JP2009147630A - Connection node, and signal transfer method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid double development of services by unifying call processing, as we say, of a mobile terminal in only an IMS network in the case in which two communication networks, a 3G network and an IMS network, coexist. <P>SOLUTION: When the two networks, the 3G network (IMT-2000 network) and the IMS network, coexist at the stage of transition from the 3G network to the IMS network, the two networks are connected and a node RUA functioning as a terminal of the IMS network is provided. By the RUA, a protocol of a call processing signal from the 3G network is terminated via a subscriber line exchanger MSC or a subscriber packet exchanger SGSN, the call processing is performed in the IMS network, and application is provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a connection node between different communication networks and a signal transfer method using the connection node, and in particular, is constructed based on an IMT-2000 system (hereinafter referred to as a 3G mobile communication network) and the 3G mobile communication network. The present invention relates to an example in which an IMS (IP Multimedia Subsystem) network coexists, and relates to a connection node and a signal transfer method that unify call processing including outgoing and incoming calls including a location registration process of a mobile terminal.

  In the current 3G mobile communication network, communication carriers provide various communication services. For example, it provides multimedia services consisting of audio, video, and data. In this case, since the mobile terminal is made / received, registration processing of the location of the mobile terminal, outgoing call processing, and incoming call processing (hereinafter, these processes are collectively referred to as call processing) are indispensable. is there. In other words, in the 3G mobile communication network, this call processing is performed each time the mobile terminal changes the area in which the mobile terminal is located or makes a call.

On the other hand, introduction of core network including IMS network that provides multimedia service on IP-CAN (IP Connectivity Access Network) communication bearer to realize IP (internet protocol) of communication network Is being realized by telecommunications carriers. In this IMS network, SIP, which is a communication protocol, is used to analyze and transfer a SIP signal and cooperate with an Internet application or content to provide a service (see Non-Patent Document 1). Also in this case, for the mobile terminal, the above-described so-called call processing is performed every time the service area is changed or every time a call is made or received.
Series: IMS (1)-(8), the core of NGN [Searched on November 6, 2007] Internet <URL: {http://wbb.forum.impressrd.jp/feature/20060720/165}>

  By the way, when introducing an IMS network aiming at IP, a situation occurs in which both the 3G mobile communication network and the IMS network coexist at the time of transition from the current 3G mobile communication network to the IMS network. In this situation, not only communication within the 3G mobile communication network or within the IMS network, but also communication between the 3G mobile communication network and the IMS network, that is, for example, movement within the 3G mobile communication network There may be communication between a terminal and a mobile terminal located in the IMS network.

However, the coexistence of the 3G mobile communication network and the IMS network means that the above-described call processing is performed independently for each of these networks. When these networks coexist, even if either network or both networks are used, it is necessary to provide an equal service to the user. For this purpose, particularly in consideration of provision of a new service, it is necessary to develop the same service (double development of service) for both networks, and it is necessary to provide a similar server device.
The present invention has been made to solve the above-described problems of the prior art, and an object thereof is to provide a connection node and a signal transfer method for unifying so-called call processing and avoiding double development of services. That is.

The connection node according to claim 1 of the present invention connects the first network and a second network that is established on the basis of the first network and coexists in the first network, and includes the first network including the second network. A connection node provided in the core network of the network,
Mutual conversion is performed using a termination function for terminating a control signal protocol based on the first network, a terminal function that behaves as a terminal of the second network, and a signal protocol suitable for the first network and the second network. Conversion function to be performed.
According to such a configuration, the connection node functions as a proxy for a terminal located in the first network, and call processing can be executed on the second network, so that call processing can be unified.

The connection node according to claim 2 of the present invention is the connection node according to claim 1, wherein the first network is a 3G mobile communication network and the second network is an IMS network.
According to such a configuration, it is possible to unify call processing between communication networks that are currently most needed.
The connection node according to claim 3 of the present invention is the connection node according to claim 2, wherein a NAS signal transfer path that passes through the subscriber switch is formed with the subscriber switch of the 3G mobile communication network, The mutual conversion of the signal protocol by the conversion function is a mutual conversion between SIP and NAS.
According to such a configuration, the NAS signal can be transmitted and the call processing can be unified by the signal conversion between NAS and SIP, which depends on the software change. Therefore, there is no need to add or significantly change hardware such as server device replacement or expansion.

The connection node according to claim 4 of the present invention is the connection node according to claim 3, wherein whether to connect to a subscriber switch or a subscriber packet switch of the 3G mobile communication network is distinguished by a protocol. Features.
According to such a configuration, it is easy to determine a received signal by distinguishing protocols.
A connection node according to claim 5 of the present invention is the connection node according to any one of claims 1 to 4, wherein the control signal relates to location registration of a mobile terminal located in a 3G mobile communication network. It is a signal.
According to such a configuration, location registration processing can be performed in call processing.

A connection node according to claim 6 of the present invention is the connection node according to any one of claims 1 to 4, wherein the control signal is a part of call processing of a mobile terminal located in a 3G mobile communication network. It is a signal related to transmission processing.
According to such a configuration, it is possible to perform call processing in call processing.
A connection node according to claim 7 of the present invention is the connection node according to claim 6, wherein a control signal to the subscriber exchange is transmitted along with transmission of the INVITE signal to the communication partner terminal based on the signal related to the call processing. An RAB extension path is formed with the subscriber exchange as a trigger.
According to such a configuration, RAB (sometimes referred to as RAB bearer) can be set by a trigger from the connection node.

The connection node according to claim 8 of the present invention is the connection node according to any one of claims 1 to 4, wherein the control signal is accompanied by paging to a mobile terminal located in a 3G mobile communication network. It is a signal related to incoming call processing.
According to such a configuration, an incoming call process among the call processes can be performed.
The connection node according to claim 9 of the present invention is the connection node according to claim 8, wherein a control signal to the subscriber exchange is triggered upon reception of the incoming call setting confirmation signal based on the signal related to the incoming call processing. A RAB extension path is formed with the subscriber exchange.
According to such a configuration, the RAB bearer can be set by a trigger from the connection node.

A signal transfer method according to claim 10 of the present invention includes a step of transmitting a location registration request signal from a mobile terminal that has moved into an area of a 3G mobile communication network to a subscriber exchange (corresponding to the flow of signal S1 in FIG. 1); A protocol of the location registration request signal passing through a C-plane transfer path formed between the subscriber exchange and a connection node disposed in a core network including the IMS network, Terminating at the connection node and converting the signal into a SIP signal (corresponding to the flow of signals S2 and S3 in FIG. 1), and on the IMS network based on the SIP signal converted by the connection node Performing a location registration process for the mobile terminal (corresponding to the flow of signals S4 and S5 in FIG. 1).
According to such a configuration, the location registration process can be performed on the IMS network by the connection node as a proxy for the mobile terminal that has moved to the 3G mobile communication network, and the location registration process on the IMS network can be unified.

A signal transfer method according to an eleventh aspect of the present invention includes a step of exchanging a signal for starting transmission processing between a mobile terminal located in an area of a 3G mobile communication network and a subscriber exchange (signal of FIG. 5). S51, S52, and S53)) and the call processing that has passed through the C-plane transfer path formed between the subscriber exchange and the connection node arranged in the core network including the IMS network. A signal protocol for starting is terminated at the connection node that behaves as a terminal of the IMS network, and the signal is converted into a SIP signal (corresponding to the flow of the signal S54 in FIG. 5), and converted by the connection node. A step of identifying a communication partner for the mobile terminal on the IMS network based on the received SIP signal (corresponding to the flow of signals S55, S56, S57, and S58 in FIG. 5), and the connection no Transmitting a trigger signal to the subscriber exchange to set a bearer on the calling side (corresponding to the signal flow of signals S61, S63, and S64 in FIG. 6).
According to such a configuration, the connection node functions as a proxy for the mobile terminal located in the 3G mobile communication network, so that it is possible to perform transmission processing on the IMS network and unify transmission processing on the IMS network. Can be achieved.

A signal transfer method according to a twelfth aspect of the present invention includes a step of exchanging a signal for starting an incoming call processing between a mobile terminal located in an area of a 3G mobile communication network and a subscriber exchange (signal of FIG. 11). S111, S112, corresponding to the signal flow of signals S121 and S122 in FIG. 12) and the transfer of the C-plane formed between the subscriber exchange and the connection node arranged in the core network including the IMS network After exchanging a signal for starting the incoming call processing that terminates the protocol at the connection node that passes through the path and behaves as a terminal of the IMS network, a trigger signal is sent from the connection node to the subscriber exchange. And a step of setting a bearer on the receiving side (corresponding to the signal flow of the signals S141, S143, and S144 in FIG. 14).
According to such a configuration, incoming call record processing can be performed on the IMS network by the connection node as a proxy for the mobile terminal located in the 3G mobile communication network, and the incoming call processing on the IMS network can be unified. .

  According to the present invention, when the first communication network and the second network constructed on the basis of the first communication network coexist, the control signal based on the first communication network is on the core network including the second network. By providing a connection node having a terminal function that performs the protocol termination function of the second network, has a terminal function that behaves as a terminal of the second network, and has a conversion function that performs mutual conversion of signals suitable for the first communication network and the second network. The so-called call processing of mobile terminals located in one communication network can be executed collectively in the second network, and service development need only be performed for the second network.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings referred to in the following description, the same parts as those in the other drawings are denoted by the same reference numerals.
The present invention provides a solution for performing so-called call processing uniformly and collectively in the second network when the first communication network and the second network constructed on the basis of the first communication network coexist. To do. As a specific embodiment, a 3G mobile communication network is used as the first communication network, and an IMS network is used as the second communication network.
In the following description, call processing in the 3G mobile communication network alone or call processing in the IMS network alone will be described as necessary. Call processing focused on communication with mobile terminals residing in the IMS network will be described.

(Embodiment)
<Location registration procedure for CS>
FIG. 1 is a block layout diagram regarding a location registration procedure for circuit switching (hereinafter also referred to as CS (circuit switching)) using a connection node according to an embodiment of the present invention. Referring to the figure, the lower side of the broken line L that bisects the figure shows the radio address network N1 including the 3G mobile communication network, and the upper side of the broken line L indicates the core network N2 including the IMS network. The wireless address network N1 includes a 3G area that is a location registration area of the 3G mobile communication network. In this area, a mobile terminal 1A (hereinafter referred to as UE1A (user equipment 1A)) is present. The UE 1A is wirelessly connected to a radio base station (not shown) located in the mobile terminal 1A. Further, this radio base station is connected to a radio network controller (hereinafter referred to as RNC (radio network controller)) having a line control function by wire.

  In FIG. 1, the core network N2 including the IMS network above the broken line L is connected to a subscriber exchange (hereinafter referred to as MSC) having functions such as recognition of a mobile terminal, acquisition of subscriber information, route change, etc. (Referred to as mobile switching center), a gateway for connecting multiple MSCs to each other (hereinafter referred to as G-MSC (gateway-mobile switching center)), and a media gateway required for network interconnection (hereinafter referred to as MGW (media gateway)) And a media gateway control function block (hereinafter referred to as MGCF (media gateway control function)) for controlling the MGW.

Note that the G-MSC and MGCF / MGW shown in FIG. 1 are necessary for establishing a RAB extension path, which will be described later, but are not directly related to this location registration procedure, so only the display of blocks is performed. The display of the broken line L, the radio address network N1, and the core network N2 in FIG. 1 is the same in the other FIGS. 4 to 6, FIG. 10 to FIG. 12, and FIG.
Further, in FIG. 1, a remote user agent (hereinafter referred to as RUA) is arranged in the core network N2. This RUA is a node that performs the termination of the protocol of the location registration signal from the 3G mobile communication network and the IMS. In the network, it is a node that acts as a terminal (represents a mobile terminal). That is, this RUA is a connection node having a mutual conversion function of signal protocols between the 3G mobile communication network and the IMS network. Further functions of call processing related to this RUA will be described later.

  The core network N2 further has a call session control function (hereinafter referred to as CSCF (call session control function)) block that performs SIP registration, transfer, application distribution, etc. for IMS service, and provides a service provision scenario and voice. It has a circuit switched application server (hereinafter referred to as CS-AS (circuit switch-application server)) that provides services, and a home location register (hereinafter referred to as HLR) or a home subscriber server (hereinafter referred to as HSS) that manages subscriber information. And).

  In the block arrangement as described above, when the UE 1A has moved to the 3G area and is in the area, first, a location registration process for registering the UE 1A in the HLR / HSS is performed. The procedure of the location registration process is also clearly shown in the sequence diagram of FIG. In the call processing including the location registration processing, attention is paid to a control signal (referred to as a NAS signal) in a NAS (network access stratum) protocol that is a control layer between the UE 1A and the MSC that is the entrance of the core network N2, and the MSC The transmitted NAS signal is transferred to RUA through a C-plane transfer path formed between the MSC and RUA.

  The procedure of the location registration process will be described below. That is, the location registration request signal S1 is output from the UE 1A to the MSC via the RNC when the UE 1A is in the area, and the MSC that has received the location registration request signal S1 at the MSC determines whether NAS transfer is possible or not J to the RUA. Done. This NAS transfer availability determination J is a determination of whether or not to transfer the location registration request signal S1 from the UE 1A to the RUA. When transferring to RUA, a C-plane transfer path is established between MSC and RUA using No. 7 common line signaling (hereinafter referred to as SS7 (signaling system No. 7)). Then, a transfer position registration signal S2, which is a position registration request signal S1 that passes through the MSC toward the RUA on this path, is transferred. In other words, the NAS signal passes through the MSC and is transferred to the RUA. In this case, the NAS transfer feasibility determination J in the MSC is performed as follows, for example. That is, when all mobile terminals (UEs) in the 3G area perform transfer position registration with RUA uniformly, the transfer is made as “transfer possible”. However, whether or not the location management registration can be transferred to the RUA may be affected by the identification of the corresponding mobile terminal or the presence / absence of a service contract between the corresponding mobile terminal and the IMS network. Note that a transfer path between the MSC and the RUA can be formed whenever necessary. Of course, when all the mobile terminals (UEs) uniformly register the transfer location with the RUA, it is possible to always form a transfer path. Here, in determining whether or not NAS transfer is possible J, the terminal identifier and subscriber profile of the corresponding mobile terminal are inquired from the HLR / HSS for determination. Furthermore, the transfer of the transfer position registration signal S2 between the MSC and the RUA is performed in a layer higher than the existing 3G mobile communication network protocol stack as shown in FIG. RUA is equipped with a protocol consisting of CC (call control), MM (mobility management) or RANAP (radio access network application part) included in NAS. In FIG. 3, SGW is a signaling gateway. However, this is not shown in FIG.

  Returning to FIG. 2, RUA is a terminal device for the transfer position registration signal S2 transferred from the MSC. The RUA receives the transfer position registration signal S2, which is the position registration request signal S1 to be transferred, terminates the NAS signal, and converts the NAS signal into a SIP signal of the IMS network. Here, termination / conversion of the NAS signal that is a control signal in the NAS protocol and SIP signal in the SIP protocol is termination / conversion of the protocol. The RUA is thus a termination device and has a signal conversion function. At the same time, this RUA behaves as a terminal device in the IMS network. That is, the RUA functions as a proxy for the UE 1A located in the 3G mobile communication network and is also a terminal device of the IMS network.

The transfer position registration signal S2 reaches the HLR / HSS through the CSCF and CS-AS in this order as a Registration request signal S3 converted into a SIP signal by the RUA. In this HLR / HSS, the location registration of the UE 1A is performed. Thus, the location registration process of the UE 1A is performed on the IMS network by the RUA that functions as a proxy for the UE 1A.
Thereafter, the signal S4 including the subscriber profile of the UE 1A registered in the HLR / HSS is downloaded to the CS-AS. Then, a Registration response signal S5 is returned from the CS-AS to the RUA via the CSCF. After the RUA signal conversion process, the transfer position registration response signal S6 is returned to the MSC through the transfer path using SS7. The location registration response signal S7 is returned from the MSC to the UE 1A via the RNC. With the above process, the location registration process on the IMS network of the UE 1A located in the 3G mobile communication network is completed.

<Location registration procedure with CS and PS added>
The block arrangement shown in FIG. 1 is an example of a block arrangement related to location registration in circuit switched CS. In contrast, FIG. 4 describes a location registration process that takes into account both circuit switching (CS) and packet switching (hereinafter also referred to as PS (packet switching)). Unlike FIG. 1, FIG. 4 has a configuration in which a serving GPRS support node (hereinafter referred to as a SGSN (serving general packet radio service support node)) that provides a packet communication service is arranged.

  When the location registration process is performed for each of the CS domain and the PS domain, the signal processing increases. Therefore, in FIG. 4, the CS side and the PS side are collectively (joined) to be processed simultaneously. In FIG. 4, the location registration request signal S41 output from the UE 1A is received as an NAS signal by the SGSN via the RNC. In this SGSN, PS domain information is obtained, and a joint location registration request signal S42 in which the CS domain and the PS domain are combined by a BSSAP + protocol different from NAS is transferred from SGSN to RUA. This joint location registration request signal S42 is converted into a SIP signal by RUA. Thereafter, the registration request signal S43 is output to the HLR / HSS via the CSCF and CS-AS as in the case of FIG. 1, and the location registration of the UE 1A is performed. In this case, CS domain information can be obtained in CS-AS. As a result, HLR / HSS allows simultaneous registration of CS domain and PS domain. Next, as in FIG. 1, the signal S44 including the subscriber profile of the UE 1A is downloaded from the HLR / HSS to the CS-AS. Then, the CS-AS returns a Registration response signal S45 to the RUA via the CSCF. After the RUA signal conversion processing, a joint location registration response signal S46 by BSSAP + protocol is returned to SGSN. The NAS location registration response signal S47 is returned from the SGSN to the UE 1A via the RNC. With the above processing, the location registration processing for both the CS domain and the PS domain is completed.

Whether the reception of the transfer position registration signal S2 from the MSC shown in FIG. 1 or the reception of the joint position registration request signal S42 from the SGSN shown in FIG. That is, NAS or BSSAP +.
Also, FIG. 4 shows a C-plane transfer path using SS7 between MSC and RUA as in FIG. This is described in FIG. 4 because the location registration process in the case of FIG. 1 can be performed in parallel, and a transfer path using SS7 can always be formed if necessary. did.

  As described above, when the UE 1A moves into the 3G area of the 3G mobile communication network, the location registration request is output from the MSC or SGSN and terminated at the RUA, and as a result of the signal conversion to the SIP at the RUA, Location registration processing on the IMS network is possible. In other words, not only the location registration of the mobile terminal on the IMS network but also the location registration processing on the IMS network included in the core network of the 3G mobile communication network is possible for the mobile terminal on the 3G mobile communication network. Unification of processing can be achieved.

<Calling procedure>
FIGS. 5 and 6 are diagrams showing a call processing procedure from the UE 1A located in the 3G area on the 3G mobile communication network in the call processing. Unlike FIG. 1, FIG. 5 shows a UE 1 </ b> B that is on the IMS network and is a communication partner. In the figure, the in-service CSCF (referred to as S-CSCF) of the UE 1B is described. 5 and 7, when the service request signal S51 is output from the UE 1A, this service request signal S51 passes through the MSC via the RNC and is received by the RUA as a NAS signal. Next, authentication and concealment processing is performed in the RUA, and an authentication and concealment processing signal S52, which is a concealment instruction signal, is transmitted from the RUA via the MSC to the UE 1A in the authentication request signal RNC.
Thereafter, the setup signal S53 is output from the UE 1A to the RUA via the MSC. In this case, the exchange of signals between the MSC and the RUA is performed on the C-plane transfer path using SS7 as in the case of FIG.

  In the RUA that has received the setup signal S53, signal conversion to SIP is performed, and the INVITE signal S54 is output to the CS-AS via the CSCF. The CS-AS confirms the location of the UE 1B that is the communication partner ( Therefore, the HSS outputs an incoming translation inquiry signal S55 indicating whether the location of the UE 1B is in the 3G area or the IMS network. That is, in the HLR, it is determined whether the UE 1B is in the 3G area or the IMS network. In FIG. 5, UE1B is located in the IMS network, and upon confirmation of the presence, the INVITE signal S56 is transmitted from the CS-AS to the CSCF, and then the UE1B is located from the CSCF to the HSS. An in-translation inquiry signal S57 is transmitted as to which S-CSCF is the serving CSCF (S-CSCF). As a result, the INVITE signal S58 is output from the CSCF to the UE 1B via the target S-CSCF.

  6 and 7, the RAB-Assignment request signal S61 is transmitted to the MSC on the C-plane transfer path using the SS7 from the RUA at the same time as or before or after the INVITE signal S58 of FIG. The RAB-Assignment request signal S62 is also output from the MSC to the RNC. A RAN-side bearer is set between the RNC and the UE 1A using the RAB-Assignment request signals S61 and S62 as a trigger, and at the same time, an RAB extension path that is a RAB bearer in the order of G-MSC-MGCF / MGW-RUA from the MSC. Establish request signal S63 is transmitted. Thereafter, an Establish confirmation signal S64 is transmitted from RUA in the order of MGCF / MGW-G-MSC-MSC, and an RAB extension path is formed between these nodes. Then, the RAB-Assignment response signal S66 is transmitted from the MSC to the RUA using the establishment confirmation signal S64 from the G-MSC and the RAB-Assignment response signal S65 from the RNC as triggers.

In this way, the RAB extension path is formed by using the RAB-Assignment request signal S61 on the C-plane transfer path from the RUA to the MSC as a trigger. By completing the transmission processing of FIG. 6 following FIG. 5, the UE 1A and UE 1B A call can be made during
FIG. 8 exemplifies the protocol stack of the RAB extension path on the C-plane. In this example, MSC-GMSC-MGW sets a path using B-ISUP (broadband ISDN user part) protocol, and MGW-RUA uses SIP protocol. Incidentally, the protocol stack of the RAB extension path of U-plane is shown in FIG. 9, and RTP (real time transport protocol) is used between MGW and RUA.

  As a result, from the CSCF shown in FIG. 5, an INVITE signal passes through UE1B, a U-plane is formed between UE1B and RUA, an RAB extension path is established between RUA and MSC, and 3G moves by the bearer setting between MSC and UE1A Communication between UE1A located in the communication network and UE1B located in the IMS network is possible. Then, the outgoing call processing is completed only on the core network including the IMS network.

<Incoming call processing procedure>
Next, an incoming call processing procedure from UE 1B located in the IMS network to UE 1A located in the 3G area will be described with reference to FIGS. As shown in the block arrangement shown in FIG. 10 and the sequence diagram shown in FIG. 13, the INVITE signal S101 is transmitted to the RUA from the S-CSCF where the UE 1B is located. Then, signal conversion is performed in the RUA, and a Paging request signal S102 is transmitted to the SGSN by the BSSAP + protocol, and a Paging signal S103 is transmitted from the SGSN to each RNC. The UE 1A is specified by the Paging signal S104 from the RNC, and the RNC where the target UE 1A in the 3G area is located is also found. Thereafter, the Paging response signal S105 is output from the UE 1A to the MSC via the RNC. This response signal S105 passes through the MSC, passes through the C-plane transfer path using SS7, and terminates at RUA.

  Next, as shown in FIGS. 11 and 13, authentication processing is performed between the UE 1A and the RUA, and an authentication request and a response signal S111 are exchanged through a C-plane transfer path using SS7. Also, the reporting processing signal S112 of the location location is exchanged between the target RNC and RUA by paging through the C-plane transfer path using SS7. Further, in FIG. 12, the setup signal S121 is transmitted from the RUA to the UE 1A on the C-plane transfer path using SS7, and the call confirmation signal S122 is transmitted from the UE 1A to the RUA.

  Further, as shown in FIGS. 14 and 16, the same RAB extension path processing as in FIG. 6 is performed. That is, using RAB-Assignment request signals S141 and S142 sent from the RUA to the MSC and from the MSC to the RNC in the C-plane transfer path using SS7, the MSC sends the G-MSC-MGCF / MGW-RUA The RAB extension path Establish request signal S143 is sequentially transmitted. Then, Establish confirmation signal S144 is transmitted in the order of MGCF / MGW-G-MSC-MSC from RUA, and the RAB extension path is established, and at the same time, the bearer on the RAN side is established. The RAB-Assignment response signal S146 is transmitted from the MSC to the RUA using the establishment confirmation signal S144 from the G-MSC and the RAB-Assignment response signal S145 from the RNC as triggers.

Thereafter, as shown in FIGS. 15 and 16, an alerting signal S151 in which a call is started on the receiving side is transmitted from UE1A to RUA on the C-plane transfer path using SS7, and from RUA to the calling side. A Ringing signal is sent out. Then, as shown in FIG. 16, a Connect signal S152 notifying that a call has been received at the receiving side is sent to the RUA, and a 200OK signal is sent from the RUA to the calling side.
As a result, the INVITE signal from UE1B shown in FIG. 10 passes through RUA, a U-plane is formed in RUA and MSC together with paging, UE1A side incoming processing is performed, and a RAB extension path is established between RUA and MSC. A bearer setting is performed between MSC and UE1A. This enables communication between UE 1A located in the 3G mobile communication network and UE 1B located in the IMS network. Then, the incoming call processing for the UE 1A located in the 3G mobile communication network can be completed only on the core network side including the IMS network.

(Signal transfer method)
The signal transfer method using the connection node described above has the following characteristics.
(1) A step of transmitting a location registration request signal from the mobile terminal that has moved into the area of the 3G mobile communication network to the subscriber exchange (corresponding to the flow of signal S1 in FIG. 1), and the subscriber exchange and the IMS network Terminate the protocol of the location registration request signal that has passed through the C-plane transfer path formed between the connection nodes arranged in the included core network at the connection node acting as a terminal of the IMS network And a step of converting the signal into a SIP signal (corresponding to the flow of the signals S2 and S3 in FIG. 1), and performing location registration processing on the mobile terminal on the IMS network based on the SIP signal converted by the connection node Step (corresponding to the flow of signals S4 and S5 in FIG. 1) Recording processing becomes possible, thereby the unification of the location registration processing on the IMS network.

  (2) Step of exchanging a signal for starting transmission processing between the mobile terminal located in the area of the 3G mobile communication network and the subscriber exchange (corresponding to the flow of signals S51, S52 and S53 in FIG. 5) ) And the protocol of the signal for starting the transmission process that has passed through the C-plane transfer path formed between the subscriber exchange and the connection node arranged in the core network including the IMS network. Terminating at the connection node acting as a terminal of the IMS network and converting the signal into a SIP signal (corresponding to the flow of the signal S54 in FIG. 5), and the IMS network based on the SIP signal converted by the connection node The step of specifying the communication partner for the mobile terminal (corresponding to the flow of signals S55, S56, S57, S58 in FIG. 5), and the trigger signal from the connection node to the subscriber exchange together with the specification of the communication partner And a step of setting a bearer on the transmission side (corresponding to the signal flow of signals S61, S63, and S64 in FIG. 6), so that the connection node is present in the 3G mobile communication network. By functioning as a proxy for mobile terminals that are in service, it is possible to perform outgoing processing on the IMS network and unify outgoing processing on the IMS network.

  (3) Step of exchanging signals for starting incoming call processing between the mobile terminal located in the area of the 3G mobile communication network and the subscriber exchange (signals S111 and S112 in FIG. 11, signal S121 in FIG. 12) , Corresponding to the signal flow of S122) and the C-plane transfer path formed between the subscriber exchange and the connection node arranged in the core network including the IMS network and the IMS network After the exchange of signals for starting the incoming call processing with the protocol terminated at the connection node acting as a terminal, a trigger signal is sent from the connection node to the subscriber exchange to set up a bearer on the called side Step (corresponding to the signal flow of signals S141, S143, and S144 in FIG. 14), so that the connecting node acts as a proxy for the mobile terminal located in the 3G mobile communication network on the IMS network. Incoming record at Management becomes possible, thereby the unification of the incoming call processing on the IMS network.

  The present invention can be used, for example, when both communication networks coexist when moving from a 3G mobile communication network to an IMS network.

It is a figure which shows arrangement | positioning of the block relevant to the position registration procedure about the circuit switching using the connection node which concerns on embodiment of this invention. It is a sequence diagram which shows the operation | movement about each block of FIG. It is a figure which shows the example of a protocol stack about the block of FIG. It is a figure which shows arrangement | positioning of the block about the modification of the position registration procedure which concerns on FIG. It is a figure which shows arrangement | positioning of the block about the transmission process using the connection node which concerns on embodiment of this invention. It is a figure which shows arrangement | positioning of the block about the RAB bearer setting of the transmission process which concerns on embodiment of this invention. It is a sequence diagram which shows the operation | movement about each block of FIG.5 and FIG.6. It is a figure which shows the protocol stack example of the RAB extension path | pass on C-plane about the block of FIG. FIG. 7 is a diagram showing an example of a protocol stack of an RAB extension path on the U-plane for the block of FIG. 6. It is a figure which shows arrangement | positioning of the block about the incoming call process (paging) using the connection node which concerns on embodiment of this invention. It is a figure which shows arrangement | positioning of the block about the incoming call process following FIG. 10 using the connection node which concerns on embodiment of this invention. It is a figure which shows arrangement | positioning of the block about the incoming call process following FIG. 11 using the connection node which concerns on embodiment of this invention. FIG. 13 is a sequence diagram showing an operation for each block in FIGS. 10, 11, and 12. It is a figure which shows arrangement | positioning of the block about the RAB bearer setting of the incoming call process using the connection node which concerns on embodiment of this invention. It is a figure which shows arrangement | positioning of the block about the incoming call final process using the connection node which concerns on embodiment of this invention. FIG. 16 is a sequence diagram showing an operation for each block of FIGS. 14 and 15.

Explanation of symbols

N1 Radio address network N2 Core network 1A 3G area side mobile terminal (UE)
1B IMS network side mobile terminal (UE)

Claims (12)

A connection node provided in the core network of the first network including the second network, and connecting the first network and the second network established on the basis of the first network and coexisting with the first network; There,
A terminal function for terminating a control signal protocol based on the first network, a terminal function that acts as a terminal of the second network, and a signal compatible with the first network and the second network. A connection node characterized by having a conversion function.   The connection node according to claim 1, wherein the first network is a 3G mobile communication network, and the second network is an IMS network.   A NAS signal transfer path that passes through the subscriber switch of the 3G mobile communication network is formed, and the mutual conversion of the signal protocol by the conversion function is the mutual conversion of SIP and NAS. The connection node according to claim 2, wherein:   4. The connection node according to claim 3, wherein whether to connect to a subscriber switch or a subscriber packet switch of the 3G mobile communication network is distinguished by a protocol.   The connection node according to any one of claims 1 to 4, wherein the control signal is a signal related to location registration of a mobile terminal located in a 3G mobile communication network.   5. The connection node according to claim 1, wherein the control signal is a signal related to an outgoing call process in a call process of a mobile terminal located in a 3G mobile communication network.   Along with transmission of an INVITE signal to a communication partner terminal based on the signal related to the call processing, a RAB extension path is formed with the subscriber switch by using a control signal to the subscriber switch as a trigger. Item 6. The connection node according to item 6.   The connection node according to any one of claims 1 to 4, wherein the control signal is a signal related to an incoming call process associated with paging to a mobile terminal located in a 3G mobile communication network.   The RAB extension path is formed with the subscriber switch by using a control signal to the subscriber switch as a trigger when receiving an incoming call setting confirmation signal based on the signal related to the incoming call processing. 8. Connection node according to 8.   Between the step of transmitting a location registration request signal from the mobile terminal that has moved into the area of the 3G mobile communication network to the subscriber exchange, and the connection node arranged in the core network including the subscriber exchange and the IMS network Terminating the protocol of the location registration request signal that has passed through the formed C-plane transfer path at the connection node acting as a terminal of the IMS network and converting the signal into a SIP signal; and Performing a location registration process for the mobile terminal on the IMS network based on the SIP signal converted by the node.   A step of exchanging a signal for starting transmission processing between a mobile terminal located in the area of the 3G mobile communication network and the subscriber exchange, and the core exchange network disposed in the core network including the subscriber exchange and the IMS network The signal protocol for starting the transmission process that has passed through the C-plane transfer path formed with the connection node is terminated at the connection node that acts as a terminal of the IMS network, and the signal is Converting to a signal; identifying a communication partner for the mobile terminal on the IMS network based on the SIP signal converted by the connection node; and specifying the communication partner from the connection node to the subscriber exchange Sending a trigger signal and setting a bearer on the calling side.   And a step of exchanging a signal for starting an incoming call processing between a mobile terminal located in the area of the 3G mobile communication network and a subscriber switch, and the core switch including the subscriber switch and the IMS network. After exchanging signals for starting the incoming call processing that passes the C-plane transfer path formed with the connection node and terminates the protocol at the connection node acting as a terminal of the IMS network And a step of transmitting a trigger signal from the connection node to the subscriber exchange to set up a bearer on the receiving side.

Images