PBX, and the connection message of the femtocell base station may be changed to an OK (INVITE) response message and transmitted to the IP-PBX.

According to an embodiment of the present disclosure, in the interworking method of the present invention, when the voice codec of the wireless terminal is different from the voice codec of the local telephone or the IP-PBX, the codec of the other party's codec modulated voice data transmitted as the call is connected. The method may further include converting to the processable signal.

According to another embodiment of the present invention, the interworking device for interfacing the femtocell with the premises telephone network by IP-PBX to process the call, MSC (Mobile Switching Center), IWF (Interworking Function) and SIP (Session Initiation Protocol) Contains wealth.

The MSC unit is connected to the femtocell base station of the femtocell with the Iu-CS protocol as an MSC, and determines whether the originating call of the wireless terminal received from the femtocell base station is an outgoing call to the extension telephone of the wired network.

The IWF maps the SIP-URI for the wireless terminal, and converts the outgoing call into an outgoing call of the SIP-URI according to the SIP protocol when the outgoing call is an outgoing call to the local telephone.

The SIP unit is connected to the IP-PBX and the SIP protocol as a SIP UA, routes the outgoing call of the converted SIP-URI to the IP-PBX, and receives a SIP signal according to an incoming process of the extension telephone.

The IWF converts a part of the SIP signal into a corresponding Iu signal, and the MSC unit connects the call by routing to the femtocell base station.

The interworking device according to the present invention operates as a Mobile Switching Center (MSC) for a WCDMA-based femtocell and as a SIP UA (User Agent) for an IP-PBX, and some of the signals on the Iu-CS protocol and the signals on the SIP protocol. Some of them may be interlocked in a manner that corresponds to each other.

Through this, the WCDMA-based femtocell can be connected to the IP-PBX based on the SIP protocol, and the circuit-switching service provided by the IP-PBX can be provided, so that the femtocell's wireless terminal is not connected to the public network service. It can be connected to a terminal of a public switched telephone network (PSTN). On the contrary, the wireless terminal existing in the femtocell is registered as an extension telephone in the IP-PBX, so that the user of the existing local telephone network telephone can access the wireless terminal of the femtocell without using the public wireless network.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the drawings.

1 is a diagram illustrating an example of a communication system including a WCDMA-based femtocell and an internal telephone network of the present invention. Referring to FIG. 1, the communication system 100 of the present invention is controlled by an IP-based local area network L1 and a femtocell base station 103 or 105 controlled by an IP-PBX (Private Branch eXchange) 101. It includes at least one femtocell (Femto Cell) (L2, L3), and the interworking device 107 for interworking the interworking telephone network (L1) and femtocell (L2, L3). The interlocking device 107 may be connected to an external core network C1.

The IP-PBX 101 of the premises telephone network L1 may provide a circuit switched service for a fixed wired telephone, a Session Initiation Protocol (SIP) telephone connected to the premises IP network, and the like. The IP-PBX 101 may be connected to the interworking device 107 through the SIP protocol to provide femtocells L2 and L3 with access to the premises telephone network. Therefore, the femtocells L2 and L3 form one purchasing telephone network together with the local telephone network L1.

The IP-PBX 101 assigns and registers extension numbers and SIP Uniform Resource Identifiers (URIs) to all the wireless terminals 121 to 127 that can receive the wireless communication service through the femtocells L2 and L3. Therefore, in terms of the IP-PBX 101, the wireless terminals 121 to 127 become SIP telephones. The wireless terminals 121 to 127 are separately assigned an extension number by the IP-PBX 101. However, the IP-PBX 101 does not know about the wireless terminals 121 to 127 and is connected to the wireless terminals 121 to 127 through an interworking device 107 which is recognized only as a SIP UA (User Agent).

SIP is an application layer signaling protocol that specifies the procedures for intelligent terminals that want to communicate on the Internet to identify each other, find their location, and create, delete, or change a multimedia communication session with each other. Separated by SIP URI.

The femtocells L2 and L3 are each operated by the femtocell base stations 103 and 105, and provide wideband code division multiple access (WCDMA) based mobile communication services for the wireless terminals 121 to 127 in the femtocell.

The femtocell base stations 103 and 105 are installed in the premises, and the coverage of the femtocells L2 and L3 may overlap all or part of the coverage of the local telephone network L1. The femtocell base stations 103 and 105 perform the functions of Node-B and the Radio Network Controller (RNC) with respect to the wireless terminals 121 to 127, and the radio terminals 121 to 127 within the femtocells L2 and L3. Provides incoming and outgoing service based on WCDMA.

The core network C1 is connected to the femtocells L2 and L3 through the interlocking device 107 or directly connected to the femtocells L2 and L3 without the interlocking device 107 to provide a wireless communication service by the public network.

In the case of the interworking device 107, the core network C1 may include an WCDMA-based IP Multimedia Subsystem (IMS) network, and an Internet Access Gateway (IAG) and an HSS for interworking with a femtocell (L2, L3). It may include a Home Subscriber Server, a Call Session Control Function (CSCF) and a Femto-AS (Application Server) for controlling SIP-based calls and sessions. The Femto-AS is connected to the CSCF and the HSS and provides the resources necessary to initiate and maintain a SIP communication link, such as a call, with the wireless terminals 121-127.

The IMS network provides IP-based voice and video telephony services to the wireless terminals 121 to 127 and includes network elements for signals and bearers.

The interlock device 107 interlocks the IP-PBX 101 and the femtocell base stations 103 and 105 of the local telephone network L1 with each other. The interworking device 107 is not only interworking between the femtocell base stations 103 and 105 and the IP-PBX 101, but also the authentication of the wireless terminals 121 to 127, the mobility management of the wireless terminals 121 to 127, and the femtocell L2. , Handoff between L3) is supported.

The interlocking device 107 of FIG. 1 will be configured and described as supporting interworking between the femtocell base stations 103 and 105 and the core network C1, but is not necessarily considered in the present invention. In other words, the interworking device 107 does not support interworking between the femtocell base stations 103 and 105 and the core network C1, and the femtocell base stations 103 and 105 directly connect to the core network C1 by a known method. Can be connected and not go through the interlock device 107.

The companion device 107 registers mobile terminal subscriber information for interworking and authentication with the IP-PBX 101 or the core network C1. The mobile terminal subscriber information includes an international mobile subscriber identity (IMSI), a PBX extension number, a SIP URI, and the like.

The interlocking device 107 is connected to the core network C1 through a secure tunnel and provides a mobile communication service to the wireless terminals 121 to 127 in the femtocells L2 and L3.

In addition, the interworking device 107 may provide simultaneous connectivity for the IMS network and the IP-PBX 101. The interworking device 107 interworks with the IP-PBX 101 based on the extension number and the SIP URI assigned to the wireless terminal, to the corresponding wireless terminals 121 to 127 existing in the femtocells L2 and L3. The extension exchange service by 101 can be provided. At this time, the wireless terminals 121 to 127 are identified by the extension number and the SIP URI mapped to the extension number. Calls between different wireless terminals 121 to 127 in the femtocells L2 and L3 below the interlocking device 107 may also be made through a circuit switching service by the IP-PBX 101.

The companion device 107 holds a mapping table in which the IMSI of the wireless terminals 121 to 127 is mapped to the SIP URI for the extension call of the IP-PBX 101. The mapping table includes a list of SIP URIs mapped to each of the wireless terminals 121 to 127 serviceable by the companion device 107.

For example, when the first wireless terminal 121 having the IMSI A performs the Location Update procedure via the first femtocell base station 103, the companion device 107 performs the IMSI of the corresponding wireless terminal 121 based on the mapping table. After extracting the SIP URI mapped to (A) (assuming = B), the SIP Register Request message is transmitted to the IP-PBX 101 based on the SIP URI (B). Accordingly, the IP-PBX 101 determines that there is a registration request from the SIP telephone whose SIP URI is B, and performs a registration procedure.

By the communication system 100 described with reference to FIG. 1, the wireless terminals 121 to 127 are connected to the premises telephone network L1 to make an extension call with the premises telephone. Here, the premises telephone includes a fixed wired telephone connected directly to the premises telephone network L1, a SIP telephone, as well as a PSTN telephone or other wireless terminals 121 to 127 connected through the premises telephone network L1.

2 is a block diagram of an interlock according to an embodiment of the present invention.

Referring to FIG. 2, the companion device 107 includes a mobile switching center (MSC) 201, a SIP unit 203, an interworking function (IWF) 205, and a transcoder 207.

The MSC unit 201 is connected to the femtocell base stations 103 and 105 through the control signal interface (Iu-CS) of the 3rd Generation Partnership Project (3GPP), and serves as a mobile switching center (MSC) for the femtocells L2 and L3. Mobility management and mobile call processing.

The MSC unit 201 processes and terminates the Iu signal according to the Iu-CS protocol from the femtocell base stations 103 and 105. However, instead of SS7 (Signaling System 7) used in the transport layer of the Iu-CS protocol between the femtocell base stations 103 and 105 and the MSC unit 201, UDP (User Datagram Protocol) or TCP (Transmission Control Protocol) Carries the application protocol Radio Access Network Application Part (RANAP) of the control plane (Plane). In addition, instead of UDP or TCP, SCTP (Stream Control Transmission Protocol) can be used that can provide high reliability and speed.

또는

의 프로토콜 구조를 가질 수 있다. 여기서, RUA는 RANAP USer Adaptation이다. Therefore, the lu signal between the MSC unit 201 and the femtocell base stations 103 and 105 is

or

It may have a protocol structure of. Here, RUA is RANAP USer Adaptation.

The SIP unit 203 is connected to the IP-PBX 101 via an IP-based SIP interface and operates as a SIP UA for the IP-PBX 101.

The IWF 205 converts the Iu signal provided from the MSC unit 201 into a corresponding SIP signal between the MSC unit 201 and the SIP unit 203 and converts the IMSI of the corresponding wireless terminal into the mapping table. The conversion is provided to the SIP unit 203. The MSC unit 201 processes the Iu signal by the control signal interface (Iu-CS) between the femtocell base stations 103 and 105, and sends a signal to the IWF 205 to be transmitted to the IP-PBX 101. to provide. Accordingly, the IWF 205 converts the received Iu signal into a corresponding SIP signal and provides it to the SIP unit 203, and the SIP unit 203 operates as a SIP UA for the IP-PBX 101, and generates a SIP signal. Transmit to IP-PBX 101. On the contrary, the SIP signal transmitted from the IP-PBX 101 to the femtocells L2 and L3 is converted into an Iu signal while passing through the sequence of the SIP unit 203, the IWF 205, and the MSC unit 201.

The IWF 205 converts the SIP URI included in the outgoing call transmitted by the IP-PBX 101 to the companion device 107 to the IMSI of the wireless terminals 121 to 127 based on the mapping table. For outgoing calls to route to IP-PBX 101, IWF 205 removes the local prefix of the called party's called number. The conversion method or interworking method of the IWF 205 will be described again below.

Transcoder 207 is connected to femtocell base stations 103 and 105 and IP-PBX 101 by Real-time Transport Protocol (RTP) of IP.

The WCDMA-based wireless terminals 121 to 127 have an AMR (Advanced Multi Rate) codec to code a voice signal. However, the SIP phone connected to the IP-PBX 101 or the rear end of the IP-PBX 101 may not have an AMR codec and may have a codec for another Voice Over Internet Protocol (VoIP). The transcoder 207 mutually converts the modulation method of the voice data due to the difference in the codecs.

The transcoder 207 receives the data coded by the AMR codec from the wireless terminals 121 to 127 and can be processed by a codec held by a phone connected to the rear end of the IP-PBX 101, for example, a VoIP codec such as g.729. Convert to a modulated signal. Of course, the voice data modulated by the VoIP codec and transmitted from the IP-PBX 101 is converted by the transcoder 207 into modulated data of the AMR codec.

Here, g.729 is a voice codec standard of the International Telecommunication Union (ITU) using an 8 kbps Code Excitation Linear Prediction (CELP) coding technique.

의 프로토콜 구조를 가지고, 연동장치(107)와 IP-PBX(101) 사이의 트래픽은 (예시)

의 프로토콜 구조를 가진다. Therefore, the traffic between the interworking device 107 and the femtocell base station 103, 105 is

Has a protocol structure, and the traffic between the interworking device 107 and the IP-PBX 101 is (example)

It has a protocol structure.

However, if the counterpart terminal has the AMR codec, traffic from the femtocell base station 103 or 105 may be directly transmitted to the counterpart terminal without passing through the transcoder 207 of the companion device 107.

When the companion device 107 receives the outgoing call of the first wireless terminal 121 from the first femtocell base station 103, it analyzes the called number included in the outgoing call and routes it to the IP-PBX 101. To judge. For example, when the interworking device 107 is connected to the core network C1, it may be routed to the IMS network. To this end, the called number for the local telephone network call may include a 'local prefix' indicating that the local telephone network call, the following shows an example.

Caller ID for purchase phone network == [local prefix] + [actual caller ID]

Here, as the 'local prefix', a code not used in the core network C1, for example, '# 8' or '* 11' may be used. According to an embodiment, the local prefix may be common to all telephones receiving line service by the IP-PBX 101, but may be differently applied to SIP telephones and wireless terminals. In addition, the actual called number may correspond to a virtual private network (VPN) extension number or a public switched telephone network (PSTN) number.

In the case of the above example, the companion device 107 may determine that the called number is to be routed to the IP-PBX 101 when the front part of the called number matches the 'local prefix'. The interworking device 107 routes the outgoing call to the IP-PBX 101 when it is determined for the premises telephone network call. Therefore, when the called number is "# 8 + VPN number (3-6 digits)" or "# 8 + 9 + PSTN number", the interworking device 107 routes the outgoing call to the IP-PBX 101. . At this time, the destination number of the outgoing call routed to the IP-PBX 101 is not included because the local prefix is removed.

Conversely, when the called number is a MDN (Mobile Directory Number) or PLMN (Public Land Mobile Network) number without a local prefix, the companion device routes the corresponding outgoing call to the IMS network.

Hereinafter, a call processing method performed by the MSC unit 201, the IWF 205, and the SIP unit 203 of the companion device 107 will be described with reference to FIGS. 3 and 4. In the following description, the first wireless terminal 121 on behalf of the plurality of wireless terminals 121 to 127 based on the first femtocell base station 103 on behalf of the femtocell and femtocell base station, except where otherwise noted. This description applies equally to other femtocells, femtocell base stations and wireless terminals.

3 and 4, the Iu signal of the first wireless terminal 121 and the companion device 107 is a direct transfer (hereinafter, referred to as 'DT') between the MSC unit 201 and the first wireless terminal 121. The message is centered on the message.

The operation between the first wireless terminal 121 and the first femtocell base station 103, which is not shown, may be described as a typical operation between the user equipment (UE) and the RNC based on the WCDMA protocol. Similarly, the operation or protocol between the first femtocell base station 103 and the companion device 107 may be described as an Iu-CS protocol between the RNC and the MSC based on the WCDMA protocol. In addition, the operation between the interworking device 107 and the IP-PBX 101 may also be described by the SIP protocol between the conventional SIP UA and the IP-PBX. However, the interworking device 107 converts a part of a series of Iu signals from the first femtocell base station 103 into a corresponding SIP signal and provides the IP femtocell base station 103 by providing the IP-PBX 101 or vice versa. ) And the IP-PBX 101 to interwork with each other.

For example, according to FIG. 3, the first femtocell base station 103 transmits a RANAP Initial UE message to the companion device 107. In the RANAP Initial UE message of the first femtocell base station 103, an RRC Connection Setup regarding allocation of a dedicated channel (DCH) transport channel is performed between the first femtocell base station 103 and the first femtocell base station 103. This is done when an Initial Direct Transfer message is received. The first femtocell base station 103 maps an Initial Direct Transfer message to a RANAP Initial UE message and transmits it to the companion device 107 (S301).

The MSC unit 201 of the interworking device 107 performs an authentication step (AuthReq / AuthRsp) according to a security procedure (Procedure) between the first femtocell base station 103, and encrypts (Encryption) and integrity (Integrity) Performs a procedure (SecurityMode) (S303).

Thereafter, the companion device 107 receives a setup message (SETUP) from the first wireless terminal 121. The setup message SETUP includes call setup information including a telephone number (called number) of the counterpart terminal to which the call is to be set (S305).

The MSC unit 201 determines whether to route to the IP-PBX 101 by analyzing whether the called number included in the setup message (SETUP) includes the local prefix, and sends the setup message (SETUP) to the IWF ( 205). The IWF 205 converts the setup message (SETUP) into an INVITE message of the SIP protocol and provides it to the SIP unit 203. The INVITE message includes a SIP-URI mapped in place of the IMSI of the first wireless terminal 121 as information on the calling terminal, and the called number includes the local prefix and only the actual called number. The SIP unit 203 transmits an INVITE message to the IP-PBX 101 to request a session (call) setup. The INVITE message includes information on the voice codec used by the first wireless terminal 121, the telephone number of the called terminal, and the like. In this way, an incoming procedure by INVITE is started between the SIP unit 203 of the companion device 107 and the IP-PBX 101 (S307).

When the companion device 107 receives the 'Session Proceeding' message (status code 183) (SessProg) from the IP-PBX 101, it changes to a 'Call Processing message (CPROC)' and transmits it to the first femtocell base station 103. The core may inform that the call is being processed (S309).

After transmitting the 'Call Processing' message (CPROC), the MSC unit 201 initiates a RAB (Radio Access Bearer) setting process with the first femtocell base station 103. In response to this process, the SIP unit 203 may send a PRACK (Provisional Acknowledgement) to the IP-PBX 101 and receive an OK response message (status code 200) from the IP-PBX 101 (S311).

When the companion device 107 receives a ringing (status code 180) from the IP-PBX 101, it determines that a call with the other party's phone is initiating and transmits an alert message (ALERT) to the first femtocell base station 103. . To this end, the IWF 205 converts the ringing message (status code 180) into an alert message (ALERT) according to the WCDMA protocol (S313).

Subsequently, when the IP-PBX 101 transmits an OK response message (status code 200) for the INVITE message in step S307 to the companion device 107, the companion device 107 connects an OK response message (status code 200). A message CONNECT is transmitted to the first femtocell base station 103. To this end, the IWF 205 converts the OK response message (status code 200) into a connection message (CONNECT) according to the WCDMA protocol (S315).

The interworking device 107 receives a connection acknowledgment message (CON_ACK) for the connection message (CONNECT) from the first femtocell base station (103), converts the ACK (INVITE) of the SIP protocol, and converts the IP-PBX (101). ) Thus, the call is opened (S317).

When the companion device 107 receives the disconnect message DISC from the first wireless terminal 121 to terminate the call, the companion device 107 converts the disconnected message DISC into BYE of the SIP protocol and provides the IP-PBX 101 to the IP-PBX 101 (S319).

Accordingly, if there is an OK response from the IP-PBX 101, the companion device 107 sends a disconnect message RELEASE to the first femtocell base station 103 (S321).

By the above method, call setup by the outgoing call of the first wireless terminal 121 is made. After the call is connected in step S317, voice data is exchanged, and when the codecs are different from each other, the companion device 107 may change a modulation method of the voice data.

According to an embodiment, between the companion device 107 and the IP-PBX 101, the companion device 107 immediately rings a ringing message (state) without an exchange of 'Session Proceeding' or a PRACK message after the INVITE message is transmitted in step S307. Code 180). Even in this case, the interlocking device 107 does not immediately perform step S313 after step S307, but performs an DT (CPROC) and RAB with the first femtocell base station 103 and then an alarm message corresponding to the ringing message. (ALERT) will be sent.

Hereinafter, a process in which the first wireless terminal 121 receives a call will be described with reference to FIG. 4.

When the companion device 107 receives the INVITE message according to the SIP protocol from the IP-PBX 101, the companion device 107 processes the INVITE message as a paging message for incoming call. The IWF 205 converts the paging message for calling the first wireless terminal 121 having the IMSI (A) corresponding to the called number (SIP URI = B) of the corresponding INVITE message into the MSC unit 201. The MSC unit 201 transmits the paging message to the first femtocell base station 103. This paging message includes information on the detected IMSI (S401).

When the companion device 107 receives an Initial UE (PRES) message, which is a paging response message transmitted by the first femtocell base station 103 in response to the paging message, the interworking device 107 receives a 'Session Proceeding' message (status) of the SIP protocol. Code 183) to transmit to IP-PBX 101. The MSC unit 201 of the interlocking device 107 performs step S303 with the first femtocell base station 103 (S403).

When the companion device 107 receives a PRACK message from the IP-PBX 101 between the INVITE message and the ringing message, the companion device 107 maps the PRACK message to a setup message (SETUP) and transmits the PRACK message to the first femtocell base station 103. The call confirmation message CCONF transmitted by the first wireless terminal 121 in response to the setup message SETUP is converted into an OK (PRACK) message by the interworking device 107 and is then converted into an IP-PBX 101. It is delivered to (S405).

After the RAB setting process, the interworking device 107 that receives the alert message (ALERT) from the first femtocell base station 103 changes the alert message (ALERT) to a ringing message (status code 180) and transmits it to the IP-PBX 101. (S407).

Subsequently, the companion device 107 changes the connection message CONNECT of the first femtocell base station 103 into an OK (INVITE) response message and transmits the message to the IP-PBX 101, and sends an ACK of the IP-PBX 101. The message is connected by an incoming call of the first femtocell base station 103 by changing the message to a connect acknowledgment message CON_ACK (S409).

Subsequent call termination may be performed in the same manner as in steps S319 and S321 of FIG. 3 (S411).

In the above manner, call establishment from the IP-PBX 101 to the femtocells L2 and L3 by the interworking device 107 of the present invention is made.

3 and 4, the call setup between the first wireless terminal 121 of the first femtocell L2 and the third wireless terminal 125 in the second femtocell L3 is also performed by the IP-PBX 101. It can be done through. In this case, the outgoing call of the first wireless terminal 121 is transmitted from the first femtocell base station 103 → the interworking device 107 → the IP-PBX 101 → the interworking device 107 → the third femtocell base station 205 → the first. 2 will be sent to wireless terminal 125.

The invention can be implemented in methods, devices and systems. In addition, when the present invention is implemented in computer software, the components of the present invention may be replaced with code segments necessary for performing necessary operations. The program or code segment may be stored in a medium that can be processed by a microprocessor and transmitted as computer data coupled with carrier waves via a transmission medium or communication network.

The media that can be processed by the microprocessor include electronic circuits, semiconductor memory devices, ROMs, flash memory, electrically erasable programmable read-only memory (EEPROM), floppy disks, optical disks, and hard disks. (Hard) Includes the ability to transmit and store information such as disks, fiber optics, wireless networks, and the like. Computer data also includes data that can be transmitted over electrical network channels, optical fibers, electromagnetic fields, wireless networks, and the like.

In addition, although the preferred embodiment of the present invention has been shown and described above, the present invention is not limited to the above-described specific embodiment, the technical field to which the invention belongs without departing from the spirit of the invention claimed in the claims. Of course, various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

1 is a diagram illustrating an example of a communication system including a WCDMA-based femtocell and a local telephone network of the present invention;

2 is a block diagram of an interlock device according to an embodiment of the present invention;

3 is a flow chart provided in the description of a method for transmitting from a femtocell to a premises telephone network according to the present invention; and

4 is a flowchart provided to explain a method of receiving a call to a femtocell in a premises telephone network according to the present invention.

Claims (13)

In the interworking method of interfacing a femtocell with an internal telephone network by IP-PBX (Internet Protocol-Private Branch eXchange) to process a call, Mapping Session Initiation Protocol-Uniform Resource Identifiers (SIP-URIs) to wireless terminals in the femtocell; Receiving an outgoing call of the wireless terminal from the femtocell base station while operating as a mobile switching center (MSC) connected to a femtocell base station of the femtocell with a control signal interface (Iu-CS) protocol; If the outgoing call is an outgoing call to an extension telephone in the premises telephone network, converting the outgoing call into an outgoing call of the SIP-URI according to a SIP protocol and routing to the IP-PBX; And And converting a part of SIP signals received from the IP-PBX into a corresponding interface (Iu) signal and routing the call to the femtocell base station according to an incoming procedure of the local telephone. Interworking method between the femtocell and the local telephone network. The method of claim 1, The routing step, And analyzing the called number included in the outgoing call of the wireless terminal to determine that the outgoing call is an outgoing call to the in-house telephone of the in-house telephone network. Interworking method between the femtocell and the local telephone network. The method of claim 1, The routing step, Converting the outgoing call into an outgoing call of the SIP-URI according to the SIP protocol by converting a setup message from the wireless terminal into an INVITE message on a SIP protocol. The method of claim 1, In the step of connecting the call, The ringing message (status code 180) received from the IP-PBX is converted into an Iu-CS protocol alert message, and the OK response received from the IP-PBX after the ringing message is converted into an Iu-CS protocol connection message. Interworking method between the femtocell and the local telephone network, characterized in that for transmitting to the femtocell base station. In the interworking method of interfacing a femtocell with an internal telephone network by IP-PBX (Internet Protocol-Private Branch eXchange) to process a call, Mapping Session Initiation Protocol-Uniform Resource Identifiers (SIP-URIs) to wireless terminals in the femtocell; Receiving an outgoing call of an extension telephone in the premises telephone network from the IP-PBX while operating as a SIP UA connected to the IP-PBX and the SIP protocol; If the outgoing call is an outgoing call to the SIP-URI, converting the outgoing call into a paging signal to the wireless terminal according to a control signal interface (Iu-CS) protocol to call the wireless terminal through the femtocell base station of the femtocell. step; And Femtocell comprising the step of connecting a call by converting a part of the interface (Iu) signal received during the incoming procedure of the wireless terminal according to the paging signal to a corresponding SIP signal and routing to the IP-PBX And interworking between the local telephone network. The method of claim 5, In the step of connecting the call, The paging response message of the wireless terminal is converted into a 'Session Proceeding' message (status code 183) of the SIP protocol and transmitted to the IP-PBX. Provisional Acknowledgment (PRACK) message received from the IP-PBX is converted into a setup message and transmitted to the femtocell base station, The call confirmation message CCONF transmitted by the wireless terminal in response to the setup message is converted into an OK (PRACK) message and transmitted to the IP-PBX. The alarm message received from the femtocell base station is changed to a ringing message (status code 180) and transmitted to the IP-PBX. And a connection message of the femtocell base station is converted into an OK (INVITE) response message and transmitted to the IP-PBX. 6. The method according to claim 1 or 5, If the voice codec of the wireless terminal is different from the voice codec of the local telephone or the IP-PBX, converting the modulated voice data transmitted as the call is connected to a signal that can be processed by the other party's codec. Interworking method between the femtocell and the premises telephone network. In the interworking device that processes the call by interworking the femtocell with the premises telephone network by Internet Protocol-Private Branch eXchange (IP-PBX), A mobile switching center (MSC) is connected to a femtocell base station of the femtocell with a control signal interface (Iu-CS) protocol, and receives an outgoing call of a wireless terminal in the femtocell from the femtocell base station, and the received outgoing call is connected to the local telephone network. An MSC unit for determining whether the call is an outgoing call to the extension telephone; IWF which maps Session Initiation Protocol-Uniform Resource Identifiers (SIP-URI) to the wireless terminal and converts the outgoing call into an outgoing call of the SIP-URI according to the SIP protocol when the outgoing call is an outgoing call to the extension telephone. (Interworking Function); And A SIP unit connected to the IP-PBX and the SIP protocol as a SIP UA (User Agent), routing the outgoing call of the converted SIP-URI to the IP-PBX, and receiving a SIP signal according to an incoming call of the local telephone. Including; The IWF converts a part of the SIP signal into a corresponding interface (Iu) signal, and the MSC unit connects the call by routing to the femtocell base station. The method of claim 8, The MSC unit, A femtocell, characterized in that it is determined that the outgoing call is an outgoing call to the premises telephone when the caller's number included in the outgoing call of the wireless terminal is analyzed and includes information indicating that the outgoing telephone network call is made by the IP-PBX; Interlocking devices between the premises telephone network. The method of claim 8, The IWF is, And converting the outgoing call into an outgoing call of the SIP-URI according to a SIP protocol by converting a setup message from the wireless terminal into an INVITE message on a SIP protocol. The method of claim 8, The IWF is, The ringing message (status code 180) received from the IP-PBX is converted into an alert message of the Iu-CS protocol, and the OK response received from the IP-PBX after the ringing message is converted into a connection message of the Iu-CS protocol. Interworking device between the femtocell and the local telephone network. In the interworking device that processes the call by interworking the femtocell with the premises telephone network by Internet Protocol-Private Branch eXchange (IP-PBX), A SIP unit connected to the IP-PBX and the SIP protocol as a SIP UA (Session Initiation Protocol User Agent) and receiving an outgoing call of the premises telephone in the premises telephone network from the IP-PBX; A SIP-URI is mapped to a wireless terminal in the femtocell, and when the originating call is an originating call to the Uniform Resource Identifiers (SIP-URI), the originating call is transmitted to the wireless terminal according to a control signal interface (Iu-CS) protocol. An interworking function (IWF) for converting to a paging signal; And A MSC unit connected to a femtocell base station of the femtocell with an Iu-CS protocol as a mobile switching center (MSC), and transmitting the paging signal to the femtocell base station to perform an incoming procedure of the wireless terminal; The IWF converts a part of an interface (Iu) signal according to an incoming call of the wireless terminal into a corresponding SIP signal, and the SIP unit connects the call by routing to the IP-PBX. Interlock. The method according to claim 8 or 12, wherein When the voice codec of the wireless terminal is different from the voice codec of the local telephone or the IP-PBX, a transcoder for converting the modulated voice data transmitted as the call is connected into a signal that can be processed by the other party's codec. Interworking device between the femtocell and the local telephone network, characterized in that it further comprises.

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