MX2014014406A - Internetworking for circuit switched fallback-network initiated ussd request/notification procedure mobile-terminated location request procedure provide subscriber information procedure. - Google Patents

Abstract

A method for switch user equipment from a Long Term Evolution system to a Circuit Switched system when receiving a voice call is disclosed. The method may comprise: receiving, at an IWF (Internet Working Function) network node, a Mobility Application Part Unstructured Supplementary Service Data (MAP USSD) message identifying a User Equipment (UE) originated from a USSD application, the UE associated with a first Mobile Switching Center (MSC); initiating Circuit Switched Fallback (CSFB) by sending a paging request to the UE; receiving a Cancel Location message associated with the UE from a Home Location Register (HLR) indicative of the UE being associated with a second MSC; forwarding the MAP USSD message to the UE via the HLR and the second MSC; receiving a MAP USSD response message from the UE via the HLR; and forwarding the MAP USSD response message to the USSD application.

Description

INTERNET WORK FOR SERVICE INTERRUPTION OF SWITCHED CIRCUIT NETWORK INITIATED BY PROCEDURE DE SO LIC ITUD / NOTI FIC ACION DE USSD. MOBILE FINISHED LOCATION REQUEST PROCEDURE PROVIDES SUBSCRIBER INFORMATION PROCEDURE COUNTRYSIDE The present description refers to the field of telecommunications, more particularly to Internet work for interruption of circuit switched service.

BACKGROUND Currently, Long Term Evolution (LTE) systems do not support voice calls, so the Switched Circuit Service Interruption (CSFB) specified by 3GPP TS23.272 standards is executed for these armies. The function of CS service interruption and SMS message delivery (short message system) through the CS core network is performed by using Gs interface mechanisms as defined in 3GPP TS 29.018 at the interface between the MME ( mobility management entity) and EPS (evolved package system) and VLR (visitor location registration).

This interface is called the SGs interface.

For example, the network is enhanced to call the mobile over the LTE radio, and when an LTE radio field mobile receives a voice call search request over the LTE system, the mobile device interrupts service to the CS radio to receive voice call. In connection with CSFB, active data session on PS (switched packet) 2G / 3G access is suspended or distributed. For mobile origin (MO) calls, mobile devices or user equipment (UE) camped on the LTE radio initiated service interruption by itself to originate a voice call in the CS domain. Mobiles camped on LTE radio can send and receive SMS messages without interruption of service. The basic idea is to force the UE to interrupt service to CS radio for voice calls, which is not VoLTE (voice over LTE). In order to run the CSFB, a new interface, called SGs, is required between MME (mobility management entity) and MSC / VLR (Mobile switching center / visitor location register) to allow the MSC to know when an UE it is fixed to EPC (evolved package core). The MSC / VLR is registered with the HLR (home location register) as normal, so that mobile voice calls (MT) and SMS messages are routed there. In these cases, the SMS messages of MO / MT are delivered over LTE and EPC access through MSC. For MO calls, the UE interrupts the service to the CS radio before the call originates so that core network changes are not required. For MT calls, the call is delivered to the MSC as normal, and the MSC b uses the UE through the new interface SGs between MME and MSC. The UE interrupts the service to the CS radio and already emits a Location Update or Page Response. The MSC completes the call. If the UE interrupts the service even if the MSC is different from the one that issued the SG page, complex "roaming" procedures are required to complete the call. That is, this process requires new interfaces and modification of existing nodes in each of the LTE and CS systems. The new SG interface is required between the MSC in the core network CS and the MME in the EPC. The SG allows the MSC to learn about EPC fixation. SMS of MO / MT during EPC fixation, and MSC to search the subscriber on EPC and LTE access for voice calls. As for the modified nodes, the MSC requires SG interface and associated state machine. The MME requires an interface and modification of SGs of the associated state machine and requires an S3 interface for SGSN if ISR (reduction of signaling of inactive mode) is enabled. The MSC / HLR / GMSC all require changes in order to support Roaming Retry, which is made more likely with CSFB.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a simplified block diagram of one mode of a communication system for circuit switched service interruption; Figures 2A-2I are simplified block diagrams of communication system modalities that illustrate signaling during circuit interruption service interruption; Figures 3A-1, 3A2 and 3B-1, 3B-2 are a call flow diagram illustrating one embodiment of a circuit switched service interruption procedure; Figure 4 is a flow chart illustrating an illustrative method for executing switched circuit service interruption; Figure 5 is a call flow diagram illustrating one mode of a new network initiated USSD request procedure; Figure 6 is a simplified block diagram of an illustrative embodiment of a communication system; Figure 7 is a call flow diagram illustrating a modality of a new mobile termination location reporting procedure (MT-LR); Y Figure 8 is a call flow diagram illustrating a modality of a new provision subscriber information, service interruption to the CS procedure.

DETAILED DESCRIPTION Figure 1 is an illustrative communication system 100 for switching a user equipment (UE) of a long-term evolution system (LTE) to a circuit switched (CS) system when receives a voice call For example, when the UE is encamped in an LTE system and receives an indication of a mobile termination voice call from the CS domain, the UE can switch to a CS network (2G or 3G) to accept the call. In general, the switching of the LTE network to the CS network for voice calls is indicated as Switched Circuit Service Interruption (CSFB). In some implementations, the system 100 may execute stand-alone CSFB or without including an SGs interface in a mobile switching center (MSC). In addition, the system 100 can execute the independent CSFB or without modifying the existing MSC. For example, the system 100 may include an Internet Work Function of CSFB (IWF) 102 (discussed in more detail below) that connects to a CS network through MAP interfaces and connects to an LTE network through of an SGs interface. In doing so, system 100 can eliminate, reduce, or otherwise prevent the following: changes in the MSC (eg, without SGs interfaces in the MSC, without configuration changes); roaming retry (for example, saves on complex MSC / HLR functionality, reduces call configuration delay); allocation of TA to LA (for example, all TAs can be assigned to an individual LA, owned by the CSFB and WS); which processes the MT call bearer (for example, without bearer trunk, reduce costs); and / or others.

At a high level, the system 100, in some implementations, includes the CSFB IWF 102 communicatively coupled to a CS 104 system, an LTE system 106, an UE 108 through the networks 104 and 106. The CS system 106 includes a radio access network (RAN) 1 10 and a cellular core network 1 12, and the LTE system 106 includes a LTE Radio Access Network 1 14 such as UTRAN evolved (E-UTRAN 1 14 ) and a core network 14 called an Evolved Packet Core (EPC) 1 16. Cell core network 1 12 includes GMSC 1 18, HLR 120, MSC / VLR 122, and SGSN 124. EPC 1 16 includes the MME 126 and the Home Subscriber Server (HSS) 128. As for a high level description, the CSFB IWF 102 registers with the service MSC / VLR when the UE performs an IMSI fixation on EPC 116. After registration, GMSC 1 18 may receive an incoming request to terminate a voice call with the UE and transmit a request to route information to the HLR 120. After determining that the CSFB IWF 102 is present as the MSC of service to the cellular core network 1 12, the HLR 120 can transmit a request for the MSRN to the CSFB IWF 102. In connection n with storing information identified with the request, the CSFB IWF 102 transmits a request to the UE 108 via the MME 126 of the EPC 1 16 to interrupt the service to the cellular system 104. The UE 108 can transmit a request to the MSC / VLR 122 through RAN 1 10 to update your location, which is delayed to the HLR 120. The HLR 120 reassigns the MSC / VLR 122 as the service MSC and transmits a Location Request of Cancel Location to the CSFB IWF 102. The CSFB IWF 102 sends a new request to route information to the HLR 120 and transmits the MSRN received in the PRN Recognition (Ack) GMSC 1 18, which uses this MSRN to route the call to the MSC / VLR 122 where it is completed.

Switching to the more detailed description of the system 1 10, the CSFB IWF 102 may include any software, hardware, and / or operable firmware for transferring a UE 108 from the LTE system 106 to the system CS 104 in connection with receiving a request for mobile termination by a voice call from the cellular core network 1 12. For example, the CSFB IWF 102 can search the UE 108 to request a request to update location with the HLR 120 in the cellular core network 1 12. By updating the location in the cellular system 104, the CSFB IWF 1 02 can respond to the PRN request using the MSRN that the cellular system 104 assigns during the location update. Upon starting the updated location, the CSFB IWF 102 can initiate the UE 108 to interrupt CS radio service for voice calls, which is not voice over LTE (VoLTE). In some implementations, the CSFB IWF 102 may include a new interface (SGs) to MME 126, which may allow the CSFB IWF 102, when operating with the MSC / VLR, to determine when a UE 108 is attached to the EPC 1 16. The CSFB IWF 102 may include interfaces such as SGs to MME 126, MAP to HLR 120, MAP to SMSC, and / or others. As for the SGs to MME 126, the CSFB IWF 102 can execute functionality of standard SGs, and / or the MME 126 can identify the CSFB IWF 102 as a Visitor Location Register (VLR). In other words, the CSFB IWF 102 can support the SGs interface of the MME 126 in the EPC domain. In these cases, the CSFB IWF 102 can appear as a VLR to the MME 126. The CSFB IWF 102 that acts as VLR / MSC for the subscribers in the EPC domain can interact with the HLR 120 through a MAP interface and also with an SMSC in the network 1 12 for procedures related to SMS. The CSFB IWF 102 may contain a "VLR" which maintains the states of SGs and state machine defined in 3GPP TS 29.1 18. As for the MAP for HLR 120, the CSFB IWF 102 may perform location update procedures and / or call routing procedures using this interface. The MAP interface between the CSFB IWF 102 and HLR 120 can be used for location management, subscriber management and / or call handling procedures. As for the MAP for the SMSC, the CSFB IWF 102 can execute SMS procedures of MO / MT using Short Message forward of MAP MO and / or Short Forward message of MAP MT. For example, the MAP interface between CSFB IWF 102 and an SMSC can be used for SMS originating in mobile and / or terminated in mobile. In some implementations, the CSFB IWF 102 can operate stand-alone or without bearer facilities (eg, TDM trunks). The CSFB IWF 102 can execute one or more of the following: receive the call signaling MT of the HLR 120, since it appears as the service MSC / VLR; send SG Search Request to activate CSFB; initiate MT call signaling to redirect the call to the new service (and actual) MSC / VLR; and / or other functions. In connection with these processes, the UE 108 may interrupt the service to the CS domain and may perform a Location Update MSC / VLR 122. In addition, the UE 108 may g accept the call once the CSFB IWF 102 redirects it. As previously mentioned, the IWF CSFB 102 may, in some implementations, emulate or otherwise be represented as a core network element 1 12. For example, the CSFB IWF 102 may emulate or otherwise be represented as an MSC, a VLR, or other element of the cellular core network 1 12. In the case that the communication node 108 emulates an MSC, the CSFB IWF 102 can be queried by the HLR 120 in the cellular core network 1 12 as another MSC.

By changing to a detailed description of these elements in system 100, LTE system 106 may include EPC 1 12 and E-UTRAN 1 14. EPC 6 6 provides connectivity to an external network such as cellular core network 1 12 The E-UTRAN 1 14 includes one or more base stations such as eNode-B (eNB) base stations that provide wireless service (s) to UE 108. A core network based on EPC may include a Service Access (SGW). ), the MME 126, and a Package Access (PGW). An SGW can route traffic within the EPC 1 16. The MME 1 15 is responsible for core network mobility control, attachment to the UE 108 to the core network and for maintaining UE contact inactive. The PGW is responsible for allowing the entry / exit of traffic to / from the Internet. The PGW can distribute IP addresses to the UE 108.

A wireless communication system based on LTE has network interfaces defined between system elements. Network interfaces include the Uu interface defined between a UE and a eNB, the user plane interface SI U defined between an eNB and an SGW, the control plane interface SIC defined between eNB and an MME (also known as S1 -ME), and the S5 / S8 interface defined between an SGW and a PGW, note that the combination of S1 U and S1 C is often simplified to "S1".

MME 126 is a control node for the LTE access network. The MME 126 is responsible for tracking and searching procedures (JE 108 including retransmissions) The MME 126 handles the carrier activation / deactivation procedure and is also responsible for choosing the SGW for an UE 108 at the initial fix and at the time of an intra-LTE handover The MME 126 also authenticates the user by interacting with the HSS 124. The MME 126 also generates and distributes temporary identities to UE and terminates Signaling of No Access Strata (ÑAS). The MME 126 reviews the UE authorization 108 for camping on the Public Land Mobile Network (PLMN) of the service provider and imposes EU roaming restrictions The MME 126 is the network termination point for encryption / integrity protection for ÑAS signaling and controls key handling The legal interception of signaling is also supported by the MME 126. The MME also provides the control plane function, for mobility between LTE and network is 2G / 3G access with the interface S3 ending in the MME 126 of the SGSN 130. The MME 126 also terminates the interface S6a to the start HSS 126 for roaming UEs.

The SGW routes and sends user data packets, while also acting as the mobility anchor for the user plane during inter-eNB handovers and as the anchor for mobility between LTE and other 3GPP technologies (terminating S4 interface and transferring traffic between 2G / 3G and PDN GW systems). For idle state UE, the SGW terminates the downlink data path and active search when the downlink data arrives for the UE 108. The SGW handles and stores UE contexts, for example, parameters of the IP bearer service and IP address information. internal network routing. The SGW also replicates user traffic in case of legal intersection. The PGW provides connectivity to the UE 108 to external packet data networks as it is the point of departure and entry of traffic for the UE 108. An UE 108 may have simultaneous connectivity with more than one PGW to access multiple packet data networks. The P-GW performs policy enforcement, packet filtering for each user, load support, legal interception, and packet filtering. The PGW also provides an anchor for mobility between 3GPP and non-3GPP technologies such as WiMAX and 3GPP2 (CDMA IX and EvDO). The SGW or the PGW depending on the modality, can be used to provide deep packet inspection and provide publicity to the user on a per-subscriber basis as described above in a chassis that implements an SGW or a PGW.

The cellular core system 104 typically includes several switching elements, accesses and service control functions to provide cellular services. The cellular core system 104 often provides these services through a number of cellular access networks (e.g., RAN) and also interconnects the cellular system with other communication systems such as EPC 1 16. According to cellular standards , the cellular core system 104 may include a circuit switched (or voice-switched) portion for processing voice calls and switched packet portion (or data switching) to support data transfers such as, for example, mail messages electronic and web browsing. The circuit switched portion includes MSC / VLR 122 which switches or connects telephone calls between the cellular access system 106 and PSTN 104 or another network, between cellular core networks or others. The MSC / VLR 122 can support only an individual media stream (eg, individual TDM channel for the Standard interface, while the RTP stream for Aol P) to the RAN 1 10. This individual media stream can be used for supplementary services that involve multiple calls to / from the mobile such as call waiting. In other words, multiple calls to / from a GSM mobile share an individual media connection at the MSC access interface.

The cellular core system 104a may also include the HLR 120 to maintain "permanent" subscriber data and a VLR (and / or an SGSN) to maintain "temporary" subscriber data retrieved from HLR 120 and updated information on the location of those UE 108 using a wireless communications method. In addition, the cellular core system 104 may include Authentication, Authorization, and Accounting (AAA) which performs the role of authenticating, authorizing, and accounting for UE 108 operable to access the cellular core system 104. While the description of the core system 104 is described with respect to GSM networks, the core system 104 may include other cellular radio technologies such as UMTS, CDMA, and others without departing from the scope of this disclosure.

RAN 1 10 provides a radio interface between the mobile device 102a and the cellular core system 104a that provide real-time voice, data, and multimedia services (eg, a call) to the UE 108. In general, RAN 1 10 communicates Air boxes through radio frequency (RF) links. In particular, RAN 1 10 converts between air frames to messages based on physical link for transmission through the cellular core system 104a. RAN 1 10 can implement, for example, one of the following wireless interface standards during transmission: GSM access, UMTS access, Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Radio Service General Package (GPRS), Enhanced Data Rates for Global Evolution (EDGE), or proprietary radio interfaces. Users can subscribe to RAN 1 10, for example, to receive cellular telephone service, Global Positioning System service (GPS), XM radio service, etc.

RAN 1 10 may include Base Stations (BS) connected to Base Station Controllers (BSC) 132. BS receives and transmits air boxes between a geographic region of RAN 1 10 (ie, transmitted by UE 108) and communicates with the UE connected to the cellular core system 104. Each BSC 132 is associated with one or more BS 1 14 and controls the associated BS 1 14. For example, BSC 132 can provide functions such as handover, cellular configuration data, RF energy or any other suitable functions for handling radio resources and routing signals to and from BS, MSC / VLR 122 can be connected to BSC 132 through a standard interface such as the A interface. While the RAN elements 1 10 are described with respect to GSM networks, RAN 1 10 may include other cellular technologies such as UMTS, CDMA, and / or others. In the case of UMTS, RAN 1 10 may include Node B and Radio Network Controllers (RNC).

Turning to a more detailed description of the elements, the UE 108 comprises an electronic device operable to receive and transmit wireless communication with the system 100. As used in this description, the UE 108 is intended to encompass cellular telephones, data telephones, search engines, laptops, SIP phones, smart phones, personal data assistants (PDA), one or more processors with these or other devices, or any other suitable processing device capable of communicating information using radio technology. In the illustrated implementation, the UE 108 is capable of transmitting in one or more cellular bands. In these cases, the messages transmitted and / or received by the UE 108 can be based on a cellular radio technology. There can be any number of UE 108 communicatively coupled to cellular access network 1 10. Generally, UE 108 can transmit voice, video, multimedia, text, web content or any other user / client specific content. In summary, the UE 108 generates requests, replies or otherwise communicates with the mobile core system 104a through RAN 1 10 or EPC 1 16 through the E-UTRAN 1 14.

In some aspects of operation, the system 100 may execute one or more of the following: receive a Request to Provide Roaming Number (PRN) from a Home Location Register (HLR) in the CS network for a Station Roaming Number Mobile (MSRN) in connection with mobile termination call request; transmit a request to the UE through the Mobility Management Entity (MME) in the LTE system to interrupt the service to the CS system; receive a Request to Cancel Location (CL) of the HLR in connection with the location of the UE that is reassigned to a different MSC; in response to at least the CL request, transmit a request to Clear Routing Information (SRI) to the HLR; receive the MSRN from the MSC through the HLR; using the received MSRN, transmitting a PRN Acknowledge (PRN Ack) to the HLR so that the call ends with the UE using the MSRN; and / or others.

Figures 2A-2I are systems 200-280 illustrating signaling for executing CSFB according to some implementations of the present disclosure. Referring to Figure 2A, the GMSC 1 18 receives the signal 202 indicating a request to end a voice call with the (JE 108. Referring to Figure 2B, the system 210 illustrates the signal 212 that the MSRN requests for (JE 108. In particular, GMSC 1 18 transmits a request for Roaming Provide Number (PRN) to HLR 120, and HLR 120 transmits the PRN request to CSFB IWF 102 as MSC / VLR for UE 108. Referring to Figure 2C, the system 220 illustrates a signal 222 that illustrates a page requesting the UE 108 to update its location with HLR 120. In particular, the CSFB IWF 102 transmits the page to the MME 126, which, in turn, transmits the page to the UE 108 through the E-UTRAN 1 14. Referring to Figure 2D, the system 230 illustrates the UE 108 returning communication from the E-UTRAN 1 14 to the RAN 1 10. Referring to the Figure 2E, system 240 illustrates signal 242 requesting a location update of the cellular core network 1 12. In particular, the UE 108 transmits an update request to the HLR 120 through the BSC 132 and the MSC / VLR 122. Referring to Figure 2F, the system 250 illustrates a signal 252 that indicates that UE 108 is registered with a different MSC. In particular, the HLR 120 updates the registration of the UE 108 with the MSC / VLR 122 and transmits a request for Cancel Location (CL) to the CSFB IWF 102. Referring to Figure 2G, the system 260 illustrates the signal 262 requesting the current MSRN of the HLR 20. In particular, the CSFB IWF 102 transmits an SRI request to the HLR 120 using the MSISDN identified in the PRN request previously received by the GMSC 1 18 through the HLR 120. Referring to Figure 2H, system 270 illustrates signal 272 to recover MSRN and transmit MSRN to CSFB IWF 102. In particular, HLR 120 identifies MSC / VLR 122 as VMSC and retrieves the current MSRN of MSC / VLR 122. Referring to Figure 2I, system 280 illustrates a signal 282 that transmits the current MSRN to GMSC 1 18 through HLR 120 to complete the mobile termination network through UE 108.

Figures 3A-1, 3A-2 and 3B-1, 3B-2 illustrate a call flow 300 for executing a CSFB according to some implementations of the present disclosure. In the call flow 300, the UE 108 initiates the Location Area Update procedure or the Combined RA / LA Update if the LA of the cellular node is different from that stored in the UE 108. The IWF CSFBs are assigned with a LAI that is mutually exclusive of those used in 2G / 3G space that the UE 108 imposes to always initiate a Location Area Update. In the idle mode, the MME 126 sends search request to the eNodeB 114 which in turn sends the request to the UE 108. The MME 126 sends the Service Request to the CSFB IWF 102 after receiving the Extended Service Request from the UE 108. In active mode, the MME 126 sends the CS Search request directly to the UE 108 since it has a S 1 connection established. The MME 126 sends the Service Request to the CSFB IWF 102 immediately after sending the Search Request to the UE 108. In some implementations, the CSFB IWF 102 may set the Service Indicator to "CS Call Indicator" in the message of Search Request of SGAP. The IWF 102 CSFB may identify this upon receipt of the MAP PRN message from HLR 120. The IWF 102 CSFB may not include the following attributes in the SGAP search request since they may not be available (eg, LCS client identity, LCS indicator). The MSC / VLR 122 may not receive a service request message from the CSFB IWF 102. 3GPP TS 23.272 says that the Service request message may be used with an activator to inform the calling party that the call is progressing and to initiate the CFNRy chronometer. The CSFB IWF 102 can follow standard procedures to inform call progress. The calling process can be activated by normal procedures once the UE interrupts GERAN / U-TRAN service and the call is configured there. Once the CSFB IWF 102 has received an SGsAP service request from the MME 122, it can send retries of subsequent pages. The 2G / 3G BSC / MSC may not receive a search response from the UE 108 because it always performs a location area update after moving from E-UTRAN 1 14. The HLR 120 sends the MAP canceling location to the old MSC ( CSFB IWF 102 in this case) in parallel with handling the MAP update location of the new MSC / VLR 122. The CSFB IWF 102 may not wait for the MAP update location procedures (which include one or more MAP insertion subscriber data messages) to complete before sending MAP canceling location. The MAP update location procedures of the new MSC / VLR to HLR 120 and the MAP SRI procedures of CSFB IWF 102 can happen in parallel or at least in connection. The CSFB IWF 102 may be unaware of when the new update location is completed and may not wait to send MAP SRI to the HLR 120. The trigger for CSFB IWF 102 to send the MAP SRI may be the MAP cancellation location reception . The HLR 120 may wait until the MAP update location of the new MSC / VLR 122 is completed before handling the MAP SRI message of the IWF 102 CSFB. Basically the IWF 102 CSFB may wait for the MAP update location procedures to be performed. complete before sending the MAP PRN message to the new MSC / VLR 122. The CSMT indicator may not be supported by the 2G / 3G MSC / VLR and therefore you can ignore the parameter if it is received from the UE 108 in the message of update location. Because of this, the MSC / VLR 122 can release the SCCP connection to the user after completion of the location area update procedures. The HLR may send both IMSI and MSISDN in MAP PRN message to CSFB IWF 102. The IWF 102 CSFB upon receiving an error response for MAP SRI Request may rely on the same PRN response to HLR 120 for the initial call. The CSFB IWF 102 may include the suppress T-CSI parameter in the MAP SRI request sent to HLR 120. The CSFB IWF 102 may substantially ignore all service indications of the HLR 120 in the MAP SRI response. If the inter-RAT transfer from E-UTRAN 1 14 to UMTS / GSM can be supported (ie, transfer from an active packet station), the MME 126 can interact directly with the SGSN as specified in 3GPP TS 23.401. The CSFB IWF 102 may be involved in these procedures. The CSFB architecture can introduce additional post-dialing delay compared to a standard CSFB call attempt by invoking a Location Area Update procedure each time the E-UTRAN subscriber 14 is moved to UTRAN / GERAN. The M T can be managed by the 2G / 3G MSC / VLR 122. In cases, the roaming retry procedures may not be required in this CSFB IWF architecture.

In some implementations, the MME 126 may send the SGsAP reject search message to the IWF 102 CSFB and the corresponding action in IWF CSFB. If the UE 108 is known and is considered as IMSI fixed to the EPS services and "SMS only", the MME 126 may return a reject SGsAP message indicating in the SGS cause of the information element "mobile terminating call of CS service interruption rejected by the user. " The CSFB IWF 102 can send MAP response to HLR 120 with User Error configuration for "installation not supported". If UE 108 is known and is marked as IMSI detached from CPS or IMSI services (implicitly or explicitly) separated from non-EPS services, that is, the status of the SGs association is the NULL SGs, the MME 126 may return a reject SGsAP search message that indicates The SGs cause of information element of the separation circumstance ("IMSI separated from CPS service", "IMSI separated from non-EPS services" or "IMSI implicitly separated from non-EPS services"). The CSFB IWF 102 can send the response from MAP PRN to HLR 120 with User Error setting to "Unidentified Subscriber." If UE 108 is unknown and "MME Reset" is set to "false" MME 126 may return an SGsAP search rejection message that indicates to the SGs the cause of the information element "Unknown IMSI." The CSFB IWF 102 can send the response from MAP PRN to HLR 120 with User Error configuration to "unknown subscriber." If the UE 108 is uncovered Since "MME reset" is set to "true" and is considered to be IMSI fixed EPS services and "SMS only", the MME 126 may return a reject SGsAP search message indicating that in SGs c cause of the element of information "mobile terminating CS service interruption call rejected by the user". The CSFB IWF 102 can send the response from MAP PRN to HLR 20 with User Error settings for "installation not supported". The MME 126 can return a message that can not be reached from SGsAP that indicates in the SGs cause of the information element "UE not reachable" if the UE 108 is marked as not reachable, as indicated by the Search Procedure Indicator set to "false." The IWF 102 CSFB upon receiving message not achievable from SGSAP of MME 126, the CSFB IWF 102 may send the MAP response message. PRN with User Error set to "no subscriber response." The IWF 102 CSFB may change to the appropriate SG status based on the cause of rejection in the Reject Search message if the UE 108 fails to find the GERAN radius / UTRAN with the CS service interruption attempt, the call attempt may fail.In this scenario, the HLR 120 may expire waiting for the PRN response from CSFB IWF 102.

Figure 4 is a flow chart 400 illustrating an illustrative method for executing a CSFB according to some implementations of the present disclosure.

Method 400 begins at step 402 where a PRN request is received from the HLR. For example, the CSFB IWF 102 in Figure 1 may receive a PRN request identifying an MSISDN of the UE 108 of the HLR 120. In step 404, the IMSI and the MSIDN identified in the PRN request are stored. In the example, the CSFB IWF 102 can store IMSI and the IMSIDN identified by the PRN request. Then, in step 406, the UE is searched through the MME in an LTE system to update the location through the CS network. As for example, the CSFB IWF 102 can transmit a page to the MME 126 for the UE 108. In connection with the location update, a request to cancel location (CL) is received from the HLR based on assigning a new MS to the UE in step 408. Again in the example, the HLR 120 can transmit CL request to the CSFB IWF 102 based on the HLR 120 which assigns the MSC / VLR 122 to the UE 108. In step 410, the stored MSISDN is recovered from memory. By switching to the example, the CSFB IWF 102 can retrieve the MSISDN from the memory that was identified in the PRN request. Then, in step 412, a MAP SRI request is transmitted to the HLR including the previously received MSISDN. In the example, the CSFB IWF 102 transmits, to the HLR 120, a MAP SRI request that includes the MSISDN identified in the PRN request. A MAP SRI Recognition identifying the current MSRN of the UE is received in step 414. Then, in step 416, a Recognition of P RN identifying the current MSRN is transmitted to the HLR. Even again returning to the example, the CSFB IWF 102 can transmit a PRN Recognition that includes the current MSRN from UE 108 to HLR 120 to terminate the call with UE 108.

Figure 5 is a call flow diagram illustrating a modality of a new mobile initiated by network terminating USSD request / notification procedure. USSD is a protocol used by GSM cell phones to communicate with the service provider's USSD server. In this scenario, the MSC / VLR that is executing the service interruption is different from that when the UE first interrupts the service to the CS. In other words, the MSC changes with interruption of service during the application / notification procedure of MT USSD (Unstructured Supplemental Service Data). The IWF initiates the service interruption as in the case of an MT call and then acts as the USSD server and delivers the USSD request / notification to the UE through the HLR and the new MSC. The call flow shown in Figure 5 is also applicable to MT USSD notification initiated by network as well.

Focusing on the call flow portion within the box, the IWF acts as the USSD server and sends a MAP USSD request (Part of Mobile Applications) to the HLR. In response, the HLR sends the USSD request to the new MSC / VLR. The new MSC / VLR directs the USSD request to the UE by standard CS procedures and sends the received response from the UE to the HLR. A USSD Acknowledgment is sent to the HLR by the MSC / VLR in response to receiving the UE response. The HLR delays the response to the IWF, which also transfers the USSD response to the HLR. The HLR then sends a USSD response to the USSD server or USSD application as the case may be.

Figure 6 is a simplified block diagram of an illustrative embodiment of a communication system for a new mobile termination location reporting (MT-LR) process shown in Figure 7 and described below. Figure 6 is similar to Figure 1 described in detail above. As further shown in Figure 6, GMLC 1 19 is in communication with the IWF 1 02 through a specified MAP-based LG interface by 3GPP.

Figure 7 is a call flow diagram illustrating a modality of a new mobile termination location reporting procedure (MT-LR). As before, in this scenario the MSC / VLR that is executing the service interruption is different from that when the UE first interrupts the service to CS. In other words, the MSC changes with service interruption during the MT-LR procedure. The IWF initiates the service interruption to CS as in the case of an MT call. Once the service interruption is complete, the IWF acts as GMLC and routes the location query to the new MSC upon obtaining the new MSC address from the HLR.

Focusing on the call flow portion within the box, the IWF sends a MAP SRI-LCS request (Shipping Location Information Services) to the HLR. The request can identify the subscriber using IMSI (International Mobile Subscriber Identity) or MSISDN (International Mobile Station Subscriber Directory Number A) depending on which is received in the MAP Provision Subscriber Location (PSL) application from the GMLC (Mobile Access Location Center). In response, the HLR sends a response including the network node number (identifying the new MSC) to the IWF. The IWF transfers the MAP PSL received from GMLC to the NW node number returned by the HLR. The UE location procedure as specified in 3GPP TS 23.271 is carried out. The MSC / VLR returns an answer from MAP PSL to the IWF. The IWF then transfers the PSL response to the GMLC.

Figure 8 is a call flow diagram illustrating a modality of new provision subscriber information, service interruption to the CS procedure. MAP Provision Subscriber Information (PSI) is a procedure commonly used in the CS network where the VLR is consulted to provide subscriber location. As before, in this scenario the MSC / VLR that is executing the service interruption is different from that when the JE first interrupts the CS.

Focusing on the call flow portion within the box, the IWF initiates the CS service interruption as in the case of an MT call and then upon receiving Cancel HLR Location, assumes the role of gsmSCF (Service Control Function GSM) and sends a MAP Interrogation Message Anytime (ATI) to the HLR requesting the same group of information that was mentioned in the MAP PSI request message. The information within the response of the MAP Anytime Moment message is then copied into the MAP PSI request message response and sent to the HLR completing the procedure.

The features of the present invention that are believed to be novel are set forth below with particularity in the appended claims. However, modifications, variations, and changes to the illustrative embodiments described above will be apparent to those skilled in the art, and the drainage assembly described herein covers such modifications, variations, and changes if they are not limited to the specific validities described herein.

Claims (3)

1. - A method that includes: receiving, at an IWF network node (Internet Work Function), an Unstructured Service Data Message from Mobility Application Part (MAP USSD) identifying a User Equipment (UE) originating from an application of USSD, the UE associated with a first Mobile Switching Center (MS); initiate Interrupt Switch Circuit Service (CSFB) when sending a search request to the UE; receiving a Cancel Location message associated with the UE from a Home Location Register (HLR) indicative of the UE that is associated with a second MSC; send the MAP USSD message to the UE through the HLR and the second MSC; receive a MAP USSD response message from the UE through the HLR; Y send the MAP USSD response message to the USSD application.

2. - A method that includes: receiving, at an IWF network node (Internet Work Function), a message from Routing Information Location Services Mobility Application Submission (SRI-LCS) that identifies a User Equipment (UE) originated from a Center Mobile Access Location (GMLC), the UE associated with a first Mobile Switching Center (MSC); initiate interruption of C-switched service (CSFB) when sending a search request to the UE; receiving a Cancel Location message associated with the UE from a Home Location Register (HLR) indicative of the UE that is associated with the second MSC; send the SRI-LCS message to the UE through the HLR and the second MSC; receive an SRI-LCS response message from the HLR; send a MAP Provision Subscriber Location (PSL) message to the second MSC; receive a MAP PSL response message from the second MSC; Y send the MAP PSL response message to the GMLC.

3. - A method that includes: receiving, at an IWF network node (Internet Work Function), a Mobility Application Part Provision Subscriber Information (MAP PSI) message identifying a User Equipment (UE) originating from a Register of Start Location (HLR), the UE associated with a first Mobile Switching Center (MSC); initiate Interruption of Switched Circuit Service (CSFB) when sending a search request to the UE; receive a Cancel Location message associated with the UE of the HLR indicative of the UE that is associated with a second MSC; send a Message of Any MAP Question (API) to the UE through the HLR and the second MSC; receive a response message from the MAP API of the HLR; and send MAP API response information in a MAP PSI response message to the HLR.