Patent Description:
Presently, wireless communication devices, such as user equipment (UE), communicate with other communication devices using wireless signals. In 3rd Generation Partnership Project (3GPP) a study item in document <NPL>" was agreed. This study aims to fulfil the 3GPP SA1 requirements to provide UEs with network access to restricted local operator services even if they are not successfully authenticated. The ability to provide access to such local services has been available to U. operators, but only on a proprietary basis.

PARLOS is also mentioned in <NPL>, where reference is made to a new WID, SP-<NUM>. No implementation details are provided concerning UE attachment and registration for restricted local operator services.

Paper <NPL>, discusses an update to an SA5 review (given in S3-<NUM>) of solution #<NUM>: IMS emergency session with or without IMS registration failure.

<CIT> describes a method for restoring connectivity between a node in an IP Multimedia Subsystem network, and a User Equipment. The UE is associated with a Proxy Call Session Control Function node, P-CSCF, of the IMS network, and with at least one control node of a packet access network, through which the UE connects to the IMS network. The method allows for restoring the connectivity of the UE to an IMS network node after the IMS node has failed to establish a communication to the UE via the P-CSCF node.

In order to describe the manner in which advantages and features of the disclosure can be obtained, a description of the disclosure is rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. These drawings depict only example embodiments of the disclosure and are not therefore to be considered to be limiting of its scope. The drawings may have been simplified for clarity and are not necessarily drawn to scale.

Embodiments provide a method and apparatus for signaling of system information. According to a possible embodiment, a session initiation protocol register request message can be received from an apparatus. The session initiation protocol register request message can include an indication for restricted local operator services. A detection can be made that the session initiation protocol register request message is for restricted local operator services service based on the restricted local operator services indication. The session initiation protocol register request message can be forwarded to a serving call session control function in response to the detecting that the session initiation protocol register request message is for restricted local operator services service. A response message indicating the apparatus is registered with restricted local operator services of an internet protocol multimedia core network subsystem can be sent to the apparatus.

According to another possible embodiment, an Attach procedure for restricted local operator services for a user equipment can be performed. A proxy call session control function address for restricted local operator services can be received during the Attach procedure. Session initiation protocol register request message, the session initiation protocol register request message including an indication for restricted local operator services and the session initiation protocol register request message includes an internet protocol multimedia public user identification can be generated based on an identification of the apparatus. The session initiation protocol register request message to can be sent the proxy call session control function address. The session initiation protocol register request message can include the indication for restricted local operator services. A response message indicating the apparatus is registered with restricted local operator services of an internet protocol multimedia core network subsystem can be received.

<FIG> is an example block diagram of a system <NUM>, according to a possible embodiment. The system <NUM> can include a UE <NUM>, at least one network entity <NUM>, such as a base station, a network <NUM>, and an Internet Protocol (IP) Multimedia Core Network Subsystem (IMS) <NUM>. The UE <NUM> can be a wireless wide area network device, a user device, wireless terminal, a portable wireless communication device, a smartphone, a cellular telephone, a flip phone, a personal digital assistant, a personal computer, a selective call receiver, an Internet of Things (IoT) device, a tablet computer, a laptop computer, or any other user device that is capable of sending and receiving communication signals on a wireless network. The network entity <NUM> can be a wireless wide area network base station, can be a NodeB, can be an enhanced NodeB (eNB), can be a New Radio NodeB (gNB), such as a <NUM> NodeB, can be an unlicensed network base station, can be an access point, can be a base station controller, can be a network controller, can be a Transmission/Reception Point (TRP), and/or can be any other network entity that can provide wireless access between a UE and the network <NUM>.

The network <NUM> can include any type of network that is capable of sending and receiving wireless communication signals. For example, the network <NUM> can include a wireless communication network, a cellular telephone network, a Time Division Multiple Access (TDMA)-based network, a Code Division Multiple Access (CDMA)-based network, an Orthogonal Frequency Division Multiple Access (OFDMA)-based network, a Long Term Evolution (LTE) network, a 3rd Generation Partnership Project (3GPP)-based network, a satellite communications network, a high altitude platform network, the Internet, and/or other communications networks.

In operation, the UE <NUM> can communicate with the network <NUM> via the network entity <NUM>. For example, the UE <NUM> can send and receive control signals described herein on a control channel and user data signals described herein on a data channel via a message(s) communicated between the UE <NUM> and the network entity <NUM>. The network <NUM> can include various NEs, such as a Mobility Management Entity (MME) <NUM>, a Policy and Charging Rules Function (PCRF) <NUM>, a Packet Data Network Gateway (PGW) <NUM>, a Temporary Subscriber Server (TSS) <NUM>, and a Home Subscriber Server (HSS) <NUM>. The network <NUM> can communicate with the IMS <NUM>. The IMS <NUM> can include various elements, such as the P-CSCF <NUM>, a Serving Call Session Control Function (S-CSCF) <NUM>, at least one Application Server (AS) <NUM>, and an Interrogating Call Session Control Function (I-CSCF) <NUM>.

In the following embodiments, the term eNB/ gNB can be used for a base station but the base station can be replaced by any other radio access node (RAN), such as an Access Point (AP), a New Radio (NR) node, etc. Further, the proposed system <NUM> and methods described below can be applied to other types of networks including IEEE <NUM> variants, Global System for Mobile communication (GSM), General Packet Radio Services (GPRS), Universal Mobile Telecommunications Service (UMTS), LTE variants, Code Division Multiple Access (CDMA)<NUM>, Bluetooth, ZigBee, Sigfoxx, etc. The described embodiments can also be applicable to Next Generation Mobile Networks, see 3GPP TS <NUM> and 3GPP TS <NUM>, where for example the MME <NUM> can map to Access and Mobility Management Function (AMF), and can partially map to AMF for terminating Non Access Stratum (NAS) Sparse Mode (SM) protocol, Session Management Function (SMF)/User Plane Function (UPF) can map to a Serving Gateway (SGW) <NUM>/PGW <NUM>, and a Home Subscriber Server (HSS) <NUM> can map to a Unified Data Management (UDM)/User Data Repository (UDR). The new logical functional entity TSS <NUM> may be standalone or can be collocated with the MME <NUM>, a Home Subscriber Server (HSS) or an Authentication, Authorization, and Accounting (AAA) server, or even the AMF, SMF, UDM, UDR, or any other involved node in the network <NUM>. In the following embodiments, the UE <NUM> can refer to a mobile device, but it can also be a Mobile Station (MS) without a Universal Mobile Telecommunications SIM (USIM) or USIM/Subscriber Identify Module (SIM) or a Mobile Equipment (ME). The UE <NUM>, MS, or ME, can be assumed to be preconfigured with a public and private key pair or can be capable of generating them based on an internal logic, when required. The system <NUM> can allow an unauthenticated UE <NUM> to access restricted local operator services based on operator policy and regional regulatory requirements. The system <NUM> can identify an origination to restricted local operator services, such as dialed digits and captive portal. The system <NUM> can determine that the RLOS is available. The system <NUM> can allow access to restricted operator services by the unauthenticated UE <NUM>. The system <NUM> can charge for information collection. The system <NUM> can account for security considerations. The wide deployment of LTE and corresponding introduction of Voice Over LTE (VoLTE) can use a standardized mechanism to allow the UE <NUM> to access these services, such as dialing a particular digit string and accessing a captive portal, without necessarily being successfully authenticated for access. The embodiments disclosed herein can fulfill the 3GPP requirements for security during the UE <NUM> accessing the network <NUM> to the RLOS even if the UE <NUM> is not successfully authenticated.

The system <NUM> provides a solution where the UE <NUM> is also dialing a short code number and gets connected to an audio service/help desk/application server. Since this is limited to LTE and VoLTE, it is assumed that the IMS <NUM> can be used for delivering the voice session. This is difficult since the IMS <NUM> is designed for authenticated services of the network operator and executes those services in the home network, such as the S-CSCF <NUM> that can be located in a Home Public Land Mobile Network (HPLMN). The system <NUM> can account for a completely new connection of a delivery session for the IMS <NUM>.

The IMS <NUM> can conform with several 3GPP releases in Technical Specification (TS) <NUM> and with several other additional services or interactions with the network <NUM> which can conform to Technical Specification (TS) <NUM>. Current IMS platforms do not allow an unregistered user to access the operator's IMS services. There are some exceptions to such restrictions, such as for an emergency call or mobile termination session delivery to unregistered users, but not for a mobile origination case. In case of a Subscriber Identify Module (SIM)-less emergency call and Universal Mobile Telecommunications SIM (USIM)-less emergency call there is no encryption setup on the data bearer and no IMS encryption in place. PARLOS encryption on the IMS layer can be beneficial in order to protect the data associated with the UE <NUM>.

The system <NUM> can provide IMS service to the unauthenticated UE <NUM>, such as when the UE <NUM> can be authenticated via a subscription repository like Home Subscriber Server (HSS) and can provide security in protocol layers of the IMS. The UE <NUM> can perform an Attach procedure for RLOS before an event, such as when the UE <NUM> is RLOS attached and has IP connectivity to a RLOS service. During the Attach procedure the UE <NUM> can receive an address of the P-CSCF <NUM> for RLOS. If the MME <NUM> provisions the TSS <NUM> with specific information for the UE <NUM>, then the MME <NUM> can configure the TSS <NUM> with information the TSS <NUM> exchanged or assigned to the UE <NUM> during the Attach procedure. This information may contain some security context which can be reused in the following embodiments for securing Session Initiation Protocol (SIP) signaling. The PARLOS can be specified for Evolved Universal Terrestrial Radio Access (E-UTRA)/LTE, or any future access technology, such as New Radio. The embodiments can assume that the UE <NUM> is not performing cell reselection to another Radio Access Technology (RAT) of the PARLOS PLMN, such as <NUM>nd Generation <NUM> or <NUM> wireless, and cannot signal Single Radio Voice Call Continuity (SRVCC) capabilities to the network entity <NUM>. If the network <NUM> assigns any Quality of Service (QoS) Class Identifier (QCI), such as QCI=<NUM> or QCI=<NUM>, bearers to the RLOS IMS media bearers, the network <NUM> can assure that the UE <NUM> is not triggering SRVCC by accidently sending its SRVCC capabilities to the network entity <NUM>.

An embodiment can include IMS registration for RLOS and an IMS session setup procedure for RLOS. <FIG> is an example signal flow diagram <NUM> of the example system of <FIG>. The signal flow diagram <NUM> can make the assumptions mentioned above as prerequisite, that is at <NUM> that the UE <NUM> can be RLOS network attached. The P-CSCF <NUM> may be dedicated for RLOS and may be selected by the PGW <NUM> based on an indication from the MME <NUM> or a rule from the PCRF <NUM> and provided to the UE <NUM> during the Attach procedure.

At <NUM> and <NUM>, the UE <NUM> can send a SIP REGISTER request message towards the P-CSCF <NUM>. The PGW <NUM> can perform gating and authorization of a destination address for the P-CSCF <NUM>. An IP Multimedia Public User Identification (IMPU) for the UE <NUM> can be used in the SIP REGISTER request message that includes an identification of the UE <NUM> generated or received during the Attach procedure, and, if not suitable for the IMS <NUM>, can be combined with the network domain derived from the address of the P-CSCF <NUM> for RLOS, received during the Attach procedure. The UE <NUM> may include its Public Key as well in the SIP REGISTER request message to the P-CSCF <NUM>, but it can be further assumed that security context of the UE <NUM> is stored in the TSS <NUM> already.

At <NUM>, the PGW <NUM> can forward the SIP REGISTER request message to the P-CSCF <NUM>, which may be dedicated for RLOS. The P-CSCF <NUM> can forward the SIP REGISTER request message to the S-CSCF <NUM>, which may be dedicated for RLOS as well. The P-CSCF <NUM>, the I-CSCF <NUM>, and the S-CSCF <NUM> may be collocated for RLOS.

At <NUM>, the S-CSCF <NUM> can detects an RLOS registration procedure and can withhold contacting the HSS <NUM> of the PLMN, instead the S-CSCF <NUM> queries the TSS <NUM> with the identification of the UE <NUM> that can be provided in the SIP REGISTER request message. This identification of the UE <NUM> may be configured by the MME <NUM> during Attach procedure.

At <NUM>, the TSS <NUM> can provide a RLOS subscriber profile to the S-CSCF <NUM> including the initial Filter Criteria(s) (iFC(s)) on which the AS(s)) can be triggered. The TSS <NUM> may send a validity time for which the UE <NUM> can be eligible to keep an IMS registration. The validity time could be interpreted in several ways, it could be a maximum time registration with the IMS <NUM> can be valid and can be renewed, or it could describe an exact time when no more registration is possible at all, such as ongoing registration with the IMS <NUM> that can be terminated at this time and further attempts can be rejected if IP connectivity is still available to reach the P-CSCF <NUM>. A Subscription profile from the TSS <NUM> may contain security information which can be used to start ciphering of signaling with the IMS <NUM>.

At <NUM>, the S-CSCF <NUM> can perform service control and can include the relevant AS(s) from the iFC(s) in the path. Depending on the availability of the validity time and its usage, the S-CSCF <NUM> or at least one AS <NUM> can adjust the timer for the registration to the validity time received from the TSS <NUM>, or a trigger when to initiate de-registration with the IMS <NUM>.

At <NUM>, the S-CSCF <NUM> provides the key, such as a Public Key, for the UE <NUM> from the security information to the P-CSCF <NUM> in a <NUM> OK response. In a scenario in which the TSS <NUM> can store a symmetric key which can be exchanged during the Attach procedure, then the key can be withheld from being sent to the UE <NUM> at <NUM>. A generated input parameter for the symmetric encryption may be sent to the UE <NUM> instead.

At <NUM>, the P-CSCF <NUM> can start ciphering with a key, such as a Public Key for the UE <NUM> and can provide a key, such as a Public key for the P-CSCF <NUM> to the UE <NUM> in the <NUM> OK response. In a scenario in which a symmetric key can be received from the TSS <NUM>, then a security key, such as a Public Key, for the P-CSCF <NUM> is withheld from being provided. At <NUM>, the UE <NUM> can now be registered with the IMS <NUM> for RLOS with SIP encryption enabled.

In another embodiment, the TSS <NUM> can be withheld from being used for querying the security information and the service profile. <FIG> is another example signal flow diagram <NUM> of the example system of <FIG>. The signal flow diagram <NUM> can make the assumptions mentioned above as prerequisite, that is at <NUM> that the UE <NUM> can be RLOS network attached. The P-CSCF <NUM> may be dedicated for RLOS and may be selected by the PGW <NUM> based on an indication from the MME <NUM> or a rule from the PCRF <NUM> and provided to the UE <NUM> during the Attach procedure. At <NUM> and <NUM>, the UE <NUM> can send a SIP REGISTER request message towards the P-CSCF <NUM>. The PGW <NUM> can perform gating and authorization of the destination address for the P-CSCF <NUM>. The IMPU for the UE <NUM> can be used in the SIP REGISTER request message includes an ID of the UE <NUM> that can be generated or received during the Attach procedure, and, if not suitable for IMS, can be combined with the network domain derived from the address of the P-CSCF <NUM> for RLOS, received during the Attach procedure. The UE <NUM> may include its Public Key as well in the SIP REGISTER request message to the P-CSCF <NUM> as well as security capabilities for the UE <NUM>.

At <NUM>, the PGW <NUM> can forward the SIP REGISTER request message to the P-CSCF <NUM>, which may be dedicated for RLOS. The P-CSCF <NUM> stores a Public Key for the UE <NUM> and the security capabilities, if available.

At <NUM>, the P-CSCF <NUM> can forward the SIP REGISTER request message to the S-CSCF <NUM>, which may be dedicated for RLOS as well. The P-CSCF <NUM>, the I-CSCF <NUM>, and the S-CSCF <NUM> may be collocated for RLOS.

At <NUM>, the S-CSCF <NUM> can detect an RLOS registration procedure and can withhold contacting the HSS <NUM> of the PLMN. The S-CSCF <NUM> may have a preconfigured RLOS subscriber profile including the iFC(s) on which the AS <NUM> to be triggered. The S-CSCF <NUM> can perform service control and can include relevant AS(s) <NUM> from the iFC(s) in the path. The AS <NUM> may have information about a validity time for which the UE <NUM> is eligible to keep an IMS registration. The validity time could be interpreted in several ways. For example, the validity time could be a maximum time the IMS registration as such is valid and can be renewed or could describe an exact time when no more registration is possible, such as when ongoing registration with the IMS <NUM> that can be terminated at this time and further attempts can be rejected if IP connectivity is still available to reach the P-CSCF <NUM>.

At <NUM>, the S-CSCF <NUM> can send a SIP <NUM> OK response to the P-CSCF <NUM> and the UE <NUM> is now registered for RLOS with the IMS <NUM>. At <NUM>, the P-CSCF <NUM> may select a Public Key for the P-CSCF <NUM> or may generate a symmetric key based on security capabilities of the UE <NUM>. At <NUM>, the P-CSCF can start ciphering with a security key, such as a Public Key, for the UE <NUM> and can provide a security key, such as a Public Key, for the P-CSCF <NUM> to the UE <NUM> in the <NUM> OK response. In a scenario in which a symmetric key is generated, the UE <NUM> can use the symmetric key for encryption of further SIP signaling, otherwise the UE <NUM> can use the Public Key for the P-CSCF <NUM> for encryption. At <NUM>, the UE <NUM> can now be registered with the IMS <NUM> for RLOS with SIP encryption enabled.

In another embodiment, only the Public Key of the P-CSCF <NUM> can be returned to the UE <NUM> in the <NUM> OK response at <NUM>. The UE <NUM> or the IMS <NUM> could then initiate a SIP request to trigger generation of a symmetric key, which can replace <NUM>, in the other entity which can get provisioned in the acknowledgement, or as another variant can provide a symmetric key to the other entity which then can get acknowledged. The SIP message of the request could be of any format, such as INVITE, OPTIONS, NOTIFY, SUBSCRIBE, MESSAGE, OK etc., and could be combined with a subsequent request of either the UE <NUM> or the IMS <NUM>.

<FIG> is an example signal flow diagram <NUM> for session setup for RLOS, according to a possible embodiment. The signal flow diagram <NUM> can make the assumptions mentioned above as prerequisite, that is at <NUM> that the UE <NUM> can be RLOS network attached. The P-CSCF <NUM> may be dedicated for RLOS and may be selected by the PGW <NUM> based on an indication from the MME <NUM> or a rule from the PCRF <NUM> and provided to the UE <NUM> during the Attach procedure. At <NUM> and <NUM>, the UE <NUM> can send a SIP INVITE request towards the P-CSCF <NUM>. The UE <NUM> may indicate RLOS, the ID of the UE <NUM> and the short code (local number, non-international format) in the SIP INVITE request, such as a Uniform Resource Identifier (URI). The message may be encrypted with a Public Key of the P-CSCF <NUM> or a symmetric key. The PGW <NUM> can perform gating and authorization of destination address of the P-CSCF <NUM>.

At <NUM>, the PGW <NUM> can forward the SIP INVITE request to the P-CSCF <NUM>, which may be dedicated for RLOS. At <NUM>, the P-CSCF <NUM> can decipher the message and checks the RLOS registration status for an ID of the UE <NUM>. At <NUM>, the P-CSCF <NUM> can forward the SIP INVITE request to the S-CSCF <NUM>, which may be dedicated for RLOS as well. The P-CSCF <NUM>, the I-CSCF <NUM> and the S-CSCF <NUM> may be collocated for RLOS. The S-CSCF <NUM> can detect a session setup request and can forward the session setup request to an appropriate AS <NUM>, configured with the iFC(s).

At <NUM>, the AS <NUM> can check whether the short code is allowed for RLOS and can replace the short code with a routable, such as an international format, request URI. The AS <NUM> can act as Back to Back User Agent (B2BUA). At <NUM>, the AS <NUM> can send the SIP INVITE request with the destination URI to the S-CSCF <NUM>. At <NUM>, the S-CSCF <NUM> can forward the SIP INVITE request to a remote end, such as another AS <NUM> or a remote UE <NUM>.

At <NUM>, the remote end can acknowledge the SIP INVITE request with a <NUM> OK response towards the S-CSCF <NUM>. At <NUM>, the S-CSCF <NUM> can forward the <NUM> OK response to the AS <NUM>. At <NUM>, the AS <NUM> can acknowledge the SIP INVITE request from the UE <NUM> and sends a <NUM> OK response to the P-CSCF <NUM>. At <NUM>, the P-CSCF <NUM> can encrypt the SIP INVITE request and can forward the <NUM> OK response to the UE <NUM>.

Thus in at least one embodiment that utilizes the TSS <NUM>, the UE <NUM> can compose its IMPU based on the ID of the UE <NUM> used in the Attach procedure, such as either an ID generated by the UE <NUM> or received during an Attach Accept message, and, if not already suitable for IMS, can be combined with the network domain derived from the address of the P-CSCF <NUM> for RLOS, received during the Attach procedure. The TSS <NUM> can store security context of the UE <NUM>, including a validity time, which indicates a final end of service provided by the IMS <NUM>. This information is generated/exchanged during the Attach procedure. Provisioning of the Public Key of the UE <NUM> and RLOS indication to the P-CSCF <NUM> can be in the SIP REGISTER request message. Such provisioning includes derivation of security material, such as Public Keys or symmetric keys, for encryption of SIP messages between UE <NUM> and P-CSCF <NUM>. RLOS Registration can be detected in the S-CSCF <NUM> based on RLOS indication in the SIP REGISTER request message, with a different procedure being performed for key exchange without use of the IMS <NUM>. The S-CSCF <NUM> can perform selection of the TSS <NUM> based on RLOS indication in the SIP REGISTER request message. The UE key, Public or symmetric key, can be provisioned from the TSS <NUM> to the P-CSCF <NUM> via the S-CSCF <NUM>. The P-CSCF Public Key or an input parameter for symmetric encryption can be provisioned to the UE <NUM> from the P-CSCF <NUM> in the SIP <NUM> OK response.

In at least one embodiment that does not rely on the TSS <NUM> includes key exchange between the UE <NUM> and the P-CSCF <NUM> with the possibility to create a symmetric key in the P-CSCF <NUM> for further SIP signaling encryption. The UE <NUM> can provide RLOS indication, such as a Public Key for the UE <NUM>, and security capabilities to the P-CSCF <NUM> in the SIP REGISTER request message. The S-CSCF <NUM> can be withheld from querying any database and can be preconfigured for RLOS with the service profile. The P-CSCF <NUM> can generate a symmetric key and/or can select a Public Key for the P-CSCF <NUM>. The P-CSCF <NUM> can provide the symmetric key or the Public Key of the P-CSCF <NUM> to the UE <NUM> in the <NUM> OK response of the registration.

It should be understood that, notwithstanding the particular procedures as shown in the figures, a variety of additional or different procedures can be performed depending upon the embodiment, and one or more of the particular procedures can be rearranged, repeated or eliminated entirely depending upon the embodiment. Also, some of the procedures performed can be repeated on an ongoing or continuous basis simultaneously while other procedures are performed. Furthermore, different procedures can be performed by different elements or in a single element of the disclosed embodiments.

<FIG> is an example flowchart <NUM> illustrating operation of an apparatus, such as the P-CSCF <NUM>, according to a possible embodiment. According to a possible embodiment, the flowchart <NUM> can be performed by the P-CSCF <NUM> and the referenced apparatus can be the UE <NUM>. At <NUM>, the SIP REGISTER request message from an apparatus can be received. The SIP REGISTER request message includes an indication for the RLOS. According to a possible embodiment, the SIP REGISTER request message can include security material, such as the Public Key associated with the apparatus. According to a possible embodiment, the SIP REGISTER request message can include the IMPU. According to a possible embodiment, the IMPU can include an ID associated with the apparatus and one of generated and received during an Attach procedure. According to a possible embodiment, if the IMPU is not suitable for the IMS <NUM> the IMPU can be combined with a network domain derived from an address associated with the P-CSCF <NUM> for the RLOS and received during the Attach procedure.

At <NUM>, the SIP REGISTER request message for the RLOS can be detected based on the RLOS indication. At <NUM>, a response message that the apparatus is registered with the RLOS of the IMS <NUM> can be sent.

According to a possible embodiment, the forwarding in <NUM> can further include the S-CSCF <NUM> can be selected based on the RLOS indication and can be in response to the detecting that the SIP REGISTER request message is for the RLOS. According to a possible embodiment, a Public Key can be generated, wherein the response message that the apparatus is registered with RLOS of the IMS <NUM> includes the generated Public Key. According to a possible embodiment, service control for the registration of the RLOS of the IMS <NUM> can be performed. The service control can include at least one of adjusting a timer for the RLOS registration to a validity time and triggering when to initiate de-registration of the IMS <NUM>. According to a possible embodiment, an IMS session can be established including the RLOS indication in a SIP INVITE request message.

According to a possible embodiment, a SIP INVITE request message can be sent to the network entity <NUM> based on an acceptance of the SIP REGISTER request message. According to a possible embodiment, the flowchart <NUM> can further include generating a Public Key for the apparatus and including the Public Key in the SIP REGISTER request message. According to a possible embodiment, the identification of the apparatus includes at least one of an identification of the equipment of the apparatus associated with an Attach procedure for the apparatus and the IMPU. According to a possible embodiment, a validity time is associated with the registered the RLOS of the IMS <NUM>.

<FIG> is an example flowchart <NUM> illustrating operation of an apparatus, such as the UE <NUM>, according to a possible embodiment. At <NUM>, the Attach procedure can be performed for the RLOS for the apparatus.

At <NUM>, the P-CSCF <NUM> address for the RLOS can be received during the Attach procedure. At <NUM>, a SIP REGISTER request message can be generated. The SIP REGISTER request message can include an indication for the RLOS and the SIP REGISTER request message can include the IMPU based on an identification of the UE <NUM>.

At <NUM>, the SIP REGISTER request message can be sent to the P-CSCF address, the SIP REGISTER request message including the indication for the RLOS. At <NUM>, a response message indicating the UE <NUM> is registered with the RLOS of the IMS <NUM> can be received.

According to a possible embodiment, a SIP INVITE request message can be sent to the network entity <NUM> based on an acceptance of the SIP REGISTER request message. According to a possible embodiment, the flowchart <NUM> can further include generating a Public Key for the apparatus and including the Public Key in the SIP REGISTER request message. According to a possible embodiment, for the flowchart <NUM> the identification of the apparatus can include at least one of an identification of the equipment of the apparatus associated with an Attach procedure for the apparatus and the IMPU. According to a possible embodiment, a validity time can be associated with the registered the RLOS of the IMS <NUM>.

<FIG> is an example block diagram of an apparatus <NUM>, such as the UE <NUM>, the network entity <NUM>, or any other wireless and non-wireless communication device disclosed herein, according to a possible embodiment. The apparatus <NUM> can include a housing <NUM>, a controller <NUM> coupled to the housing <NUM>, audio input and output circuitry <NUM> coupled to the controller <NUM>, a display <NUM> coupled to the controller <NUM>, a transceiver <NUM> coupled to the controller <NUM>, an antenna <NUM> coupled to the transceiver <NUM>, a user interface <NUM> coupled to the controller <NUM>, a memory <NUM> coupled to the controller <NUM>, and a network interface <NUM> coupled to the controller <NUM>. The apparatus <NUM> can perform the methods described in all the embodiments.

The display <NUM> can be a viewfinder, a liquid crystal display (LCD), a light emitting diode (LED) display, a plasma display, a projection display, a touch screen, or any other device that displays information. The transceiver <NUM> can include a transmitter and/or a receiver. The audio input and output circuitry <NUM> can include a microphone, a speaker, a transducer, or any other audio input and output circuitry. The user interface <NUM> can include a keypad, a keyboard, buttons, a touch pad, a joystick, a touch screen display, another additional display, or any other device useful for providing an interface between a user and an electronic device. The network interface <NUM> can be a Universal Serial Bus (USB) port, an Ethernet port, an infrared transmitter/receiver, an IEEE <NUM> port, a WLAN transceiver, or any other interface that can connect an apparatus to a network, device, or computer and that can transmit and receive data communication signals. The memory <NUM> can include a random-access memory, a read only memory, an optical memory, a solid-state memory, a flash memory, a removable memory, a hard drive, a cache, or any other memory that can be coupled to an apparatus.

The apparatus <NUM> or the controller <NUM> may implement any operating system, such as Microsoft Windows®, UNIX@, or LINUX®, Android™, or any other operating system. Apparatus operation software may be written in any programming language, such as C, C++, Java or Visual Basic, for example. Apparatus software may also run on an application framework, such as, for example, a Java® framework, a. NET® framework, or any other application framework. The software and/or the operating system may be stored in the memory <NUM> or elsewhere on the apparatus <NUM>. The apparatus <NUM> or the controller <NUM> may also use hardware to implement disclosed operations. For example, the controller <NUM> may be any programmable processor. Disclosed embodiments may also be implemented on a general-purpose or a special purpose computer, a programmed microprocessor or microprocessor, peripheral integrated circuit elements, an application-specific integrated circuit or other integrated circuits, hardware/electronic logic circuits, such as a discrete element circuit, a programmable logic device, such as a programmable logic array, field programmable gate-array, or the like. In general, the controller <NUM> may be any controller or processor device or devices capable of operating an apparatus and implementing the disclosed embodiments. Some or all of the additional elements of the apparatus <NUM> can also perform some or all of the operations of the disclosed embodiments.

In operation as the P-CSCF <NUM>, the transceiver <NUM> can receive the SIP REGISTER request message from an apparatus, such as the UE <NUM> wherein the SIP REGISTER request message comprises an indication for the RLOS. According to a possible embodiment, the SIP REGISTER request message can include security material, such as the Public Key associated with the apparatus. According to a possible embodiment, the SIP REGISTER request message includes the IMPU, the IMPU including an ID associated with the apparatus and one of generated and received during an Attach procedure, and, if the IMPU is not suitable for the IMS, the controller <NUM> can combine the IMPU with a network domain derived from an address associated with the P-CSCF <NUM> for RLOS and received during the Attach procedure.

The controller <NUM> can detect the SIP REGISTER request message for the RLOS based on the RLOS indication. The transceiver <NUM> can forward the SIP REGISTER request message to the S-CSCF <NUM> in response to the detecting that the SIP REGISTER request message is for RLOS. The transceiver <NUM> can send a response message indicating the apparatus is registered with RLOS of the IMS <NUM>.

According to a possible embodiment, the controller <NUM> can select the S-CSCF <NUM> based on the RLOS indication and in response to the detecting that the SIP REGISTER request message is for the RLOS. According to a possible embodiment, the controller <NUM> can generate a Public Key, wherein the response message that the apparatus, such as the apparatus, is registered with RLOS of the IMS <NUM> includes the generated Public Key. According to a possible embodiment, the controller <NUM> can perform service control for the registration of the RLOS of the IMS <NUM>, the service control comprising at least one of adjusting a timer for the RLOS registration to a validity time and triggering when to initiate de-registration of the IMS <NUM>. According to a possible embodiment, the transceiver <NUM> can establish an IMS session including the RLOS indication in a SIP INVITE request message.

In operation as the UE <NUM>, the transceiver <NUM> can perform the Attach procedure for the RLOS for the UE <NUM>. The transceiver <NUM> can receive the P-CSCF <NUM> address for RLOS during the Attach procedure. The controller <NUM> can generate an indication for RLOS and the SIP REGISTER request message includes the IMPU based on an identification of the UE <NUM>. The transceiver <NUM> can send the SIP REGISTER request message to the P-CSCF address, the SIP REGISTER request message can include the indication for RLOS. The transceiver <NUM> can receive a response message indicating the UE <NUM> is registered with RLOS of the IMS <NUM>.

According to a possible embodiment, the transceiver <NUM> can send a SIP INVITE request message to the network entity <NUM> based on an acceptance of the SIP REGISTER request message. According to a possible embodiment, the controller <NUM> can generate a Public key for the UE <NUM> and including the Public Key in the SIP REGISTER request message. According to a possible embodiment, the identification of the UE <NUM> can include at least one of an identification of the equipment of the UE <NUM> associated with an Attach procedure for the UE <NUM> and the IMPU. According to a possible embodiment, a validity time can be associated with the registered RLOS of the IMS <NUM>.

The methods of this disclosure can be implemented on a programmed processor.

While this disclosure has been described with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. For example, various components of the embodiments may be interchanged, added, or substituted in the other embodiments. Also, all of the elements of each figure are not necessary for operation of the disclosed embodiments. For example, one of ordinary skill in the art of the disclosed embodiments would be enabled to make and use the teachings of the disclosure by simply employing the elements of the independent claims. Accordingly, embodiments of the disclosure as set forth herein are intended to be illustrative, not limiting.

Claim 1:
A method performed by an apparatus, comprising:
performing (<NUM>) an attach procedure for restricted local operator services for the apparatus;
receiving (<NUM>) during the attach procedure an address for a proxy call session control function, the proxy call session control function address being dedicated for the restricted local operator services;
generating (<NUM>) a session initiation protocol register request message, the session initiation protocol register request message including an indication for the restricted local operator services and including an internet protocol multimedia public user identification based on an identification of the apparatus;
generating a public key for the apparatus and including the public key in the session initiation protocol register request message;
sending (<NUM>) the session initiation protocol register request message to the proxy call session control function address; and
receiving (<NUM>) a response message indicating the apparatus is registered with the restricted local operator services of an internet protocol multimedia core network subsystem (<NUM>).